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Updated: Aug 2, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Isolation and Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) from Milk in Shire Dairy Farms,
Weldemelak Girmay1, Getachew Gugsa2, Habtamu Taddele1
1College of Veterinary Sciences, Mekelle University, Mekelle, Ethiopia.
Abstract:
Antibiotic-resistant Staphylococcus aureus isolates pose a severe challenge to both veterinary and health professions and dairy cattle producers. Cross-sectional study was conducted from November 2014 to May 2015 to isolate and identify S. aureus from mastitic cows' milk and estimate the occurrence of MRSA in the dairy farms of Shire. Physical examination and California mastitis test were performed on a total of 220 dairy cows. Bacteriological isolation and identification and antibiogram testing were performed. Furthermore, multiplex polymerase chain reaction (PCR) was done for the detection of mec A and fem A genes. Out of the 220 dairy cows, 64 (29.09%) were positive for bovine mastitis, and of these, 32.81% were coagulase-positive S. aureus (CoPS). Antibiogram test results showed 100% of the isolates were resistant to penicillin G, nalidixic acid, and ampicillin, and 33.33% of the CoPS showed resistance to oxacillin (phenotypically MRSA positive). But 38.09% of the CoPS were found to be resistant and susceptible to vancomycin. PCR amplification of the seven phenotypically MRSA isolates revealed that 42.9% and 71.4% of them were found to carry fem A and mec A genes, respectively. The current study revealed the existence of alarming level of CoPS and development of multidrug resistance.
Insights
Antibiotic-resistant Staphylococcus aureus strains are a significant threat in dairy herds. This study found high rates of resistance and multidrug-resistant S. aureus in Shire dairy farms, indicating an alarming situation.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Resistance
- Food Safety
Background:
- Antibiotic-resistant *Staphylococcus aureus* presents a major challenge in veterinary medicine and dairy production.
- Controlling *S. aureus* in dairy cattle is crucial for animal health and preventing economic losses.
Purpose of the Study:
- To isolate and identify *Staphylococcus aureus* from mastitic cows' milk in Shire.
- To determine the prevalence of Methicillin-Resistant *Staphylococcus aureus* (MRSA) and associated resistance genes.
Main Methods:
- Cross-sectional study involving physical examination and California Mastitis Test on 220 dairy cows.
- Bacteriological isolation, identification, antibiogram testing, and multiplex PCR for *mecA* and *femA* genes.
Main Results:
- Bovine mastitis was detected in 29.09% of cows, with 32.81% of positive cases yielding *S. aureus*.
- 100% of isolates were resistant to penicillin G, nalidixic acid, and ampicillin. 33.33% of *S. aureus* isolates were phenotypically MRSA positive.
- MRSA isolates showed varying resistance to vancomycin (38.09%) and carried *mecA* (71.4%) and *femA* (42.9%) genes.
Conclusions:
- The study highlights an alarming prevalence of *S. aureus* and multidrug resistance in dairy farms in Shire.
- Urgent interventions are needed to control *S. aureus* and combat antimicrobial resistance in dairy cattle.
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