The bacterium Stenotrophomonas maltophilia can be associated with chronic lower airway disease in horses, reports a group of Danish researchers.

S. maltophilia is a Gram-negative bacterium that is causing disease more often in humans, particularly among the immunocompromised population, but it is only rarely reported as causing infection in animals.

The research team led by Lotte Winther, a PhD student in the Department of Large Animal Sciences, Faculty of Life Sciences at the University of Copenhagen, noted “S. maltophilia has only once been reported as an equine pathogen.”

In 2007 Winther and colleagues collected data from seven horses with respiratory infections from which S. maltophilia was cultured. In all cases chronic coughing and an exudate composed of both mucus and pus was noted in the lower trachea during endoscopic examinations. DNA testing indicated that all seven horses were infected with the same or very similar types of the bacterium, and S