Resistance pattern of community-acquired S. aureus infections in children

Abstract number: 1733_1318

Panagea T., Ikonomopoulos G., Makri A., Vatopoulos A., Koukou P., Voyatzi A.

Introduction: Community-acquired (CA) methicillin-resistant S. aureus (MRSA) infections in healthy children and young adults are a recent worldwide phenomenon. Most CA-MRSA strains are producing Panton Valentine Leukocidin (PVL), a highly potent toxin, associated with skin lesions, soft tissue infections and necrotising pneumoniae.

Objectives: The purpose was to determine the incidence, the antibiotic resistance pattern and the prevalence of PVL producing S. aureus isolates in children suffering from skin or soft tissue infections in the community.

Material and Methods: A total of 285 strains S. aureus were isolated from 960 samples obtained from children aged 0–14 years old, during the last 2 years (October 2004–October 2006). All children suffered from skin or soft tissue infections and attended the outpatient department for medical advice. Samples were obtained from skin lesions (520), abscesses (290), wounds (120), and umbilical swabs (30).

Identification of S. aureus was achieved by conventional methods. Antibiotic susceptibility testing was performed according to the CLSI guidelines. Twenty randomly selected CA-MRSA strains were further examined by PCR technique for the presence of lukF-PV and lukS-PV genes.

Results:S. aureus was responsible for 29.7% of community acquired skin and soft tissue infections in children. Antibiotics resistance pattern was as follow: penicillin 91%, methicillin 22.9%, fusidic acid 19%, tetracycline 23.6%, clindamycin 2.3%, gentamicin 0.9%, erythromycin 13.1%, rifampicin 0.9%, trimethoprim-sulfamethoxazole 0.9%, chloramphenicol 1.2% and ciprofloxacin 0.9%. None of the strains was resistant to vancomycin, teicoplanin and amikacin. MRSA accounted for 22.9% of all CA-S. aureus infections. Out of 65 MRSA strains, 48 (73.8%) were also resistant to fusidic acid and tetracycline. The genes lukF-PV and lukS-PV were detected in 18 out of 20 (90%) CA-MRSA strains.

Conclusion: In our paediatric population, 22.9% CA-MRSA infections were observed. Ninety percent of examined CA-MRSA isolates were found to be PVL producers. A significant number of MRSA isolates (73.8%) were resistant to fusidic acid and tetracycline. This unusual antibiotic resistance pattern has been associated with the presence of PVL producing ST80 CA-MRSA clone, that has previously been described in Greece.