International Journal of Antimicrobial Agents

Sepsis is a global health problem. Patients in the Intensive Care Unit (ICU) are at risk of having sepsis because of their vulnerability and use of invasive medical devices. Emerging antimicrobial-resistance complicates treatment. Understanding bacterial profiles and antibiotic sensitivity patterns in the ICU plays an important role in managing sepsis, optimizing antimicrobial use, and improving patient outcomes. The aim of this study was to show bacterial profiles and antibiotic sensitivity patterns among patients who were admitted to the ICU at Mbeya Zonal Referral Hospital for 12 months. This was a prospective cross-sectional study among 187 sepsis-suspected patients. Data analysis was performed using SPSS Version 27. Categorical data were summarized by frequency and percentage. Fishers exact test, chi-square test, and modified Poisson regression were used to show the association between patients clinical variables and culture positivity at a 95% CI. Statistical significance was set at a p-value < 0.05. Out of 187 samples, 41.7% were culture positive. Gram-negative bacteria were commonly isolated (65.4%, with Klebsiella pneumoniae and Escherichia coli being commonly isolated. Commonly isolated Gram-positive bacteria were Coagulase-negative Staphylococcus species (19%). 100% of gram-positive bacteria and 96% of gram-negative bacteria were Multi-Drug Resistant (MDR), respectively. In multivariable analysis, patients who were intubated and mechanically ventilated (aPR = 2.208, 95% CI: 1.133-4.305, p = 0.020) and post-laparotomy patients (aPR = 3.241,95% CI: 1.320-7.958, p = 0.010) independently had a higher proportion of Gram-negative bacteria. The study reveals a high level of resistance to commonly used antimicrobials in our setting, necessitating strengthening of the antimicrobial stewardship program and routine surveillance of antimicrobial resistance patterns.

Purpose: To compare the efficacy and safety of intravenous cefazolin versus antistaphylococcal penicillins for the treatment of MSSA bacteremia in adults using evidence exclusively from randomized controlled trials. Methods: We searched 5 databases for RCTs comparing definitive intravenous cefazolin with ASPs (oxacillin, cloxacillin, flucloxacillin, nafcillin) in adults with MSSA bacteremia. Primary outcomes were 90-day all-cause mortality and acute kidney injury (AKI). Secondary outcomes included adverse event-related treatment discontinuation and persistent bacteremia (>72h). Dichotomous outcomes were synthesized as risk ratios (RRs) with 95% confidence intervals (CIs) using random-effects models with Paule-Mandel estimation and Hartung-Knapp-Sidik-Jonkman inference. Fixed-effect Mantel-Haenszel models were performed as sensitivity analyses. Results: Two RCTs randomized 1,656 participants (SNAP, n = 1,341; CloCeBa, n = 315), of whom 1,579 contributed to the 90-day mortality analysis. There was no statistically significant difference in 90-day mortality (RR 0.90, 95% CI 0.57-1.41; I2 = 0%). Both trials favoured cefazolin for acute kidney injury, but the random-effects estimate was highly imprecise (RR 0.26, 95% CI 0.00-939,970.59; I2 = 81.7%). Treatment discontinuation also favoured cefazolin directionally, although the random-effects estimate was imprecise (RR 0.24, 95% CI 0.00-24.41; I2 = 36.2%). Microbiological outcomes were synthesized narratively because definitions and assessment time points differed between trials. Conclusion: Randomized evidence supports cefazolin as a potential definitive treatment option when adequate source control, appropriate antimicrobial dosing, and clinical monitoring can be achieved. However, the limited number of trials and imprecision in pooled estimates warrant cautious interpretation.

