Antimicrobial Agents and Chemotherapy最新文献

ZSP1273 is a novel small-molecule anti-influenza drug that targets the RNA polymerase PB2 subunit, while oseltamivir is the first-line medication that inhibits neuraminidase. ZSP1273 showed high efficacy against human influenza viruses both in vitro and in vivo, including oseltamivir-resistant strains in vitro. In future clinical applications, the combination of these two antiviral drugs with different mechanisms can reduce the potential for antiviral resistance that may arise from monotherapy. To evaluate the drug-drug interaction between ZSP1273 and oseltamivir by the pharmacokinetics and safety of co-administration in healthy subjects, a phase I, single-center, randomized, open-label, three-period crossover study was conducted. Thirty-six subjects enrolled were randomized in a 1:1:1 ratio into three crossover treatment sequences with oral administration detailed as follows: treatment A: ZSP1273 tablets 600 mg once daily (QD) for 5 days; treatment B: oseltamivir capsules 75 mg twice daily (BID) for 5 days; treatment C: ZSP1273 tablets 600 mg once daily (QD) + oseltamivir capsules 75 mg twice daily (BID) for 5 days. Plasma samples were collected from all subjects at scheduled time points after drug administration to measure the plasma concentrations of ZSP1273, oseltamivir, and its active metabolite oseltamivir carboxylate, for pharmacokinetic analysis. Compared with monotherapy, the geometric mean ratios (90% confidence intervals) of C_max,ss, AUC_0-t,ss, AUC_0-τ,ss, and AUC_0-∞,ss for ZSP1273 after co-administration were all within the ineffective boundary range of 80% to 125%, supporting that no drug-drug interaction occurs with ZSP1273. After co-administration, the AUC_0-t,ss, AUC_0-τ,ss, and AUC_0-∞,ss of oseltamivir were all within 80% to 125%, while C_max,ss decreased by 39.9%. The pharmacokinetic parameters above of oseltamivir carboxylate remained within 80%-125%, except only the lower bound of the 90% CI for C_max,ss slightly below 80% (77.0%). Considering the rapid metabolism of oseltamivir into the active metabolite oseltamivir carboxylate and the minor impact of co-administration on the pharmacokinetic parameters of oseltamivir carboxylate, it is believed that no clinically significant drug-drug interaction was observed with the combination of these two drugs. During the trial, the safety and tolerability of both combination therapy and monotherapy were good, with no increased safety risks observed from the combination therapy.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT05108051.

A hub and spoke model for optimizing long-term treatment of chronic staphylococcal infections with dalbavancin based on therapeutic drug monitoring (TDM)-guided expert clinical pharmacological advice (ECPA) was implemented. This multicentric retrospective cohort study included patients receiving dalbavancin monotherapy lasting >6 weeks at different spoke hospitals having treatment optimized by means of a TDM-guided ECPA program at a hub hospital. Optimal pharmacokinetic/pharmacodynamic target against staphylococci with an MIC up to 0.125 mg/L was defined as dalbavancin concentrations >8.04 mg/L. Patients received dalbavancin therapy for curative (curative group) or suppressive (suppressive group) purposes. Clinical outcome was assessed by means of repeated ambulatory visits. A total of 12 spoke hospitals applied for 414 TDM-based ECPA for 101 patients, of whom 64.4% (65/101) were treated for curative and 35.6% (36/101) were for suppressive purposes. In the curative and suppressive groups, TDM-based ECPA optimized treatment for up to 14 and 28 months, respectively, and ensured median optimal exposure of 95.7% and 100%, respectively. In the curative group, having <70% of treatment time with concentrations above the optimal target increased failure risk [odds ratio (OR), 6.71; confidence interval (CI), 0.97-43.3; P = 0.05]. In the suppressive group, infective endocarditis was associated with an increased risk of ineffective treatment (OR, 8.65; CI, 1.29-57.62; P = 0.046). Mild adverse events were reported in 4.5% (5/101) of cases. A hub and spoke TDM-guided ECPA program of dalbavancin may be cost-effective for optimizing long-term treatment of chronic staphylococcal infections and for patients admitted to hospitals lacking in-house MD clinical pharmacologists.

