Isolation of opportunistic fungi from bronchoalveolar lavage of compromised hosts in Isfahan, Iran

Community-acquired bacteremic Streptomyces atratus pneumonia in animmunocompetent adult: a case report

INTRODUCTION

Streptomyces spp. are aerobic, Gram-positive bacteria of the order Actinomycetales, known for their ability to produce antimicrobial molecules such as streptomycin. Pneumonia due to Streptomyces is considered to be rare and limited to immunocompromised patients. Streptomyces spp. are only rarely associated with invasive systemic infections. To our knowledge, we report the first documented case of community-acquired Streptomyces atratus bacteremic pneumonia in an immunocompetent patient.

CASE PRESENTATION

We describe a case of Streptomyces atratus bacteremic pneumonia in an otherwise healthy, 77-year-old Spanish man. Streptomyces identified by 16S ribosomal RNA sequencing grew in multiple blood cultures and bronchoalveolar lavage cultures. The infection resolved completely after treatment with imipenem and amoxicillin/clavulanic acid for 2 months.

CONCLUSIONS

The majority of cases reported in the literature make reference to the difficulty of determining the pathogenic role of Streptomyces spp. Usually considered a contaminant, the pathogenic role of Streptomyces spp. is easier to confirm when the species is isolated from a catheter tip and, in the case of blood cultures, in more than one sample with a high count of colonies. To our knowledge, we report the first documented case of Streptomyces atratus bacteremic pneumonia in an immunocompetent patient. As the experience is limited, further studies are needed to better understand the interpretation of the isolates of the genus Streptomyces; the predisposing factors for infection; and the course, treatment, and evolution of these infections.

The incidence of opportunistic fungi in patients suspected of tuberculosis

The incidence of opportunistic fungi in bronchoalveolar lavage specimens from patients suspected of tuberculosis in Isfahan, Iran, was determined. From 200 patients 36 yeasts (18%) and seven filamentous fungi (3.5%) were isolated. Out of 44 patients who had fungal infections, 12 cases were affected with definite tuberculosis.

Aspergillus nidulans infection in chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare inherited disorder of the NADPH oxidase complex in which phagocytes are defective in generating reactive oxidants. As a result, patients with CGD suffer from recurrent bacterial and fungal infections. The most common fungal infections are caused by Aspergillus species. Aspergillus nidulans is a rare pathogen in most patient populations with quantitative or qualitative neutrophil defects. We have reviewed all cases in which A. nidulans was isolated from patients at the National Institutes of Health (Bethesda, MD) between 1976 and 1997. A. nidulans infection occurred in 6 patients with CGD, but was not a pathogen in any other patient group. Aspergillus fumigatus was a more common pathogen in CGD compared with A. nidulans, but A. nidulans was more virulent. A. nidulans was significantly more likely to result in death compared with A. fumigatus, to involve adjacent bone, and to cause disseminated disease. Patients with A. nidulans received longer courses of amphotericin B therapy than patients with A. fumigatus, and were treated with surgery more often. In contrast to A. fumigatus, A. nidulans was generally refractory to intensive antifungal therapy, suggesting that early surgery may be important. These data show that A. nidulans is a distinct pathogen in CGD and its isolation carries more severe implications than that of A. fumigatus.