Foodborne diseases often follow the consumption of contaminated food such as meat from infected animals or carcasses contaminated with pathogenic bacteria such as S. aureus. The majority of these microorganisms result from contamination occurring at the slaughterhouse [1Jevons MP. Celbenin-resistant staphylococci. BMJ 1961; 1: 124-5.[http://dx.doi.org/10.1136/bmj.1.5219.124-a] ], where conventional veterinary inspection cannot detect the presence of these bacteria on apparently healthy looking carcasses [2Brown MH, Gill CO, Hollingsworth J, et al. The role of microbiological testing in systems for assuring the safety of beef. Int J Food Microbiol 2000; 62(1-2): 7-16.[http://dx.doi.org/10.1016/S0168-1605(00)00408-6] [PMID: 11139 024] ].

Meat is not only highly susceptible to spoilage, but also frequently implicated in the spread of foodborne diseases. Contaminated raw meat is one of the main sources of foodborne diseases, whereby all potentially edible tissues are subjected to contamination from a variety of sources [3Bhandare SG, Sherikar AT, Paturkar AM, Waskar VS, Zende RJ. A comparison of microbial contamination on sheep/goat CARCASSES in modern Indian abattoir and traditional meat shops. Food Control 2007; 18: 854-8.[http://dx.doi.org/10.1016/j.foodcont.2006.04.012] ].

S. aureus is a leading cause of food poisoning resulting from the consumption of contaminated food with staphylococcal enterotoxins [4Tassew H, Abdissa A, Beyene G, Gebre-Selassie S. Microbial flora and food borne pathogens on minced meat and their susceptibility to antimicrobial agents. Ethiop J Health Sci 2010; 20(3): 137-43.[PMID: 22434972] ]. Raw meat is a good medium for S. aureus survival and spread of drug-resistant S. aureus in the community [5Chaibenjawong P, Foster SJ. Desiccation tolerance in Staphylococcus aureus . Arch Microbiol 2011; 193(2): 125-35.[http://dx.doi.org/10.1007/s00203-010-0653-x] [PMID: 21088825] ]. The rapid evolution of antibiotic-resistant S. aureus is of considerable concern. Multidrug-resistant S. aureus strains are especially one of the greatest public concerns since the treatment of infections caused by resistant S. aureus is more complicated and difficult [6Ateba C, Mbewe M, Moneoang MS, Bezuidenhout C. Antibiotic resistant Staphylococcus aurous isolated from milk in Mafikeng Area, North West Province, and South Africa. S Afr J Sci 2010; 106: 12-3.[http://dx.doi.org/10.4102/sajs.v106i11/12.243] ]. Methicillin-resistant S. aureus (MRSA) is known to be one of the most prevalent nosocomial pathogens throughout the world and is capable of causing a wide range of hospital-linked infections [7Abdalla MA, Siham E, Sluman YY, Alian HA. Microbial contamination of sheep carcasses at modern slaughter house in Khartum state Sud J Vet Sci Anim Husb 2009; 48(1 and 2): 51-6.].

A limited number of investigations have been conducted on the potential of raw meat to spread drug-resistant S. aureus as a source of infection. The objective of this study is to look for the prevalence of drug-resistant S. aureus in Addis Ababa abattoir enterprise.

The study was carried out in Addis Ababa, from November 2013 to April1 2014 at Ethiopian Public Health Institute (EPHI) food microbiology laboratory. Sample collection was carried out at Addis Ababa abattoir enterprise. Analyses of data were performed using IBM SPSS Statistics V21. We con-sidered p values <0.05 as statistically significant.

The overall prevalence of S. aureus in sheep, goat carcasses and the environmental samples was 33% (61/185). The highest prevalence of S. aureus was found in sheep carcasses (36%) followed by swabs from the environment (knife, workers’ clothes, slaughtering area and transporting vehicles) 30%, and goat carcasses (16.0%). No statistically significant association was found between the sheep and goat carcasses and environmental samples for S. aureus contamination (P > 0.05) (Table 1).

