Composition of enterococcal and streptococcal flora from pigeon intestines

To identify the streptococcal and enterococcal components of the microflora from pigeon intestines to species level by tDNA-intergenic polymerase chain reaction.

Gram-positive coccal strains were isolated from the intestines or faeces of 50 different pigeons, all from different lofts, on Columbia CNA blood agar. Sodium azide-sensitive enterococci were found to constitute the major coccal members of the intestinal flora of pigeons. Forty-two of 69 isolates were identified as Enterococcus columbae (84% of animals tested positive), while E. cecorum was encountered in 28% of all animals (14 isolates). Minor species (less than 10% of pigeons positive) were E. faecalis, E. faecium, E. gallinarum, E. casseliflavus, Streptococcus alactolyticus and Strep. gallolyticus. Contrary to the species description of E. columbae and E. cecorum, some of the strains were found to be motile. Certain other minor differences with the species description of E. columbae are also indicated.

Enterococcus columbae is the major Gram-positive facultatively anaerobic component of the pigeon intestinal flora. Certain phenotypic characteristics differ from the original species description. The potentially pathogenic Strep. gallolyticus is a minor component of the microflora. Enterococcus faecium and E. faecalis are rare in pigeons.

The enterococcal and streptococcal flora of pigeons is composed of mainly host-specific bacteria. These are not likely to act as zoonotic pathogens nor as carriers of antibiotic resistance determinants possibly spreading to humans.