Investigation of bacterial microbiota and risk factors in dogs with external ocular diseases from Bandeirantes, Paraná State, Brazil

Resumo

For the determination of the bacterial etiology of the external ocular diseases and sensitivity to antimicrobials, 38 dogs with external ocular diseases, unilateral or bilateral, and 120 dogs without ocular diseases (control group), were studied between 08/2008 and 07/2009 in the Veterinary Hospital of North Paraná State University, Brazil. The collected samples of the inferior conjunctival sac were incubated at 37ºC in an aerobic environment, in blood agar and MacConkey agar, for 120 hours. After the presumptive identification, the bacterial species were identified by the systems APISTAPH (bio- Merieux, Incorporation), API 20 STREP (bio-Merieux, Incorporation) and BACTRAY (Laborclin, Ltd.) and incubated in Mueller-Hinton agar with antimicrobials disks, for sensitivity determination. For the risk factors, the owners answered a questionnaire with epidemiological variables. There was microorganism growth in 46 (73.02%) samples, with isolation of one microorganism in 42 samples and two microorganisms in four. Gram-positive bacteria corresponded to 76% of the isolated, Gramnegative 20% and yeasts fungi 4%. Staphylococcus spp totalized 66% of isolated, with S. aureus (24%) and S. intermedius (24%) the most prevalent. With the exception of S. intermedius (91.67%) and S. epidermidis (66.67%), the isolated bacterial species presented 100% resistance to the sulfonamide. The S. aureus isolated presented 91,67% sensitivity to chloranphenicol, tobramycin and amoxicillin/clavulanic acid, and the same percentile of resistance to tetracycline. The S. intermedius presented 100% sensitivity to amoxicillin/ clavulanic acid and 91,67% to gentamicin and 75% resistance to tetracycline and ceftriaxone. The associations of risk for external ocular diseases were clinical returns (OR=59,50, 7,29<OR<1305,07, p=0,00000), use of topical antibiotics (OR=19,67, 3,59<OR<142,50, p=0,00003), use of topical corticoids (OR=19,83, 2,08<OR<474,07, p=0,00232) and ocular cleansing (OR=23,00, 6,80<OR<82,90, p=0,00000). The realization of microbiological examinations is essential for the adequate treatment of ocular diseases.