Oxacillinase detection in clinical isolates of carbapenem-resistant Acinetobacter baumannii from the State of São Paulo, Brazil

Abstract

Healthcare associated infections lead to increase of morbity and mortality, and can reflect in the costs of patients' management. Acinetobacter species, particularly Acinetobacter baumannii is associated with several kinds of nosocomial infections, and represent an important treat to infection control. They possess a large number of resistance mechanisms against virtually all available antimicrobial agents, including the carbapenems, which had been the longstanding last-line agents for treating Acinetobacter infections. A global increase in carbapenem-resistant Acinetobacter has been reported. The main mechanism associated with carbapenem resistance is the beta-lactamase production of OXA enzymes. The main variants of oxacillinases are those included in the groups OXA-23, OXA-51, OXA-24/40, OXA-58 and OXA-143. So far, there is any phenotipic test able to specifically detect the presence of oxacillinases, leading to the use of molecular techniques, such as the polymerase chain reaction, which presents high sensitivity and specificty. To determine the oxacillinase present in carbapenem-resistant A. baumannii can contribute for understanding the epidemiology of circulating strains. Thus, the aim of this study is to evaluate the presence of the oxacillinases encoding genes OXA-23, OXA-51, OXA-24/40, OXA-58 and OXA-143 groups in A. baumannii strains isolated from clinical specimens of hospitalized patients across the State of São Paulo, Brazil.