[Investigation of ESBL types in community acquired urinary Escherichia coli isolates by isoelectric focusing and polymerase chain reaction]. / Toplum kaynakli üriner sistem enfeksiyonu etkeni Escherichia coli suslarinda GSBL enzim tiplerinin izoelektrik odaklama ve polimeraz zincir reaksiyonu yöntemleri ile arastirilmasi

ABSTRACT

The aim of this study was to determine the extended-spectrum beta-lactamase (ESBL) types by isoelectric focusing (IEF) 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.