Microbiological Characterization of Two Surfaces of Veterinarians’ Stethoscopes in Trujillo, Peru

The stethoscope is a medical instrument used daily for physical examinations, whose capacity as a fomite remains underexplored in veterinary medicine. The objective of this study is to identify the main bacteria isolated from the stethoscopes of veterinarians in Trujillo (Peru) and to identify the factors associated with the presence of these pathogens through microbiological analysis and the application of a questionnaire. Fifty-nine stethoscopes were sampled using sterile swabs soaked in BHI broth (Brain Heart Infusion) and rubbed 4 times, at different locations in opposite directions to the previous one. The surfaces sampled were: chest pieces and ear tips. After being incubated for 24 hours at 37°C, they were cultured in Agar blood and after identification of the bacterial morphology, biochemical tests were performed. Results showed that 88% of stethoscopes were contaminated, yielding 100 isolates (8 genera). Staphylococcus aureus (35%) was the most frequently isolated species, followed by Coagulase-negative Staphylococcus (34%) and Pseudomonas spp. (18%). Notably, high levels of antimicrobial resistance were observed, with S. aureus exhibiting 94.3% resistance to penicillin and 80% to tetracycline. The chest piece was the most contaminated surface (95%; 56/59). A statistical association was found between disinfection practices and bacterial presence (p<0.05), with non-disinfection identified as a risk factor (OR=1.636; 95% CI=1.132-2.366). The above shows that veterinary stethoscopes, often contaminated with bacteria linked to nosocomial infections, require effective disinfection protocols and robust antimicrobial stewardship programs to mitigate the spread of multidrug-resistant bacteria, protect patient and user health, and preserve antibiotic efficacy in the long term.