Staphylococcus aureus is actually a normal inhabitant of the skin of humans and a number of companion animal and livestock species. These staphylococci are usually harmless. However, they can cause wound or skin infections, among other things, in people and animals with a poorly functioning immune system. Such conditions can easily be treated with antibiotics. If the infection is caused by methicillin-resistant Staphylococcus aureus (MRSA), though, wound-healing disorders that are difficult to treat can develop.
MRSA in horses
Excessive and incorrect use of antibiotics in human and veterinary medicine promotes the development of resistance and thus also the presence of MRSA. MRSA was first described in equine medicine in the 1990s and is becoming increasingly common. It is problematic especially in the context of wound infections – in surgical wounds for example – and because of the resulting impairment of wound healing. MRSA germs can be transmitted from humans to horses and vice versa. It is vital to interrupt this chain of transmission, and it is therefore important to wash and disinfect hands and wear disposable gloves when treating wounds in horses. Wounds must always be cleaned and disinfected thoroughly. Dead and infected tissue should be removed.
Antibiotics are not always necessary
Antibiotics are rarely required to treat superficial wounds. The correct and conservative use of antibiotics in human and veterinary medicine can reduce the development of further resistance. It is probably not possible to eliminate MRSA. These germs are very common in humans and animals worldwide, but their spread can be countered by targeted hygiene and prevention measures in veterinary and human medicine.
Research and surveillance
The problem of MRSA and other resistant germs has been a focus of active research for years at the Swiss Institute of Equine Medicine ISME (Equine Clinic in Bern and Avenches) and at the equine clinic of the Vetsuisse Faculty in Zurich. Antibiotic resistance is being studied in various diseases, both in hospitalised animals and outside in stabled animals. One example of the diseases concerned is mallanders, a relatively common, painful bacterial skin infection that affects horses’ legs.
MRSA has been monitored in pigs and calves for slaughter since 2009 in Switzerland. A big increase in the prevalence of MRSA has been observed in pigs for slaughter since monitoring began, while calves for slaughter are far less commonly affected. The Swiss Antibiotic Resistance Report 2020 provides more information about this topic and about the detection of MRSA on fresh meat.
Sources: Resistente Keime auch für Pferde eine Gefahr [“Resistant germs a danger for horses too”], Pferdewelt, 2020; Swiss Antibiotic Resistance Report 2020.
