Antimicrobial resistance: a global multifaceted phenomenon

Targeting biofilm formation in Candida albicans with halogenated pyrrolopyrimidine derivatives

Growing concern over environmental contaminants, including pharmaceuticals and antifungal agents, highlights their role in promoting resistance and biofilm formation by microorganisms. Antifungal resistance, especially in drug-resistant Candida spp., poses a global threat, worsened by the widespread use of antifungal agents in both clinical applications and environmental contamination. This study investigates the antibiofilm properties of various halogenated pyrrolo pyrimidine derivatives, specifically 4-chloro-5-iodo-7H-pyrrolo[2,3-d]pyrimidine (10) and 2,4-dichloro-5-iodo-7H-pyrrolo[2,3-d]pyrimidine (16), against fluconazole-resistant C. albicans. Both compounds demonstrated strong biofilm inhibition, with 16 showing greater efficacy even at lower concentrations. qRT-PCR analysis revealed downregulation of key biofilm- and hyphae/germ tube-relating genes, including ALS3, HWP1, and ECE1, alongside upregulation of stress response and biofilm regulator genes such as CDR11, GST3, IFD6, UCF1, YWP1, and ZAP1, indicating complex regulatory responses to the treatments. Molecular docking analysis revealed that these compounds bind effectively to the binding cavity of the ALS3 protein, with halogen atoms playing a key role in stabilizing interaction. Compound 16 exhibited minimal cytotoxicity in Brassica rapa and Caenorhabditis elegans models, suggesting a favorable ADMET safety profile. Confocal microscopy analysis confirmed the compounds effectiveness in preventing biofilm formation when applied as biodegradable PLGA coatings on biomaterial surfaces. These findings suggest that 16 holds promise as a potent antifungal agent with reduced environmental impact, offering both efficacy and sustainability.

Electrochemical β-lactamase immunostrip sensor with 3D hydrogel-paper scaffold for rapid detection & post-antibiotic therapy monitoring in drug-resistant bloodstream infections

BACKGROUND

The increasing prevalence of drug-resistant bacterial bloodstream infections, particularly those caused by Methicillin-resistant Staphylococcus aureus (MRSA), presents a critical global healthcare challenge. Current diagnostic methods often lack the speed and sensitivity necessary for timely antibiotic interventions, leading to poor patient outcomes and increased resistance due to misuse of broad-spectrum antibiotics. Existing platforms rarely combine rapid detection, low detection limits, and real-time therapy monitoring, leaving a crucial gap in effective infection management.

RESULTS

This study introduces an electrochemical immunostrip sensor for the rapid detection of β-lactamase (BL), an enzyme associated with drug resistance. Using a novel 3D hydrogel-paper scaffold, the sensor achieves a detection limit of 0.146 mU/ml and accurately detects BL-producing pathogens, including MRSA, from clinical samples with bacterial loads as low as 102 CFU/ml. The platform provides post culture detection results within 1 h, post antibiotic therapy monitoring within 4 h and demonstrates high specificity (∼100 %) by differentiating BL-producing strains from non-producing isolates.

SIGNIFICANCE AND NOVELTY

This study introduces a new electrochemical smart immunostrip sensor integrated with a 3D hydrogel-paper scaffold for β-lactamase detection, which offers high sensitivity and specificity. Unlike conventional diagnostics, it enables user-friendly, rapid, cost-effective detection within 1 h post-blood culture and real-time antibiotic therapy monitoring in just 4 h, transforming clinically actionable point-of-care (POC) management of drug-resistant bloodstream infections.

Challenges and opportunities for AMR research in the ASEAN following the One Health approach

Background

Antimicrobial resistance (AMR) has emerged as a significant global challenge and Southeast Asia with rapid economic and population growth faces substantial challenge in dealing with emerging infectious diseases and antimicrobial resistance. Here we present the recommendations of a workshop that explored the challenges and opportunities for One Health approach towards AMR research in three countries of AEAN, namely, Cambodia, Laos, and Vietnam.

Methods

A workshop was organised in Hanoi, Vietnam in August 2023, involving participants involved in AMR research across varied sectors from three participating countries to prioritise the strategies that can be implemented in the region to fructify the One Health approach to tackle AMR. A modified Delphi approach was used to prioritise the top 10 Global Priority Research Questions for the region as developed by the Quadripartite (FAO, WHO, WOAH and UNEP). An iterative process was adopted to map priorities according to their impact and feasibility of application.

Results

Collaborative initiatives, such as a common platform for listing the research goals, a web-based surveillance mechanism, and an enhanced AMR awareness curricula were identified as the steps forward. A consensus statement highlighting the critical needs for improved technical and infrastructure capacity, collaboration between sectors, increased funding, and systematic data analysis was drafted.

Discussion

The participating countries have National Action Plans guided by the World Health Organization's Global Action Plan on AMR, but limited collaboration between human health and other sectors has impeded the benefits that One Health approach may achieve in the region. The recommendations include the need for improved technical and infrastructure capacity, and data collection across One Health sectors, besides increasing awareness at multiple levels.

Conclusion

A collaborative and coordinated effort to apply One Health initiatives for tackling AMR in the ASEAN region is imperative. The workshop formulated a roadmap for future direction by identifying priorities aimed at enhancing collaboration, addressing infrastructure gaps, and contributing to an effective intervention in the fight against AMR in the region.

MSC-derived extracellular vesicles: Precision miRNA delivery for overcoming cancer therapy resistance

Cancer remains a prominent worldwide health concern, presenting existing therapies with frequent difficulties, including major toxicity, limited effectiveness, and treatment resistance emergence. These issues highlight the necessity for novel and enhanced remedies. Exosomes, tiny extracellular vesicles that facilitate intercellular communication, have attracted interest for their potential medicinal applications. Carrying a variety of molecules, including microRNAs, small interfering RNAs, long non-coding RNAs, proteins, lipids, and DNA, these vesicles are positioned as promising cancer treatment options. Current studies have increasingly investigated the capacity of microRNAs as a strategic approach for combating malignancy. Mesenchymal stem cells (MSC) are recognized for their aptitude to augment blood vessel formation, safeguard against cellular death, and modulate immune responses. Consequently, researchers examine exosomes derived from MSCs as a safer, non-cellular choice over therapies employing MSCs, which risk undesirable differentiation. The focus is shifting towards employing miRNA-encapsulated exosomes sourced from MSCs to target and heal cancerous cells selectively. However, the exact functions of miRNAs within MSC-derived exosomes in the context of cancer are still not fully understood. Additional exploration is necessary to clarify the role of these miRNAs in malignancy progression and to pinpoint viable therapeutic targets. This review offers a comprehensive examination of exosomes derived from mesenchymal stem cells, focusing on the encapsulation of miRNAs, methods for enhancing cellular uptake and stability, and their potential applications in cancer treatment. It also addresses the difficulties linked to this methodology and considers future avenues, including insights from current clinical oncology research.

Nanomaterial-based drug delivery systems in overcoming bacterial resistance: Current review

Antimicrobial resistance is one of the most serious contemporary global health concerns, threatening the effectiveness of existing antibiotics and resulting in morbidity, mortality, and economic burdens. This review examines the contribution of nanomaterial-based drug delivery systems to solving the problems associated with bacterial resistance and provides a thorough overview of their mechanisms of action, efficiency, and perspectives for the future. Owing to their unique physicochemical properties, nanomaterials reveal new ways of passing through the traditional mechanisms of bacterial defence connected to the permeability barrier of membranes, efflux pumps, and biofilm formation. This review addresses the different types of nanomaterials, including metallic nanoparticles, liposomes, and polymeric nanoparticles, in terms of their antimicrobial properties and modes of action. More emphasis has been placed on the critical discussion of recent studies on such active systems. Both in vitro and in vivo models are discussed, with particular attention paid to multidrug-resistant bacteria. This review begins by reviewing the urgency for antimicrobial resistance (AMR) by citing recent statistics, which indicate that the number of deaths and reasons for financial losses continue to increase. A background is then provided on the limitations of existing antibiotic therapies and the pressing need to develop innovative approaches. Nanomaterial-based drug delivery systems have been proposed as promising solutions because of their potential to improve drug solubility, stability, and targeted delivery, although side effects can also be mitigated. In addition to established knowledge, this review also covers ongoing debates on the continuous risks associated with the use of nanomaterials, such as toxicity and environmental impact. This discussion emphasizes the optimization of nanomaterial design to target specific bacteria, and rigorous clinical trials to establish safety and efficacy in humans. It concludes with reflections on the future directions of nanomaterial-based drug delivery systems in fighting AMR, underlining the need for an interdisciplinary approach, along with continuous research efforts to translate these promising technologies into clinical practice. As the fight against bacterial resistance reaches its peak, nanomaterials may be the key to developing next-generation antimicrobial therapies.

Recent Advances in Immunotherapeutic and Vaccine-Based Approaches for the Treatment of Drug-Resistant Bacterial Infections

Antimicrobial resistance poses a grave threat to global public health. Although new antibiotics are urgently needed, most share resistance mechanisms with existing drugs, thereby necessitating the development of alternative antibacterial therapeutics. Various immunotherapeutic agents, including monoclonal antibodies, therapeutic vaccines, cellular therapies, and immunomodulators, have been developed and explored to treat drug-resistant bacterial infections. This review comprehensively summarizes recent advancements in immunotherapies and vaccine-based approaches as alternative strategies to combat drug-resistant bacterial infections. Our findings indicate that immunotherapy offers several advantages over traditional antibiotics, such as enhanced specificity, long-term effects, overcoming resistance mechanisms, broad applicability, potential for combination therapies, personalized medicine, and reduced toxicity. Also, formulation and delivery strategies, including nanoparticles, liposomes, cellular vehicles, and diverse administration routes, have been employed to improve the efficacy and targeting of these immunotherapeutic agents. In-depth evaluations of promising preclinical and clinical studies demonstrate their potential effectiveness against pathogens such as Pseudomonas aeruginosa, Escherichia coli, Mycobacterium tuberculosis, Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Helicobacter pylori. These suggest that immunotherapy is a promising alternative to address the growing challenge of drug-resistant bacterial infections, potentially revolutionizing infection management strategies.

