Outcomes of cystic fibrosis pulmonary exacerbations treated with antibiotics with activity against anaerobic bacteria

Abstract Background Obligate and facultative anaerobic bacteria are prevalent in cystic fibrosis (CF) airways. Increases in anaerobe relative abundance have been associated with CF pulmonary exacerbations (PEx); however, the impact of antibiotic treatment of anaerobes during PEx is unknown. We hypothesized that PEx treated with antibiotics with activity against anaerobes would improve outcomes compared to antibiotics without anaerobic activity. Methods This was a single-center, retrospective study of people with CF, ages 6 years and older, treated with intravenous (IV) antibiotics for PEx. IV antibiotics were classified as either broad or minimal anaerobic activity. PEx treated with broad anaerobe coverage were propensity-score matched to PEx treated with minimal anaerobic coverage. The primary outcome, % of baseline % predicted forced expiratory volume in one second (ppFEV1) recovered, was compared between antibiotic categories with a linear mixed model. The secondary outcome, time to next PEx, was assessed using a Prentice Williams Petersen model. Results 514 PEx from 182 patients were included. Broad anaerobe coverage was used in 27% of PEx, and was used more often for older patients (p  Conclusions In this single center, retrospective study, antibiotics with broad activity against anaerobes were not associated with improved outcomes of CF PEx.