Rhodococcus equi infection in a dairy goat from a herd in northeastern Italy

A 3-year-old Chamois Colored dairy goat from a herd in Treviso province (northeastern Italy) was examined for progressive weight loss and enlargement of cervical lymph nodes. The general condition rapidly worsened to severe weakness and death within few days. Multiple nodular caseous pyogranulomas were found in the lymph nodes, lung, liver, and spleen. Numerous intracytoplasmic Gram-positive coccobacilli were found within macrophages and neutrophils. Aerobic bacterial cultures yielded pure cultures of Rhodococcus equi, identified with MALDI-TOF mass spectrometry and 16S rDNA sequencing. The isolated strain resulted resistant to trimethoprim/sulfamethoxazole and susceptible to tetracycline (MIC values for horses). Other infectious diseases including Mycobacterium spp., small ruminant lentiviruses (SRLV), and pestiviruses were excluded. In recent years, several reports have described Rhodococcus equi infections in ruminants worldwide, especially after the recognition of the ruminant-associated virulence plasmid VapN. Rhodococcus equi might represent an unrecognized pathogen in goats that should be considered in the differential diagnosis of caprine tuberculosis and pseudotuberculosis, also in view of its zoonotic potential.