Rhinocladiella mackenziei

Rhinocladiella mackenziei is a pigmented fungus.

Primary cerebral phaeohyphomycosis due to Rhinocladiella mackenziei is an extremely rare infection carrying more than 80% mortality, with most cases reported from the Middle East region. This darkly pigmented black yeast is highly neurotropic, aggressive and refractory to most antifungal agents.

Cerebral abscess due to pigmented moulds are a rare but usually fatal infection occasionally seen in transplant recipients.

Rhinocladiella mackenziei was believed to be endemic solely to the Middle East, due to the first cases of infection being limited to the region. However, cases of R. mackenziei infection are increasingly reported from regions outside the Middle East. The agent is dissimilar to typically opportunistic agents of fungal disease in that the majority of cases have been reported from immunologically normal people.

A 67 year old male of Iraqi origin underwent a deceased donation renal transplant for renal failure and 2 months later was diagnosed with an abscess in the left posterior frontal lobe of his brain. Subsequent biopsy proved this to be due to the mould Rhinocladiella mackenziei. Further interventions included two operations to aspirate the lesion, voriconazole, then liposomal amphotericin B, then a combination of posaconazole and flucytosine which he continued for over four years. He also suffered from right ankle pain and was diagnosed with septic arthritis; R. mackenziei was isolated from pus aspirated from the ankle joint. He responded well to the treatment and has had little loss of function, and on CT the cerebral lesion has stabilised. Beta-D-glucan, initially at very high levels proved useful to monitor response over the 5 years and the latest sample was negative (38 pg/mL). This case is notable for the first disseminated case of this infection, its favourable outcome on a novel antifungal combination and a new approach to monitoring the course of disease ¹⁾.

Barde et al. analyzed posaconazole concentrations in plasma and multiple CNS specimens taken from a patient who received posaconazole because of cerebral phaeohyphomycosis. Low posaconazole concentrations were obtained in CNS specimens, with sample-to-plasma ratios between 5% and 22%. This case highlights the role of neurosurgery during cerebral phaeohyphomycoses, even those caused by posaconazole-susceptible black fungi. ²⁾.

Yusupov et al. presented an immunocompetent elderly male, presenting with multiple brain abscesses, with R. mackenziei confirmed by nuclear ribosomal repeat region sequencing, who was successfully treated by surgical debridement and intravenous voriconazole. To our knowledge this is the first case reported from the United Kingdom. We also present a review of all such cases so far reported in the English literature world-wide, which we believe is a step further to understanding the pathogenesis and establishing effective treatment of this rare, yet often fatal disease ³⁾.

Cristini et al. described the case of a native Afghan woman living in France who presented with brain abscesses due to R. mackenziei ⁴⁾.