Prevalence and antimicrobial resistance profiles of Salmonella enterica serovars isolated from slaughtered cattle in Bahir Dar, Ethiopia

Abstract

A study was undertaken from October 2006 to March 2007 to determine the prevalence and antimicrobial resistance patterns of Salmonella serovars. Liver, mesenteric lymph nodes, intestinal content, and carcass swab samples (each n = 186) were collected from 186 apparently healthy slaughtered cattle at Bahir Dar abattoir. Bacteriological analysis was done according to the International Organization for Standardization (ISO 6579 2002). Isolates were serotyped at Agence Française de Securite Sanitaire des Aliments, Cedex, France. Twenty-eight isolates consisting of Salmonella Typhimurium, Salmonella Newport, Salmonella Haifa, Salmonella Heidelberg, Salmonella Infantis, and Salmonella Mishmarhaemek were identified. Salmonella Typhimurium and Salmonella Newport were most frequently isolated while Salmonella Heidelberg and Salmonella Mishmarhaemek were isolated least. Eleven of the 28 (39.3%) were resistant to one or more of the antimicrobials tested. Resistance was shown to ampicillin, chloramphenicol, gentamycin, norfloxacin, polymyxin-B, streptomycin, tetracycline, and trimethoprim. Four of 11 (36.4%) were multiple antimicrobial resistant. All the isolates tested were susceptible to the antimicrobial effects of gentamycin, norfloxacin, and trimethoprim. Eleven, four, and two isolates of the 28 were resistant to streptomycin, tetracycline, and ampicillin, respectively. All isolates of Salmonella Infantis, Salmonella Typhimurium (except one), and Salmonella Mishmarhaemek were susceptible to the tested antimicrobials. One Typhimurium isolate was resistant to chloramphenicol, streptomycin, and tetracycline. Salmonella Haifa was multiply antimicrobial resistant to ampicillin, tetracycline, and streptomycin. All isolates of Salmonella Heidelberg were resistant to streptomycin. Results of this study indicated high level of carcass contamination with antimicrobial-resistant Salmonella serovars which could pose public health risk; suggests need for hygienic slaughtering operations and proper cooking of meat before consumption. Further detailed studies involving different abattoirs, animal products, food items, and animals on different settings were recommended in the study area.

Salmonella serovars along two beef chains in Ethiopia

“…The prevalence in beef at the abattoir level (11.8%) was similar with the 9.8% rate reported by Nyeleti et al [1], higher than the 2.8% and 3.1% rates [8], 2% [3] from carcass swabs at a beef abattoir, and lower than 42.8% (n = 236) reported from Senegal [21]. It was similar to the rates of 11.9% and 9.8% found in the diaphragm and abdominal muscles, respectively [1].…”

“…The 23.5% result from animal feces was similar to the 19% found in rumen contents reported by Sibhat et al [3], and higher than 2.2% in cattle feces [1], 3.1% in pooled feces [8], and 15.1% in camel feces [9].…”

“…The overall prevalence of 12.9% in this study was lower than that reported by Molla et al [10], with 23.6% from food animals in Ethiopia, and similar to a study reporting 7.1% positive samples out of 323 cattle in Debre Zeit [8].…”

“…Kagambega et al [4] reported Salmonella data in cattle from Burkina Faso, and Adabara et al [5] from hospital cases in Nigeria. Salmonella reports are available in Ethiopia on the prevalence of Salmonella in different food animals, such as cattle, sheep, goats and pigs [1,2,[6][7][8], camels [9], chickens [10] at abattoirs, from animal products at supermarkets [1,2,11], and from human cases [12,13]. Serotypes reported from Ethiopia include 48% each for S. Dublin and S. Mishmarhaemek, 20% for S. Typhimurium [8], 54% for S. Anatum, 19% for S. Newport [3], 38.8% for S. Saintpaul, and 22.4% for S. Braenderup [9].…”

“…Braenderup, and S. Muenchen were also frequently isolated from animal and food of animal origin in abattoirs and supermarkets [1][2][3][8][9][10][11][14][15]. S. Concord was obtained from hospital case samples [16].…”