DNA amplification fingerprinting (DAF) applied to the investigation of Acinetobacter baumanii isolated from intensive care unit patients.

Acinetobacter are important emerging nosocomial pathogens. In this paper thirteen Acinetobacter baumanii from intensive care patients were isolated. These were initially typed using the API-20 NE biotyping system and antibiogram analysis. Results obtained using these methods failed to convincingly characterise the organisms. In this report a method to characterise these Acinetobacter baumanii isolates is described, which utilises a modified polymerase chain reaction (PCR), capable of generating genomic fingerprints, known as DNA amplification fingerprinting (DAF). Purified chromosomal DNA of cultured clinical isolates of Acinetobacter baumanii were subjected to DAF using the M13 universal sequencing primer. Polymorphic DNA bands produced, were visualised after agarose gel electrophoresis and ethidium bromide staining. Results demonstrated that six of the thirteen clinical isolates represented one group and a second group of two isolates displayed identical fingerprint patterns. The remaining four organisms were all unique. This genotype based method is rapid, simple, reproducible and may have potential as a means of specifically typing Acinetobacter spp. allowing the route(s) of nosocomial transmission to be identified and to assess the efficiency of instituted infection control measures.