Detection of MRSA in cystic fibrosis patients associated with shorter survival

Patients with cystic fibrosis (CF) who have Methicillin-resistant Staphylococcus aureus (MRSA) detected in their respiratory tract have worse survival compared to CF patients without MRSA, according to a study in the June 16 issue of JAMA. The most common cause of death in CF is respiratory failure secondary to pulmonary infection. The prevalence of MRSA in the respiratory tract of individuals with CF has increased substantially, and is now more than 20 percent, according to background information in the article. However, the effect of MRSA on outcomes in CF is unclear.

Elliott C. Dasenbrook, M.D., M.H.S., of Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, Cleve­land, and colleagues conducted a study to examine the association between MRSA and survival in CF. The study included 19,833 CF patients (ages 6 to 45 years) who were enrolled in the study January 1996 and December 2006, with follow-up until December 2008. Various analytic models were used to compare survival between CF patients with and without respiratory tract MRSA.

During the study period, 2,537 patients died and 5,759 individuals had respiratory tract MRSA detected. The mortality rate was 18.3 deaths per 1000 patient-years for patients without MRSA and 27.7 deaths per 1000 patient-years for those with MRSA. After adjustment for various factors associated with severity of illness, the risk of death was approximately 1.3 times greater for CF patients when MRSA was detected compared with when MRSA was not detected.

"These findings suggest that MRSA may be a poten­tially modifiable risk factor for death in CF," the authors write.

"The results of this study in conjunc­tion with previous data further estab­lish MRSA as a significant CF pathogen and provide impetus for more aggressive treatment of CF patients who are persistently MRSA positive. Ide­ally this treatment will be conducted in the context of clinical trials, because op­timal therapeutic approaches for MRSA, both persistent and new, are not yet known. The study results also rein­force the importance of following cur­rent CF infection control guidelines to minimize transmission of MRSA, par­ticularly in outpatient clinics with high CF patient volume."

Source: JAMA and Archives Journals