Prevalence and antimicrobial resistance of animal Salmonellosis in Ethiopia

Background Salmonellosis remained the global public health problems of animals and humans. Consumption of animal food from infected animals or from the contamination of carcasses such as cattle, swine, and sheep and poultry are the main sources of non-Typhoidal Salmonella and the leading cause of zoonotic foodborne diseases. The eligibility criteria of this study has included publication in English, cross-sectional study, samples of food animal origin, antimicrobial sensitivity test methods. Google Scholar and PubMed have used to search the prevalence, incidence, distribution, antimicrobial resistance, animals and humans. Author, study area, study period, sample sources, number of animals, number of samples, positive isolates were used as search strategy. Results A total of 8.4% (564/6721) animal salmonellosis were identified from 11 studies in Ethiopia. The source of samples were pigs, cattle, poultry, and eggs. Five studies were selected for the analysis of prevalence and drug resistance of animal salmonellosis whereas six were found eligible for analysis of animal salmonellosis in serotype level and twenty nine serotypes were extracted having 354 isolates. Of the total 147(6.1%) isolates in five studies, ampicillin, streptomycin and tetracycline were resistant to 89 (60.5%), 70 (47.6%) and 64(43.5%) respectively. The resistant profile for ceftriaxone, gentamicin and ciprofloxacin were 20 (13.6%), 21 (12.9%) and 10 (6.8%), respectively. Twelve serotypes having 204 isolates have showed antimicrobial resistance. Six serotypes had multidrug resistance comprising 120 isolates. The predominant serotype that showed MDR (to three antibiotics) was S. Hadar 81 (67.5%) followed by S. Kentucky 22(18.3%). Conclusion

source of samples for the assessment of the prevalence of animal salmonellosis in Ethiopia were pigs, cattle, poultry, and eggs. Of the total 147(6.1%) isolates in five studies, ampicillin, streptomycin and tetracycline were resistant to 89 (60.5%), 70 (47.6%) and 64(43.5%), respectively. A total of 29 serotypes comprising 354 isolates were revealed from six studies. Twelve serotypes having 204 isolates were showed antimicrobial resistance. Six serotypes showed multidrug resistance and the predominant serotype that showed MDR was S. Hadar 81 (67.5%) followed by S. Kentucky 22 (18.3%) Background Overview of Salmonellosis presence of Salmonellae in water, food, and environment is elucidated by fecal contamination (1).
More than 2500 serotypes/serovars of Salmonellae has been reported (2) and of which 1500 subspecies are associated with human and animal diseases (3) although there is a variation in nature and rigidity among different animals and affected by age, dose, strain virulence, host species, immune status of the host and geographic regions (4). The most clinically important species of Salmonellae is Salmonella enterica subspecies enterica (2). Salmonella enterica subspecies enterica serotype Typhi and para Typhi are highly adapted to human and causes Typhoid fever and para Typhoid fever (5) whereas there are serotypes of Salmonella that adapted animals such as S.
Choleraesuis in pigs, S. Dublin in cattle, S. Abortusovis in sheep and S. Gallinarum in poultry; however, some serotypes like S. Typhimurium affect human and a wide range of animals (6).
Consumption of raw/undercooked meat, raw/undercooked eggs and not cleaning chopping board when using it for raw meat and other foods are the contributing factors for the transmission of human Salmonellosis (7).
Nontyphoidal Salmonella cause bacteremia in the globe particularly in Africa and the annual burden is estimated to be 3.4 million (8) even though the majority of human NTS infection in developed countries are associated with enterocolitis and this is believed to arise through the food chain (9).
Non-Typhoidal Salmonella is the leading cause of zoonotic foodborne diseases that are linked with the consumption of infected animals used in food production or from contamination of the carcasses (10) such as cattle, swine, and sheep (11). Animals are the main reservoirs of human Salmonellosis (12,13) though vegetable foods contaminated by animal products and human excreta have been implicated as the automobile of human salmonellosis (14). Salmonellae in the infected animals' mesenteric lymph nodes and feces can contribute as a source for the contamination of red meat and other edible parts of the carcasses (14,15) and also by the contaminated abattoir equipment and utensils (15,16).
The public health problem of Salmonella is not only by its infection but also by its drug resistance and economic impacts (17). The highest number of illnesses, hospitalizations, and deaths associated with foodborne illness are due to non-Typhoidal Salmonella (18). About 100,000 infections are associated with drug-resistant Salmonella such as annual infections due to ceftriaxone and ciprofloxacin in the United States of America, are 36,000 and 33,000 respectively (17).
A total 624 and 600 samples examined from sheep and goats in Ethiopia and 18 (2.9%) and 4 (0.7%) were Salmonella positive (29), respectively and of the 156 chicken eggs examined in another study in Ethiopia, 24 (15.4%) for eggshells and 13 (8.3%) for yolks were found positive for Salmonellosis (30).
Two (1.3%) of the 150 carcasses were found contaminated with Salmonella species in Ethiopia (31). Serotypes and Antimicrobial Resistance of animal Salmonellosis 5 The most common serotypes identified in Vietnam were S. Agona, S. Emek, and S. London. The identification rates of S. Enteritidis and S. Typhimurium were few (15). The predominant serotypes revealed in a study carried out in South Korea were Salmonella enterica Panama (beef), and Salmonella London and Salmonella Montevideo (chicken meat and pork). All of the isolates of Salmonella species were showed resistance to erythromycin whereas 22.2% for streptomycin and 16.7% for tetracycline and chloramphenicol (24). Five Serotypes of Salmonella including S. Thompson, S. Typhimurium, S. Newport, and S. Hadar were isolated from the chicken meat in Iran. High antimicrobial resistance rates were observed to nalidixic acid (92.8%), tetracycline (81%), streptomycin (56.7%), and kanamycin (36.9%) (16). Eight Salmonella serovars were identified in

