Evaluation of bacterial flora and antimicrobial susceptibility of chronic suppurative otitis media at the Kenyatta national hospital a prospective study

Abstract

Main objective: To determine the bacteriological flora of CSOM and its antimicrobial susceptibility at the KNH. The WHO definition of CSOM was applied in this study. Study design: Cross sectional descriptive study Setting: Kenyatta National Hospital's ENT H&N out patient department. Methodology: Middle ear swabs were taken on the first day of contact with the patient using sterile cotton wool swabs and ear specula. Specimen were analysed for bacteriology using UON laboratory and operating procedures. A wide range of antibiotics including those used to treat CSOM were tested for sensitivity against various microorganisms using disc diffusion method. Results: There were more males (57%) than females (43%) in this series. The mean age was 20 years and the commonest age group was between 1-15 years. 66% of the patients captured reported previous use of topical ear drops while 17% had used systemic antibiotics. The frequency of bilateral disease was 22%. Pure cultures were obtained in 82% of samples while 17% were mixed and in 1 % there were no organisms isolated. The organisms isolated were staph aureus 39%, Pseudomonas aeruginosa 36%, proteus 6% and E. coli 6%. Anaerobes were only identified by gram stain and constituted 4% of the isolates. Fungal isolates formed 2% of the total (Aspergillus and C. albicans). Staph. aureus demonstrated significant resistance to fluoroquinolones. Conclusions: The micro-organisms causing CSOM at the KNH are similar to those found in other centres of the world but antibiotic sensitivity patterns appears to change with time. Significant resistance to fluoroquinolones especially by S. aureus raises much concern. CiprofJoxacin is commonly used to treat CSOM at the KNH. Anaerobic organisms play a significant role in causation of CSOM. They are fastidious and require stringent techniques for specimen collection, transportation and isolation in the laboratory and probably contribute a higher percentage than what we found in this series.