Bacteriology of postradiotherapy chronic rhinosinusitis in nasopharyngeal carcinoma patients and chronic rhinosinusitis.

The purpose of this study was to investigate and compare the bacteriology of postradiotherapy chronic rhinosinusitis (postRT-CRS) and chronic rhinosinusitis (CRS) by evaluating the aspiration materials of the maxillary sinus of patients with postRT-CRS and patients with CRS. We collected the secretions of the maxillary sinus from 30 nasopharyngeal carcinoma patients with postRT-CRS and 30 patients with CRS for aerobe/facultative anaerobe bacteria culture. The most common isolates in the postRT-CRS group were Streptococcus viridans, Staphylococcus aureus and Haemophilus influenzae, while those in the CRS group were Haemophilus influenzae, Pseudomonas aeruginosa and Staphylococcus aureus. Isolated gram-positive coccus rate in postRT-CRS patients was significantly higher than in CRS patients (62.50% compared with 30.00%, respectively; P < 0.05), and isolated gram-negative bacilli rate in postRT-CRS patients was significantly lower than in CRS patients (31.25% compared with 70.00%, respectively; P < 0.05). However, the incidence of positive cultures was not significantly different between the postRT-CRS group and the CRS group (P > 0.05). This study found that there were some differences in bacteriology between postRT-CRS and CRS. Gram-positive coccus was the predominant aerobic/facultative anaerobe pathogenic bacterium in patients with postRT-CRS, and gram-negative bacilli was predominant in CRS patients.