CLINICO-DIAGNOSIS AND THERAPEUTIC MANAGEMENT OF BACTERIAL AND FUNGAL INFECTIONS OF CANINE EAR WITH SPECIAL REFERENCE TO MOLECULAR CHARACTERIZATION OF CERTAIN OTIC PATHOGENS

“CLINICO-DIAGNOSIS AND THERAPEUTIC MANAGEMENT OF BACTERIAL AND FUNGAL INFECTIONS OF CANINE EAR WITH SPECIAL REFERENCE TO MOLECULAR CHARACTERIZATION OF CERTAIN OTIC PATHOGENS” Name of Student: Name of Guide: Sandeep Pundir Dr. D. S. Nauriyal Department of Veterinary Medicine College of Veterinary Science and Animal Husbandry Anand Agricultural University Anand – 388001 (Gujarat) On screening of 2620 dogs presented at the Teaching Veterinary Clinical Service Complex, Zaveri Clinic, Veterinary College, Anand, Gujarat during the period between August 1, 2005 to July 31, 2006, the overall incidence of dermatitis was observed to be 17.67 per cent (463 cases). Of all the dermatological afflictions in canine population, the incidence of otitis externa stood at 21.81 per cent. Out of all the maladies of dogs, the overall incidence of otitis externa stood at 3.85 per cent. Greater number of cases of otitis were observed during summer season (44.55 per cent). The dogs belonging to the age group of 3 years and above showed greater susceptibility (57.43 per cent). German shepherd (38.6 per cent), followed by Spitz and Labrador retrievers (16.83 per cent each) were the most frequently affected breeds. Male dogs showed greater (61.39 per cent) involvement than females. Thirty-seven dogs with apparently healthy ears were found to have yellow to brownish cerumen in the external ear canal. Seventy-six dogs suffering from otitis showed physical manifestations such as erythema, crust formation, foul smelling otic discharge, head shaking, scratching of ear pinnae with paws, pain on palpation of auricular cartilage, and ulceration of the inner aspect of external ear canal. The cytological examination of swabs from apparently healthy ears revealed presence of squamous cells, Gram-positive or Gram-negative micro-organisms, and leukocytes, whereas swabs from clinical cases of otitis showed either Gram-positive and/or Gramnegative organisms. Cells of Malassezia pachydermatis were seen as oval to pea-nut Gram-positive unicellular yeast cells. Bacteriological culture examination of ear swabs collected from 37 dogs with apparently healthy ears resulted in the recovery of monomicrobic isolates from 7 dogs, whereas more than one organism (bacteria with fungal organism) were isolated from 15 dogs. Staphylococcus spp. accounted for 77.27 per cent isolates, followed by Streptococcus spp. , Pseudomonas spp. , and Escherichia coli. The ear exudate swabs from 76 dogs suffering from otitis on bacteriological culture examination resulted in the recovery of 66 isolates. Monomicrobic isolates were recovered from 41 dogs, whereas mixed infection was observed in 25 dogs suffering from otitis in association with other bacteria and/ or fungi viz. Malassezia pachydermatis, Aspergillus spp. Coagulase-positive staphylococci (CPS) accounted for highest number of isolates, followed by Pseudomonas spp. , Streptococcus spp. and Escherichia coli. Mycological culture examination of ear swabs collected from 37 dogs with apparently healthy ears resulted in the recovery of the monomicrobic isolates from 7 dogs, whereas mixed culture was obtained from 15 dogs in conjunction with bacteria. Malassezia spp. accounted for 59.09 per cent isolates, followed by Aspergillus spp. , and Candida spp. The otic exudate swabs from 76 dogs on mycological culture examination resulted in the recovery of 36 isolates. Malassezia pachydermatis was