Whole-Genome Analysis of a High-Risk Clone of Klebsiella pneumoniae ST147 Carrying Both mcr-1 and blaNDM-1 Genes in Peru

Inosine monophosphate overcomes the coexisting resistance of mcr-1 and blaNDM-1 in Escherichia coli

INTRODUCTION

The rise of antibiotic-resistant bacteria, particularly those harboring mcr-1 and blaNDM-1, threatens public health by reducing the efficacy of colistin and carbapenems. Recently, the co-spread of mcr-1 and blaNDM-1 has been reported, and the emergence of dual-resistant Enterobacteriaceae severely exacerbates antimicrobial resistance.

OBJECTIVES

This study aims to investigate the impact of mcr-1 and blaNDM-1 expression on metabolism in Escherichia coli and to identify potential antimicrobial agents capable of overcoming the resistance conferred by these genes.

METHODS

We employed non-targeted metabolomics to profile the metabolic perturbations of E. coli strains harboring mcr-1 and blaNDM-1. The bactericidal effects of the differential metabolite, inosine monophosphate (IMP), were assessed both in vitro using time-killing assays and in vivo using a mouse infection model. The antimicrobial mechanism of IMP was elucidated through transcriptomic analysis and biochemical approaches.

RESULTS

Metabolic profiling revealed significant alterations in the purine pathway, with IMP demonstrating potent bactericidal activity against E. coli strains carrying both resistance genes. IMP increased membrane permeability, disrupted proton motive force, reduced ATP levels, induced oxidative damage by promoting reactive oxygen species and inhibiting bacterial antioxidant defenses, and improved the survival rate of infected mice.

CONCLUSION

Our findings suggest that IMP could be a promising candidate for combating mcr-1 and blaNDM-1-mediated resistance and provide a novel approach for discovering antimicrobial agents against colistin- and carbapenem-resistant bacteria.

Emerging carbapenem-resistant Klebsiella pneumoniae in a tertiary care hospital in Lima, Peru

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant public health threat, particularly in low- and middle-income countries (LMICs) with limited surveillance and treatment options. This study examines the genetic diversity, resistance patterns, and transmission dynamics of 66 CRKP isolates recovered over 5 years (2015-2019) after the first case of CRKP was identified at a tertiary care hospital in Lima, Peru. Our findings reveal a shift from blaKPC-2 to blaNDM-1 as the dominant carbapenemase gene after 2017. Lineage ST45 was the most prevalent and persisted for multiple years, followed by high-risk clones ST11 and ST147. The blaNDM-1 gene was carried almost exclusively by a Tn125-like transposon, similar to the one reported in previous studies from two Peruvian hospitals. Long-read sequencing revealed nearly identical blaNDM-carrying plasmids across the four assessed lineages. A comparative analysis of 1,023 South American CRKP genomes confirmed a unique pattern in Peru, where blaNDM-1 (81.4%) outpaced blaKPC-2, which remained dominant (59.4%) elsewhere. In addition, emerging clones ST45 and ST348 found in Peru were rarely found elsewhere in South America, suggesting potential regional adaptation. In conclusion, our study provides a comprehensive picture of the intra-hospital dynamics of these emerging pathogens and provides a framework for studying their genomic diversity in the understudied South American region.IMPORTANCEThis study provides novel insights into the transmission and genetic diversity of carbapenem-resistant Klebsiella pneumoniae, a bacteria responsible for severe infections, with limited treatment options. By examining isolates recovered over 5 years at a major hospital in Lima, Peru, we demonstrated a shift from one type of resistance gene, blaKPC, to another, blaNDM, which is more challenging to treat. Our findings reveal that specific bacterial lineages carrying the blaNDM gene in a specific plasmid are emerging in Peru, including well-known high-risk strains and others rarely found elsewhere in South America. This pattern highlights an urgent need for targeted surveillance and infection control as these strains pose a significant challenge to healthcare systems. Our study provides crucial data on Klebsiella pneumoniae in Peru, contributing to broader efforts to monitor and control antibiotic-resistant infections in South America and globally.