The study has highlighted that MDR S. aureus occurrence in meat and meat origin represents a threat to public health related to food safety. In the last few decades, staphylococcal food poisoning has been reported as the third cause of foodborne illnesses in the world. Meat, milk and dairy products play a vital role in staphylococcal food poisoning [6Ateba C, Mbewe M, Moneoang MS, Bezuidenhout C. Antibiotic resistant Staphylococcus aurous isolated from milk in Mafikeng Area, North West Province, and South Africa. S Afr J Sci 2010; 106: 12-3.[http://dx.doi.org/10.4102/sajs.v106i11/12.243] ].

In the present study, the overall prevalence of S. aureus was found to be 33%. This finding is incomparable with the findings observed in [7Abdalla MA, Siham E, Sluman YY, Alian HA. Microbial contamination of sheep carcasses at modern slaughter house in Khartum state Sud J Vet Sci Anim Husb 2009; 48(1 and 2): 51-6.] Sudan 16%, 12% [1Jevons MP. Celbenin-resistant staphylococci. BMJ 1961; 1: 124-5.[http://dx.doi.org/10.1136/bmj.1.5219.124-a] ] and 32.5 in South Africa from cattle and pig carcasses [9Scott E, Bloomfield SF. The survival and transfer of microbial contamination via cloths, hands and utensils. J Appl Bacteriol 1990; 68(3): 271-8.[http://dx.doi.org/10.1111/j.1365-2672.1990.tb02574.x] [PMID: 211 1304] ]. There was no significant difference in bacterial isolates among sheep carcasses, goat carcasses and environment swabs at P>0.05. This could be due to the similarity of the hygienic practices between them. In this study all S. aureus isolates were tested for twelve antibacterial agents which showed 86.9%, 80.3%, 63.9%, 62.3%, 62.3%, 57%, 42.6%, 39.3%, 3.3%, 1.6% resistance to penicillin G, ampicillin, ceftriaxone, oxacillin, cefoxitin clindamycin, nalidixic acid, erythromycin, gentamicin, kanamycin and chloramphenicol (Table 4).

Table 3
Drug resistance pattern of S.aureus from meat and environmental samples.

Fig. (1) Percent resistant for S. aureus isolates from carcasses and environments (n=61) for different antibiotics.

Table 4
A summary of multiple drug resistant S.aureus isolates.

In the present study, 21 (34.4%) S. aureus strain showed multidrug resistance whereby the most common one was resistance primarily to ampicilin, ceftriaxone, clindamycin, cefoxitin. This could be due to the inappropriate use and misuse of β-lactam and other antibiotics as a means of treatment and thereby the development of resistance. The finding is lower in MDR resistance with the finding of [10Abebe M, Daniel A, Yimtubezinash W, Genene T. Identification and antimicrobial susceptibility of S. aureus isolated from sheep carcass, goat carcass and isolated from milk samples of dairy cows and nasal swabs of farm workers in selected dairy farms around Addis Ababa, Ethiopia. Afr J Microbiol Res 2013; 7(27): 3501-10.] who reported 45% of S. aureus strains had resistance to three and more of the tested antimicrobials and much lower than the study done by 90% in Jimma [11Fish D, Piscitelli S, Danziger L. A review of antibiotic classes and patient characteristics in 173 studies, pharmacy therapy 1995; 15: 279-91.]. Based on the result of this study vancomycin, chloramphenicol, gentamicin, and kanamycin were effective against S. aureus and this is in agreement with the findings of other investigators [1Jevons MP. Celbenin-resistant staphylococci. BMJ 1961; 1: 124-5.[http://dx.doi.org/10.1136/bmj.1.5219.124-a] ].

The microbial population and dynamics of foodborne pathogens (S. aureus, Salmonella, Escherichia coli, and others) that comes in contact with fresh meat during slaughtering, dressing and processing present a challenging problem to the meat industry. The condition of the animals prior to slaughter, sanitary condition of the slaughtering environment, and slaughtering materials also contribute to S. aureus carriage of meat and butchers. The occurrence of S. aureus in raw meat is of high importance where raw meat is eaten as a cultural food. Moreover, the presence of 75.4% MDR strain demonstrates the fast-growing strain of S. aureus which will become a threat to the public. Thus, it requires strong and strict implementation of GMP up to the food handlers.