Nontuberculous mycobacterial (NTM) infections are a scourge that affect growing patient populations due to the rise of risk factors associated with these opportunistic pathogens. Cure rates are unacceptably low despite intensive multidrug and multi-year therapy. The issue of poor drug exposure relative to inferior potency of repurposed antibiotics against NTM pathogens is broadly recognized as a major factor underlying dismal success rates. Yet, a quantitative and systematic evaluation of probabilities of pharmacokinetic-pharmacodynamic (PK-PD) target attainment (PTA) is lacking. Here, we leveraged published population PK models and minimum inhibitory concentration distributions across large patient populations to generate PTAs for standard of care antibiotics used in the treatment of NTM infections. PTAs of tuberculosis drugs were included in our analysis as a baseline since tuberculosis cure rates are excellent compared to NTM diseases. We found that PK-PD target attainment for NTM was low overall and that PTAs were generally consistent with reported clinical outcomes. Specifically, drugs for which genetic resistance is associated with worse outcome showed favorable PTAs, consistent with their contribution to cure. These include macrolides for M. abscessus and the M. avium complex (MAC), and rifampicin for M. kansasii. Bedaquiline emerged as a promising option against M. abscessus and MAC, and clofazimine against the latter, consistent with recent clinical reports. Omadacycline PTAs predict improved efficacy compared to tigecycline for patients with M. abscessus and suggest clinical utility for MAC. As is common practice for antibacterials, PTA considerations could inform NTM treatment guidelines and help select drug combinations in future trials.

Purpose: Vancomycin-resistant Gram-positive organisms represent a potential therapeutic challenge in endophthalmitis. To evaluate alternative treatment options, the FDA-approved oxazolidinones linezolid (LZD) and tedizolid (TZD) were tested against a collection of Gram-positive bacterial endophthalmitis isolates. Methods: Minimum inhibitory concentrations (MICs) were determined using epsilometers (Etest strips) for coagulase negative staphylococci (CoNS, n=20), Staphylococcus aureus (n=18), Bacillus species (n=10), Enterococcus species (n=5), and Streptococcus pneumoniae (n=1). Available CLSI and EUCAST breakpoints were applied to determine susceptibility. Results: TZD exhibited a >5-fold reduction in median MIC compared with LZD across all organisms tested (p<0.0001). MIC90 values for CoNS were 2.0 /ml for LZD and 0.25 /ml for TZD. For S. aureus, MIC90 values were 1.5 /ml (LZD) and 0.19 /ml (TZD). For Bacillus spp., MIC90 values were 1.0 /ml (LZD) and 0.25 /ml (TZD). Among Enterococcus species, the MIC range was 0.5-4.0 /ml (LZD) and 0.064-0.75 /ml (TDZ). The single S. pneumoniae strain had a MIC of 0.5 for LZD and 0.064 for TZD. All isolates were susceptible to TZD. One Enterococcus isolate was non-susceptible to LZD; the remaining isolates were susceptible. Conclusions: LZD and TZD demonstrated in vitro activity against Gram-positive bacterial endophthalmitis isolates, with TZD displaying consistently lower MICs than LZD. These findings suggest that oxazolidinones may represent potential alternatives when vancomycin cannot be used, including infections caused by vancomycin-resistant Gram-positive organisms. Given their excellent oral bioavailability, favorable safety profile, and reported anti-virulence effects in certain pathogens, further evaluation of oxazolidinones for the treatment of intraocular infections is warranted.

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is one the most common cause of post-surgical infections in Malawi and poses a significant public health challenge due to resistance to commonly used antibiotics. We isolated and evaluated the stability and lytic activity of a MRSA-specific bacteriophage (Staphylophage) from Mzuzu Central hospital (MZCH) sewage against MRSA strains isolated from surgical wards. MethodsA prospective in vitro experimental study was conducted using 56 pus swabs collected from post-surgical patients at Mzuzu Central Hospital (MZCH), Malawi. Standard microbiological methods and VITEK analysis were used for bacterial isolation, identification and antimicrobial susceptibility testing of Staphylococcus aureus and MRSA according to the 2024 EUCAST guidelines. A lytic Staphylophage was isolated and purified from sewage wastewater using filtration, enrichment, and double-layer agar techniques. The purified Staphylophage was evaluated for its lytic activity through host range testing and stability under ultraviolet (UV) exposure (up to 60 minutes), different pH levels (2-12), and temperatures (4{degrees}C, -20{degrees}C, and -80{degrees}C). ResultsOut of 56 bacterial isolates, 18 (32.1%) were S. aureus, of which 11 (61.1%) were MRSA. The isolated Staphylophage showed lytic activity against 87% of Staphylococcus species tested. The phage remained stable at temperatures between -80{degrees}C and 4{degrees}C and across a pH range of 2- 12. It also retained viability after UV exposure for up to 15 minutes, although a reduction in phage titre was observed after 30 minutes. ConclusionsA lytic Staphylophage isolated from hospital sewage at MZCH demonstrated activity against Staphylococcus species, including MRSA strains from post-surgical wound infections. These findings illustrate the feasibility of generating candidate phages for alternative therapeutic approaches in a central hospital setting in Malawi.

