Isolation, serologic identification and antibiotic sensitivity testing of Salmonella spp. in poultry

This study aimed to isolate and identify the serotypes and determine the antibiotic sensitivity patterns of Salmonella isolates from 325 poultry samples. Poultry meats, eggs and cloacal swabs were sampled to isolate Salmonella by conventional method and serotype them using specific typing sera. Antibiotic sensitivity test was carried out by the Kirby-Bauer method. The total Salmonella recovery rate was 4.92% (16/325), 9.3% (14/150) of which were isolated from meat samples and 2% (2/100) from cloacal swab samples. Salmonella was not detected in egg samples. There was no significant difference (p-value = 0.40) between the number of Salmonella isolates from the Calamba and Los Banos public markets. Among the meat types, the breast and wing had greater number of isolates (10%) compared to the thigh (8%), but the difference was not significant (p-value=1). Only 4% of the cloacal swab samples were positive of Salmonella. Seven serotypes belo nging to serogroups B, C2, C3, D1 and E1 were isolated in this study. These are S. weltevreden, S. derby, S. newport, S. albany, S. lexington, S. enteritidis PT1, and S. enteritidis phage type untypable. S. weltevreden was the predominant serotype followed by S. derby then S. newport. This is the first time that S. albany is isolated in poultry in the country. Most of isolates were highly sensitive to norfloxacin (100%), gentamicin (100%), cephalothin (100%), ampicillin (97%), and trimethoprim-sulfamethoxazole (97%). Resistance was found in nitrofurantoin (100%), tetracycline (16.3%), ampicillin (3%), and trimethoprim-sulfamethoxazole (3%). One hundred percent of the serotypes were resistant to at least one antibiotic, 9.7% showed multi-drug resistance to nitrofurantoin, tetracycline and trimethoprim-sulfamethoxazole. This study revealed that Salmonella continues to contaminate our food with new serotypes present including S. enteritidis PT1. The antibiotic sensitivity patte r ns of the serotypes have changed and showed that serotypes were resistant to antibiotics, particularly nitrofurantoin. It is therefore recommended that proper food handling practices be emphasized repeatedly and that antibiotics be prudently used in food animals.