Molecular characterisation of carbapenemases in urban pigeon droppings in France and Algeria.

OBJECTIVES: The main objective of this study was to detect the presence of carbapenemase-encoding genes in stool samples of urban pigeons.

METHODS: Stool samples were collected from 73 pigeons in two Mediterranean cities, namely Marseille (France) and Annaba (Algeria). Faecal samples were screened by real-time PCR and standard PCR for the presence of carbapenemase-encoding genes.

RESULTS: Carbapenem resistance genes were detected in 16 (21.9%) of the samples, with 8 positive for blaOXA-23, 12 positive for blaOXA-51-like and 13 positive for blaOXA-58. No samples were positive for blaNDM-1, blaOXA-24, blaOXA-48, blaVIM or blaKPC. All positive samples were screened for the presence of Acinetobacter spp. by partial rpoB gene sequence amplification, and the results showed the presence of five Acinetobacter spp., with percentage similarities to related species in GenBank ranging between 96% and 100%. The dominant species was Acinetobacter guillouiae, followed by Acinetobacter baumannii, Acinetobacter haemolyticus, Acinetobacter pittii and Acinetobacter nosocomialis. One DNA sequence showed a very low degree of homology (92%) with Acinetobacter gerneri, suggesting a new Acinetobacter spp.

CONCLUSIONS: Here we report the first detection of carbapenemase-encoding genes from urban pigeon stools. These results question the potential of birds as a reservoir for the spread of these resistance determinants both in animals and humans.