Etiological agents of CSOM and its sensitivity pattern

ABSTRACT

The present study was undertaken with the aim to detect bacteria and fungi as aetiological agent in CSOM and to see susceptibility pattern of bacterial isolates to different antibiotics and to determine the beta lactamase production by the bacterial isolates. Experimental Study. This study was conducted in the department of Microbiology, Basic Medical Sciences Institute, JPMC, Karachi, during the period of August 1998 to February 1999. During this period, 110 patients were seen, of them 62 were male and 48 were female with male to female ratio of 1.31. Two swabs were taken from each patients ear, one was put immediately in to Brain Heart Infusion [BHI] broth and the other was inoculated on Sabouraud Dextrose Agar [SDA] slant. BHI was incubated for 2-4 hours and subcultured on blood agar, chocolate agar and MacConkey's agar plates. The Chocolate agar was incubated in 5-10% CO[2] atmosphere in a candle jar and they were incubated for 24 hours at 37°C. SDA slant was incubated for 14 days at 37°C. Isolates were identified by Gram staining and then confirmed by biochemical test. Fungus growth was stained in Lactophenol Cotton blue [LPCB] and identified microscopically. Amongst bacterial isolates gram negative rods [41] and Pseudomonas aeruginosa [45] were predominant. 47 gram positive cocci were seen, of those 37 were Staphylococcus aureus. Fourteen fungal isolates were recovered, all of them were found to be Aspergillus species. Bacterial isolates were tested for beta-lactamase production the drug sensitivity was noted by disc diffusion method on Mueller Hinton agar. Ciprofloxacin and Enoxacin emerged as the most effective antibiotics. Tobramycin also showed good results against gram negative rods and Pseudomonas aeruginosa. Chloramphenicol, Clarithromycin and Minocycline showed good results against Staphylococcus aureus. And other gram positive cocci. Drug sensitivity of the fungi was not done. Micro-organisms showed least sensitivity to Ampicillin and Cotrimoxazole. It is concluded that to achieve the maximum benefits of antibiotics, we must use them with discrimination and with the understanding of microbial population and with the knowledge of their indications and limitations. The indiscriminate, haphazard and halfhearted use of antibiotics and poor follow up of patients causes more harm than good