Occurrence and antibiotic susceptibility of Helicobacter pullorum from broiler chickens and commercial laying hens in Italy

In 2005, in order to investigate the occurrence of Helicobacter pullorum in poultry, the caecal contents collected from a total of 60 animals intensively reared in Italy on 15 different farms (9 farms of broiler chicken and 6 of laying hens) were examined at the slaughterhouse. A modified Steele-McDermott membrane filter method was used. Small, greyish-white colonies of Gram-negative, gently curved, slender rod bacteria were preliminarily identified as H. pullorum by a Polymerase Chain Reaction (PCR) assay based on 16S rRNA and were then subjected to an ApaLI digestion assay to distinguish H. pullorum from Helicobacter canadensis. One isolate from each farm was phenotypically characterized by biochemical methods and 1 D SDS-PAGE analysis of whole cell proteins; antibiotic susceptibility was also tested. According to the PCR and PCR-RFLP results, all the animals examined were positive for H. pullorum. The 1 D SDS-PAGE whole protein profile analysis showed high similarity among the 15 isolates tested. A monomodal distribution for the Minimum Inhibitory Concentrations (MICs) was found for ampicillin, chloramphenicol, gentamicin and tetracycline. For erythromycin and ciprofloxacin, a bimodal trend having a second peak at > 128 mu g ml(-1) and 32 mu g ml(-1) was found. The isolation method used in this study seems to be highly suitable for isolating H. pullorum from chicken caecal contents. Moreover, the detection of a high number of colonies phenotypically similar to H. pullorum suggests that this microorganism, when present, colonizes the caecum at high concentration. (c) 2007 Elsevier B.V. All rights reserved.