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Combining Ivacaftor and Intensive Antibiotics Achieves Limited Clearance of Cystic Fibrosis Infections
Journal article   Open access   Peer reviewed

Combining Ivacaftor and Intensive Antibiotics Achieves Limited Clearance of Cystic Fibrosis Infections

Samantha L Durfey, Sudhakar Pipavath, Anna Li, Anh T Vo, Anina Ratjen, Suzanne Carter, Sarah J Morgan, Matthew C Radey, Brenda Grogan, Stephen J Salipante, …
mBio, Vol.12(6), pp.e0314821-e0314821
12/21/2021
DOI: 10.1128/mbio.03148-21
PMCID: PMC8669489
PMID: 34903059
url
https://doi.org/10.1128/mbio.03148-21View
Published (Version of record) Open Access

Abstract

Drugs called CFTR modulators improve the physiologic defect underlying cystic fibrosis (CF) and alleviate many disease manifestations. However, studies to date indicate that chronic lung infections that are responsible for most disease-related mortality generally persist. Here, we investigated whether combining the CFTR modulator ivacaftor with an intensive 3.5-month antibiotic course could clear chronic Pseudomonas aeruginosa or Staphylococcus aureus lung infections in subjects with , who are highly ivacaftor-responsive. Ivacaftor alone improved CFTR activity, and lung function and inflammation within 48 h, and reduced P. aeruginosa and S. aureus pathogen density by ∼10-fold within a week. Antibiotics produced an additional ∼10-fold reduction in pathogen density, but this reduction was transient in subjects who remained infected. Only 1/5 P. aeruginosa-infected and 1/7 S. aureus-infected subjects became persistently culture-negative after the combined treatment. Subjects appearing to clear infection did not have particularly favorable baseline lung function or inflammation, pathogen density or antibiotic susceptibility, or bronchiectasis scores on CT scans, but they did have remarkably low sweat chloride values before and after ivacaftor. All persistently P. aeruginosa-positive subjects remained infected by their pretreatment strain, whereas subjects persistently S. aureus-positive frequently lost and gained strains. This work suggests chronic CF infections may resist eradication despite marked and rapid modulator-induced improvements in lung infection and inflammation parameters and aggressive antibiotic treatment. Recent work shows that people with CF and chronic lung infections generally remain persistently infected after treatment with drugs that target the CF physiological defect (called CFTR modulators). However, changes produced by modulators could increase antibiotic efficacy. We tested the approach of combining modulators and intensive antibiotics in rapid succession and found that while few subjects cleared their infections, combined treatment appeared most effective in subjects with the highest CFTR activity. These findings highlight challenges that remain to improve the health of people with CF.
Adult Aminophenols - administration & dosage Anti-Bacterial Agents - administration & dosage Cohort Studies Cystic Fibrosis - drug therapy Cystic Fibrosis - genetics Cystic Fibrosis - metabolism Cystic Fibrosis - microbiology Cystic Fibrosis Transmembrane Conductance Regulator - genetics Cystic Fibrosis Transmembrane Conductance Regulator - metabolism Drug Therapy, Combination Female Humans Lung - microbiology Male Mutation Pseudomonas aeruginosa - drug effects Pseudomonas aeruginosa - growth & development Pseudomonas Infections - drug therapy Pseudomonas Infections - genetics Pseudomonas Infections - metabolism Pseudomonas Infections - microbiology Quinolones - administration & dosage Staphylococcal Infections - drug therapy Staphylococcal Infections - genetics Staphylococcal Infections - metabolism Staphylococcal Infections - microbiology Staphylococcus aureus - drug effects Staphylococcus aureus - growth & development

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