Characterization of Staphylococcus aureus isolated from poultry meat in Spain

Ninety-six Staphylococcus aureus isolates from retail chicken carcasses in Spain were characterized using cultural and biochemical tests. The strains were phage typed with the international bacteriophage set for typing S. aureus of human origin. Eighty-eight (91.7%) strains were of the poultry ecovar. Strains of human ecovar were not found. These facts are congruent with findings of other authors. Ninety (93.7%) strains were phage typeable. Lysis by phages of Group III was the most frequent with 66 (68.7%) sensitive strains. Twenty-eight (29.2%) strains were sensitive at 100 routine test dilution (RTD) and only 16 (167%) at RTD. By using reversed phage typing, we managed to increase the number of phage typeable strains by 46 (47.9%). More than one S. aureus phage type was detected in 14 (35%) carcasses, which emphasizes the convenience of subtyping several S. aureus isolates from the same food sample in epidemiological studies. Two phage patterns (75/84 and 6/1030/W57) were the most common. The S. aureus isolates were closely related, as 78 strains showed the most common or indistinguishable (<2 phage reaction differences) phage patterns.