The Occurrence of blaCTX-M, blaSHV, and blaTEM Genes in Extended-Spectrum β-Lactamase-Positive Strains of Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis in Poland

Abstract EN

Bacteria belonging to the Enterobacteriaceae family that produce extended-spectrum β-lactamase (ESBL) enzymes are important pathogens of infections.

Increasing numbers of ESBL-producing bacterial strains exhibiting multidrug resistance have been observed.

The aim of the study was to evaluate the prevalence of blaCTX-M, blaSHV, and blaTEM genes among ESBL-producing Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis strains and to examine susceptibility to antibiotics of tested strains.

In our study, thirty-six of the tested strains exhibited blaCTX-M genes (blaCTX-M-15, blaCTX-M-3, blaCTX-M-91, and blaCTX-M-89).

Moreover, twelve ESBL-positive strains harbored blaSHV genes (blaSHV-18, blaSHV-7, blaSHV-2, and blaSHV-5), and the presence of a blaTEM gene (blaTEM-1) in twenty-five ESBL-positive strains was revealed.

Among K.

pneumoniae the multiple ESBL genotype composed of blaCTX-M-15, blaCTX-M-3, blaSHV-18, blaSHV-7, blaSHV-2, and blaSHV-5 genes encoding particular ESBL variants was observed.

Analysis of bacterial susceptibility to antibiotics revealed that, among β-lactam antibiotics, the most effective against E.

coli strains was meropenem (100%), whereas K.

pneumoniae were completely susceptible to ertapenem and meropenem (100%), and P.

mirabilis strains were susceptible to ertapenem (91.7%).

Moreover, among non-β-lactam antibiotics, gentamicin showed the highest activity to E.

coli (91.7%) and ciprofloxacin the highest to K.

pneumoniae (83.3%).

P.

mirabilis revealed the highest susceptibility to amikacin (66.7%).