Incidence of Colistin Resistance among Carbapenem-resistant Enterobacterales Isolated from Clinical Specimens in Prapokklao Hospital, Thailand

Abstract

The incidence of colistin resistance among Enterobacterales is increasing. Clinical and Laboratory Standards Institute (CLSI) has recently released the colistin resistance detection guideline in carbapenem-resistant Enterobacterales (CRE) by colistin broth disk elution (CBDE) method which is easy and inexpensive. The objective of this study was to investigate the incidence of colistin-resistant Enterobacterales isolated from clinical specimens at Prapokklao Hospital from January to December 2021. A total of 210 isolates, non-duplicated and carbapenem-resistant Enterobacterales specimens were used in this study. CBDE was used for colistin testing. Thirty-seven and one hundred seventy-three carbapenem-resistant isolates were resistant and intermediate to colistin respectively. Klebsiella pneumoniae were mostly resistant (35 isolates) and intermediate to colistin (153 isolates) respectively. One isolate each of Citrobacter freundii and Klebsiella aerogenes were found to be resistant to colistin. Colistin resistance was not found in Escherichia coli, Enterobacter cloacae and Citrobacter diversus. The proportion of colistin-resistant and intermediate to colistin strains was found to highly correlate to the old-age group. Colistin resistance was commonly found in the medicine ward, dermatology and subcutaneous tissue groups. Most lethal patients were infected by colistin-intermediate      K. pneumoniae. This study informed useful information concerning the treatment, prevention and control of colistin-resistant microorganisms in hospital.