Mahima Lall1, A K Sahni2. 1. Classified Specialist (Pathology & Microbiology), Dept of Pathology & Molecular Medicine, Army Hospital (R&R), Delhi Cantt 110010, India. 2. Professor & HOD, Department of Microbiology, Armed Forces Medical College, Pune 40, India.
Abstract
BACKGROUND: Therapy for Staphylococcal infections may be complicated by the possibility of inducible macrolide-lincosamide-streptogramin B resistance (MLSBi). We studied the prevalence of MLSBi in community associated (CA) and hospital associated (HA) Staphylococcus aureus isolates from clinical samples. METHODS: A total of 305 strains of S. aureus comprising 140 (45.9%) [95% CI 40.36-51.52] methicillin resistant S. aureus (MRSA) and 165 (54%) [95% CI 48.48-59.64] methicillin-sensitive S. aureus (MSSA) were identified by conventional methods. The double disc test (D test) was applied by placing erythromycin and clindamycin discs to investigate inducible and constitutive MLSBi resistant phenotypes. RESULTS: 16.6% of MRSA showed constitutive resistance and 37.5% inducible MLSBi resistance. Community associated MRSA (CA-MRSA) represented 10% of all isolates and had lower prevalence of MLSBi than hospital associated MRSA (HA-MRSA). CONCLUSION: Routine screening for inducible MLSBi resistance by double disc test can screen for potential treatment failures such that clindamycin can be used effectively and judiciously when indicated for staphylococcal infections especially for treating skin and soft tissue infections (SSTIs) in CA-MRSA due to low prevalence of MLSBi among CA-MRSA.
BACKGROUND: Therapy for Staphylococcal infections may be complicated by the possibility of inducible macrolide-lincosamide-streptogramin B resistance (MLSBi). We studied the prevalence of MLSBi in community associated (CA) and hospital associated (HA) Staphylococcus aureus isolates from clinical samples. METHODS: A total of 305 strains of S. aureus comprising 140 (45.9%) [95% CI 40.36-51.52] methicillin resistant S. aureus (MRSA) and 165 (54%) [95% CI 48.48-59.64] methicillin-sensitive S. aureus (MSSA) were identified by conventional methods. The double disc test (D test) was applied by placing erythromycin and clindamycin discs to investigate inducible and constitutive MLSBi resistant phenotypes. RESULTS: 16.6% of MRSA showed constitutive resistance and 37.5% inducible MLSBi resistance. Community associated MRSA (CA-MRSA) represented 10% of all isolates and had lower prevalence of MLSBi than hospital associated MRSA (HA-MRSA). CONCLUSION: Routine screening for inducible MLSBi resistance by double disc test can screen for potential treatment failures such that clindamycin can be used effectively and judiciously when indicated for staphylococcal infections especially for treating skin and soft tissue infections (SSTIs) in CA-MRSA due to low prevalence of MLSBi among CA-MRSA.
Entities:
Keywords:
D test; Inducible clindamycin resistance; Staphylococcus aureus
Authors: Ravisekhar Gadepalli; Benu Dhawan; Srujana Mohanty; Arti Kapil; Bimal K Das; Rama Chaudhry Journal: Indian J Med Res Date: 2006-04 Impact factor: 2.375