Cytological and Bacteriological Evaluation of Tracheal Aspirates for the Diagnosis of Lung Affections in Horses

Transtracheal wash technique is commonly employed for collecting aspirates and determining the bacterial agents involved in lower respiratory tract infections by culture examination. In addition, the cytologic analysis of transtracheal wash is also useful for diagnosis and differentiation of lower respiratory diseases of inflammatory and non-inflammatory origin. In present study four horses (two foals and two adult horses) with frank respiratory signs, inflammatory leukogram and radiologic findings suggestive of respiratory involvement were subjected to transtracheal wash collection. Cytology of the stained smears and culture examination revealed Rhodococcus equi in two horses whereas in other two horses, Staphylococcus spp. was isolated. Isolates of Rhodococcus equi were sensitive to erythromycin, amoxicillin, streptomycin, neomycin, norfloxacin and sulfadiazine, whereas Staphylococcus isolates were found sensitive to amoxicillin, ampicillin, doxycycline, gentamicin, neomycin, erythromycin, oxytetracycline, penicillin and streptomycin and resistant to ciprofloxacin and norfloxacin. Two horses (treated with amikacin and penicillin) and one foal (treated with erythromycin and rifampicin) responded to recommended doses of antibiotic therapy and recovered smoothly.