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This study elucidates the in vivo genetic mechanisms contributing to the emerging resistance to carbapenem in Shewanella algae through a lens of adaptive microbial evolution. Leveraging PacBio amplification-free sequencing, we tracked the evolution of β-lactam resistance in clinical isolates from a persistent S. algae bacteremia case amidst antimicrobial therapy. Our investigation spotlighted a recurrent G547W mutation in the sensor histidine kinase (pdsS), which was associated with the overexpression of an OmpA-like protein (pdsO) within a proteobacteria-specific sortase system. Intriguingly, we observed a recurrent switch between wild-type and G547W alleles, revealing an adaptive expansion and contraction of underlying cell subpopulations in response to β-lactam exposure. Comparative transcriptome analyses further demonstrated the overexpression of genes pivotal for membrane integrity, biofilm formation, immune evasion, and β-lactamase activation in resistant samples. This underscores the pre-existence of resistant cells at minuscule frequencies even without antibiotic pressure, potentially explaining the within-host emergence of resistance during antibiotic treatments. Our findings provide pivotal insights into the dynamic genetic adaptations of S. algae under therapeutic pressures, unmasking intricate resistance mechanisms and highlighting the critical role of subpopulation dynamics in treatment outcomes. [ABSTRACT FROM AUTHOR]

Background: A simple suspension method, where solid formulations are disintegrated and suspended by being soaked in warm water followed by tube administration, is widely used, especially for elderly patients with dysphagia in Japanese clinical settings. However, there is insufficient information on drug stability in the simple co-suspension of multiple formulations especially including acidic or alkaline ones. The influence of occasional prolonged soakage on drug stability is also of concern. In this study, the chemical stability of typical β-lactam antibiotics, amoxicillin, and cefcapene pivoxil hydrochloride, was investigated in simple co-suspensions with magnesium oxide (MgO), which is frequently used as an alkaline laxative for the elderly. Methods: Amoxicillin (capsule) or cefcapene pivoxil hydrochloride (tablet) was placed with or without MgO (tablet) in a centrifuge tube containing warm water (55 °C). The tube was allowed to stand for 10 min or 5 h at room temperature and simple suspensions were prepared. The suspensions were then treated with large amounts of solvents and neutralized using a weakly acidic cation exchange resin. The resulting solutions were analyzed by high-performance liquid chromatography. The degradation products were identified by mass spectrometry and nuclear magnetic resonance spectroscopy. Results: Amoxicillin was found to be partially degraded to amoxicilloic acid and amoxicillin diketopiperazine by the co-suspension with MgO. The degree of degradation increased with the prolonged soaking. The recovery rates of cefcapene pivoxil decreased due to the poor solubility in the co-suspensions with MgO and no degradation product of the drug was observed. Conclusions: Amoxicillin and MgO should be independently suspended because of the chemical instability of amoxicillin. This study has also indicated there is a degradation risk after prolonged soaking. It should be noted that the poor water solubility of cefcapene pivoxil under alkaline conditions may affect the absorption process as well as tube passability. [ABSTRACT FROM AUTHOR]

Background: Novel β-lactam antibiotics as well as other kinds of antibiotics have been used to treat complicated urinary tract infections (cUTIs); however, their efficacy and safety remain controversial. Objective: We conducted a systematic review with meta-analysis to explore the efficacy and safety of novel β-lactam antibiotics versus other antibiotics against cUTIs. Methods: PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched systematically from inception through 15 March 2024 for clinical trials comparing novel β-lactam antibiotics with other antibiotics for treatment of cUTIs. Random-effects models were used to evaluate the impact of treatment on the risk ratio (RR) of clinical response, microbiologic response, adverse effects (AEs), serious adverse effects (SAEs). The quality of evidence was evaluated with the Cochrane Risk of Bias assessment tool. The review was registered in INPLASY (INPLASY202440054). Results: Ten randomized controlled trials involving 5, 925 patients met our inclusion criteria. Our meta-analysis revealed that there was no significant difference in overall clinical response (RR = 1.02), AEs (RR = 1.07), SAEs (RR = 1.20) between novel β-lactam antibiotics groups and other antibiotics groups. However, a significant difference was found in a subgroup of clinical cure rates at the end of treatment between novel β-lactam antibiotics groups and carbapenems groups, with low heterogeneity (RR = 1.02). A significant difference was observed in microbiologic response (RR = 1.11). Subgroup analysis revealed a significant difference in microbiologic response between novel BBL/BLS groups and carbapenems groups (RR = 1.13, I² = 21%, P = 0.005). Differences was observed between novel BBL/BLS groups and piperacillin/tazobactam sodium groups (RR = 1.21, I² = 70%, P = 0.02). Similar results were obtained from subgroup analysis of the difference in microbiologic response between novel β-lactam antibiotics groups and ertapenem groups (RR = 0.92, I² = 0, P = 0.01). Conclusion: Novel β-lactam antibiotics had similar overall clinical cure, AEs, SAE, to other antibiotics in the treatment of cUTIs. However, novel β-lactam antibiotics demonstrated superior clinical cure rates compared to carbapenems in a subgroup analysis, and exhibited better microbiologic response than other antibiotics. [ABSTRACT FROM AUTHOR]

Objective To investigate the clinical features of drug eruptions and the most common causative drugs in inpatients in order to provide a reference for the diagnosis and the treatment of drug eruptions. Methods We retrospectively analyzed the clinical data of inpatients with drug eruptions at the First Affiliated Hospital of Shihezi University from April 2019 to December 2023. Results A total of 89 inpatients with drug eruptions, accounting for 2.90% of the total inpatients at the dermatology department during the same period, included 63 cases(70.79%) of mild drug eruptions(mainly the exanthematous eruptions) and 26 cases (29.21%) of severe drug eruptions (mainly SJS). The most common condition using allergenic drugs was infectious diseases (44 cases, 49.44%), while the majority of drug eruptions(63 cases, 70.79%) were caused by single drug. The top 3 allergenic drugs were antibiotics (33.33%), traditional Chinese medicine (26.98%) and antiepileptics (14.29%). The latency time of mild drug eruptions was shorter than that of severe drug eruptions (4.56 ± 6.14 days vs. 9.35 ± 11.33 days, t = 2.03, P = 0.025). High fever at the early stage was observed in 19.05% of patients with mild drug eruptions and 46.15% of patients with severe drug eruptions. The mean times of hospital stay were comparable between patients with mild drug eruptions and severe drug eruptions (9.02 ± 3.58 days). Systemic glucocorticoids were given to 46(51.69%) patients, including 4 cases of severe drug eruptions, two of each treated together with immunoglobulin and tumor necrosis factor (TNF) -α antagonist, respectively. No deaths were found during the follow-up. Conclusions Exanthematous eruption is the most common type of drug eruptions, while the common allergenic drugs are antibiotics, traditional Chinese medicines and antiepileptics. Large portion of patients with drug eruptions, especially severe cases, experience high fever at the early stage. However, hospitalization time does not diifer between patients with severe and mild drug eruptions. Early administration of sufficient glucocorticoids alone or in combination with other therapies can shorten the hospitalization time for severe drug eruptions. [ABSTRACT FROM AUTHOR]

