Drawbacks of the use of cotrimoxazole in foreign-body infections

Area of Science:

• Microbiology
• Infectious Diseases
• Pharmacology

Background:

• Cotrimoxazole efficacy is potentially reduced in difficult infections with high thymidine levels.
• Foreign-body infections often involve significant pus and devitalized tissue, leading to high thymidine concentrations.

Purpose of the Study:

• To evaluate cotrimoxazole activity against Staphylococcus aureus in an experimental foreign-body infection model.
• To assess the impact of high thymidine levels on cotrimoxazole's anti-staphylococcal efficacy.

Main Methods:

• Utilized a rat tissue-cage model of infection with methicillin-susceptible Staphylococcus aureus (MSSA).
• Determined Minimum Inhibitory Concentration (MIC) values using a microdilution method.
• Compared MICs in the presence and absence of tissue-cage fluid containing high thymidine levels.

Main Results:

• Cotrimoxazole demonstrated inefficacy in the foreign-body infection model, similar to the control group.
• The MIC of cotrimoxazole was 4-8 fold higher when tested in the presence of rat tissue-cage fluid.

Conclusions:

• Cotrimoxazole's inefficacy in this MSSA foreign-body infection model highlights the negative impact of thymidine.
• The findings challenge the use of cotrimoxazole during the acute phase of foreign-body infections.
• Cotrimoxazole should be considered an alternative treatment option once the infection is better controlled.