Bacteriological study of community-acquired pyoderma with special reference to methicillin-resistant Staphylococcus aureus

Background: Pyoderma is one of the most frequently encountered condition in dermatology clinics in India. Staphylococcus and Streptococcus are the most common causative agents. There is considerable variation in the reported antibiotic susceptibility pattern of the organisms isolated from pyoderma with a trend toward increasing resistance. Objectives: The objectives of this study were (1) to study the clinical patterns of cutaneous bacterial infections, (2) to determine the antibiotic sensitivity of the isolates obtained, and (3) To assess the prevalence of methicillin resistance (methicillin-resistant Staphylococcus aureus [MRSA]) among the community–acquired (CA) pyoderma. Materials and Methods: Two hundred and fifty-six patients of CA pyoderma constituted the study population. A detailed history was taken and thorough clinical examination was performed. Gram-stained smear examination and culture and sensitivity test of pus were done. Results: Primary pyoderma was seen in 48.8% and secondary pyoderma in 51.2% of cases. The most common primary pyoderma was folliculitis (52%) followed by furuncle (25.6%). In secondary pyoderma, the most common condition was infected eczema (38.2%) followed by infected ulcers (22.1%). Staphylococcus was isolated in 87.5%, Streptococcus in 2%, and mixed organisms were isolated in 5.5% of cases. Maximum susceptibility was seen to tigecycline (89.1%) and linezolid (88.3%). Among topical antibiotics, mupirocin was susceptible in 75.8% and fusidic acid in 66.4% of the organisms. The highest resistance was seen to benzylpenicillin in 81.6% followed by ciprofloxacin in 53.1% of the organisms. The least resistance was seen for daptomycin in 0.8%, tigecycline in 1.6%, linezolid in 2.3%, and mupirocin in 2.7% of the organisms. The proportion of MRSA in CA pyodermas was 25.5%. Conclusion: The study yielded some useful epidemiological and clinicobacteriological data about CA pyoderma. The above observations made regarding antibiotic sensitivities may assist clinicians in choosing antibiotics for CA pyoderma in the absence of pus culture sensitivity