Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis. 2010;10:597-602. [PMID: 20705517 PMCID: PMC2933358 DOI: 10.1016/s1473-3099(10)70143-2]

Investigating the impact of fecal contamination on antibiotic resistance genes in urban environments using host-associated molecular indicators

Antibiotic resistome of gut microbiota can be transmitted into the urban ecosystems via fecal pollution, potentially leading to a public health crisis. It is essential to determine the primary sources of fecal contamination and accurately evaluate the health risks for the propagation of antibiotic resistance genes (ARGs) from the intestinal microbiota. In this research, the occurrence, sources and potential hosts of ARGs in urban environmental samples collected from a wastewater treatment plant (WWTP), natural water bodies, tap water and farmland soil were comprehensively investigated. Host-associated fecal indicators for general warm-blooded animals (BacGeneral), humans (crAssphage), and other animals (bovines and swine) were employed for reliable microbial source tracking (MST). Results showed that the fecal indicator BacGeneral was detected in 84.00 % of collected environmental samples, indicating the widespread fecal contamination in local water and farmland. The WWTP was the reservoir and main source of fecal contamination in local environment, harboring the highest total abundances of ARGs (3.85 ± 2.72 ARGs/16S rRNA) and mobile genetic elements (MGEs) (0.32 ± 0.12 MGEs/16S rRNA) from multiple animals and humans. Although the swine-associated indicator was undetected, fecal contamination from both bovines and humans was prevalent in collected samples, with detection rates of pollution indicators at 52.00 % for bovine and 28.00 % for human sources. The co-occurrence of ARGs, fecal indicators and MGEs was analyzed, and significant correlation (P < 0.01) between total ARG abundance and fecal indicator (BacGeneral) in contaminated environments demonstrated that fecal pollution exhibited a great influence on overall resistome in local environment. This research offers a comprehensive understanding of the sources and dissemination of ARGs in feces-polluted urban environments, providing data for the monitoring and prevention of ARG pollution.

Antibiotic resistance genes in Escherichia coli - literature review

Antimicrobial resistance threatens humans and animals worldwide and is recognized as one of the leading global public health issues. Escherichia coli (E. coli) has an unquestionable role in carrying and transmitting antibiotic resistance genes (ARGs), which in many cases are encoded on plasmids or phage, thus creating the potential for horizontal gene transfer. In this literature review, the authors summarize the major antibiotic resistance genes occurring in E. coli bacteria, through the major antibiotic classes. The aim was not only listing the resistance genes against the clinically relevant antibiotics, used in the treatment of E. coli infections, but also to cover the entire resistance gene carriage in E. coli, providing a more complete picture. We started with the long-standing antibiotic groups (beta-lactams, aminoglycosides, tetracyclines, sulfonamides and diaminopyrimidines), then moved toward the newer groups (phenicols, peptides, fluoroquinolones, nitrofurans and nitroimidazoles), and in every group we summarized the resistance genes grouped by the mechanism of their action (enzymatic inactivation, antibiotic efflux, reduced permeability, etc.). We observed that the frequency of antibiotic resistance mechanisms changes in the different groups.

Genome-based assessment of antimicrobial resistance of Escherichia coli recovered from diseased swine in eastern China for a 12-year period

The global rise of antimicrobial resistance (AMR), driven by antibiotic use in healthcare and agriculture, poses a major public health threat. While AMR in clinical settings is well studied, there is a gap in understanding the resistance profiles of Escherichia coli from diseased livestock, particularly regarding zoonotic transmission. This study analyzes 114 E. coli isolates from diseased swine over 12 years, revealing that 99.12% were multidrug-resistant. Resistance was highest for ampicillin and amoxicillin/clavulanic acid (100%), followed by ciprofloxacin (96.49%) and tetracycline (94.74%). Furthermore, 21.05% of isolates were resistant to colistin, and 1.75% to tigecycline. A total of 76 antimicrobial resistance genes (ARGs) were identified, with mcr-1 found in 18.42%, mcr-3 in 4.39%, and tet(X4) in 1.75%. Significant co-occurrence of ARGs and plasmids suggests potential for co-selective dissemination. This study is the first to report enterotoxigenic E. coli (ETEC) strains carrying both mcr-1 and mcr-3 genes. After the 2017 colistin ban in China, mcr-1 detection rates significantly decreased, while florfenicol resistance rates increased in 2018-2021 (94.29%) compared to 2010-2017 (79.55%). This work provides valuable insights into the AMR profiles of E. coli from diseased swine and highlights trends that can inform strategies for monitoring and controlling public health risks associated with zoonotic E. coli transmission.IMPORTANCEThis study highlights the critical role of diseased and deceased swine in the spread of antimicrobial resistance (AMR), providing new insights into the transmission of resistance genes in zoonotic contexts. By analyzing E. coli from diseased swine, we identify key resistance genes such as mcr-1, mcr-3, and tet(X4), which pose significant public health risks, especially regarding last-resort antibiotics like colistin. Moreover, the study identifies novel transmission patterns of mcr genes, including ETEC strains carrying the mcr-3 gene and strains harboring both mcr-1 and mcr-3 genes. The role of plasmids in horizontal gene transfer is also revealed, facilitating rapid AMR spread across species. The long-term persistence of resistant strains highlights the challenges in controlling AMR in livestock. These findings underscore the need for enhanced surveillance and a One Health approach to mitigate AMR risks across animal, human, and environmental health.

Loss of OprD function is sufficient for carbapenem-resistance-only but insufficient for multidrug resistance in Pseudomonas aeruginosa

BACKGROUND

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) constitutes a serious source of global healthcare-associated infections, and the exploration of its resistance mechanism represents an important approach to address this issue. Because current research on antibiotic resistance predominantly focuses on multidrug-resistant P. aeruginosa which is widely isolated clinically and the resistance mechanism is complicated. CRPA generally has a higher tolerance to other antibiotics than carbapenem-sensitive P. aeruginosa, yet the specific mechanism of resistance remains poorly understood.

RESULTS

This study delves into the specific antibiotic resistance mechanisms of carbapenem-resistance-only P. aeruginosa (CROPA), a rare kind of pathogen that shows resistance exclusively to carbapenem antibiotics. We collected 11 clinical isolates of CROPA, performed genome sequencing. Our analysis revealed numerous amino acid mutations and premature termination of OprD expression in the CROPA strains. The insertion of IS256 element into OprD in P. aeruginosa was a novel finding. Validation via qPCR and SDS-PAGE affirmed diminished OprD expression levels. Interestingly, common carbapenemases were not detected in our study, and there was no observed upregulation of relevant efflux pumps. The expression of wild-type OprD in CROPA strains restored the sensitivity to carbapenem antibiotics.

CONCLUSIONS

Compared with previous studies on MDR-CRPA, the emergence of CROPA may be directly linked to changes in OprD, while other resistance mechanisms could contribute to broader antibiotic resistance profiles. By focusing on the antibiotic resistance mechanisms of CROPA, this study illuminates the relationship between specific antibiotic resistance mechanisms and antibiotic resistance, providing a theoretical foundation for guiding clinical treatment and developing novel anti-infective agents.

Prevalence of New Delhi Metallo-β-lactamase (blaNDM) gene in a selected population of drug-resistant clinical isolates

OBJECTIVES

Drug-resistant Enterobacterales carrying carbapenem-resistant genes cause severe infections in clinical settings worldwide. Among these, the New Dehli Metallo-β-lactamase (blaNDM) gene is significantly prevalent and associated with high morbidity. This study was designed to investigate the susceptibility profiling of Carbapenem-Resistant-Enterobacterales (CRE), prevalence of blaNDM and its variants, and associated risk factors.

METHODS

CRE isolates from a tertiary care hospital, in Islamabad, Pakistan, were identified and the susceptibility testing was performed using disc diffusion method. MICs were determined for imipenem, tigecycline, and colistin through E-strips and microbroth dilution method respectively. For molecular characterization and typing of the blaNDM gene, PCR products were sequenced, and the phylogenetic analysis was performed using MEGA ver 6.0 software.

RESULTS

Among 5,134 clinical samples, 42.13% (n = 2,163) yielded pathogens including 42.58% (n = 921) Enterobacterales. On further screening, 39.52% (n = 364) of Enterobacterales were identified as CRE. The blaNDM gene was detected in 75.27% (n = 274) in CRE isolates, comprising blaNDM-1 (44%), blaNDM-5 (53%), and blaNDM-7 (3%) variants. Tigecycline (86.7%) and colistin (100%) were most effective antimicrobial agents with MICs ranging from 0.064 to 8 and 0.125-1 µg/ml respectively. blaNDM-1-harboring bacteria exhibited high antimicrobial resistance compared to blaNDM-5 and blaNDM-7. Cefiderocol was 75.6% and ceftazidime/avibactam with aztreonam was 97.08% effective against blaNDM-harboring bacteria. The phylogenetic analysis indicated that blaNDM variants showed close genetic relationships and homology to the previously described sequences in GenBank databases having diverse connection with worldwide sequences.

CONCLUSION

The high prevalence of blaNDM in our study has of great concern for clinical practice and public health. Clinicians are left with few therapeutic options. However, ceftazidime/avibactam with aztreonam may show therapeutic success. Continuous surveillance is crucial to monitorgenetic variations of continuously evolving blaNDM gene, which is essential for effective clinical management.

Discovery of Conformationally Constrained Dihydro Benzo-Indole Derivatives as Metallo-β-Lactamase Inhibitors to Tackle Multidrug-Resistant Bacterial Infections

The discovery of metallo-β-lactamase (MBL) inhibitors is crucial in the fight against bacterial infections following the emergence and rapid spread of New Delhi metallo-β-lactamase-1 (NDM-1), as well as clinically relevant Verona integrin-encoded metallo-β-lactamase (VIM), and Imipenemase (IMP). The situation is alarming as there are insufficient antibiotics in the pipeline to combat critical multidrug-resistant infections. Here, we report the discovery of novel dihydrobenzo-indole (dBI) derivatives as a new class of potent metallo-β-lactamase inhibitors (MBLIs) by applying scaffold hopping, conformation constrained, and substituent-decorating strategies. Among them, compound 17u exhibited the best inhibitory activity against MBL with acceptable physicochemical and ADME properties. 17u exhibited remarkable enhancement of carbapenems' effectiveness against a range of MBL-producing clinical strains. This efficacy extended to in vivo settings when combined with the imipenem antibiotic, significantly reducing the bacterial load in a thigh infection model. Consequently, it qualifies as a prime candidate for further development as an MBLI.

