1. Wprowadzenie. 2. Mechanizmy oporności bakterii na antybiotyki β-laktamowe. 3. Klasyfikacja β-laktamaz. 4. β-Laktamazy gatunkowo-specyficzne. 5. β-Laktamazy nabyte. 6. Ekspresja β-laktamaz. 7. Najważniejsze grupy β-laktamaz nabytych. 7.1. β-Laktamazy o rozszerzonym spektrum substratowym, ESBL. 7.2. Cefalosporynazy AmpC. 7.3. Karbapenemazy. 7.3.1. Karbapenemazy klasy A 7.3.2. Karbapenemazy klasy B. 7.3.3. Karbapenemazy klasy D. 8. Podsumowanie

Abstract: Production is β-Lactamase the major mechanism of resistance to β-lactams in Gram-negative bacteria. In recent years, resistance due to production of β-lactamases has been increasing at on alarming rate. It refers mostly to extended-spectrum β-lactamases (ESBLs) that are the main problem in microorganisms of the family Enterobacteriaceae, conferring resistance to all penicillins, cephalosporins (except for cephamycins) and monobactams. Acquired cephalosporinases of the AmpC type also have become a significant factor of enterobacterial resistance to newer generation of β-lactams. The effect of AmpCs is largely strengthened by this mutational overexpression in such pathogens as Enterobacter spp. or Citrobacter freundii. β-Lactamase-mediated resistance to carbapenems in the members of the family Enterobacteriaceae has become a matter of highest concern over the last decade. It has been associated with various carbapenemhydrolyzing enzymes, including the so-called KPC, MBL or OXA-48 types. Antimicrobial resistance in bacteria has been a key issue in public health, requiring constant monitoring at the hospital, country and global level.

1. Introduction. 2. Mechanisms of resistance to β-lactam antibiotics. 3. Classification of β-lactamases. 4. Natural β-lactamases. 5. Acquired β-lactamases. 6. Expression of β-lactamases. 7. Main groups of the acquired β-lactamases. 7.1. Extended-spectrum β-lactamases, ESBLs. 7.2. AmpC-type cephalosporinases. 7.3. Carbapenemases. 7.3.1. Class A carbapenemases. 7.3.2. Class  B
carbapenemases. 7.3.3. Class D carbapenemases. 8. Conclusions