Selective pressures for public antibiotic resistance

The rapid increase of antibiotic-resistant pathogens is severely limiting our current treatment possibilities. An important subset of the resistance mechanisms conferring antibiotic resistance have public effects, allowing otherwise susceptible bacteria to also survive antibiotic treatment. As susceptible bacteria can survive treatment without bearing the metabolic cost of producing the resistance mechanism, there is potential to increase their relative frequency in the population and, as such, select against resistant bacteria. Multiple studies showed that this altered selection for resistance is dependent on various environmental and treatment parameters. In this review, we provide a comprehensive overview of their most important findings and describe the main factors impacting the selection for resistance. In-depth understanding of the driving forces behind selection can aid in the design and implementation of alternative treatments which limit the risk of resistance development.

Artificial intelligence in drug resistance management

This review highlights the application of artificial intelligence (AI), particularly deep learning and machine learning (ML), in managing antimicrobial resistance (AMR). Key findings demonstrate that AI models, such as Naïve Bayes, Decision Trees (DT), Random Forest (RF), Support Vector Machines (SVM), and Artificial Neural Networks (ANN), have significantly advanced the prediction of drug resistance patterns and the identification of novel antibiotics. These algorithms have effectively optimized antibiotic use, predicted resistance phenotypes, and identified new drug candidates. AI has also facilitated the detection of AMR-associated mutations, offering new insights into the spread of resistance and potential interventions. Despite data privacy and algorithm transparency challenges, AI presents a promising tool in combating AMR, with implications for improving patient outcomes, enhancing disease management, and addressing global public health concerns. However, realizing its full potential requires overcoming issues related to data scarcity, ethical considerations, and fostering interdisciplinary collaboration.

The Study of Escherichia coli as Antimicrobial-Resistant Sentinel Microorganism Isolated in the Farms of Three Districts of Ankara by MALDI-TOF MS and Genomic Analysis

One Health is a unified approach that aims to sustain and maintain the health of humans, animals and the ecosystem. The environment plays an important role in the spread of resistance genes, as it is an unlimited source of antimicrobial resistance genes. Escherichia coli can acquire and spread resistance genes from its environment. Extended-spectrum beta-lactamase (ESBL)-producing E. coli is a global concern because it can hydrolyse many beta-lactam antibiotics. In this study, the aim was to isolate E. coli from faeces and soil samples collected from cattle, sheep and poultry in three districts (Golbası, Haymana and Cubuk) where livestock (cattle, sheep and poultry) farming activities are intensively carried out. In addition, the antibiotic susceptibility of the isolated E. coli was to be determined using phenotypic and genotypic methods and the presence of ESBLs was to be determined using a double-disc synergy test. All 120 E. coli isolates were confirmed by the MALDI-TOF MS method. The resistance rates of all isolates were as follows: ampicillin, 12.5%; trimethoprim/sulfamethoxazole, 6.6%; cefazolin, 0.83%; ciprofloxacin, 2.5%; ceftazidime, 0.83%; cefotaxime, 1.6% and ceftriaxone, 1.6%. Cefazolin (99.1%) and trimethoprim/sulfamethoxazole (0.83%) were determined to have intermediate susceptibility. Only one E. coli strain was found to be ESBL positive via phenotypic methods, and whole-genome analysis was performed on this strain. As a result of whole-genome analysis, ESBL-related CTX-M-14 and TEM-1 genes were found in the plasmids. This is the first study on the determination of antibiotic susceptibility and the presence of ESBL in E. coli isolated from the soil and faeces samples of farms in these regions. More studies are needed to determine and understand antibiotic resistance and ESBL positivity in environmental samples. Therefore, the One Health approach should be emphasised.

Factors influencing physicians' antimicrobial prescribing decisions: A systematic review of qualitative studies

Inappropriate and overuse of antimicrobials is increasing antimicrobial resistance. Understanding physicians' antimicrobial decision-making is essential for developing interventions to optimize prescribing. The aim of this review was to identify the factors that influence physicians' antimicrobial prescribing decisions. A systematic literature search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Embase, Medline and Scopus were searched from 2014 onwards using three key concepts: antimicrobial, prescribing and attitude. The search identified 11 038 articles for review. Studies were included if they used qualitative methods and obtained data directly from physicians. Factors influencing antimicrobial prescribing were extracted and categorized into physician-related, patient-related, medication- and condition-related, and external factors. A model of the antimicrobial prescribing process was created to illustrate how these factors influence decision-making. Fifty-three articles from 23 countries met the inclusion criteria. Forty factors influencing antimicrobial prescribing were identified, with the most common being time pressures, patient/carer demand for antimicrobials, diagnostic uncertainty, clinical experience, and the use of evidence-based guidelines and diagnostic tests. The harm to the patient and the physician of underprescribing were considered to outweigh the potential population harm of antimicrobial resistance due to overprescribing. Antimicrobial decision making is a complex process influenced by many different types of factors at each point in the prescribing journey. Awareness of these factors is vital for the success of interventions aiming to optimize antimicrobial prescribing. Future interventions should investigate how to balance individual and population harm whilst considering the individual factors that influence prescribing decisions.

Deciphering the Mechanism of Action of a Short, Synthetic Designer AMP Against Gram-Negative Bacteria

Antimicrobial peptides (AMPs), produced in various organisms, including plants, as a first line of defense, are potent, functionally versatile, fast-acting small peptides with a net charge and diverse structures. Most AMPs demonstrate potent antibacterial activity, and AMPs with multimodal actions can potentially delay the development of antimicrobial resistance (AMR), one of the top 10 global public health challenges categorized by the WHO. Notably, the FDA has already approved several AMPs (Mol. Wt. ≤ 2 kDa) as antibiotics; however, there are not enough new-age antibiotics in the current pipeline to combat the looming problem of AMR in the clinic. Nevertheless, despite their potential, natural AMPs have their fair share of shortcomings for straightforward therapeutic applications. Therefore, extensive research on developing designer synthetic AMPs with broad-spectrum antimicrobial activity is currently being undertaken to mitigate the AMR challenge. In this context, we recently demonstrated a short synthetic designer AMP (SR17: ≤ 16 aa, mol. Wt. ≤ 2 kDa) that exhibits broad-spectrum bacteriostatic and bactericidal action against both gram-negative (Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii) and gram-positive (Staphylococcus aureus) bacteria. Interestingly, in gram-negative bacteria, the outer membrane proteins (OMPs) play a key role in transporting nutrients like iron from their surroundings through siderophores, which play a crucial role in various biochemical processes essential for their survival and growth. In the current study, the ability of SR17 to target the iron-transporting OMPs acting as the siderophore uptake system is investigated through computational techniques. A series of docking and molecular dynamics (MD) simulation studies involving iron transporters of various gram-negative bacteria indicate that SR17 can occupy the binding pocket in the OMPs necessary for binding of the iron-chelated siderophores, which is likely to prevent the further uptake of siderophores, affecting the growth and survival of the bacteria. Additionally, SR17 may potentially reach the bacterial cytoplasm by utilizing the siderophore uptake system and disrupt essential cytoplasmic processes, leading to the death of the bacteria, as observed in experimental studies.

Serum-Stable, Cationic, α-Helical AMPs to Combat Infections of ESKAPE Pathogens and C. albicans

Expedition in the rate of development of antimicrobial resistance accompanied by the slowdown in the development of new antimicrobials has led to a dire necessity to develop an alternate class of antimicrobial agents. Antimicrobial peptides (AMPs), available in nature, are effective molecules that can combat microbial infections. However, due to several inherent shortcomings such as salt sensitivity of their potency, short systemic half-lives owing to protease and serum degradation, and cytotoxicity, their commercial success is limited. Inspired by α helical AMPs present in nature, here in this work, we have developed two short, cationic, helical AMPs RR-12 and FL-13. Both peptides exhibited high broad-spectrum antimicrobial activity, salt tolerance, prompt bactericidal activity, considerable serum stability, remaining non-cytotoxic and non-hemolytic at relevant microbicidal concentrations. The designed AMPs were membranolytic toward the microbial strains, though there were subtle differences in the mechanism owing to the variation in the composition of the cell membranes in different microbes. Rigorous experimental techniques and molecular dynamics (MD) simulations were performed to understand the structure, activity, and their mechanisms in detail. Positive charge, balanced hydrophobicity-hydrophilicity, and helical conformation were the different attributes that led to the development of the superior performance of the AMPs, making them valuable additions to the repertoire of therapeutically promising antimicrobials.

Characteristics and Antibacterial Activity of Staphylococcus aureus Phage-Derived Endolysin LysP4

The rise in multidrug resistance and strong biofilm-forming ability of Staphylococcus aureus has led to significant public health concerns. Phage or phage-derived components, such as depolymerase or endolysin, have been considered as potential alternatives to antibiotics for combating antibiotic-resistant bacterial infections. In this study, we cloned and expressed a Staphylococcus aureus phage endolysin, LysP4, and identified its lytic activity. The bactericidal effect of LysP4 was more pronounced against planktonic cells in the logarithmic phase compared to those in the stationary phase. LysP4 reduces bacterial counts by 3 log CFU/mL in 60 min and about 2 log CFU/mL during the stationary phase. LysP4 exhibited optimal lytic activity at pH 5.0-7.0 and remained stable across a temperature range of 16 to 40 °C, with maximal activity observed at 37 °C. LysP4 effectively targets 31 of 38 Staphylococcus strains and successfully eliminates biofilms, reducing bacterial counts by 4 log CFU/mL when combined with vancomycin. Notably, LysP4 demonstrated no hemolytic effects on human red blood cells and no toxic effects on embryonic kidney cells or lung cancer cells. Based on these findings, we believe that LysP4 holds promise as a biological control agent against Staphylococcus infections.

The burden of healthcare-associated infections in Brazil: multi-hospital point prevalence using a matched case-control study

BACKGROUND

Healthcare-associated infections (HAIs) have a significant impact on patient care worldwide and have serious implications for the Brazilian healthcare system.

OBJECTIVES

This study aimed to describe the trends in HAIs in adult intensive care units (ICUs) using data from a national point-prevalence survey.

DESIGN AND SETTING

A point-prevalence study was conducted in 2019 across adult intensive ICUs in large acute care hospitals in Brazil.

METHODS

A matched case-control study was performed to assess the risk factors associated with the development of infection.

RESULTS

A total of 386 patients from 15 hospitals were studied, of whom 102 (26.4%; 102/386) were infected, and 76.5% had at least one ICU-acquired infection. In clinical-surgical ICUs (CSU), the prevalence of infections acquired in the unit was 77.9%, whereas in Coronary ICUs (COU), it was 68.7%. There was a predominance of pneumonia (51.0%), mainly caused by Gram-negative non-fermenters, and bloodstream infections (34.4%), predominantly caused by coagulase-negative Staphylococcus (CoNS). In the risk factor analysis, cancer and general antimicrobial use were independently associated.

