Isolation, Identification and Antimicrobial Susceptibility Test of Mastitis Causing Bacteria at Holeta Agricultural Research Center Dairy Farms

Abstract

A cross-sectional study was conducted from November 2014 to April 2015 to determine the prevalence of bovine mastitis, isolation of mastitis causing bacteria's and characterize antimicrobial susceptibility pattern at Holeta Agricultural Research Centre (HARC) Dairy Farms. Purposive sampling technique was employed and all lactating cows were involved in the study. Among 186 lactating cows consists of 92 Jersey as well as 94 cross breed (Boran X Holistein Fresian) were included in the study. Among selected cows, 131 (70.43%) cows were identified as bovine mastitis positive and out of which 10 (5.37%) had clinical mastitis and 121 (65.05%) had subclinical mastitis. The different types of bacterial species isolated in present study includes S. aureus (30.93%), staphylococcus other than S. aureus (14.43%), Str. agalactiae (5.15%), Str. Dysgalactiae (5.15%), Str. Uberis (12.37%), C. bovis (13.40%), E. coli (6.18%), P. aerogenosa (10.3%) and K. pneumonie (2.05%). Antimicrobial susceptibility testing revealed that 94% and 78.6% of total isolates were susceptible to gentamycin and trimethoprim-sulfamethoxazole, respectively which was followed by erythromycin and tetracycline with susceptibility rate of 73.8% and 69%, respectively. However, penicillin had shown susceptibility of 55.9% which was the least effective among the drugs used. In conclusion, different types of mastitis causing pathogens with variable rate of susceptibility to antimicrobials were able to identify. Therefore, antimicrobial therapy should be used after isolation of the suspected pathogen to avoid emergence of drug resistance.

Bovine Mastitis: Prevalence, Risk Factors, and Bacterial Pathogens Isolated in Lactating Cows in Gamo Zone, Southern Ethiopia

“…The high prevalence of S. aureus (42.6%) in this study is in accordance with the reports of Dereje et al, 11 Kumbe et al, 20 and Mekibib et al, 22 who reported predominance of S. aureus in causing bovine mastitis. High prevalence of S. aureus is related to poor milking hygiene, as this pathogen primarily spreads during milking through milkers’ hands and towels.…”

“…Overall, the quarter-level prevalence of 7.94% recorded in this study was in agreement with a report of 8.03% 17 in West Harerghe, but lower than the 29.4%, 1 45.68%, 5 54.75%, 11 21.48%, 20 29.04%, 21 and 39.4% 36 found in other studies. Compared to other quarters, the right rear showed the highest proportion of infection (9.9%), followed by the left rear (9.7%).…”

“…In this study NAS were the third–most predominantly isolated bacteria, with frequency of 14.8%, in accordance with Dereje et al, 11 and Seid et al, 32 who reported 14.43% and 16.9% in different parts of Ethiopia, but lower than the 30.1%, 34.2, and 26.6%, reported by Mekibib et al, 22 Tesfaye and Abera, 36 and Zeryehun and Abera, 40 respectively. NAS are seen as unimportant pathogens and typically treated as normal inhabitants of the bovine udder.…”

“…Bacteriological analysis of 72 milk samples revealed growth of various groups of bacteria in 64 (88.9%) samples, comparable to Mekibib et al 22 and Yenew and Addis, 39 who reported 90% and 85.7%, respectively, but higher than the 38.5% of Amin et al, 5 66.12% of Dereje et al, 11 46.97% of Kumbe et al, 20 and 31.5% of Zeryehun and Abera. 40 Also, it was lower than Abebe et al 2 who recorded 98.8% growth.…”

“…In settings where hand-milking and unwarranted usage of drugs is exercised to treat mastitis, its dominance has been reported. 11 …”