Prevalence and antibiotic susceptibility of Pseudomonas aeruginosa isolated from chronic suppurative otitis media

Abstract

Background: Chronic suppurative otitis media (CSOM) is the most common middle ear infection characterized by recurrent ear discharges or otorrhoea through a tympanic perforation from the middle ear. The organisms isolated from CSOM include both aerobic and anaerobic bacteria. Among  the  bacteria, Pseudomonas aeruginosa ( P. aeruginosa) has been particularly blamed for deep seated and progressive  destruction  of  middle  ear  and mastoid  structures  through  its  toxins  and enzymes. The present study was done to determine the prevalence and antibiotic susceptibility of P. aeruginosa isolated from CSOM. Methods: This was a retrospective study conducted in a tertiary care hospital in South India in March 2016. Data was obtained from the microbiology records from January 2014 to January 2016. Patients who had active ear discharge for at least three months were included in the study. P. aeruginosa was identified by colony morphology, pigment production, characteristic musty or earthy odor. The identification was confirmed by motility and standard biochemical tests. Results: A total of 293 cases of CSOM were included in the study. Microbial growth was seen in 248 (84.6%) cases and remaining 45 cases did not show any growth. Among 248 bacterial growth, 87 (35%) were positive for P. aeruginosa. Most common organism was P. aeruginosa followed by Staphylococcus aureus. Highest resistance was seen with Gentamicin and Ofloxacin and least resistance with Imipenem. The increased resistance to Cephalosporin group is warning sign, as these are potent anti-Psuedomals. Conclusions: P. aeruginosa and Staphylococcus aureus were found to be the common cause of CSOM in the present study. P. aeruginosa was resistant to commonly used antimicrobials. There was no resistance seen with Imipenem and only two strains were resistant to Piperacillin+tazobactum. Regular evaluation of the microbiological pattern and antibiogram of isolates will help in decreasing the complications of CSOM.