CONCLUSION

This study found a high burden of HAIs in adult ICUs in Brazil, mainly associated with the high use of antibiotics for infections and a worse prognosis.

Emergence of plasmid-mediated fosfomycin resistance among Escherichia coli harboring fosA4, tet(X4), and mcr-1 genes in wild birds

Fosfomycin represents a last-line reserve antibiotic for the treatment of infections caused by multidrug-resistant (MDR) bacteria. Nevertheless, the advent of plasmid-mediated fosfomycin resistance among bacteria from humans and food animals incurs great concern. This study reports the detection and genomic portrait of the plasmid-mediated fosfomycin resistance gene, fosA4, amid Escherichia coli from wild birds co-harboring plasmid-mediated tigecycline resistance gene, tet(X4), and colistin resistance gene, mcr-1. A total of 100 samples from fecal droppings of wild birds in the urban parks in Faisalabad, Pakistan were subjected for the isolation and characterization of fosfomycin-resistant E. coli. The fosA4 gene was identified in 11 (11%) of the E. coli isolates, and all exhibited an MDR phenotype. Genome sequencing confirmed that all the fosA4-positive isolates also co-harbored the mobile tigecycline resistance tet(X4) gene on a large MDR IncFII plasmid. One isolate PKF8 belonging to ST48 also co-carried the colistin resistance gene mcr-1 on the IncHI2 plasmid. To the extent of our knowledge, this is the first discovery of E. coli isolates in wild birds co-harboring the mcr-1, fosA4, and tet(X4) genes. The emergence of these pivotal antimicrobial resistance genes in wild birds native to South Asia with their close association to humans and animals is alarming. Our findings highlight the urgent need for further surveillance of bacterial resistance to last-resort antibiotics in the clinics, animal farming, and environment with the One Health approach.

IMPORTANCE

The global spread of the plasmid-mediated fosfomycin resistance gene fosA4 bearing Escherichia coli strains incurs a public health concern. However, research focusing on the pervasiveness of fosA4-positive isolates in wild birds is still rare, and to the best of our knowledge, this is the first documentation from South Asia highlighting the concurrent presence of the fosA4, mcr-1, and tet(X4) genes within E. coli isolates recovered from fecal samples of wild birds in Pakistan. This co-existence of ARGs along with phylogenetic analysis revealed that MDR plasmids carried by E. coli isolates have the ability to spread horizontally between wild birds, food animals, and humans. Co-existence of fosA4, tet(X4), and mcr-1-carrying plasmids is worrying and warrants further investigation.

Study of biological safety of camel milk after treatment with different antibiotics

The use of antibiotics in camels is generally based on the doses applied to cattle, despite the known differences in plasma pharmacokinetics between camel and cattle. The demand for camel milk increased due to the belief that traditional camel farming practices produce safe milk with health benefits. For assessing the importance of antibiotic residues in camel milk and to propose a convenient withdrawal period, a trial was conducted on 10 lactating camels (7-12 years old; 450 kg life weight (LW), 7-8 liter of milk production per day) at mid-lactation receiving an injection of 40 mL of Pen-strep® (benzylpenicillin-procaine 200,000 IU/1 ml and dihydrostreptomycin sulfate 200 mg/1 ml) and Nitox® (oxytetracycline dihydrate 200 mg/1 ml). The antibiotic residues were measured in the milk 30 min after injection then on day 1, 2, 3, 7, 9, 14, 19, 24 and 56 by using HPLC-MS/MS. Results showed that penicillin's mean residual concentration (0.3 ± 0.013 mg/kg) remained 7.5 times above the maximum residue limit (MRL) even on 56th day. In contrast, streptomycin fell below the MRL within 30 minutes and averaged 1 µg/kg by day 56. Oxytetracycline levels exceeded the MRL (0.1 mg/kg) until day 14 but dropped to a safe level of 0.018 ± 0.01 mg/kg by day 24. In conclusion, the decline in streptomycin concentration post-injection appeared rapid and efficient, the elimination of penicillin and tetracycline was slow. These preliminary results lead to considering the necessity to adapt the waiting time to the dairy camel.

Evaluating the Effect of an Essential Oil Blend on the Growth and Fitness of Gram-Positive and Gram-Negative Bacteria

The increasing prevalence of antibiotic-resistant bacteria has necessitated the exploration of alternative antimicrobial agents, particularly natural products like essential oils. This study investigated the antibacterial potential of a unique blend of four essential oils (EOB) across a gradient of concentrations (0.1 to 50%) against Gram-positive and Gram-negative bacteria using an adapted broth microdilution method, minimum inhibitory concentrations (MICs), and 24-h growth assays. The Gram-positive bacteria were Staphylococcus epidermidis and Bacillus subtilis, while the Gram-negative bacteria were Escherichia coli and Klebsiella aerogenes. The results demonstrated that the EOB exerted a concentration-dependent inhibitory effect on bacterial growth, with MICs determined at 25% for all the species tested. Growth curve analysis revealed that lower concentrations of the EOB (0.1 to 0.78%) allowed for normal bacterial proliferation, while at intermediate concentrations (1.56 to 3.13%), inconsistent trends in growth were exhibited. At higher concentrations (25 and 50%), the EOB effectively halted bacterial growth, as indicated by flat growth curves. The increase in the lag phase and the decrease in the growth rate at a sub-MIC concentration (12.5%) suggest a significant effect on bacterial adaptation and survival. Relative fitness analyses further highlighted the inhibitory effects of higher essential oil concentrations. S. epidermidis and E. coli had a significant (p < 0.05) reduction in fitness starting from the 6.25% concentration, while the other two species experienced a significant (p < 0.001) reduction in relative fitness from a concentration of 12.5%. These findings underscore the potential of this EOB as an effective antimicrobial agent, particularly in the context of rising antibiotic resistance. Furthermore, the study suggests that the EOB used in the present study could be integrated into therapeutic strategies as a natural alternative or adjunct to traditional antibiotics, offering a promising avenue for combating resistant bacterial strains.

Antimicrobial Susceptibility and Toxin Gene Profiles of Commensal Clostridium perfringens Isolates from Turkeys in Hungarian Poultry Farms (2022-2023)

Background: The global spread of antimicrobial resistance (AMR) remains one of the greatest challenges of our time, necessitating collaboration among professionals in both the animal and public health sectors. One bacterial species that is developing AMR is Clostridium perfringens. It causes serious bacterial infections and continues to cause significant economic losses in the poultry industry. Methods: This study aimed to evaluate the antimicrobial susceptibility profiles of commensal C. perfringens strains isolated from large-scale turkey flocks in Hungary using minimum inhibitory concentration (MIC) determination. We complemented our research with polymerase chain reaction (PCR) analysis to detect the major and minor toxin genes that are characteristic of the species and to explore the potential associations between gene presence and antimicrobial resistance profiles. Results: A total of 146 commensal isolates were examined. Sensitivity to penicillin was reduced, with only 44.5% of isolates remaining susceptible, whereas 87.7% of isolates were sensitive to amoxicillin. The PCR results revealed that all isolates carried the alpha major toxin gene, 23.9% harbored the beta major toxin gene, 15.8% the beta2 minor toxin gene, 3.4% the NetB minor toxin gene, and 2.7% the epsilon major toxin gene. No statistically significant associations were observed between the presence of toxin genes and the antimicrobial susceptibility profiles of the isolates; the MIC values showed no correlation with the presence of toxin-producing genes. Conclusions:Clostridium perfringens isolates retained susceptibility to beta-lactam antibiotics, which remain the primary choice for treatment. Regular monitoring can aid in establishing temporal trends. Future studies should include larger sample sizes and employ next-generation sequencing to further investigate multidrug-resistant strains.

Quorum sensing inhibitors (QSIs): a patent review (2019-2023)

INTRODUCTION

The collective behavior of bacteria is regulated by Quorum Sensing (QS), in which bacteria release chemical signals and express virulence genes in a cell density-dependent manner. Quorum Sensing inhibitors (QSIs) are a large class of natural and synthetic compounds that have the potential to competitively inhibit the Quorum Sensing (QS) systems of several pathogens blocking their virulence mechanisms. They are considered promising compounds to deal with antimicrobial resistance, providing an opportunity to develop new drugs against these targets.

AREAS COVERED

The present review represents a comprehensive analysis of patents and patent applications available on Espacenet and Google Patent, from 2019 to 2023 referring to the therapeutic use of Quorum Sensing inhibitors.

EXPERT OPINION

Unlike classical antibiotics, which target the basic cellular metabolic processes, QSIs provide a promising alternative to attenuating virulence and pathogenicity without putting selective pressure on bacteria. The general belief is that QSIs pose no or little selective pressure on bacteria since these do not affect their growth. To date, QSIs are seen as the most promising alternative to traditional antibiotics. The next big step in this area of research is its succession to the clinical stage.

Novel strategies for vancomycin-resistant Enterococcus faecalis biofilm control: bacteriophage (vB_EfaS_ZC1), propolis, and their combined effects in an ex vivo endodontic model

BACKGROUND

Endodontic treatment failures are predominantly attributed to Enterococcus faecalis (E. faecalis) infection, a Gram-positive coccus. E. faecalis forms biofilms, resist multiple antibiotics, and can withstand endodontic disinfection protocols. Vancomycin-resistant strains, in particular, are challenging to treat and are associated with serious medical complications.

METHODS

A novel phage, vB_EfaS_ZC1, was isolated and characterized. Its lytic activity against E. faecalis was assessed in vitro through time-killing and biofilm assays. The phage's stability under various conditions was determined. Genomic analysis was conducted to characterize the phage and its virulence. The phage, propolis, and their combination were evaluated as an intracanal irrigation solution against a 4-week E. faecalis mature biofilm, using an ex vivo infected human dentin model. The antibiofilm activity was analyzed using a colony-forming unit assay, field emission scanning electron microscopy, and confocal laser scanning microscopy.

RESULTS

The isolated phage, vB_EfaS_ZC1, a siphovirus with prolate capsid, exhibited strong lytic activity against Vancomycin-resistant strains. In vitro assays indicated its effectiveness in inhibiting planktonic growth and disrupting mature biofilms. The phage remained stable under wide range of temperatures (- 80 to 60 °C), tolerated pH levels from 4 to 11; however the phage viability significantly reduced after UV exposure. Genomic analysis strongly suggests the phage's virulence and suitability for therapeutic applications; neither lysogeny markers nor antibiotic resistance markers were identified. Phylogenetic analysis clustered vB_EfaS_ZC1 within the genus Saphexavirus. The phage, both alone and in combination with propolis, demonstrated potent antibiofilm effects compared to conventional root canal irrigation.

