Microbiology Case Study: A 59 Year Old Male with Acute Prostatitis

Clinical history

A 59 year old male with a past medical history of benign prostatic hypertrophy who presented to his primary care physician with complaints of dysuria, urgency, nocturia, and a weak stream. He was referred to a urologist who diagnosed him with acute prostatitis. The patient was given Flomax, a medication that relaxes the muscles in the prostate and bladder, and sulfamethoxazole-trimethoprim, an antibiotic for his possible bladder infection. The patient continued to have urinary symptoms despite antibiotics and multiple urinary cultures that were negative for growth of bacteria. Eventually the patient’s symptoms worsened and he presented to the emergency department with symptoms of fever (102.8ºF), bladder spasms, drenching night sweats, and painful urinary retention. His lab results showed a mild leukocytosis (15,500 cells /mm3) and increased leukocyte esterase, leukocytes, and erythrocytes in his urine. He was admitted and a pelvic computed tomography scan showed multiple prostatic abscesses. The infectious disease team ordered a urine fungal culture. The fungal stain showed broad-budding yeast forms (Image 1).

Image 1. Calcofluor white fungal stain highlighting brad-based budding yeast (100x oil immersion).

Laboratory identification

A cytospin Gram stain was made of the urine specimen which showed rare large yeast forms, numerous red blood cells and neutrophils (Image 2). These yeast forms are consistent with Blastomyces dermatitidis which are 10-15 µm in diameter and have thick contoured cell walls. The fungal culture grew a dirty white leathery mold on inhibitory mold agar after ten days. The lactophenol cotton blue adhesive tape preparation highlighted short to long conidiophores with large pear-shaped conidia at the tips of delicate conidiophores and septated hyphae. A positive urine antigen test supports the identification of the organism as Blastomyces dermatitidis.

Image 2. Large yeast with thick refractile walls seen on Gram stain. Flattened areas suggest recent separation.

Discussion

Blastomyces dermatitidis is a dimorphic fungus commonly found in the eastern half of the United States and Canada, specifically the Mississippi and Ohio River valleys, and Great Lakes Region. It typically grows as a mold in damp soil and decomposing vegetation; outdoor activities that disrupt the soil can increase the risk of infection. Infection occurs when the reproductive spores known as conidia are inhaled into the alveoli of the lungs. There the conidia transform into yeast and multiply causing the disease blastomycosis. Approximately 50% of those infected with Blastomyces are asymptomatic and clear the infection without trouble. For the other 50%, symptoms depend on the course of infection with a range of flu-like illness over a few days to chronic or severe illness that can last for months. Symptoms include fever, chills, headache, joint and muscle pains, shortness of breath, cough, night sweats, weight loss, and pleuritic chest pain. Twenty to forty percent of symptomatic patients will have disseminated disease. The common extra-pulmonary sites include skin, bone, urogenital, and the central nervous system, however, it has been reported in all organ systems.

In our case, the patient presented with prostatic blastomycosis which was quickly identified by calcofluor white fungal stain and urine antigen test. The patient was placed on itraconazole and a transurethral prostatic resection was performed. Histopathologic analysis showed necrotizing granulomas with fungal elements that are consistent with Blastomyces dermatitidis (Image 3). After a few days of treatment, the patient was discharged and is being followed on an outpatient basis.

Image 3. PAS stained tissue showing three budding yeast forms in a granuloma with extensive neutrophilic reaction.

– Joshua Wodskow, DO is a 1st year clinical and anatomic pathology resident at University of Chicago (NorthShore). Academically, Joshua has a particular interest in hematopathology and informatics. In his spare time, Joshua enjoys board games with his family and listening to podcasts.

-Erin McElvania, PhD, D(ABMM), is the Director of Clinical Microbiology NorthShore University Health System in Evanston, Illinois. Follow Dr. McElvania on twitter @E-McElvania. 

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