Background: Bovine respiratory disease (BRD) is a major cause of antimicrobial use in cattle, raising concerns about antimicrobial resistance (AMR). This systematic review estimated pooled AMR proportions in BRD pathogens: Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni, and assessed temporal and geographic trends in resistance. Methods: Five antimicrobials commonly used for BRD treatment were evaluated: penicillin G (PEN), tetracycline (TET), florfenicol (FLO), tulathromycin (TUL), and enrofloxacin (ENR). Following PRISMA guidelines, 1,097 records were screened and 24 studies met inclusion criteria. Study quality and risk of bias were assessed, and random-effects meta-analyses estimated pooled proportions of resistant isolates by antimicrobial, continent and period. Results: A total of 13,949 bacterial isolates were analysed including P. multocida (5,615), M. haemolytica (5,585), and H. somni (2,749). TET resistance was highest across all pathogens (12-30%), followed by TUL (6-11%), PEN (4-12%), FLO (0.5-1.6%) and ENR (0.2-1.1%). TET resistance in M. haemolytica and P. multocida, and FLO resistance in P. multocida were significantly more frequent in North America than in Europe (p[&le;]0.05). TUL resistance increased significantly in P. multocida after 2013 (p=0.038), with similar non significant trends in M. haemolytica and H. somni. FLO resistance decreased significantly in H. somni after 2013 (p=0.013). Egger's test identified significant funnel plot asymmetry for ENR resistance in H. somni and PEN resistance in M. haemolytica, suggesting possible small study effects. Conclusion: These results offer insights into distribution of phenotypic resistance across pathogens and regions, informing BRD antimicrobial treatment guidelines and One-Health antimicrobial stewardship aimed at preserving the effectiveness of medically important antimicrobials.

Nicotinamide riboside (NR), an endogenous precursor to the essential coenzyme nicotinamide adenine dinucleotide (NAD+), is characterized as safe and effective for longitudinally elevating NAD+ in blood and tissues, when administered orally. Interest in alternative routes of administration of NR has increased in recent years and led to the development of pharmaceutical-grade NR for intravenous and injectable administration. To evaluate the safety and efficacy of repeat daily injections of NR, an open-label, pilot, trial was initiated. Utilizing a 2x2 parallel study design, 39 study participants were randomized to intramuscular (IM) or subcutaneous (SC) injection administration, and 50 or 100 mg of NR, for 3 consecutive days, followed by a 7-day washout (50 mg IM, n=7; 100 mg IM, n=11; 50 mg SC, n=11; and 100 mg SC, n=10). To assess the primary outcome of safety, vitals, blood biomarkers, and adverse event monitoring were employed. Additional assessments included NAD+ pharmacokinetics and subjective participant-reported outcomes. Daily injections of NR were well tolerated and did not result in any unexpected adverse events or experiences. Pain and muscle soreness/tightness more than two minutes after the injection were reported by 44% and 41% of the participants, respectively, regardless of the route of administration or dose. Significant heterogeneity of pharmacokinetic parameters for NAD+ augmentation of whole blood was observed, however an average of the daily percentage increases in NAD+ was consistent across treatment groups, resulting in 9.51, 9.97, 7.83, and 9.05% for 50 mg IM, 100 mg IM, 50 mg SC, and 100 mg SC, respectively. Exploratory participant-reported outcomes suggest potential benefits on fatigue and sleep, with mixed effects on global physical health. Repeat daily injections of NR were well tolerated, and findings warrant investigation in larger, powered, placebo-controlled trials.

