Bacteriological Study of Chronic Suppurative Otitis Media with Reference to Aerobes

Abstract

Background : Chronic suppurative otitis media ( CSOM) is a disease of multiple etiology and is well known for its persistence and recurrence in spite of treatment. Its importance lies in its refractoriness to treatment and chronicity leading to complications. CSOM is most likely a result of incomplete or unsuccessful treatment. Aerobic bacteria either in single or mixed culture and also resistant strains like MRSA and ESBL producers are responsible for most of CSOM cases. Indiscriminate use of antibiotics leads to resistance and poor follow up have resulted in persistent low grade infection, refractoriness to treatment, complications of CSOM and postoperative complications. Hence knowledge of microbacteria and sensitivity pattern is necessary in all CSOM cases for better outcome. Objectives : To isolate and identify the aerobic bacterial flora of CSOM and to study the antibiotic sensitivity pattern of isolates with special reference to MRSA and ESBL production and follow up of patients after antibiotics susceptibility testing and to record the response to therapy. Methodology : Clinically diagnosed new cases of CSOM ( tubotympanic ) of all age groups and both sexes attending ENT Out Patients Department at KLE’s DR.Prabhakar Kore Hospital and MRC,Belgaum. Patients with otorrhoea more than two months duration are taken by random sampling technique. Two ear swabs collected from each patient studied with gram stain, culture and morphology of colony and identification of organism by standard methods. Antibiotic susceptibility done in all cases. MRSA and ESBL production detected by using standard methods. Results : Ninety nine CSOM patients and their isolates were studied for a period of one year. Majority of patients were in the age group of 11-20years,56.4% were males and 43.4% were females. Majority were from rural areas ( 72.7% ) and unilateral infection ( 76.8% ) was more common than bilateral.Right side ( 40.4% ) was more commonly affected than left. Maximum number of cases were seen during the month of November to February ( 44.4% ) . Gram stain showed pus cells and organism ( 78.8% ) of isolates. IV Total number of gram negative ( 41.4% ) isolates were more than gram positive ( 31.3% ) bacteria. S.aureus ( 29.3% ) was the common organism isolated followed by P.aeruginosa and S.aureus + P aeruginosa ( 21.4% ) was the common mixed isolate. Among S.aureus, MRSA isolated in 51.7% and among gram negative bacteria 31.7% ESBL producers were isolated. S.aureus was sensitive to Gentamicin ( 72.4% ) , Amoxyclav ( 66.5% ) and Ciprofloxacin( 44.8% ) and sensitivity to Ampicillin( 27.6% ) and Erythromycin( 35.5% ) was less. P.aeruginosa and other gram negative bacteria were sensitive to Amikacin( 70100% ) ,Cefotaxime ( 50-100% ) ,Amoxyclav ( 50-100% ) and Levofloxacin( 68-100% ) . Sensitive to Erythromycin ( 16-50% ) was observed less but sensitive to Ciprofloxacin was moderate ( 50-60% ) . Sensitivity pattern of mixed cultures was varied ( but most of them were sensitivity to Amikacin,Cefotaxime and Levofloxacine than Ampicillin and Erythromycin ) . MRSA showed moderately sensitivity to Gentamicin,Ciprofloxacin and Amoxyclav and resistant to Ampicillin,Erythromycin and Ceftazidime. Amomg ESBL producers were sensitive to Amikacin and Levofloxacin, but resistant to Erythromycin and Cefotaxime ( moderatively sensitivity to Amoxyclav and Ciprofloxacin) . Combinations of MRSA + ESBL isolates were resistant to all drugs, MRSA+Non -ESBL isolates were variable in sensitivity.Only ESBL isolates shows resistant to third generation Cephalosporins ( Ceftazidime and Cefotaxime ) but sensitivity to Amikacin,Levofloxacin and Amoxyclav ( for Ciprofloxacin and Erythromycin variable sensitivity were seen) . Conclusion : Commonest isolate of CSOM was S.aureus followed by P.aeruginosa. Among S.aureus 50% of them were MRSA and mixed isolates were also seen significantly. Single isolates were resistant to routine antibiotics but susceptible to newer antibiotics like Amikacin, Levofloxacin and Cefotaxime. Majority of MRSA were resistant to most drugs and ESBL producers resistant to third generation Cephalosporins. Mixed cultures of MRSA and ESBL showed varied sensitivity pattern. So isolation of bacteria and study of sensitivity pattern is necessary in all the CSOM cases for better patient out come in both pre and postsurgical cases and also in preventing drug resistance