Related Experiment Video
Updated: Jul 29, 2025
Author Spotlight: Exploring Photodynamic Therapy with Curcumin in a Murine Model for Oral Candidiasis
Published on: October 27, 2023
Comparative Susceptibility of Pathogenic Methicillin-Resistant and Methicillin-Susceptible Staphylococcus
Usasom Khongsri1,2, Peerawit Chongrattanameteekul1, Sineenart Chantarachart2
1Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
Abstract:
The prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) that causes pyoderma has been gradually shifting, according to many surveillance studies, with annual changes. The empirical cotrimazole regimen remains interesting, but research on cotrimazole susceptibility to MRSP is limited. The objective of this study was to evaluate the susceptibility of cotrimazole to canine pyoderma MRSP isolates. Sixty isolates of S. pseudintermedius were identified as 16 MRSP and 44 methicillin-susceptible S. pseudintermedius (MSSP) using an oxacillin disk diffusion test and VITEK 2 system with VITEK GP card. Using the VITEK 2 system with a VITEK AST-GP81 card, the susceptibility rates of MRSP (15.00%) and MSSP (35.00%) to cotrimazole was observed. The median MIC of cotrimazole on MSSP (median, ≤10; IQR, 10-320) was lower than that of MRSP (median, ≥320; IQR, 10-320) (p = 0.5889, Mann-Whitney test). Percent attainment of PK/PD targets in MRSP (q 12 h, 43.75; q 8 h, 43.75) were lower than that of MSSP (q 12 h, 52.27; q 8 h, 52.27) (p = 0.7710). These findings show the moderately phenotypic cotrimazole susceptibilities of both MRSP and MSSP. Further study is required to develop clinical trials examining the use of cotrimazole in dogs with pyoderma.
Insights
This study assessed cotrimazole susceptibility in canine pyoderma isolates, finding moderate susceptibility in both methicillin-resistant Staphylococcus pseudintermedius (MRSP) and methicillin-susceptible S. pseudintermedius (MSSP). Further clinical trials are needed to explore cotrimazole
Area of Science:
- Veterinary Dermatology
- Antimicrobial Susceptibility Testing
- Canine Infectious Diseases
Background:
- Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an increasing cause of canine pyoderma.
- Limited data exists on the susceptibility of MRSP to cotrimazole, a potential treatment.
- Understanding cotrimazole efficacy against MRSP and MSSP is crucial for effective pyoderma management.
Purpose of the Study:
- To evaluate the in vitro susceptibility of canine pyoderma isolates to cotrimazole.
- To compare cotrimazole susceptibility between MRSP and methicillin-susceptible S. pseudintermedius (MSSP) isolates.
Main Methods:
- Sixty canine S. pseudintermedius isolates were identified as MRSP (n=16) or MSSP (n=44).
- Oxacillin disk diffusion and VITEK 2 system were used for isolate identification.
- Cotrimazole susceptibility was determined using the VITEK 2 system with a VITEK AST-GP81 card.
Main Results:
- Susceptibility rates to cotrimazole were 15.00% for MRSP and 35.00% for MSSP.
- Median Minimum Inhibitory Concentration (MIC) of cotrimazole was higher for MRSP (≥320) than MSSP (≤10).
- Pharmacokinetic/pharmacodynamic (PK/PD) target attainment was lower in MRSP (43.75%) compared to MSSP (52.27%).
Conclusions:
- Canine pyoderma MRSP and MSSP isolates exhibit moderately phenotypic cotrimazole susceptibilities.
- The observed susceptibility rates suggest potential limitations for empirical cotrimazole use.
- Further clinical trials are warranted to investigate the therapeutic efficacy of cotrimazole in canine pyoderma.
