Antimicrobial susceptibility pattern of bacteria isolated from patients with Otitis externa attending a tertiary health-care institution in Sokoto, Nigeria

Abstract

Abstract Background: Otitis externa is the inflammation or infection of the skin of the external auditory canal, may be acute, subacute, or chronic and usually manifests by itching of the ear, otalgia, otorrhoea, aural fullness, and hearing loss. The causative agent is usually bacteria and occasionally fungi but may be associated with a variety of noninfective systemic or local dermatological conditions such as eczema, seborrhea, and contact dermatitis. Aim: This study aimed to determine the risk factors, bacterial profile, and antimicrobial susceptibility pattern of the isolates from patients with Otitis externa. Methods: A descriptive cross-sectional hospital-based study was conducted on 100 patients with Otitis externa. The ear discharge specimens were collected and analyzed by standard microbial techniques. The antibiotic susceptibility profiles were determined for 12 different antibiotics by the standard disk diffusion method. Data were analyzed with SPSS version 25 and the P < 0.05 was considered statistically significant. Results: The age of the 100 participants ranges from 4 to 57 years with a mean age of 18.78 ± 10.67 standard deviation, and the commonly affected age group was 11–20 years. Pathogens were isolated from 77 (62.1%) of the patients. The predominant isolate was Pseudomonas aeruginosa 32 (41.6%), followed by Staphylococcus aureus 13 (16.9%), others include Proteus mirabilis 7 (9.0%), Peptostreptococcus species 5 (6.5%), Escherichia coli 4 (5.2%), Streptococcus pneumonia 4 (5.2%), Klebsiella pneumonia 3 (3.9%), Streptococcus pyogenes 3 (3.9%), Enterobacter aerogenes 2 (2.6%), Fusobacterium species 2 (2.6%), and Bacteroides 2 (2.6%). Ofloxacin showed good susceptibility to isolated aerobes 65 (95.6%), followed by gentamicin 52 (76.5%) and ceftriaxone 50 (73.5%). All isolated anaerobes showed 100% susceptibility to metronidazole and clindamycin. Bacterial isolates identified in this study showed a trend of multiple drug susceptibility, majority (70%) being susceptible to three or more antimicrobials. Conclusions: Majority of the bacterial isolates were susceptible to more than one antimicrobial agent, hence efforts to isolate microorganisms and determine the susceptibility pattern should be strengthened to improve the treatment outcome of Otitis externa instead of the usual trend of empirical treatment.