Microbiological Profile and Antibiotic Sensitivity of 100 Cases of Otitis Externa

Abstract

Otitis externa is a common condition encountered in the ENT outdoors. For long, it was thought to be of fungal etiology but after World War II, bacterial pathogens were found to be most commonly involved. Pseudomonas has been described as the most common causative organism in the literature. This prospective study aimed to study the microbiological profile and antibiotic sensitivity of 100 patients of otitis externa. 100 diagnosed cases of otitis externa were included in the study after informed consent. Swabs were taken from the external acoustic canal maintaining asepsis. The swabs were analysed using microscopy, culture and sensitivity testing. The samples were cultured on blood agar, MacConkey agar and Sabourad's dextrose agar with antibiotics. Antimicrobial susceptibility testing was done by Kirby-Bauer disc diffusion method. The most common bacteria identified was Pseudomonas aeruginosa (36.36%), followed by Staphylococcus aureus (15.45%), Escherichia coli (2.73%), Klebsiella (1.82%), and Proteus sp (1.82%). Aspergillus sp (19.09%) and Candida albicans (8.18%) were the fungal species identified. Pseudomonas showed excellent sensitivity to imipenem, piperacillin and ofloxacin, while Staphylococcus showed good sensitivity to vancomycin, ofloxacin and netilmycin. Topical fluoroquinolones can be used as empirical treatment in most cases of bacterial otitis externa. In resistant cases, culture and antibiotic sensitivity should be done to manage the infection.

Keywords: Antibiotic sensitivity; Ofloxacin; Otitis externa; Pseudomonas.

Fig. 1

Culture results of 110 ears of 100 cases

Fig. 2

Distribution of isolated pathogens