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Corynebacterium pseudodiphtheriticum: an easily missed respiratory pathogen in HIV-infected patients
F Gutiérrez-Rodero1, V Ortiz de la Tabla, C Martínez
1Servicio de Medicina Interna, Hospital General Universitario de Elche, Alicante, Spain.
Abstract:
Despite being a well-known respiratory pathogen for immunocompromised patients, 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. pseudodiphtheriticum in HIV-infected patients and review the four previous cases from the medical literature. All of them were male with a median CD4 lymphocyte count of 110 cells/mm3 (range, 18-198/mm3); five of the seven cases occurred in persons for whom AIDS was diagnosed previously. The onset of symptomatology was usually acute and the most common radiographic appearance was alveolar infiltrate (six patients) with cavitation (two patients) and pleural effusion (two patients). In five of the seven cases, C. pseudodiphtheriticum was isolated from bronchoscopic samples and in the remaining two cases was recovered from lung biopsy (one patient) and sputum (one patient). In the three patients reported herein and in one previous case from the medical literature, quantitative culturing of bronchoscopic samples obtained through either bronchoalveolar lavage or protected brush catheter procedures yielded more than 10(3) CFU/mL. All the strains tested were susceptible to penicillin and vancomycin. Resistance to macrolides was common. Recovery was observed in six of the seven patients. C. pseudodiphtheriticum should be regarded as a potential respiratory pathogen in HIV-infected patients. This infection 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 overlooked pathogen should be added to the list of organisms implicated in respiratory tract infections in this population.
Insights
Corynebacterium pseudodiphtheriticum is an uncommon respiratory pathogen in individuals with human immunodeficiency virus (HIV) infection. This bacterium can cause severe lung infections, particularly in advanced stages of HIV disease, but typically responds to antibiotic therapy.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Pulmonology
Background:
- Corynebacterium pseudodiphtheriticum is a known respiratory pathogen, primarily affecting immunocompromised individuals.
- Infections caused by C. pseudodiphtheriticum in patients with human immunodeficiency virus (HIV) are rarely documented.
Observation:
- This study reports three new cases of C. pseudodiphtheriticum respiratory tract infections in HIV-positive patients, alongside a review of four previously reported cases.
- The seven patients were predominantly male, with a median CD4 lymphocyte count of 110 cells/mm³, and five had a prior AIDS diagnosis.
- Common clinical presentations included acute onset, alveolar infiltrates on chest imaging, with some cases showing cavitation or pleural effusion.
Findings:
- C. pseudodiphtheriticum was isolated from bronchoscopic samples in most cases (five of seven).
- Quantitative cultures from bronchoalveolar lavage or protected brush catheter procedures yielded >10³ CFU/mL in four cases.
- All tested strains were susceptible to penicillin and vancomycin, but resistance to macrolides was frequent. Six of seven patients recovered.
Implications:
- C. pseudodiphtheriticum should be considered a potential respiratory pathogen in HIV-infected patients, especially those with advanced disease.
- The pathogen often presents late in HIV disease progression.
- Prompt diagnosis and appropriate antibiotic treatment, such as with penicillin or vancomycin, are crucial for favorable outcomes.