Molecular characterization of carbapenemase-producing Enterobacterales in a tertiary hospital in Lima, Peru

Carbapenemase-producing Enterobacterales (CPE) are a growing threat to global health and the economy. Understanding the interactions between resistance and virulence mechanisms of CPE is crucial for managing difficult-to-treat infections and informing outbreak prevention and control programs. Here, we report the characterization of 21 consecutive, unique clinical isolates of CPE collected in 2018 at a tertiary hospital in Lima, Peru. Isolates were characterized by phenotypic antimicrobial susceptibility testing and whole-genome sequencing to identify resistance determinants and virulence factors. Seven Klebsiella pneumoniae isolates were classified as extensively drug-resistant. The remaining Klebsiella, Enterobacter hormaechei, and Escherichia coli isolates were multidrug-resistant. Eighteen strains carried the metallo-β-lactamase NDM-1, two the serine-carbapenemase KPC-2, and one isolate had both carbapenemases. The blaNDM-1 gene was located in the truncated ΔISAba125 element, and the blaKPC-2 gene was in the Tn4401a transposon. ST147 was the most frequent sequence type among K. pneumoniae isolates. Our findings highlight the urgent need to address the emergence of CPE and strengthen control measures and antibiotic stewardship programs in low- and middle-income settings.IMPORTANCEGenomic surveillance of antimicrobial resistance contributes to monitoring the spread of resistance and informs treatment and prevention strategies. We characterized 21 carbapenemase-producing Enterobacterales collected at a Peruvian tertiary hospital in 2018, which exhibited very high levels of resistance and carried numerous resistance genes. We detected the coexistence of carbapenemase-encoding genes (blaNDM-1 and blaKPC-2) in a Klebsiella pneumoniae isolate that also had the PmrB(R256G) mutation associated with colistin resistance. The blaKPC-2 genes were located in Tn4401a transposons, while the blaNDM-1 genes were in the genetic structure Tn125 (ΔISAba125). The presence of high-risk clones among Klebsiella pneumoniae (ST11 and ST147) and Escherichia coli (ST410) isolates is also reported. The study reveals the emergence of highly resistant bacteria in a Peruvian hospital, which could compromise the effectiveness of current treatments and control.

Situation Report on mcr-Carrying Colistin-Resistant Clones of Enterobacterales: A Global Update Through Human-Animal-Environment Interfaces

In the twenty-first century, antibiotic resistance (ABR) is one of the acute medical emergencies around the globe, overwhelming human-animal-environmental interfaces. Hit-or-mis use of antibiotics exacerbates the crisis of ABR, dispersing transferable resistance traits and challenging treatment regimens based on life-saving drugs such as colistin. Colistin is the highest priority critically important antimicrobials for human medicine, but its long use as a growth promoter in animal husbandry reduces clinical efficacy. Since 2015, the emergence and spread of mobile colistin resistance (mcr)-carrying colistin-resistant clones of Enterobacterales have been markedly sustained in both humans and animals, especially in developing countries. Hospital and community transmissions of mcr clones pose a high risk for infection prevention and outbreaks at the national and international levels. Several public health and limited one health studies have highlighted the genomic insights of mcr clones, clarifying the chromosomal sequence types (STs) and plasmid incompatibility (Inc) types. But this information is segregated into humans and animals, and rarely are environmental sectors complicating the understanding of possibly intercontinental and sectoral transmission of these clones. India is the hotspot for superbugs, including mcr-carrying colistin-resistant isolates that threaten cross-border transmission. The current review provided an up-to-date worldwide scenario of mcr-carrying STs and plasmid Inc types among the Gram-negative bacilli of Enterobacterales across human-animal-environmental interfaces and correlated with the available information from India.

