Tropical Veterinary Medicine

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Browsing Tropical Veterinary Medicine by Subject "Antimicrobials"

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    SALMONELLA SEROVARS IN APPARENTLY HEALTHY SLAUGHTERED CATTLE AT BAHIR DAR ABATTOIR, ETHIOPIA
    (2007-06) SEFINEW, ALEMU; Dr. Bayleyegn Molla
    The present cross-sectional study was undertaken to determine the prevalence, distribution and antimicrobial resistance patterns of Salmonella serovars from apparently healthy slaughtered cattle from October, 2006 to March, 2007 at Bahir Dar abattoir, Ethiopia. A total of 744 samples consisting of liver, mesenteric lymph nodes, intestinal content and carcass swab (each n = 186) were collected from 186 slaughtered cattle. Bacteriological analysis for Salmonella was done following the recommendations of the International Organization for Standardization (ISO 6579, 2002). Serotyping of the Salmonella isolates was done at Agence Française de Securite Sanitaire des Aliments (AFSSA), Cedex, France. Salmonella was isolated in one or more of liver, mesenteric lymph nodes, and intestinal content from 13 (7%) of the slaughtered cattle. Of the 744 samples analyzed, 28 (3.8%) were positive for Salmonella. There was difference in the prevalence of Salmonella among liver, mesenteric lymph nodes, intestinal content and carcass swab samples; difference in prevalence was not statistically significant (Fisher's exact = 0.06, P > 0.05). The highest prevalence 5.9% (11 of 186) was detected from intestinal content while the lowest prevalence 1.1% (2 of 186) was detected from liver. The prevalence of Salmonella in mesenteric lymph nodes was 3.2% (6 of 186). Of the total 186 examined animals, carcass contamination was observed in 4.8% (9 of 186) of them. However, there was no statistical association between the prevalence of carcass contamination and the prevalence of any of the other samples. Six different serovars consisting of Salmonella Typhimurium, S. Newport, S. Haifa, S. Heidelberg, S. Infantis and S. Mishmarhaemek were identified among the 28 isolates. Salmonella Typhimurium and S. Newport were the most frequently isolated serovars each contributing 21.4% (6 of 28) of the total isolates while Salmonella Heidelberg and S. Mishmarhaemek were the least frequently isolated, each with a prevalence of 7.1% (2 of 28). Antimicrobial resistance test was done for all the 28 isolates against eight antimicrobials by disk diffusion technique based on the guidelines of National Committee for Clinical Laboratory Standards (NCCLS, 1997). Among the 28 isolated Salmonella 39.3% (11 of 28) were resistant to one or more of the tested antimicrobials, of which 63.6% (7 of 11) were resistant to a single antimicrobial while the rest 36.4% (4 of 11) were resistant to two or more of the antimicrobials (multiple antimicrobial resistant). All of the isolates were sensitive to the viii antimicrobial effects of gentamycin, norfloxacin, and trimethoprim. Eleven of 28 (39.3%) of the isolates were resistant to streptomycin followed by tetracycline and ampicillin with prevalence of 14.3% (4 of 28) and 7.1% (2 of 28) respectively. The identified serovars had different antimicrobial resistance patterns. In Salmonella Haifa 66.7% of them were multiple antimicrobial resistant to streptomycin, ampicillin and tetracycline while the rest 33.3% were resistant only to streptomycin. All isolates of Salmonella Typhimurium were susceptible to the tested antimicrobials except one isolate which was resistant to chloramphenicol, streptomycin and tetracycline. Salmonella Haifa was multiple antimicrobial resistant to ampicillin, tetracycline and streptomycin. Salmonella Mishmarhaemek and S. Infantis were susceptible to all of the tested antimicrobials while all serovars of S. Heidelberg were resistant to streptomycin. In conclusion, there is possibility of the public to be at risk due to high level of carcass contamination with the single and/or multiple antimicrobial resistant Salmonella serovars observed in this study. Therefore, hygienic slaughtering in the abattoir and proper cooking of meat at household level should be practiced. The consumer should be aware of the risk of consumption of raw or undercooked meat under the meat shed of Bahir Dar abattoir.