PCR Assay Based on the gyrB Gene for Rapid Identification of Acinetobacter baumannii-calcoaceticus Complex at Specie Level

Background: The genus Acinetobacter sp. comprises more than 50 species, and four are closely related and difficult to be distinguished by either phenotypic or genotypic methods: the Acinetobacter calcoaceticus-baumannii complex (ABC). The correct identification at species level is necessary mainly due to the epidemiological aspects.

Methods: We evaluated a multiplex PCR for gyrB gene to identify the species of the ABC using the sequencing of the ITS 16S-23S fragment as a gold standard. Isolates identified as Acinetobacter calcoaceticus-baumannii from three hospitals at southern Brazil in 2011 were included in this study.

Results: A total of 117 isolates were obtained and 106 (90.6%) were confirmed as A. baumannii, 6 (5.1%) as A. nosocomialis and 4 (3.4%) as A. pittii by PCR for gyrB gene. Only one isolate did not present a product of the PCR for the gyrB gene; this isolate was identified as Acinetobacter genospecie 10 by sequencing of ITS. We also noted that the non-A. baumannii isolates were recovered from respiratory tract (8/72.7%), blood (2/18.2%) and urine (1/9.1%), suggesting that these species can cause serious infection.

Conclusion: These findings evidenced that the multiplex PCR of the gyrB is a feasible and simple method to identify isolates of the ABC at the species level.