Recent studies highlight the abundance of commensal coagulase-negative staphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin immunological and microbial milieu to resist colonization or infection by opportunistic pathogens, including methicillin resistant Staphylococcus aureus (MRSA), in a variety of mechanisms collectively termed colonization resistance. One potential colonization resistance mechanism is the application of quorum sensing, also called the Accessory Gene Regulator (agr) system, which is ubiquitous among staphylococci. Common and rare CoNS make autoinducing peptides (AIPs) that function as MRSA agr inhibitors, protecting the host from invasive infection. In a screen of CoNS spent media we found that Staphylococcus simulans, a rare human skin colonizer and frequent livestock colonizer, released potent inhibitors of all classes of MRSA agr signaling. We identified three S. simulans agr classes, and have shown intraspecies cross-talk between non-cognate S. simulans agr types for the first time. The S. simulans AIP-I structure was confirmed, and the novel AIP-II and AIP-III structures were solved via mass spectrometry. Synthetic S. simulans AIPs inhibited MRSA agr signaling with nanomolar potency. S. simulans in competition with MRSA reduced dermonecrotic and epicutaneous skin injury in murine models. Addition of synthetic AIP-I also effectively reduced MRSA dermonecrosis and epicutaneous skin injury in murine models. These results demonstrate potent anti-MRSA quorum sensing inhibition by a rare human skin commensal, and suggest that cross-talk between CoNS and MRSA may be important in maintaining healthy skin homeostasis and preventing MRSA skin damage during colonization or acute infection.

Klebsiella pneumoniae that produce extended spectrum beta lactamases (ESBLs) are a persistent public health threat. There are relatively few therapeutic options and there is undue reliance on carbapenems. Alternative therapeutic options are urgently required. A combination of cefepime and the novel beta lactamase inhibitor enmetazobactam is being developed for treatment of serious infections caused by ESBL-producing organisms. The pharmacokinetics-pharmacodynamics (PK-PD) of cefepime-enmetazobactam against ESBL-producing K. pneumoniae was studied in a neutropenic murine pneumonia model. Dose ranging studies were performed. Dose fractionation studies were performed to define the relevant PD index for the inhibitor. The partitioning of cefepime and enmetazobactam into the lung was determined by comparing area under the concentration time curve (AUC) in plasma and epithelial lining fluid. The magnitude of drug exposure for cefepime-enmetazobactam required for logarithmic killing in the lung was defined using 3 ESBL-producing strains. Cefepime 100 mg/kg q8h i.v. had minimal antimicrobial effect. When this background regimen of cefepime was combined with enmetazobactam half-maximal effect was induced with enmetazobactam 4.71 mg/kg q8h i.v. The dose fractionation study suggest both fT>threshold and fAUC:MIC are potentially relevant PD indices. The AUC_ELF:AUC_plasma for cefepime and enmetazobactam was 73.4% and 61.5%, respectively. A ≥2-log kill in the lung was achieved with a plasma and ELF cefepime fT>MIC of ≥20% and enmetazobactam fT>2 mg/L of ≥20% of the dosing interval. These data and analyses provide the underpinning evidence for the combined use of cefepime and enmetazobactam for nosocomial pneumonia.

The human diseases caused by the fungal pathogens Cryptococcus neoformans and C. gattii are associated with high indices of mortality, and toxic and/or cost-prohibitive therapeutic protocols. The need for affordable antifungals to combat cryptococcal disease is unquestionable. Previous studies suggested benzimidazoles as promising anti-cryptococcal agents combining low cost and high antifungal efficacy, but their therapeutic potential has not been demonstrated so far. In this study, we investigated the antifungal potential of fenbendazole, the most effective anti-cryptococcal benzimidazole. Fenbendazole was inhibitory against 17 different isolates of C. neoformans and C. gattii at a low concentration. The mechanism of anti-cryptococcal activity of fenbendazole involved microtubule disorganization, as previously described for human parasites. In combination with fenbendazole, the concentrations of the standard antifungal amphotericin B required to control cryptococcal growth were lower than those required when this antifungal was used alone. Fenbendazole was not toxic to mammalian cells. During macrophage infection, the anti-cryptococcal effects of fenbendazole included inhibition of intracellular proliferation rates and reduced phagocytic escape through vomocytosis. Fenbendazole deeply affected the cryptococcal capsule. In a mice model of cryptococcosis, the efficacy of fenbendazole to control animal mortality was similar to that observed for amphotericin B. These results indicate that fenbendazole is a promising candidate for the future development of an efficient and affordable therapeutic tool to combat cryptococcosis.

In vitro and in vivo interactions of minocycline and azoles including itraconazole, voriconazole, and posaconazole against filamentous pathogenic fungi were investigated. A total of 56 clinical isolates were studied in vitro via broth microdilution checkerboard technique, including 20 strains of Aspergillus fumigatus, 7 strains of A. flavus, 16 strains of Exophiala dermatitidis, 10 strains of Fusarium solani and 3 strain s of F. oxysporum. The results revealed that minocycline individually did not exhibit any significant antifungal activity against all tested strains. However, favorable synergy of minocycline with itraconazole, voriconazole, or posaconazole were observed against 34 (61%), 28 (50%), and 38 (69%) isolates, respectively, including azole resistant A. fumigatus and Fusarium spp. with inherently high MICs of azoles. Synergistic combinations resulted in 4 fold to 16-fold reduction of effective MICs of minocycline and azoles. No antagonism was observed. In vivo effect of minocycline-azole combinations were evaluated by survival assay in Galleria mellonella model infected with E. dermatitidis strain BMU00034, F. solani strain FS9, A. fumigatus strain AF293, AFR1 and AFR2 . Minocycline acted synergistically with azoles and significantly increased larvae survival in all isolates (P<0.001), including azole resistant A. fumigatus and azole-inactive Fusarium spp.. In conclusion, the results suggested that minocycline combined with azoles may help to enhance the antifungal susceptibilities of azoles against pathogenic fungi and had the potential to overcome azole resistance issues.

Spectinomycin is a ribosome-binding antibiotic that blocks the translocation step of translation. A prevalent resistance mechanism is the modification of the drug by aminoglycoside nucleotidyl transferase (ANT) enzymes of the spectinomycin-specific ANT (9) family or by the dual-specificity ANT(3") (9) family that also acts on streptomycin. We previously reported the structural mechanism of streptomycin modification by the ANT(3") (9) AadA from Salmonella enterica. ANT (9) from Enterococcus faecalis adenylates the 9-hydroxyl of spectinomycin. We here present the first structures of spectinomycin bound to an ANT enzyme. Structures were solved for ANT (9) in apo form, in complex with ATP, spectinomycin and magnesium or in complex with only spectinomycin. ANT (9) shows similar overall structure as AadA with an N-terminal nucleotidyltransferase domain and a C-terminal α-helical domain. Spectinomycin binds close to the entrance of the interdomain cleft, while ATP is buried at the bottom. Upon drug binding, the C-terminal domain rotates by 14 degrees to close the cleft, allowing contacts of both domains with the drug. Comparison with AadA shows that spectinomycin specificity is explained by a straight α₅ helix and a shorter α_5-α₆ loop that would clash with the larger streptomycin substrate. In the active site, we observe two magnesium ions, one of them in a previously un-observed position that may activate the 9-hydroxyl for deprotonation by the catalytic base Glu-86. The observed binding mode for spectinomycin suggests that also spectinamides and aminomethyl spectinomycins, recent spectinomycin analogues with expansions in position 4 of the C ring, will be subjected to modification by ANT (9) and ANT(3") (9) enzymes.

