Isolation and identification of aetiological agent of middle ear infection (otitis media) and their antibiotic susceptibility in Khartoum state

Abstract

Abstract This study was done to investigate the occurrence of the middle ear infections among different ages and gender, besides isolation and identification of the causative aerobic bacteria and fungi that associated with middle ear infections and also to evaluate the antimicrobial activity with certain antibiotics against the isolated bacteria. One hundred samples were collected from Ear Nose Throat (ENT) Hospital of Khartoum. The causative bacterial agents were isolated by using different types of culture media and identified by using biochemical tests. Antimicrobial susceptibility tests for bacteria were performed using modified Kirby Bauer disc diffusion method, and using national committee for clinical laboratory standards (N CCLS). Fungi were isolated and identified by using culture media and examined microscopical examination. Gram-positive bacteria that were isolated in this -study included Staphylococcus aureus (6.4%), Staphylococcus epidermidis (1.8%), Staphylococcus sabrophyiieus (0.9%) Aerococcus viridiarzs (ll.8%), Listeria monocytogenes (0.9%) Bacillus badius (0.9%) ‘Bacillus megatarium (0.9%) and Corynebacterium spp (0.9%). Gram -negative bacteria which were isolated included Aeromonas hydrophila (16.4%), Pseudomonas aeruginosa (4.6%), Proteus mirabilis(3.6%), Proteus vulgaris (1.8%); Proteus rettgeri (1.8%), Proteus vulgaris biogroup2(l.8%), Haemophillus influenza(l.8%), Erwinia herbicola (0.9%), Pseudomonas spp(5.5%) Acaligenes spp(l.8%), Citrobacter fieundii (0.9%), Klebsiella spp(3.6%), Acirietobacter spp(4.6%), Chromobacterium vi0laceium(6.4%). Enterobacter aerogenes , (0.9%), Actinobacillus spp (0.9%), Aerobacter spp (0.9%) and Escherichia fergusonii (0.9%). Antimicrobial susceptibility tests showed that Gram positive bacteria includes Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus sabrophyiticus, Listeria monocytogenes , Aerococcus virialians, Bacillus

megaterium, and Bacilus budius were mostly susceptible to Gentamicin, Ciprofloxacin, Oflaxacin, while all of them were resistant to penicillin. Antimicrobial susceptibility results showed that all Gram-negative bacteria were mostly sensitive to Gentamicin, Ciprofloxacin and Amikacin. Erwinia herbicola was susceptible to all antibiotics except Arnpicillin and Tetracycline. Proteus spp was susceptible to Chloramphenicol, Co-trimexazole, and Gentamicin, while they were susceptible to Ciprofloxacin and Amikacin. Pseudomonas aeruginosa was resistant to Tetracycline and Ampicillin, and susceptible to Gentamicin and Amikacin. The isolated fungi were Aspergillus niger (4.6%), Aspergillus nidulans (0.9%) and Penicillium sp (0.9%). These were isolated from females only, while Aspergillus terreus (0.9%) was isolated from infected male. Candida spp was of isolation percentage of 40% and 60% fiom infected males and females respectively whereas Aspergillus flavous was 75% and 25% from males and females respectively. Females and males who were infected with fungi showed a rate of (64.7%) and (35.3%) respectively. The percentage of chronic otitis media was (58.5%), and acute one was (41.2%). The highest fungi infections with otitis media were found in group aged (1-10) years -old, while patients of less than one year showed no fungal infections.