TY - JOUR
T1 - Colistin Resistance Mechanisms in Clinical Escherichia coli and Klebsiella spp. Isolates from the Western Cape of South Africa
AU - Snyman, Yolandi
AU - Whitelaw, Andrew Christopher
AU - Reuter, Sandra
AU - Maloba, Motlatji Reratilwe Bonnie
AU - Newton-Foot, Mae
N1 - Funding Information:
This work was supported by the NHLS Research Trust and personal funding was obtained by the NRF Innovation Masters Scholarship. The funders had no role in study design, data collection, analysis and interpretation, decision to submit the work for publication, or preparation of the article.
Publisher Copyright:
© Copyright 2021, Mary Ann Liebert, Inc., publishers 2021.
PY - 2021/9/1
Y1 - 2021/9/1
N2 - Objectives: Colistin is a last-resort antibiotic for the treatment of carbapenem-resistant Gram-negative infections. Colistin resistance thus poses a threat to human health. Colistin resistance is most commonly encoded by mutations in chromosomal pmrA, pmrB, phoP, phoQ, ccrB, and mgrB genes, and the presence of plasmid-mediated mcr genes. This study describes colistin resistance mechanisms in clinical Enterobacterales isolates from the Western Cape, South Africa. Results: Escherichia coli (n = 22) and Klebsiella spp. (n = 7) isolates, from nine health care facilities, were confirmed to be colistin resistant during 2016 and 2017. mcr-1 was present in 55% (12/22) of E. coli and 71% (5/7) of Klebsiella spp. isolates. Colistin resistance mutations in pmrB were identified in 8/10 mcr-negative E. coli isolates using whole-genome sequencing, with pmrB Pro-94→Gln being the most frequent with presence in 4 isolates. One mcr-negative Klebsiella spp. isolate had a complete deletion of the mgrB and one contained an insertion sequence (IS1) in mgrB. Conclusion: A reduction in the proportion of colistin-resistant isolates harboring mcr-1 from 2016 to 2017 was observed. Colistin-resistant E. coli attributed by chromosomal mutations in pmrB in 2017 were mostly clonal related, which contrasts with the 2016 unrelated mcr-1-positive isolates. The diverse strains, hospitals, and resistance mechanisms may suggest that selective pressure is the main driver of colistin resistance.
AB - Objectives: Colistin is a last-resort antibiotic for the treatment of carbapenem-resistant Gram-negative infections. Colistin resistance thus poses a threat to human health. Colistin resistance is most commonly encoded by mutations in chromosomal pmrA, pmrB, phoP, phoQ, ccrB, and mgrB genes, and the presence of plasmid-mediated mcr genes. This study describes colistin resistance mechanisms in clinical Enterobacterales isolates from the Western Cape, South Africa. Results: Escherichia coli (n = 22) and Klebsiella spp. (n = 7) isolates, from nine health care facilities, were confirmed to be colistin resistant during 2016 and 2017. mcr-1 was present in 55% (12/22) of E. coli and 71% (5/7) of Klebsiella spp. isolates. Colistin resistance mutations in pmrB were identified in 8/10 mcr-negative E. coli isolates using whole-genome sequencing, with pmrB Pro-94→Gln being the most frequent with presence in 4 isolates. One mcr-negative Klebsiella spp. isolate had a complete deletion of the mgrB and one contained an insertion sequence (IS1) in mgrB. Conclusion: A reduction in the proportion of colistin-resistant isolates harboring mcr-1 from 2016 to 2017 was observed. Colistin-resistant E. coli attributed by chromosomal mutations in pmrB in 2017 were mostly clonal related, which contrasts with the 2016 unrelated mcr-1-positive isolates. The diverse strains, hospitals, and resistance mechanisms may suggest that selective pressure is the main driver of colistin resistance.
KW - Enterobacterales
KW - South Africa
KW - colistin resistance
KW - mutations
KW - whole genome sequencing
UR - http://www.scopus.com/inward/record.url?scp=85103310186&partnerID=8YFLogxK
U2 - 10.1089/mdr.2020.0479
DO - 10.1089/mdr.2020.0479
M3 - Article
C2 - 33571049
AN - SCOPUS:85103310186
SN - 1076-6294
VL - 27
SP - 1249
EP - 1258
JO - Microbial Drug Resistance
JF - Microbial Drug Resistance
IS - 9
ER -