Macrolide- and rifampin-resistant rhodococcus equi on a horse breeding farm, Kentucky, USA

Abstract

Macrolide and rifampin resistance developed on a horse breeding farm after widespread use was instituted for treatment of subclinical pulmonary lesions in foals. Resistance occurred in 6 (24%) of 25 pretreatment and 8 (62%) of 13 (62%) posttreatment isolates from affected foals. Drugresistant isolates formed 2 distinct genotypic clusters.