Carbapenem pharmacokinetic profiles are significantly changed in critically ill patients because of the drastic variability of the patients' physiological parameters. Published population PK studies have mainly focused on specific diseases and the majority of these studies had small sample sizes. The aim of this study was to develop a population PK model of imipenem in critically ill patients that estimated the influence of various clinical and biological covariates and the use of Extracorporeal Membrane Oxygenation (ECMO) and Continuous Renal Replacement Therapy (CRRT). A two-compartment population PK model with Creatinine clearance (CrCL), body weight (WT), and ECMO as fixed effects was developed using the non-linear mixed effect model (NONMEM). A Monte Carlo simulation was performed to evaluate various dosing schemes and different levels of covariates based on the pharmacokinetic/pharmacodynamic index (f%T>MIC) for the range of clinically relevant minimum inhibitory concentrations(MICs). The results showed that there may be insufficient drug use in the clinical routine drug dose regimen, and 750mg Q6h could achieve a higher treatment success rate. The blood concentrations of imipenem in ECMO patients were lower than that of non-ECMO patients, therefore dosage may need to be increased. The dosage may need adjustment for patients with CrCL ≤ 70ml/min, but dose should be lowered carefully to avoid the insufficient drug exposure. Dose adjustment is not necessary for patients within the WT ranging from 50-80 kg. Due to the large variation in PK profile of imipenem in critically ill patients, TDM should be carried out to optimize drug regimens.

Chromosomal and plasmid-borne AmpC cephalosporinases are a major resistance mechanism to β-lactams in Enterobacteriaceae and Pseudomonas aeruginosa. The new β-lactamase inhibitor avibactam effectively inhibits class C enzymes and can fully restore ceftazidime susceptibility. The conserved amino acid residue Asn³⁴⁶ of AmpC cephalosporinases directly interacts with the avibactam sulfonate. Disruption of this interaction caused by the N³⁴⁶Y amino acid substitution in Citrobacter freundii AmpC was previously shown to confer resistance to the ceftazidime-avibactam combination (CAZ-AVI). The aim of this study was to phenotypically and biochemically characterize the consequences of the N³⁴⁶Y substitution in various AmpC backgrounds. Introduction of N³⁴⁶Y into Enterobacter cloacae AmpC (AmpC_cloacae), plasmid-mediated DHA-1, and P. aeruginosa PDC-5, led to 270-, 12,000-, and 79-fold decreases in the inhibitory efficacy (k₂/K_i) of avibactam, respectively. The kinetic parameters of AmpC_cloacaeand DHA-1 for ceftazidime hydrolysis were moderately affected by the substitution. Accordingly, AmpC_cloacaeand DHA-1 harboring N³⁴⁶Y conferred CAZ-AVI resistance (MIC of ceftazidime of 16 µg/ml in the presence of 4 µg/ml of avibactam). In contrast, production of PDC-5 N³⁴⁶Y was associated with a lower MIC (4 µg/ml) since this β-lactamase retained a higher inactivation efficacy by avibactam in comparison to AmpC_cloacaeN³⁴⁶Y. For FOX-3, the I³⁴⁶Y substitution did not reduce the inactivation efficacy of avibactam and the substitution was highly deleterious for β-lactam hydrolysis, including ceftazidime, preventing CAZ-AVI resistance. Since AmpC_cloacaeand DHA-1 display substantial sequence diversity, our results suggest that loss of hydrogen interaction between Asn³⁴⁶ and avibactam could be a common mechanism of acquisition of CAZ-AVI resistance.

Brain infections with Cryptococcus neoformans are associated with significant morbidity and mortality. Cryptococcosis typically presents as meningoencephalitis or fungal mass lesions called cryptococcomas. Despite frequent in vitro discoveries of promising novel antifungals, the clinical need for drugs that can more efficiently treat these brain infections remains. A crucial step in drug development is the evaluation of in vivo drug efficacy in animal models. This mainly relies on survival studies or post-mortem analyses in large groups of animals, but these techniques only provide information on specific organs of interest at predefined time points. In this proof-of-concept study, we validated the use of non-invasive preclinical imaging to obtain longitudinal information on the therapeutic efficacy of amphotericin B or fluconazole monotherapy in meningoencephalitis and cryptococcoma mouse models. Bioluminescence imaging (BLI) enabled the rapid in vitro and in vivo evaluation of drug efficacy while complementary high-resolution anatomical information obtained by magnetic resonance imaging (MRI) of the brain allowed a precise assessment of the extent of infection and lesion growth rates. We demonstrated a good correlation between both imaging readouts and the fungal burden in various organs. Moreover, we identified potential pitfalls associated with the interpretation of therapeutic efficacy based solely on post-mortem studies, demonstrating the added value of this non-invasive dual imaging approach compared to standard mortality curves or fungal load endpoints. This novel preclinical imaging platform provides insights in the dynamic aspects of the therapeutic response and facilitates a more efficient and accurate translation of promising antifungal compounds from bench to bedside.

Bunyaviruses are significant human pathogens, causing diseases ranging from hemorrhagic fevers to encephalitis. Among these viruses, La Crosse virus (LACV), a member of the California serogroup, circulates in the eastern and midwestern United States. While LACV infection is often asymptomatic, dozens of cases of encephalitis are reported yearly. Unfortunately, no antivirals have been approved to treat LACV infection. Here, we developed a method to rapidly test potential antivirals against LACV infection. From this screen, we identified several potential antiviral molecules, including known antivirals. Additionally, we identified many novel antivirals that exhibited antiviral activity without affecting cellular viability. Valinomycin, a potassium ionophore, was among our top targets. We found that valinomycin exhibited potent anti-LACV activity in multiple cell types in a dose-dependent manner. Valinomycin did not affect particle stability or infectivity, suggesting that it may preclude virus replication by altering cellular potassium ions, a known determinant of LACV entry. We extended these results to other ionophores and found that the antiviral activity of valinomycin extended to other viral families including bunyaviruses (Rift Valley fever virus, Keystone virus), enteroviruses (Coxsackievirus, rhinovirus), flavirivuses (Zika), and coronaviruses (HCoV-229E and MERS-CoV). In all viral infections, we observed significant reductions in virus titer in valinomycin-treated cells. In sum, we demonstrate the importance of potassium ions to virus infection, suggesting a potential therapeutic target to disrupt virus replication.