Malaria parasites acquire drug resistance through genetic changes, the mechanisms of which remain incompletely understood. Understanding the mechanisms of drug resistance is crucial for the development of effective treatments against malaria, and for this purpose, new genetic tools are needed. In a previous study, as a forward genetic tool, we developed the rodent malaria parasite Plasmodium berghei mutator (PbMut) line, which has a greatly increased rate of mutation accumulation and from which we isolated a mutant with reduced susceptibility to piperaquine (PPQ). We identified a mutation in the chloroquine resistance transporter (PbCRT N331I) as responsible for this phenotype. In the current study, we generated a marker-free PbMut to enable further genetic manipulation of the isolated mutants. Here, we screened again for PPQ-resistant mutants in marker-free PbMut and obtained a parasite population with reduced susceptibility to PPQ. Of five isolated clones, none had the mutation PbCRT N331I; rather, they possessed a nonsense mutation at amino acid 119 (PbCRT Y119*), which would truncate the protein before eight of its ten predicted transmembrane domains. The PbCRT orthologue in the human malaria parasite Plasmodium falciparum, PfCRT, is an essential membrane transporter. To address the essentiality of PbCRT, we successfully deleted the full PbCRT gene [PbCRT(-)] from wild-type parasites. PbCRT(-) parasites exhibited reduced susceptibility to PPQ, along with compromised fitness in mice and following transmission to mosquitoes. Taken together, our findings provide the first evidence that P. berghei can acquire reduced PPQ susceptibility through complete loss of PbCRT function.

Primaquine is the only widely available drug to prevent relapses of Plasmodium vivax malaria. Primaquine is underused because of concerns over oxidant hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficiency. A pharmacometric trial showed that ascending-dose radical cure primaquine regimens causing 'slow burn' hemolysis were safe in G6PD-deficient Thai and Burmese male volunteers. We developed and calibrated a within-host model of primaquine hemolysis in G6PD deficiency, using detailed serial hemoglobin and reticulocyte count data from 23 hemizygote deficient volunteers given ascending-dose primaquine (1,523 individual measurements over 656 unique time points). We estimate that primaquine doses of ~0.75 mg base/kg reduce the circulating lifespan of deficient erythrocytes by ~30 days in individuals with common Southeast Asian G6PD variants. We predict that 5 mg/kg primaquine total dose can be administered safely to G6PD-deficient individuals over 14 days with expected hemoglobin drops of 18 to 43% (2.7 to 6.5 g/dL drop from a baseline of 15 g/dL).CLINICAL TRIALSThis study is registered with the Thai Clinical Trials Registry (TCTR) as TCTR20170830002 and TCTR20220317004.

Despite the various strategies that microorganisms have evolved to resist antibiotics, survival to drug treatments can be driven by subpopulations of susceptible bacteria in a transient state of dormancy. This phenotype, known as bacterial persistence, arises due to a natural and ubiquitous heterogeneity of growth states in bacterial populations. Nonetheless, the unifying mechanism of persistence remains unknown, with several pathways being able to trigger the phenotype. Here, we show that asymmetric damage partitioning, a form of cellular aging, produces the underlying phenotypic heterogeneity upon which persistence is triggered. Using single-cell microscopy and microfluidic devices, we demonstrate that deterministic asymmetry in exponential phase populations leads to a state of growth stability, which prevents the spontaneous formation of persisters. However, as populations approach stationary phase, aging bacteria-those inheriting more damage upon division-exhibit a sharper growth rate decline, increased probability of growth arrest, and higher persistence rates. These results indicate that persistence triggers are biased by bacterial asymmetry, thus acting upon the deterministic heterogeneity produced by cellular aging. This work suggests unifying mechanisms for persistence and offers new perspectives on the treatment of recalcitrant infections.

