Nocardia species: host-parasite relationships.

Abstract

From the very beginning, there has been uncertainty over the taxonomic position of nocardioforms, i.e., bacteria that resemble Nocardia organisms. The specific taxonomy of isolates of this heterogenous group of organisms is still in flux and controversial (275, 278, 403, 404, 420, 584, 676, 699). During the ensuing 100 years, it has been shown that N. asteroides is a heterogeneous taxon (275, 403, 404, 420). It is not within the scope of this review to address this complex subject, yet it is important to note that N. asteroides, as currently defined, probably consists of several subtypes and/or species. These include N. asteroides sensu stricto, N. farcinica, N. nova, and several distinct serotypes and biotypes (278, 403, 404, 698, 699, 727). Regardless of their designation, all of these varieties of the N. asteroides taxon have been isolated from humans and animals with serious (often fatal) infections (93, 584, 698, 699). The other pathogenic Nocardia species appear to be taxonomically more homogeneous and include N. brasiliensis, N. otitidiscaviarum (N. caviae), and N. transvalensis (275, 420). There is even one Nocardia species that infects plants: N. vaccinii, which causes galls on blueberry plants (420).

Isolation of both Pseudozyma aphidis and Nocardia otitidiscaviarum from a mycetoma on the leg

“…There are four clinical types of cutaneous nocardiosis: mycetoma, lymphocutaneous infection, suppurative skin infection, and secondary cutaneous infection with disseminated disease. 5 Mycetoma is a late-stage infection as in the case presented here. Nocardia otitidiscaviarum is less pathogenic than other species of Nocardia, being responsible for 2.9% of cases of infections due to Nocardia in the United States.…”

IgM but not IgG monoclonal anti-Nocardia brasiliensisantibodies confer protection against experimental actinomycetoma in BALB/c mice

“…Human infection caused by N. brasiliensis occurs in immunocompetent individuals (Salinas-Carmona, 2000) with intact cell-mediated responses that fail to clear this intracellular bacterium, resulting in its chronic persistence within infected cells (Folb et al, 1976;Beaman & Beaman, 1994). Antibody-mediated protection against intracellular pathogens is of remarkable concern, and has been reviewed by several authors (Teitelbaum et al, 1998;Casadevall, 2003Casadevall, , 2004de Vallière et al, 2005).…”

Successful Treatment of Disseminated Nocardiosis Caused by Nocardia veterana in a Dog

“…In people with disseminated nocardiosis, approximately 65% have underlying immunodeficiency, so it may be more likely in this case that combination immunosuppressive drug treatment was responsible. 22 In addition, the dog was clinically stable for 3 months after initiation of immunosuppressive drug treatment, so it seemed unlikely that nocardiosis contributed to the clinical signs of IMPA. However, after treatment for Nocardia and discontinuation of immunosuppressive drug treatment, there has been no relapse in clinical signs for IMPA.…”