Importance No antivirals are approved for the treatment of bunyavirus infection. The ability to rapidly screen compounds and identify novel antivirals is one means to accelerate drug discovery for viruses with no approved treatments. We used this approach to screen hundreds of compounds against La Crosse virus, an emerging bunyavirus that causes significant disease, including encephalitis. We identified several known and previously unidentified antivirals. We focused on a potassium ionophore, valinomycin, due to its promising in vitro antiviral activity. We demonstrate that valinomycin, as well as a selection of other ionophores, exhibits activity against La Crosse virus as well as several other distantly related bunyaviruses. We finally observe that valinomycin has activity against a wide array of human viral pathogens, suggesting that disrupting potassium ion homeostasis with valinomycin may be a potent host pathway to target to quell virus infection.

Ceftazidime–avibactam and cefiderocol are two of the latest generation β-lactam agents that possess expanded activity against highly drug-resistant bacteria, including carbapenem-resistant Enterobacterales. Here we show that structural changes in AmpC β-lactamases can confer reduced susceptibility to both agents. A multidrug-resistant Enterobacter cloacae clinical strain (Ent385) was found to be resistant to ceftazidime–avibactam and cefiderocol without prior exposure to either agent. The AmpC β-lactamase of Ent385 (AmpC^Ent385) contained an alanine–proline deletion at positions 294–295 (A294_P295del) in the R2 loop. AmpC^Ent385 conferred reduced susceptibility to ceftazidime–avibactam and cefiderocol when cloned into Escherichia coli TOP10. Purified AmpC^Ent385 showed increased hydrolysis of ceftazidime and cefiderocol compared with AmpC^Ent385Rev, in which the deletion was reverted. Comparisons of crystal structures of AmpC^Ent385 and AmpC^P99, the canonical AmpC of E. cloacae, revealed that the two-residue deletion in AmpC^Ent385 induced drastic structural changes of the H-9 and H-10 helices and the R2 loop, which accounted for the increased hydrolysis of ceftazidime and cefiderocol. The potential for a single mutation in ampC to confer reduced susceptibility to both ceftazidime–avibactam and cefiderocol requires close monitoring.

Importance Ceftazidime–avibactam and cefiderocol are newly approved β-lactam agents that possess broad spectrum activity against multidrug-resistant (MDR) Gram-negative bacteria. We show here that a two amino-acid deletion in the chromosomal AmpC β-lactamase, identified in a clinical strain of Enterobacter cloacae, confers reduced susceptibility to both agents. By crystallographic studies of free and drug-bound forms of enzyme, we demonstrate that this deletion in AmpC induces slanting of the H-9 helix that is directly connected with the R2 loop, and disappearance of the H-10 helix, is directly responsible for increased hydrolysis of ceftazidime and cefiderocol. These findings provide novel insights into how MDR Gram-negative bacteria may evolve their β-lactamases to survive selective pressure from these newly developed β-lactam agents.

Gepotidacin, a triazaacenaphthylene bacterial type II topoisomerase inhibitor, is in development for treatment of uncomplicated urinary tract infection (uUTI). This Phase 2a study in female participants with uUTI evaluated the pharmacokinetics (primary objective), safety, and exploratory efficacy of gepotidacin. Eligible participants (N = 22) were confined to the clinic at baseline, received oral gepotidacin 1,500 mg twice daily for 5 days (on-therapy; Days 1 to 5), and returned to the clinic for test-of-cure (Days 10 to 13) and follow-up (Day 28±3). Pharmacokinetic, safety, clinical, and microbiological assessments were performed. Maximum plasma concentrations were observed approximately 1.5 to 2 hours postdose. Steady state was attained by Day 3. Urinary exposure over the dosing interval increased from 3,742 μg.h/ml (Day 1) to 5,973 μg.h/ml (Day 4), with trough concentrations of 322 to 352 μg/ml from Day 3 onward. Gepotidacin had an acceptable safety-risk profile with no treatment-limiting adverse events and no clinically relevant safety trends. Clinical success was achieved in 19 (86%) and 18 (82%) of 22 participants at test-of-cure and follow-up, respectively. Eight participants had a qualifying baseline uropathogen (growth; ≥10⁵ CFU/ml). A therapeutic (combined clinical and microbiological [no growth; <10³ CFU/ml]) successful response was achieved in 6 (75%) and 5 (63%) of 8 participants at test-of-cure and follow-up, respectively. Plasma area under the free-drug concentration-time curve over 24 hours at steady state divided by the MIC (fAUC_0-24/MIC) and urine AUC_0-24/MIC ranged from 6.99 to 90.5 and 1,292 to 121,698, respectively. Further evaluation of gepotidacin in uUTI is warranted. (NCT03568942)

We report the first clinical Escherichia. coli strain EC3000 with concomitant chromosomal colistin and carbapenem resistance. A novel in-frame deletion, 6-11(RPISLR), in pmrB contributing to colistin resistance was verified using recombinant DNA techniques. Although decreased fitness compared to the wild-type (WT) strain or EC3000 revertant (chromosomal replacement of WT pmrB in EC3000), a portion of serially passaged EC3000 strains preserving colistin resistance without selective pressure raises the concern for further spread.

Treatment of dogs naturally infected with Leishmania infantum using meglumine antimoniate (MA) encapsulated in conventional liposomes (LC) in association with allopurinol has been previously reported to promote marked reduction in the parasite burden in the main infection sites. Here, a new assay in naturally infected dogs was performed using a novel liposome formulation of MA consisting of a mixture of conventional and long-circulating (PEGylated) liposomes (LCP), with expected broader distribution among affected tissues of the mononuclear phagocyte system. Experimental groups of naturally infected dogs were as follows: LCP+Allop, receiving LCP intravenously as 2 cycles of 6 doses (6.5 mg Sb/kg/dose) at 4-day intervals, plus allopurinol at 30 mg/kg/12 h p.o. during 130 days; LC+Allop, receiving LC intravenously as 2 cycles of 6 doses (6.5 mg Sb/kg/dose), plus allopurinol during 130 days; Allop, treated with allopurinol only; non-treated control. Parasite loads were evaluated by quantitative PCR in liver, spleen and bone marrow and by immunohistochemistry in the ear skin, before, just after treatment and 4 months later. LCP+Allop and LC+Allop groups, but not the Allop group, showed significant suppression of the parasites in the liver, spleen and bone marrow 4 months after treatment, compared to the pre-treatment period or the control group. Only LCP+Allop group showed significantly lower parasite burden in the skin, in comparison to the control group. On the basis of clinical staging and parasitological evaluations, LCP formulation exhibited a more favorable therapeutic profile, when compared to LC one, being therefore promising for treatment of canine visceral leishmaniasis.

