Emergence of carbapenem-resistant Klebsiella pneumoniae species complex from agrifood systems: detection of ST6326 co-producing KPC-2 and NDM-1.

BACKGROUND: Klebsiella pneumoniae species complex (KpSC) is an important disseminator of carbapenemase-encoding genes, mainly blaKPC-2 and blaNDM-1, from hospitals to the environment. Consequently, carbapenem-resistant strains can be spread through the agrifood system, raising concerns about food safety. This study therefore aimed to isolate carbapenem-resistant KpSC strains from the agricultural and environmental sectors and characterize them using phenotypic, molecular, and genomic analyses. RESULTS: Klebsiella pneumoniae and Klebsiella quasipneumoniae strains isolated from soils used for lemon, guava, and fig cultivation, and from surface waters, displayed an extensive drug-resistance profile and carried blaKPC-2, blaNDM-1, or both. In addition to carbapenemase-encoding genes, KpSC strains harbor a broad resistome (antimicrobial resistance and metal tolerance) and present putative hypervirulence. Soil-derived K. pneumoniae strains were assigned as high-risk clones (ST11 and ST307) and harbored the blaKPC-2 gene associated with Tn4401b and Tn3-like elements on IncN-pST15 and IncX5 plasmids. In surface waters, the coexistence of blaKPC-2 and blaNDM-1 genes was identified in K. pneumoniae ST6326, a new carbapenem-resistant regional Brazilian clone. In this case, blaKPC-2 with Tn4401a isoform and blaNDM-1 associated with a Tn125-like transposon were located on different plasmids. Klebsiella quasipneumoniae ST526 also presented the blaNDM-1 gene associated with a Tn3000 transposon on an IncX3 plasmid. CONCLUSION: These findings provide a warning regarding the transmission of carbapenemase-positive KpSC across the agricultural and environmental sectors, raising critical food safety and environmental issues. © 2024 Society of Chemical Industry.

Genomic features of an extensively drug-resistant and NDM-1-positive Klebsiella pneumoniae ST340 isolated from river water.

The environmental contamination plays a significant role in the emergence of antimicrobial resistance. In this study, we report a genomic analysis of an extensively drug-resistant and blaNDM-1-producing Klebsiella pneumoniae (EW807) strain recovered from a surface water sample. Strain EW807 belonged to sequence type (ST) 340 and serotype O4:KL15, a high-risk clone of the clonal group 258. This strain carried a broad resistome, including blaNDM-1 and blaCTX-M-15. The core genome multilocus sequence typing phylogenetic analysis revealed that the EW807 strain was most related to strains from Brazil and the USA. An IncX3 plasmid was identified harboring the blaNDM-1 gene, while an IncFIB(K) plasmid was detected carrying the blaCTX-M-15 in addition to multidrug resistance and multimetal tolerance regions. IncX3 and IncFIB(K) plasmids shared high similarity with plasmids from a human in China and a dog in Brazil, respectively. The regions harboring the blaNDM-1 and blaCTX-M-15 genes contained sequences from the Tn3 family. These findings suggest that IncX3 plasmid could play a role in the spread of NDM-1 in a post-pandemic scenario. To the best of our knowledge, this is the first report of blaNDM-1-producing K. pneumoniae ST340 O4:KL15 strain in the environment. Therefore, the presence of high-risk clones of K. pneumoniae carrying carbapenemases in the environment requires strict surveillance.

Multidrug-resistant Shiga toxin-producing Escherichia coli and hybrid pathogenic strains of bovine origin.

Antimicrobial-resistant Escherichia coli strains have been circulating in various sectors and can be cross-transferred between them. Among pathogenic E. coli strains, Shiga toxin-producing E. coli (STEC) and hybrid pathogenic E. coli (HyPEC) emerged as responsible for outbreaks worldwide. As bovine are reservoir of STEC strains, these pathogens primarily spread to food products, exposing humans to risk. Therefore, this study aimed to characterize antimicrobial-resistant and potentially pathogenic E. coli strains from fecal samples of dairy cattle. In this regard, most E. coli strains (phylogenetic groups A, B1, B2, and E) were resistant to ß-lactams and non-ß-lactams and were classified as multidrug-resistant (MDR). Antimicrobial resistance genes (ARGs) related to multidrug resistance profiles were detected. Furthermore, mutations in fluoroquinolone and colistin resistance determinants were also identified, highlighting the deleterious mutation His152Gln in PmrB that may have contributed to the high level (> 64 mg/L) of colistin resistance. Virulence genes of diarrheagenic and extraintestinal pathogenic E. coli (ExPEC) pathotypes were shared among strains and even within the same strain, evidencing the presence of HyPEC (i.e., ExPEC/STEC), which were assigned as unusual B2-ST126-H3 and B1-ST3695-H31. These findings provide phenotypic and molecular data of MDR, ARGs-producing, and potentially pathogenic E. coli strains in dairy cattle, contributing to the monitoring of antimicrobial resistance and pathogens in healthy animals and alerting to potential bovine-associated zoonotic infections.