BackgroundSevere community-acquired pneumonia (CAP) remains a leading cause of mortality in children under five. The PediCAP trial evaluated oral step-down therapy using dispersible amoxicillin or amoxicillin/clavulanate tablets in African children hospitalised with severe CAP. Dispersible tablet formulations are preferred in children; however, pharmacokinetic data for oral amoxicillin/clavulanate in paediatric populations remain limited. We characterised the pharmacokinetics of 4:1, 7:1, and 14:1 dispersible amoxicillin/clavulanate tablets in children enrolled in the PediCAP trial and predicted target attainment under different dosing schemes. MethodsChildren were randomised within 24 hours of starting intravenous antibiotics to oral step-down therapy with weight-banded dosing of twice-daily amoxicillin/clavulanate (4:1, 7:1, or 14:1). Plasma concentrations were quantified following intensive sampling and analysed using nonlinear mixed-effects modelling with allometric scaling and postmenstrual age-dependent clearance maturation. Pharmacodynamic indices included %fT>MIC for amoxicillin and %fT>Ct for clavulanate. ResultsA total of 157 children (median [range] age, 12 [2-70] months; weight, 8.4 [4.0-22.0] kg) contributed 707 paired concentrations. Amoxicillin was described by a two-compartment model and clavulanate by a one-compartment model, both with sequential zero-and first-order absorption. Typical clearance for an 8-kg individual at full maturation was 11.8L/h for amoxicillin and 6.1L/h for clavulanate. Pharmacokinetics were similar between the formulation ratios. Weight-banded dosing achieved balanced exposures across weight groups. Amoxicillin achieved 40%fT>MIC for MICs[&le;]2mg/L. A proposed clavulanate target of 20%fT>0.5mg/L was achieved in most children even at the lowest amoxicillin/clavulanate ratio. ConclusionWeight-banded dosing using dispersible amoxicillin/clavulanate tablets provide consistent exposure profiles in African children with severe CAP. SUMMARYPopulation pharmacokinetic modelling of dispersible amoxicillin/clavulanate tablets (4:1, 7:1, 14:1) in 157 African children with severe pneumonia showed weight-banded dosing achieved consistent and adequate amoxicillin and clavulanate exposures across formulations.

Antimicrobial resistance is a global One Health threat connecting antimicrobial use in human health, animal husbandry, and companion animal health with concern for persistence in environmental reservoirs. Complicating this threat is the gap that exists in our understanding of the intersection of antimicrobial resistance among humans and our companion and food production animals. This study applies a visual and statistical approach to further understand antimicrobial resistance characteristics and relatedness of Escherichia coli found in humans, dogs and cattle. The primary study collection included third-generation cephem resistant (3GCR) E. coli isolates recovered from human, dog, and cattle gastrointestinal specimens and secondarily human and dog isolates recovered from infection sources, primarily urinary tract infections. We previously reported on the transferable gene targets encoding for 3GCR in colonizing isolates and here further identified the familial-like clonal group of each resistant isolate using a novel clonotype diagnostic (septatyping). Together, this approach identified distinct genetic signatures among these 3GCR isolates, many of which are peculiar to their respective host species. We found that the overlap measured by the correlation in abundance of shared clonotypes of resistant E. coli among hosts revealed statistically greater similarity between dogs and humans than between cattle and humans. Yet, the reservoir of AMR genes was highest in cattle and secondarily dogs. While these findings demonstrate that clonotypes of 3GCR E. coli in humans, dogs and cattle display significant host specificity, transient colonization from a host enriched with resistant strains may still pose considerable risk of horizontal transfer of resistance genes between hosts living in proximity to each other.

