Activity of ertapenem, ciprofloxacin, ceftriaxone, piperacillin-tazobactam, and ampicillin-sulbactam against 12 common clinical isolates of community-acquired bacteremia.

BACKGROUND AND PURPOSE To compare the antimicrobial activities of ertapenem, ciprofloxacin, ceftriaxone, piperacillin-tazobactam, and ampicillin-sulbactam against 12 common organisms that cause community-acquired bacteremia and to identify the most active agents for the treatment of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae. METHODS 1200 blood specimens from patients with community-acquired bacteremia were collected at Chang Gung Memorial Hospital, Kaohsiung, Taiwan. All isolates were identified by the API system, and each culture's antimicrobial susceptibility was determined by the standard disk-diffusion method. The minimal inhibitory concentrations of the antibiotics were detected by the Epsilimeter test. RESULTS The in vitro susceptibilities of 11 of the 12 common pathogens to ertapenem were 100%. The frequency of ESBL-producing E. coli and K. pneumoniae was 6.2% and 9.5%, respectively. Only 48% and 50% of E. coli and K. pneumoniae, respectively, were susceptible to ciprofloxacin. These data infer that ciprofloxacin should not be given for ESBL-producing E. coli and K. pneumoniae. Ceftriaxone and piperacillin-tazobactam had high activity against the most common pathogens isolated. CONCLUSIONS ESBL E. coli and K. pneumoniae are highly resistant to ciprofloxacin, so this antibiotic should be avoided for patients with community-acquired bacteremia. ESBL E. coli and K. pneumoniae are highly susceptible to ertapenem.