Antimicrobial susceptibility pattern of pathogenic bacteria of Chronic Suppurative Otitis Media (CSOM) patients through culture and sensitivity in a tertiary level hospital in Khulna

Background: Chronic Suppurative Otitis Media (CSOM) is a chronic disease associated with irreversible consequences and serious intracranial and extracranial complications. Thereby early & effective treatment must be needed to avoid such complications. Objectives: This study was carried out to know antimicrobial susceptibility pattern of pathogenic bacteria through culture and sensitivity for better management and to reduce resistance & morbidity due to CSOM. Methods: After taking proper approval from hospital administration, this study was conducted on 82 patients of clinically diagnosed cases of both Tubo-tympanic & Attico-antral variety of CSOM attending ENT OPD of Gazi Medical College Hospital, Khulna from January 2018 to June 2018. After proper sample collection by sterile aural swabs, they were immediately sent to the microbiology laboratory of Gazi Medical College Hospital, Khulna for bacterial culture, isolation and identification. Routine antibacterial susceptibility was done as per CLSI guidelines. SPSS 18.0 was used for statistical analysis. Results: The commonest pathogens isolated were Staphylococci, Coagulase Negative Staphylococci (CONS), Pseudomonas aeruginosa, Klebsiella spp. & others; mostly showing susceptibility to high end antibiotics like Ceftriaxone and Amoxiclav for staphylococcal infection & piperacillin-tazobactum for Pseudomonal infection. Conclusion: Antibiotic sensitivity pattern determines the prevalent bacterial organism causing CSOM to start empirical treatment for a successful outcome, and thus to prevent the emergence of resistant strains.


Materials and methods
After taking approval from hospital administration, this prospective observational study was conducted for a period of 6 months from January 2018 to June 2018 on 82 selected patients of clinically diagnosed cases of both Tubo-tympanic & Attico antral variety of CSOM attending ENT OPD of Gazi Medical College Hospital, Khulna. Patients of all ages and both sexes presenting with tympanic perforation and ear discharge of more than 3 months and patients who were not on any antibiotics (oral and systemic) in the previous five days were included in the study whereas patients with systemic diseases and ear discharge for less than three months were excluded from study. Informed consent was obtained at enrollment. The results were analyzed statistically after entering in excel worksheet by using SPSS 18.0 version.

Sample Collection
Before collecting the aural discharge, the external auditory canal was cleared of cerumen swabbed with boric acid spirit and allowed to dry. The external ear discharge was then aseptically collected in naked eye with a thin, sterile cotton swab without touching tympanic membrane or the external auditory canal. Collected specimens were transported immediately to the laboratory for further processing.

Specimen processing and susceptibility testing
The swabs were inoculated onto MacConkey agar and nutrient agar for aerobic culture. After overnight incubation at 37°C, growth of microorganisms were examined, then after proper biochemical tests, species level identification was done and antimicrobial susceptibility testing for isolated bacteria was performed using Disc diffusion method by following CLSI guidelines.

Introduction
Chronic suppurative otitis media (CSOM) is a chronic inflammatory disease of mucoperiosteal lining of the middle ear cleft with permanent perforation, ear discharge and hearing loss. It may be acute, subacute and chronic. 1,2 Otitis media is highly prevalent worldwide3 involves 65-330 million individuals with ear discharge, of which 39-200 million suffer from significant hearing impairment commonly in developing and developed countries. 4,5 Over 90% of cases are seen in the South-east Asia. 4 Most of the microbiological studies of CSOM have revealed that the most common aerobic pathogen frequently found in CSOM are Staphhylococcus aureus, Pseudomonas, Gram negative organisms such as Proteus spp, Klebsiella spp, Escherichia coli, Haemophillus influenzae, and Moraxella catarrhalis. 6-8 Untreated cases of CSOM can result in a wide range of complications like persistent otorrhoea, conductive deafness, mastoiditis, labyrinthitis and facial nerve paralysis to more serious intracranial abscesses or thromboses. 4,5 Among these all these complications, hearing loss is the most common and preventable one. 5 CSOM is a public health problem not only because of its high incidence and complications but also because of antimicrobial resistance. 4 Development and spread of resistant bacteria due to the over and indiscriminate use of antibiotics was a global public health threat. 3 The improper and indiscriminate use of antimicrobials and poor follow up of patients resulting high percentage of resistant bacteria regarded as a leading cause for recurrence and persistence of low grade infections. [8][9][10] However, antimicrobial susceptibility profile of bacteria in CSOM vary with time and geographical area due to local antimicrobial prescribing practices and prevalence of resistant bacterial strains. 4,5 So, it is very important for the physicians to know about antimicrobial sensitivity pattern for achieving appropriate management of CSOM disease. Majority of the patients (45.12%) were in the age group of 21-40 years (45.12%) (Table 01).

Discussion
The CSOM is a major health problem worldwide, but more in developing countries. It has a negative impact on the development of speech, language and social interaction due to chronic hearing loss and is also responsible for significant morbidity and mortality due to its complications. 2  The organisms were resistant to commonly used drugs like cefuroxime, azithromycin, linezolid, cephalexin. This might be due to irrational use of broad spectrum antibiotics. Prescription of antibiotics without proper investigation can contribute to high level drug resistant pattern. Therefore, drug prescription for patients should be based on laboratory evidence.

Conclusion
Present study provided the information of bacteriological profile and their antimicrobial susceptibility in CSOM patients through culture and sensitivity which proved successful management of these cases. Staphylococcus aureus and Pseudomonas spp. were found to be the major pathogens in CSOM. Staphylococcus aureus was highly sensitive to ceftriaxone, amoxiclav, cefepime and piperacillin-tazobactum, meropenem and ceftriaxone were found to be most sensitive for strains of Pseudomonas spp. So, periodic evaluation of regional antimicrobial sensitivity pattern should be encouraged for successful treatment of CSOM and thus minimizing its complications and preventing antibiotic resistance.