OXA-181-Like Carbapenemases in Klebsiella pneumoniae ST14, ST15, ST23, ST48, and ST231 from Septicemic Neonates: Coexistence with NDM-5, Resistome, Transmissibility, and Genome Diversity.

Studies on the epidemiology and genomes of isolates harboring OXA-48-like genes in septicemic neonates are rare. Here, isolates producing these carbapenemases which emerged and persisted in an Indian neonatal unit were characterized in terms of their resistome, transmissibility, and genome diversity. Antibiotic susceptibility and whole-genome sequencing were carried out. The sequence types, resistome, virulome, mobile genetic elements, and transmissibility of carbapenem-resistant plasmids were evaluated. Core genome analysis of isolates was shown in a global context with other OXA-48-like carbapenemase-harboring genomes, including those from neonatal studies. Eleven OXA-48-like carbapenemase-producing Klebsiella pneumoniae (blaOXA-181, n = 7 and blaOXA-232, n = 4) isolates belonging to diverse sequence types (ST14, ST15, ST23, ST48, and ST231) were identified. blaOXA-181/OXA-232 and blaNDM-5 were found in a high-risk clone, ST14 (n = 4). blaOXA-181/OXA-232 were in small, nonconjugative ColKP3 plasmids located on truncated Tn2013, whereas blaNDM-5 was in self-transmissible, conjugative IncFII plasmids, within truncated Tn125 Conjugal transfer of blaOXA-181/OXA-232 was observed in the presence of blaNDM-5 The study strains were diverse among themselves and showed various levels of relatedness with non-neonatal strains from different parts of the world and similarity with neonatal strains from Tanzania and Ghana when compared with a representative collection of carbapenemase-positive K. pneumoniae strains. We found that blaOXA-181/OXA-232-harboring isolates from a single neonatal unit had remarkably diverse genomes, ruling out clonal spread and emphasizing the extent of plasmid spreading across different STs. This study is probably the first to report the coexistence of blaOXA-181/232 and blaNDM-5 in neonatal isolates.IMPORTANCE Neonatal sepsis is a leading cause of neonatal mortality in low- and middle-income countries (LMICs). Treatment of sepsis in this vulnerable population is dependent on antimicrobials, and resistance to these life-saving antimicrobials is worrisome. Carbapenemases, enzymes produced by bacteria, can make these antimicrobials useless. Our study describes how OXA-48-like carbapenemases in neonatal septicemic Klebsiella pneumoniae shows remarkable diversity in the genomes of the strains and relatedness with strains from other parts of world and also to some neonatal outbreak strains. It is also the first to describe such resistance due to coproduction of dual carbapenemases, (OXA)-48 and New Delhi metallo-β-lactamase-5, in Klebsiella pneumoniae from neonatal settings. Carbapenemase genes situated on plasmids within high-risk international clones, as seen here, increase the ease and transfer of resistant genetic material. With the WHO treatment protocols not adequately poised to handle such infections, prompt attention to neonatal health care is required.

Naha S ，Sands K ，Mukherjee S ，Saha B ，Dutta S ，Basu S ... -  《mSphere》

Rapidly disseminating bla(OXA-232) carrying Klebsiella pneumoniae belonging to ST231 in India: multiple and varied mobile genetic elements.

Shankar C ，Mathur P ，Venkatesan M ，Pragasam AK ，Anandan S ，Khurana S ，Veeraraghavan B ... -  《BMC MICROBIOLOGY》

Dissemination and Stability of the bla(NDM-5)-Carrying IncX3-Type Plasmid among Multiclonal Klebsiella pneumoniae Isolates.

