A cross-sectional study was conducted in Hawassa town and its surroundings from October 2007 to May 2008 to estimate the prevalence of bovine tuberculosis (BTB) based on comparative interadermal tuberculin test (CIDT) and abattoir survey. Accordingly, 39 herds comprising 413 cattle were subjected to CIDT, and the herd and individual animal prevalence were 48.7% (19/39) and 11.6% (48/413), respectively. One of the 16 milk samples collected from tuberculin-positive cows was culture positive. The prevalence significantly differed among the age group (P = 0.001) and management system (P = 0.001). Thus, age group over four (OR = 7.9) and animal with poor management system (OR = 4.1) had a higher odds for tuberculin reactivity compared to those with age group under four and cattle with good management system, respectively. Of the total 1,023 cattle subjected to postmortem examination, 11 (1.1%) were found to be positive for gross tuberculous lesions. Larger proportion (50%) of TB lesion was recorded in the respiratory pathway followed by digestive system (28.6%) and prescapular lymph nodes (21.4%). Of 14 tissue specimens collected from the gross lesions, four (28.6%) were positive for histopathological TB lesions. In conclusion, this study revealed the importance of BTB in the study area in particular and the region in general.

A cross sectional study was conducted between January and May 2015 in and around Kombolcha town, Eastern Amhara, to identify methicillin resistant Staphylococcus aureus and their resistance to antimicrobials and also to identify risk factors associated with the occurrence of dairy cow mastitis. A total of 150 dairy cows were included during the study period. A total of 600 quarters were examined to detect clinical and subclinical mastitis by physical examinations of udder and milk and California mastitis test, respectively. The prevalence of mastitis was 56%. Age, milking hygiene, parity, and floor system had significant (p<0.05) effect on the prevalence of mastitis. S. aureus was isolated at a rate of 11 (73.3%) and 29 (42%) in clinical and subclinical mastitis, respectively. The result showed the occurrence of S. aureus in clinical mastitis was found to be significantly higher than subclinical mastitis (p=0.028). The present study showed that S. aureus was resistant to penicillin G (100%), amoxicillin (100%), cefoxitin (42.7%) and tetracycline (77.4%) however all the isolates were found to be totally (100%) susceptible to the gentamycin. 45.3% of the isolates were found to be multidrug resistant. Antimicrobial resistance is due to repeated therapeutic use of drugs. Regular antimicrobial sensitivity testing helps to select effective antibiotics that ultimately reduce the development of resistance towards commonly used antibiotics. In conclusion, Mastitis caused by S. aureus is one of the major problems of dairy cows in milk production in the study area.

SUMMARYOne hundred and five shigella isolates from Addis Ababa were studied to determine serogroup frequency and in vitro antibacterial drug sensitivity.About 70 % of the isolates were Shigella flexneri followed by Sh. dy8enteriae (15%), Sh. boydii (10%) and Sh. sonnei (5 %). All or most of the strains were susceptible to cephalothin, gentamicin, kanamycin, polymyxin B and trimethoprimsulphamethoxazole. Frequencies of susceptibility to ampicillin, carbenicillin and chloramphenicol were, respectively, 79, 80 and 75 %. Only 37, 23 and 58 % were susceptible to streptomycin, sulphadiazine and tetracycline, respectively.Resistance to one or more drugs was detected in 85 % while 72 % were multiply resistant. There were 24 different resistance patterns, varying from resistance to one drug to resistance to seven drugs.The findings have been compared with reports from other countries. This study and several others cited support the view that trimethoprim-sulphamethoxazole is the best alternative drug for treatment of shigellosis particularly in regions with multiple drug-resistant strains.

A cross -sectional study was conducted from November 2016 to May 2017 in Dairy cattle in and around Asossa town in order to estimate the prevalence of mastitis, to identify S. aurues from mastitic lactating cows, to evaluate its antimicrobial resistance pattern and to identify risk factors associated with mastitis. A total of 384 Dairy cows milk samples were collected using purposive sampling techniques. The overall prevalence of mastitis at cow level was 39.32% with 11.45% and 27.86% of clinical and subclinical mastitis, respectively. In this study, the subclinical mastitis was significantly higher than clinical mastitis. For all except Age and parity, the multivariable logistic regression analysis for intrinsic and extrinsic risk factors showed significant difference in the prevalence of mastitis in the study area (P˂0.05). From 151 mastitis infected lactating cows, 436 milk samples were cultured and 22.14% S. aureus were isolated. Presumptively identified S. aureus isolates were subjected to antimicrobial susceptibility test and 63 (74.11%) MRSA have been identified from a total of 85 S. aureus using cefoxitin through disk diffusion method. The present result showed a significant association of resistance pattern with S. aureus isolates, particularly to penicillin G (95.55%), Cefoxitin (77.19%), Tetracycline (63.41%), Streptomycin (60.78%), Gentamycin (59.37%), Vancomycin (56.75%), Clindamycine (54.35%) and Bacitracin (53.65%). In this study, 77.19% S. aureus isolates were found resistant against Cefoxitin. There were also observed multidrug resistance, mainly to Penicillin G, Streptomycin and Tetracycline. The present study revealed higher prevalence of mastitis and occurrence of multidrug resistance S. aureus specifically which belongs to the MRSA which are dependent on multiple associated risk factors. Hence, regular resistance follow-up, using antimicrobials sensitivity tests helps to select effective antimicrobials and to reduce the problems of drug resistance developments towards commonly used antimicrobials.

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