The SHV β-lactamases (BLs) have undergone strong allele diversification that changed their substrate specificities. Based on 147 NCBI entries for SHV alleles, in silico mathematical models predicted five positions as relevant for the β-lactamase inhibitor (BLI) resistant (2br) phenotype, 12 as relevant for the extended-spectrum BL (ESBL) (2be) phenotype, and two positions were related to solely the narrow spectrum (2b) phenotype. These positions and additional 6 positions described in other studies (including one promoter mutation), were systematically substituted and investigated for their substrate specificities in a BL-free E. coli background, representing, to our knowledge, the most comprehensive substrate and substitution analysis for SHV alleles to date. An in vitro analysis confirmed the essentiality of the positions 238 and 179 for the 2be phenotype and 69 for the 2br phenotype. The substitutions E240K and E240R, which do not occur alone in known 2br SHV variants, led to a 2br phenotype, indicating a latent BLI-resistance potential of these substitutions. The substitutions M129V, A234G, S271I and R292Q conferred latent resistance to cefotaxime. In addition, 7 positions that were found to be not always associated with the ESBL phenotype resulted in increased resistance to ceftaroline. We also observed that coupling of a strong promoter (IS26) to a A146V mutant with the 2b phenotype resulted in a highly increased resistance to BLIs, cefepime and ceftaroline but not to 3^rd generation cephalosporins, indicating that SHV enzymes represent an underestimated risk for empirical therapies that use piperacillin/tazobactam or cefepime to treat different infectious diseases caused by gram-negatives.

Pharmacokinetic changes are often seen in patients with severe infections. Administration by continuous infusion has been suggested to optimize antibiotic exposure and pharmacokinetic/pharmacodynamic (PK/PD) target attainment for β-lactams. In an observational study, unbound piperacillin concentrations (n=196) were assessed in 78 critically ill patients following continuous infusion of piperacillin/tazobactam (ratio 8:1). The initial dose of 8, 12 or 16 g (piperacillin component) was determined by individual creatinine clearance (CRCL). Piperacillin concentrations were compared to the EUCAST clinical breakpoint MIC for Pseudomonas aeruginosa (16 mg/L), and the following PK/PD targets were evaluated: 100% fT>1xMIC and 100% fT>4xMIC. A population pharmacokinetic model was developed using NONMEM 7.4.3 consisting of a one-compartment disposition model with linear elimination separated into non-renal and renal (linearly increasing with patient CRCL) clearances. Target attainment was predicted and visualized for all individuals based on the utilized CRCL dosing algorithm. The target of 100% fT>1xMIC was achieved for all patients based on the administered dose, but few patients achieved the target of 100% fT>4xMIC. Probability of target attainment for a simulated cohort of patients showed, that increasing the daily dose by 4 g increments (piperacillin component) did not result in substantially improved target attainment for the 100% fT>4xMIC target. To conclude, in patients with high CRCL combined with high-MIC bacterial infections, even a CI regimen with a daily dose of 24 g may be insufficient to achieve therapeutic concentrations.

Attention has been paid to H5N6 highly pathogenic avian influenza virus (HPAIV) because of its heavy burden on the poultry industry and human mortality. Since an influenza A virus carrying N6 neuraminidase (NA) has never spread in humans, the potential for H5N6 HPAIV to cause disease in humans and the efficacy of antiviral drugs against the virus need to be urgently assessed. We used non-human primates to elucidate the pathogenesis of H5N6 HPAIV as well as to determine the efficacy of antiviral drugs against the virus. H5N6 HPAIV infection led to high fever in cynomolgus macaques. The lung injury caused by the virus was severe with diffuse alveolar damage and neutrophil infiltration. In addition, an increase in IFN-α showed an inverse correlation with virus titers during the infection process. Oseltamivir was effective for reducing H5N6 HPAIV propagation, and continuous treatment with peramivir reduced virus propagation and severity of symptoms in the early stage. This study also showed the pathologically severe lung injury states in the cynomolgus macaques infected with H5N6 HPAIV, even in those that received early antiviral drug treatments, indicating the need for close monitoring and the need for further studies on the virus pathogenicity and new antiviral therapies.

A total of 2,283 Salmonella spp. isolates were recovered from 18,334 samples including patients with diarrhea, food of animal origin and pets across 5 provinces of China. The highest prevalence of Salmonella spp. was detected in chicken meats (39.3%, 486/1,237). Fifteen serogroups and 66 serovars were identified, with Typhimurium and Enteritidis being the most dominant. Most (85.5%, 1,952/2,283) isolates exhibited resistant to ≥ 1 antimicrobial and 56.4% were multi-drug resistant (MDR). A total of 222 isolates harbored extended-spectrum β-lactamases (ESBLs), 200 of which were CTX-M-type that were mostly detected from chicken meat and turtle fecal. Overall, eight bla_CTX-M genes were identified, with bla_CTX-M-65, bla_CTX-M-123, bla_CTX-M-14, bla_CTX-M-79, and bla_CTX-M-130 being the most prevalent. Totally, 166 of the 222 ESBL-producing isolates had amino acid substitutions in GyrA (S83Y, S83F, D87G, D87N, and D87Y) and ParC (and S80I), whilst the PMQR-encoding genes oqxA/B, qepA, and qnrB/S were detected in almost all isolates. Of the fifteen sequence types (STs) identified in the 222 ESBLs, ST17, ST11, ST34, and ST26 ranked among the top 5 in the number of isolates. Our study revealed considerable serovars diversity, high prevalence of co-occurrence of MDR determinants, including CTX-M-type ESBLs, QRDRs mutations and PMQR genes. This is the first report of CTX-M-130 Salmonella spp. from patients with diarrhea and QRDRs mutations from turtle fecal samples. Our study emphasizes the importance of actions, both in the health care settings and in the veterinary medicine sector, to control the dissemination of MDR, especially the CTX-M Salmonella spp. isolates.

Baloxavir marboxil, a prodrug of cap-dependent endonuclease inhibitor, baloxavir acid, reduces the time to improvement of influenza symptoms in patients infected with type A or B influenza virus. To characterize its pharmacokinetics, a population pharmacokinetic model for baloxavir acid was developed using 11846 plasma concentration data items from 1827 subjects including 2341 plasma concentration data items from 664 patients at high risk of influenza complications. A three-compartment model with first-order elimination and first-order absorption with lag time well described the plasma concentration data. Body weight and race were found to be the most important factors influencing clearance and volume of distribution. The exposures in high-risk patients were similar to those in otherwise healthy patients, and no pharmacokinetic difference was identified regarding any risk factors for influenza complications.

Exposure-response analyses were performed regarding the time to improvement of symptoms and the reduction in the influenza virus titer in high-risk patients. The analyses suggested that body weight-based dosage, 40 mg for patients weighing < 80 kg and 80 mg for patients weighing ≥ 80 kg, can shorten the time to improvement of influenza symptoms and reduce virus titer for both type A and B influenza virus regardless of the exposure levels of the high-risk patients as well as for the otherwise healthy influenza patients.

The results of our population pharmacokinetic and exposure-response analyses in patients with risk factors of influenza complications should provide useful information on the pharmacokinetic and pharmacodynamic characteristics of baloxavir marboxil and also for the optimization of dose regimens.