The spread of CTX-M-type extended-spectrum beta-lactamases in China: Epidemiology and evolutionary analyses

CTX-M-type extended-spectrum beta-lactamases (ESBLs) have shown a high level of global transmission, with limited systematic understanding of their epidemic patterns in China. A comprehensive analysis covering 1974-2023 identified 133 (3.2%) blaCTX-Ms-producing strains among 4146 strains from 25 Chinese cities across 82 genera were performed. Integrating with public database strains (n=431), the study comprised 564 blaCTX-Ms-positive isolates sourced from 19 provinces (1986-2022) including 300 (53.2%) clinical and 228 (40.4%) environmental blaCTX-Ms. The most frequent sources of infection were diarrhea (44%), upper respiratory tract infection (22.2%) and urinary tract infection (14%). Phylogenetic studies indicated CTX-M-1 and CTX-M-9 emerged as the predominant subgroups. Lineages exhibited diverse mutation sites without being restricted by geographical conditions. Ka/Ks ratio distribution varied significantly among lineages (P<0.05). Lineages 1 (L1) and L2 were characterized by neutral or purifying selection, whereas L3 was mainly under purifying selection. Adaptive evolution was noted at different loci within each lineage. The influence of geographic distance on phylogeny varied distinctly across different lineages. Notably, for Lineage L3, there was a remarkably strong correlation observed, which implies that human activities exerted a more substantial influence on genetic distances compared to geography. This research provides valuable insights into the epidemiology, genotypic diversity, and evolutionary traits of blaCTX-Ms in China, supporting health risk assessment for early warning systems.

Revisiting therapeutic options against resistant klebsiella pneumoniae infection: Phage therapy is key

Multi-drug resistant and carbapenem-resistant hypervirulent Klebsiella pneumoniae strains are spreading globally at an alarming rate, emerging as one of the most serious threats to global public health. The formidable challenges posed by the current arsenal of antimicrobials highlight the urgent need for novel strategies to combat K. pneumoniae infections. This review begins with a comprehensive analysis of the global dissemination of virulence factors and critical resistance profiles in K. pneumoniae, followed by an evaluation of the accessibility of novel therapeutic approaches for treating K. pneumoniae in clinical settings. Among these, phage therapy stands out for its considerable potential in addressing life-threatening K. pneumoniae infections. We critically examine the existing preclinical and clinical evidence supporting phage therapy, identifying key limitations that impede its broader clinical adoption. Additionally, we rigorously explore the role of genetic engineering in expanding the host range of K. pneumoniae phages, and discuss the future trajectory of this technology. In light of the 'Bad Bugs, No Drugs' era, we advocate leveraging artificial intelligence and deep learning to optimize and expand the application of phage therapy, representing a crucial advancement in the fight against the escalating threat of K. pneumoniae infections.

Co-existence of plasmid-mediated blaNDM-1 and blaNDM-5 in Escherichia coli sequence type 167 and ST101 and their discrimination through restriction digestion

The concurrent presence of multiple New Delhi metallo-β-lactamase (blaNDM) variants within an isolate often goes undetected without next-generation sequencing. This study detects and characterizes dual blaNDM variants in Escherichia coli through Sanger and whole-genome sequencing. Additionally, a rapid identification method utilizing restriction digestion was designed for detecting blaNDM variants carrying M154L mutation. Antibiotic susceptibility, minimal inhibitory concentration for meropenem and ertapenem, PCR, and Sanger sequencing of blaNDM along with genome sequencing using Illumina and Nanopore technology were conducted. Transmissibility and replicon types of blaNDM-harboring plasmids were evaluated. Restriction digestion using restriction enzyme, BtsCI was developed to distinguish between blaNDM-1 and blaNDM variants possessing M154L mutation, such as blaNDM-5, blaNDM-7 etc. Two isolates belonging to phylogroups A; ST167 and B1; ST101 and resistant to meropenem and ertapenem (≥16 mg/L) were recovered from the blood of a neonate and the rectal swab of a pregnant woman, respectively. blaNDM was detected by PCR, and Sanger sequences of blaNDM showed two peaks at 262 (G and T) and 460 (A and C) nucleotide positions indicative of more than one blaNDM variant. Hybrid assembly confirmed co-existence of blaNDM-1 and blaNDM-5 in each isolate. blaNDM-1 was located on IncY (ST167) and IncHI1A/HI1B (ST101), while blaNDM-5 was on IncFIA/FII (ST167) and IncC (ST101) plasmids in the two isolates. Digestion with BtsC1 could discriminate between blaNDM-1 and blaNDM-5. The co-existence of multiple blaNDMs, blaNDM-1, and blaNDM-5 in epidemic clones of E. coli is concerning. Restriction digestion method and Sanger sequencing can facilitate quick identification of dual blaNDM variants in a single isolate.IMPORTANCEThe global dissemination of antimicrobial resistance genes is a serious concern. One such gene, blaNDM, has spread globally via plasmids. blaNDM confers resistance against all β-lactam antibiotics, except monobactams. Most of the earlier literature reported the presence of single blaNDM variant. However, this study reports the prevalence of dual blaNDM variants (blaNDM-1 and blaNDM-5) located on two separate plasmids identified in two distinct Escherichia coli epidemic clones ST167 and ST101 isolated from a septicemic neonate and a pregnant mother, respectively. blaNDM-5 differs from blaNDM-1 due to the presence of two point mutations (i.e., V88L and M154L). This study detected dual blaNDM variants through Sanger sequences and further validated them through hybrid-genome assembly. Detection of multiple blaNDM variants in a single isolate remains difficult until genome sequencing or southern blotting is carried out. Hence, a simple restriction digestion method was devised to rapidly screen dual blaNDM variants containing M154L mutation.

A Comprehensive Overview of Klebsiella Pneumoniae: Resistance Dynamics, Clinical Manifestations, and Therapeutic Options

Klebsiella pneumoniae (Kp) is a notable pathogen responsible for various infections. The emergence of hypervirulent and carbapenem-resistant strains has raised global concern. Many novel approaches were developed to combat the current severe situation of antibiotic resistance, and clinical guidelines have also provided corresponding recommendations. This review highlights the critical aspects of Kp, including classification, virulence factors, systemic dissemination, drug resistance progression and the new therapeutic strategies to combat this evolving threat.

Beyond antibiotics: exploring multifaceted approaches to combat bacterial resistance in the modern era: a comprehensive review

Antibiotics represent one of the most significant medical breakthroughs of the twentieth century, playing a critical role in combating bacterial infections. However, the rapid emergence of antibiotic resistance has become a major global health crisis, significantly complicating treatment protocols. This paper provides a narrative review of the current state of antibiotic resistance, synthesizing findings from primary research and comprehensive review articles to examine the various mechanisms bacteria employ to counteract antibiotics. One of the primary sources of antibiotic resistance is the improper use of antibiotics in the livestock industry. The emergence of drug-resistant microorganisms from human activities and industrial livestock production has presented significant environmental and public health concerns. Today, resistant nosocomial infections occur following long-term hospitalization of patients, causing the death of many people, so there is an urgent need for alternative treatments. In response to this crisis, non-antibiotic therapeutic strategies have been proposed, including bacteriophages, probiotics, postbiotics, synbiotics, fecal microbiota transplantation (FMT), nanoparticles (NPs), antimicrobial peptides (AMPs), antibodies, traditional medicines, and the toxin-antitoxin (TA) system. While these approaches offer innovative solutions for addressing bacterial infections and preserving the efficacy of antimicrobial therapies, challenges such as safety, cost-effectiveness, regulatory hurdles, and large-scale implementation remain. This review examines the potential and limitations of these strategies, offering a balanced perspective on their role in managing bacterial infections and mitigating the broader impact of antibiotic resistance.

Epidemiology, phylogeny and genetic characterization of carbapenem-resistant Citrobacter spp. from 5 hospitals in China

OBJECTIVES

Carbapenem-resistant Citrobacter spp. (CRC) are increasingly recognized as healthcare-associated pathogens, while systematic studies on clinical epidemiology, genetic diversity, and resistant mechanisms of CRC are relatively scarce. The present study provides comprehensive and systematic research on CRC.

METHODS

Clinical isolates of Citrobacter spp. resistant to carbapenems were collected from 5 hospitals across China between October 2014 and December 2017. All the isolates were identified by MALDI-TOF MS and FastANI. Whole-genome sequencing and phylogenetic analyses were performed. Sequencing data were analyzed using MLST, PlasmidFinder, ResFinder, and ISFinder tools.

RESULTS

Thirty-one CRC isolates were isolated from 5 hospitals in different provinces. These strains exhibited significant phylogenetic divergence. ST85 (12.90%) and ST116 (12.90%) were the predominant STs. NDM (41.94%), KPC-2 (25.81%), and IMP (19.35%) were the most frequent carbapenemases of CRC. Interestingly, KPC is frequently associated with C. freundii, while NDM is predominantly observed in C. portucalensis. All the IncX3 and IncN-type plasmids carrying blaNDM and most non-typeplasmids carrying blaKPC were transferrable by conjugation. The genes blaNDM and blaKPC were primarily located within relatively conserved genomic environments, including "ISAba125-blaNDM-bleMBL-trpF-dsbD-cutA1-groES-groEL-ISCR27" and "Tn3 transposase-ISKpn27-blaKPC-2-△ISKpn6-korC-kclA-hp-hp-△repB-TnAS1".