Background Metoclopramide is prescribed during pregnancy to treat nausea and vomiting. Despite its widespread application, there is potential for peripartum maternal metoclopramide dosing to induce extrapyramidal symptoms (EPS) in the newborn due to residual pediatric drug levels at birth. Here, a physiology-based pharmacokinetic model, including pregnancy-related changes and placental transfer values, was established and verified for metoclopramide. Human placenta cotyledon perfusion experiments were conducted to estimate placental transfer of metoclopramide. Transfer parameters were incorporated in a Simcyp PBPK model to enable predictions of fetal plasma and brain concentrations at different gestational ages (GA). Simulations were performed for the pre-cesarian section dosing of 10 milligram (mg) intravenously (IV, single dose), after which predicted fetal brain concentrations were used to calculate dopamine (D2) receptor occupancy. Findings & Conclusions Human ex vivo placental perfusion data were successfully generated and integrated into a pregnancy-specific physiology-based pharmacokinetic model to characterize maternal, fetal, and fetal brain exposure to metoclopramide. The model adequately predicted pharmacokinetics in healthy volunteers and pregnant individuals. Simulations of 10 mg IV dosing show mean metoclopramide peak concentrations of 47.0, 39.5 and 37.9 ng/mL in the fetal plasma at 24, 32 and 40 weeks GA, respectively. Residual drug levels immediately after birth were assumed to be equal to predicted fetal plasma levels. Newborn brain concentrations were predicted to be of the same order of magnitude as maternal plasma levels, with maternal plasma-to-fetal brain ratios of 1:0.98, 1:0.76 and 1:0.65 at GA 24, 32 and 40 weeks, highlighting evident distribution to the newborn central nervous system. Average newborn brain D2 receptor occupancy, which was used as a surrogate pharmacodynamic marker for EPS, remained below the 80% threshold for all simulated GAs. However, predicted population variability indicated that for a small but clinically relevant subset of newborns (~ 5% at 24 weeks and ~1% at 32 weeks GA, respectively), the 80% D2-receptor occupancy could be exceeded under standard dosing regimens, indicative of EPS risk.

Predicted probabilities of antibiotic susceptibility to known or suspected pathogens can be used to support antibiotic selection. Patient demographic, clinical, and prior microbiologic history can be used to generate location-specific prediction models. For three Canadian tertiary care institutions we fit and evaluated models for predicting Gram-negative antibiotic susceptibilities to common antimicrobial agents based on previously established model structures. A web-based application was developed to permit visualization of antibiotic susceptibility predictions and support antibiotic decision-making.

Model averaging combines the predictions of several population pharmacokinetic models to support model-informed precision dosing, but how to select ensemble models remains unexplored. Using tacrolimus as a case study, we first evaluated all possible ensembles of 27 models in 37 kidney and liver transplant recipients with full pharmacokinetic profiles at occasions 1 and 5 and trough concentrations at occasions 2, 3 and 4. Models were weighted by individual objective function value. Predictive performance for the occasion 5 area under the curve was assessed with individual parameters estimated from the occasion 5 trough concentration or from occasion 1 to 4 observations. Then, seven ensembles, selected a priori from relevance and external evaluation scores or as the best-performing ensembles previously identified, were compared across ten sets of observations, from a single trough concentration to dense sampling. Mean imprecision per ensemble size reached a plateau beyond 3-4 models. The best ensembles depended on the set of observations, comprising three models with the occasion 5 trough concentration and seven or eight models with occasions 1 to 4 observations. Across all sets, the ensemble optimised on the occasion 5 trough concentration was among the most precise, and score-based ensembles remained consistently precise, whereas the ensemble optimised on occasions 1 to 4 generalised poorly. Only a limited sampling strategy at occasion 5 kept imprecision below 20% for all ensembles. The plateau effect generalised to infliximab and cefepime. Ensemble composition matters more than ensemble size. Model averaging should rely on well-chosen ensembles rather than all available models.

