Corynebacterium pseudodiphtheriticum: An easily missed respiratory pathogen in HIV-infected patients

Despite being a well-known respiratory pathogen for immuno-compromised pati ents, Corynebacterium pseudodiphtheriticum has uncommonly been reported to occur in persons with infection attributable to HIV virus. We report three cases of respiratory tract infection attributable to C. pseudodiphtheriticu m in HIV-infected patients and review the four previous cases from the medi cal literature. All of them were male with a median CD4 lymphocyte count of 110 cells/mm(3) (range, 18-198/mm(3)); five of the seven cases occurred in persons for whom AIDS was diagnosed previously. The onset of symptom atolo gy was usually acute and the most common radiographic appearance was alveol ar infiltrate (six patients) with cavitation (two patients) and pleural eff usion (two patients). In five of the seven cases, C. pseudodiphtheriticum w as isolated from bronchoscopic samples and in the remaining two cases was r ecovered from lung biopsy (one patient) and sputum (one patient). In the th ree patients reported herein and in one previous case from the medical lite rature, quantitative culturing of bronchoscopic samples obtained through ei ther bronchoalveolar lavage or protected brush catheter procedures yielded more than 10(3) CFU/mL. All the strains tested were susceptible to penicill in and vancomycin. Resistance to macrolides was common. Recovery was observ ed in six of the seven patients. C. pseudodiphtheriticum should be regarded as a potential respiratory pathogen in HIV-infected patients. This infecti on presents late in the course of HIV disease and it seems to respond well to appropriate antibiotic treatment in most of the cases. This easily overl ooked pathogen should be added to the list of organisms implicated in respi ratory tract infections in this population. (C) 1999 Elsevier Science Inc.