Abstract

CUAICAL RAMOS, Nirvia Margot et al. Detection of OXA type carbapenemases in Acinetobacter baumannii from different hospital centers in Caracas, Venezuela. Rev. Soc. Ven. Microbiol. [online]. 2012, vol.32, n.2, pp.95-110. ISSN 1315-2556.

It has become increasingly frequent to detect nosocomial carbapenem-resistant Acinetobacter baumannii isolates. In this study we detected OXA type carbapenemases in 60 A. baumannii isolates from different health centers in Caracas. The identification was done in a conventional fashion and by PCR through detection of bla_OXA-51-like as a A. baumannii species marker. The susceptibility profile was done with the Kirby Bauer method according to CLSI 2009 guidelines; enzymatic activity against carbapenems was evaluated through microbiological tests; molecular detection of bla_OXA-23-like and bla_OXA-58-like was done by PCR. Genes that codify for OXA type carbapenemases were detected in 96.6% of the isolates; of these, 93.4% showed bla_OXA-23-like and 6.6% bla_OXA-58-like. In 3.3% of the positive isolates coexistence of bla_OXA-23-like and bla_OXA-58-like was detected. Detection of bla_OXA-23-like in most of the carbapenem resistant isolates indicates that it is a determining factor in the resistance of these antimicrobials; consequently, more than one gene codifying for OXA type carbapenemases can be detected in A. baumannii, the one presented intrinsically (bla_OXA-51), and those which are acquired (bla_OXA-23 and bla_OXA-58).

Keywords : Acinetobacter; Venezuela; resistance; carbapenemes.

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