Treatment of Mycobacterium avium complex pulmonary disease (MAC-PD) is challenging partly due to high efflux pump expression. Thioridazine might block these efflux pumps. We explore thioridazine's efficacy against M. avium using minimum inhibitory concentrations (MICs), time-kill combination assays, ex vivo macrophage infection assays and efflux assays. Thioridazine is bactericidal against M. avium, inhibits intracellular growth at 2x MIC and blocks ethidium bromide efflux. However, its toxicity and low plasma concentrations, make it unlikely to add efficacy to MAC-PD therapy.

Tedizolid has demonstrated its efficacy and safety in clinical trials, however, data concerning its tolerability in long-term treatments is scarce. The aim of the study was to assess the indications and to describe the long-term safety profile of tedizolid.

A multicentric, retrospective study of patients who received tedizolid for more than 6-days was conducted. Adverse events (AEs) were identified from patients' medical records and laboratory data. The World Health Organization causality categories were used to discern AEs probably associated with tedizolid.

Eighty-one patients, treated with tedizolid 200mg once-daily for a median (IQR) duration of 28 (14-59) days, were included, 36 (44.4%) had previously received linezolid. Most common reasons for selecting tedizolid were to avoid linezolid potential toxicities or interactions (53.1%) or due to previous linezolid-related toxicities (27.2%). Most common indications were off-label, including prosthetic joint infections, osteomyelitis and respiratory infections (77.8%). Overall, 9/81 patients (11.1%) experienced a probably associated AE. Two patients (2.5%) developed gastrointestinal disorders, 1 (1.2%) anemia and 6 thrombocytopenia (7.4%) after a median (IQR) duration of treatment of 26.5 (17-58.5) days. Four (5%) patients discontinued tedizolid due to AEs. Among 23 patients with chronic renal failure (CRF) the rate of mielotoxicity was 17.4% and only 8.7% had to stop tedizolid and 20 out of 22 with previous linezolid-associated toxicity had no AE.

Long-term tedizolid treatments had good tolerance with rates of gastrointestinal AE and hematological toxicity lower than those reported with linezolid, particularly in patients with CRF and in those with a previous history of linezolid-associated toxicity.

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with substantial morbidity and mortality. Monotherapy with first-line antimicrobials such as vancomycin (VAN; glycopeptide) and daptomycin (DAP; lipopeptide) are inadequate in some cases due to reduced antibiotic susceptibilities or therapeutic failure. In recent years, β-lactam antibiotics have emerged as a potential option for combination therapy with VAN/DAP that may meet an unmet therapeutic need for MRSA BSI. Ceftaroline (CPT), the only commercially available β-lactam in the United States with intrinsic in vitro activity against MRSA, has been increasingly studied in the setting of VAN and DAP failures. Novel combinations of first-line agents (VAN and DAP) with β-lactams have been the subject of many recent investigations due to in vitro findings such as the "see-saw effect", where β-lactam susceptibility may be improved in the presence of decreased glycopeptide and lipopeptide susceptibility. The combination of CPT and DAP, in particular, has become the focus of many scientific evaluations, due to intrinsic anti-MRSA activities and potent in vitro synergistic activity against various MRSA strains. This article reviews the available literature describing these innovative therapeutic approaches for MRSA BSI, focusing on preclinical and clinical studies, and evaluates the potential benefits and limitations of each strategy.

Globally, mutations in the katG gene account for the majority of isoniazid-resistant strains of Mycobacterium tuberculosis. Buyankhishig et al analyzed a limited number of Mycobacterium tuberculosis strains in Mongolia and found that isoniazid resistance was mainly attributable to inhA mutations. The GenoType® MTBDRplus assay was performed for isolates collected in the First National Tuberculosis Prevalence Survey and the Third Anti-Tuberculosis Drug Resistance Survey to investigate genetic mutations associated with isoniazid resistance in Mycobacterium tuberculosis in Mongolia. Of the 409 isoniazid-resistant isolates detected by the GenoType® MTBDRplus assay, 127 (31.1%) were resistant to rifampicin, 294 (71.9%) had inhA mutations without katG mutations, 113 (27.6%) had katG mutations without inhA mutations, and two (0.5%) strains had mutations in both the inhA and katG genes. Of the 115 strains with any katG mutation, 114 (99.1%) had mutations in codon 315 (S315T). Of the 296 trains with any inhA mutation, 290 (98.0%) had a C–15T mutation. The proportion of isoniazid-resistant strains with katG mutations was 25.3% among new cases and 36.2% among retreatment cases (p=0.03), as well as 17.0% among rifampicin-susceptible strains and 52.8% among rifampicin-resistant strains (p<0.01). Rifampicin resistance was significantly associated with the katG mutation (adjusted odds ratio 5.36, 95% CI 3.3–8.67, p<0.001). Mutations in inhA predominated in isoniazid-resistant tuberculosis in Mongolia. However, the proportion of katG mutations in isolates from previously treated cases was higher than that among new cases, and that in cases with rifampicin resistance was higher than that in cases without rifampicin resistance.

Dihydroartemisinin-piperaquine has shown excellent efficacy and tolerability in malaria treatment. However, concerns have been raised of potentially harmful cardiotoxic effects associated with piperaquine. The population pharmacokinetics and cardiac effects of piperaquine were evaluated in 1,000 patients, mostly children enrolled in a multicentre trial from 10 sites in Africa. A linear relationship described the QTc-prolonging effect of piperaquine, estimating a 5.90ms mean QTc-prolongation per 100ng/mL increase in piperaquine concentration. The effect of piperaquine on absolute QTc-interval estimated a mean maximum QTc-interval of 456ms (EC₅₀=209ng/mL). Simulations from the pharmacokinetic-pharmacodynamic models predicted 1.98-2.46% risk of having QTc-prolongation > 60ms in all treatment settings. Although piperaquine administration resulted in QTc-prolongation, no cardiovascular adverse events were found in these patients. Thus, the use of dihydroartemisinin-piperaquine should not be limited by this concern.

Meropenem/vaborbactam resistance in Klebsiella pneumoniae is associated with loss of function mutations in the OmpK35 and OmpK36 porins. Here we identify two previously unknown loss of function mutations that confer cefuroxime resistance in K. pneumoniae. The proteins lost were NlpD and KvrA; the latter is a transcriptional repressor controlling capsule production. We demonstrate that KvrA loss reduces OmpK35 and OmpK36 porin production, which confers reduced susceptibility to meropenem/vaborbactam in a KPC-3 producing K. pneumoniae isolate.

