Appearance of bacilli belonging to Enterobacteriaceae family producing β-lactamases (ESβ L and AmpC) isolated from infections on the grounds of the Institute of Rheumatology in years 2006-2008

Studies have been done on 494 strains of bacilli belonging to the family Enterobacteriaceae (including 77% Escherichia coli) isolated from patients with infections (mainly urinary tract and wounds/abscesses) hospitalized in four clinics of the Institute of Rheumatology in years 2006-2008. The aim of the research was to use methodology recommended by the National Reference Centre for Drug Resistance to find strains producing β-lactamase enzymes, plasmid-encoded (ESβL) and chromosomally encoded (AmpC), hydrolyzing (or splitting hydrolytically) most β-lactamase antibiotics, widely applied in experimental and targeted therapy.
Analysis of the results:
• great diversity (11 of 20 isolated species of Enterobacteriaceae family) of species producing above-mentioned enzymes, but generally low frequency (range 5.6% – ESβL and 1.4% – AmpC) in whole tested group,
• indicated enzymes in about 16% lead to multi-drug resistance (MLDR) of tested bacteria, but in some (Proteus sp., Enterobacter sp., and Klebsiella sp.) it was probably a decisive causative factor of MLDR,
• investigations of appearance of strains producing the above-mentioned β-lactamases play an important role in setting the direction of therapy of infections with Enterobacteriaceae suspected aetiology, because discovery of these enzymes is changing diametrically the clinical interpretation of resistance to β-lactamase, independently of results obtained in tests done in vitro,
• in particular clinics the frequencies of isolated microbes belonging to the Enterobacteriaceae family producing these enzymes differ, and this has epidemiological and prognostic importance.