Evaluation of methicillin resistance in Staphylococcus intermedius isolated from dogs

Area of Science:

• Veterinary Microbiology
• Antimicrobial Resistance
• Canine Infectious Diseases

Background:

• Staphylococcus intermedius is a common canine pathogen.
• Methicillin resistance in bacteria is a growing global health concern.
• Understanding resistance patterns in veterinary settings is essential for effective treatment.

Purpose of the Study:

• To investigate the prevalence of methicillin resistance in Staphylococcus intermedius strains from dogs.
• To determine the association between methicillin resistance and multi-drug resistance in these strains.
• To evaluate the accuracy of diagnostic methods for methicillin resistance.

Main Methods:

• Polymerase chain reaction (PCR) to detect the mecA gene.
• Phenotypic antimicrobial susceptibility testing (AST) using disk diffusion and complementary tests.
• Analysis of 136 Staphylococcus intermedius isolates of canine origin.

Main Results:

• Only four out of 136 strains were mecA-positive, indicating a low prevalence of methicillin-resistant Staphylococcus intermedius (MRSI).
• MRSI strains showed significantly higher resistance to fusidic acid, lincosamides, and cotrimoxazole compared to methicillin-susceptible strains.
• Oxacillin disk diffusion yielded one false-negative result, highlighting potential diagnostic limitations.

Conclusions:

• Methicillin resistance in canine S. intermedius is associated with multi-drug resistance.
• Antimicrobial susceptibility testing is vital for guiding treatment decisions in canine S. intermedius infections.
• The study underscores the importance of monitoring antimicrobial resistance in veterinary pathogens.