Aspergillus niger, the third species responsible for invasive aspergillosis has been considered as a homogeneous species until DNA-based identification uncovered many cryptic species. These species have been recently reclassified into the Aspergillus section Nigri. However little is yet known among the section Nigri about the species distribution and the antifungal susceptibility pattern of each cryptic species. A total of 112 clinical isolates collected from 5 teaching hospitals in France and phenotypically identified as A. niger were analyzed. Identification to the species level was carried out by nucleotide sequence analysis. The Minimum Inhibitory Concentrations (MICs) of itraconazole, voriconazole, posaconazole, isavuconazole and amphotericin B were determined by both the EUCAST and gradient concentration strips methods. Aspergillus tubingensis (n=51, 45.5%) and A. welwitschiae (n=50, 44.6%) were the most common species while A. niger accounted for only 6.3% (n=7). The MICs of azoles drugs were higher for A. tubingensis than for A. welwitschiae. The MIC of amphotericin B was 2 mg/L or less for all isolates. Importantly, MICs determined by EUCAST showed no correlation with those determined by gradient concentration strips methods, these latter being lower than the former (Spearman's rank correlation tests ranging - depending on the antifungal agent - from 0.01 to 0.25; p>0.4). In conclusion, A. niger should be considered as a minority species in the section Nigri. The differences in MICs between species for different azoles underline the importance of accurate identification. Significant divergences in the determination of MIC between EUCAST and gradient concentration strips methods require further investigation.

Staphylococcus aureus osteomyelitis is a debilitating infection of bone. Treatment of osteomyelitis is impaired by the propensity of invading bacteria to induce pathologic bone remodeling that may limit antibiotic penetration to the infectious focus. The nonsteroidal anti-inflammatory drug diflunisal was previously identified as an osteoprotective adjunctive therapy for osteomyelitis, based on the ability of this compound to inhibit S. aureus quorum sensing and subsequent quorum-dependent toxin production. When delivered locally during experimental osteomyelitis, diflunisal significantly limits bone destruction without affecting bacterial burdens. However, because diflunisal's "quorum-quenching" activity could theoretically increase antibiotic recalcitrance, it is critically important to evaluate this adjunctive therapy in the context of standard of care antibiotics. The objective of this study is to evaluate the efficacy of vancomycin to treat osteomyelitis during local diflunisal treatment. We first determined that systemic vancomycin effectively reduces bacterial burdens in a murine model of osteomyelitis, and identified a dosing regimen that decreases bacterial burdens without eradicating infection. Using this dosing scheme, we found that vancomycin activity is unaffected by the presence of diflunisal in vitro and in vivo. Similarly, locally-delivered diflunisal still potently inhibits osteoblast cytotoxicity in vitro and bone destruction in vivo in the presence of sub-therapeutic vancomycin. However, we also found that the resorbable polyurethane foams used to deliver diflunisal serve as a nidus for infection. Taken together, these data demonstrate that diflunisal does not significantly impact standard of care antibiotic therapy for S. aureus osteomyelitis, but also highlight potential pitfalls encountered with local drug delivery.

Anidulafungin and micafungin were quantified in cerebrospinal fluid (CSF) of critically ill adults and in cerebral cortex of deceased patients. In CSF, anidulafungin levels (<0.01-0.66 μg/ml) and micafungin levels (<0.01-0.16 μg/ml) were lower than the simultaneous plasma concentrations (0.77-5.07 μg/ml and 1.21-8.70 μg/ml, respectively). In cerebral cortex, anidulafungin and micafungin levels were 0.21-2.34 μg/g and 0.18-2.88 μg/g, respectively. Thus, MIC values of several pathogenic Candida strains exceed concentrations in CSF and in brain.

One of the reasons for the lengthy tuberculosis (TB) treatment is the difficult to treat non-multiplying mycobacterial subpopulation. In order to assess the ability of (new) TB drugs to target this subpopulation, we need to incorporate dormancy models in our pre-clinical drug development pipeline. In most available dormancy models it takes a long time to create a dormant state and it is difficult to identify and quantify this non-multiplying condition.

The Mycobacterium tuberculosis 18b strain might overcome some of these problems, because it is dependent on streptomycin for growth and becomes non-multiplying after 10 days of streptomycin starvation, but still can be cultured on streptomycin-supplemented culture plates. We developed our 18b dormancy time-kill kinetic model to assess the difference in the activity of isoniazid, rifampicin, moxifloxacin and bedaquiline against log-phase growth compared to the non-multiplying M. tuberculosis subpopulation by CFU counting including a novel AUC-based approach as well as time-to-positivity (TTP) measurements.

We observed that isoniazid and moxifloxacin were relatively more potent against replicating bacteria, while rifampicin and high dose bedaquiline were equally effective against both subpopulations. Moreover, the TTP data suggest that including a liquid culture-based method could be of additional value as it identifies a specific mycobacterial subpopulation that is non-culturable on solid media.

In conclusion, the results of our study underline that the time-kill kinetics 18b dormancy model in its current form is a useful tool to assess TB drug potency and thus has its place in the TB drug development pipeline.

Many transferable quinolone-resistance mechanisms have been already identified in Gram-negative bacteria. The plasmid-encoded 65 amino-acid long ciprofloxacin-modifying enzyme, namely CrpP, was recently identified in Pseudomonas aeruginosa. We analyzed a collection of 100 clonally-unrelated and multidrug-resistant P. aeruginosa clinical isolates among which 46 (46%) were found positive for crpP-like genes, encoding five CrpP variants conferring variable levels of reduced susceptibility to fluoroquinolones. Those crpP-like genes were chromosomally located, as part of PAGI-like pathogenicity genomic islands.

As resistance to artemisinins (current frontline drugs in malaria treatment) emerges in south East Asia, there is an urgent need to identify the genetic determinants and understand the molecular mechanisms underpinning such resistance. Such insights could lead to prospective interventions to contain resistance and prevent the eventual spread to other malaria endemic regions. Artemisinin reduced susceptibility in South East Asia (SEA) has been primarily linked to mutations in P. falciparum Kelch-13, which is currently widely recognised as a molecular marker of artemisinin resistance. However, 2 mutations in a ubiquitin hydrolase, UBP-1, have been previously associated with artemisinin reduced susceptibility in a rodent model of malaria and some cases of UBP-1 mutation variants associating with artemisinin treatment failure have been reported in Africa and SEA. In this study, we have employed CRISPR-Cas9 genome editing and pre-emptive drug pressures to test these artemisinin susceptibility associated mutations in UBP-1 in P. berghei sensitive lines in vivo. Using these approaches, we have shown that the V2721F UBP-1 mutation results in reduced artemisinin susceptibility, while the V2752F mutation results in resistance to chloroquine and moderately impacts tolerance to artemisinins. Genetic reversal of the V2752F mutation restored chloroquine sensitivity in these mutant lines while simultaneous introduction of both mutations could not be achieved and appears to be lethal. Interestingly, these mutations carry a detrimental growth defect, which would possibly explain their lack of expansion in natural infection settings. Our work has provided independent experimental evidence on the role of UBP-1 in modulating parasite responses to artemisinin and chloroquine under in vivo conditions.