CONCLUSIONS

The clonal transmission of CRC and the conjugative antibiotic resistance plasmids were the key mechanisms driving the spread of multidrug resistance. It highlights the need to strengthen molecular surveillance, with a focus on high-prevalence clones such as ST85 and ST116 carrying mobile resistance elements.

Development of molecular Trojan horses targeting New Delhi metallo-β-lactamase-1 for the restoration of meropenem susceptibility in drug-resistant bacteria

The emergence of New Delhi metallo-β-lactamase-1 (NDM-1) poses a significant threat to the clinical application of antibiotics, as it possesses the ability to hydrolyze nearly all β-lactam antibiotics. Regrettably, there are currently no clinical drugs targeting NDM-1, making it imperative to develop highly potent and minimally toxic NDM-1 inhibitors. Herein, a series of molecular Trojan horses targeting NDM-1 were synthesized by introducing ebselen into 7-aminocephalosporanic acid derivatives via a C-Se bond. Representative compound 18b exhibited potent inhibitory activity against NDM-1, with an IC50 value of 7.03 μM, and combining with meropenem (Mem) decreased the minimum inhibitory concentration (MIC) of Mem by 4-32-fold in NDM-1 expressing bacteria. Mechanistically, 18b released the ebselen moiety at the active site of NDM-1, forming a Se-S bond with Cys208 to achieve targeted drug delivery of ebselen. Importantly, 18b demonstrated potent inhibition of resistant bacterial growth and replication in mice when administered in combination with Mem. These results suggest that 18b is a promising candidate for treating infections caused by resistant bacteria expressing NDM-1.

Antibiotic resistance genes in anaerobic digestion: Unresolved challenges and potential solutions

Antimicrobial resistance (AMR) threatens public health, necessitating urgent efforts to mitigate the global impact of antibiotic resistance genes (ARGs). Anaerobic digestion (AD), known for volatile solid reduction and energy generation, also presents a feasible approach for the removal of ARGs. This review encapsulates the existing understanding of ARGs and antibiotic-resistant bacteria (ARB) during the AD process, highlighting unresolved challenges pertaining to their detection and quantification. The questions raised and discussed include: Do current ARGs detection methods meet qualitative and quantitative requirements? How can we conduct risk assessments of ARGs? What happens to ARGs when they come into co-exposure with other emerging pollutants? How can the application of internal standards bolster the reliability of the AD resistome study? What are the potential future research directions that could enhance ARG elimination? Investigating these subjects will assist in shaping more efficient management strategies that employ AD for effective ARG control.

Genomic nano-biosensor for rapid detection of the carbapenem-resistant gene bla NDM-1 in carbapenemase-producing bacteria

Antimicrobial resistance (AMR) has become one of the major public health concerns causing serious obstacles to the successful prevention and treatment of infectious diseases. To curb the spread of AMR, well-equipped laboratories for the early detection of disease-causing pathogens and resistant genes are crucial, something that remains unmet in developing countries due to resource constraints and inadequate infrastructure. This paper presents an affordable and simple nanoparticle-based biosensor for rapidly detecting the bla NDM-1 gene in carbapenemase-producing (CP) bacteria. The biosensor employs thiol-ligand surface functionalized gold nanoparticles (GNPs) conjugated with an oligonucleotide probe specific for detecting the bla NDM-1 gene. The biosensor was evaluated using DNA extracted from CP bacteria having the target bla NDM-1 gene, two non-NDM-1 CP bacteria, and five susceptible bacterial strains. Tuning of the localized surface plasmon resonance (LSPR) of the GNPs was achieved by reducing the surrounding pH of the GNPs, hence inducing aggregation. With the binding of GNPs-probe-target DNA, the stability of GNPs was enhanced, as confirmed by the retention of the red colour when an optimized amount of 0.1 M HCl was added to induce aggregation. The absence of target DNA was indicated by the aggregation of GNPs after the addition of acid, which resulted in a colour change from red to blue/purple and a shift in the LSPR band to a longer wavelength, averaging 620 nm. The biosensor visual detection results were quantified with absorbance spectra measurements and the results were achieved within 30 minutes. The biosensor successfully detected the target DNA from bla NDM-1 positive bacteria and distinguished the non-targets. The analytical sensitivity achieved was 2.5 ng μL-1 which corresponds to approximately 103 colony-forming units per milliliter. These findings were confirmed through PCR amplification. This nano-biosensor offers an inexpensive, simple, rapid, and sensitive method for detecting the bla NDM-1 gene in carbapenemase producers, and is readily implementable in resource-limited settings.

Navigating Antibiotic Resistance in Gram-Negative Bacteria: Current Challenges and Emerging Therapeutic Strategies

The rapid rise of antibiotic resistance poses a severe global health crisis, necessitating new approaches to counter this growing threat. The problem is exacerbated in Gram-negative bacterial pathogens as many antibiotics are unable to enter these cells owing to their unique additional outer membrane barrier. In this review, we discuss the challenges of targeting Gram-negative bacteria, including the complexity of the outer membrane, as well as the presence of efflux pumps and β-lactamases that contribute to resistance. We also review solutions proposed to facilitate the entry and accumulation of antibiotics in Gram-negative bacteria. These involve using existing antibiotics in combination with other inhibitors to attack the bacterial cell synergistically. We also highlight approaches to target Gram-negative pathogens via novel modes of action, providing new strategies to tackle antibiotic resistance.

Integrated assessment of mucilage impact on human health using the One Health approach: Prevalence and antimicrobial resistance profiles of Escherichia coli and Clostridium perfringens in the Marmara Sea, Türkiye

This study employed a One Health approach to assess the potential impact of mucilage on human health by characterizing the prevalence and antimicrobial resistance (AMR) profiles of Escherichia coli and Clostridium perfringens strains isolated during the 2021 mucilage event in the Marmara Sea, Türkiye. Mucilage, a gelatinous organic substance exacerbated by climate change, disrupts marine ecosystems by depleting oxygen, threatening biodiversity, and serving as a reservoir for pathogenic microorganisms. Surface and benthic mucilage samples collected from the Marmara Sea were analysed for AMR profiles using genome analysis, the BD Phoenix™ 100 automated system, and E-test methods. The study identified 13 E. coli and one C. perfringens strain, harboring 244 and six AMR genes from 21 and eight drug classes, respectively, along with multiple virulence factors (VFs). The E. coli strains exhibited four distinct serotypes (O138:H28 [Mu-3], O18:H49 [Mu-4], O128:H12 [Mu-35] and O101:H10 [Mu-125]), reported for the first time from Türkiye and mucilage. Notably, anaerobic microorganisms like C. perfringens thrived in mucilage, underscoring their ecological significance. Seasonal and climatic factors influencing mucilage formation amplify its role in transmitting antimicrobial-resistant pathogens, posing significant risks to public and environmental health. The findings highlight the urgent need for continuous monitoring and mitigation strategies for mucilage-related hazards.

Exploring New Delhi Metallo Beta Lactamases in Klebsiella pneumoniae and Escherichia coli: genotypic vs. phenotypic insights

BACKGROUND

Carbapenemase-producing Enterobacterales pose a serious clinical threat, particularly in high-burden settings of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae (CREK), where rapid detection tools are essential to aid patient management. In this study, we focused on blaNDM, the most frequently reported carbapenemase in the region, and evaluated a combined phenotypic (lateral flow) and genotypic (PCR and WGS) approach for its detection. This research underscores the utility of lateral flow assays as a practical alternative to resource-intensive genotypic methods, offering a scalable solution for settings with limited laboratory capacity.

METHOD

One hundred seventy-seven extensively drug-resistant strains were characterized using MALDI-TOF. Isolates were analyzed to detect Carbapenem-resistant Escherichia coli and Klebsiella pneumoniae (CREK) using disk diffusion, MIC test, and PCR targeting blaNDM. Antibiotic susceptibility patterns were analyzed and visualized using single-linkage hierarchical clustering, with results displayed on a permuted heat map. Immunochromatographic assay, RESIST-5 O.K.N.V.I (Coris Bioconcept®) was used for CREK isolates [(n = 17), positive and negative)] and Oxford Nanopore Sequencing was conducted on subsets [(n = 5) blaNDM-positive co-producers of blaNDM and blaOXA, and (n = 2) blaNDM-negative blaOXA producers) to evaluate the reliability of phenotypic and genotypic tests.

RESULT

Most of the XDR strains (90%) were CREK, with K. pneumoniae (71.2%) more prevalent than E. coli (28.7%) (p < 0.05). All CREK strains exhibited complete resistance (100%) to multiple antibiotics with 66% showing sensitivity to levofloxacin. Furthermore, K. pneumoniae (57.8%) had higher blaNDM gene prevalence than E. coli (36.9%). Among blaNDM-positive CREK, lateral flow assay revealed approximately half of each bacteria type co-produced blaOXA (E.coli, 52.9%), and (K. pneumoniae, 47%). For blaNDM-negative strains, blaOXA was more prevalent in K. pneumoniae (82.35%) than E. coli (41%) (p < 0.05). Comparing phenotypic to genotypic assays, E. coli showed 100% (CI 80.49 - 100%) sensitivity and specificity with a high Kappa agreement coefficient (0.91) (CI 95% 0.661-1, p < 0.01), whereas K. pneumoniae assays had lower sensitivity and specificity (40%) (CI 5.27 - 85.34%), with a lower Kappa agreement coefficient (0.20) (CI 95% 0.104-0.298, p < 0.01).

CONCLUSION

This study demonstrates the value of the RESIST-5 O.K.N.V.I. lateral flow assay as a rapid and reliable diagnostic tool for detecting blaNDM in Escherichia coli, with strong agreement to PCR and WGS. While performance for Klebsiella pneumoniae was lower, the assay offers a practical alternative in resource-limited settings, aiding antimicrobial stewardship and improving diagnostic capacities in high-burden regions.

