The Sense and Nonsense of Antimicrobial Susceptibility Testing in Cystic Fibrosis

Area of Science:

• Pulmonary Medicine
• Infectious Diseases
• Clinical Microbiology

Background:

• Antimicrobial susceptibility testing (AST) is a long-standing practice for guiding airway infection therapy in cystic fibrosis (CF).
• The clinical benefit of routine AST in improving treatment outcomes for CF patients remains unsubstantiated.
• Current practices may contribute to the overuse of antibiotics.

Purpose of the Study:

• To evaluate the evidence supporting the use of AST in managing airway infections in individuals with CF.
• To determine if routine AST provides tangible benefits to treatment outcomes.
• To explore the potential for selective AST application in CF.

Main Methods:

• Review of existing literature and clinical data on AST in CF airway infections.
• Analysis of factors influencing the predictive value of AST for treatment success.
• Assessment of the impact of routine versus selective AST on antibiotic prescribing.

Main Results:

• Lack of robust evidence demonstrating that routine AST improves treatment outcomes in CF.
• Identification of specific characteristics of CF airway infections that limit AST's predictive accuracy.
• Potential for routine AST to promote inappropriate antibiotic selection and use.
• Recognition that certain aspects of CF infection may still benefit from targeted AST.

Conclusions:

• Routine antimicrobial susceptibility testing may not be beneficial and could lead to inappropriate antibiotic use in cystic fibrosis patients.
• The utility of AST in CF airway infections is limited by disease-specific factors.
• Selective application of AST may offer valuable guidance for antibiotic selection in specific clinical scenarios within CF care.