Antibiotics are the super drugs that have revolutionized modern medicine by curing many infectious diseases caused by various microbes. They efficiently inhibit the growth and multiplication of the pathogenic microbes without causing adverse effects on the host. However, prescribing suboptimal antibiotic and overuse in agriculture and animal husbandry have led to the emergence of antimicrobial resistance, one of the most serious threats to global health at present. The efficacy of a new antibiotic is high when introduced; however, a small bacterial population attains resistance gradually and eventually survives. Understanding the mode of action of these miracle drugs, as well as their interaction with targets is very complex. However, it is necessary to fulfill the constant need for novel therapeutic alternatives to address the inevitable development of resistance. Therefore, considering the need of the hour, this article has been prepared to discuss the mode of action and recent advancements in the field of antibiotics. Efforts has also been made to highlight the current scenario of antimicrobial resistance and drug repurposing as a fast-track solution to combat the issue. [ABSTRACT FROM AUTHOR]

Abstract β-Lactam antibiotics are a class of antibiotics commonly used to treat bacterial infections. However, the effects of β-lactam antibiotics on term neonatal intestinal flora have not been fully elucidated. Hospitalized full-term newborns receiving β-lactam antibiotics formed the antibiotic group (n = 67), while those without antibiotic treatment comprised the non-antibiotic group (n = 47). A healthy group included healthy full-term newborns (n = 16). Stool samples were collected for 16 S rDNA sequencing to analyze gut microbiota variations. Further investigation was carried out within the β-lactam antibiotic group, exploring the effects of antibiotic use on the newborns’ gut microbiota in relation to the duration and type of antibiotic administration, delivery method, and feeding practices. The antibiotic group exhibited significant difference of microbial community composition compared to the other groups. Genera like Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas were enriched, while Escherichia-Shigella, Clostridium sensu stricto 1, Bifidobacterium, and Parabacteroides were reduced. Klebsiella negatively correlated with Escherichia-Shigella, positively with Enterobacter, while Escherichia-Shigella negatively correlated with Enterococcus and Streptococcus. Regardless of neonatal age, β-lactam antibiotics induced an elevated abundance of Klebsiella and Enterococcus. The impact on gut microbiota varied with the duration and type of antibiotic (cefotaxime or ampicillin/sulbactam). Compared to vaginal delivery, cesarean delivery after β-lactam treatment heightened the abundance of Klebsiella, Enterobacteriaceae_Unclassified, Lactobacillales_Unclassified, and Pectobacterium. Feeding patterns minimally influenced β-lactam-induced alterations. In conclusion, β-lactam antibiotic treatment for neonatal pneumonia and sepsis markedly disrupted intestinal microbiota, favoring Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas. The impact of β-lactam varied by duration, type, and delivery method, emphasizing heightened disruptions post-cesarean delivery.

Piperacillin/tazobactam is a well-known β-lactam antibiotic that has been used in clinical practice since 1993. The review presents the clinical and pharmacological characteristics of piperacillin-tazobactam, the results of clinical studies and determines place of this antibiotic in the treatment of patients with severe urinary tract infections and intraabdominal infections in the light of current data of pathogens’ susceptibility in the Russian Federation and current clinical guidelines.

β-Lactam antibiotics are a class of antibiotics commonly used to treat bacterial infections. However, the effects of β-lactam antibiotics on term neonatal intestinal flora have not been fully elucidated. Hospitalized full-term newborns receiving β-lactam antibiotics formed the antibiotic group (n = 67), while those without antibiotic treatment comprised the non-antibiotic group (n = 47). A healthy group included healthy full-term newborns (n = 16). Stool samples were collected for 16 S rDNA sequencing to analyze gut microbiota variations. Further investigation was carried out within the β-lactam antibiotic group, exploring the effects of antibiotic use on the newborns' gut microbiota in relation to the duration and type of antibiotic administration, delivery method, and feeding practices. The antibiotic group exhibited significant difference of microbial community composition compared to the other groups. Genera like Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas were enriched, while Escherichia-Shigella, Clostridium sensu stricto 1, Bifidobacterium, and Parabacteroides were reduced. Klebsiella negatively correlated with Escherichia-Shigella, positively with Enterobacter, while Escherichia-Shigella negatively correlated with Enterococcus and Streptococcus. Regardless of neonatal age, β-lactam antibiotics induced an elevated abundance of Klebsiella and Enterococcus. The impact on gut microbiota varied with the duration and type of antibiotic (cefotaxime or ampicillin/sulbactam). Compared to vaginal delivery, cesarean delivery after β-lactam treatment heightened the abundance of Klebsiella, Enterobacteriaceae_Unclassified, Lactobacillales_Unclassified, and Pectobacterium. Feeding patterns minimally influenced β-lactam-induced alterations. In conclusion, β-lactam antibiotic treatment for neonatal pneumonia and sepsis markedly disrupted intestinal microbiota, favoring Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas. The impact of β-lactam varied by duration, type, and delivery method, emphasizing heightened disruptions post-cesarean delivery. [ABSTRACT FROM AUTHOR]

Bacillus cereus sensu stricto is a foodborne pathogen that causes food poisoning. Their spore and biofilm-forming abilities persist in various environments and foods. This study investigated the prevalence, virulence, antibiotic resistance, and genetic diversity of B. cereus s. s. strains isolated from various food samples. Of 179 samples, 22.34% were positive for B. cereus s. s., with significantly high detection rates in milk products and raw chicken meat. Forty strains were isolated from positive samples. Matrix-assisted laser desorption ionization/time of flight mass spectrometry analysis revealed nine distinct clusters and multi-locus sequence typing revealed 34 sequence types including 23 novel sequences, demonstrating high genetic diversity among the isolates. PCR analysis revealed that all the strains contained at least one toxin gene, but none contained the cytK gene. Antibiotic resistance tests revealed that all isolates were classified as multidrug-resistant, with high resistance levels, particularly to β-lactam antibiotics and vancomycin, but were susceptible to gentamicin. All isolates showed variations in biofilm formation. This study highlights the significant public health risk due to B. cereus s. s. and underscores the need for stringent monitoring and control measures in food production to manage antimicrobial resistance and ensure food safety. [ABSTRACT FROM AUTHOR]

Nowadays, β-lactam antibiotics are one of the most consumed OTC (over-the-counter) medicines in the world. Its frequent use against several infectious diseases leads to the development of antibiotic resistance. Another unavoidable risk factor of β-lactam antibiotics is environmental toxicity. Numerous terrestrial as well as aquatic species have suffered due to the excessive use of these pharmaceuticals. In this present study, we have performed a toxicity assessment employing a novel in silico technique like quantitative structure–toxicity relationships (QSTRs) to explore toxicity against zebrafish (Danio rerio). We have developed single as well as inter-endpoint QSTR models for the β-lactam compounds to explore important structural attributes responsible for their toxicity, employing median lethal (LC50) and median teratogenic concentration (TC50) as the endpoints. We have shown how an inter-endpoint model can extrapolate unavailable endpoint values with the help of other available endpoint values. To verify the models' robustness, predictivity, and goodness-of-fit, several universally popular metrics for both internal and external validation were extensively employed in model validation (single endpoint models: r2 = 0.631 − 0.75, Q2F1 = 0.607 − 0.684; inter-endpoint models: r2 = 0.768 − 0.84, Q2F1 = 0.678 − 0.76). Again, these models were engaged in the prediction of these two responses for a true external set of β-lactam molecules without response values to prove the reproducibility of these models. [ABSTRACT FROM AUTHOR]