CONCLUSION

Phage vB_EfaS_ZC1 demonstrates a promising therapy, either individually or in combination with propolis, for addressing challenging endodontic infections caused by E. faecalis.

Antimicrobial resistance pattern of Acinetobacter baumannii clinical isolate in Ethiopia. A systematic review and meta-analysis

BACKGROUND

Antimicrobial resistance (AMR) is a growing global health threat. Acinetobacter baumannii (A. baumannii) emerged as one of the most concerning critical priority pathogens due to its ability to develop resistance to multiple antimicrobial agents. In Ethiopia, the public health impact of AMR is increasingly significant, with A. baumannii responsible for a variety of infections. Although A. baumannii causes a range of infections in Ethiopian patients, the drug resistance status of the clinical isolates has not been thoroughly assessed. Therefore, this systematic review and meta-analysis aimed to determine the country-wide AMR of A. baumannii.

METHODS

This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a search of articles on PubMed, Web of Science, Science Direct, Scopes electronic databases, Google Scholar search engine, and institutional repositories/libraries for studies published between 2015 and 2024. Eligible studies on A. baumannii-related infections and AMR in Ethiopia were assessed for quality using the Joanna Briggs Institute (JBI) criteria. Data on study characteristics were extracted, and statistical analyses, including heterogeneity (Invers of variance), publication bias (Eggers test), and subgroup analyses, were performed using STATA 17.0. A random effect model was used to compute the pooled prevalence of AMR.

RESULTS

This systematic review and meta-analysis of 26 Ethiopian studies (26,539 participants) found an A. baumannii prevalence of 3.99% (95% CI: 3.01-4.98%) and 9.13% of all bacterial infections (95% CI: 6.73-11.54%). The most common infections were surgical site infections, urinary tract infections, pneumonia, and sepsis. Pooled resistance to antibiotics varied, with amikacin showing the lowest resistance (20.27%) (95% CI: 11.51-29.03) and cefotaxime the highest (83.18) (95% CI: 71.87-94.48). A pooled multi-drug resistant (MDR) A. baumannii was found in 88.22% (95% CI: 82.28-94.15) of isolates, with regional and infection-type variations, particularly in higher prevalence in Oromia and Amhara regions and sepsis cases.

CONCLUSION

This systematic review underscores the alarming rise of antimicrobial resistance in A. baumannii, particularly against carbapenems. The findings highlight a high prevalence of MDR A. baumannii and widespread extended-spectrum beta-lactamase production, with notable regional variations in resistance patterns. These high resistance rates reinforce A. baumannii as a critical global health threat, necessitating urgent interventions such as enhanced antimicrobial stewardship programs, improved infection control measures, and the development of alternative treatment strategies. Healthcare professionals, policymakers, and researchers must collaborate to mitigate the clinical and public health impact of this pathogen.

PROTOCOL REGISTRATION

This systematic review and meta-analysis was registered on PROSPERO (Registration ID: CRD42024623927).

Identification of potential therapeutics by targeting AcrB protein from AcrAB-TolC multidrug efflux pump of Escherichia coli: an in-silico exploration

Antibiotic resistance, a critical global health concern, arises as bacteria and other microbes evolve to resist drugs. The AcrB protein, a key component of the AcrAB-TolC multidrug efflux pump in Escherichia coli, plays a significant role in antibiotic resistance and presents an opportunity for new drug development. Inhibiting this pump has the potential to reverse antibiotic resistance and restore drug efficacy. This study explores potential molecules that target the AcrB protein as a novel therapeutic strategy against multidrug-resistant (MDR) Gram-negative bacteria, utilizing in-silico techniques. The initial step in the selection of ligands involved gathering compounds from the PubChem database that are structurally similar to erythromycin A, with a cutoff score of 80 or higher in the similarity search. Stringent drug-likeness criteria were applied, yielding 111 compounds that share structural similarities with erythromycin A. Virtual screening against the target protein identified 72 compounds with promising docking scores between -6.13 and -3.06 kcal/mol using the MtiOpenScreen web server. Subsequently, four compounds (CID:102055530, CID:101369593, CID:139312504, and CID:143044924), along with the control compound (erythromycin A), were selected for further analysis. These analyses included re-docking, molecular dynamics simulations, free binding energy calculations, and PCA-based free energy landscape investigation. The findings suggest that the identified compounds could serve as foundations for developing new inhibitors targeting the AcrB protein, offering a promising strategy to counteract bacterial resistance. This research supports the need for further experimental validation to confirm these in-silico predictions and to potentially advance these compounds through the drug development process.

Metagenomic analysis of human, animal, and environmental samples identifies potential emerging pathogens, profiles antibiotic resistance genes, and reveals horizontal gene transfer dynamics

Antimicrobial resistance (AMR) poses a significant threat to global health. The indiscriminate use of antibiotics has accelerated the emergence and spread of drug-resistant bacteria, compromising our ability to treat infectious diseases. A One Health approach is essential to address this urgent issue, recognizing the interconnectedness of human, animal, and environmental health. This study investigated the prevalence and transmission of AMR in a temporary settlement in Kathmandu, Nepal. By employing shotgun metagenomics, we analyzed a diverse range of samples, including human fecal samples, avian fecal samples, and environmental samples. Our analysis revealed a complex interplay of pathogenic bacteria, virulence factors (VF), and antimicrobial resistance genes (ARGs) across these different domains. We identified a diverse range of bacterial species, including potential pathogens, in both human and animal samples. Notably, Prevotella spp. was the dominant gut bacterium in human samples. Additionally, we detected a wide range of phages and viruses, including Stx-2 converting phages, which can contribute to the virulence of Shiga toxin-producing E. coli (STEC) strains. Our analysis revealed the presence of 72 virulence factor genes and 53 ARG subtypes across the studied samples. Poultry samples exhibited the highest number of ARG subtypes, suggesting that the intensive use of antibiotics in poultry production may contribute to the dissemination of AMR. Furthermore, we observed frequent horizontal gene transfer (HGT) events, with gut microbiomes serving as key reservoirs for ARGs. This study underscores the critical role of a One Health approach in addressing AMR. By integrating human, animal, and environmental health perspectives, we can better understand the complex dynamics of AMR and develop effective strategies for prevention and control. Our findings highlight the urgent need for robust surveillance systems, judicious antibiotic use, and improved hygiene practices to mitigate the impact of AMR on public health.

Listeria monocytogenes and Listeriosis: The Global Enigma

Listeria monocytogenes is an intracellular, Gram-positive, non-spore-forming, non-encapsulated, facultative anaerobic, rod-shaped, and psychrotrophic food-borne pathogen that causes the infection, listeriosis, thus it attracts great attention following listeriosis outbreaks, which are often associated with high mortality rates. The prevalence of listeriosis is quite low globally; however, the most recent and deadliest outbreak occurred in South Africa, during which 216 persons lost their lives. L. monocytogenes is endowed with the potential to multiply through a wide range of harsh environmental conditions, forming biofilms on varying surfaces in the food industry, as well as having persistent and antibiotic-resistant cells, which pose a major threat and burden to the ready-to-eat food industry. A more frustrating characteristic of this bacterium is its strain divergence, alongside an increased level of antibiotic resistance registered among the strains of L. monocytogenes recovered from food, humans, and environmental sources, especially to those antibiotics involved in the treatment of human listeriosis. Antibiotic resistance exerted by and among pathogenic food-borne microbes is an ongoing public health menace that continues to be an issue. Against this background, a thorough search into different databases using various search engines was performed, which led to the gathering of salient information that was organised, chronologically, based on Listeria monocytogenes and listeriosis. Altogether, the findings elaborated in this study present up-to date knowledge on different aspects of this pathogen which will improve our understanding of the mystery associated with it and the ways to prevent and control its dissemination through ready-to-eat foods. In addition, constant monitoring of the antibiotic resistance profiles of strains of L. monocytogenes from varying sources detected changes, giving an update on the trend in antibiotic resistance. Overall, monitoring of bacterial contamination serves as the key aspect in the control of the food safety output in the food industry.

Isolation and characterization of antimicrobial peptides from Lactobacillus: Exploring mechanisms of action

The rise of antibiotic-resistant bacteria necessitates the development of novel antimicrobial agents. In this study, antimicrobial peptides (AMPs) were isolated from Lactobacillus sp., yielding Bioactive Peptide I (BAP I) and Bioactive Peptide III (BAP III). Purified via gel filtration chromatography (GFC), these peptides were characterized by MALDI-TOF MS and SDS-PAGE, which confirmed their molecular masses as 4168.14 Da and 8076.45 Da, respectively, and verified their high purity. Both peptides demonstrated potent antibacterial activity against Pseudomonas aeruginosa, Streptococcus sanguinis, Bacillus cereus, and Staphylococcus aureus, with BAP I exhibiting superior efficacy. This enhanced activity is likely due to its amphipathic structure and hydrophobic C-terminal region, which promote effective bacterial membrane disruption as evidenced by FE-SEM imaging. In addition to compromising membrane integrity, both BAP I and BAP III inhibited bacterial DNA polymerase activity, as shown by reduced PCR product formation. Complementary Circular Dichroism (CD) spectroscopy analysis indicated that peptide binding induced conformational changes in Taq polymerase, reducing its α-helical and β-sheet content while increasing the proportion of random coil structures-thus enhancing the enzyme's flexibility. Molecular docking and dynamics studies further revealed stable interactions between the peptides and the enzyme, suggesting a dual mechanism of action that targets both the bacterial membrane and DNA replication processes. Collectively, these findings highlight the significant potential of BAP I and BAP III as novel antimicrobial agents against multidrug-resistant infections. Future research should focus on evaluating their safety and clinical efficacy, as well as exploring their synergistic potential with existing antibiotics to advance these peptides as therapeutic alternatives.