Ibezapolstat (IBZ), a first-in-class antibiotic targeting the PolC-type DNA polymerase III alpha-subunit (PolC) in low G + C bacteria, is in clinical development for the treatment of Clostridioides difficile infection (CDI). In the phase 2 trials, IBZ had potent activity against C. difficile while sparing or causing regrowth of Lachnospiraceae, Oscillospiraceae, and Erysipelotrichales, common commensal low G + C bacteria. The purpose of this study was to utilize in silico approaches to better interpret the narrower than expected IBZ spectrum of activity. IBZ susceptibility to human commensal microbiota was predicted using genomic analysis and PolC phylogenetic tree construction in relation to C. difficile and commensal low G + C bacteria. Protein structure prediction was performed using AlphaFold2 and binding pocket homology modeling was performed using Schrodinger Maestro and UCSF ChimeraX. An amino acid phylogenetic tree identified certain residues that were phylogenetically variant in Lachnospiraceae, Oscillospiraceae, and Erysipelotrichales and conserved in C. difficile. Chemical modeling showed that these residues ablated key PolC•IBZ predicted interactions including two lysine "gates" (_CdiPolCLys1148 and _CdiPolCLys1327) that "latch" onto the compound; an "anchoring" interaction (_CdiPolCThr1331) to the central moiety; and a stabilized set of C. difficile sensitizer residues (_CdiPolCThr1291 and _CdiPolCLys1292) that resulted in the prolonged inhibition of a catalytic residue (_CdiPolCAsp1090). The observed IBZ sparing of Lachnospiraceae, Oscillospiraceae, and Erysipelotrichaceae/Coprobacillaceae was predicted using in silico techniques. Further studies that confirm a PolC structural basis for the IBZ narrower than expected activity are needed to confirm these in silico phylogenetic and chemical modeling data.

Decades of antibiotic misuse have accelerated the emergence of multi- and extensively drug-resistant bacteria. Bacterial pathogens employ several strategies such as antibiotic resistance, tolerance, and biofilm formation in response to extreme environments and antibiotic stress. Another crucial survival mechanism involves the stochastic generation of bacterial subpopulations known as persisters, which can endure high concentrations of antibiotics. Upon removal of antibiotic stress, these subpopulations revert back to their original phenotype which links them to the relapse and recalcitrance of chronic infections, a significant problem in clinical settings. Persistent infections are particularly notable in Acinetobacter baumannii, a top-priority ESKAPE pathogen, where carbapenems serve as last-resort antibiotics. Several reports indicate the rising therapeutic failure of carbapenems due to persistence, underscoring the importance of developing anti-persister therapeutics. In this study, we explored the mechanisms of transient persister formation in A. baumannii against meropenem. Our investigation revealed significant changes in membrane properties and energetics in meropenem persisters of A. baumannii, including a noteworthy increase in tolerance to other antibiotics. This understanding guided the evaluation of an in-house collection of GRAS status compounds for their potential anti-persister activity. The compound thymol demonstrated remarkable inhibitory activity against meropenem persisters of A. baumannii and other ESKAPE pathogens. Further investigation revealed its impact on persister cell physiology, including efflux pump inhibition and disruption of cellular respiration. Given our results, we propose a compelling strategy where thymol could be employed either as a monotherapy or in combination with meropenem in anti-persister therapeutics.

