[Extended-spectrum beta-lactamase (ESBL) produced by Escherichia coli and Klebsiella pneumoniae isolated from Teikyou University Hospital--the first report].

We studied the cefotaxime (CTX)-resistant (MIC > or = 32 micrograms/ml) clinical isolates of E. coli and K. pneumoniae in Teikyo University Hospital from 1990 to 1996. The incidence of CTX-resistant isolates was 0.4% (6/1,282) in E. coli and 0.6% (7/1,044) in K. pneumoniae, in 1990. In 1995, the incidence of CTX-resistance increased to 1.7% (50/2,910) in E. coli (p = 0.0013) and 7.2% (144/1,996) in K. pneumoniae (p < 0.0001). These species have been detected in the stool (86 isolates), urine (59 isolates), sputum (15 isolates), pus (15 isolates), throat (10 isolates) and others (12 isolates) in 1995. MIC50 of ampicillin (ABPC), ABPC with clavlanic acid (CVA) 5 micrograms/ml, piperacillin (PIPC), PIPC with CVA 5 micrograms/ml, ceftazidime, CTX, ceftizoxime, cefpodoxime, cefepime, aztreonam, cefmetazole, latamoxef, and imipenem used against 33 isolates (11 isolates of E. coli, 22 isolates of K. pneumoniae), which were detected in 1996-1997, was > 512 micrograms/ml, 8 micrograms/ml, > 512 micrograms/ml, 8 micrograms/ml, 4 micrograms/ml, > 512 micrograms/ml, 16 micrograms/ml, > 512 micrograms/ml, 256 micrograms/ml, 32 micrograms/ml, 2 micrograms/ml, 0.25 microgram/ml and 0.25 microgram/ml, respectively. This susceptibility pattern were very similar to the Toho-1 type beta-lactamases producing strains.