Catalyst-Free Synthesis of a Mechanically Tailorable, Nitric-Oxide-Releasing Organohydrogel and Its Derived Underwater Superoleophobic Coatings

Organohydrogels are an emerging class of soft materials that mimick the mechanical durability and organic solvent affinity of organogels and the biocompatibility and water swelling ability characteristics of hydrogels for prospective biomedical applications. This work introduces a facile, catalyst-free one-step chemical approach to develop an organohydrogel with impeccable antibiofouling properties following the epoxy-amine ring-opening reaction under ambient conditions. The mechanical properties of the as-fabricated organohydrogel can be tailored depending on the concentration of the epoxy-based cross-linker, from 0.10 to 1.12 MPa (compressive modulus). The affinity of the as-developed organohydrogel to both organic solvents and water was exploited to incorporate the antimicrobial nitric oxide donor (NO) molecule, S-nitroso-N-acetylpenicillamine (SNAP) from ethanol, and subsequently, the water-sensitive NO-releasing behavior of the organohydrogels was analyzed. The SNAP-incorporated organohydrogels release physiologically active levels of NO with 3.13 ± 0.27 × 10-10 and 0.36 ± 0.14 × 10-10 mol cm-2 min-1 flux of NO release observed at 0 and 24 h, respectively. The as-reported organohydrogel demonstrated excellent antibacterial activity against Escherichia coli and Staphylococcus aureus with >99% and >87% reduction, respectively, without eliciting any cytotoxicity concerns. Moreover, the organohydrogel with remarkable water uptake capacity was extended as a coating on different medically relevant polymers to demonstrate transparent underwater superoleophobicity. Thus, the facile synthesis of the reported organohydrogel and its derived underwater antifouling coating can open avenues for utility in biomedical, energy, and environmental applications.

Dominance of antimicrobial resistance bacteria and risk factors of bacteriuria infection among pregnant women in East Africa: implications for public health

BACKGROUND

Bacterial infections in pregnancy pose significant health risks in East Africa. This study estimates pooled prevalence and identifies key risk factors, addressing limited data to improve maternal health outcomes in the region.

METHODS

This study employed a systematic review and meta-analysis, analyzing data from eight East African studies (2016-2021). Searches spanned PubMed, Embase, Scopus, and more, with manual reference checks. Data quality was assessed via the Newcastle-Ottawa Scale. RevMan software with a random-effects model estimated pooled prevalence and hazard ratios for risk factors.

RESULTS

A pooled analysis of antimicrobial resistance (AMR) bacterial isolates from pregnant women in East Africa highlights concerning prevalence rates of various pathogens. Escherichia coli emerged as the most common pathogen, present in 43% (95% CI: 37-48%) of cases, followed by Staphylococcus aureus at 20% (95% CI: 0.12, 0.29) and Corynebacterium, Enterococcus, and Nocardia species (CONs) in 16% (95% CI: 10-23%) and 16% (95% CI: 12-21%) (Prevalence of K. pneumoniae). A very small proportion 6% (95% CI: 2 - 11%) was found to be infected with Pseudomonas aeruginosa. The forest plot highlights risk factors for infections in pregnant women in East Africa: antibiotic use (HR: 2.0, 95% CI: 1.5-2.6), smoking (HR: 1.3, 95% CI: 1.0-1.6), poor sanitation (HR: 1.8, 95% CI: 1.2-2.4), diabetes (HR: 2.1, 95% CI: 1.5-2.8), and age > 30 years (HR: 1.5, 95% CI: 1.1-2.0).

CONCLUSIONS

This analysis reveals a significant prevalence of bacterial infections, particularly Escherichia coli, among pregnant women in East Africa, with antimicrobial resistance (AMR) complicating treatment. The study identified several key risk factors, including antibiotic use, smoking, poor sanitation, diabetes, and age over 30, which are associated with higher rates of infection. While these findings emphasize the need for further research, the results suggest that routine bacterial screening, AMR surveillance, improved sanitation, and antibiotic stewardship are important steps in mitigating the impact of these infections. Public health strategies should prioritize high-risk groups, encourage hygiene practices, and continue to guide policy and interventions through ongoing studies.

Removal of ciprofloxacin using polymeric nanocomposites synthesized from alkylated chitosan ionic macromonomers, ionic monomers and hydrotalcite

The contamination of water systems by antibiotics such as ciprofloxacin (CIP), which is used to treat bacterial infections, poses severe risks to environmental safety and public health. To address this issue, a novel zwitterionic polymeric nanocomposite (PNs-HTC) was developed in this study. This novel material was synthesized using alkylated chitosan ionic macromonomers, ionic monomers and combined with hydrotalcite (HTC) via in situ free radical polymerization. The incorporation of quaternary ammonium and vinyl groups into the chitosan backbone, along with varying HTC contents, considerably impacted the properties of the nanocomposite. The nanocomposite was characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction, and thermogravimetric analysis. The effectiveness of PNs-HTC in removing CIP from water was evaluated under different conditions. PNs-HTC exhibited a CIP adsorption capacity of up to 84.43 mg g-1 at 318 K. Equilibrium data fitted well to the Temkin isotherm and pseudo-second-order kinetic models. The pH, ionic strength (30 % using 0.1 M NaCl), and HTC content in the nanocomposite influenced CIP adsorption, which reached a maximum of 80 % using 0.03 g of PNs-HTC. Thermodynamic studies indicated that the adsorption process was favorable, spontaneous, and endothermic and was marked by significant randomness. These findings underscore the potential of PNs-HTC as a robust material for mitigating antibiotic pollution in aquatic environments.

The tradeoffs between persistence and mutation rates at sub-inhibitory antibiotic concentrations in Staphylococcus aureus

The rational design of the antibiotic treatment of bacterial infections employs these drugs to reach concentrations that exceed the minimum needed to prevent the replication of the target bacteria. However, within a treated patient, spatial and physiological heterogeneity promotes antibiotic gradients such that the concentration of antibiotics at specific sites is below the minimum needed to inhibit bacterial growth. Here, we investigate the effects of sub-inhibitory antibiotic concentrations on three parameters central to bacterial infection and the success of antibiotic treatment, using in vitro experiments with Staphylococcus aureus and mathematical and computer-simulation models. Our results, using drugs of six different classes, demonstrate that exposure to sub-inhibitory antibiotic concentrations alters bacterial growth dynamics, increases the mutation rate to antibiotic resistance, and decreases the production of persister cells thereby reducing persistence levels. Understanding this trade-off between mutation rates and persistence levels resulting from sub-inhibitory antibiotic exposure is crucial for optimizing, and mitigating the failure of, antibiotic therapy.

IMPORTANCE

Much of the research on antibiotics and antibiotic treatment has focused on drug concentrations sufficient to prevent the growth of bacteria. These concentrations, however, are not always reached everywhere in the body. Here, we look at the effects of exposure to these low concentrations of antibiotics on the common clinically important pathogen Staphylococcus aureus. We confirm a previous finding that sub-inhibitory antibiotic exposure decreases the total growth and the growth rate of the bacteria. Moreover, we demonstrate that the level of persistence, an important mechanism for bacteria to survive antibiotics, is decreased due to sub-inhibitory exposure. However, we find that the rate of generation of resistant mutants is substantially increased. Taken together, these results reveal an important trade-off that emerges as a consequence of bacteria being exposed to sub-inhibitory concentrations of antibiotics.

Targeting Chronic Biofilm Infections With Patient-derived Phages: An In Vitro and Ex Vivo Proof-of-concept Study in Patients With Left Ventricular Assist Devices

Background

Phage therapy is being reconsidered as a valuable approach to combat antimicrobial resistance. We recently established a personalized phage therapy pipeline in healthy volunteers, where therapeutic phages were isolated from individuals' skin microbiota. In this study, we aim to validate this pipeline in end-stage heart failure patients supported by left ventricular assist devices (LVADs), focusing on phages targeting Staphylococcus epidermidis, a common pathogen responsible for LVAD infections.

Methods

Over a 2.5-year period, 45 LVAD patients were consistently sampled at their driveline exit sites and foreheads. S epidermidis strains from patients' foreheads were used to amplify patient-specific phages. Newly isolated phages were characterized and tested against S epidermidis isolates (n = 42) from the patient cohort. The virulent phage vB_SepS_BE22, isolated from a patient with a driveline infection, was further tested for its bactericidal activity against S epidermidis biofilms ex vivo with rifampicin on driveline biofilms.

Results

S epidermidis was detected in 32 patients, 3 of whom had driveline infections. Phages were isolated from 8 patients, 6 of which were unique and exhibited narrow host ranges, infecting 19%-52% of S epidermidis strains. vB_SepS_BE22, isolated from patient ID25's microbiota, was the only phage that specifically killed S epidermidis clones linked to a patient's infection. vB_SepS_BE22 also reduced bacterial loads in exponential and stationary phase cultures, as well as in biofilms on drivelines when combined with rifampicin.

Conclusions

This study validated a personalized phage therapy approach, where phages from a patient's own microbiota can be used in chronic infection settings as therapeutic agents.

Optimizing Cefiderocol Dosing Through Population Pharmacokinetic/Pharmacodynamic Simulation: An Assessment of Drug Cost Reductions

BACKGROUND

Cefiderocol is a siderophore cephalosporin antibiotic with bactericidal activity against carbapenem-resistant Enterobacterales . However, an efficient dosing strategy is yet to be developed. This study aimed to evaluate efficient lower-dose regimens and estimate potential drug cost reductions.

METHODS

This simulation study used a virtual population of 10,000 resampled individuals based on a reported population pharmacokinetic model. The target index for maximal bactericidal activity was the time for the unbound cefiderocol concentration to be above the minimum inhibitory concentration (TAM_unbound) of 100%, which was determined using a minimum inhibitory concentration distribution or specific value.

RESULTS

The probability of achieving 100% TAM_unbound with the standard, low- (reduced by 1 g or one dose), and extended low- (reduced by 2 g or 2 doses) dose regimens was nearly 100%. The lowest probability of achieving 100% TAM_unbound with the extended low-dose regimen at a creatinine clearance range of 90-120 mL/min was 86.4%. The probability of achieving TAM_unbound of 100% was more than 90% for MIC of ≤0.5 mcg/mL with the extended low-dosing regimen. Furthermore, using an efficient dosing regimen reduced the medical costs over a 10-day treatment period for 10 patients, from $122,826.50 to $62,665.69 $ and ¥12,598,187 $ to ¥5,451,173 in the United States and Japan, respectively.

CONCLUSIONSS

A lower dosing regimen for cefiderocol could result in substantial reductions in drug costs while still achieving 100% TAM_unbound.