Reflecting on Fleming's caveat: the impact of stakeholder decision-making on antimicrobial resistance evolution

Antimicrobial resistance poses one of the greatest and most imminent threats to global health, environment and food security, for which an urgent response is mandated. Evolutionary approaches to tackling the crisis tend to focus on proximate issues including the mechanisms and pathways to resistance, with associated calls to action for infection control and antimicrobial stewardship. This is of clear benefit but overlooks the fundamental influence of policy and stakeholder decision-making on resistance evolution. In 1945, Fleming issued a stark warning on the irresponsible use of penicillin and its potential to cause death due to penicillin-resistant infections. Attention to resistance evolution theory and heeding Fleming's advice could have allowed for a vastly different reality. Embedding evolutionary theory within policy, industry and regulatory bodies is not only essential but is now a race against time. Hence, critical appraisal of historical behaviour and attitudes at a global scale can inform a paradigm of anticipatory and adaptive policy. To undertake this exercise, we focused on the largest group of antibiotics with the greatest clinical and economic footprint, the beta-lactams. We examined historical case studies that affected how beta-lactams were developed, produced, approved and utilized, in order to relate stakeholder decision-making to resistance evolution. We derive lessons from these observations and propose sustainable approaches to curb resistance evolution. We set a position that actively incorporates an evolutionary theory of antimicrobial resistance into decision-making within antimicrobial development, production and stewardship.

Epidemiology and Genetic Traits of Carbapenemase-Producing Enterobacterales: A Global Threat to Human Health

Carbapenemase-producing Enterobacterales (CPE) represent an important threat to global health, resulting in an urgent issue in clinical settings. CPE often exhibit a multidrug-resistant (MDR) phenotype, thus reducing the antimicrobial armamentarium, with few antibiotics retaining residual antimicrobial activity against these pathogens. Carbapenemases are divided into three classes (A, B, and D) according to the Ambler classification system. Among these, KPC (class A), NDM, VIM, IMP (class B), and OXA-48-like (class D) represent the most important carbapenemases in terms of diffusion and clinical impact. CPE diffusion has been observed worldwide, with current endemicity in multiple territories around the world. In this context, the clonal spread and plasmid-mediated transmission of carbapenemases have contributed to the global spread of CPE worldwide and to the diffusion of carbapenemases among different Enterobacterales species. In recent years, novel molecules showing excellent in vitro and in vivo activity have been developed against CPE. However, the recent emergence of novel traits of resistance to these molecules has already been reported in several cases, mitigating the initial promising results. This review aims to provide an updated description of the major classes of carbapenemases, their global distribution, and future perspectives to limit the diffusion of CPEs.

Houseflies (Musca domestica) as vectors of multidrug-resistant, ESBL-producing Escherichia coli in broiler poultry farms of North India: implications for antibiotic resistance transmission

The transmission of antibiotic resistance (AR) from farm animals to healthy human communities, beyond the food chain, is often facilitated by biological vectors, notably houseflies (Musca domestica). This study aimed to evaluate the role of M. domestica collected from commercial broiler chicken farms as a carrier of multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. E. coli were isolated separately from the housefly's external surface (ES) and internal homogenate (IH) to determine the primary AR transmission route within houseflies. Remarkably, 68.6% houseflies harboured E. coli. Isolated E. coli were evaluated for susceptibility to clinically relevant antibiotics and screened for the presence of 22 plasmid-borne AR genes (ARGs) using PCR. Results revealed significant resistance to key antibiotics, with > 70% of isolates resistant to ampicillin and > 50% resistant to tetracycline and nalidixic acid in both ES- and IH-derived E. coli. Notably, a significant prevalence of resistance was observed to third-generation cephalosporins. Additionally, > 80% of E. coli isolates were MDR. A statistically significant difference (unpaired t-test, p < 0.05) was observed in the presence of ESBL-producing E. coli between the houseflies' ES (28.14%) and IH (38.14%). ARGs such as, ampC, tetA, qnrS, strA, strB, and sul3 were frequently detected in both ES- and IH-derived E. coli isolates. Among the ESBL-producing genes, blaCTX-M was the most abundant. Pearson's correlation analysis predicted the ARGs responsible for phenotypic resistance to specific antibiotics. Farm-derived flies harboured a significantly higher number of MDR E. coli (unpaired t-test, p < 0.05) than the ones isolated from flies housing a distant non-farm environment. Conclusively, this study illustrates the role of houseflies as vectors for AR transmission from AR hotspots to human communities.

Risk of Colonization with Multidrug-Resistant Gram-Negative Bacteria Among Travellers and Migrants: A Narrative Review

Globalization in the 21st century has posed several challenges. In particular, the spread of multidrug-resistant bacterial strains, especially Gram-negative bacteria, which are prevalent in certain regions of the world, is one of the most critical issues. This raises concerns about the risks associated with the booming tourism industry and migratory flows. In fact, even transient colonization with multidrug-resistant strains can present significant challenges to individual, family, and public health. Understanding the epidemiology and mechanisms of resistance, associated risk factors and prevention policies is therefore essential to ensure that strategies are in place to limit the global spread of high-risk bacterial clones and thereby protect public health.

Epidemiology and Mechanism of Drug Resistance of Multidrug-Resistant Klebsiella Pneumoniae Isolated from Patients with Urinary Tract Infection in Beijing Teaching Hospital, China

Purpose

Klebsiella pneumoniae is an important pathogenic bacterium in causing urinary tract infection. With the overuse of antibiotics, bacteria resistant to quinolones combined with carbapenems are increasing. In this study, we investigated the epidemiology, molecular characteristics, drug resistance of multidrug-resistant Klebsiella pneumoniae (MDR-KPN) isolated from urine samples. It provides theoretical basis for the treatment of urinary tract infection by clinicians.

Patients and Methods

Fifty-one strains of Klebsiella pneumonia were obtained from urine samples collected between 2012 and 2017 in total. All the strains are multi-drug resistant bacteria. This paper used multilocus sequence typing (MLST) to determine molecular epidemiological typing. We performed antimicrobial susceptibility testing and investigated quinolones and carbapenems resistance genes.

Results

The strains which we collected were resistant to ciprofloxacin and Levofloxacin. In an epidemiological analysis using MLST, 86.27% (44/51) of isolates were confirmed to be ST11. The main carbapenem resistance gene was KPC-19, 78.43(40/51). Among the quinolone resistance genes, the major resistance genes were aac(6')-Ib-cr, oqxA and oqxB.

Conclusion

The main molecular epidemiological types we detected was ST11. The main resistance gene of carbapenems was KPC-19. The quinolone resistance genes are mainly aac(6')-Ib-cr, oqxA and oqxB. The experimental results can help control the use of quinolones and carbapenems, and we could provide rational drug use basis for clinicians to treat urinary tract infection. For MDR-KPN, a combination of multiple antibiotics is necessary.

Identification of Potential Inhibitors of Three NDM Variants of Klebsiella Species from Natural Compounds: A Molecular Docking, Molecular Dynamics Simulation and MM-PBSA Study

BACKGROUND

Klebsiella species have emerged as well-known opportunistic pathogens causing nosocomial infections with β-lactamase-mediated resistance as a prevalent antibiotic resistance mechanism. The discovery and emergence of metallo-β-lactamases, mainly new- Delhi metallo-β-lactamases (NDMs), have increased the threat and challenges in healthcare facilities.

OBJECTIVES

A computational screening was conducted using 570 natural compounds from Dr. Duke's Phytochemical and Ethnobotanical data to discover promising inhibitors for NDM-6, NDM-9, and NDM-23 of the Klebsiella species.

METHODS

Using homology modeling on the Raptor-X web server, the structures of the three NDM variants were predicted. The structures were validated using various computational tools and MD simulation for 50 ns. Lipinski - Vebers' Filter and ADMET Screening were used to screen 570 compounds, followed by docking in Biovia Discovery Studio 2019 using the CDOCKER module. GROMACS was used to simulate the compounds with the highest scores with the proteins for 50 ns. Using the MM-PBSA method and g_mmpbsa tool, binding free energies were estimated and per-residue decomposition analysis was conducted.

RESULTS

The three structures predicted were found stable after the 50 ns MD Simulation run. The compounds Budmunchiamine-A and Rhamnocitrin were found to have the best binding energy towards NDM-6, NDM-9, and NDM-23, respectively. From the results of MD Simulation, MM-PBSA binding free energy calculations, and per-residue decomposition analysis, the Protein-ligand complex of NDM-6 with Budmunchiamine A and NDM-9 with Rhamnocitrin was relatively more stable than the complex of NDM-23 and Rhamnocitrin.

CONCLUSION

The study suggests that Budmunchiamine-A and Rhamnocitrin are potential inhibitors of NDM-6 and NDM-9, respectively, and may pave a path for in-vivo and in-vitro studies in the future.

Growing Concerns on Antimicrobial Resistance - Past, Present, and Future Trends

Antimicrobial resistance [AMR] is a global problem that affects multiple domains including healthcare, agriculture, aquaculture, and many more. Every year, 700,000 people die from it. AMR is predicted to claim 10 million lives by 2050 if immediate action is not taken. Thus, to halt the spread of AMR it is important to understand what contributes to its emergence and transmission across borders and domains. The burden is disproportionately higher in Low middle income countries (LMICs) due to multiple factors such as environmental, social, healthcare, and cultural barriers. This review paper describes the comprehensive analysis of the past, present, and future trends in AMR, focusing on the complex interconnectedness of the factors contributing to this issue. Historical trends reveal antibiotic discoveries, resistance periods, resistance genes, and multidrug-resistant pathogens, providing insights into crisis evolution and the emergence of multidrug-resistant pathogens. The present trends reflect the current state of AMR in India and emphasize the negative consequences of AMR for clinical medicine and healthcare systems. It identifies the factors driving the global pandemic surge and examines current global and country-level policies and actions to mitigate its impact. The future trends anticipate the trajectories of AMR and discuss innovative approaches to combat resistance, including the exploration of alternative therapies and the implementation of stewardship programs. Thus, by synthesizing existing knowledge and identifying emerging gaps, this review paper presents a holistic perspective on the evolution of AMR.

