First Report of OXA-181-Producing Enterobacterales Isolates in Latin America

Co-existence of two blaNDM-5 and blaOXA-181 on distinct plasmids in a carbapenem-resistant Klebsiella pneumoniae from a tertiary hospital, Tanzania

PURPOSE

To understand the mechanisms of carbapenem-resistant Klebsiella pneumoniae (CRKP) from Tanzania and characterize the genomes carrying the carbapenemase genes.

METHODS

Clinical CRKP isolates were selected from ongoing antimicrobial resistance surveillance at Muhimbili National Hospital, Dar es Salaam, Tanzania. Whole-genome sequencing was performed utilizing Illumina and Nanopore platforms.

RESULTS

A total of twelve CRKP were analyzed in this study. Six different multilocus sequence types were detected, six isolates were sequence type ST437 and one belonged to a novel sequence type, ST6258. Resistance to carbapenems was multifactorial with co-existence of blaNDM-5 and blaOXA-181 in six CRKP, and blaNDM-5 and blaOXA-232 in one isolate, and chromosomal mutation of ompK36 and ompK37 in all twelve isolates. All the CRKP carried genes conferring resistance to 3rd generation cephalosporins, penicillin, aminoglycosides, fosfomycin, trimethoprim-sulfamethoxazole, and quinolones. The hybrid assemblies of 001BS and 002PS2 revealed that they harbored seven and six different plasmids, respectively. The 001BS carried two blaNDM-5 on distinct plasmids. The first blaNDM-5 gene was carried on an IncFIB(K) plasmid; and the second blaNDM-5 co-existed with blaOXA-181 on the ColPK3-IncX3 plasmid. In contrast, in 002PS2 the blaNDM-5 and blaOXA-181 were carried on the IncFIB(K)-IncFII(K) and ColPK3-IncX3 plasmids, respectively. The genetic environment of the blaNDM-5 gene on both plasmids was flanked by the same genetic core IS26-IS30-blaNDM-5 -ble-trpF-DsbD-ISCR1-sul1- QacE-IS3000.

CONCLUSION

Clonally related CRKP ST437 with multiple co-existing carbapenemase genes were detected for the first time at the tertiary hospital in Tanzania. The existence of this high-risk clone poses a great risk for further spread at our facility.

Emergence of blaOXA-181-bearing tigecycline-resistant Klebsiella aerogenes in China

We report the isolation of a blaOXA-181-positive, tigecycline-resistant Klebsiella aerogenes strain KA04 from a Chinese inpatient's fecal sample. Species identification was performed using MALDI-TOF MS. The antibiotic susceptibilities were assessed via the broth microdilution method. To elucidate the transmission and genetic structure of the blaOXA-181 gene, conjugation assays and whole-genome sequencing (WGS) were performed. KA04 displayed resistance to carbapenems, quinolones, piperacillin/tazobactam and tigecycline. Through WGS and conjugation experiments, it was possible to confirm blaOXA-181 and qnrS1 genes causing antibiotic resistance were located on a 51-kb IncX3 type mobile plasmid, blaOXA-181 gene could be successfully transferred into E. coli EC600 at a conjugation frequency of 1.1 × 10- 4. tet(A) gene was located on both the chromosome and non-transmissible IncFIB(K) plasmid. This is a tigecycline-resistant K. aerogenes harboring blaOXA-181 isolate from human fecal sample, highlighting a significant public health concern. Further comprehensive surveillance is needed.

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.