[Determining the prevalence of Salmonella serotypes obtained from meat and chicken samples and their antibiotic resistance pattern in Tehran]

ABSTRACT

Food borne diseases are still the major problem in both industrial and nonindustrial countries and the prevalence of these diseases are on rise. Consuming of contaminated meats with Salmonella is the major source for distributing these diseases. Adding antibiotics in domestic animals' food causes antibiotic resistance so the resistant bacterium could be transfer to the human through the consumption of such foods. The aim of this study was to determine the Salmonella serotypes, and antibiotic resistance of isolated serotypes obtained from packed and non- packed meat and chicken purchased in different districts of Tehran, during 2004 and 2005. In this cross-sectional study, samples were taken randomly from 10 packaged meat suppliers and 17 non-packaged meat suppliers. Out of 133 prepared samples, 67 ones were chicken and 66 samples were meat. Samples were weighted, separated [each 25gr] and put into 225ml of Buffered Peptone Water. Then homogenized by Stomacher and incubated at 37[o]c for 24 hours. After that 0.1 ml of solution poured into 10 ml of Rappaport Vassilidis broth and remained 24 hours in 42[o]c. Then, one loop of this medium was cultured on Hektoen Entro Agar and remained for a period of 24 hours in 37[o]c to enter Salmonella colonies. For the antibiotic sensitivity test, the agar disc diffusion was used according to the standard method. Out of 67 tested samples of chicken, 32 samples [47.8%] were contaminated with Salmonella, as well as 19 meat samples [28.8%] [from the total 66 ones]. The dominated serotype of both chicken and meat samples was S.thompson [54.6%]. The results of antibiotic susceptibility showed that 90.6% of isolated chicken samples were resistant to Nalidixic acid, compared to 36.8% of meat samples. According to the observed antibiotic resistance in some of tested samples, special attention in quality control of food's safety in order to prevent the related diseases is needed