LSTM Home > LSTM Research > LSTM Online Archive

ChloS-HRM, a novel assay to identify chloramphenicol-susceptible Escherichia coli and Klebsiella pneumoniae in Malawi.

Downloads

Downloads per month over past year

Williams, Christopher, Musicha, Patrick, Feasey, Nicholas A, Adams, Emily ORCID: https://orcid.org/0000-0002-0816-2835 and Edwards, Thomas (2019) 'ChloS-HRM, a novel assay to identify chloramphenicol-susceptible Escherichia coli and Klebsiella pneumoniae in Malawi.'. The Journal of Antimicrobial Chemotherapy. (In Press)

[img]
Preview
Text
dky563.pdf - Published Version
Available under License Creative Commons Attribution.

Download (284kB) | Preview

Abstract

Objectives
Chloramphenicol is a broad-spectrum antimicrobial widely available in sub-Saharan Africa. With susceptibility re-emerging among Enterobacteriaceae in Blantyre, Malawi, we designed and evaluated a new high-resolution melt (HRM) RT-PCR assay, ChloS-HRM, to identify chloramphenicol-susceptible infections in a hospital setting.
Methods
Seventy-two previously whole-genome sequenced isolates of Escherichia coli and Klebsiella pneumoniae from the Queen Elizabeth Central Hospital, Malawi, were subjected to determination of chloramphenicol MICs. Primers were designed to detect 18 chloramphenicol resistance genes that produce seven distinct peaks correlating with different gene groups (catA1, catA2, catA3, catB2, catB group 3, cmlA and floR) following HRM analysis. ChloS-HRM results were compared with MIC and WGS results.
Results
ChloS-HRM correctly identified 15 of 17 phenotypically susceptible isolates and 54 of 55 resistant isolates, giving an accuracy of 88% in identifying susceptibility and 98% in identifying resistance. WGS identified 16 of 17 susceptible and 54 of 55 resistant isolates, giving an accuracy of 94% in identifying susceptibility and 98% in identifying resistance. The single false-susceptible result had no detectable gene by ChloS-HRM or WGS. Compared with WGS, ChloS-HRM had 100% sensitivity and specificity for catA (catA1-3), cmlA and floR, and 96% specificity for catB; sensitivity could not be estimated due to the lack of catB in the clinical sample collection. The overall agreement between MIC and HRM was 96% and between MIC and WGS it was 97%.
Conclusions
ChloS-HRM could support antimicrobial stewardship in enabling de-escalation from third-generation cephalosporins by identifying chloramphenicol-susceptible infections. This would be valuable in areas with chloramphenicol-susceptible MDR and XDR Enterobacteriaceae.

Item Type: Article
Subjects: QW Microbiology and Immunology > Bacteria > QW 138 Enterobacteriaceae
WA Public Health > Health Problems of Special Population Groups > WA 395 Health in developing countries
WC Communicable Diseases > Infection. Bacterial Infections > Bacterial Infections > WC 202 Pneumonia (General or not elsewhere classified)
WC Communicable Diseases > Infection. Bacterial Infections > Enteric Infections > WC 260 Enterobacteriaceae and other enteric infections
WC Communicable Diseases > Infection. Bacterial Infections > Enteric Infections > WC 290 Escherichia coli infections
WF Respiratory System > Lungs > WF 600 Lungs
Faculty: Department: Biological Sciences > Department of Tropical Disease Biology
Digital Object Identifer (DOI): https://doi.org/10.1093/jac/dky563
Depositing User: Stacy Murtagh
Date Deposited: 20 Feb 2019 10:26
Last Modified: 11 Apr 2019 09:39
URI: http://archive.lstmed.ac.uk/id/eprint/10186

Statistics

View details

Actions (login required)

Edit Item Edit Item