CTX-M and ampC β-lactamases contributing to increased prevalence of ceftriaxone-resistant Escherichia coli in Changi General Hospital, Singapore

Data from an 800-bed hospital showed an increase in the incidence density of ceftriaxone-resistant Escherichia coli, from 13.1 to 21.7 per 100 000 inpatient days over a 4-year period. Detailed testing performed on 54 E. coli isolates showed blaCTX-M extended-spectrum β-lactamase (ESBL) genes (n = 37) and blaCMY-likeampC genes (n = 15). Typing data showed only limited clonal transmission in isolates with ESBL.