Case 13

There is an increasing number of opportunist pathogens that may cause acute pulmonary exacerbations of cystic fibrosis as the patient cohort survives longer. However, it can often be difficult to determine if the isolation of these bacteria represents colonization or true infection. Their identification from sputum samples in the microbiology laboratory is also challenging, requires significant scientific expertise, and is assisted by new technologies such as MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry). One such opportunist pathogen is <italic>Stenotrophomonas maltophilia</italic>, for which risk factors include increasing age and recent oral antibiotics, especially carbapenems. However, it is unclear if this bacterium is transmitted from patient to patient unlike with <italic>Pseudomonas aeruginosa</italic>, but all patients with cystic fibrosis should be admitted to a single room when hospitalization is required. Controversies exist regarding the optimal treatment which in the future may include a greater reliance on inhaled antibiotics.