Emergence of a clinical isolate of E. coil ST297 co-carrying blaNDM-13 and mcr-1.1 in China

BACKGROUND

The coexistence of carbapenem resistance genes and mcr-1.1 in Enterobacterales has been an urgent and persistent threat to global public health. In this study, we isolated a clinical NB4833, an Escherichia coli isolate that co-carries mcr-1.1 and blaNDM-13.

OBJECTIVES

This study aimed to isolate a clinical NB4833, an Escherichia coli isolate that co-carries mcr-1.1 and blaNDM-13 and investigated the phenotypic and genotypic characteristics of plasmids harbored by E. coli isolate NB4833.

METHODS

Antimicrobial susceptibility testing and conjugation assay were performed on E. coli isolate NB4833. Stability of the plasmid and growth rate determination were used to characterize the plasmids harboring mcr-1.1 and blaNDM-13. In addition, the genetic characteristics of the plasmids were analyzed based on whole-genome sequencing of the strain and comparative genetic analysis with related plasmids.

RESULTS

Whole-genome sequencing showed that the isolate carried multiple resistance genes and possessed phenotypes indicative of all antibiotic resistance except tigecycline. And the mcr-1.1- and blaNDM-13-harbouring plasmids showed relatively high similarity to the related plasmids. The pNB4833-NDM-13 plasmid was capable of trans conjugation with an efficiency of 1.04 × 10-2 in a filter mating experiment and the transconjugant J53/ pNB4833-NDM-13 was able to be stably inherited after 10 days of passage.

CONCLUSIONS

To our knowledge, this is the first report of the coexistence of the IncI2 plasmid carrying mcr-1.1 and a blaNDM-13-carrying integrated IncFIB/IncFII plasmid in an ST297 clinical E. coli isolate. In addition, we investigated a novel plasmid carrying blaNDM-13. Our study expands the diversity of plasmids carrying blaNDM-13, which exhibits epidemic importance in bacterial resistance. Therefore, there are important measures that should be taken to prevent the spread of these plasmids.

Various arrangements of mobile genetic elements among CC147 subpopulations of Klebsiella pneumoniae harboring blaNDM-1: a comparative genomic analysis of carbapenem resistant strains

BACKGROUND

Certain clonal complexes (CCs) of Klebsiella pneumoniae such as CC147 (ST147 and ST392) are major drivers of blaNDM dissemination across the world. ST147 has repeatedly reported from our geographical region, but its population dynamics and evolutionary trajectories need to be further studied.

METHODS

Comparative genomic analysis of 51 carbapenem-nonsusceptible strains as well as three hypervirulent K. pneumoniae (hvKp) recovered during 16-months of surveillance was performed using various bioinformatics tools. We investigated the genetic proximity of our ST147 strains with publicly available corresponding genomes deposited globally and from neighbor countries in our geographic region.

RESULTS

While IncL/M plasmid harboring blaOXA-48 was distributed among divergent clones, blaNDM-1 was circulated by twenty of the 25 CC147 dominant clone and were mostly recovered from the ICU. The NDM-1 core structure was bracketed by a single isoform of mobile genetic elements (MGEs) [ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403] and was located on Col440I plasmid in 68.7% of ST392. However, various arrangements of MGEs including MITESen1/MITESen1 composite transposon or combination of MITESen1/ISSen4/IS903B/IS5/ISEhe3 on IncFIb (pB171) were identified in ST147. It seems that ST392 circulated blaNDM-1 in 2018 before being gradually replaced by ST147 from the middle to the end of sample collection in 2019. ST147 strains possessed the highest number of resistance markers and showed high genetic similarity with four public genomes that harbored blaNDM-1 on the same replicon type. Mainly, there was a convergence between clusters and isolated neighboring countries in the minimum-spanning tree. A conserved arrangement of resistance markers/MGEs was linked to methyltransferase armA which was embedded in class 1 integron in 8 isolates of ST147/ST48 high-risk clones.

