Evaluation of the spectrum of bacteria encountered in patients with chronic suppurative otitis media with their antibiotic sensitivity pattern


Objectives: The aim of this study was to determine the most frequent bacteria that cause chronicsuppurative otitis media(CSOM) and their sensitivity to various antimicrobials so that an appropriatetherapy can be started promptly while awaiting the results of the culture and sensitivity of the isolate tovarious antibiotics. Methodology: This study was conducted at Alforat teaching hospital in Najaf cityat the ear-nose-throat (ENT) department from December 2010 to April 2011. The swab was taken fromear discharge before starting the antibiotics and cultured on MacConckey agar(Oxoid, England) andblood agar(HiMedia, India).Gram positive bacteria were identified on the bases of colony morphology,Gram staining, catalase test and coagulase test while the Gram negative bacteria were identified byoxidase test and API 20E(API BioMerieux, France). The sensitivity of the isolates to variousantibiotics was tested by Kirby Bauer disk diffusion technique. Results: The study showed thatfemales are more prone to get the infection than males in a ratio of 1.8: 1 and the frequent ages liablefor infection lie between 3months – 15 year, also it revealed that the gram negative bacteria were morefrequent in causing the infection than gram positive bacteria in a ratio of 2.64 :1 and Pseudomonasaeruginosa was the most frequent species that causes CSOM then Staphylococcus aureus and Proteusmirabilis. Pseudomonas aeruginosa was more sensitive to ciprofloxacin than to gentamicin,Staphylococcus aureus also showed more sensitivity to ciprofloxacin than gentamicin, while Proteusmirabilis had the same degree of sensitivity to those 2 antibiotics. Conclusions: 1- Children are moreprone to be infected with CSOM because of their small Eustachian tube and low immunity. 2- Gramnegative bacteria were more common in causing the infection than gram-positive bacteria in this study.3- Pseudomonas aeruginosa was the most frequent bacteria that cause CSOM then Staphylococcusaureus and Proteus mirabilis. 4- Pseudomonas aeruginosa was more sensitive to ciprofloxacin than togentamicin despite the fact that gentamicin is known to be effective against gram negative bacteriaincluding Pseudomonas aeruginosa propably because of antibiotic miss use and genetic mutation ofPseudomonas aeruginosa .