Microbiology of acute sinusitis in Mexican patients

Acute bacterial sinusitis is a common disorder affecting children and adults. We performed a study to assess the bacteriology of acute sinusitis in a community hospital in Mexico City. Patients with an acute exacerbation of persistent sinusitis or acute sinusitis were enrolled. Aspiration of sinus secretions was performed and aspirates were sent for culture. All patients received antibiotic treatment for the infection based on microbiologic sensitivity reports. Follow-up consultation included endoscopy and a computed tomography scan of paranasal sinuses to assess response to treatment. A total of 110 patients were enrolled for evaluation. Forty nine percent of patients were women; median age was 31 years. A total of 136 cultures were recovered for analysis. Twenty seven percent of cultures were negative. Isolated organisms were Haemophilus influenzae (26%), Moraxella catarrhalis (15%), Streptococcus pneumoniae (14%), methicillin-sensitive Staphylococcus aureus (7%), enterobacteriaceae (6%), Pseudomonas aeruginosa (2%) and miscellaneous (3%). Twenty eight percent of H. influenzae strains were resistant to ampicillin. Penicillin-sensitive S. pneumoniae (PSSP) and penicillin-intermediate-resistant S. pneumoniae (PISP) accounted for 21% and 79% of the S. pneumoniae strains, respectively. H. influenzae was the most common isolated organism. About 55% of those isolates were found in patients <18 years old and only 25% were resistant to ampicillin. Sinus endoscopy continues to be a useful diagnostic tool in addition to imaging studies in sinus infection and should be pursued by the clinician whenever feasible.