Small Colonies, Bigger Problems? New Evidence That Staphylococcus aureus Small Colony Variants Can Worsen Lung Inflammation in Cystic Fibrosis Rats.

Staphylococcus aureus is the most prevalent cystic fibrosis (CF) pathogen. During chronic airway infections, S. aureus adaptation to antibiotics includes evolving small colony variants (SCVs). Observational studies correlate SCVs with deteriorating lung function in CF, but it is unclear whether SCVs cause disease progression or if they are markers of intensified treatment. G. E. Bollar, J. D. Keith, A. M. Oden, M. R. Kiedrowski, and S. E. Birket (Infect Immun 90:e00237-22, 2022, https://doi.org/10.1128/iai.00237-22) provide intriguing new experimental evidence that an SCV elicits greater inflammation than its normal colony progenitor strain in CF rats.