Invasive candidiasis has become more common in recent decades, particularly within ICUs. Identifying specific Candida spp., and testing their sensitivity to antifungal drugs is crucial for effective treatment that helps healthcare providers to detect potential treatment challenges early. This study aimed to identify Candida spp. at their spp. level present in blood, assess their susceptibility to antifungal agents, and apply a random forest classifier to predict the best antifungal drug for a given species. The isolates were classified at the species complex level through MALDI-TOF MS. The strains' susceptibility to antifungal agents such as AMB, FLZ, VOZ, ITZ, POZ, CAS, MFN, and ANF was assessed using CLSI guidelines. Out of the 354 Candida spp. isolated from blood, C. utilis was found to be the predominant species, followed by C. tropicalis, and C. albicans. This study demonstrated that MFN and ANF exhibited high potency, with an impressive MIC90 of 0.12 {micro}g/mL against all isolates, surpassing CAS, which had a slightly higher overall MIC90 of 0.25 {micro}g/mL. FLZ exhibited the highest MIC90 value among the azoles at 16 {micro}g/mL, while VOZ, ITZ, and POZ all had MIC90 values of 0.5 {micro}g/mL. AMB MIC90 values were 2 {micro}g/mL against all isolated Candida species. The Random Forest AI/ML model showed perfect overall prediction, with the actual and predicted best antifungal drugs matching for all fungal species. This study is particularly essential because rare Candida spp. becoming more common and exhibiting higher MICs to AMB and FLZ and required suitable remedies for controlling the infection.

Background. Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events in almost any organ. While myocarditis has received the most attention, data on pericardial disease with ICI use are limited. We examined pericardial adverse event reporting with nine ICIs using the FDA Adverse Event Reporting System (FAERS). Methods. We combined legacy AERS and current FAERS quarterly files from January 2011 to June 2026 into 18,629,240 unique cases, deduplicated by case number, and removed cases the FDA had listed as deleted. ICI exposure was identified from generic names, brand names, development code names and the active-ingredient field. Pericardial events were defined by seven MedDRA preferred terms. We estimated reporting odds ratios (ROR), proportional reporting ratios (PRR), Bayesian information components (IC) and empirical Bayes geometric means (EBGM). We also examined myocarditis co-reporting, time trends, a comparison with other antineoplastic agents, a MedDRA query-based outcome, and 14 alternative definitions. Results. The analysis included 18,514,045 cases: 277,434 involved an ICI, 34,792 carried a pericardial term, and 1,680 had both. Pericardial events were reported disproportionately with ICIs (ROR 3.35 (95% CI 3.19 to 3.52); PRR 3.34; IC025 1.62). Eight of nine agents had a ROR above 1 (3.32 to 5.63). Among the most frequently reported terms, estimates were highest for cardiac tamponade (5.59 (95% CI 4.98 to 6.28)), followed by pericardial effusion (3.83 (95% CI 3.60 to 4.07)) and pericarditis (2.09 (95% CI 1.89 to 2.31)). After removing cases that also reported myocarditis, the ROR was 3.13 (95% CI 2.98 to 3.30). Most sensitivity analyses gave similar estimates (ROR 3.13 to 3.47); defining exposure by generic drug names alone, which identified only 44% of exposed cases, gave 3.99. Compared with cases naming other L01 antineoplastic agents, the ROR was 1.13 (95% CI 1.08 to 1.19): 1.28 (95% CI 1.20 to 1.36) for ICI-only cases and 0.96 (95% CI 0.89 to 1.04) when another antineoplastic was also named. The ICI-specific reporting odds ratio fell each quarter (odds ratio 0.977 per quarter, 95% CI 0.973 to 0.980). Conclusions. In FAERS, pericardial events were reported more often with ICIs than with other drugs across most agents and terms; however, incidence and causation cannot be determined. The excess over other antineoplastic agents was small, and reporting disproportionality declined over time. These findings support clinical awareness of pericardial disease in patients receiving ICIs and warrant study in data that can measure incidence.

