Isolation, antimicrobial susceptibility patterns, and risk factors assessment of non-typhoidal Salmonella from apparently healthy and diarrheic dogs.

BACKGROUND: Dogs are one of the important asymptomatic carriers of antimicrobial resistant and potentially pathogenic strains of Salmonella. They can harbor large bacterial load in the intestines and mesenteric lymph nodes which can be shed in their feces with the possibility of transmission to humans. Therefore, a cross-sectional study was conducted with the objectives of estimating the prevalence of non-typhoidal Salmonella, assessing the risk factors for dog's Salmonella carriage, and profiling the antimicrobial resistance pattern of Salmonella isolates among housed dogs in Harar town, Eastern Ethiopia. A total of 415 rectal swab samples were collected from randomly selected dogs. Samples were examined for non-typhoidal Salmonella using standard bacteriologic culture and biochemical tests. The disk diffusion method (Kirby-Bauer test) was employed to evaluate the isolates for their susceptibility against five antimicrobials. RESULTS: Non-typhoidal Salmonella were isolated from 26 (6.3%) of the rectal swab samples, with significantly higher occurrence in diarrheic (15.2%) than non-diarrheic (5.5%) dogs. The risk of Salmonella harboring was significantly higher in female dogs than in male dogs (OR = 2.5, p = 0.027). Dogs fecal shedding of Salmonella was relatively higher in households who used offal as a main feed type for their dogs (23.1%; 95% CI = 5-53.8) than those who used leftover food (10.1%; 95% CI = 5.7-16.1) and practiced mixed feeding system (17%; 95% CI = 7.6-30.8). Salmonella isolates showed higher resistance to ampicillin (41.7%), while all isolates were fully susceptible to gentamicin. Moreover, 58.3% of Salmonella isolates showed resistance to at least one of the tested antimicrobials. Majorities (72.7%) of the dog owners had no awareness on the risk of zoonotic salmonellosis from dog and all of the respondents use bare hand to clean dog kennel. CONCLUSION: Our study reveals the importance of both diarrheic and apparently healthy housed dogs in the harboring and shedding of antimicrobial resistant non-typhoidal Salmonella. The risk of non-typhoidal Salmonella spread among pet owners is not negligible, especially in households who use offal as main feed type. Therefore, an integrated approach such as: proper dog handling practices; continuous evaluation of antimicrobial resistance; and rational use of antimicrobials in the field of veterinary sector are necessary to tackle the problem.

Determination of Tetracycline Residues in Kidney and Muscle of Beef Cattle Slaughtered in Dire Dawa and Harar Municipal Abattoirs, Eastern Ethiopia.

Background: Antibiotics are among the most widely used drugs in farm animals for therapeutic and prophylactic purposes. However, the antibiotic residues in meat are a serious public health concern due to their harmful effects on consumer health. Besides this problem, there is limited information on the level of the antibiotic residues, including tetracycline residues. Therefore, this study was aimed to determine the tetracycline residues in the kidney and muscle samples of beef cattle in Harar town and Dire Dawa city. Methods: A study was conducted on 500 randomly selected carcass (250 kidney and 250 muscle samples) slaughtered at Dire Dawa and Harar municipal slaughterhouses between December 2018 and December 2019. The samples were collected aseptically and screened for tetracycline residues by thin layer chromatography. Then, presumptive positive samples were analyzed using high-performance liquid chromatography to get a quantitative outcome. Descriptive statistics were used to determine the frequency, mean, or standard deviation to determine the summary values and distribution of the outcomes. Finally, the data was analyzed using SPSS version 21 software. Results: Out of 500 samples, oxytetracycline residues were detected in 84% of the samples. However, tetracycline and doxycycline were not detected in all samples. Among the kidney and muscle samples collected from Dire Dawa and Harar abattoirs, 109 (87.2%) and 101 (80.8%) were positive for oxytetracycline, respectively. Oxytetracycline residue levels in Dire Dawa ranged from 57 to 607 µg/kg for the kidney and 10.14 to 435 µg/kg for muscle samples. Among the samples collected from Harar, the concentration of oxytetracycline residues ranged from 16 to 433 µg/kg and 6 to 435 µg/kg for kidney and muscle samples, respectively, at Harar slaughterhouses. About 22.0% of muscle samples collected from Dire Dawa and 17.8% from Harar town had oxytetracycline residues above maximum residue limits. Conclusions: In general, the study revealed that oxytetracycline residues were prevalent among tetracycline residues analyzed from kidney and muscle samples in the study areas. Thus, there is a risk of consumer exposure to these antibiotic residues that may have human health effects. Therefore, awareness creation and strict regulation is needed by the regulatory authorities for the use of antimicrobial drugs in the livestock industry.