CONCLUSION

Our findings highlight the dynamic nature of blaNDM-1 transmission among K. pneumoniae in Iran that occurs both clonally and horizontally via various combinations of MGEs. This is the first analysis of Iranian ST147/NDM + clone in the global context.

Genomic analysis of multidrug-resistant Escherichia coli strains carrying the mcr-1 gene recovered from pigs in Lima-Peru

Antibiotic resistance is a current problem that significantly impacts overall health. The dissemination of antibiotic resistance genes (ARGs) to urban areas primarily occurs through ARG-carrying bacteria present in the gut microbiota of animals raised in intensive farming settings, such as pig production. Hence, this study aimed to isolate and analyzed 87 Escherichia coli strains from pig fecal samples obtained from intensive farms in Lima Department. The isolates were subjected to Kirby-Bauer-Disk Diffusion Test and PCR for mcr-1 gene identification. Disk-diffusion assay revealed a high level of resistance among these isolates to oxytetracycline, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, and doxycycline. PCR analysis identified the mcr-1 gene in 8% (7/87) E. coli isolates. Further, whole genome sequencing was conducted on 17 isolates, including multidrug resistance (MDR) E. coli and/or mcr-1 gene carriers. This analysis unveiled a diverse array of ARGs. Alongside the mcr-1 gene, the bla_CTX-M55 gene was particularly noteworthy as it confers resistance to third generation cephalosporins, including ceftriaxone. MDR E. coli genomes exhibited other ARGs encoding resistance to fosfomycin (fosA3), quinolones (qnrB19, qnrS1, qnrE1), tetracyclines (tetA, tetB, tetD, tetM), sulfonamides (sul1, sul2, sul3), amphenicols (cmlA1, floR), lincosamides (inuE), as well as various aminoglycoside resistance genes. Additionally, Multi Locus Sequence Typing (MLST) revealed a high diversity of E. coli strains, including ST10, a pandemic clone. This information provides evidence of the dissemination of highly significant ARGs in public health. Therefore, it is imperative to implement measures aimed at mitigating and preventing the transmission of MDR bacteria carrying ARGs to urban environments.

Diversity of genetic platforms harboring the blaPER-2 gene in Enterobacterales and insights into the role of ISPa12 in its mobilization and dissemination

The production of PER-like extended-spectrum β-lactamases has recently been associated with reduced susceptibility to the last resort drugs aztreonam/avibactam and cefiderocol. PER-2 have been mainly confined to Argentina and neighboring countries. Until now, only three plasmids harboring bla_PER-2 genes have been characterized but very little is known about the involvement of different plasmid groups in its dissemination. This study analyzed the diversity of genetic platforms associated with bla_PER-2 genes from a collection of PER-producing Enterobacterales by describing both the close environment as well as the plasmid backbones. Full sequences of eleven plasmids were obtained by short (Illumina) and long read (Oxford Nanopore or PacBio) sequencing technologies. De novo assemblies, annotation and sequence analysis were performed by Unicycler, Prokka and BLAST. Plasmids analysis revealed that bla_PER-2 gene is encoded on plasmids of different incompatibility groups (A, C, FIB, HI1B, N2) suggesting that this gene may have been disseminated through a variety of plasmids. Analysis and comparison with the few public available nucleotide sequences describing bla_PER-2 genetic environment, including those from the environmental species Pararheinheimera spp. (considered as the progenitor of bla_PER genes), suggests a role of ISPa12 in bla_PER-2 gene mobilization from the chromosome of Pararheinheimera spp. Also, the bla_PER-2 gene was carried by a novel ISPa12-composite transposon Tn7390. In addition, its association with ISKox2-like elements in the close genetic environment in all analyzed plasmids suggests a role of this IS in further dissemination of bla_PER-2 genes.

