Investigation of carbapenem-resistant Enterobacterales isolates at a tertiary laboratory in Pretoria, South Africa

Mbudzeni Ramashia, Thabiso D. Phofa, Granny M. Nkawane, Noel David Nogbou, John Y. Bolukaoto, Maphoshane Nchabeleng, Andrew M. Musyoki*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This study aimed to investigate phenotypic and genotypic characteristics of carbapenem-resistant Enterobacterales isolates (CRE) at a tertiary laboratory in South Africa. A total of 99 CRE isolates were collected between 2019 and 2021. Carbapenemase production was tested using modified carbapenem inhibitory method. Colistin susceptibility testing was performed using the ComASP™ Colistin broth microdilution method. Conventional PCR assays were conducted for detection of mcr-1 gene and common carbapenemase genes (blaVIM, blaNDM, blaIMP, blaKPC, blaOXA-23, blaOXA-51 and blaOXA-48). Rep-PCR assay was conducted to determine the genetic relatedness of the study isolates. Majority of the isolates were Klebsiella pneumoniae (83%). Carbapenem resistant K. pneumoniae cluster was observed from ICU and surgical ward samples. Colistin resistance was observed in 13% (12/93) of the isolates namely, in 11 K. pneumoniae and one Enterobacter cloacae. The blaOXA-48 (65%) was the most prevalent gene detected followed by blaNDM (25%) and blaVIM (22%). Several K. pneumoniae isolates concomitantly carried multiple carbapenemase genes with one isolate carry up to 5 five genes blaVIM, blaNDM, blaOXA-48, blaOXA-23 and blaOXA-51. The mcr-1 gene was not detected in the isolates. Rep-PCR assay showed that most isolates matched cluster A (50%). The high prevalence of blaOXA-48, blaNDM and emerging colistin resistant isolates is of concern for patient management at this institution and needs close monitoring. Rep-PCR is a valuable tool in establishing infection clusters in resource-limited settings.

Original languageEnglish
Pages (from-to)295-303
Number of pages9
JournalActa Microbiologica et Immunologica Hungarica
Volume70
Issue number4
DOIs
Publication statusPublished - 7 Dec 2023

Keywords

  • ICU
  • Klebsiella pneumoniae
  • antimicrobial resistance
  • carbapenem
  • carbapenem resistant Enterobacterales

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