Identification of Arcobacter cryaerophilus isolated from a traffic accident victim with bacteremia by 16S ribosomal RNA gene sequencing

Traditional ways of identifying slow growing bacteria is slow and often dif ficult. In this study, a small, Gram-negative, facultative anaerobic, slow growing bacillus was isolated from the blood culture of a 7-year old traffi c accident victim. The bacterium was non-hemolytic, catalase and oxidase po sitive. An attempt to use the Vitek system (GNI+) and the API system (20NE) to identify the strain was unsuccessful as the growth controls showed nega tive results. 16S ribosomal RNA gene sequencing showed that there was I bas e difference between the isolate and Arcobacter cryaerophilus (GenBank Acce ssion no. U25805), I base difference between the isolate and A. cryaerophil us (GenBank Accession no. U34387), 10 base differences between the isolate and A. cryaerophilus (GenBank Accession no. L14624), 34 base differences be tween the isolate and A. butzleri (GenBank Accession no. U34386), 34 base d ifferences between the isolate and A. butzleri (GenBank Accession no. U3438 7), and 38 base differences between the isolate and A. butzleri (GenBank Ac cession no. L14626), indicating that the isolate most closely resembled a s train of A. cryaerophilus. Identification of the isolate in our case by con ventional methods was difficult, as the absence of a curved morphology has made it confused with other Gram-negative non-fermentative bacteria, and th e slow growth rate has made it unidentifiable by both the Vitek and API sys tems. Although the exact source of infection and route of transmission in o ur case remains elusive, we speculate that the bacteria were transmitted th rough the respiratory tract while the boy was suffocated in the mud. The pr esent report represents an example of showing the usefulness of 16S rRNA ge ne sequencing for identification of slow growing bacteria. (C) 2001 Elsevie r Science Inc. All rights reserved.