Bacteriological study of otitis externa and susceptibility


SummeryBack ground Otitis externa (OE) is an inflammation of ear canal between ear drum and the outside of the ear.The aims of the study to isolate and identify the causes of otitis externa, to determine the antimicrobial susceptibility pattern, to detect the seasonal distribution of the OE patient.Material and patient Fifty ear swabs were collected from suspected cases of OE over one year from January to December 2005 in Al-Kindy Hospital. The ratio of male to female was 1.7-1, and the most common ear infection was (40%) of males at age group (10-19) years. Ear swabs were collected and inoculated to blood and maCconkey agar. Morphological identification and biochemical tests for growing bacteria were done. Antimicrobial susceptibility test was carried out.Results This study showed out of 50 ear swabs, 12 swabs (24%) showed no growth while 38 swabs (76%) showed the growth of bacteria, the most common bacteria isolated was Pseudomonas aeruginosa (36%) followed by Proteus mirabilis and Staphylococcus aureus (18%) each and Enterobacter aerogenes (4%). Amikacin was effective antimicrobial agent against P. aeruginosa (61.1%) and Proteus mirabilis (66.6%), while chloramphenicol was effective agent against P. mirabilis (66.6%), S. aureus showed susceptibility to bactrim (septrim), erythromycin, clindamycin (55.5%) each followed by ciprofloxacin (33.3%), while E. aerogenes showed susceptibility to ciprofloxacin (100%). This study showed that P. aeruginosa, E. aerogenes and S. aureus resistant to cefixime, ceftazidime, chloramphenicol. Finally the study showed that 60% of OE was during summer and the least infection was during winter (4%).Conclusions Pseudomonas aeruginosa was the most common bacterial isolates. There is no specific antimicrobial agent against pathogenic bacteria.Keywords: Pseudomonas aeruginosa,, antimicrobial agents