The persistent development of bacterial resistance to β-lactam antibiotics presents a serious risk to public health worldwide. The ability of metallo-β-lactamases (MBLs) to hydrolyze a wide range of β-lactam antibiotics and render them ineffective makes them a difficult challenge. The identification and design of clinically useful inhibitors against MBLs like Verona integron-encoded metallo-β-lactamase-2 (VIM-2) is still challenging. In this study, we examine the inhibitory capacity of peptides against VIM-2 of Pseudomonas aeruginosa. Deriving inspiration from earlier studies on arginine-rich peptides, we hypothesized that lysine repeats with similar nature may show comparable binding with VIM-2.We found that lysine repeats are much more stable than arginine repeats, and show comparable binding with VIM-2. Initially, we designed a library of peptides containing various combinations of lysine and arginine residues, with the sequence length of 30 amino acids. By means of computational modeling, Protein-Peptide docking and molecular dynamics simulations, we evaluated the stability and binding affinity of these peptides in complex with VIM-2. Peptides showing best binding with VIM-2 were subjected to optimization where length was reduced to 12 residues. This optimization was performed to reduce charge and potential toxicity, enhancing the translational prospects of the sequences. We observed that PolyKR (6) was found to be the lead candidate. We demonstrate that incorporation of KR repeats in peptide sequences can be of help in enhancing their binding affinity towards VIM-2. Further, wet-laboratory validation needs to be performed in order to study the interaction of the peptide with the VIM-2 MBL in detail. [ABSTRACT FROM AUTHOR]

Antibiotic treatment of Mycobacterium abscessus disease is toxic and poorly effective and lacks a firm evidence base. Dual β-lactam and β-lactam/β-lactamase inhibitor combinations may be interesting leads to improve treatment outcomes. To summarize the current preclinical studies on dual β-lactam and β-lactam/β-lactamase inhibitor combinations against M. abscessus. We performed a literature search using the National Center for Biotechnology Information's PubMed interface with additional snowball sampling. Select combinations of β-lactam antibiotics, as well as β-lactam/β-lactamase inhibitor combinations show promising in vitro activity and synergy against M. abscessus. β-Lactam antibiotics differ in their ability to reach and interfere with their targets and their resistance to the M. abscessus β-lactamase. The synergy is typically observed for combinations of β-lactam antibiotics or a β-lactam antibiotic with a β-lactamase inhibitor. No additional killing capacity was demonstrated in three-drug combinations of synergistic β-lactam antibiotics and a β-lactamase inhibitor. The efficacy of select dual β-lactam antibiotics and β-lactam/β-lactamase inhibitor combinations is retained in intracellular infection assays and mouse models, but no combination has a complete preclinical portfolio. Future clinical strategies should entail either dual β-lactam or β-lactam/β-lactamase inhibitor combinations. Imipenem-ceftaroline and an all-oral tebipenem-avibactam combination are promising leads but still require a complete preclinical portfolio, target product profiles as well as clinical trial confirmation. [ABSTRACT FROM AUTHOR]

Due to widespread overuse, pharmaceutical compounds, such as antibiotics, are becoming increasingly prevalent in greater concentrations in aquatic ecosystems. In this study, we investigated the capacity of the white-rot fungus, Coriolopsis gallica (a high-laccase-producing fungus), to biodegrade ampicillin under different cultivation conditions. The biodegradation of the antibiotic was confirmed using high-performance liquid chromatography, and its antibacterial activity was evaluated using the bacterial growth inhibition agar well diffusion method, with Escherichia coli as an ampicillin-sensitive test strain. C. gallica successfully eliminated ampicillin (50 mg L−1) after 6 days of incubation in a liquid medium. The best results were achieved with a 9-day-old fungal culture, which treated a high concentration (500 mg L−1) of ampicillin within 3 days. This higher antibiotic removal rate was concomitant with the maximum laccase production in the culture supernatant. Meanwhile, four consecutive doses of 500 mg L−1 of ampicillin were removed by the same fungal culture within 24 days. After that, the fungus failed to remove the antibiotic. The measurement of the ligninolytic enzyme activity showed that C. gallica laccase might participate in the bioremediation of ampicillin. [ABSTRACT FROM AUTHOR]

Monitoring plasma concentrations of β-lactam antibiotics is crucial, particularly in critically ill patients, where variations in concentrations can lead to treatment failure or adverse events. Standardized antimicrobial regimens may not be effective for all patients, especially in special groups with altered physiological parameters. Pharmacokinetic/pharmacodynamic (PK/PD) studies highlight the time-dependent antibacterial activity of these antibiotics, emphasizing the need for personalized dosing. Therapeutic drug monitoring (TDM) is essential, requiring rapid and accurate analytical methods for precise determination of drugs in biological material (typically plasma or serum). This study presents a novel capillary zone electrophoresis–tandem mass spectrometry (CZE-MS/MS) method designed for the simultaneous quantification of five penicillin antibiotics, two cephalosporins, one carbapenem, and two β-lactamase inhibitors in a single run. The method involves a simple sample pretreatment—precipitation with organic solvent—and has a run time of 20 min. Optimization of CZE separation conditions revealed that 20 mM ammonium hydrogen carbonate (NH4HCO3) serves as the optimal background electrolyte (BGE). Positive electrospray ionization (ESI) mode, with isopropyl alcohol (IP)/10 mM ammonium formate water solution (50/50, v/v) as the sheath liquid, was identified as the optimal condition for MS detection. Method validation according to the Food and Drug Administration (FDA) guideline for development of bioanalytical methods demonstrated satisfactory selectivity, linearity, recovery, robustness, and stability. The method's practicality was evaluated using the Blue Applicability Grade Index (BAGI), yielding a score of 77.5. Moreover, the greenness of the proposed method was evaluated by two commonly used metric tools—Analytical GREEnness (AGREE) and Green Analytical Procedure Index (GAPI). The developed CZE-MS/MS method offers a practical and reliable approach for quantifying a broad spectrum of β-lactam antibiotics in plasma. Its ability to simultaneously quantify multiple analytes in a single run, coupled with a straightforward sample pretreatment, positions it as a valuable and prospective tool for TDM in critically ill patients. [ABSTRACT FROM AUTHOR]

Invasive infections caused by Streptococcus pyogfenes (iGAS), commonly known as Group A Streptococcus, represent a significant public health concern due to their potential for rapid progression and life-threatening complications. Epidemiologically, invasive GAS infections exhibit a diverse global distribution, affecting individuals of all ages with varying predisposing factors. The pathogenesis of invasive GAS involves an array of virulence factors that contribute to tissue invasion, immune evasion, and systemic dissemination. In pediatrics, in the last few years, an increase in iGAS infections has been reported worldwide becoming a challenging disease to diagnose and treat promptly. This review highlights the current knowledge on pathogenesis, clinical presentations, and therapeutic approaches for iGAS in children. [ABSTRACT FROM AUTHOR]

The amino acid substitutions in Klebsiella pneumoniae carbapenemase 2 (KPC‐2) that have arisen in the clinic are observed to lead to the development of resistance to ceftazidime‐avibactam, a preferred treatment for KPC bearing Gram‐negative bacteria. Specific substitutions in the omega loop (R164‐D179) result in changes in the structure and function of the enzyme, leading to alterations in substrate specificity, decreased stability, and more recently observed, increased resistance to ceftazidime/avibactam. Using accelerated rare‐event sampling well‐tempered metadynamics simulations, we explored in detail the structural role of R164 and D179 variants that are described to confer ceftazidime/avibactam resistance. The buried conformation of D179 substitutions produce a pronounced structural disorder in the omega loop ‐ more than R164 mutants, where the crystallographic omega loop structure remains mostly intact. Our findings also reveal that the conformation of N170 plays an underappreciated role impacting drug binding and restricting deacylation. The results further support the hypothesis that KPC‐2 D179 variants employ substrate‐assisted catalysis for ceftazidime hydrolysis, involving the ring amine of the aminothiazole group to promote deacylation and catalytic turnover. Moreover, the shift in the WT conformation of N170 contributes to reduced deacylation and an altered spectrum of enzymatic activity. [ABSTRACT FROM AUTHOR]

