A 29-year-old female with a past medical history of polysubstance abuse (methamphetamine/heroin), chronic hepatitis C, and seizures presented to the emergency room in September 2019, with a complaint of full body aches, fever, chills, diffuse chest pain, shortness of breath, and yellow to bloody sputum production for 3 days before admission. Three weeks prior to presentation, she had a cardiorespiratory arrest after a heroin overdose and required cardiopulmonary resuscitation with chest compressions. She was previously in drug use (naltrexone) remission which was discontinued due to elevated liver enzymes. The last time she used methamphetamine was 3 days prior to admission, without having withdrawal symptoms. She used sterile needles obtained from an exchange clinic, did not share or lick them but admitted sharing the water used to mix drugs. Her lactic acid levels were moderately elevated (2.17 mmol/L) but her other lab work-ups including the WBC count, were normal. A trans-esophageal echocardiogram was negative for vegetation. Chest X-ray and computerized tomography (CT) scan of the chest (Figure 1) confirmed multifocal pneumonia. The chest CT (Figure 1A) showed bilateral airspace opacities throughout the right upper, middle, and lower lobes, including the lingula. No cavitation or pleural effusions were seen to suggest septic emboli. Mediastinal and hilar structures demonstrated no filling defects within the pulmonary arteries to suggest pulmonary emboli. Patient vitals remained stable.
Two sets of blood cultures were collected and incubated at 35 C in the BACTEC FX system (Becton Dickinson, Sparks Maryland) and the patient was started on vancomycin (1500 mg, intravenous (IV), every 12 hours) plus piperacillin/tazobactam (3.375 g, IV, every 8 h). Despite antimicrobial therapy, she continued complaining of diffuse chest pain and cough. The second blood culture became positive at 3 days of incubation. The blood culture was sub-cultured onto blood, potato flake, Sabouraud's, CHROMagar, and corn meal agar plates and incubated at 30 C. Azithromycin (500 mg, IV, every 24 hours) and micafungin (100 mg, IV, every 24 hours) were added to the therapeutic regimen. A wet preparation showed narrow-necked budding yeast-like fungus (Figure 2A) primarily consisting of round to oval cells, and the Gram stain revealed budding yeast-like cells (Figure 2B). Growth was observed after 24 to 48 hours of incubation on all agar mediums and characterized as smooth, pin-point small white colonies (Figure 2C and D). Appearance on CHROMagar did not identify any Candida species while morphological assessment on corn meal agar was suggestive of a yeast-like fungus predominately, round to oval in appearance. Matrix-assisted laser desorption/ionization:time of flight (MALDI-TOF) mass spectrometry analysis (Bruker Daltonic, Billierica, MA, USA using Bruker flexAnalysis and flexControl software version 3.4), performed 3 independent times, failed to identify the organism. Yeast within the genus Candida and, Cryptococcus due to the observation of narrow neck budding, were in the differential but was pending confirmation. Symptoms subsided after antifungal administration and a chest X-ray showed relative improvement. Additional tests (HIV, TB, and Legionella) were unremarkable. The sputum culture was predominately indigenous oral flora.
The yeast-like colonies were sent for molecular testing (ARUP Laboratories, Salt Lake City, Utah). The rDNA sequencing, targeting the ITS1 (internal transcribed spacer 1) region, identified the organism as Sporopachydermia lactativora (NCBI #, AF202900.1 (%ID = 100%; hits (444/444)). Antifungal susceptibility testing (YeastOne, Sensititre, Thermo Fisher) was performed and MIC values were provided to the treating clinician with no interpretations for sensitivity or resistance, as there are no interpretive criteria for this species.   The reported antifungal MIC values for this species were as follows: Micafungin (8 mug/mL), AmphotericinB (0.5 mug/mL), Itraconazole (0.06 mug/mL), Anidulafungin (2 mug/mL), Capsofungin (4 mug/mL), Fluconazole (<=0.12 mug/mL), Flucytosine (<=0.06 mug/mL), Posaconazole (0.06 mug/mL), and Voriconazole (<=0.008 mug/mL). The patient continued on intravenous micafungin (100 mg, IV, every 24 hours) for the duration of her hospital stay. Her clinical condition improved and she was discharged 13 days after admission, with micafungin (100 mg, IV, every 24 hours) as part of her continuing treatment. Micafungin was discontinued when she showed no further respiratory symptoms on her follow-up visit (11 days after her discharge). Her lungs were clear on auscultation.