title: Antimicrobial susceptibilities among clinical isolates of extended-spectrum cephalosporin-resistant Gram-negative bacteria in a Taiwanese University Hospital.
abstract: Infections caused by Gram-negative bacteria with resistance to extended-spectrum cephalosporins require the identification of effective alternative antimicrobial therapy. To determine the role of other pre-existing or currently available antimicrobial agents in treating infections caused by these multidrug-resistant pathogens, we evaluated the in vitro susceptibilities of these agents in 411 non-duplicate isolates of extended-spectrum cephalosporin-resistant Gram-negative bacteria recovered between January 1999 and December 1999 in a major teaching hospital in Taipei, Taiwan. These isolates included cefotaxime-resistant (MICs > or = 2 mg/L) Escherichia coli (66 isolates) and Klebsiella pneumoniae (77 isolates); cefotaxime-resistant (MICs > or = 64 mg/L) Enterobacter cloacae (59 isolates), Serratia marcescens (52 isolates) and Citrobacter freundii (52 isolates); and ceftazidime-resistant (MICs > or = 64 mg/L) Pseudomonas aeruginosa (50 isolates) and Acinetobacter baumannii (55 isolates). Overall, carbapenems (imipenem and meropenem) had good activity against the cefotaxime-resistant Enterobacteriaceae tested (>90% of isolates were susceptible). However, carbapenems had limited activity against the ceftazidime-resistant P. aeruginosa (only 4% of isolates were susceptible) and A. baumannii (51-56% of isolates were susceptible). Among the E. coli and K. pneumoniae isolates tested, 33.3% and 58.4%, respectively, exhibited extended-spectrum beta-lactamase phenotype, determined by the double disc method. Over 80% of cefotaxime-resistant E. cloacae and C. freundii were susceptible to cefepime, but this agent had limited activity against other bacteria tested. Susceptibilities of these isolates to ciprofloxacin varied, ranging from 25% for A. baumannii to 92% for E. cloacae. Newer fluoroquinolones (moxifloxacin and trovafloxacin) had equal or less activity against these organisms, except for A. baumannii for which their MIC(90)s (8-16 mg/L) were four- to 16-fold less than that of ciprofloxacin (MIC(90) 128 mg/L).
authors.affiliation: Section of Infectious Diseases, Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, 7 Chun-Shan South Road, Taipei, Taiwan.
authors.forename: Shio-Shin
authors.initials: SS
authors.lastname: Jean
authors.forename: Lee-Jene
authors.initials: LJ
authors.lastname: Teng
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
authors.forename: Shen-Wu
authors.initials: SW
authors.lastname: Ho
authors.forename: Kwen-Tay
authors.initials: KT
authors.lastname: Luh
mesh_terms: D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D018550:Cephalosporin Resistance / Q000502:physiology; D002511:Cephalosporins / Q000494:pharmacology*; D003428:Cross Infection / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004352:Drug Resistance, Microbial / Q000502:physiology; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy* / Q000453:epidemiology; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D013624:Taiwan / Q000453:epidemiology
chemical_list: D002511:Cephalosporins; D002442:Ceftazidime; D002439:Cefotaxime