Whole Genome Sequencing Insights on Extensive Drug Resistant Klebsiella pneumoniae and Pseudomonas aeruginosa Traumatic Infection

<b>Background and Objective:</b> It is well documented that Whole Genome Sequencing (WGS) has recently used to explore new resistance patterns and track the dissemination of extensive and pan drug-resistant microbes in healthcare settings. This article explores the link between traumatic infections caused by road traffic accidents (RTAs) leading to coma and the development of chest infections caused by extensively drug-resistant (XDR) <i>Klebsiella pneumoniae</i> and <i>Pseudomonas aeruginosa</i>. <b>Materials and Methods:</b> The study was carried out from March to December 2022 which included a 45-year-old male patient admitted to the ICU of Al Ramadi Teaching Hospitals following a severe RTA that resulted in a TBI and subsequent coma. Two study isolates were diagnosed bacteriologically using the VITEK^®-2 technique including resistant mechanisms like extended-spectrum beta-lactamases and carbapenemases. Whole genome sequencing was performed using a DNA nanoball sequencing platform from BGI-Tech. Genome assembly and annotation were done using the bacterial bioinformatics resource center. The report on Comprehensive Genome Analysis includes a phylogenetic analysis using the reference and representative genomes provided by PATRIC. <b>Results:</b> <i>Klebsiella pneumoniae</i> and <i>P. aeruginosa</i> isolates were XDR, producing ESBLs and carbapenemases. The WGS detection NDM-5 gene in the <i>K. pneumoniae</i> strain is not very common compared to the NDM-1 and blaOXA-181 g. At the same time, a file in <i>P. aeruginosa</i> isolate found genes GES-type ESBL (not reported in Iraq before), blaPAO and blaOXA-396 with NDM-1 all these genes are carbapenemases. In phylogenetic analysis, the <i>K. pneumoniae</i> isolate has an evolutionary relationship with strains originating from China while <i>P. aeruginosa</i> was globally unique. <b>Conclusion:</b> The XDR <i>K. pneumoniae</i> and <i>P. aeruginosa</i> pose a public health threat. The WGS revealed unique virulence and antibiotic-resistance genes associated with nosocomial outbreaks. The XDR isolates carrying NDM-5, blaOXA-181 and GES-type ESBL genes were detected.

Recent discoveries of propyl gallate restore the antibacterial effect of tigecycline against tet(X4)-positive Escherichia coli

Propyl gallate (PG), an approved food additive, can be added to different foods and drugs to provide health benefits with minimal danger. However, no clinical application of PG as an antibacterial agent for the treatment of antimicrobial resistance (AMR) has been documented. The aim of this study was to elucidate the effects and mechanisms by which PG inhibits the activity of Tet(X4). Enzyme activity inhibition assay, antimicrobial tests, scanning electron microscopy (SEM) assay, molecular docking and dynamics simulation assays, and animal infection models were used to confirm the synergistic efficacy and mechanism. Here, we found that PG efficiently inhibited Tet(X4) enzyme activity (IC50 = 34.83 μg/mL) while affecting the expression of tet(X4). PG has a synergistic effect with tigecycline (fractional inhibitory concentration index (FICI) < 0.5) against tet(X4)-positive Escherichia coli (E. coli) isolates of animal origin. The survival rates of G. mellonella larvae and the mouse systemic infection model increased by 60 % and 39 %, respectively. The combination of PG and tigecycline showed remarkable treatment benefits in terms of the bacterial load and inflammatory factors in mice. Our results indicate that PG is a valuable adjuvant with tetracyclines and can be considered to address the inevitable infection caused by tet(X4)-positive bacteria, which is a feasible way to extend the lifespan of existing antibiotics.

Laboratory detection of carbapenemases among Gram-negative organisms

SUMMARYThe carbapenems remain some of the most effective options available for treating patients with serious infections due to Gram-negative bacteria. Carbapenemases are enzymes that hydrolyze carbapenems and are the primary method driving carbapenem resistance globally. Detection of carbapenemases is required for patient management, the rapid implementation of infection prevention and control (IP&C) protocols, and for epidemiologic purposes. Therefore, clinical and public health microbiology laboratories must be able to detect and report carbapenemases among predominant Gram-negative organisms from both cultured isolates and direct from clinical specimens for treatment and surveillance purposes. There is not a "one size fits all" laboratory approach for the detection of bacteria with carbapenemases, and institutions need to determine what fits best with the goals of their antimicrobial stewardship and IP&C programs. Luckily, there are several options and approaches available for clinical laboratories to choose methods that best suits their individual needs. A laboratory approach to detect carbapenemases among bacterial isolates consists of two steps, namely a screening process (e.g., not susceptible to ertapenem, meropenem, and/or imipenem), followed by a confirmation test (i.e., phenotypic, genotypic or proteomic methods) for the presence of a carbapenemase. Direct from specimen testing for the most common carbapenemases generally involves detection via rapid, molecular approaches. The aim of this article is to provide brief overviews on Gram-negative bacteria carbapenem-resistant definitions, types of carbapenemases, global epidemiology, and then describe in detail the laboratory methods for the detection of carbapenemases among Gram-negative bacteria. We will specifically focus on the Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex.

Role of Ceftazidime-Avibactam in Urinary Tract Infections Caused by Carbapenem-Resistant Enterobacterales

Introduction Urinary tract infections (UTIs) are one of the most common bacterial infections encountered in community and healthcare settings. Increasing antimicrobial resistance patterns worldwide have limited the treatment options available. Overuse of carbapenems which were considered as the last resort for multi-drug resistant UTIs over the past decade has led to the emergence of carbapenem-resistant Enterobacterales (CRE). Ceftazidime-avibactam is a novel beta-lactam inhibitor combination drug indicated for the treatment of complicated UTIs caused by CRE. Materials and methods This was a prospective, observational study conducted in the Department of Microbiology at Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow from January 1, 2022, to June 30, 2022. A total of 1716 urine samples were processed for identification and antimicrobial susceptibility testing. This research was approved by the Institutional Ethics Committee (IEC) of Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, under IEC number 140/20. Isolates belonging to Enterobacterales and showing resistance to carbapenems were selected for further processing. Epidemiological details and the antimicrobial susceptibility profile of all patients with CRE uropathogens were compared. These isolates were then tested for susceptibility to ceftazidime-avibactam (30/20 μg) disc using the Kirby-Bauer disc diffusion method. A subset (n= 20) of CRE isolates were chosen for gene detection using multiplex polymerase chain reaction followed by synergy testing using ceftazidime-avibactam and aztreonam gradient strip-based susceptibility testing. Results In the 1716 samples processed, only 28.1% samples had significant growth out of which 15.3% isolates belonged to Enterobacterales and showed in-vitro resistance to imipenem/meropenem. CRE were approximately two times more common in men as compared to women in the age group of 41-60 years (31.1%). The majority were inpatient samples (72%). The antimicrobial susceptibility profile of the CRE uropathogens showed maximum susceptibility to fosfomycin (66.7%), nitrofurantoin (30.7%), and aminoglycosides (13.5%) and maximum resistance to norfloxacin (100%), cefazolin (98.7%), and netilmicin (98.7%). Ceftazidime-avibactam had an in vitro resistance of 91.9%. The most common gene detected was NDM followed by KPC. The isolates that were resistant to ceftazidime-avibactam and positive for NDM gene (n=20) on being tested for phenotypic synergy using ceftazidime-avibactam and aztreonam E strips showed 100% susceptibility. Conclusion Carbapenem-resistant gram-negative pathogens have become a major healthcare burden. They limit the treatment options available thereby increasing the morbidity and mortality in patients. Carbapenems which were at one time considered as the last line of treatment are deemed ineffective by these superbugs. CRE are among the most dreaded infectious agents. Ceftazidime-avibactam has been suggested as a therapeutic option for the management of CRE but in our study ceftazidime-avibactam alone had a high in-vitro resistance. Nonetheless, the combination of ceftazidime-avibactam and aztreonam showed good in-vitro susceptibility. Synergistic combination of these two antimicrobials can be considered as a treatment option, especially in regions where NDM is prevalent. Research is still limited regarding the clinical efficacy of this combination.

Antimicrobial resistance genes and associated mobile genetic elements in Escherichia coli from human, animal and environment

The global rise of antimicrobial resistance (AMR) poses a significant threat to human health. The environment plays an essential role in transmission of antimicrobial resistance genes (ARGs) between human and animal. Bacterial communities harbour diverse ARGs, carried by mobile genetic elements (MGEs) like plasmids and insertion sequences (ISs). Here, a total of 2199 Escherichia coli (E. coli) whole genome sequences from human, animal, bird and environment were retrieved globally to investigate ARG prevalence and assess their genetic framework. The study highlights how the genetic background including plasmids, IS elements and transposons surrounding ARGs influences their transmission potential. The maximum number of ARGs was found in United Kingdom followed by USA, majorly in human hosts. However, IS-associated ARGs were most prevalent in bird hosts. ARGs like aph(6)-ld, aph(3″)-lb, blaCTX-M, blaNDM were widespread across all hosts. Tn2 was the most prevalent, majorly carried by IncFIB plasmids. The IS26 and ISVsa3 carried diverse ARGs, primarily linked to aminoglycoside and β-lactam resistance. The combinations like mph(A)_IS6100 and blaNDM-5_IS5 showed fixed IS-ARG associations. ARGs like blaNDM, blaCTX-M variants displayed strong association with IS elements. The study highlights possible mechanism of transmission due to close proximity of AMR genes to MGEs, offering promising strategies to combat AMR by predicting and addressing future resistance determinants.