Chagas disease, caused by the protozoan Trypanosoma cruzi, is one of the main causes of death due to cardiomyopathy and heart failure in Latin American countries. The treatment of Chagas disease is directed at eliminating the parasite, decreasing the probability of cardiomyopathy, and disrupting the disease transmission cycle. Benznidazole (BZ) and nifurtimox (NFX) are recognized as effective drugs for the treatment of Chagas disease by the World Health Organization, but both have high toxicity and limited efficacy, especially in the chronic disease phase. At low doses, aspirin (ASA) has been reported to protect against T. cruzi infection. We evaluated the effectiveness of BZ in combination with ASA at low doses during the acute disease phase and evaluated cardiovascular aspects and cardiac lesions in the chronic phase. ASA treatment prevented the cardiovascular dysfunction (hypertension and tachycardia) and typical cardiac lesions. Moreover, BZ+ASA-treated mice had a smaller cardiac fibrotic area than that in BZ-treated mice. These results were associated with an increase in the number of eosinophils and reticulocytes and level of nitric oxide in the plasma and cardiac tissue of ASA-treated mice relative to respective controls. These effects of ASA and BZ+ASA in chronically infected mice were inhibited by pretreatment with the LXA₄ receptor antagonist, Boc-2, indicating that the protective effects of ASA are mediated by ASA-triggered lipoxin. These results emphasize the importance of exploring new drug combinations for treatments of acute phase of Chagas disease that are beneficial for chronic patients.

Two non-amidated host defence peptides named Pin2[G] and FA1 were evaluated against three types of pathogenic bacteria; two isolated from diabetic foot ulcer patients, Staphylococcus aureus UPD13 and Pseudomonas aeruginosa UPD3, and another from a commercial collection, Salmonella enterica serovar Typhimurium (ATCC 14028). In vitro experiments showed that the antimicrobial performance of the synthetic peptides, Pin2[G] and FA1, was modest, although FA1 was more effective than Pin2[G]. In contrast Pin2[G] had superior in vivo anti-infective activity to FA1 in rabbit wound infections by the diabetic foot ulcer pathogens S. aureus UPD13 and P. aeruginosa UPD3. Indeed, Pin2[G] reduced bacterial colony counts of both S. aureus UPD13 and P. aeruginosa UPD3 by >100,000-fold after 48-72 h on skin wounds of infected rabbits, while in similar infected wounds, FA1 had no major effects at 72-96 h of treatment. Ceftriaxone was equally effective vs. Pseudomonas but less effective vs. S. aureus infections. Additionally, the two peptides were evaluated in mice against intragastrically inoculated S. enterica ser. Typhimurium (ATCC 14028). Only Pin2[G], at 0.56 mg/kg, was effective in reducing systemic (liver) infection by >67-fold, equivalent to the effect of treatment with levofloxacin. Pin2[G] showed superior immunomodulatory activity in increasing chemokine production by a human bronchial cell line and suppressing poly(IC)-induced pro-inflammatory IL6 production. These data showed that the in vitro antimicrobial activity of these peptides was not correlated with their in vivo anti-infective activity, and suggest that other factors such as immunomodulatory activity were more important.

Florfenicol belongs to a class of phenicol antimicrobials widely used as feed additives and for the treatment of respiratory infections. In recent years, increasing resistance to florfenicol has been reported in Campylobacter spp., the leading foodborne enteric pathogen causing diarrheal diseases worldwide. Here, we reported the identification of fexA, a novel mobile florfenicol resistance gene in Campylobacter. Of the 100 Campylobacter jejuni strains isolated from poultry in Zhejiang, China, nine of them were shown to be fexA positive, and their whole genome sequences were further determined by integration of Illumina short-read and MinION long-read sequencing. The fexA gene was found in the plasmid of one strain and chromosomes of eight strains, and its location was verified by S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting. Based on comparative analysis, the fexA gene was located within a region with the tet(L)-fexA-catA-tet(O) gene arrangement, demonstrated to be successfully transferrable among C. jejuni strains. Functional cloning indicated that acquisition of the single fexA gene significantly increased resistance to florfenicol, whereas its inactivation resulted in increased susceptibility to florfenicol in Campylobacter. Taken together, these results indicated that the emerging fexA resistance is horizontally transferable, which might greatly facilitate the adaptation of Campylobacter in food producing environments where florfenicols are frequently used.

Methicillin-resistant Staphylococcus aureus (MRSA) has grown to become a major burden on healthcare systems. The cumulation of limited therapeutic options and worsened patient outcomes with persistent MRSA bacteremia has driven research in optimizing its initial management. The guidelines published by the Infectious Disease of America currently recommend combination therapy for refractory MRSA bacteremia, but the utility of combining antibiotics from the start of therapy is under investigation. The alternative strategy of early use of a β-lactam antibiotics in combination with vancomycin upon initial MRSA bacteremia detection has shown promise. While this concept has gained international attention, providers should give this strategy serious consideration prior to implementation. The objective of this review is to examine retrospective and prospective evidence for early combination with vancomycin and β-lactam antibiotics, as well as explore potential consequences of combination therapy.

Manogepix (APX001A) is the active moiety of the novel drug candidate fosmanogepix (APX001). We previously reported the broad-spectrum activity of manogepix but also observed a correlation between increased manogepix and fluconazole MICs. Here we extended this study and included isolates with acquired fluconazole resistance.

Isolates (n=835) were identified using CHROMagar, MALDI-TOF and, when needed, ITS-sequencing. EUCAST E.Def 7.3.1 susceptibility testing included manogepix, amphotericin B, anidulafungin, micafungin, fluconazole and voriconazole. Manogepix wildtype-upper-limit (WT-UL) values were established following EUCAST-principles for ECOFF setting allowing wildtype/non-wildtype classification. Drug-specific MIC correlations were investigated using Pearson's correlation.

Manogepix modal MICs were low (range 0.004-0.06 mg/L against 16/20 included species). Exceptions were C. krusei and C. inconspicua, and to a lesser extent C. kefyr and Pichia kluyveri. The activity was independent of Fks echinocandin hot-spot alterations (n=17). Adopting the WT-UL established for C. albicans, C. dubliniensis, C. glabrata, C. parapsilosis and C. tropicalis, 14/724 (1.9%) isolates were non-wildtype for manogepix. Twelve of these (85.7%) were also non-wildtype for fluconazole. A statistically significant correlation was observed between manogepix and fluconazole MICs for C. albicans, C. dubliniensis, C. glabrata, C. parapsilosis and C. tropicalis (Pearson r=0.401-0.575), but not between manogepix and micafungin or amphotericin B MICs for any species except C. tropicalis (r=0.519 for manogepix versus micafungin).

Broad-spectrum activity was confirmed for manogepix against contemporary yeast. However, a 1-4 two-fold-dilution increase in manogepix MICs is observed in a subset of isolates with acquired fluconazole resistance. Further studies on the potential underlying mechanism and implication for optimal dosing are warranted.

