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

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.

Clinical presentation of HIV infection in patients aged 50 years or older

OBJECTIVES

To describe the clinical presentation of HIV disease in older patients.

METHODS

In the period 1989-1996 we reviewed the medical records of 100 patients with human immunodeficiency virus (HIV) infection aged 50 years or older and, 197 controls among HIV-infected patients aged 15-40 years, who attended six institutions in the autonomous community of Valencia (Spain).

RESULTS

Older patients were mostly males (86%), men who have sex with men (42%) or unknown (20%) as exposure categories. Older patients had lower CD4 cell counts/mm3 (163+/-136 vs. 450+/-373, P= 0.008), and had AIDS at first evaluation (49% vs. 29%, P = 0.0006) compared with younger patients. For patients presenting with AIDS at HIV infection diagnosis, type and frequency of AIDS indicator diseases did not differ between older and younger patients.

CONCLUSION

Studies on clues for early detection of HIV infection in patients aged 50 years or older are urgently needed to improve the health care in this population.

Endocarditis caused by Stenotrophomonas maltophilia: case report and review

Stenotrophomonas (Xanthomonas) maltophilia is a rare cause of endocarditis. The extensive resistance of this organism to several antibiotics leaves few options for antimicrobial therapy. In vitro synergism of the combination of trimethoprim-sulfamethoxazole (TMP-SMZ) and ticarcillin/clavulanic acid (TIC/CA) has been demonstrated. To our knowledge, we report the first case of ventriculoatrial cerebrospinal fluid shunt-associated endocarditis due to S. maltophilia. The patient was cured with combination therapy with TMP-SMZ and TIC/CA along with catheter removal. This is also the first report of S. maltophilia endocarditis successfully treated with this antibiotic combination. In a review of the medical literature, only 16 cases of S. maltophilia endocarditis were found. Most patients were intravenous drug users (43.8%) or had either prosthetic heart valves (50%) or an indwelling vascular catheter (18.8%). Although S. maltophilia is usually considered a nosocomial pathogen, about one-half of the cases were community-acquired. Twelve of sixteen patients had left-sided endocarditis. Therapy with a combination of two or more antibiotics was employed in most cases. Seven patients had been given TMP-SMZ therapy, but none had been treated with TIC/CA before. One-half of the patients required cardiac surgery. The overall mortality rate was 33%. Although the optimal antibiotic treatment for S. maltophilia endocarditis remains unknown, the case reported herein reinforces in vitro findings that the combination of TMP-SMZ and TIC/CA may be effective therapy.