Genotypic Characterisation of Carbapenem-Resistant Enterobacteriaceae in a Tertiary Care Hospital in South India

Introduction The antimicrobial resistance of Enterobacteriaceae is variable and is influenced by both geographic location and regional antibiotic use. The overuse of antibiotics, especially in hospitalised patients, suppresses the growth and persistence of drug-resistant bacteria. This study aimed to detect the prevalence of carbapenem-resistant Enterobacteriaceae and the genes responsible for the resistance. Methods A cross-sectional study has been conducted over the course of two years, from October 2021 to September 2023. A total of 2,152 samples, including pus, blood, urine, sputum and various body fluids, were collected and subjected to study. All data were analysed and presented as frequency with percentage. Results Out of 2,152 samples, 659 (32.1%) samples showed growth. Among them, 250 (38%) were found to be Enterobacteriaceae, of which 22 (8.8%) were resistant to carbapenems. The isolates were Escherichia coli (nine, 40%) followed by Klebsiella pneumoniae (eight, 36%), Morganella morganii (two, 9%), Klebsiella oxytoca (one, 5%), Proteus vulgaris (1, 5%), and Enterobacter cloacae (1, 5%). NDM (14, 63.63%) was the most common gene detected from the isolates. Conclusion Our research leads us to the conclusion that resistance to carbapenem medication can result from either the generation of carbapenemase or from non-carbapenemase mechanisms like loss of porin channels or an increase in the efflux pump. According to our research, the primary source of carbapenem resistance is metallo-β-lactamase. Therefore, it is critical for all the laboratories to identify the mechanism and incidence of carbapenem resistance in order to support epidemiological research, infection control and antibiotic stewardship.

Repurposing cetylpyridinium chloride and domiphen bromide as phosphoethanolamine transferase inhibitor to combat colistin-resistant Enterobacterales

The emergence of plasmid-encoded colistin resistance mechanisms, MCR-1, a phosphoethanolamine transferase, rendered colistin ineffective as last resort antibiotic against severe infections caused by clinical Gram-negative bacterial pathogens. Through screening FDA-approved drug library, we identified two structurally similar compounds, namely cetylpyridinium chloride (CET) and domiphen bromide (DOM), which potentiated colistin activity in both colistin-resistant and susceptible Enterobacterales. These compounds were found to insert their long carbon chain to a hydrophobic pocket of bacterial phosphoethanolamine transferases including MCR-1, competitively blocking the binding of lipid A tail for substrate recognition and modification, resulting in the increase of bacterial sensitivity to colistin. In addition, these compounds were also found to dissipate bacterial membrane potential leading to the increase of bacterial sensitivity to colistin. Importantly, combinational use of DOM with colistin exhibited remarkable protection of test animals against infections by colistin-resistant bacteria in both mouse thigh infection and sepsis models. For mice infected by colistin-susceptible bacteria, the combinational use of DOM and colistin enable us to use lower dose of colistin to for efficient treatment. These properties render DOM excellent adjuvant candidates that help transform colistin into a highly potent antimicrobial agent for treatment of colistin-resistant Gram-negative bacterial infections and allowed us to use of a much lower dosage of colistin to reduce its toxicity against colistin-susceptible bacterial infection such as carbapenem-resistant Enterobacterales.

Non-antibiotic compounds associated with humans and the environment can promote horizontal transfer of antimicrobial resistance genes

Horizontal gene transfer plays a key role in the global dissemination of antimicrobial resistance (AMR). AMR genes are often carried on self-transmissible plasmids, which are shared amongst bacteria primarily by conjugation. Antibiotic use has been a well-established driver of the emergence and spread of AMR. However, the impact of commonly used non-antibiotic compounds and environmental pollutants on AMR spread has been largely overlooked. Recent studies found common prescription and over-the-counter drugs, artificial sweeteners, food preservatives, and environmental pollutants, can increase the conjugative transfer of AMR plasmids. The potential mechanisms by which these compounds promote plasmid transmission include increased membrane permeability, upregulation of plasmid transfer genes, formation of reactive oxygen species, and SOS response gene induction. Many questions remain around the impact of most non-antibiotic compounds on AMR plasmid conjugation in clinical isolates and the long-term impact on AMR dissemination. By elucidating the role of routinely used pharmaceuticals, food additives, and pollutants in the dissemination of AMR, action can be taken to mitigate their impact by closely monitoring use and disposal. This review will discuss recent progress on understanding the influence of non-antibiotic compounds on plasmid transmission, the mechanisms by which they promote transfer, and the level of risk they pose.

Integrative metagenomic dissection of last-resort antibiotic resistance genes and mobile genetic elements in hospital wastewaters

Hospital wastewater is a critical source of antimicrobial resistance (AMR), which facilitates the proliferation and spread of clinically significant antimicrobial resistance genes (ARGs) and pathogenic bacteria. This study utilized metagenomic approaches, including advanced binning techniques, such as MetaBAT2, MaxBin2, and CONCOCT, which offer significant improvements in accuracy and completeness over traditional binning methods. These methods were used to comprehensively assess the dynamics and composition of resistomes and mobilomes in untreated wastewater samples taken from two general hospitals and one cancer hospital. This study revealed a diverse bacterial landscape, largely consisting of Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, with notable variations in microbial composition among hospitals. Analysis of the top 15 genera showed unique microbial pattern distribution in each hospital: Aeromonas was predominant in 1stHWTS (49.39 %), Acidovorax in the CAHWTS at 16.85 %, and Escherichia and Bacteroides in the 2ndHWTS at 11.44 % and 11.33 %, respectively. A total of 114 pathogenic bacteria were identified, with drug-resistant Aeromonas caviae and Escherichia coli being the most prevalent. The study identified 34 types and 1660 subtypes of ARGs, including important last-resort antibiotic resistance genes (LARGs), such as blaNDM, mcr, and tet(X). Using metagenomic binning, this study uncovered distinct patterns of host-resistance associations, particularly with Proteobacteria and Firmicutes. Network analysis highlighted the complex interactions among ARGs, mobile genetic elements (MGEs), and bacterial species, all contributing to the dissemination of AMR. These findings emphasize the intricate nature of AMR in hospital wastewater and the influence of hospital-specific factors on microbial resistance patterns. This study provides support for implementing integrated management strategies, including robust surveillance, advanced wastewater treatment, and strict antibiotic stewardship, to control the dissemination of AMR. Understanding the interplay among bacterial communities, ARGs, and MGEs is important for developing effective public health measures against AMR.

Inosine reverses multidrug resistance in Gram-negative bacteria carrying mobilized RND-type efflux pump gene cluster tmexCD-toprJ

Antimicrobial resistance is rapidly increasing worldwide, highlighting the urgent need for pharmaceutical and nonpharmaceutical interventions to tackle different-to-treat bacterial infections. Tigecycline, a semi-synthesis glycylcycline for parenteral administration, is widely recognized as one of the few effective therapies available against pan-drug resistant Gram-negative pathogens. Regrettably, the efficacy of multiple drugs, including tigecycline, is currently being undermined due to the emergence of a recently discovered mobilized resistance-nodulation-division-type efflux pump gene cluster tmexCD1-toprJ1. Herein, by employing untargeted metabolomic approaches, we reveal that the expression of tmexCD1-toprJ1 disrupts bacterial purine metabolism, with inosine being identified as a crucial biomarker. Notably, the supplementation of inosine effectively reverses tigecycline resistance in tmexCD1-toprJ1-positive bacteria. Mechanistically, exogenous inosine enhanced bacterial proton motive force, which promotes the uptake of tigecycline. Furthermore, inosine enhances succinate biosynthesis by stimulating the tricarboxylic acid cycle. Succinate interacts with the two-component system EnvZ/OmpR and upregulates OmpK 36, thereby promoting the influx of tigecycline. These actions collectively lead to the increased intracellular accumulation of tigecycline. Overall, our study offers a distinct combinational strategy to manage infections caused by tmexCD-toprJ-positive bacteria.

IMPORTANCE

TMexCD1-TOprJ1, a mobilized resistance-nodulation-division-type efflux pump, confers phenotypic resistance to multiple classes of antibiotics. Nowadays, tmexCD-toprJ has disseminated among diverse species of clinical pathogens, exacerbating the need for novel anti-infective strategies. In this study, we report that tmexCD1-toprJ1-negative and -positive bacteria exhibit significantly different metabolic flux and characteristics, especially in purine metabolism. Intriguingly, the addition of inosine, a purine metabolite, effectively restores the antibacterial activity of tigecycline by promoting antibiotic uptake. Our findings highlight the correlation between bacterial mechanism and antibiotic resistance, and offer a distinct approach to overcome tmexCD-toprJ-mediated multidrug resistance.

Characterization of microbiome, resistome, mobilome, and virulome in anoxic and oxic wastewater treatment processes in Slovakia and Taiwan

This study presents a comprehensive analysis of samples from urban wastewater treatment plants using anoxic/oxic processes in Slovakia and Taiwan, focusing on microbiome, resistome, mobilome, and virulome, which were analyzed using a shotgun metagenomic approach. Distinct characteristics were observed; in Taiwan, a higher abundance and diversity of antibiotic resistance genes were found in both influent and effluent samples, while there was a higher prevalence of mobile genetic elements and virulence factor genes in Slovakia. Variations were noted in microbial community structures; influent samples in Taiwan were reflected from fecal and hospital sources, and those in Slovakia were derived from environmental elements. At the genus level, the samples from Taiwan's sewage treatment plants were dominated by Cloacibacterium and Bacteroides, while Acinetobacter was predominant in samples from Slovakia. Despite similar antibiotic usage patterns, distinct wastewater characteristics and operational disparities influenced microbiome, resistome, mobilome, and virulome compositions, with limited reduction of most resistance genes by the studied anoxic/oxic processes. These findings underscore the importance of region-specific insights into microbial communities for understanding the dynamics of antimicrobial resistance and pathogenicity in urban wastewater treatment systems. Such insights may lay the groundwork for optimizing treatment processes and reducing the dissemination of antibiotic resistance and pathogenicity genes for safeguarding public health.

Characterization, Antibiotic Susceptibility, and Clonal Analysis of Carbapenem-Resistant Klebsiella pneumoniae From Different Clinical Cases

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is recognized for its great ability to resist prescription drugs and its association with severe infections in humans.

