Isolated Bacteria and Their Susceptibility to Antibiotics in Chronic Sinusitis : Results of Endoscopically Guided Cultures of Maxillary Sinus Secretions

ABSTRACT

The aim of this study was to identify the pathogens of chronic recalcitrant sinusitis and to obtain information for determining appropriate antibiotics through sensitivity testing. A prospective study was conducted on 100 patients with chronic sinusitis who had undergone endoscopic sinus surgery after failed medical treatment. Specimens were obtained from the maxillary sinuses and sent for bacterial cultures and sensitivity tests. Bacteria were isolated in 75 (75%) of the 100 cases. Aerobic bacteria were isolated in 73 cases (73%). Gram-positive aerobes were recovered in 54 cases (54%) and Gram-negative aerobes in 20 cases (20%). Anaerobes were isolated in three cases (3%). Mixed infections were found in two cases (2%). More than 90% of the aerobic bacteria were resistant to penicillin, and 48.8% of the Staphylococci were resistant to oxacillin. Seventy percent of Gram-positive aerobes were sensitive to trimethoprim-sulfamethoxazole, 75% to clindamycin, and 93% to ciprofloxacin. Ninety percent of Gramnegative aerobes were sensitive to ciprofloxacin, and 95% to trimethoprim-sulfamethoxazole. In conclusion, most of the isolated bacteria were aerobic, and in contrast to previous reports, mixed or anaerobic bacterial infection was not frequent. Among the oral antibiotics tested for sensitivity in this study, ciprofloxacin, trimethoprim-sulfamethoxazole, and clindamycin are most strongly recommended for treating chronic sinusitis refractory to first-line antibiotic treatment.