Ampicillin (AMP) and cefazolin (CZO) are commonly used β-lactam antibiotics which are extensively globally produced. Additionally, AMP and CZO are known to have relatively high ecotoxicity. Notably, the mix of AMP and CZO creates a synergistic effect that is more harmful to the environment, and how exposure to AMP-CZO can induce synergism in algae remains virtually unknown. To yield comprehensive mechanistic insights into chemical toxicity, including dose–response relationships and variations in species sensitivity, the integration of multiple endpoints with de novo transcriptomics analyses were used in this study. We employed Selenastrum capricornutum to investigate its toxicological responses to AMP and CZO at various biological levels, with the aim of elucidating the underlying mechanisms. Our assessment of multiple endpoints revealed a significant growth inhibition in response to AMP at the relevant concentrations. This inhibition was associated with increased levels of reactive oxygen species (ROS) and perturbations in nitrogen metabolism, carbohydrate metabolism, and energy metabolism. Growth inhibition in the presence of CZO and the AMP-CZO combination was linked to reduced viability levels, elevated ROS production, decreased total soluble protein content, inhibited photosynthesis, and disruptions in the key signaling pathways related to starch and sucrose metabolism, ribosome function, amino acid biosynthesis, and the production of secondary metabolites. It was concluded from the physiological level that the synergistic effect of Chlorophyll a (Chla) and Superoxide dismutase (SOD) activity strengthened the growth inhibition of S. capricornutum in the AMP-CZO synergistic group. According to the results of transcriptomic analysis, the simultaneous down-regulation of LHCA4, LHCA1, LHCA5, and sodA destroyed the functions of the photosynthetic system and the antioxidant system, respectively. Such information is invaluable for environmental risk assessments. The results provided critical knowledge for a better understanding of the potential ecological impacts of these antibiotics on non-target organisms. [ABSTRACT FROM AUTHOR]

ABSTRACT Non-heritable, phenotypic drug resistance toward antibiotics challenges antibiotic therapies. Characteristics of such phenotypic resistance have implications for the evolution of heritable resistance. Diverse forms of phenotypic resistance have been described, but phenotypic resistance characteristics remain less explored than genetic resistance. Here, we add novel combinations of single-cell characteristics of phenotypic resistant E. coli cells and compare those to characteristics of susceptible cells of the parental population by exposure to different levels of recurrent ampicillin antibiotic. Contrasting expectations, we did not find commonly described characteristics of phenotypic resistant cells that arrest growth or near growth. We find that under ampicillin exposure, phenotypic resistant cells reduced their growth rate by about 50% compared to growth rates prior to antibiotic exposure. The growth reduction is a delayed alteration to antibiotic exposure, suggesting an induced response and not a stochastic switch or caused by a predetermined state as frequently described. Phenotypic resistant cells exhibiting constant slowed growth survived best under ampicillin exposure and, contrary to expectations, not only fast-growing cells suffered high mortality triggered by ampicillin but also growth-arrested cells. Our findings support diverse modes of phenotypic resistance, and we revealed resistant cell characteristics that have been associated with enhanced genetically fixed resistance evolution, which supports claims of an underappreciated role of phenotypic resistant cells toward genetic resistance evolution. A better understanding of phenotypic resistance will benefit combatting genetic resistance by developing and engulfing effective anti-phenotypic resistance strategies.IMPORTANCEAntibiotic resistance is a major challenge for modern medicine. Aside from genetic resistance to antibiotics, phenotypic resistance that is not heritable might play a crucial role for the evolution of antibiotic resistance. Using a highly controlled microfluidic system, we characterize single cells under recurrent exposure to antibiotics. Fluctuating antibiotic exposure is likely experienced under common antibiotic therapies. These phenotypic resistant cell characteristics differ from previously described phenotypic resistance, highlighting the diversity of modes of resistance. The phenotypic characteristics of resistant cells we identify also imply that such cells might provide a stepping stone toward genetic resistance, thereby causing treatment failure.

Summary: Background: Accurate prediction of the optimal dose for β-lactam antibiotics in neonatal sepsis is challenging. We aimed to evaluate whether a reliable clinical decision support system (CDSS) based on machine learning (ML) can assist clinicians in making optimal dose selections. Methods: Five β-lactam antibiotics (amoxicillin, ceftazidime, cefotaxime, meropenem and latamoxef), commonly used to treat neonatal sepsis, were selected. The CDSS was constructed by incorporating the drug, patient, dosage, pharmacodynamic, and microbiological factors. The CatBoost ML algorithm was used to build the CDSS. Real-world studies were used to evaluate the CDSS performance. Virtual trials were used to compare the CDSS-optimized doses with guideline-recommended doses. Findings: For a specific drug, by entering the patient characteristics and pharmacodynamic (PD) target (50%/70%/100% fraction of time that the free drug concentration is above the minimal inhibitory concentration [fT > MIC]), the CDSS can determine whether the planned dosing regimen will achieve the PD target and suggest an optimal dose. The prediction accuracy of all five drugs was >80.0% in the real-world validation. Compared with the PopPK model, the overall accuracy, precision, recall, and F1-Score improved by 10.7%, 22.1%, 64.2%, and 43.1%, respectively. Using the CDSS-optimized doses, the average probability of target concentration attainment increased by 58.2% compared to the guideline-recommended doses. Interpretation: An ML-based CDSS was successfully constructed to assist clinicians in selecting optimal β-lactam antibiotic doses. Funding: This work was supported by the National Natural Science Foundation of China; Distinguished Young and Middle-aged Scholar of Shandong University; National Key Research and Development Program of China.

Abstract The sequence of a carboxy-terminal of the β-lactam sensor-transducer protein (BlaR-CTD) from Bacillus licheniformis ATCC14580 was extracted from US7745193B2 patent and expressed in E. coli using pColdI vector as a soluble His-tag recombinant protein. In this study, several excipients were used to improve the stability of recombinant BlaR-CTD and obtain the optimal formulation for this protein using response surface methodology (RSM)/ Central Composite Design (CCD). Total protein concentration was measured by UV spectroscopy and the Bradford test. A total of 7 various factors were designed using four different excipients including Glycerol, Sucrose, Triton x-100, and Tween-20, and three different buffers like Tris, Borate, and PBS. By obtaining suitable excipients and buffer i.e. glycerol and sucrose, pH ranging from 7 to 9 were evaluated. The pH 7.62, glycerol 15.35%, and sucrose 152.52 mM were determined as the most suitable for improving the thermal stability of recombinant BlaR-CTD.