OBJECTIVES

This study was designed to evaluate the characteristic resistance spectrum, to characterize the implicated carbapenem-resistant genes (CRGs), and to determine the extent of genetic diversity among Klebsiella pneumoniae isolates from human clinical cases in Duhok province.  Methodology: The VITEK-2 system was used to investigate the phenotypic antibiotic susceptibility of 23 K. pneumoniae isolated from distinct human clinical situations, multiplex PCR was used to assign the key common carbapenem-resistant genes (IMP, OXA48-like, bla-NDM, and KPC) in phenotypically carbapenem-resistant isolates, and the Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) assay was utilized to ascertain the clonal associations among those isolates.

RESULTS

Phenotypic resistance analysis revealed high resistance rates to various antibiotics, with all isolates exhibiting multidrug resistance (MDR). Coronavirus disease 2019 (COVID-19) patient isolates demonstrated significantly higher resistance compared to other sources. In addition, all isolates showed complete phenotypic resistance to carbapenems, PCR screening for CRGs identified blaOXA-48 as the predominant gene, present in all isolates. Genetic fingerprinting revealed diverse genotypes, with COVID-19 patient isolates exhibiting high similarity, contrasting with maximum diversity in non-COVID-19 clinical isolates.

Evaluation of synergism effect of human glucose-dependent insulinotropic polypeptide (GIP) on Klebsiella pneumoniae carbapenemases (KPC) producer isolated from clinical samples

Antibiotic resistance is increasing among Gram-negative bacteria, prompting the development of new antibiotics as well as alternative treatment approaches. Klebsiella pneumoniae Carbapenemases (KPC) has become a major concern in the treatment of infections, since KPC-producing bacteria are resistant to a number of β -lactam and non β-lactam antibiotics in addition to hydrolyzing carbapenemases. The aim of this study is to examine the synergistic effect of human Glucose-dependent Insulinotropic Polypeptide (GIP) on KPC producer. The K. pneumoniae isolates were identified by using biochemical tests and PCR genotyping. The disc diffusion method was used to assess the antimicrobial susceptibility of each isolate, and the modified Hodge test (MHT) was used to find carbapenemases. Agar well diffusion and minimum inhibitory concentration (MIC) assays were used to validate the synergistic effect of GIP against Klebsiella species. MIC values of chosen antimicrobial compounds demonstrated a considerable synergism impact when combined with human GIP, particularly against KPC strains. The antibacterial activity of the antimicrobial compounds was boosted by 4-16 times due to human GIP, reducing the MIC values. The fractional inhibitory concentration (FIC) ranged from 0.032 to 0.25 for examined antibiotics. Thus, GIP can be considered an antibacterial adjuvant with the potential to supplement the current antibiotic spectrum.

Simultaneous clonal spread of NDM-1-producing Pseudomonas aeruginosa ST773 from Ukrainian patients in the Netherlands and Spain

Objectives

We describe the clonal spread of New Delhi metallo-β-lactamase (NDM) 1-producing Pseudomonas aeruginosa isolates belonging to the ST773 clone in Spain and the Netherlands, associated with the transfer of Ukrainian patients during the war.

Methods

Between March and December 2022, nine NDM-1-producing P. aeruginosa ST773 isolates were recovered from nine Ukrainian patients evacuated to two Spanish (n = 3) and five Dutch (n = 6) hospitals. Antimicrobial susceptibility testing was studied (Sensititre, Microscan, EUCAST-2023). Whole genome sequencing (Illumina, Oxford-Nanopore) was used to analyze the genetic relatedness, the resistome, and the prophage content.

Results

All NDM-1-producing P. aeruginosa ST773 isolates exhibited resistance to all tested antimicrobials except colistin, aztreonam, and cefiderocol. Genomic analysis revealed that all isolates had an identical resistome and a chromosomally encoded integrative conjugative element carrying the bla NDM-1 gene. The core genome multilocus sequence typing and core genome single nucleotide polymorphisms analysis showed highly related isolates, irrespective of country of isolation, distant from other NDM-1-ST773 P. aeruginosa not collected in Ukraine. Both analysis revealed two closely related clusters, spanning the Spanish and Dutch isolates. In addition, a high content of prophages was identified in all strains, most of them in more than one isolate simultaneously, regardless of their origin country. Moreover, an identical phage tail-like bacteriocin cluster was identified in all NDM-1-ST773 P. aeruginosa.

Conclusions

We report a clonal dissemination of NDM-producing P. aeruginosa ST773 to the Netherlands and Spain associated with patients from Ukraine. Our work highlights the importance of genomic surveillance and to understand the dynamics of resistance in multidrug-resistant bacteria after the transfer of patients from conflict zones. International collaboration is crucial to address global antimicrobial resistance.

Carbapenemase producing Gram negative bacteria: Review of resistance and detection methods

Gram negative bacilli that are carbapenem resistant have emerged and are spreading worldwide. Infections caused by carbapenem resistant isolates posses a significant threat due to their high morbidity and mortality rates. Carbapenemases production by multi-drug resistant pathogens severely restricts treatment choices for illnesses caused by bacteria that are resistant to both carbapenems and majority of β-lactam antibiotics. Various phenotypic and genotypic methods for identification can distinguish between different classes of carbapenemase and identify pathogens that are resistant to carbapenems. The establishment of a quick, accurate and reliable test for identifying the clinical strains that produce the carbapenemase enzyme is essential for optimum diagnosis of microbial pathogens and management of the global rise in the prevalence of carbapenemase producing bacterial strains. The aim of this review was to summarize the mechanisms of carbapenem resistance and to provide an overview of different carbapenemase detection methods for carbapenem resistant Gram negative bacilli.

Antimicrobial peptides: Opportunities and challenges in overcoming resistance

Antibiotic resistance represents a global health threat, challenging the efficacy of traditional antimicrobial agents and necessitating innovative approaches to combat infectious diseases. Among these alternatives, antimicrobial peptides have emerged as promising candidates against resistant pathogens. Unlike traditional antibiotics with only one target, these peptides can use different mechanisms to destroy bacteria, with low toxicity to mammalian cells compared to many conventional antibiotics. Antimicrobial peptides (AMPs) have encouraging antibacterial properties and are currently employed in the clinical treatment of pathogen infection, cancer, wound healing, cosmetics, or biotechnology. This review summarizes the mechanisms of antimicrobial peptides against bacteria, discusses the mechanisms of drug resistance, the limitations and challenges of AMPs in peptide drug applications for combating drug-resistant bacterial infections, and strategies to enhance their capabilities.

High-throughput microfluidic quantitative PCR system for the simultaneous detection of antibiotic resistance genes and bacterial and viral pathogens in wastewater

Comprehensive data on bacterial and viral pathogens of diarrhea and studies applying culture-independent methods for examining antibiotic resistance in wastewater are lacking. This study aimed to simultaneously quantify antibiotic resistance genes (ARGs), class 1 integron-integrase (int1), bacterial and viral pathogens of diarrhea, 16S rRNA, and other indicators using a high-throughput quantitative PCR (HT-qPCR) system. Thirty-six grab wastewater samples from a wastewater treatment plant in Japan, collected three times a month between August 2022 and July 2023, were centrifuged, followed by nucleic acid extraction, reverse transcription, and HT-qPCR. Fourteen targets were included, and HT-qPCR was performed on the Biomark X9™ System (Standard BioTools). For all qPCR assays, R2 was ≥0.978 and the efficiencies ranged from 90.5% to 117.7%, exhibiting high performance. Of the 36 samples, 20 (56%) were positive for Norovirus genogroup II (NoV-GII), whereas Salmonella spp. and Campylobacter jejuni were detected in 24 (67%) and Campylobacter coli in 13 (36%) samples, with mean concentrations ranging from 3.2 ± 0.8 to 4.7 ± 0.3 log10 copies/L. NoV-GII detection ratios and concentrations were higher in winter and spring. None of the pathogens of diarrhea correlated with acute gastroenteritis cases, except for NoV-GII, suggesting the need for data on specific bacterial infections to validate bacterial wastewater-based epidemiology (WBE). All samples tested positive for sul1, int1, and blaCTX-M, irrespective of season. The less explored blaNDM-1 showed a wide prevalence (>83%) and consistent abundance ranging from 4.3 ± 1.0 to 4.9 ± 0.2 log10 copies/L in all seasons. sul1 was the predominant ARG, whereas absolute abundances of 16S rRNA, int1, and blaCTX-M varied seasonally. int1 was significantly correlated with blaCTX-M in autumn and spring, whereas it showed no correlation with blaNDM-1, questioning the applicability of int1 as a sole indicator of overall resistance determinants. This study exhibited that the HT-qPCR system is pivotal for WBE.

Rapid Reversal of Carbapenemase-Producing Pseudomonas aeruginosa Epidemiology from blaVIM- to blaNDM-harbouring Isolates in a Greek Tertiary Care Hospital

Carbapenemase-producing Pseudomonas aeruginosa strains present a specific geographical distribution regarding the type of carbapenemase-encoding genes that they harbor. For more than twenty years, VIM-type enzymes were the only major carbapenemases that were detected among P. aeruginosa isolates in Greece until the emergence of NDM-1-encoding P. aeruginosa in early 2023. In the present study, we present the rapid reversal of the carbapenemase-producing P. aeruginosa epidemiology from blaVIM- to blaNDM-harbouring isolates that occurred in our hospital since then. Between January 2023 and February 2024, 139 isolates tested positive for carbapenemase production with the NG-Test CARBA 5 immunochromatographic assay. Eight isolates were processed with the Hybrispot antimicrobial resistance direct flow chip molecular assay, and the first NDM-producing isolate was further analyzed through whole genome sequencing and bioinformatics analysis. Multiple resistance genes were detected by molecular techniques in accordance with the extensively drug-resistant phenotype. The isolate that was subjected to whole-genome sequencing belonged to the P. aeruginosa high-risk clone ST308, and the blaNDM was located in the chromosome in accordance with previously reported data. During the study period, NDM-producing isolates were increasingly detected, and only five months after their emergence, they overcame VIM producers. Our results indicate the potential of this new clone to spread rapidly and predominate within healthcare institutions, further restricting the already limited treatment options.

