Prevalence and antibiotic susceptibility of colistin-resistance gene (mcr-1) positive Enterobacteriaceae in stool specimens of patients attending a tertiary care hospital in Singapore

摘要

Objectives The aim of this study was to determine the prevalence of the colistin-resistance gene ( mcr-1 ) and the antibiotic-susceptibility profile of mcr-1 positive, colistin-resistant isolates in stool specimens of patients attending a tertiary care hospital in Singapore. Methods 201 diarrheal stool specimens of patients attending the Changi General Hospital between May to August 2017 were collected and screened for the presence of mcr-1 by culture and molecular methods. Antibiotic-susceptibility profile of mcr -1 positive isolates was determined using the polymyxin B and colistin E-tests and the VITEK 2 system. Results We observed an unexpectedly high prevalence of mcr-1 in patients attending a tertiary care hospital in Singapore, i.e 6.0% and 8.0% estimated by stool culture and direct stool PCR, respectively. The mcr-1 gene was detected predominantly in Escherichia coli . Antibiotic-susceptibility testing on 12 mcr-1 positive Enterobacteriaceae isolates revealed variable susceptibility profiles with no detection of carbapenem-resistant Enterobacteriaceae . Conclusions This is the first report of the prevalence of human faecal carriage of mcr- 1 in Singapore. Our findings highlight the potential risk of mcr- 1 spread among our patient cohort. The mcr-1 gene detection combined with the detection of other resistance gene targets of clinical importance is recommended to pre-empt the spread mcr-1 in our patients.