Genomic characteristics and phylogenetic analyses of colonization and infection with carbapenem-resistant Klebsiella pneumoniae in multicenter intensive care units: a cohort study

Carbapenem-resistant Klebsiella pneumoniae (CRKp) poses a major threat to global public health. This study aimed to investigate the genomic characteristics and phylogenetic relatedness of colonization and infection with CRKp among intensive care unit (ICU) patients. A total of 61 CRKp isolates, including 29 non-ICU-acquired and 32 ICU-acquired strains, were collected by active screening and infection culture from 16 ICUs through a multicenter cohort study. Following whole-genome sequencing (WGS), seven sequence types (STs) were identified, with ST11 (60.7%) being the most dominant, followed by ST15 (27.9%). Most strains (93.4%) carried the blaKPC-2 gene, while 9.8% and 3.3% of strains carried either the blaNDM-1 gene or both genes. A high abundance of virulence genes including iutA (55.7%), rmpA (18.0%), and rmpA2 (52.5%) were identified, with iutA +rmpA2 (37.7%) being the most common combination. The IncHI1B plasmid was identified in all of the 34 strains carrying the detected virulence genes. Furthermore, results from cgMLST analysis revealed 10 clusters with highly homogeneous CRKp strains, from which the potential interregional and intrahospital spread of CRKp were hypothesized. Here, this study reveals the widespread distribution of CRKp as well as locally specific strains in different regions of Anhui Province. The observed high abundance of virulence genes requires additional attention and continued monitoring. Taken together, these findings highlight the need for coordinated efforts between healthcare facilities and networks to aid CRKp control strategies and prevent spread. Moreover, we emphasize the importance of WGS in revealing additional insights, thus improving epidemiological studies and transmission control of CRKp.

IMPORTANCE

Carbapenem-resistant K. pneumoniae (CRKp) has spread rapidly to different parts of the world and poses a serious threat to global health. High genetic diversity in CRKp can introduce complexities in disease treatment and management. Intensive care unit (ICU) patients are more susceptible to acquire CRKp infections. However, most CRKp studies have focused on strains isolated from infections, rather than cases of asymptomatic CRKp colonization. This study analyzed clinical CRKp isolates from ICU patients as well as isolate cases of active colonization screening. Findings reveal the genetic diversity of CRKp in different regions of Anhui Province, emphasizing the necessity for a more comprehensive investigation of the genomic characteristics and phylogenetic relatedness of CRKp in different regions. Data regarding antimicrobial resistance genes, virulence genes, and genetic relatedness will improve the understanding of the potential risk of CRKp to public health and aid guidance for prevention and control of CRKp.

Antibiotic Use Patterns at Jimma Medical Center in Southwest Ethiopia: A Call for Local Antibiogram-Guided Prescription

Background: The discovery of antibiotics revolutionized healthcare by significantly reducing morbidity and mortality. However, excessive and inappropriate use has led to a global surge in antimicrobial resistance, particularly in low- and middle-income countries. This study aimed to evaluate antibiotic use patterns among inpatients at Jimma Medical Center (JMC) in Southwest Ethiopia. Methods: A longitudinal observational study was conducted in February and March 2019 at JMC, focusing on patients admitted for over 24 h who received antibiotics. Data on patient demographics, clinical indications, and antibiotics prescribed were systematically collected. Antibiotic consumption rates were measured as days of therapy (DOTs) per 100 patient-days, and utilization was classified according to the World Health Organization (WHO) AWaRe (Access, Watch, and Reserve) framework. Results: A total of 384 inpatients were included, with a male predominance (53.9%) and a median age of 24 years (IQR: 5-37). In total, 634 antibiotic regimens were prescribed. According to the WHO AWaRe classification, 48.3% (306/634) were "Access" and 51.7% (328/634) were "Watch" antibiotics. Patients were treated with antibiotics for a median duration of 4 days (IQR: 2-7), leading to a total of 2880 days of antibiotic therapy. Ceftriaxone was the most commonly prescribed antibiotic, with a usage rate of 44.65 DOTs per 100 patient-days. Substantial variability was observed in empirical antibiotic regimens among treating physicians and across wards. Culture and antibiotic susceptibility testing (AST) were performed for only 4.2% of patients, and none of the treatments were modified based on susceptibility data. Conclusions: The study highlights critical issues in antibiotic prescribing at JMC, including over-reliance on "Watch" antibiotics, predominantly ceftriaxone, limited use of AST results, and deviations from standard treatment guidelines. Addressing these challenges requires implementing antimicrobial stewardship programs, developing evidence-based local treatment guidelines, and strengthening and encouraging the use of microbiology services to improve rational antibiotic use.

Cost-Effectiveness of Oral Levofloxacin Versus Amoxicillin-Clavulanate/Ciprofloxacin for Outpatient Management of Low-Risk Febrile Neutropenia in Children With Cancer in Egypt

PURPOSE

Febrile neutropenia (FN) is a common cancer complication in children. A growing body of evidence suggests that home-based care with oral antibiotics is safe and effective in carefully selected children with low-risk (LR) FN. This study aimed to assess the efficacy and safety of oral levofloxacin versus oral amoxicillin-clavulanate/ciprofloxacin in the management of LR-FN in children with cancer over a time horizon of 7 days from the National Cancer Institute (NCI) perspective.

PATIENTS AND METHODS

This is a randomized controlled study conducted at the NCI from December 2021 to September 2022, including children and adolescents age between 3 and 18 years who presented to the emergency room with LR-FN criteria with the exclusion of patients younger than 3 years and patients with Down syndrome. One hundred LR-FN episodes were enrolled in each arm. Patient demographics, microbiologic data, and outcomes were collected at different time points. A decision analytic model was created to compare the two treatment strategies. The outcome measures included quality-adjusted FN episodes, costs, and incremental cost-effectiveness ratios.

RESULTS

Levofloxacin was a safe and effective treatment option for LR-FN. It proved to be the dominant strategy against amoxicillin-clavulanate/ciprofloxacin with an incremental quality-adjusted life-year (QALY) of 0.0001 and a lower cost of 62.4996 Egyptian pounds (EGPs) in the treatment of home-based LR-FN with a willingness to pay a threshold of 77,520 EGPs per QALY (1 gross domestic product/capita).

CONCLUSION

For the treatment of FN in pediatric patients with cancer, levofloxacin offers a cost-saving option with improved survival benefits over a 7-day time horizon from the NCI perspective. These findings will help health care decisions regarding the allocation of health care system resources to improve supportive care for patients with LR-FN.

An evaluation of antibiotic prescription pattern and drug rationality analysis among outpatients at public health setting, India

BACKGROUND

Antibiotic resistance (AMR) is a significant worldwide health problem, with inappropriate antibiotic prescription being a major contributing factor. Prudent antibiotic use is essential for enhancing health outcomes and reducing AMR. This study assesses antibiotic prescribing practices and their logic in a public community health facility catering to 12,900 urban and rural populations in North India.

METHODS

Cross-sectional research was performed from August 2021 to August 2022, examining 1219 outpatient antibiotic prescriptions. The data encompassed medication kind, dose, duration, adherence to therapeutic criteria, and rationale evaluated by ID specialists and clinical pharmacologists. The evaluation was conducted in accordance with standard procedures, including those from NCDC and PGIMER. Demographics, antibiotic classifications, WHO AWaRe categories, diagnoses, and compliance with the essential drug list (EDL) were evaluated.

RESULTS

The results indicated that 45.9 % of prescriptions were for males and 54 % for females, predominantly involving individuals aged 20-40 years. Amoxicillin + clavulanic acid (27.2 %) was the most often given antibiotic, followed by metronidazole (13.4 %) and azithromycin (10.3 %). The WHO AWaRe categorization revealed that 49.7 % of antibiotics were categorized as "Access," 27.3 % as "Watch," and none as "Reserve." An examination of rationality indicated that 57 % of urinary tract infection prescriptions were justified, but just 29 % of respiratory tract infection prescriptions were deemed logical. Diarrhea and respiratory tract infections were recognized as primary targets for minimizing superfluous antibiotic consumption.

CONCLUSION

The research underscores the necessity for enhanced antibiotic prescription protocols in outpatient environments. Specialized education for healthcare professionals, improved prescription oversight, and compliance with evidence-based protocols are essential for fostering judicious antibiotic utilization and addressing AMR.

Antibacterial Activity of Ocimum tenuiflorum against Drug Resistant Bacteria Isolated from Raw Beef

Recent empirical evidence has acknowledged raw meat, particularly beef, as a significant reservoir for diverse foodborne pathogens and drug-resistant strains, posing severe threat to consumer health. This study aimed to isolate and identify drug-resistant bacteria from raw beef samples, obtained from different butcher shops in Khulna city, Bangladesh, as well as, to determine their susceptibility pattern against Ocimum tenuiflorum extracts. Raw beef samples were randomly collected from various butcher shops, followed by the initial isolation of thirty pure bacterial isolates. Later, 16S rRNA gene amplification and analysis identified twelve distinct bacterial species from those isolates. The antimicrobial susceptibility test results revealed ten of the isolates, including Klebsiella pneumoniae, Aeromonas veronii and Enterobacter hormaechei, to exhibit multidrug resistance pattern. Amoxicillin, nitrofurantoin, and flucloxacillin were found to be ineffective against most isolates. However, the ethanolic extracts of O. tenuiflorum were found effective in inhibiting the growth of eight species at three different concentrations. Subsequent HPLC analysis of O. tenuiflorum reported the presence of five secondary metabolites epicatechin, syringic acid, rutin hydrate, p-coumaric acid, and myricetin as potent contributors to the observed antimicrobial activity. Lastly, in silico binding interaction simulations of the secondary metabolites against five relevant targets predict syringic acid and myricetin to have effective antibacterial properties, primarily mediated by better binding affinity and molecular interactions. Thus, this study identified diverse drug-resistant bacteria in raw beef and provided novel insights into the antibacterial properties of O. tenuiflorum extracts.

