[[alternative]]Bacteremia due to extended-spectrum-β-lactamase-producing enterobacter cloacae: role of carbapenem therapy

[[abstract]]Enterobacter cloacae is one of important nosocomial pathogens. However, few studies specifically dealing with clinical characteristics and outcome of extended-spectrum beta-lactamase (ESBL)-producing E. cloacae infections have been published. During an eight-year period in a medical center, of 610 E. cloacae bacteremic isolates, 138 (22.6 %) with ESBL genes were designated as the ESBL group; and 120 (19.6 %) with cefotaxime-nonsusceptible without ESBL phenotype and genes as the control group. Of the former isolates, 133 (96.3%) had blaSHV-12, three (2.1%) blaCTX-M3, and two (1.4%) both blaSHV-12 and blaCTX-M3. After exclusion of age <18 year, there were 206 adults with E. cloacae bacteremia, 121 patients in the ESBL group and 85 in the control group. More episodes of hospital-onset and polymicrobial bacteremia, increased severity of illness, more bacteremic onset in intensive care units (ICUs), and longer stay in the hospital and ICU after bacteremic onset, were noted in the ESBL group. However, the crude and sepsis-related mortality rates in two groups were similar. Of the ESBL group, the in-hospital sepsis-related mortality rate of patients definitively treated by a carbapenem was lower than that of those by non-carbapenem ss-lactams (5/53, 9.4% vs. 13/44, 29.5%; P=0.01), though the difference was not significant in the hierarchical multivariate analysis (P=0.46). Among 62 patients with follow-up blood cultures within 14 days of bacteremic onset, breakthrough bacteremia was more common in those treated by a non-carbapenem beta-lactam agent than those treated by a carbapenem (18/31, 58.0% vs. 3/31, 9.6%; P