Extended-Spectrum β-Lactamases Producing Escherichia coli Strains Monitored Over 4 Years in The University Hospital in Košice, Slovakia

The beta-lactamases with extended spectrum of activity (ESBL) are medically one of the most important group of enzymes. The presented study provides identification and determination of the spectrum of resistance against different and clinically used antimicrobial drugs in the clinical isolates of Escherichia coli. These isolates had their origin in different departments of the University Hospital L. Pasteur in Košice. The second goal was the detection of beta-lactamase production with extended-spectrum effect (ESBL) and testing of AmpC-type cephalosporinases by several phenotypic tests in clinical isolates. We used both the microdilution method and the method with an active agent, respectively. Samples were positively tested for ESBL with the use of the CLSI disk diffusion method. PCRs were performed with a series of primers designed for the detection of Ambler class A, B and C beta-lactamase genes. About 307 strains of E. coli were investigated. The growth of E. coli resistance to selected antibiotics was present in 83.25% of clinical isolates. There were identified 85 positive isolates in the studied group and the prevalence of the ESBL positive strains of E. coli reached 27.78%. An E. coli strain was isolated with mutations in the promoter region of the AmpC chromosomal gene that is associated with overproduction of the relevant enzyme. We describe a complex ESBL epidemiology. The study revealed a high rate of ESBL-producing E. coli isolates. The bla_TEM and bla_SHV enzymes dominated in ESBL-positive E. coli isolates in the University Hospital L. Pasteur in Košice.