Genetic plurality of blaKPC-2-harboring plasmids in high-risk clones of Klebsiella pneumoniae of environmental origin.

International high-risk clones of Klebsiella pneumoniae are important human pathogens that are spreading to the environment. In the COVID-19 pandemic scenario, the frequency of carbapenemase-producing strains increased, which can contribute to the contamination of the environment, impacting the surrounding and associated ecosystems. In this regard, KPC-producing strains were recovered from aquatic ecosystems located in commercial, industrial, or agricultural areas and were submitted to whole-genome characterization. K. pneumoniae and Klebsiella quasipneumoniae subsp. quasipneumoniae strains were assigned to high-risk clones (ST11, ST340, ST307) and the new ST6325. Virulome analysis showed genes related to putative hypervirulence. Strains were resistant to almost all antimicrobials tested, being classified as extensively drug-resistant or multidrug-resistant. In this context, a broad resistome (clinically important antimicrobials and hazardous metal) was detected. Single replicon (IncX5, IncN-pST15, IncU) and multireplicon [IncFII(K1)/IncFIB(pQil), IncFIA(HI1)/IncR] plasmids were identified carrying the blaKPC-2 gene with Tn4401 and non-Tn4401 elements. An unusual association of blaKPC-2 and qnrVC1 and the coexistence of blaKPC-2 and mer operon (mercury tolerance) was found. Comparative analysis revealed that blaKPC-2-bearing plasmids were most similar to plasmids from Enterobacterales of Brazil, China, and the United States, evidencing the long persistence of plasmids at the human-animal-environmental interface. Furthermore, the presence of uncommon plasmids, displaying the interspecies, intraspecies, and clonal transmission, was highlighted. These findings alert for the spread of high-risk clones producing blaKPC-2 in the environmental sector and call attention to rapid dispersion in a post-pandemic world.

Colistin-resistant mcr-1-positive Escherichia coli ST1775-H137 co-harboring blaCTX-M-2 and blaCMY-2 recovered from an urban stream.

The rapid dissemination of colistin resistance mcr-type genes and extended-spectrum ß-lactamase-encoding genes at the human-animal-environment interface has raised concerns worldwide. In this study, we performed a genomic investigation of a multidrug (MDR)- and colistin-resistant Escherichia coli strain recovered from an urban stream strongly affected by pollution and used for recreational purposes in Brazil. E. coli strain EW827 was resistant to clinically significant antimicrobials, including polymyxins, extended-spectrum cephalosporins, and fluoroquinolones. Whole-genome sequencing analysis revealed that EW827 strain belonged to ST1775 and carried the fimH137 allele, clinically relevant antimicrobial resistance genes (e.g., mcr-1.1, blaCTX-M-2, and blaCMY-2), tolerance genes to metals, and biocide resistance genes. Moreover, IncX4 and IncI1-ST12 replicon types were identified carrying mcr-1.1 and blaCMY-2, respectively. A novel genetic environment of the mcr-1.1 gene, in which a 258-bp ∆IS5-like was inserted in the opposite orientation upstream of the mcr-1.1-pap2 element, was also detected. Additionally, the blaCTX-M-2 gene was harbored by a Tn21-like element on the chromosome. The occurrence of MDR E. coli co-harboring mcr-1.1, blaCTX-M-2, and blaCMY-2 in urban water represents a potential risk to humans, animals, and environmental safety. Therefore, epidemiological studies are required to monitoring multidrug-resistant bacteria and their antimicrobial resistance genes in aquatic ecosystems to determine possible routes and fates of these genes.