Diagnostic approach for detection and identification of emerging enteric pathogens revisited: the (Ali)arcobacter lanthieri case

An immunocompetent patient without a history of recent travel or animal exposure developed persistent abdominal bloating and cramps without diarrhoea or fever. Negative additional investigations excluded gastritis, infectious colitis, inflammatory bowel disease and neoplasia, but routine stool culture detected a Campylobacter-like organism. The isolate was obtained with use of a polycarbonate filter technique, emphasizing the importance of culture to support and validate the occurrence of emerging and new bacterial enteric pathogens. The ensuing extensive laboratory examinations proved challenging in identifying this potential pathogen. Phylogenetic marker analysis based on the 16S ribosomal RNA and rpoB gene sequences revealed that the isolate was most closely related to Arcobacter lanthieri and Arcobacter faecis. Subsequent analysis of a draft whole genome sequence assigned the isolate to A. lanthieri. We report the presence of five virulence genes, cadF, ciaB, mviN, hecA and iroE, indicating a possible pathogenic nature of this organism. This case demonstrated the importance of the use of agnostic methods for the detection of emerging pathogens in cases of enteric disease with a wide array of gastrointestinal symptoms.