Doravirine (DOR) is a novel antiretroviral agent with a favorable resistance profile and high tolerability. However, evidence is limited on DOR among elderly people living with HIV (PLWH) and whether it might modulate chronic inflammation. We aimed to investigate the efficacy, safety, and tolerability of DOR as a switching strategy among elderly PLWH and its impact on chronic inflammation in a real-life setting. We recruited a cohort of ART-experienced PLWH undergoing a therapeutic switch to a DOR-based regimen under virologic control (defined as HIV-RNA <200 copies/mL), regardless of the previous ART regimen. The primary objective was the evaluation of the rate of virologic control at 48 weeks post-switch. Secondary objectives included analyzing immune and metabolic outcomes. Plasmatic hs-CRP, IL-6, and D-dimer levels were measured as chronic inflammation markers. Overall, 150 PLWH were screened, and 147 were enrolled into the study. A total of 134 PLWH completed the follow-up. The rate of virological control was 96.1% (122/134; CIs: 91.0%-98.7%) in the per-protocol analysis. After 48 weeks from the switch, we recorded significant reductions in serum fasting glycemia (P 0.019), triglycerides (P 0.024), and total cholesterol/HDL ratio (P 0.017); no clinically significant differences were detected in the body weight and BMI, as long as in immune, hepatic, and renal profiles. A significant reduction in IL-6 (P 0.019) and hs-CRP (P 0.019) was observed. DOR is an effective and safe treatment choice for elderly PLWH. The intriguing modulatory effect of DOR-based regimens on chronic systemic inflammation deserves further investigation.

Candida auris is an emerging pathogenic fungus that is highly resistant to existing antifungal drugs. Manogepix is a novel antifungal agent that exerts antifungal activity by inhibiting glycosylphosphatidylinositol anchor biosynthesis. Although the mechanisms of resistance of Candida species to manogepix have been reported previously, those of C. auris are yet to be studied. To investigate the resistance mechanisms of C. auris, we exposed a clinical isolate (clade I) to manogepix in vitro and generated strains with reduced susceptibility to manogepix. A search for gain-of-function mutations that upregulate efflux pump expression confirmed the presence of the D865N amino acid mutation in TAC1b. We used the clustered regularly interspaced short palindromic repeats-Cas9 system to create a recovery strain (N865D) in which only this single nucleotide mutation was returned to the wild-type sequence. We generated a mutant strain by introducing only the D865N mutation into the parent strain and a different clade strain (clade III). The D865N mutant strains were clearly less susceptible to manogepix than the parental strains and exhibited high CDR1 expression. Moreover, we generated a strain deficient in CDR1 and confirmed that this strain had significantly increased susceptibility to manogepix. Thus, the present study demonstrated that the TAC1b mutation in C. auris upregulates CDR1 expression and decreases its susceptibility to manogepix.

Bacteriophages are an increasingly attractive option for the treatment of antibiotic-resistant infections, but their efficacy is difficult to discern due to the confounding effects of antibiotics. Phages are generally delivered in conjunction with antibiotics, and thus, when patients improve, it is unclear whether the phages, antibiotics, or both are responsible. This question is particularly relevant for enterococcus infections, as limited data suggest phages might restore antibiotic efficacy against resistant strains. Enterococci can develop high-level resistance to vancomycin, a primary treatment. We assessed clinical and laboratory isolates of Enterococcus faecium and Enterococcus faecalis to determine whether we could observe synergistic interactions between phages and antibiotics. We identified synergy between multiple phages and antibiotics including linezolid, ampicillin, and vancomycin. Notably, antibiotic susceptibility did not predict synergistic interactions with phages. Vancomycin-resistant isolates (n = 6) were eradicated by the vancomycin-phage combination as effectively as vancomycin-susceptible isolates (n = 2). Transcriptome analysis revealed significant gene expression changes under antibiotic-phage conditions, especially for linezolid and vancomycin, with upregulated genes involved in nucleotide and protein biosynthesis and downregulated stress response and prophage-related genes. While our results do not conclusively determine the mechanism of the observed synergistic interactions between antibiotics and phages, they do confirm and build upon previous research that observed these synergistic interactions. Our work highlights how using phages can restore the effectiveness of vancomycin against resistant isolates. This finding provides a promising, although unexpected, strategy for moving forward with phage treatments for vancomycin-resistant Enterococcus infections.