KPC-2-producing Klebsiella pneumoniae ST147 in a neonatal unit: Clonal isolates with differences in colistin susceptibility attributed to AcrAB-TolC pump
| Autor: | Bijan Saha, Sulagna Basu, Subhankar Mukherjee, Moidu Jameela Rameez, Timothy R. Walsh, Sharmi Naha, Chayan Roy, Shanta Dutta, Kirsty Sands |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Microbiology (medical) Klebsiella pneumoniae 030106 microbiology Virulence beta-Lactamases Microbiology 03 medical and health sciences Minimum inhibitory concentration 0302 clinical medicine Plasmid Bacterial Proteins Intensive Care Units Neonatal Drug Resistance Bacterial medicine polycyclic compounds Humans Pharmacology (medical) 030212 general & internal medicine Gene biology Colistin Infant Newborn General Medicine biochemical phenomena metabolism and nutrition biology.organism_classification bacterial infections and mycoses Anti-Bacterial Agents Klebsiella Infections SOXS Infectious Diseases bacteria Efflux Carrier Proteins medicine.drug |
| ISSN: | 0924-8579 |
| Popis: | This study characterizes four KPC-2-producing Klebsiella pneumoniae isolates from neonates belonging to a single sequence type 147 (ST147) in relation to carbapenem resistance and explores probable mechanisms of differential colistin resistance among the clonal cluster.\ud Whole genome sequencing (WGS) revealed that the isolates were nearly 100% identical and harbored resistance genes (blaKPC-2,OXA-9,CTX-M-15,SHV-11,OXA-1,TEM-1B, oqxA, oqxB, qnrB1, fosA, arr-2, sul1, aacA4, aac(6′)Ib-cr, aac(6′)Ib), and several virulence genes. blaKPC-2 was the only carbapenem-resistant gene found, bracketed between ISKpn7 and ISKpn6 of Tn4401b on a non-conjugative IncFII plasmid. Remarkably, one of the clonal isolates was resistant to colistin, the mechanistic basis of which was not apparent from comparative genomics. The transmissible colistin resistance gene, mcr, was absent. Efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) rendered a 32-fold decrease in the minimum inhibitory concentration (MIC) of colistin in the resistant isolate only. acrB, tolC, ramA, and soxS genes of the AcrAB-TolC pump system overexpressed exclusively in the colistin-resistant isolate, although the corresponding homologs of the AcrAB-TolC pump, regulators and promoters were mutually identical. No change was observed in the expression of other efflux genes (kpnE/F and kpnG/H) or two-component system (TCS) genes (phoP/phoQ, pmrA/pmrB).\ud Colistin resistance in one of the clonal KPC-2-producing isolates is postulated to be due to overexpression of the AcrAB-TolC pump. This study is probably the first to report clinical clonal K. pneumoniae isolates with differences in colistin susceptibility. The presence of carbapenem-resistant isolates with differential behavior in the expression of a genomically identical pump system indicates the nuances of the resistance mechanisms and the difficulty of treatment thereof. |
| Databáze: | OpenAIRE |
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