Methicillin resistant Staphylococcus aureus (MRSA) infection in cystic fibrosis

Background-Methicillin resistant Staphylococcus aureus (MRSA) infection is increasingly found in patients with cystic fibrosis (CF). Aims-To determine whether MRSA infection has a deleterious effect on the cl inical status of children with CF. Methods-Children with MRSA in respiratory cultures during a seven year peri od were identified and compared with controls matched for age, sex, and res piratory function. Respiratory function tests, anthropometric data, Shwachm an-Kulczycki score, Northern chest x ray score, intravenous and nebulised a ntibiotic therapy, and steroid therapy were compared one year before and on e year after MRSA infection. Results-From a clinic population of 300, 10 children had positive sputum or cough swab cultures for MRSA. Prevalence rose from 0 in 1992-1994 to 7 in 1998. Eighteen controls were identified. Children with MRSA showed signific ant worsening of height standard deviation scores and required twice as man y courses of intravenous antibiotics as controls after one year. They had s ignificantly worse chest x ray scores at the time of the first MRSA isolate and one year later, but showed no increase in the rate of decline in chest x ray appearance. There was a trend towards lower FEV1 and FEF25-75 in chi ldren with MRSA. There were no significant differences between the two grou ps with respect to change in weight, body mass index, or Shwachman score. T here was no significant difference in prior use of steroids or nebulised an tibiotics. Conclusion-MRSA infection in children with CF does not significantly affect respiratory function, but may have an adverse effect on growth. Children w ith MRSA require significantly more courses of intravenous antibiotics and have a worse chest x ray appearance than controls.