Rationale: Tuberculosis preventive therapy (TPT) is essential for global tuberculosis control, yet estimated coverage remains well below global targets. Current World Health Organization (WHO)-recommended regimens require 1-9 months of treatment and are associated with suboptimal completion rates. Long-acting injectable (LAI) formulations offer the potential to improve TPT uptake and completion, with ideal products providing "one-and-done" options via a single administration. Sorfequiline, a second-generation diarylquinoline with superior potency over bedaquiline and lower QT prolongation risk, is a promising candidate for LAI TPT.

Objective: To test the hypothesis that selected SIRS and SOFA criteria measured at ICU admission have divergent associations with (1) the development of new culture-confirmed infections and (2) early empiric broad-spectrum antibiotic receipt in critically ill patients with cirrhosis. Design: Retrospective, observational study using electronic health record (EHR) data. Setting: Both community and academic ICUs within a five-hospital health system between July 2017 and December 2025. Subjects: Adult patients >18 years of age diagnosed with cirrhosis admitted to the ICU within 96 hours of hospital admission. Patients transferred from outside facilities and those with positive cultures collected >24 hours before ICU admission were excluded. Interventions: None. Measurements: Multivariable logistic regression tested the association of the most aberrant values in nine SIRS/SOFA vital sign and laboratory parameters measured during the 24 hours prior to ICU admission with (1) the development a newly positive culture collected during the 24 hours before through the 96 hours after ICU admission and (2) receipt of broad-spectrum antibiotics during the 24 hours before through the 24 hours after ICU admission. Main Results: The presence of hyperthermia, hypothermia, hypoxia, or hypotension at ICU admission was associated with both culture positivity and antibiotic receipt. The presence of leukocytosis was associated with antibiotic receipt but not culture positivity. Among patients in the 21.6% of encounters with newly positive cultures, normothermia and normal WBC were common (respectively present in 97.2% and 77.5% of encounters) and associated with antibiotic omission at ICU admission despite the subsequent development culture positivity. Conclusions: Traditional physiologic markers of infection are often absent in critically ill patients with cirrhosis who develop new culture-confirmed infections at ICU admission, possibly contributing to delayed antibiotics. There may be opportunities to improve antibiotic delivery and stewardship at ICU admission in this high-risk population.

BackgroundFebrile neutropenia requires rapid empirical antibiotic therapy, with regimen selection shaped by local prescribing practice and pathogen patterns. We described starting treatment, later drug changes, microbiological findings, and inpatient outcomes. MethodsThis ambispective cohort comprised 96 episodes from 90 patients admitted to a tertiary-level teaching hospital. Treatment and outcome analyses used each episode as the unit of observation. Recorded variables included the starting antibiotics, later regimen modification, microbiology, hospitalization length, invasive fungal infection (IFI) as captured in study records, and disposition. Comparisons based on escalation status were exploratory. ResultCefoperazone-sulbactam appeared in 62/96 initial regimens (64.6%), amikacin in 42 (43.8%), teicoplanin in 28 (29.2%), and meropenem in 14 (14.6%). Eighteen episodes (18.8%) required a change that broadened or substituted antibacterial therapy. Among 31 microbiologically documented infections, 22 (71.0%) yielded Gram-negative organisms and 9 (29.0%) were polymicrobial. Median length of admission was 18.5 days in the escalation group and 9 days in the remainder (p<0.001). Mortality was 27.8% (5/18) with escalation and 5.1% (4/78) without it (p=0.011), with nine inhospital deaths overall (9.4%). ConclusionAntibacterial management differed within this cohort, with treatment escalation required in 18 of 96 episodes. Gram-negative organisms comprised most microbiologically confirmed infections. Escalation marked a clinically complex course with prolonged hospitalization and greater observed mortality; the observational design does not establish comparative efficacy or causation.

