Search

Similar to the epidemiology of methicillin-sensitive Staphylococcus aureus, community-associated methicillin-resistant S. aureus infections occur in children in different regions of the USA and throughout the world. Although minor skin and soft-tissue infections predominate, life-threatening invasive disease and death can result. The novel genetic elements, staphylococcal cassette chromosome mec IV and V, explain the narrow antibiotic resistance pattern, and suggest the mechanism of spread among staphylococci. Panton-Valentine leukocidin apparently plays a role in its pathogenesis. Clindamycin therapy is often effective for treatment, but inducible resistance can develop if the isolate exhibits macrolide resistance due to the erm mechanism. Other drugs displaying in vitro activity against community-associated methicillin-resistant S. aureus include trimethoprim-sulfamethoxazole, tetracyclines, quinolones, linezolid and vancomycin. While experience in pediatric patients is limited, daptomycin, ketolides, glycylcyclines, newer glycopeptides and beta-lactamase-stable cephalosporins may be useful in the future. Further research could include well-designed studies of mechanisms of virulence, continued surveillance of changes in pathogenicity and susceptibility, as well as treatment effectiveness.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) with a narrower antibiotic resistance pattern have emerged. There is a risk for the appearance of resistance during clindamycin therapy of erythromycin-resistant MRSA infections because of the linked resistance mechanisms., Methods: We analyzed clindamycin-susceptible MRSA organisms from children (1987 to 2000) along with clinical data. Antibiotic susceptibilities of organisms were tested, pulsed field gel electrophoresis (PFGE) was done and the linked resistance mechanism was detected by the D test., Results: An average of 11 clindamycin-susceptible MRSA per year were obtained from children since 1993. Of 88 isolates 33 (38%) were erythromycin-resistant. The latter were less often community-acquired (45% vs. 69%), more often from infants <1 month of age (24% vs. 4%) and less likely to be in the community acquisition-associated PFGE Group 1 (62% vs. 87%) than those that were susceptible. The D test was positive in 31 of 33 erythromycin-resistant isolates. A 9-month-old boy with pneumonia/empyema caused by a clindamycin-susceptible, erythromycin-resistant, D test-positive MRSA developed a PFGE-identical clindamycin-resistant isolate and clinical relapse during clindamycin treatment. In contrast a 12-year-old girl with abscesses caused by a similar MRSA developed another abscess after clindamycin therapy, but the organism was unchanged in susceptibility., Conclusions: Erythromycin resistance was present in 38% of clindamycin-susceptible MRSA in children, and clindamycin resistance was detected during treatment in one child. Clindamycin remains a treatment option if the clinician is notified of the risk by the microbiology laboratory and the clinical situation is suitable.

Background: Recognition of children with community-acquired (CA) infections caused by clindamycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) prompted a retrospective study in two Chicago hospitals conducted from 1987 through 1997., Methods: Laboratory records of MRSA isolates, antibiotic susceptibilities and information from patient medical records were reviewed., Results: One hundred eleven MRSA isolates from 103 children were studied with 51 isolates CA and 77 susceptible to clindamycin. The CA infections were less frequently associated with prior surgery (P = 0.0039) or a foreign body (P = 0.0001), and clindamycin-susceptible MRSA infections were less frequently associated with a foreign body (P = 0.001) compared with nosocomially acquired or clindamycin-resistant MRSA infections. Clindamycin-susceptible MRSA sources were mostly skin, wound or abscess (69%). Soft tissue diagnoses predominated (70%), but 16% were serious invasive infections. Ninety percent of clindamycin-susceptible MRSA were susceptible to erythromycin and/or trimethoprim-sulfamethoxazole. Antibiotic undertreatment (45%) or overtreatment (17%) of children with the clindamycin-susceptible MRSA occurred, but clindamycin appeared to be effective when used., Conclusion: The impact of these organisms could be substantial if they become more frequent or widespread. S. aureus is a potential pathogen in large numbers of pediatric patients; microbiologic evaluation and both presumptive and definitive treatment of all these children may need to be changed.