Clinical and pathologic features of Mycobacterium fortuitum infections: An emerging pathogen in patients with AIDS

M. B. Smith, V. J. Schnadig, Michael Boyars, G. L. Woods

Research output: Contribution to journalArticle

48 Scopus citations


The clinical and pathologic features of Mycobacterium fortuitum infection in 11 patients with AIDS were characterized. Nine patients had cervical lymphadenitis; 2 had disseminated infection. The infection occurred late in the course of AIDS, and the only laboratory abnormality seen in more than half of patients (7/11) was relative monocytosis. Absolute monocytosis also was seen in 4 of 11 patients. In both cytologic and histologic preparations, the inflammatory pattern was suppurative with necrosis or a mixed suppurative-granulomatous reaction. M fortuitum, a thin, branching bacillus, stained inconsistently in direct smear and histologic preparations. Staining was variable with Gram, auramine, Brown-Hopps, Gram-Weigert, Kinyoun, Ziehl-Neelsen, modified Kinyoun, and Fite stains. Organisms, when present, were always seen in areas of suppurative inflammation. Incorrect presumptive diagnosis, based on misinterpretation of clinical signs and symptoms or on erroneous identification of M fortuitum bacilli as Nocardia species, led to a delay in proper therapy for 7 of 11 patients. Definitive therapy after culture identification resulted in complete resolution of infection in all patients except 1.

Original languageEnglish (US)
Pages (from-to)225-232
Number of pages8
JournalAmerican Journal of Clinical Pathology
Issue number2
StatePublished - 2001



  • AIDS
  • Lymphadenitis
  • Mycobacterium
  • Nontuberculous mycobacteria

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this