[Epidemiologic consistency of polymerase chain reaction (PCR) based methods for the study of Acinotobacter baumannii...

Acinetobacter baumannii is one of the most frequent causative agents of nosocomial infections outbreaks. Consequently, a rapid and specific typing method that can identify epidemic strains is important in preventing their dissemination. To evaluate PCR (polymerase chain reaction)-based methods as epidemiological markers, epidemiologic concordance (EC) and the discriminatory power (D) of two of those methods: 1) arbitrary primed-PCR (AP-PCR), and 2) repetitive extragenic palindrome sequence-based PCR (REP-PCR), were analyzed. The results were compared with that of ribotyping using EcoRI, BglII and ClaI as restriction enzymes. These methods were applied to 69 A. baumannii isolates that included: 15 epidemiological unrelated isolates, 31 recovered from two outbreaks, and 23 obtained from endemic infections. Considering the unrelated isolates, D of ribotyping, AP-PCR and REP-PCR were 0.915, 0.904 and 0.847, respectively. The three methods showed the same EC with respect to the two analyzed outbreaks (100% and 83%, respectively), and the epidemic strains were uniformi differentiated from the co-transferred ones. Ribotyping classified the 23 isolates recovered from endemic infections in 4 different strains, while AP-PCR and REP-PCR identified 3 of them. Although, the 3 methods identified the most frequent disseminated strain. The mayor advantages of REP-PCR versus AP-PCR were reproducibility, and easier optimization. These advantages, in addition to the similar EC of the 3 methods, confirm REP-PCR as an appropriate marker to be used when rapid information about epidemiological A. baumannii infection analysis is required.