Equine pastern dermatitis

Abstract

Summary Bacteriological examination of pastern dermatitis in 12 cases resulted in a variable growth of bacterial species. Dermatophilus congolensis was found on direct smear in 2 cases, although only cultured in one of these. Eleven of the cases were treated with a new topical treatment, consisting of a combination of antibacterial agents and humectants ‐ agents that lower water activity (Mud Stop). Ten of these cases showed a good response to treatment, the other showing partial improvement before the treatment was changed.

Outbreak of Dermatophilus congolensis in Grazing Beef Cattle in Northeastern Mexico: First Report

“…It was observed that the microaerophilic conditions helped purify the microorganism, as described by several authors [9,29,30], who also used Haalstra's method [11]. They showed that even though D. congolensis is able to develop in aerobic or anaerobic conditions, it thrives under microaerophilic conditions to 5-10% CO 2 .…”

The prevalence of Dermatophilus congolensis in horses with pastern dermatitis using PCR to diagnose infection in a population of horses in southern USA

“…1,5,6 A study investigated the association of D. congolensis with pastern dermatitis using cytological evaluation and culture. 4 The organism was only identified in two of 12 horses cytologically, only one of which was culture positive for the organism. In all 12 cases, including the case that cultured positive for D. congolensis, a heavy mixed population of organisms was grown, suggesting culture to be an insensitive method for detecting the organisms.…”

“…Dermatophilosis also has been cited as a common cause of this syndrome [1][2][3] but few data are available in the scientific literature to validate this claim or to define the frequency of infection. 4 The causative organism, Dermatophilus congolensis, is a facultative anaerobic actinomycete with worldwide distribution that causes papular to exudative crusting dermatitis, especially along the dorsum. It is an opportunistic pathogen and infection is associated with wet conditions and subsequent tissue maceration.…”

“…5 Dermatophilus congolensis has branching hyphae that form a railroad track appearance on cytological examination. [1][2][3][4][5] Despite this distinctive appearance and the organism's common occurrence in horses, it is often difficult to identify cytologically in chronic lesions. 1,5,6 As many horse owners and handlers often attempt to treat pastern dermatitis empirically, these lesions are frequently chronic by the time a veterinary practitioner assesses them.…”

“…In all 12 cases, including the case that cultured positive for D. congolensis, a heavy mixed population of organisms was grown, suggesting culture to be an insensitive method for detecting the organisms. 4 Multiple PCR assays have recently been validated for the detection of D. congolensis. 5,8,9 A study which utilized quantitative real time PCR (RT-qPCR) confirmed the increased sensitivity of this method compared to traditional cytological methods, where nine of 14 horses with suspect dermatophilosis were found to be cytologically positive for D. congolensis, whereas 11 of these horses were PCR positive.…”