Analysis of the current Bacteriological Profile and Antibiotic Susceptibility Patterns of Organisms Isolated from Aural Swabs in a Tertiary Care Hospital in Dhaka, Bangladesh
Author(s): Shaheda Anwar, SM Ali Ahmed, Ismet Nigar, Rehana Razzak Khan, Sanjida Khandakar Setu, Abu Naser Ibn Sattar, Chandan Kumar Roy, Sharmeen Ahmed, Ahmed Abu Saleh
Background: Aural discharge, or ear discharge, can be caused by several factors, including ear infections (otitis media or externa), eardrum perforation, or the presence of foreign objects in the ear. Conditions like cholesteatoma, trauma to the ear, and complications from ear surgery may also result in discharge. If accompanied by pain or hearing loss, medical attention should be sought for proper diagnosis and treatment. The inappropriate use of antibiotics has resulted in the development of antibiotic resistance.
Objective: This study aimed to identify bacterial isolates from aural discharge and to determine their susceptibility pattern.
Methods: This retrospective study was conducted in the Department of Microbiology and Immunology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh, between January 2023 and June 2024. Two hundred fifty-eight aural swabs with discharge were collected, and the bacterial profile was retrieved. The collected samples were cultured using standard techniques in a medical microbiology laboratory. The isolated bacteria were identified by colony morphology, gram staining, and biochemical reactions. Antibiotic susceptibility was tested by Kirby Bauer disc diffusion methods per the National Committee for Clinical Laboratory Standards guidelines.
Result: A total of 258 aural discharges were collected, of which 68 (26.35%) were culture positive. Among 68 bacterial growths, the majority of culture-positive cases were in the age group 11-20 years (44.11%), and of them 58.13% were female. Out of 68 culture growth, 50 (73.53%) were Gram-negative bacteria, and 18 (26.47%) were Gram-positive bacteria. Pseudomonas spp. (47.05%) was the prevailing isolate, followed by Staphylococcus aureus (26.47 %), Klebsiella spp. (17.65%), Acinetobacter spp. (10.95%). Among Gram-negative isolates, Pseudomonas spp., Klebsiella spp, Acinetobacter spp. showed higher sensitivity to colistin, piperacillin-tazobactam, and good sensitivity to meropenem, cefepime. All the gram-negative isolates exhibited higher resistance to cephalosporins, monobactams, trimethoprim-sulfamethoxazole. Among the aminoglycosides and fluoroquinolones-ciprofloxacin resistance was higher (61.1% to 75%), followed by amikacin and gentamicin (50%-61.1%). Among gram-positive isolates, Staphylococcus aureus exhibited highest susceptibility to linezolid and vancomycin (100%), followed by gentamicin (50.0%) and cloxacillin (44.44%). High levels of resistance were observed to amoxicillin and cephalexin (88.89%), cotrimoxazole (83.33%), and erythromycin and ciprofloxacin, both with a resistance rate of 61.11%. About 12.03% of Staphylococcus aureus were methicillin resistant which were sensitive to gentamicin, vancomycin, and linezolid.
Conclusion: The findings of this study reveal a significant isolation rate from aural samples, highlighting an alarming increase in antibiotic resistance among both gram-positive and gram-negative bacteria, which could result in treatment failures. These results underscore the necessity for judicious use of antimicrobials in managing ear infections whether acute suppurative media or chronic suppurative otitis media and the implementation of an antimicrobial stewardship program in tertiary care hospitals across Bangladesh.