[Investigation of ESBL types in community acquired urinary Escherichia coli isolates by isoelectric focusing and polymerase chain reaction].
The aim of this study was to determine the extended-spectrum beta-lactamase (ESBL) types by isoelectric focusing (İEF) and polymerase chain reaction (PCR) methods in 56 Escherichia coli strains isolated from urine samples of patients with community-acquired urinary tract infection and determined as ESBL positive with the phenotypic screening tests (E test and combined disk method). IEF revealed that most of the strains produced 1 to 3 different bands, mostly at the isoelectric points 8.2 (n= 44, 79%) compatible with CTX-M. Twenty four (43%) isolates had CTX-M and TEM enzyme bands together, 16 (29%) isolates had only CTX-M enzyme bands, 3 (5%) isolates had CTX-M, TEM, SHV bands, one had CTX-M and SHV enzyme bands together, and one had only TEM band. Eleven E.coli strains did not yield any enzyme bands. PCR analysis revealed that 93% (n= 52) of the isolates had CTX-M, 64% (n= 36) had TEM and 11% (n= 6) had SHV, while 29 (52%) had CTX-M + TEM, three had CTX-M + SHV, and three had CTX-M + TEM + SHV genes together. PER-1 type beta-lactamases were not detected by PCR method. PCR analysis of the eleven strains that yielded no band in IEF showed that 5 strains had CTX-M + TEM, 3 had CTX-M and 3 had TEM enzyme genes. The consistency between IEF and PCR methods for the determination of CTX-M, TEM and SHV enzymes was 85%, 78% and 67%, respectively. Genes encoding ESBL's are usually located on transferrable plasmids that may also carry other resistance determinants. Thus detection of beta-lactamase enzyme types in ESBL positive bacteria is important for the choice of appropriate antimicrobial agents for treatment.
Akdeniz Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı, Antalya, Türkiye.
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Gültekin
D017714:Community-Acquired Infections / Q000382:microbiology; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology*; D006801:Humans; D007525:Isoelectric Focusing; D016133:Polymerase Chain Reaction; D014552:Urinary Tract Infections / Q000382:microbiology*; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001618:beta-Lactamases