Microbiology of middle meatus in chronic rhinosinusitis.

Nasal endoscopy allows the collection of middle meatus secretion samples and is an alternative method for determining microorganisms in rhinosinusitis. This study assessed endoscopically collected middle meatus secretions in patients with chronic rhinosinusitis (CRS) and compared those findings with ipsilateral maxillary sinus aspirates and microbiological data of healthy individuals. Middle meatus samples were collected from 114 CRS patients for aerobic, anaerobic, and fungal cultures; maxillary sinus secretions were collected from 13 of these patients. Twenty-three healthy volunteers served as controls. Aerobes were isolated in 86% of CRS patients, anaerobes were isolated in 8% of CRS patients, and fungi were isolated in 11% of CRS patients; the most frequent microorganisms were Staphylococcus aureus (36%), coagulase-negative Staphylococcus (20%), and Streptococcus pneumoniae (17%). Middle meatus and maxillary sinus cultures presented the same pathogens in 80% of cases. In healthy individuals, coagulase-negative Staphylococcus (56%), S. aureus (39%), and S. pneumoniae (9%) were the most frequent isolates. The culture of endoscopically collected middle meatus secretions is effective in identifying microorganisms in CRS patients.