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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Inducible clindamycin and methicillin resistant Staphylococcus aureus in a tertiary care hospital, Kathmandu, Nepal
R P Adhikari1, S Shrestha2, A Barakoti2
1Department of Microbiology, Nepal Medical College and Teaching Hospital, Jorpati, Kathmandu, Nepal. rampd11@yahoo.com.
Background:
Staphylococcus aureus, an important nosocomial pathogen, is frequently associated with infections in human. The management of the infections by it especially methicillin resistant ones is often difficult because methicillin resistant S. aureus is usually resistant to multiple antibiotics. Macrolide-lincosamide streptogramin B family of antibiotics is commonly used to treat such infections as an alternative to vancomycin.
Methods:
This study was conducted over the period of one and half year from November 2013-April 2015 in Microbiology laboratory of Nepal Medical College and Teaching Hospital, Kathmandu, Nepal to find the incidence of different phenotypes of MLSB resistance among S. aureus from clinical samples and their association with methicillin resistance. Two hundred seventy isolates of S. aureus were included in the study. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by erythromycin and clindamycin disc approximation test (D-test).
Results:
Of the 270 clinical isolates of S. aureus, 25.1% (68/270) were MRSA. Erythromycin and clindamycin resistance was seen in 54.4% (147/270) and 41.8% (113/270) isolates respectively. Resistance to erythromycin and clindamycin were higher in MRSA as compared to MSSA (erythromycin-resistance: 88.2% Vs 39.1% and clindamycin-resistance: 79.4% Vs 41.8%). The overall prevalence of iMLSB and cMLSB phenotype was 11.48% (31/270) and 29.25% (79/270) respectively. Both iMLSB and cMLSB phenotypes predominated in MRSA strains.
Conclusions:
Detection rate of MRSA in our study shows the necessity to improve in healthcare practices and to formulate new policy for the control of MRSA infections. Clindamycin resistance in the form of iMLSB and cMLSB especially among MRSA emphasizes the need of D-test to be performed routinely in our set up while using clindamycin as an alternative choice to anti-staphylococcal antibiotics like vancomycin and linezolid in the treatment of staphylococcal infections.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen. This study found high rates of clindamycin resistance in MRSA, highlighting the importance of the D-test for guiding treatment decisions.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Staphylococcus aureus is a major cause of hospital-acquired infections.
- Methicillin-resistant S. aureus (MRSA) presents treatment challenges due to multidrug resistance.
- Macrolide-lincosamide streptogramin B (MLSB) antibiotics are alternatives to vancomycin for MRSA infections.
Purpose of the Study:
- To determine the incidence of MLSB resistance phenotypes in S. aureus clinical isolates.
- To investigate the association between MLSB resistance and methicillin resistance.
- To assess the prevalence of inducible (iMLSB) and constitutive (cMLSB) resistance.
Main Methods:
- A total of 270 S. aureus isolates were analyzed from clinical samples.
- Methicillin resistance was identified using the cefoxitin disc diffusion method.
- Inducible clindamycin resistance was detected using the erythromycin and clindamycin disc approximation test (D-test).
Main Results:
- 25.1% of S. aureus isolates were identified as MRSA.
- Erythromycin and clindamycin resistance rates were 54.4% and 41.8%, respectively.
- MRSA isolates exhibited significantly higher resistance to erythromycin and clindamycin compared to methicillin-susceptible S. aureus (MSSA).
- The prevalence of iMLSB and cMLSB phenotypes was 11.48% and 29.25%, respectively, with both predominantly found in MRSA strains.
Conclusions:
- The high detection rate of MRSA underscores the need for improved healthcare practices and MRSA control policies.
- The prevalence of iMLSB and cMLSB phenotypes in MRSA necessitates routine D-testing when considering clindamycin as an alternative antibiotic.
- Effective management of staphylococcal infections requires careful consideration of antibiotic resistance patterns.
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