Vol.62 No.2 March 2014
Prevalence and drug-susceptibilities of extended-spectrum β-lactamase producing Escherichia coli strains isolated from urine
1)Department of Infectious Disease and Infection Control, The Jikei University Katsushika Medical Center, 6-41-2 Aoto, Katsushika-ku, Tokyo, Japan
2)Department of Urology, The Jikei University Katsushika Medical Center
3)Department of Infectious Disease and Infection Control, Jikei University School of Medicine
Abstract
We investigated the prevalence, drug susceptibilities of extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolated from urine and genotyping of ESBL, in order to clarify the strategies against urinary tract infection (UTIs) caused by ESBL producing E. coli. ESBL producing E. coli were isolated from 41 patients in The Jikei University Katsushika Medical Center from March 2010 to June 2012. Their median age was 76 years. Community-acquired infection cases numbered 19 (46.3%). Forty-one strains of ESBL producing E.coli were employed. Minimal inhibitory concentrations (MICs) of 17 antimicrobials, i.e., latamoxef (LMOX), flomoxef (FMOX), cefmetazole (CMZ), imipenem (IPM), meropenem (MEPM), doripenem (DRPM), faropenem (FRPM), sulbactam/ampicillin (SBT/ABPC), clavulanic acid/amoxicillin (CVA/AMPC), tazobactam/piperacillin (TAZ/PIPC), sulbactam/cefoperazone (SBT/CPZ), levofloxacin (LVFX), ciprofloxacin (CPFX), sitafloxacin (STFX), gentamicin (GM), amikacin (AMK) and tobramycin (TOB), against these strains were measured using the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). In addition, genotyping of ESBLs was determined using PCR. As for genotyping of ESBLs, the CTX-M-9 group, the CTX-M-1 group and the CTX-M-2 group comprised 31 strains (75.6%), 6 (14.6%) and 4 (9.8%), respectively. All strains were sensitive to MEPM, DRPM, IPM, TAZ/PIPC, LMOX, FMOX, CMZ, FRPM and AMK. Seventy-three percent of these strains was sensitive to STFX. However, 73.2% of these strains was LVFX-resistant. These results indicated that members of the ESBL producing E. coli family were frequently LVFX-resistant. Therefore, in the future we should pay attention to the choice of antimicrobials for UTIs caused by ESBL producing E. coli with continuous investigation of their drug-susceptibilities.
Key word
extended-spectrum β-lactamase, Escherichia coli , minimal inhibitory concentration, urinary tract infection
Received
November 19, 2013
Accepted
January 10, 2014
Jpn. J. Chemother. 62 (2): 198-203, 2014