The sequence of a carboxy-terminal of the β-lactam sensor-transducer protein (BlaR-CTD) from Bacillus licheniformis ATCC14580 was extracted from US7745193B2 patent and expressed in E. coli using pColdI vector as a soluble His-tag recombinant protein. In this study, several excipients were used to improve the stability of recombinant BlaR-CTD and obtain the optimal formulation for this protein using response surface methodology (RSM)/ Central Composite Design (CCD). Total protein concentration was measured by UV spectroscopy and the Bradford test. A total of 7 various factors were designed using four different excipients including Glycerol, Sucrose, Triton x-100, and Tween-20, and three different buffers like Tris, Borate, and PBS. By obtaining suitable excipients and buffer i.e. glycerol and sucrose, pH ranging from 7 to 9 were evaluated. The pH 7.62, glycerol 15.35%, and sucrose 152.52 mM were determined as the most suitable for improving the thermal stability of recombinant BlaR-CTD. [ABSTRACT FROM AUTHOR]

Bacillus cereus sensu stricto is a foodborne pathogen that causes food poisoning. Their spore and biofilm-forming abilities persist in various environments and foods. This study investigated the prevalence, virulence, antibiotic resistance, and genetic diversity of B. cereus s. s. strains isolated from various food samples. Of 179 samples, 22.34% were positive for B. cereus s. s., with significantly high detection rates in milk products and raw chicken meat. Forty strains were isolated from positive samples. Matrix-assisted laser desorption ionization/time of flight mass spectrometry analysis revealed nine distinct clusters and multi-locus sequence typing revealed 34 sequence types including 23 novel sequences, demonstrating high genetic diversity among the isolates. PCR analysis revealed that all the strains contained at least one toxin gene, but none contained the cytK gene. Antibiotic resistance tests revealed that all isolates were classified as multidrug-resistant, with high resistance levels, particularly to β-lactam antibiotics and vancomycin, but were susceptible to gentamicin. All isolates showed variations in biofilm formation. This study highlights the significant public health risk due to B. cereus s. s. and underscores the need for stringent monitoring and control measures in food production to manage antimicrobial resistance and ensure food safety.

Due to widespread overuse, pharmaceutical compounds, such as antibiotics, are becoming increasingly prevalent in greater concentrations in aquatic ecosystems. In this study, we investigated the capacity of the white-rot fungus, Coriolopsis gallica (a high-laccase-producing fungus), to biodegrade ampicillin under different cultivation conditions. The biodegradation of the antibiotic was confirmed using high-performance liquid chromatography, and its antibacterial activity was evaluated using the bacterial growth inhibition agar well diffusion method, with Escherichia coli as an ampicillin-sensitive test strain. C. gallica successfully eliminated ampicillin (50 mg L−1) after 6 days of incubation in a liquid medium. The best results were achieved with a 9-day-old fungal culture, which treated a high concentration (500 mg L−1) of ampicillin within 3 days. This higher antibiotic removal rate was concomitant with the maximum laccase production in the culture supernatant. Meanwhile, four consecutive doses of 500 mg L−1 of ampicillin were removed by the same fungal culture within 24 days. After that, the fungus failed to remove the antibiotic. The measurement of the ligninolytic enzyme activity showed that C. gallica laccase might participate in the bioremediation of ampicillin.

Monitoring plasma concentrations of β-lactam antibiotics is crucial, particularly in critically ill patients, where variations in concentrations can lead to treatment failure or adverse events. Standardized antimicrobial regimens may not be effective for all patients, especially in special groups with altered physiological parameters. Pharmacokinetic/pharmacodynamic (PK/PD) studies highlight the time-dependent antibacterial activity of these antibiotics, emphasizing the need for personalized dosing. Therapeutic drug monitoring (TDM) is essential, requiring rapid and accurate analytical methods for precise determination of drugs in biological material (typically plasma or serum). This study presents a novel capillary zone electrophoresis–tandem mass spectrometry (CZE-MS/MS) method designed for the simultaneous quantification of five penicillin antibiotics, two cephalosporins, one carbapenem, and two β-lactamase inhibitors in a single run. The method involves a simple sample pretreatment—precipitation with organic solvent—and has a run time of 20 min. Optimization of CZE separation conditions revealed that 20 mM ammonium hydrogen carbonate (NH4HCO3) serves as the optimal background electrolyte (BGE). Positive electrospray ionization (ESI) mode, with isopropyl alcohol (IP)/10 mM ammonium formate water solution (50/50, v/v) as the sheath liquid, was identified as the optimal condition for MS detection. Method validation according to the Food and Drug Administration (FDA) guideline for development of bioanalytical methods demonstrated satisfactory selectivity, linearity, recovery, robustness, and stability. The method’s practicality was evaluated using the Blue Applicability Grade Index (BAGI), yielding a score of 77.5. Moreover, the greenness of the proposed method was evaluated by two commonly used metric tools—Analytical GREEnness (AGREE) and Green Analytical Procedure Index (GAPI). The developed CZE-MS/MS method offers a practical and reliable approach for quantifying a broad spectrum of β-lactam antibiotics in plasma. Its ability to simultaneously quantify multiple analytes in a single run, coupled with a straightforward sample pretreatment, positions it as a valuable and prospective tool for TDM in critically ill patients.

Invasive infections caused by Streptococcus pyogfenes (iGAS), commonly known as Group A Streptococcus, represent a significant public health concern due to their potential for rapid progression and life-threatening complications. Epidemiologically, invasive GAS infections exhibit a diverse global distribution, affecting individuals of all ages with varying predisposing factors. The pathogenesis of invasive GAS involves an array of virulence factors that contribute to tissue invasion, immune evasion, and systemic dissemination. In pediatrics, in the last few years, an increase in iGAS infections has been reported worldwide becoming a challenging disease to diagnose and treat promptly. This review highlights the current knowledge on pathogenesis, clinical presentations, and therapeutic approaches for iGAS in children.

Ampicillin (AMP) and cefazolin (CZO) are commonly used β-lactam antibiotics which are extensively globally produced. Additionally, AMP and CZO are known to have relatively high ecotoxicity. Notably, the mix of AMP and CZO creates a synergistic effect that is more harmful to the environment, and how exposure to AMP-CZO can induce synergism in algae remains virtually unknown. To yield comprehensive mechanistic insights into chemical toxicity, including dose–response relationships and variations in species sensitivity, the integration of multiple endpoints with de novo transcriptomics analyses were used in this study. We employed Selenastrum capricornutum to investigate its toxicological responses to AMP and CZO at various biological levels, with the aim of elucidating the underlying mechanisms. Our assessment of multiple endpoints revealed a significant growth inhibition in response to AMP at the relevant concentrations. This inhibition was associated with increased levels of reactive oxygen species (ROS) and perturbations in nitrogen metabolism, carbohydrate metabolism, and energy metabolism. Growth inhibition in the presence of CZO and the AMP-CZO combination was linked to reduced viability levels, elevated ROS production, decreased total soluble protein content, inhibited photosynthesis, and disruptions in the key signaling pathways related to starch and sucrose metabolism, ribosome function, amino acid biosynthesis, and the production of secondary metabolites. It was concluded from the physiological level that the synergistic effect of Chlorophyll a (Chla) and Superoxide dismutase (SOD) activity strengthened the growth inhibition of S. capricornutum in the AMP-CZO synergistic group. According to the results of transcriptomic analysis, the simultaneous down-regulation of LHCA4, LHCA1, LHCA5, and sodA destroyed the functions of the photosynthetic system and the antioxidant system, respectively. Such information is invaluable for environmental risk assessments. The results provided critical knowledge for a better understanding of the potential ecological impacts of these antibiotics on non-target organisms.

