A cross-Sectional Study on Salmonella in Apparently Healthy Slaughtered Sheep and Goats at Addis Bbaba and Modjo Abattoirs, Ethiopia
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2004-06
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Addis Ababauniversity
Abstract
The present study was undertaken on apparently healthy slaughtered sheep and goats, and apparently healthy abattoir personnel at Addis Ababa public and Modjo modern export abattoirs from September, 2003 to February, 2004. The objectives of the study were to determine the prevalence and distribution of Salmonella in sheep and goats and abattoir personnel, to identify and characterize the prevalent Salmonella serotypes and to determine the antimicrobial resistance of Salmonella isolates to selected antimicrobial agents. A total of 1224 samples consisting of faeces (n=204), mesenteric lymph nodes (n=204), liver (n=204), spleen (n=204), abdominal (n=204) and diaphragmatic muscles (n=204) samples from 104 sheep and 100 goats and 117 stool samples from abattoir personnel were collected. The samples were examined for the presence of Salmonella following the techniques recommended by the International Organization for Standardization (ISO 6579, 1998). Salmonellae were isolated from 12 of 104 (11.5% (95% CI = 6.1-19.3)) sheep and 3 of 100 (3% (95% CI = 0.6-8.5)) goats and none of the samples from abattoir personnel were positive for Salmonella. The frequency of isolation and distribution of Salmonella in different tissue and faecal samples of sheep and goats was analyzed. Of the total 624 samples examined from apparently healthy slaughtered sheep, 18 (2.9%) were Salmonella positive. Salmonellae were isolated from 4.8% faecal, 7.7% mesenteric lymph nodes, 1.9% liver and 1.9% abdominal muscle samples. Only one isolate was found from spleen and Salmonella was not detected from diaphragmatic muscle samples. Four (0.7%) Salmonella positive samples were detected from a total of 600 samples from apparently healthy slaughtered goats. Salmonella was isolated from 2% faecal and 2% mesenteric lymph nodes samples whereas in other organs Salmonella was not detected. In both species, the number of positive specimens was higher for faeces and mesenteric lymph nodes samples than others.
Serotypes and phage types of Salmonella strains isolated from sheep and goats were identified. All the 22 Salmonella isolates were serotyped and serotypes of S. Typhimurium, S. Heidelberg, S. Typhimurium var. Copenhagen and S. Enteritidis strains were further phage typed. A total of 9 different serotypes were identified from sheep (n=7) and goats (n=3), of which S. Typhimurium (36.4%) and S. Heidelberg (18.2%) were the most prevalent serotype followed by S. Give, S. Poona and S. Reading (each 9.1%). Other serotypes including S. Typhimurium var. Copenhagen, S. Enteritidis, S. Niederoderwitz and S. I: 6, 7, 14:-: enz15 were also detected from sheep and goats. The most common serotypes recovered in sheep
were S. Typhimurium (38.9%) and S. Heidelberg (22.2%) and in goats it was S. Poona (50.0%). Three serotypes, S. Poona, S. I: 6, 7, 14:-:enz15 and S. Niededrowtiz were reported for the first time in Ethiopia. The phage types identified include S. Typhimurium phage type 46, S. Typhimurium phage type 193, S. Typhimurium phage type 2, S. Typhimurium phage type 79, S. Typhimurium phage type U285, S. Typhimurium var. Copenhagen phage type 104, S. Enteritidis phage type 5a and S. Heidelberg phage type atypical. Of which S. Heidelberg phage type atypical was the most common phage type in sheep. Salmonella Typhimurium phage type 46 was the most prevalent phage type of S. Typimurium phage types in sheep whereas S. Typhimurium phage type 193 was found both in sheep and goats. All isolates were tested for susceptibility to a group of 24 selected antimicrobials. Out of the 22 isolates tested, 7 (31.8%) were multiple resistant from two to up to nine antimicrobials. Among the isolates, only S. Typhimurium (62.5%) and S. Reading (100%) displayed multiple resistances to ten different antimicrobials. Salmonella Typhimurium isolates were resistant to ampicillin and cephalothin (each 50.0%), sulfisoxazole, streptomycin, sulfamethoxazol-trimethoprim and trimethoprim (each 25.0%), amoxicillin/clavulanic acid, chloramphenicol, spectinomycin and tetracycline (each 12.5%). However, S. Reading isolates showed resistance only to streptomycin, sulfisoxazole and tetracycline (each 100%). The results of this study showed the potential risk of sheep and goats as sources of pathogenic and multi-drug resistant Salmonella serotypes for humans in the study area. This is a significant threat to public health particularly to those who have direct or indirect contact to sheep and goats and consumers who have the habit of eating sheep and goats meat or meat products either raw or under cooked. These findings stressed the need for implementation of Salmonella control and prevention strategies from farm production to consumption of animal and animal products.
Key words: Sheep, goats, abattoir personnel, Salmonella, serotypes, prevalence, antimicrobial resistance, Addis Ababa, Modjo
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Keywords
Sheep, goats, abattoir personnel, Salmonella, serotypes, prevalence, antimicrobial resistance, Addis Ababa, Modjo