Clinico-epidemiological Characteristics and Risk Factors Associated with Multidrug- resistant Bacterial Ear Infections at a Tertiary Care Centre in Northern India: A Retrospective Analytical Study

Introduction: A total of 360 million people worldwide have been reported to suffer from hearing loss. The most common cause of ear infection is otitis media, which can be attributed to bacterial pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae. Aim: To identify the incidence and risk factors associated with multidrug-resistant bacteria causing ear infections at a tertiary care centre in India. Materials and Methods: A retrospective analytical study was conducted in the Bacteriology section of the Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, from January 2021 to January 2023, and analysed in February 2023. A total of 83 ear discharge samples sent to the laboratory were included in the duration of the study and all clinical and laboratory data were extracted from the hospital information system and the laboratory register, respectively. All pathogens were identified using routine biochemicals and Matrix-assisted Laser Desorption/ Ionisation- Time of Flight-Mass Spectrometry (MALDI-TOF-MS) assay, and their antibiotic susceptibility testing was performed using the Kirby Bauer Disc Diffusion method. Statistical analysis was performed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) software version 20.0 (SPSS Inc.). The Chi-square test was used for all categorical variables, and the comparison of two means was performed using GraphPad Prism version 9.5.1 (GraphPad Software Inc.), with p-value<0.05 considered statistically significant. Results: The mean age of the participants in the present study was 35.39±20.93 years and majority, 56 (67.47%) participants were males. Among total 83 samples, 69 (83.13%) patients with suppurative bacterial ear infections. Postoperative conditions in 40 (48.19%) samples and respiratory allergies in 36 (43.37%) samples were the most common risk factors associated with ear infections. Postoperative conditions (p-value=0.005) and Diabetes Mellitus (DM) (p-value=0.026) were statistically significant risk factors for developing ear infections. Pseudomonas aeruginosa was recognised as the most common pathogen in 22 acute cases and 10 chronic cases of otitis media. For all the antimicrobial agents tested, the highest resistance was observed towards fluoroquinolones in 51/67 (76.11%) samples, followed by extended-spectrum beta- lactams in 43/67 (64.18%) samples. Conclusion: The current study describes the incidence and risk factors associated with multidrug-resistant ear infections, the spectrum of pathogenic microbial isolates and their drug susceptibility, aiming to prevent morbidity and complications leading to the loss of auditory function.