Treatment of exacerbations of chronic Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) is highly challenging due to hypermutability, biofilm formation and an increased risk of resistance emergence. We evaluated the impact of ciprofloxacin and meropenem as monotherapy and in combination in the dynamic in vitro CDC biofilm reactor (CBR). Two hypermutable P. aeruginosa strains, PAOmutS (MIC_{ciprofloxacin} 0.25 mg/L, MIC_meropenem 2 mg/L) and CW44 (MIC_{ciprofloxacin} 0.5 mg/L, MIC_meropenem 4 mg/L), were investigated for 120h. Concentration-time profiles achievable in epithelial lining fluid (ELF) following FDA-approved doses were simulated in the CBR. Treatments were ciprofloxacin 0.4g every 8h as 1h-infusions (80% ELF penetration), meropenem 6 g/day as continuous infusion (CI; 30% and 60% ELF penetration) and their combinations. Counts of total and less-susceptible planktonic and biofilm bacteria and MICs were determined. Antibiotic concentrations were quantified by UHPLC-PDA. For both strains, all monotherapies failed with substantial regrowth and resistance of planktonic (≥8log₁₀ CFU/mL) and biofilm (>8log₁₀ CFU/cm²) bacteria at 120h (MIC_{ciprofloxacin} up to 8 mg/L, MIC_meropenem up to 64 mg/L). Both combination treatments demonstrated synergistic bacterial killing of planktonic and biofilm bacteria of both strains from ~48h onwards and suppressed regrowth to ≤4log₁₀ CFU/mL and ≤6log₁₀ CFU/cm² at 120h. Overall, both combination treatments suppressed amplification of resistance of planktonic bacteria for both strains, and biofilm bacteria for CW44. The combination with meropenem at 60% ELF penetration also suppressed amplification of resistance of biofilm bacteria for PAOmutS. Thus, combination treatment demonstrated synergistic bacterial killing and resistance suppression against difficult-to-treat hypermutable P. aeruginosa strains.

Peroxidases are a group of heterogeneous family of enzyme that plays diverse biological functions. Ascorbate peroxidase is a redox enzyme that is reduced by trypanothione, which plays a central role in the redox defence system of Leishmania. In view of developing new and novel therapeutics, we have performed in silico studies in order to search for ligand library and identification of new drug candidates and its physiological role against promastigotes and intracellular amastigotes of Leishmania donovani. Our results demonstrated that the selected inhibitor ZINC96021026 has significant anti-leishmanial effect and effectively killed both free and intracellular forms of the parasite. ZINC96021026 was found to be identical to ML-240, a selective inhibitor of Valosin-containing protein (VCP) or p97, a member of AAA-ATPase protein family which was derived from the scaffold of DBeQ, targeting the D2-ATPase domain of the enzyme. ZINC96021026 (ML-240) thus have broad range of cellular functions, thought to be derived from its ability to unfold proteins or disassemble protein complexes besides inhibiting the ascorbate peroxidase activity. ML-240 may inhibits the parasite's ascorbate peroxidase leading to extensive apoptosis and inducing generation of reactive oxygen species. Taken together, our results demonstrated that ML-240 could be an attractive therapeutic option for treatment against leishmaniasis.

CYP450 enzymes are involved in biotransformation of chloroquine (CQ), but the role of the different metabolism profiles of this drug has not been properly investigated in relation to P. vivax recurrences. To investigate the influence of CYPs genotypes associated with CQ-metabolism on early recurrence rates of P. vivax, a case-control study was carried out. Cases included patients presenting an early recurrence (CQ-recurrent), defined as recurrence during the first 28 days after initial infection, plasma concentrations of CQ plus desethylchloroquine (DCQ, the major CQ metabolite) higher than 100 ng/mL. A control (CQ-responsive) with no parasite recurrence over the follow-up was also included. CQ and DCQ plasma levels were measured on Day 28. CQ CYPs (CYP2C8, CYP3A4 and CYP3A5) genotypes were determined by real-time PCR. An ex vivo study was conducted to verify CQ and DCQ efficacy in P. vivax isolates. The frequency of alleles associated with normal and slow metabolism was similar between the cases and controls for CYP2C8 (OR=1.45, 95% CI=0.51-4.14, p=0.570), CYP3A4 (OR=2.38, 95% CI=0.92-6.19, p=0.105) and CYP3A5 (OR=4.17, 95% CI=0.79-22.04, p=1.038) genes. DCQ levels were higher than CQ, regardless of the genotype. Regarding the DCQ/CQ rate, there was no difference between groups or between those patients who had a normal or mutant genotype. DCQ and CQ showed similar efficacy ex vivo. CYPs genotypes had no influence on early recurrence rates. Similar efficacy of CQ and DCQ ex vivo could explain the absence of therapeutic failure, despite presence of alleles associated with slow metabolism.

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Global markets rallied on the back of optimism that most governments were gearing up to at least partially reopen their economies following lockdowns to prevent the spread of the coronavirus.

In number 10 in our countdown, I tried to offer a few thoughts to funders as they embraced new agendas and looked to avoid repeating yesterday's missteps.

BACKGROUND AND OBJECTIVES:

Antibiotic therapy is often prescribed for suspected community-acquired pneumonia (CAP) in children despite a lack of knowledge of causative pathogen. Our objective in this study was to investigate the association between antibiotic prescription and treatment failure in children with suspected CAP who are discharged from the hospital emergency department (ED).

BACKGROUND:

Approximately 25% of children with concussion have persistent postconcussive symptoms (PPCS) with resultant significant impacts on quality of life. Melatonin has significant neuroprotective properties, and promising preclinical data suggest its potential to improve outcomes after traumatic brain injury. We hypothesized that treatment with melatonin would result in a greater decrease in PPCS symptoms when compared with a placebo.

BACKGROUND:

Mexican-origin women breastfeed at similar rates as white women in the United States, yet they usually breastfeed for less time. In our study, we seek to identify differences in Mexican-origin women’s breastfeeding intentions, initiation, continuation, and supplementation across nativity and country-of-education groups.

BACKGROUND:

Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly with a mortality of ~27%. The Congenital Diaphragmatic Hernia Study Group (CDHSG) developed a simple postnatal clinical prediction rule to predict mortality in newborns with CDH. Our aim for this study is to externally validate the CDHSG rule in the European population and to improve its prediction of mortality by adding prenatal variables.

BACKGROUND AND OBJECTIVES:

Children born very preterm (VPT) are at high risk of cognitive impairment that impacts their educational and social opportunities. This study examined the predictive accuracy of assessments at 2, 4, 6, and 9 years in identifying preterm children with cognitive impairment by 12 years.

BACKGROUND:

Current guidelines from the American Academy of Pediatrics recommend screening children for developmental problems by using a standardized screening tool and referring at-risk patients to early intervention (EI) or subspecialists. Adoption of guidelines has been gradual, with research showing many children still not being screened and referred.

BACKGROUND AND OBJECTIVES:

The albuterol dropper bottle used to prepare solutions for continuous nebulization contains the preservative benzalkonium chloride (BAC). BAC, by itself, has been shown to cause bronchospasm. We hypothesized that BAC would decrease the therapeutic efficacy of albuterol in patients with acute asthma exacerbations.

The Nanit Plus offers more features and data than any other smart baby monitor, including sleep tracking and breathing monitoring.

Campaign Monitor is a satisfactory marketing tool, especially with email marketing features and analytics, but it trails the competition in areas like direct online support.