Epsilon Archive for Student Projects

Abstract

Antibiotic resistance is a pressing global health issue exacerbated by the global misuse of antibiotics across human, animal, and environmental interfaces. Antibiotic resistance is the phenomenon in which bacteria are no longer affected by the presence of antibacterial drugs. Resistant
genes can occur naturally, as mutations in the bacterial genome or via acquired genes from other
bacteria. Resistant bacteria can be transmitted between humans, animals and the environment via
food, direct contact or waste. With increased antibiotic resistance, life-threatening diseases
become more difficult to treat, leading to greater suffering and premature death.
In Kenya, the use of antibiotics is mostly unregulated and access to veterinary diagnostics is
often limited. In a previous study, a high prevalence of antibiotic-resistant E. coli in domestic cats
in Mararienta, Kenya, was discovered. Milk from livestock is a common food source for humans
and cats in the region, making it a potential source of transmission of resistant bacteria.
This study investigated the prevalence of antibiotic-resistant Escherichia coli and Staphylococcus aureus in milk from goats and sheep within Mararienta, as well as in milk collection containers and feeding bowls for domestic cats. The method of choice for detecting antimicrobial
resistance was disk diffusion, and the antibiotics used in this study were cefoxitin, tigecycline,
gentamicin, ciprofloxacin, meropenem and benzylpenicillin. These antibiotics were chosen to be
able to compare results to earlier studies done in the region and for their individual importance in
human and veterinary therapy. A One Health perspective was employed, considering the close
relations between humans, animals, and the environment in the region.
In total, 130 sheep and goats from 12 households were tested for subclinical mastitis using the
California Mastitis Test (CMT), since only animals with subclinical mastitis were of interest.
Milk samples (n=28) and swabs from milk containers (n=5) and feeding bowls (n=5) were analyzed for bacterial growth and antibiotic susceptibility. Despite occurrence of mixed bacterial flora
in milk containers and feeding bowls, no antibiotic-resistant E. coli or S. aureus were isolated
from milk samples or swabs. Only one E. coli strain was identified in a feeding bowl but was
susceptible to all tested antibiotics.
The low prevalence of subclinical mastitis and minimal bacterial growth in milk samples
suggest that milk is an unlikely source of antibiotic resistance transmitted to the domestic cats.
However, it was noted that carcasses from livestock treated with antibiotics were often fed to cats
and dogs. The unregulated use of antibiotics and lack of knowledge for the withdrawal period of
antibiotics were therefore identified as potential risks for the spread of antibacterial resistance.