NDM-5 carbapenemase was mainly identified in Escherichia coli, while the rapid transmission of blaNDM-5 among Enterobacteriaceae has raised serious public attention. This study identified 14 NDM-5-producing Klebsiella pneumoniae isolates from 107 carbapenem-resistant K. pneumoniae isolates, recovered from blood, urine, and normally sterile body fluids of pediatric patients from January 2016 to December 2018. All NDM-5-producing isolates were highly resistant to β-lactams, while tigecycline and polymyxin B exhibited excellent antimicrobial activity. These 14 strains belonged to 9 different sequence types (STs) and displayed various pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they were not clonally related. S1-PFGE followed by Southern blotting showed that the blaNDM-5 gene was located on an ∼46-kb IncX3 plasmid in all strains. All blaNDM-5-carrying plasmids were successfully transferred into recipient E. coli J53. PCR-based sequencing demonstrated that all of the blaNDM-5-carrying plasmids shared highly similar backbones, with nucleotide sequence identity of >99%. Moreover, this plasmid displayed high sequence similarity to the previously reported epidemic IncX3 blaNDM-5-carrying plasmids, with dynamic changes observed only in blaNDM-5-surrounding elements. Interestingly, the IncX3 blaNDM-5-carrying plasmids showed strong stability in clinical isolates when cultured in antibiotic-free medium. However, after the conjugation inhibitor linoleic acid was added, a gradual increase in the level of IncX3 plasmid loss could be observed. Clinical isolates displayed 10% to 15% blaNDM-5-carrying plasmid loss after coculture with linoleic acid for 5 days. These results showed that the IncX3 plasmid facilitated the dissemination of blaNDM-5 among multiclonal K. pneumoniae strains in children and that conjugal transfer contributed significantly to IncX3 plasmid stability within K. pneumoniaeIMPORTANCE The emergence and spread of New Delhi metallo-β-lactamase (NDM)-producing Enterobacteriaceae have been a serious challenge to public health, and NDM-5 shows increased resistance to carbapenems compared with other variants. NDM-5 has been identified mostly in E. coli but has rarely been described in K. pneumoniae and other Enterobacteriaceae isolates. Here, we present the dissemination of highly similar 46-kb IncX3 blaNDM-5-carrying plasmids among multiclonal K. pneumoniae strains in children, highlighting the horizontal gene transfer of blaNDM-5 among K. pneumoniae strains via the IncX3 plasmid. Moreover, the IncX3 blaNDM-5-carrying plasmids displayed strong stability in clinical strains when cultured in antibiotic-free medium, and the plasmid maintenance was attributed partly to conjugal transfer. Plasmid conjugation is mediated by the type IV secretion system (T4SS), and T4SS is conserved among all epidemic IncX3 blaNDM-5-carrying plasmids. Therefore, combining conjugation inhibition and promotion of plasmid loss would be an effective strategy to limit the conjugation-assisted persistence of IncX3 blaNDM-5-carrying plasmids.

Zhu W ，Wang X ，Qin J ，Liang W ，Shen Z ... -  《mSphere》

Clinical and Molecular Description of a High-Copy IncQ1 KPC-2 Plasmid Harbored by the International ST15 Klebsiella pneumoniae Clone.

This study provides the genomic characterization and clinical description of bloodstream infections (BSI) cases due to ST15 KPC-2 producer Klebsiella pneumoniae Six KPC-K. pneumoniae isolates were recovered in 2015 in a tertiary Brazilian hospital and were analyzed by whole-genome sequencing (WGS) (Illumina MiSeq short reads). Of these, two isolates were further analyzed by Nanopore MinION sequencing, allowing complete chromosome and plasmid circularization (hybrid assembly), using Unicycler software. The clinical analysis showed that the 30-day overall mortality for these BSI cases was high (83%). The isolates exhibited meropenem resistance (MICs, 32 to 128 mg/liter), with 3/6 isolates resistant to polymyxin B. The conjugative properties of the blaKPC-2 plasmid and its copy number were assessed by standard conjugation experiments and sequence copy number analysis. We identified in all six isolates a small (8.3-kb), high-copy-number (20 copies/cell) non-self-conjugative IncQ plasmid harboring blaKPC-2 in a non-Tn4401 transposon. This plasmid backbone was previously reported to harbor blaKPC-2 only in Brazil, and it could be comobilized at a high frequency (10-4) into Escherichia coli J53 and into several high-risk K. pneumoniae clones (ST258, ST15, and ST101) by a common IncL/M helper plasmid, suggesting the potential of international spread. This study thus identified the international K. pneumoniae ST15 clone as a carrier of blaKPC-2 in a high-copy-number IncQ1 plasmid that is easily transmissible among other common Klebsiella strains. This finding is of concern since IncQ1 plasmids are efficient antimicrobial resistance determinant carriers across Gram-negative species. The spread of such carbapenemase-encoding IncQ1 plasmids should therefore be closely monitored.IMPORTANCE In many parts of the world, carbapenem resistance is a serious public health concern. In Brazil, carbapenem resistance in Enterobacterales is mostly driven by the dissemination of KPC-2-producing K. pneumoniae clones. Despite being endemic in this country, only a few reports providing both clinical and genomic data are available in Brazil, which limit the understanding of the real clinical impact caused by the dissemination of different clones carrying blaKPC-2 in Brazilian hospitals. Although several of these KPC-2-producer K. pneumoniae isolates belong to the clonal complex 258 and carry Tn4401 transposons located on large plasmids, a concomitant emergence and silent dissemination of small high-copy-number blaKPC-2 plasmids are of importance, as described in this study. Our data identify a small high-copy-number IncQ1 KPC plasmid, its clinical relevance, and the potential for conjugative transfer into several K. pneumoniae isolates, belonging to different international lineages, such as ST258, ST101, and ST15.

Martins WMBS ，Nicolas MF ，Yu Y ，Li M ，Dantas P ，Sands K ，Portal E ，Almeida LGP ，Vasconcelos ATR ，Medeiros EA ，Toleman MA ，Walsh TR ，Gales AC ，Andrey DO ... -  《mSphere》

Characterization of Carbapenem-Resistant Enterobacteriaceae Clinical Isolates in Al Thawra University Hospital, Sana'a, Yemen.

Alsharapy SA ，Gharout-Sait A ，Muggeo A ，Guillard T ，Cholley P ，Brasme L ，Bertrand X ，Moghram GS ，Touati A ，De Champs C ... -  《-》