Screening of the open-access CRESTdb small-molecule library identified the imidazothiazole carboxamide sCQG200 (1) as an initial hit, with activity against H37Rv and Erdman Mycobacterium tuberculosis strains in cholesterol-containing medium (MIC90= 6.88 uM and 4.48 uM, respectively) and against intracellular Mtb (EC50= 3.80 uM). sCQG200 retained activity against drug-resistant Mtb strains, including clinical MDR/XDR isolates. SAR optimization led to analogs 21 and 24 with substantially improved antimycobacterial potency. Mouse pharmacokinetic studies following oral and intravenous administration showed 62.1% and 29.5% oral bioavailability for 21 and 24, respectively. This structurally differentiated chemotype provides a promising starting point for further optimization as antitubercular agent.

Background: Half of US children are prescribed an antibiotic by age 2. Maternal education and socio-economic factors influence prescribing but the role of other factors, such as age of solid food introduction is unknown. Objectives: We assessed risk factors for time to first antibiotic use between birth to age 2 to identify modifiable drivers of antibiotic use. Methods: We analyzed interviews from mothers of 1032 children participating in the mother-child Center for Oral Health Research in Appalachia cohort 2 between 2011 and 2017. The cohort enrolled healthy, English-speaking, pregnant White women > 18 years with singleton pregnancies. We used time-to-event analyses and a Cox Proportional Hazards model to describe and estimate hazard ratios (HRs) for time to first antibiotic. Results: By age 2, 78% of children received at least one antibiotic (median age at first antibiotic: 12.5 months). Over half (58%) of antibiotics prescribed were for ear infections. After adjustment for household income and birth quarter as fixed variables, time of solid food introduction (aHR: 4.75; 95% CI: 3.19, 7.07), time of first ear infection (aHR: 3.28; 95% CI: 2.58,4.17), and time of first illness (aHR: 4.60; 95% CI: 3.32,6.36) were significantly associated with time of first antibiotic use. Conclusions: Earlier time of solid food introduction was associated with earlier antibiotic use. Childhood illnesses, especially ear infections, also strongly influence antibiotic initiation. These modifiable factors offer targets to reduce unnecessary early antibiotic use.

Objectives- Among clinical methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) strains, we sought to determine the prevalence of {beta}-lactam-{beta}-lactamase inhibitor (BLBLI) susceptibility, and its association with oxacillin susceptibility, genotypic factors, and patient characteristics. Methods- Clinical MRSA BSI strains were tested for susceptibility to penicillin-clavulanate by Etest (n=117, 36% of the dataset) and to oxacillin by disk diffusion assay (n=328, 100%). Penicillin-clavulanate susceptibility was defined as MIC [&le;]2mg/L and oxacillin disk susceptibility as an inhibition zone > 6mm. All strains were whole-genome sequenced, and alleles of mecA annotated. The sensitivity and specificity of the oxacillin disk to predict penicillin-clavulanate 'susceptibility' were assessed. Clinical and genomic associations with BLBLI 'susceptibility' were assessed by calculating odds-ratios (OR). Results -We found 73/117 (62%) and 205/328 (62%) strains to be 'susceptible' to penicillin-clavulanate and oxacillin disk, respectively. Oxacillin disk susceptibility and penicillin-clavulanate susceptibility were highly correlated (sensitivity 97.3% and specificity 95.5%). We therefore used oxacillin disk susceptibility as a proxy for penicillin-clavulanate susceptibility. Comparative genomics of the mecA gene uncovered 8 alleles. The oxacillin disk 'susceptible' phenotype was associated with specific mecA alleles, community-associated MRSA sequence-types (OR 72.8, 95%CI 35.4-162), community acquisition of infection (OR 2.09, 95% CI 1.03-4.27), lower Charlson Comorbidity Index (OR 0.90, 95% CI 0.82-0.98) and SOFA (sequential organ failure assessment) scores at presentation (OR 0.88, 95% CI 0.79-0.98). Conclusion - BLBLI 'susceptibility' is common among MRSA strains and is strongly associated with the strain genotype. Infections caused by BLBLI 'susceptible' strains are associated with specific patients' characteristics, namely younger age, fewer comorbidities, acquisition in the community and milder presentations.