Etiological spectrum and diagnostic challenges of short-duration fever in West Bengal (India). A cross-sectional tertiary care study

INTRODUCTION

The scarcity of epidemiological data on acute febrile illnesses from South Asia impairs evidence-based clinical decision-making. Our study aimed to explore the etiological spectrum of short-duration fever in patients admitted to a tertiary care hospital in West Bengal, India.

METHODS

We conducted a cross-sectional study from May 2021 to April 2022 involving 150 adult patients presenting with a fever lasting less than two weeks at Burdwan Medical College and Hospital (West Bengal, India). We performed comprehensive clinical assessments, including microbiological, serological, and other specific investigations, to identify the causes of the fever.

RESULTS

The demographic profile predominantly included individuals aged 21-40 years, with a male-to-female ratio of 1.9:1; 60.7% of participants were from rural areas. The primary etiological agents identified were scrub typhus (25.3%), dengue (15.3%), and enteric fever (13.3%). Notably, 80% of patients presented with non-localizing symptoms, while 14.7% had respiratory symptoms. Blood cultures pinpointed Salmonella typhi and Staphylococcus aureus in a minority of cases (3.3%); malaria, primarily Plasmodium vivax, was diagnosed in 12% of the cases.

CONCLUSION

Our findings highlight the complexity of diagnosing short-duration fevers, dominated by a wide range of etiological agents, with a notable prevalence of scrub typhus. These results underscore the urgent need for enhanced diagnostic facilities, including the availability of scrub typhus testing at primary healthcare centers. We recommend empirical doxycycline therapy for suspected cases and emphasize the need for further research to develop management guidelines for acute febrile illnesses. This study also highlights the importance of raising both community and clinician awareness to prevent irrational antibiotic use.

New Delhi Metallo-Beta-Lactamase Inhibitors: A Systematic Scoping Review

Background/Objectives: Among various carbapenemases, New Delhi metallo-beta-lactamases (NDMs) are recognized as the most powerful type capable of hydrolyzing all beta-lactam antibiotics, often conferring multi-drug resistance to the microorganism. The objective of this review is to synthesize current scientific data on NDM inhibitors to facilitate the development of future therapeutics for challenging-to-treat pathogens. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews, we conducted a MEDLINE search for articles with relevant keywords from the beginning of 2009 to December 2022. We employed various generic terms to encompass all the literature ever published on potential NDM inhibitors. Results: Out of the 1760 articles identified through the database search, 91 met the eligibility criteria and were included in our analysis. The fractional inhibitory concentration index was assessed using the checkerboard assay for 47 compounds in 37 articles, which included 8 compounds already approved by the Food and Drug Administration (FDA) of the United States. Time-killing curve assays (14 studies, 25%), kinetic assays (15 studies, 40.5%), molecular investigations (25 studies, 67.6%), in vivo studies (14 studies, 37.8%), and toxicity assays (13 studies, 35.1%) were also conducted to strengthen the laboratory-level evidence of the potential inhibitors. None of them appeared to have been applied to human infections. Conclusions: Ongoing research efforts have identified several potential NDM inhibitors; however, there are currently no clinically applicable drugs. To address this, we must foster interdisciplinary and multifaceted collaborations by broadening our own horizons.

Vermicompost: In situ retardant of antibiotic resistome accumulation in cropland soils

The dissemination of antibiotic resistance genes (ARGs) in soil has become a global environmental issue. Vermicomposting is gaining prominence in agricultural practices as a soil amendment to improve soil quality. However, its impact on soil ARGs remains unclear when it occurs in farmland. We comprehensively explored the evolution and fate of ARGs and their hosts in the field soil profiles under vermicompost application for more than 3 years. Vermicompost application increased several ARG loads in soil environment but decreased the high-risk bla-ARGs (blaampC, blaNDM, and blaGES-1) by log(0.04 - 0.43). ARGs in soil amended with vermicompost primarily occurred in topsoil (approximately 1.04-fold of unfertilized soil), but it is worth noting that their levels in the 40-60 cm soil layer were the same or even less than in the unfertilized soil. The microbial community structure changed in soil profiles after vermicompost application. Vermicompost application altered the microbial community structure in soil profiles, showing that the dominant bacteria (i.e., Proteobacteria, Actinobacteriota, Firmicutes) were decreased 2.62%-5.48% with the increase of soil depth. A network analysis further revealed that most of ARG dominant host bacteria did not migrate from surface soil to deep soil. In particular, those host bacteria harboring high-risk bla-ARGs were primarily concentrated in the surface soil. This study highlights a lower risk of the propagation of ARGs caused by vermicompost application and provides a novel approach to reduce and relieve the dissemination of ARGs derived from animals in agricultural production.

Microcin C7 as a Potential Antibacterial-Immunomodulatory Agent in the Postantibiotic Era: Overview of Its Bioactivity Aspects and Applications

In the postantibiotic era, the pathogenicity and resistance of pathogens have increased, leading to an increase in intestinal inflammatory disease. Bacterial infections remain the leading cause of animal mortality. With increasing resistance to antibiotics, there has been a significant decrease in resistance to both inflammation and disease in animals, thus decreasing production efficiency and increasing production costs. These side effects have serious consequences and have detracted from the development of China's pig industry. Microcin C7 (McC7) demonstrates potent antibacterial activity against a broad spectrum of pathogens, stable physicochemical properties, and low toxicity, reducing the likelihood of resistance development. Thus, McC7 has received increasing attention as a potential clinical antibacterial and immunomodulatory agent. McC7 has the potential to serve as a new generation of antibiotic substitutes; however, its commercial applications in the livestock and poultry industry have been limited. In this review, we summarize and discuss the biosynthesis, biochemical properties, structural characteristics, mechanism of action, and immune strategies of McC7. We also describe the ability of McC7 to improve intestinal health. Our aim in this study was to provide a theoretical basis for the application of McC7 as a new feed additive or new veterinary drug in the livestock and poultry breeding industry, thus providing a new strategy for alleviating resistance through feed and mitigating drug resistance. Furthermore, this review provides insight into the new functions and anti-infection mechanisms of bacteriocin peptides and proposes crucial ideas for the research, product development, and application of bacteriocin peptides in different fields, such as the food and medical industries.

VirBR, a transcription regulator, promotes IncX3 plasmid transmission, and persistence of blaNDM-5 in zoonotic bacteria

IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, blaNDM-5, are rapidly spreading globally in both humans and animals. Given that carbapenems are listed on the WHO AWaRe watch group and are prohibited for use in animals, the drivers for the successful dissemination of Carbapenem-Resistant Enterobacterales (CRE) carrying blaNDM-5-IncX3 plasmids still remain unknown. We observe that E. coli carrying blaNDM-5-IncX3 can persist in chicken intestines either under the administration of amoxicillin, one of the largest veterinary β-lactams used in livestock, or without any antibiotic pressure. We therefore characterise the blaNDM-5-IncX3 plasmid and identify a transcription regulator, VirBR, that binds to the promoter of the regulator gene actX enhancing the transcription of Type IV secretion systems (T4SS); thereby, promoting conjugation of IncX3 plasmids, increasing pili adhesion capacity and enhancing the colonisation of blaNDM-5-IncX3 transconjugants in animal digestive tracts. Our mechanistic and in-vivo studies identify VirBR as a major factor in the successful spread of blaNDM-5-IncX3 across one-health AMR sectors. Furthermore, VirBR enhances the plasmid conjugation and T4SS expression by the presence of copper and zinc ions, thereby having profound ramifications on the use of universal animal feeds.

The scope of the antimicrobial resistance challenge

Each year, an estimated 7·7 million deaths are attributed to bacterial infections, of which 4.95 million are associated with drug-resistant pathogens, and 1·27 million are caused by bacterial pathogens resistant to the antibiotics available. Access to effective antibiotics when indicated prolongs life, reduces disability, reduces health-care expenses, and enables access to other life-saving medical innovations. Antimicrobial resistance undoes these benefits and is a major barrier to attainment of the Sustainable Development Goals, including targets for newborn survival, progress on healthy ageing, and alleviation of poverty. Adverse consequences from antimicrobial resistance are seen across the human life course in both health-care-associated and community-associated infections, as well as in animals and the food chain. The small set of effective antibiotics has narrowed, especially in resource-poor settings, and people who are very young, very old, and severely ill are particularly susceptible to resistant infections. This paper, the first in a Series on the challenge of antimicrobial resistance, considers the global scope of the problem and how it should be measured. Robust and actionable data are needed to drive changes and inform effective interventions to contain resistance. Surveillance must cover all geographical regions, minimise biases towards hospital-derived data, and include non-human niches.

Binding selectivity analysis of new delhi metallo-beta-lactamase-1 inhibitors using molecular dynamics simulations: Exploring possibilities for decoding antimicrobial drug resistance

BACKGROUND

New Delhi metallo-beta-lactamase-1 (NDM1) confers resistance to several bacterial species against a broad range of beta-lactam antibiotics and turning them into superbugs that pose a significant threat to healthcare systems worldwide. As such, it is a potentially relevant biological target for counteracting bacterial infections. Given the lack of effective treatment options against NDM1 producing bacteria, finding a reliable inhibitor for the NDM1 enzyme is crucial.

METHODS

Using molecular dynamics simulations, the binding selectivities and affinities of three ligands, viz. PNK, 3S0, and N1G were investigated against NDM1.

RESULTS

The results indicate that N1G binds with more affinity to NDM1 than PNK and 3S0. The binding energy decomposition analysis revealed that residues I35, W93, H189, K211, and N220 showed significant binding energies with PNK, 3S0, and N1G, and hence are crucially involved in the binding of the ligands to NDM1. Molecular dynamics trajectory analysis further elicited that the ligands influence dynamic flexibility of NDM1 morphology, which contributes to the partial selectivities of PNK, 3S0, and N1G.

CONCLUSIONS

This in silico study offers a vital information for developing potential NDM1 inhibitors with high selectivity. Nevertheless, in vitro and in vivo experimental validation is mandated to extend the possible applications of these ligands as NDM1 inhibitors that succor in combating antimicrobial resistance.