Occurrence and Genomic Characterization of mcr-1-Harboring Escherichia coli Isolates from Chicken and Pig Farms in Lima, Peru

Resistance to colistin generated by the mcr-1 gene in Enterobacteriaceae is of great concern due to its efficient worldwide spread. Despite the fact that the Lima region has a third of the Peruvian population and more than half of the national pig and poultry production, there are no reports of the occurrence of the mcr-1 gene in Escherichia coli isolated from livestock. In the present work, we studied the occurrence of E. coli carrying the mcr-1 gene in chicken and pig farms in Lima between 2019 and 2020 and described the genomic context of the mcr-1 gene. We collected fecal samples from 15 farms in 4 provinces of Lima including the capital Lima Metropolitana and recovered 341 E. coli isolates. We found that 21.3% (42/197) and 12.5% (18/144) of the chicken and pig strains were mcr-1-positive by PCR, respectively. The whole genome sequencing of 14 mcr-1-positive isolates revealed diverse sequence types (e.g., ST48 and ST602) and the presence of other 38 genes that confer resistance to 10 different classes of antibiotics, including beta-lactamase bla_CTX-M-55. The mcr-1 gene was located on diverse plasmids belonging to the IncI2 and IncHI1A:IncHI1B replicon types. A comparative analysis of the plasmids showed that they contained the mcr-1 gene within varied structures (mikB-mcr1-pap2, ISApl1-mcr1-pap2, and Tn6330). To the best of our knowledge, this is the first attempt to study the prevalence of the mcr-1 gene in livestock in Peru, revealing its high occurrence in pig and chicken farms. The genetic diversity of mcr-1-positive strains suggests a complex local epidemiology calling for a coordinated surveillance under the One-Health approach that includes animals, retail meat, farmers, hospitals and the environment to effectively detect and limit the spread of colistin-resistant bacteria.

Emergence of coexistence of a novel blaNDM-5-harbouring IncI1-I plasmid and an mcr-1.1-harbouring IncHI2 plasmid in a clinical Escherichia coli isolate in China

BACKGROUND

Co-harbouring of carbapenem and colistin resistance genes in multidrug-resistant Enterobacterales strains poses a serious public health problem. In this study, an MCR-1.1 and NDM-5 coproducing Escherichia coli strain named EC6563 was isolated and characterized.

OBJECTIVES

This study aimed to characterize a clinical carbapenem-resistant E. coli isolate which co-harbours mcr-1.1 and bla_NDM-5 on separate plasmids, and explored the phenotypic and genotypic characteristics of the mcr-1.1- and bla_NDM-5-harbouring plasmids.

METHODS

E. coli isolate EC6563 was subjected to antimicrobial susceptibility testing, conjugation assay, stability of the plasmid and growth rate determination. In addition, the whole genome sequence of this strain was obtained and the genetic characteristics of the mcr-1.1- and bla_NDM-5-harbouring plasmids were analyzed.

RESULTS

Carbapenem-resistant E. coli isolate EC6563 was resistant to all the tested antibiotics except tigecycline. Bioinformatic analysis confirmed that the IncHI2 plasmid carrying mcr-1.1 was highly similar to the previously reported mcr-1.1-harbouring plasmid pGDP37-4, and carried multiple drug resistance genes and the IncI1-I plasmid carrying bla_NDM-5 had low similarity to the published bla_NDM-5-carrying IncI1-I plasmid pEC-16-10-NDM-5. The pEC6563-NDM5 plasmid was capable of conjugation with an efficiency of 1.34 × 10^-2 in a filter mating experiment. The transconjugant J53/pEC6563-NDM5 was able to be stably inherited after 12 days of passage.

CONCLUSIONS

To the best of our knowledge, this is the first time that an IncHI2 plasmid carrying mcr-1.1 and an IncI1-I plasmid carrying bla_NDM-5 is found to coexist in an E. coli isolate. Our research expands the known diversity of plasmids in NDM-5-producing Enterobacterales strains. Meanwhile, effective measures should be taken to prevent the spread of these plasmids.