Specific detection of Arcobacter spp. in estuarine waters of Southern Italy by PCR and fluorescent in situ hybridization

Aim: To evaluate the reliability of culture-independent methods in comparison with culture-dependent ones for the detection of Arcobacter spp. in estuarine waters of Southern Italy. Methods and Results: PCR and fluorescent in situ hybridization (FISH) procedures were used to detect arcobacters directly in water samples and after enrichment cultures. The samples totally were positive by molecular methods (PCR and FISH) but only 75% were culture positive, confirming the limitation of these latter to detect Arcobacter spp. in natural samples. Culturable arcobacters were retrieved in all times except in July, and isolated species were ascribed only to Arcobacter cryaerophilus. Conclusions: Culturable and nonculturable forms of Arcobacter in the estuarine environment were present. PCR assays were more sensitive than traditional culture in detecting Arcobacter butzleri and A. cryaerophilus. FISH comparatively to PCR technique may provide information about cell morphology and viability of single cells. Significance and Impact of the Study: Our investigation indicates the existence of an environmental reservoir of potential pathogenic arcobacters in an estuarine Italian area, which may survive under a viable but not culturable state.