Browsing by Author "Reagan Muhwezi"

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    Molecular characterisation and associated factors of methicillin-resistant Staphylococcus aureus isolated from milkmen and cows associated with Sub-clinical mastitis in Kiruhura district, Uganda
    (Kampala International University, 2023-04-13) Reagan Muhwezi
    Background: Subclinical mastitis (SCM) is caused by Methicillin-resistant Staphylococcus aureus among other causative agents, a superbug that poses a threat to the worldwide dairy industry and is notably blamed for the substantial financial losses documented on dairy farms in Uganda. The present study aimed at isolating and genotyping methicillin-resistant Staphylococcus aureus from milkmen and cows with subclinical mastitis in Kiruhura district, Uganda. Methods: A cross-sectional study was conducted in Kiruhura district, western Uganda. Two hundred raw milk and 100 nasal samples (from milkmen) collected from 100 randomly selected dairy farms were analysed to obtain quantitative data. Qualitative data was obtained through farm observations and farmer interviews using formal questionnaires. Preliminary detection of Subclinical mastitis in cows was done using the California mastitis test (CMT). Standard culture and isolation of S. aureus from both milk and nasal swab samples were done. The antibiotic susceptibility pattern of the isolates was determined using the Kirby Bauer disc diffusion method. In addition, a conventional polymerisation chain reaction was performed on phenotypically identified S. aureus isolates to detect both spa and mecA genes of the methicillin resistant strains of S. aureus isolates. Results: Out of 200 cows sampled, 88.5% (95% CI; 0.8350-0.9239) were positive for CMT. 6.0% of cows had S. aureus infections, of which 4/12 (33.3%) had the MecA gene. Additionally, 9% of milkmen had nasal S. aureus, and 55.0% (5/9) were methicillin-resistant. The risk factors for the high prevalence of S. aureus infections among SCM infected dairy cows were included; milkmen with at most secondary level of education (aOR= 16.484, 95% CI= 1.739-156.262, p= 0.015), milkmen with nasal S. aureus (aOR= 13.722, 95% CI= 1.987-94.751, p= 0.008) and MRSA (OR= 16.312, 95% CI= 2.367.112.404, p= 0.005), and unhygienic milking places (p= 0.047). The occurrence of MRSA in SCM-infected cows was significantly associated with nasal MRSA (cOR= 62.667, 95% CI= 4.377-897.239, p= 0.002). All S. aureus isolates were extremely resistant to penicillin G, tetracycline, cefoxitin, and oxacillin while they were highly susceptible to gentamicin Conclusion: Bidirectional transmission of S. aureus and MRSA between milkmen and dairy cows was the major risk factor for SCM on studied dairy farms. There is a need to improve farm management and hygienic practices, in addition to routine laboratory checkups for SCM in dairy cows and nasal S. aureus in milkmen.