Type I Alexander disease (AxD) presents with paroxysmal neurodegeneration, refractory epilepsy, and encephalopathy in the first years of life and is associated with a poor prognosis. Although there is no treatment, mild symptomatic improvement has been reported in one case of adult Alexander treated with ceftriaxone, given its interaction with the mutant glial fibrillary acid protein (GFAP) responsible for the disease's pathogenesis. We describe a patient presenting with irritability starting at 2 months of age, initially attributed to gastroesophageal reflux. A ventriculoperitoneal shunt was placed at 3 months of age due to hydrocephalus secondary to aqueduct stenosis detected through an MRI scan, but the irritability persisted. At 5 months, a new brain MRI was performed due to irritability worsening, onset of abnormal ocular movements and seizures. In addition genetic testing was performed. AxD was diagnosed due to the mutation c.716G>A (p.Arg239His) in GFAP. Since irritability had worsened and had not responded to levomepromazine, treatment with amoxicillin (80 mg/kg/day) was attempted to modulate glutamate levels. The patient showed a striking improvement of irritability in 48 h that persisted over the next months. The patient had frequent daily seizures which did not respond to valproate, clonazepam, or phenobarbital. Perampanel, a postsynaptic AMPA receptor antagonist, was added to phenobarbital and he was seizure free for more than 3 months. Drugs modulating glutamate levels in the central nervous system, including β-lactam antibiotics and perampanel, may have an important role in the symptomatic treatment of AxD and other neurodegenerative diseases where glutamatergic excitotoxicity is a pathogenic determinant. PLAIN LANGUAGE SUMMARY: Alexander disease is a rare and serious condition that affects the brain, often leading to neurodegeneration (brain damage), seizures, and other problems in early childhood. The disease is caused by a mutation in a gene called GFAP. There is no cure, and current treatments mainly focus on relieving symptoms. This article discusses the case of a baby who showed signs of irritability and seizures from a young age. The baby was diagnosed with Alexander disease after brain scans and genetic testing. Despite treatment with various drugs, the baby continued to experience seizures and irritability. The doctors decided to try amoxicillin, a common antibiotic, because of its potential to help control the disease by affecting a brain chemical called glutamate. Surprisingly, the baby's irritability improved within 2 days of starting amoxicillin, and the improvement lasted for several months. However, the seizures persisted until another medication, perampanel, was added. This combination controlled the baby's seizures for over 3 months. Unfortunately, the baby passed away at 13 months due to complications from the disease. However, doctors believe that drugs like amoxicillin and perampanel could be promising treatments for managing symptoms of Alexander disease and other similar brain conditions in the future, especially where excess glutamate plays a role in the damage. This case suggests that these treatments may help control irritability and seizures, offering hope for better management of this challenging disease., (© 2024 The Author(s). Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Antibiotic-resistant enterococci represent a significant global health challenge. Unfortunately, most β-lactam antibiotics are not applicable for enterococcal infections due to intrinsic resistance. To extend their antimicrobial spectrum, polycationic peptides are conjugated to examples from each of the four classes of β-lactam antibiotics. Remarkably, the β-lactam-peptide conjugates gained an up to 1000-fold increase in antimicrobial activity against vancomycin-susceptible and vancomycin-resistant enterococci. Even against β-lactam-resistant Gram-negative strains, the conjugates are found to be effective despite their size exceeding the exclusion volume of porins. The extraordinary gain of activity can be explained by an altered mode of killing. Of note, the conjugates showed a concentration-dependent activity in contrast to the parent β-lactam antibiotics that exhibited a time-dependent mode of action. In comparison to the parent β-lactams, the conjugates showed altered affinities to the penicillin-binding proteins. Furthermore, it is found that peptide conjugation also resulted in a different elimination route of the compounds when administered to rodents. In mice systemically infected with vancomycin-resistant enterococci, treatment with a β-lactam-peptide conjugate reduced bacterial burden in the liver compared to its originator. Therefore, peptide modification of β-lactam antibiotics represents a promising platform strategy to broaden their efficacy spectrum, particularly against enterococci., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Objectives: To investigate the incidence and influencing factors of allergic reactions to cephalosporins., Methods: A cross-sectional study of 29 medical institutions in Zhejiang Province was conducted from April 2021 to June 2021. The incidence of allergic reactions to cephalosporins was investigated, and the influencing factors of cephalosporin-induced allergic reactions were analyzed by Poisson regression., Results: A total of 56 155 patients were included in this study. The total incidence of allergic reactions to cephalosporin was 1.67‰, the highest incidence of anaphylaxis occurred for ceftizoxime (4.27‰), followed by ceftriaxone (3.49‰) and cefotaxime (2.40‰). There was no significant difference in the incidence of allergic reactions between patients with negative skin tests and those without skin tests (1.75‰ vs . 1.63‰, RR =1.07, 95% CI : 0.70-1.63, P >0.05). Poisson regression showed that body mass index (BMI) <18.5 kg/m 2 ( RR =2.43, 95% CI : 1.23-4.82, P <0.05) and history of β-lactam antibiotics allergy ( RR =33.88, 95% CI : 1.47-781.12, P <0.05) increased cephalosporin-induced anaphylaxis. Compared with cefuroxime, the risk of allergic reactions was increased for ceftriaxone ( RR =3.08, 95% CI : 1.70-5.59, P <0.01), ceftazidime ( RR =1.89, 95% CI : 1.03-3.47, P <0.05), and ceftizoxime ( RR =3.74, 95% CI : 1.64-8.50, P <0.01)., Conclusions: Lower BMI and history of β-lactam antibiotics allergy increase the risk of cephalosporin allergic reactions. The routine skin test may not reduce the occurrence of allergic reactions to cephalosporins.