Eligible and exclusion studies
A total of 222 published articles were searched. Of these, 205 articles were excluded after reviewing their abstracts. The remaining 17 articles have assessed their full text and 3 were excluded due to failure to include antimicrobial susceptibility testing (31)(32)(33).

Salmonella Serotype and their antimicrobial resistance in animals
Six studies were included to assess the antimicrobial resistance of serotypes of animal salmonellosis.
In each of the eligible studies, top isolates of 12 serotypes comprising 204 isolates were selected to check their resistance status. Accordingly, of the 47 serovars of S. Hadar, 97.9% were resistant to streptomycin and tetracycline (37). Two (22.2%) of the nine tested S. Typhimurium showed resistance to ampicillin, ciprofloxacin, chloramphenicol, streptomycin, and tetracycline (37) and similarly, one of the six (16.7%) tested S. Typhimurium was found resistant to chloramphenicol, streptomycin, and tetracycline (39). In another study, three S. Typhimurium was tested and all of them were resistant to streptomycin and one (33.3%) to tetracycline (41) although no resistance was observed for the seven, tested S, Typhimurium in a study carried out by Eguale (44).
All of the isolates (n = 5) of S. Kentucky showed resistance for ampicillin and ciprofloxacin but 80% (n = 4) for streptomycin and tetracycline (37). Similarly, five isolates of S. Kentucky in a study carried out by Eguale (41) and two isolates of S. Kentucky in another study by Eguale (44) were tested and all of them were resistance for ampicillin, gentamycin, ciprofloxacin, streptomycin and tetracycline, Table 4.

Discussion
Salmonellosis is one of the public health problems of humans and animals in both developed and developing countries (34). Animals are the main reservoirs of human Salmonellosis (12, 13) though vegetable foods contaminated by animal products and human excreta have been implicated as the automobile of human salmonellosis (14). Consumption of animal food from infected animals or from the contamination of carcasses (10) such as cattle, swine, and sheep (11) are the main sources of non-Typhoidal Salmonella and the leading cause of zoonotic foodborne diseases.
In this review, 6721 samples (cattle, pig, poultry, and eggs) were collected from 11 eligible studies to assess the prevalence of animal Salmonellosis in Ethiopia. A total of 564 Salmonella species were identified and 8.4% was found to be a pooled prevalence of salmonella species in animals in Ethiopia.
Hence, there were studies in the same country which showed lower (29, 31, 39, 41, 44 and 46) and higher (30,31,33,(36)(37)(38) prevalence with a range of 1.3% (29) to 23.7% (28). This was also in line with studies carried out in Nigeria (28), Burkinafaso (47) and Italy (48)  S. Typhimurium and S. Enteritidis are stated as the common NTS serotypes in Sub Saharan Africa that are associated with invasive infection in humans (57)(58)(59). The presence of such salmonella prevalence in cattle, poultry, pigs and other animal sources possibly considered as a potential sources of contamination in humans and may the main risk factors for the Salmonella outbreaks in humans (60,61).
In spite of the fact that ceftriaxone (cephalosporin) and ciprofloxacin (quinolones) has not been used for the treatment of animal salmonellosis in Ethiopia. However; ceftriaxone resistance species of salmonella has reported in two studies in Ethiopia (42,46) although the serotype level ceftriaxone resistance report was not found. Similarly, ciprofloxacin resistance of Salmonella was reported in species (42,43) and serotype level in Ethiopia (36, 37, 41, and 44  ceftriaxone 20 (13.6%) (Fig. 2).
Twelve serotypes having 204 isolates were found eligible to assess the antimicrobial resistance. Six serotypes showed multidrug resistance comprising 120 isolates. The predominant serotype that showed MDR (to three antibiotics) was S. Hadar 81 (67.5%) followed by S. Kentucky 22(18.3%).

Eligibility Criteria
The eligibility criteria of this study included publication in English, cross-sectional study, samples of food animal origin, microbial isolation, identification, and antimicrobial sensitivity test methods, and the number of tested isolates and antimicrobial susceptibility testing.

Literature search strategies
Articles related to animals, human salmonellosis were searched in Google Scholar and PubMed. The terms used to search the articles were prevalence, epidemiology, incidence, Salmonella, distribution, antimicrobial resistance, animals, humans, and food. The search covered published articles up to Availability of data and material: All the data used to write this manuscript are available on hand and I can share up on call.

Competing interests:
The author declare that I have no competing interests.

Authors' contributions
AGK was involved in data collection, analysis, drafting the review manuscript and critically reviewing the manuscript. Pooled drug-resistant profile of animal salmonellosis