Prospective comparison of the digestive tract resistome and microbiota in cattle raised in grass-fed versus grain-fed production systems

Most antimicrobials sold in the United States are used in food animals. Farm management practices contribute to antibacterial resistance (AR). Controversially, grass-fed diets have been recommended over grain-fed diets to reduce AR in beef cattle. Ionophore feed additives (non-therapeutic antibiotics that enhance feed efficiency) may contribute to AR development. We used shotgun metagenomic sequencing of fecal swabs to prospectively compare the cattle gastrointestinal resistome and microbiota in two different production systems over five periods from pre-weaning to pre-harvest. Cattle were grass-fed and pasture-raised (system A, n = 33) or grain-fed with ionophore additives in feedlots (system B, n = 34). System A cattle averaged 639 lb and 22.8 months of age, and system B cattle averaged 1,173 lb and 12.4 months of age preharvest. In total, 367 antibiotic resistance genes (ARGs) and 329 bacterial species were identified. The resistome of system A cattle had higher alpha diversity than system B cattle over their lifespan (P = 0.008). Beta-diversity estimates indicated overlap in the pre-weaning resistome and microbiota in both systems, which diverged post-weaning, with increases in several medically important ARGs when system B cattle transitioned to a grain diet. Analysis of compositions of microbiomes with bias correction indicated that levels of tetracycline, macrolide, aminoglycoside, beta-lactam, and bacitracin ARGs were significantly higher in system B cattle pre-harvest. Resistome changes were highly correlated with bacterial community changes (Procrustes, M2 = 0.958; P = 0.001). Potentially modifiable farm management strategies, including diet and ionophores, may influence abundance and diversity of ARGs in fecal samples from cattle.IMPORTANCEAntibiotic resistance is a One Health threat. More antibiotics are used in agriculture than in human medicine. We compared the relative abundance of antibiotic resistance genes (ARGs) and bacterial species in cattle raised in two different cattle production systems (grass- and grain-fed). Fecal swab samples were collected at five time points spanning pre-weaning and prior to harvest. The antibiotic resistance gene and bacterial communities were relatively similar in the pre-weaning period when cattle in both systems were milking and on pasture. Resistance genes and bacterial communities diverged post-weaning when system B cattle were given a grain diet with feed additives for growth promotion containing non-medically important antibiotics (i.e., ionophores). The levels of medically important ARGs (e.g., macrolides) increased in system B grain-fed cattle post-weaning and were higher than in system A just prior to slaughter. These data provide additional evidence that farm management strategies impact the level of antibiotic resistance.

The effects of gamma-aminobutyric acid on growth performance, diarrhoea, ruminal fermentation, and antioxidant capacity in pre-weaned calves

The pre-weaning phase is a vital period for the growth and development of calves, significantly impacting their future health and productivity. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the mammalian central nervous system that lowers blood pressure, stimulates feed intake, and enhances antioxidant capability. Gamma-aminobutyric acid has been proven beneficial for adult cows, while little research has been conducted on calves. Therefore, this study examined the effects of GABA on growth performance, diarrhoea, ruminal fermentation, and antioxidant capacity in pre-weaned Holstein calves. Ninety male Holstein calves were allocated to five groups: 0 mg/d (G0), 25 mg/d (G25), 50 mg/d (G50), 100 mg/d (G100), and 200 mg/d (G200). The experiment was conducted from 11 to 75 days of calves age, and the calves were weaned at 75 days of age. Growth performance indicators, ruminal fluid, faecal score, and serum were collected at 11, 28, 42, 60, and 75 days of calves' age. The results showed that adding GABA positively affected average daily gain and body height, with no effects on diarrhoea frequency. All dosages significantly reduced acetate and total volatile fatty acid levels in ruminal fermentation, with butyrate showing a complex response at higher doses. Overall, we recommended 100 mg/d as the optimal GABA supplementation level to improve growth performance and regulate the ruminal fermentation of pre-weaned calves before weaning.

Seven-year change of prevalence, clinical risk factors, and mortality of patients with carbapenem-resistant Klebsiella pneumoniae bloodstream infection in a Chinese teaching hospital: a case-case-control study

Carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) is a major public health threat worldwide. CRKP-BSI is associated with poor outcomes, elevated morbidity and mortality, and high healthcare costs. Therefore, the identification of risk factors for CRKP-BSI and mortality are critical for preventing and controlling CRKP in hospitals. This retrospective case-case-control study was conducted at General Hospital of Tianjin Medical University, a tertiary teaching hospital, from 2017 to 2023. It included 105 patients with CRKP-BSI (case group 1) and matched 105 patients with carbapenem-susceptible K. pneumoniae bloodstream infection (CSKP-BSI) (case group 2). The control group was selected at a ratio of 1:1:1 (case group 1: case group 2: control) from patients with a positive blood culture (except for K. pneumoniae infection) to analyze risk factors associated with the two case groups and compare the 30-day survival curves using multivariable logistic regression and Kaplan-Meier analyses. Multivariate analysis revealed that liver disease was a risk factor for K. pneumoniae-BSI, and exposure to carbapenem [odds ratio (OR) = 3.24], tigecycline (OR = 3.43), and glucocorticoids (OR = 4.64) were independent risk factors for CRKP-BSI. The 30-day mortality of the CRKP-BSI group was 30.5%, and patient groups, respiratory diseases (HR = 3.52), use of 3rd-generation cephalosporins (HR = 1.92), mechanical ventilation (HR = 2.14), and central venous catheter insertion (HR = 2.85) were independent risk factors, whereas a shorter length of hospitalization was a protective factor for 30-day mortality. The in-hospital mortality in the CRKP-BSI group was 55.2%, and arterial catheter use (OR = 3.76) was an independent risk factor for in-hospital mortality. Several factors were identified to contribute to the development of CRKP-BSI. CRKP isolates were resistant to most antibiotics. Reducing CRKP-BSI-related mortality requires comprehensive consideration of underlying diseases, judicious antibiotic use, and invasive procedures. The high morbidity, mortality, along with the limited therapeutic options for CRKP-BSI, underscore the need for improved detection, identification of risk factors to develop effective preventive measures, and development of novel agents with reliable clinical efficacy against CRKP.

Characterization of a multidrug-resistant hypovirulent ST1859-KL35 klebsiella quasipneumoniae subsp. similipneumoniae strain co-harboring tmexCD2-toprJ2 and blaKPC-2

OBJECTIVES

The rise of multidrug-resistant (MDR) Klebsiella pneumoniae is a significant public health threat. Klebsiella quasipneumoniae is often misidentified as K. pneumoniae, and its genetic and virulence traits remain underexplored. This study characterizes the genomic and phenotypic features of a K. quasipneumoniae subsp. similipneumoniae strain (KP24).

METHODS

Antibiotic susceptibility was tested using microbroth dilution assay. Virulence was evaluated through serum killing assay and Galleria mellonella infection model. Whole genome sequencing (WGS) and bioinformatics analysis determined sequence typing, resistance profiles, and plasmid types. Conjugation assays assessed plasmid transferability, while phylogenetic analysis explored genetic relationships.

RESULTS

KP24 exhibited an MDR phenotype, including resistance to carbapenems, ceftazidime/avibactam, and tigecycline. KP24 showed significantly higher serum survival and G. mellonella lethality than ATCC700603, though it was less virulent than the hypervirulent strain NUTH-K2044. WGS identified KP24 as ST1859 and KL35, harboring the aerobactin virulence gene cluster (iucABCDiutA) and multiple resistance genes, including tmexCD2-toprJ2, blaKPC-2, blaOXA-10, blaIMP-4, and qnrS1. Notably, the tmexCD2-toprJ2 and blaKPC-2 genes were located on the same plasmid (pKP24-1), an uncommon co-existence. Conjugation assays confirmed the independent transferability of pKP24-1 to Escherichia coli J53. Phylogenetic analysis revealed that ST1859 forms a distinct monoclade with low genetic diversity, closely related to ST334, suggesting regional expansion and potential global dissemination.

CONCLUSIONS

KP24 represents a hypovirulent yet multidrug-resistant strain of K. quasipneumoniae subsp. similipneumoniae, with a concerning combination of virulence and resistance determinants. The co-location of tmexCD2-toprJ2 and blaKPC-2 on a transferable plasmid highlights the potential for horizontal gene transfer of critical resistance mechanisms.

Staphylococcus borealis causing subclinical mastitis in dromedary camels

Recent studies revealed increasing incidence of udder infections caused by Coagulase Negative Staphylococci (CNS) in dairy cattle, though studies in dromedary camel are meagre. The present report describes sub-clinical mastitis in two dromedary camels caused by Staphylococcus borealis, a recently recognized udder pathogen in cattle. The bacterium was identified on the basis of morphological and biochemical characteristics, MALDI-TOF MS analysis, 16s rRNA sequencing and BLAST. Phylogenetic analysis was also performed. The isolate was submitted to National Centre for Veterinary Type Cultures, Hisar, India. The bacterium showed varying biochemical reactions as compared to bovine and human isolates. The bacterium has high antibiotic sensitivity perhaps due to less use of antibiotics in treatment of different diseases in camel. To our knowledge, this is the first report indicating Staphylococcus borealis as a cause of subclinical mastitis in dromedary camel.

Investigating the environmental fate of active pharmaceutical compounds in a coastal lagoon using a multimedia level III fugacity model

The use of active pharmaceutical ingredients (APIs) has enhanced life quality and longevity but poses significant environmental risks to ecosystems and human health. Evidence-based risk assessments are essential for addressing these issues, requiring detailed data on API presence, behavior, and effects in the environment. In particular, predictive exposure models offer a cost-effective tool to support such investigations. This study focuses on the application of a multimedia level III fugacity model to estimate the predicted environmental concentrations (PECs) and to simulate transport, distribution, and persistence of nine APIs in the Venice Lagoon (Italy), a transitional environment subjected to multiple anthropogenic stressors. Concentrations of the studied APIs in water were estimated within one order of magnitude of measured data, while the model underestimated the concentration of azithromycin and 17-β-estradiol in the sediments due to water half-life overestimation and lack of information about unmonitored emission sources. In detail, the highest levels of APIs in the water were estimated for amoxicillin and clarithromycin, while sediments showed a significant presence of azithromycin and ciprofloxacin. Model results also showed the possibility for sediments to act as sink for azithromycin, ciprofloxacin, erythromycin, estrone, and 17-β-estradiol. For all target APIs, degradation in the water column and adjective outflow were the most important elimination processes, while degradation in the sediments was significant only for erythromycin, ciprofloxacin, and clarithromycin. Monte-Carlo uncertainty and sensitivity analysis showed that degradation in water, affinity to organic matter, and sediment dynamics were the parameters with the strongest influence on model's results. Overall, this work provided valuable information on the environmental fate and behavior of the investigated APIs in a complex transitional waterbody such as the Venice Lagoon and can be useful to support future environmental risk assessments as well as studies to evaluate the effects of emission control measures (e.g., restriction of use, substitution, or implementation of new technologies for wastewater treatment) on APIs environmental exposure.