The presence of antibiotic residues in the aquatic environments poses great potential risks to the aquatic organisms, and even human health. Elucidating the interaction mechanisms between antibiotics and biomacromolecules is crucial for accurately assessing and preventing their potential risks. Therefore, the toxicity of three beta-lactam antibiotics on Escherichia coli (E. coli) was investigated by using the time-dependent toxicity microplate analysis method in this study. Then, molecular docking and molecular dynamics simulation technologies were used to elucidate the potential molecular interactions between β-lactam antibiotics and penicillin-binding proteins of E. coli, and their correlation with the physical and chemical behaviors observed in the physiological and biochemical experiments. The results show that three antibiotics exert inhibitory effects on E. coli cells by modifying their membrane permeability, and even more severe cell damage including rupture, wrinkling, adhesion, indentation, elongation and size alterations. But, toxic effect of the three antibiotics on E. coli varies, and toxicity order is followed by meropenem > cefoperazone > amoxicillin. Van der Waals forces play a vital role in the molecular interactions between the three antibiotics penicillin binding protein of E. coli and the sequence of binding free energy is consistent with the observed toxicity order. Shape compensation is the principal determinant for the binding of antibiotics to penicillin binding proteins, which pertains to the drug-induced alteration in the three-dimensional conformation of penicillin binding proteins., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: The efficacy of extended infusions (EI) of β-lactam antibiotics for optimising outcomes in febrile neutropenia is unclear. We assessed whether the administration of β-lactams was more effective in EI than in intermittent infusion (II) for the treatment of febrile neutropenia., Methods: We performed a randomized, open-label, superiority clinical trial of patients with febrile neutropenia at four Spanish university hospitals. Patients undergoing haematopoietic stem cell transplantation or with acute leukaemia receiving chemotherapy who required empirical antibiotic treatment for febrile neutropenia were randomly assigned (1:1) to receive EI of β-lactam or II after a first dose in bolus. The choice of antipseudomonal β-lactam was left to the discretion of the attending physician. The primary endpoint was treatment success at day 5, defined as defervescence without modifying the antibiotic treatment. Secondary endpoints included adverse events, attainment of the pharmacokinetic/pharmacodynamic target of 50%, 75%, and 100%ƒ u T  > MIC , and 30-day mortality., Results: From November 19, 2019 to June 22, 2022, 295 patients were screened for eligibility, of whom 150 were randomly assigned to receive EI (n = 77) or II (n = 73) of the antipseudomonal β-lactam of choice. In the intention-to-treat analysis, treatment success at day 5 was achieved in 39/77 patients (50.6%) receiving EI versus 46/73 patients (63.0%) receiving II (risk difference, -12.4%; 95% CI, -29.4 to 4.7; p 0.17). The pharmacokinetic/pharmacodynamic targets of 75% and 100% ƒ u T  > MIC for empirical treatment were achieved more frequently in the EI group. No statistically significant differences were found between groups in terms of adverse events or 30-day mortality., Discussion: Our findings do not support the routine use of empirical EI of β-lactams in febrile neutropenia. Further studies should consider the clinical heterogeneity of febrile neutropenia and focus on patients with sepsis or septic shock and microbiologically documented infections, particularly those with infections caused by microorganisms less susceptible to β-lactams., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Novel β-lactam antibiotics as well as other kinds of antibiotics have been used to treat complicated urinary tract infections (cUTIs); however, their efficacy and safety remain controversial., Objective: We conducted a systematic review with meta-analysis to explore the efficacy and safety of novel β-lactam antibiotics versus other antibiotics against cUTIs., Methods: PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched systematically from inception through 15 March 2024 for clinical trials comparing novel β-lactam antibiotics with other antibiotics for treatment of cUTIs. Random-effects models were used to evaluate the impact of treatment on the risk ratio (RR) of clinical response, microbiologic response, adverse effects (AEs), serious adverse effects (SAEs). The quality of evidence was evaluated with the Cochrane Risk of Bias assessment tool. The review was registered in INPLASY (INPLASY202440054)., Results: Ten randomized controlled trials involving 5, 925 patients met our inclusion criteria. Our meta-analysis revealed that there was no significant difference in overall clinical response (RR = 1.02), AEs (RR = 1.07), SAEs (RR = 1.20) between novel β-lactam antibiotics groups and other antibiotics groups. However, a significant difference was found in a subgroup of clinical cure rates at the end of treatment between novel β-lactam antibiotics groups and carbapenems groups, with low heterogeneity (RR = 1.02). A significant difference was observed in microbiologic response (RR = 1.11). Subgroup analysis revealed a significant difference in microbiologic response between novel BBL/BLS groups and carbapenems groups (RR = 1.13, I 2 = 21%, P = 0.005). Differences was observed between novel BBL/BLS groups and piperacillin/tazobactam sodium groups (RR = 1.21, I 2 = 70%, P = 0.02). Similar results were obtained from subgroup analysis of the difference in microbiologic response between novel β-lactam antibiotics groups and ertapenem groups (RR = 0.92, I 2 = 0, P = 0.01)., Conclusion: Novel β-lactam antibiotics had similar overall clinical cure, AEs, SAE, to other antibiotics in the treatment of cUTIs. However, novel β-lactam antibiotics demonstrated superior clinical cure rates compared to carbapenems in a subgroup analysis, and exhibited better microbiologic response than other antibiotics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Quan, Wang, Han, Xing, Zhang and Cang.)

β-lactam antibiotics are the most successful and commonly used antibacterial agents, but the emergence of resistance to these drugs has become a global health threat. The expression of β-lactamase enzymes produced by pathogens, which hydrolyze the amide bond of the β-lactam ring, is the major mechanism for bacterial resistance to β-lactams. In particular, among class A, B, C and D β-lactamases, metallo-β-lactamases (MBLs, class B β-lactamases) are considered crucial contributors to resistance in gram-negative bacteria. To combat β-lactamase-mediated resistance, great efforts have been made to develop β-lactamase inhibitors that restore the activity of β-lactams. Some β-lactamase inhibitors, such as diazabicyclooctanes (DBOs) and boronic acid derivatives, have also been approved by the FDA. Inhibitors used in the clinic can inactivate mostly serine-β-lactamases (SBLs, class A, C, and D β-lactamases) but have not been effective against MBLs until now. In order to develop new inhibitors particularly for MBLs, various attempts have been suggested. Based on structural and mechanical studies of MBL enzymes, several MBL inhibitor candidates, including taniborbactam in phase 3 and xeruborbactam in phase 1, have been introduced in recent years. However, designing potent inhibitors that are effective against all subclasses of MBLs is still extremely challenging. This review summarizes not only the types of β-lactamase and mechanisms by which β-lactam antibiotics are inactivated, but also the research finding on β-lactamase inhibitors targeting these enzymes. These detailed information on β-lactamases and their inhibitors could give valuable information for novel β-lactamase inhibitors design. [Display omitted] • The characteristics of β-lactam antibiotics and their action mechanisms. • The classification of β-lactamases and their mechanism of β-lactam hydrolysis. • The classification of metallo-β-lactamases by structure and mechanism. • β-lactamase inhibitors approved by FDA. • Promising metallo-β-lactamase inhibitors in the clinic. [ABSTRACT FROM AUTHOR]

Non-heritable, phenotypic drug resistance toward antibiotics challenges antibiotic therapies. Characteristics of such phenotypic resistance have implications for the evolution of heritable resistance. Diverse forms of phenotypic resistance have been described, but phenotypic resistance characteristics remain less explored than genetic resistance. Here, we add novel combinations of single-cell characteristics of phenotypic resistant E. coli cells and compare those to characteristics of susceptible cells of the parental population by exposure to different levels of recurrent ampicillin antibiotic. Contrasting expectations, we did not find commonly described characteristics of phenotypic resistant cells that arrest growth or near growth. We find that under ampicillin exposure, phenotypic resistant cells reduced their growth rate by about 50% compared to growth rates prior to antibiotic exposure. The growth reduction is a delayed alteration to antibiotic exposure, suggesting an induced response and not a stochastic switch or caused by a predetermined state as frequently described. Phenotypic resistant cells exhibiting constant slowed growth survived best under ampicillin exposure and, contrary to expectations, not only fast-growing cells suffered high mortality triggered by ampicillin but also growth-arrested cells. Our findings support diverse modes of phenotypic resistance, and we revealed resistant cell characteristics that have been associated with enhanced genetically fixed resistance evolution, which supports claims of an underappreciated role of phenotypic resistant cells toward genetic resistance evolution. A better understanding of phenotypic resistance will benefit combatting genetic resistance by developing and engulfing effective anti-phenotypic resistance strategies., Importance: Antibiotic resistance is a major challenge for modern medicine. Aside from genetic resistance to antibiotics, phenotypic resistance that is not heritable might play a crucial role for the evolution of antibiotic resistance. Using a highly controlled microfluidic system, we characterize single cells under recurrent exposure to antibiotics. Fluctuating antibiotic exposure is likely experienced under common antibiotic therapies. These phenotypic resistant cell characteristics differ from previously described phenotypic resistance, highlighting the diversity of modes of resistance. The phenotypic characteristics of resistant cells we identify also imply that such cells might provide a stepping stone toward genetic resistance, thereby causing treatment failure., Competing Interests: The authors declare no conflict of interest.

The synergetic strategy has created tremendous advantages in drug-resistance bacterial infection treatment, whereas challenges related to novel compound discovery and identifying drug-binding targets still remain. The mechanisms of antimicrobial resistance involving β -lactamase catalysis and the degradation of β -lactam antibiotics are being revealed, with relevant therapies promising to improve the efficacy of existing major classes of antibiotics in the foreseeable future. In this study, it is demonstrated that nordalbergin, a coumarin isolated from the wood bark of Dalbergia sissoo , efficiently potentiated the activities of β -lactam antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) by suppressing β -lactamase performance and improving the bacterial biofilm susceptibility to antibiotics. Nordalbergin was found to destabilize the cell membrane and promote its permeabilization. Moreover, nordalbergin efficiently improved the therapeutic efficacy of amoxicillin against MRSA pneumonia in mice, as supported by the lower bacterial load, attenuated pathological damage, and decreased inflammation level. These results demonstrate that nordalbergin might be a promising synergist of amoxicillin against MRSA infections. This study provided a new approach for developing potentiators for β -lactam antibiotics against MRSA infections.

