Pseudooutbreak of Acinetobacter spp. Bacteriuria Confirmed by 16S rRNA Gene Sequence Analysis / 감염과화학요법

ABSTRACT

BACKGROUND: Acinetobacter spp. is increasingly implicated in hospital-acquired infections. We experienced a pseudooutbreak of Bordetella bronchiseptica bacteriuria identified with biochemical tests, that was later identified as Acinetobacter spp. by using 16S rRNA gene sequence analysis. MATERIALS AND METHODS: Five in-ward patients were found to have B. bronchiseptica bacteriuria without symptoms of urinary tract infection between September 23 and 26 of 2005. We conducted pulsed field gel electrophoresis (PFGE) of the bacteria and epidemiological investigation of this pseudooutbreak. In addition, 16S rRNA gene sequence analysis was performed for the verification of the strains. RESULTS: All 5 isolates were identified as B. bronchiseptica with similar antibiogram by VITEK system. There was no evidence of any symptom or sign of urinary tract infection. The source of this pseudooutbreak was not detected even after performing environmental culture and interviews with healthcare workers. We could not get the appropriate results from the first PFGE with XbaI restriction enzyme. B. bronchiseptica is an unusual organism in human so we conducted 16S rRNA gene sequence analysis for verification. The analysis of 16S rRNA gene sequence with 5 isolates demonstrated 99-100% similarity to a sequence of Acinetobacter spp. (AU1523). According to the results of 16S rRNA gene sequence analysis, we performed the second PFGE with SmaI restriction enzyme, which showed indistinguishable pattern among the all 5 isolates. CONCLUSION: This investigation suggests that the combined method of 16s rRNA gene sequence analysis and PFGE would be helpful for investigation of outbreak caused by unusual organisms