Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2008
Publication Date: 6/1/2008
Citation: Hoopes, J.T., Donovan, D.M., Sussman, D.J., Trayer, T.P., Stark, C.J., Nelson, D.C. 2008. Use of a bacteriophage lysin for barnyard decontamination of Streptococcus equi. American Society for Microbiology.
Technical Abstract: Equine strangles is a highly contagious purulent lymphadenitis of the head and neck that is caused by Streptococcus equi (S. equi subsp. equi). Acute swelling and subsequent abscess formation is found in the submaxillary, submandibular, and retropharyngeal lymph nodes causing a “strangling” of the pharynx . The route of transmission is through nasal secretions and drainage from abscesses. Infected horses can nasally shed bacteria for weeks contaminating surfaces through which other horses can become infected. Attenuated live and deletion mutant vaccines exist, but they are often associated with abscess formation at the site of injection, short duration of immunity, poor efficacy, and the very real threat of infection from the vaccine. Thus, strangles continues to be a serious and common disease of horses despite the presence of multiple vaccines. Prevention strategies are aimed at good hygiene practices, isolation of infected animals, and removal of equipment for sanitization where possible. None of the currently approved sanitizers are safe for use in the presence of horses due to potential toxicity. We have recently been developing PlyC and other bacteriophage lysins (cell wall hydrolases) for decontamination and therapeutic use against veterinary and human pathogens. The PlyC enzyme is specific for streptococcal cell walls bearing a polyrhamnose epitope that include S. equi subsp. equi (group C streptococcus). Significantly, 10 ug of PlyC was shown to completely lyse 5x106 S. equi within 30 seconds by plate assay. Similar results were obtained when testing was extended to a dozen recent clinical isolates of S. equi subsp. equi as well as other group C streptococci (i.e. S. equi subsp. zooepidemicus). ATCC strain 9528 was chosen for use in disinfectant studies where the ability of a PlyC aerosol to decontaminate common stall items such as feed buckets, water troughs, salt licks, wood frames, mucking boots, halters, ropes, and hay was evaluated.