Bacteriological and Mycological study was done in 200 patients with Chronic suppurative otitis media

Bacteriological and Mycological study was done in 200 patients with Chronic suppurative otitis media (CSOM) attending Ear, Nose and Throat out- patient department. A control group included 50 patients with no history of ear disease attending OPD other than ENT department were studied for the presence of bacteria and fungi. The CSOM samples were collected with a sterile swab, transferred and processed in Department of Microbiology, Andhra Medical College, by following the standard protocols.
1. In the study group, culture positive samples were 188 (94%) out of 200 samples. No growth was observed in 12 (6%) samples.
2. In the study group, total number of CSOM cases in males were 118 (59%) and total number of cases in females were 82 (41%). Out of 118 cases in male patients, culture positive cases were, 111. Out of 82 cases in female patients, culture positive cases were 77 respectively. The study shows preponderance of male in culture positive cases.
3. In the study group, total number of cases were more common in 1 – 10year age group 85 (42.5%). This is probably due to straight, wide and short eustachian tube and increase incidence of upper respiratory tract infections. Out of 85 cases, males were 51 (25.5%) and females were 34 (17%).
4. Ear – wise distribution of CSOM cases in the present study revealed that left ear was more affected than right ear. The total number of cases in left ear were121 (60.5%), in right ear were 68 (34%) and in both ears were 11 (5.5%). Among them, males were 118 (59%) and females were 82 (41%) respectively.
5. Distribution of cases demographic area wise showed that higher number of CSOM cases were from rural area than urban area. The total number of cases in rural area were 126 (63%) among them, males were 74 (37%) and females were 52 (26%). Total number of cases in urban area were 74, out of which males were 44 (22%), and females were 30 (15%). This study shows that distribution of cases was more common in low socioeconomic group.
6. Monomicrobial isolates was observed in 158 (84.05%) cases. Polymicrobial isolates was observed in 30 (15.95%) cases.
7. Bacterial isolates were more common than fungal isolates in both pure and mixed infections. Total bacterial isolates were 184 (84.40%), out of which bacteria in pure culture- 128 (58.71%) and mixed culture – 56 (25.68%). Total Fungal isolates were 34 (15.60%), out of which 30 (13.76%) were from pure culture and 4 (1.83%) were from mixed culture.
8. Incidence of Gram- negative organisms 122 (66.30%) were more than when compared to Gram- positive organisms 62 (33.69%).
9. Pseudomonas aeruginosa was the predominant isolate in present study 74 (40.22%), followed by Staphylococcus aureus 38 (20.67%), Proteus species 24 (13.05%), Coagulase negative Staphylococci 20 (10.86%), Klebsiella pneumoniae 14 (7.61%), Escherichia coli 6 (3.26%), Acinetobacter baumanii 4 (2.17%), Micrococci 2 (1.08%) and Corynebacterium species 2 (1.08%).
10. Aspergillus species (18) were the predominant fungal isolates in the present study followed by Candida species (16). Among Aspergillus species, Aspergillus niger 12 (35.30%), Aspergillus flavus 6 (17.64%) were isolated. Among Candida species, Candida albicans 12 (35.30%), Candida tropicalis 2 (5.88%) and Candida parapsilosis 2 (5.88%) were isolated.
11. Most of Gram-negative isolates are sensitive to Imipenem, Amikacin, Piperacillin+ tazobactam, Ceftazidime + clavulanic acid, Ciprofloxacin and Gentamycin.
12. Most of gram-positive isolates were sensitive to Teicoplanin, Linezolid, Vancomycin, Azithromycin, Amikacin and Clindamycin.
13. Among Gram-negative bacilli, Extended spectrum beta-lactamase (ESBL) producers were observed in 25 (20.49%) isolates and Metallo Beta-lactamase (MBL) producers were seen in 11 (9.01%) isolates.
14. Among Gram- positive bacilli, Methicillin resistant Staphylococcus aureus (MRSA) was observed in 27 (12.38%) isolates. (MRSA – Staphylococcus aureus = 18; MRCONS – Methicillin resistant Coagulase negative Staphylococci = 9)
15. Antifungal susceptibility testing of fungal isolates was tested with disc diffusion method. Candida species were sensitive to Amphotericin B (100%), Clotrimazole (100%), and Ketoconazole (100%) and 90% sensitivity to Fluconazole and Itraconazole.
16. Aspergillus isolates (12 strains of Aspergillus niger and 6 strains of Aspergillus flavus) were 100% sensitive to Itraconazole, Nystatin and Clotrimazole and 50% sensitive to Amphotericin B, Ketoconazole and showed maximum resistance to Fluconazole (100% in Aspergillus flavus and 70% in Aspergillus niger).
17. In the control group, culture positivity for bacterial isolates was seen in 28 (56%) cases, and fungal isolates were isolated in 1 (2%) cases. No growth was observed in 22 (44%) cases. Organisms isolated in control group were Coagulase negative Staphylococci 11 (39.28%), Micrococci 10 (35.71%), Corynebacterium species 6 (21.42%) and Candida tropicalis 1 (3.57%).
18. Therapeutic response of the CSOM cases showed, recovery in 140 (74.46%) cases. Out of which, 80 (42.55%) were males, and 60 (31.91%) were females. No response was seen in 32 (17.02%) cases, which could be mainly due to development of cholesteatoma or mastoiditis which needs surgical treatment.
19. With the emerging of drug resistant strains, the present study would be of great help in guiding antibiotic selection and appropriate therapy that will help health care professionals to manage chronic suppurative otitis media patients and lower the mortality and morbidity associated with complications.
20. In the present study, higher incidence of fungal infections was seen during the rainy season followed by summer season. This could be attributed to the hot and humid climate which facilitates the growth of fungi. Prevalence of fungal infections of the ear during moist and humid conditions has been reported previously by several authors (132), (84). (7th Annual workshop on basic and molecular diagnostics in Mycology; Ozcan et.al.2003).