OXA-type carbapenemases in Acinetobacter baumannii in South America

Acinetobacter baumannii is an opportunistic pathogen that is frequently involved in outbreaks of infection, occurring mostly in intensive care units. The increasing incidence of carbapenem resistance in A. baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. The most important mechanism of carbapenem resistance is the enzymatic hydrolysis mediated by carbapenemases. In A. baumannii these enzymes are usually OXA-type carbapenemases, and belong to class D according to the classification of Ambler. The OXA-type carbapenemases are divided into five subgroups, four of which correspond to acquired carbapenemases, which accounts for the distribution of genes bla(OXA) in different geographic areas. In this work we review the different types of OXA-type carbapenemases present in A. baumannii, emphasizing the current situation in South America with special mention to the findings in Chile.