Multiplex Real-Time Polymerase Chain Reaction and Recombinase Polymerase Amplification: Methods for Quick and Cost-Effective Detection of Vancomycin-Resistant Enterococci (VRE)

Background/Objectives: Vancomycin-resistant enterococci (VRE) are one of the leading causes of antibiotic-resistant infections in the hospital setting worldwide, and this has become a major issue, because most patients infected with this strain are difficult to treat. Multiplex real-time polymerase chain reaction (RT PCR) is an advantageous technique that can amplify multiple targets in a single reaction, and can be used to quickly detect specific targets in VRE within two hours, starting from suspected colonies of bacterial cultures, without sample preparation. Methods: In this study, we selected the glycopeptide/vancomycin resistance genes that are most common in clinical settings, vanA and vanB, in combination with the species markers ddl_faecium and ddl_faecalis for the most common VRE species-Enterococcus faecium and Enterococcus faecalis. Results: DNA from forty clinical VRE strains was prepared using a fast and economic heat lysis method, and a multiplex real-time PCR assay was optimized and carried out subsequently. The results were in concordance with the results from recombinase polymerase amplification (RPA) of the same VRE samples. Conclusions: Multiplex RT PCR and RPA for VRE detection proffers a second method for the confirmation of vancomycin resistance, and it can be developed as a fast screening assay for patients before admission into high-risk settings.

Factors influencing health promotion behavior on puerperal sepsis among postpartum mothers

Puerperal sepsis is accountable for maternal death worldwide. The health promotion behaviour of postpartum mothers may contribute to preventing puerperal sepsis, which would promote maternal health. The study aims to identify the factors influencing health promotion behaviour on puerperal sepsis among postnatal mothers. A descriptive correlational study design was conducted among 112 postpartum women conveniently selected from Dhaka Medical College Hospital. The measures were personal characteristics questionnaire, perceived benefits questionnaire, perceived barrier, postpartum social support and puerperal sepsis preventive behaviour questionnaire. Data were collected and analyzed by the researcher using descriptive and inferential statistics. Descriptive statistics describe descriptive variables, such as mean, SD, frequency, and percentage. The inferential statistics Pearson's correlation, t-test, and ANOVA were used to describe the relationship among study variables. The mean age of participants was 25.4(SD = 5.14) years old. The socio-demographic characteristics of income (r = 0.24, p = 0.01)., residence (t= -2.12, p = 0.001) and ANC (t= -3.28; p = 0.001) visits were associated with puerperal sepsis preventive behaviour. In addition, the perceived benefit was positively associated (r = 0.62; p = 0.001) with puerperal sepsis preventive behaviour and the perceived barrier was found to be negatively correlated (r=-0.55, p = 0.001). The study findings help increase postpartum mothers' awareness about the benefits of puerperal sepsis preventive behaviour. Findings may be recommended for further experimental study to develop and assess the effect of health promotion guidelines on puerperal sepsis.

Antimicrobial Stewardship Impact on Antibiotic Use in Three Tertiary Hospitals in Zambia: A Comparative Point Prevalence Survey

Introduction: Antimicrobial stewardship (AMS) can improve the rational use of antibiotics in hospitals. This study assessed the impact of a multifaceted AMS intervention on antibiotic use and prescribing patterns at three tertiary hospitals in Zambia. Methods: Point Prevalence Surveys (PPS) were conducted in three tertiary hospitals in August 2022 and in October 2023. It was part of a 3-year AMS demonstration project that aimed to optimize the use of antibiotics in treating urinary tract infections (UTIs) and bloodstream infections (BSIs) in various health sector settings in Zambia. Up to 170 medical records in 2022 and 265 in 2023 were included in the assessment. Results: Overall, the prevalence of antibiotic use in this PPS was 75%. Eighty-one percent (81%) and 71% of patients assessed were on at least one antibiotic in 2022 and 2023, respectively, indicating a decrease of 10%. Similarly, prescribing ceftriaxone, the most prescribed antibiotic, declined from an average of 48% in 2022 to 38% in 2023. Adherence to Standard Treatment Guidelines (STGs) slightly increased from 42% in 2022 to 45% in 2023. Additionally, antibiotic prescribing was reduced from 1.38 to 1.21. Conclusions: Antimicrobial stewardship had an early positive impact on antibiotic use and adherence to Standard Treatment Guidelines.

Enhanced suppression of Stenotrophomonas maltophilia by a three-phage cocktail: genomic insights and kinetic profiling

Stenotrophomonas maltophilia is an understudied, gram-negative, aerobic bacterium that is widespread in the environment and increasingly a cause of opportunistic infections. Treating S. maltophilia remains difficult, leading to an increase in disease severity and higher hospitalization rates in people with cystic fibrosis, cancer, and other immunocompromised health conditions. The lack of effective antibiotics has led to renewed interest in phage therapy; however, there remains a great need for well-characterized phages, especially against S. maltophilia. In response to an oncology patient with a sepsis infection, we collected 18 phages from Southern California wastewater influent that exhibit different plaque morphology against S. maltophilia host strain B28B. We hypothesized that, when combined into a cocktail, genetically diverse phages would give rise to distinct lytic infection kinetics that would enhance bacterial killing when compared to the individual phages alone. We identified three genetically distinct clusters of phages, and a representative from each group was further investigated and screened for potential therapeutic use. The results demonstrated that the three-phage cocktail significantly suppressed bacterial growth compared with individual phages when observed for 48 h. We also assessed the lytic impacts of our three-phage cocktail against a collection of 46 S. maltophilia strains to determine if a multi-phage cocktail has an expanded host range. Our phages remained strain-specific and infected >50% of tested strains. In six clinically relevant S. maltophilia strains, the multi-phage cocktail has enhanced suppression of bacterial growth. These findings suggest that specialized phage cocktails may be an effective avenue of treatment for recalcitrant S. maltophilia infections resistant to current antibiotics.

Prolonged Exposure to Environmentally Relevant Concentrations of Chlorine Induces Heritable Antimicrobial Resistance in Disinfection Residual Pseudomonas aeruginosa

Chlorination, a crucial step in pathogen control, raises concerns due to the potential residual chlorine presence during water treatment and sanitation. However, the consequences of prolonged exposure to environmentally relevant chlorine concentrations on antimicrobial resistance (AMR) evolution and its driving mechanism in bacteria remain unclear. Therefore, this study utilized a combination of phenotypic and genotypic analyses, revealing that chlorination at concentrations of 0.2-0.4 mg/L induced enduring cross-resistance to both chlorine and multiple antibiotics (β-lactams, tetracyclines, sulfonamides, and chloramphenicol) in Pseudomonas aeruginosa after 3 days of exposure. Both Escherichia coli and P. aeruginosa exhibited outer membrane (OM) damages, evidenced by adenosine triphosphate and reactive oxygen species, though P. aeruginosa displayed stepwise OM resilience over prolonged exposure. Transcriptomic analyses of resistant P. aeruginosa unveiled heightened metabolic activity and a reinforced OM barrier after exposure. Weighted gene coexpression network analysis highlighted the pivotal role of a fortified bacterial OM, featuring activated efflux systems and modified lipopolysaccharides, in developing cross-resistance. Overexpression and mutation in mexXY-OprM and muxABC-OpmB efflux systems, along with reduced membrane electronegativity, confirmed that hereditary genetic adaptation drove AMR evolution. This study provides valuable insights into potential strategies for mitigating AMR evolution under residual chlorine disinfection.

Development of a Weighted-Incidence Syndromic Combination Antibiogram (WISCA) to guide empiric antibiotic treatment for ventilator-associated pneumonia in a Mexican tertiary care university hospital

BACKGROUND

Ventilator-associated pneumonia (VAP) is a significant nosocomial infection in critically ill patients, leading to high morbidity, mortality, and increased healthcare costs. The diversity of local microbiology and resistance patterns complicates the empirical treatment selection. The Weighted-Incidence Syndromic Combination Antibiogram (WISCA) offers an innovative tool to optimize empirical antibiotic therapy by integrating local microbiological data and resistance profiles.

OBJECTIVE

To develop a WISCA tailored for VAP in a Mexican tertiary care university hospital, aiming to enhance empirical antibiotic coverage by addressing the unique pathogen distribution and resistance patterns within the institution.

METHODS

This retrospective study included 197 VAP episodes from 129 patients admitted to a critical care unit between June 2021 and June 2024. Clinical and microbiological data, including pathogen susceptibility profiles, were analyzed using a Bayesian hierarchical model to evaluate the coverage of multiple antibiotic regimens. We also assessed the current impact of inappropriate empiric or directed treatment on in-hospital mortality using Cox regression models to support the development of a WISCA model.

RESULTS

The median age of the patients was 44 years (IQR 35-56), with Acinetobacter baumannii (n = 71), Enterobacterales (n = 53) and Pseudomonas aeruginosa (n = 36) identified as the most frequently isolated pathogens. The developed WISCA models showed variable coverage based on antibiotic regimens and the duration of invasive mechanical ventilation (IMV). Inappropriate directed therapy during the VAP episode was associated with increased mortality, as were the diagnosis of Acute Respiratory Distress Syndrome (ARDS) and a high Sequential Organ Failure Assessment (SOFA) score (p < 0.01).

CONCLUSIONS

The tailored WISCA with Bayesian hierarchical modeling provided more adaptive, subgroup-specific estimates and managed uncertainty better compared to fixed models. The implementation of this WISCA model demonstrated potential to optimize antibiotic strategies and improve clinical outcomes in critically ill patients in our hospital.

TOPIC

Optimizing Empirical Antibiotic Therapy for Ventilator-Associated Pneumonia Using a Weighted-Incidence Syndromic Combination Antibiogram in a Mexican Tertiary Care Hospital.

Harnessing bacterial antimicrobial peptides: a comprehensive review on properties, mechanisms, applications, and challenges in combating antimicrobial resistance

Antimicrobial resistance (AMR) is a significant global health concern due to the persistence of pathogens and the emergence of resistance in bacterial infections. Bacterial-derived antimicrobial peptides (BAMPs) have emerged as a promising strategy to combat these challenges. Known for their diversity and multifaceted nature, BAMPs are notable bioactive agents that exhibit potent antimicrobial activities against various pathogens. This review explores the intricate properties and underlying mechanisms of BAMPs, emphasizing their diverse applications in addressing AMR. Additionally, the review investigates the mechanisms, analyses the challenges in utilizing BAMPs effectively, and examines their potential applications and associated deployment challenges providing comprehensive insights into how BAMPs can be harnessed to combat AMR across different domains. The significance of this review lies in highlighting the potential of BAMPs as transformative agents in combating AMR, offering sustainable and eco-friendly solutions to this pressing global health challenge.