© 2015 The Authors. Antibiotic therapy in patients currently treated with corticosteroids is common in chronic respiratory diseases when exacerbation symptoms attributable to infection appear. Among them, obstructive diseases such as asthma and chronic obstructive pulmonary disease (COPD) are major health issues affecting hundreds of million people worldwide that are frequently treated with inhaled corticosteroids. Systemic corticosteroids are also used for idiopathic pulmonary fibrosis, a less prevalent chronic respiratory disease. In this issue of EMBO Molecular Medicine, Earl et al (2015) report a potentially baleful relationship between steroid and antibiotic treatment in chronic respiratory diseases, affecting colonization persistence and antibiotic tolerance for Haemophilus influenzae, one of the leading potentially pathogenic microorganisms (PPMs) of the respiratory system.