Background: Accurate prediction of the optimal dose for β-lactam antibiotics in neonatal sepsis is challenging. We aimed to evaluate whether a reliable clinical decision support system (CDSS) based on machine learning (ML) can assist clinicians in making optimal dose selections., Methods: Five β-lactam antibiotics (amoxicillin, ceftazidime, cefotaxime, meropenem and latamoxef), commonly used to treat neonatal sepsis, were selected. The CDSS was constructed by incorporating the drug, patient, dosage, pharmacodynamic, and microbiological factors. The CatBoost ML algorithm was used to build the CDSS. Real-world studies were used to evaluate the CDSS performance. Virtual trials were used to compare the CDSS-optimized doses with guideline-recommended doses., Findings: For a specific drug, by entering the patient characteristics and pharmacodynamic (PD) target (50%/70%/100% fraction of time that the free drug concentration is above the minimal inhibitory concentration [fT > MIC]), the CDSS can determine whether the planned dosing regimen will achieve the PD target and suggest an optimal dose. The prediction accuracy of all five drugs was >80.0% in the real-world validation. Compared with the PopPK model, the overall accuracy, precision, recall, and F1-Score improved by 10.7%, 22.1%, 64.2%, and 43.1%, respectively. Using the CDSS-optimized doses, the average probability of target concentration attainment increased by 58.2% compared to the guideline-recommended doses., Interpretation: An ML-based CDSS was successfully constructed to assist clinicians in selecting optimal β-lactam antibiotic doses., Funding: This work was supported by the National Natural Science Foundation of China; Distinguished Young and Middle-aged Scholar of Shandong University; National Key Research and Development Program of China., Competing Interests: Declaration of interests All authors declare that they have no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

[Display omitted] • First evidence of β-lactamase activity found in UVI31+, a BolA homologue from Chlamydomonas reinhardtii. • Sulbactam, a β-lactam analogue shows low-μM affinity to UVI31+, indicating potential functional relevance. • Mutation studies pinpoint the active site, serine-55 as responsible for β-lactamase activity. • The study provides valuable insights into potential drug targets and therapeutic strategies against antibiotic resistance. β-Lactamases (EC 3.5.2.6) confer resistance against β-lactam group-containing antibiotics in bacteria and higher eukaryotes, including humans. Pathogenic bacterial resistance against β-lactam antibiotics is a primary concern for potential therapeutic developments and drug targets. Here, we report putative β-lactamase activity, sulbactam binding (a β-lactam analogue) in the low μM affinity range, and site-specific interaction studies of a 14 kDa UV- and dark-inducible protein (abbreviated as UVI31+, a BolA homologue) from Chlamydomonas reinhartii. Intriguingly, the solution NMR structure of UVI31 + bears no resemblance to other known β-lactamases; however, the sulbactam binding is found at two sites rich in positively charged residues, mainly at the L2 loop regions and the N-terminus. Using NMR spectroscopy, ITC and MD simulations, we map the ligand binding sites in UVI31 + providing atomic-level insights into its β-lactamase activity. Current study is the first report on β-lactamase activity of UVI31+, a BolA analogue, from C. reinhartii. Furthermore, our mutation studies reveal that the active site serine-55 is crucial for β-lactamase activity. [ABSTRACT FROM AUTHOR]

Polymerized impurities in β -lactam antibiotics can induce allergic reactions, which seriously threaten the health of patients. In order to study the polymerized impurities in cefoxitin sodium for injection, a novel approach based on the use of two-dimensional liquid chromatography coupled with time-of-flight mass spectrometry (2D-LC-TOF MS) was applied. In the 1st dimension, high performance size exclusion chromatography (HPSEC) with a TSK-G2000SWxl column was employed. Column switching was applied for the desalination of the mobile phase used to separate polymerized impurities in the 1st dimension before they were transferred to the 2nd dimension which utilized reversed phase liquid chromatography (RP-LC) and TOF MS for further structural characterization. The structures of four polymerized impurities (which were all previously unknown) in cefoxitin sodium for injection were deduced based on the MS2 data. One novel polymerized impurity (PI–I), with 2H less than the molecular weight of two molecules of cefoxitin (M r. 852.09), was found to be the most abundant (>50 %) in almost all the samples examined and could be regarded as the marker polymer of cefoxitin sodium for injection. This work also showed the great potential of the 2D-LC-TOF MS approach in structural characterization of unknown impurities separated with a mobile phase containing non-volatile phosphate in the 1st dimension. [Display omitted] • Novel approach to characterize unstable impurities separated by a non-volatile mobile phase. • Four novel PIs found in cefoxitin based on MSn data. [ABSTRACT FROM AUTHOR]

The increasing severity of problems posed by drug-resistant pathogens has compelled researchers to explore innovative approaches for infection prevention. Among these strategies, conjugation methods stand out for their convenience and high efficacy. In this study, multiple covalent conjugates were synthesized, incorporating the natural antimicrobial peptide epsilon-poly-l-lysine (EPL) and two commonly used β-lactam antibiotics: penicillin G or ampicillin. Enhanced antimicrobial efficacy against typical Gram-negative pathogens, along with faster kill kinetics compared to combination approaches, was demonstrated by the EPL-Ampicillin covalent conjugates. Their antimicrobial mechanism was also substantiated through SEM and fluorescence tests in this work, confirming the inheritance of membrane-disrupting properties from EPL. Furthermore, the excellent biocompatibility of the raw materials was reserved in the covalent conjugates. This simplified conjugation method holds promise for the development of infection therapeutic drugs and potentially restores the sensitivity of conventional antibiotics to drug-resistant pathogens by introducing membrane-disrupting mechanisms.

Antibacterial resistance to β-lactams in microorganisms has been attributed majorly to alterations in penicillin-binding proteins (PBPs) coupled with β-lactams' inactivation by β-lactamase. Consequently, the identification of a novel class of therapeutics with improved modulatory action on the PBPs is imperative and plant secondary metabolites, including phenolics, have found relevance in this regard. For the first time in this study, the over 10,000 phenolics currently known were computationally evaluated against PBP3 of Pseudomonas aeruginosa , a superbug implicated in several nosocomial infections. In doing this, a library of phenolics with an affinity for PBP3 of P. aeruginosa was screened using structure-activity relationship-based pharmacophore and molecular docking approaches. Subsequent thermodynamic screening of the top five phenolics with higher docking scores, more drug-likeness attributes, and feasible synthetic accessibility was achieved through a 120 ns molecular dynamic (MD) simulation. Four of the top five hits had higher binding free energy than cefotaxime (-18.72 kcal/mol), with catechin-3-rhamside having the highest affinity (-28.99 kcal/mol). All the hits were stable at the active site of the PBP3, with catechin-3-rhamside being the most stable (2.14 Å), and established important interactions with Ser294, implicated in the catalytic activity of PBP3. Also, PBP3 became more compact with less fluctuation of the active site amino acid residues following the binding of the hits. These observations are indicative of the potential of the test compounds as PBP3 inhibitors, with catechin-3-rhamside being the most prominent of the compounds that could be further improved for enhanced druggability against PBP3 in vitro and in vivo. Communicated by Ramaswamy H. Sarma.