Comparison of the Vitek MS and Bruker Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Systems for Identification of Rhodococcus equi and Dietzia spp.

摘要

The soil-dwelling, saprophytic actinomycete Rhodococcus equi is a multihost, facultative intracellular pathogen that causes pyogranulomatous infections in several species of domesticated animals, in particular, in young foals and pigs (1). In addition, R. equi infects humans (2). At-risk groups are immunocompromised people, such as HIV-AIDS or cancer patients, and transplant recipients. Infection with R. equi in these patients results in a granulomatous form of pneumonia whose symptoms resemble clinical and pathological signs of pulmonary tuberculosis and which has a high mortality rate. Dietzia spp. are environmental bacteria that have been associated with human infections in a small number of cases (3). The Gram morphology and colony appearance of the species of the genus Dietzia are remarkably similar to those seen with R. equi.