Complicated nocardiosis successfully treated with trimethoprim and sulphamethoxazole

Nocardia species: host-parasite relationships

The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated.

Synergistic action of trimethoprim and sulfamethoxazole for Nocardia asteroides: efficacious therapy in five patients

Eighteen isolates of Nocardia asteroides were tested for in vitro susceptibility to trimethoprim (TMP) and sulfamethoxazole (SMZ) alone and in various combinations using disc and paper strip diffusion tests. TMP-SMZ showed synergistic action for two-thirds of teh nocardia isolates tested. Five patients with Nocardia pneumonia were treated with TMP-SMZ and all were cured. Four of the patients' isolates were tested and all showed synergistic patterns of inhibition with the spaced disc and paper strip methods. The agar diffusion disc and synergy tests of TMP-SMZ appear to correlate with clinical usefulness when the Nocardia are susceptible with large zones of inhibition around the combination TMP-SMZ disc.

Peritoneal nocardiosis: report of a case

A case of primary peritoneal nocardiosis is presented. The patient died, despite prompt, aggressive and appropriate antibiotic therapy. Decreased patient resistance is suggested as the cause of the overwhelming nature of the infection in this case. The importance of administering prophylactic antibiotics on a long-term basis to prevent recurrence after successful treatment is stressed. Although nocardial infections are rare, they may become more common because of the current widespread use of immunosuppressive therapy.

Nocardia asteroides primary cerebral abscess and secondary meningitis

A rare case of primary cerebral abscess due to Nocardia asteroides, and its surgical removal, are described. Postoperative meningitis caused by the same fungi was succesfully cured with sulphadiazine and cycloserine. The nocardial disease, its neurological complications, and therapy are reviewed.