A pseudo‐outbreak of Rhinocladiella similis in a bronchoscopy unit of a tertiary care teaching hospital in London, United Kingdom

Abstract

Outbreaks of fungal infections due to emerging and rare species are increasingly reported in healthcare settings. We investigated a pseudo‐outbreak of Rhinocladiella similis in a bronchoscopy unit of a tertiary care teaching hospital in London, UK. We aimed to determine route of healthcare‐associated transmission and prevent additional infections. From July 2018 through February 2019, we detected a pseudo‐outbreak of R. similis isolated from bronchoalveolar lavage (BAL) fluid samples collected from nine patients who had undergone bronchoscopy in a multispecialty teaching hospital, during a period of 8 months. Isolates were identified by MALDI‐TOF mass spectrometry. Antifungal susceptibility testing was performed by EUCAST broth microdilution. To determine genetic relatedness among R. similis isolates, we undertook amplified fragment length polymorphism analysis. To determine the potential source of contamination, an epidemiological investigation was carried out. We reviewed patient records retrospectively and audited steps taken during bronchoscopy as well as the subsequent cleaning and decontamination procedures. Fungal cultures were performed on samples collected from bronchoscopes and automated endoscope washer‐disinfector systems. No patient was found to have an infection due to R. similis either before or after bronchoscopy. One bronchoscope was identified to be used among all affected patients with positive fungal cultures. Physical damage was found in the index bronchoscope; however, no fungus was recovered after sampling of the affected scope or the rinse water of automated endoscope washer‐disinfectors. Use of the scope was halted, and, during the following 12‐month period, Rhinocladiella species were not isolated from any BAL specimen. All pseudo‐outbreak isolates were identified as R. similis with high genetic relatedness (>90% similarity) on ALFP analysis. The study emphasises the emergence of a rare and uncommon black yeast R. similis, with reduced susceptibility to echinocandins, in a bronchoscope‐related pseudo‐outbreak with a potential water‐related reservoir. Our findings highlight the importance of prolonged fungal culture and species‐level identification of melanised yeasts isolated from bronchoscopy samples. Possibility of healthcare‐associated transmission should be considered when R. similis is involved in clinical microbiology samples.

Hydrocarbon-Contaminated Sites: Is There Something More Than Exophiala xenobiotica? New Insights into Black Fungal Diversity Using the Long Cold Incubation Method

“…Several members of the genus Exophiala are potential agents of human and animal mycoses and for that are considered to be in the Bio Safety Level-2 (BSL-2) group. In this study, together with E. xenobiotica, we found other species associated with clinical cases, including E. oligosperma a sporadic agent of phaeohyphomycosis [81,82], E. phaeomuriformis mentioned in relation to keratitis [83], Rhinocladiella similis recently found in a nosocomial infection [84], and Knufia epidermidis associated with mild skin infections [85].…”

The Consequences of Our Changing Environment on Life Threatening and Debilitating Fungal Diseases in Humans

“…An increased number of fungal species more typically associated with plant pathogenesis are now seen as causative agents of keratitis [ 148 , 149 ]. Fungal outbreaks caused by emergent and rare species are still being recognised in previously unknown patient cohorts [ 150 , 151 ]. Again further work needs to be undertaken to differentiate improvements in diagnosis from increases in infection rates linked directly to climate change.…”

Bronchoscopy-related outbreaks and pseudo-outbreaks: A systematic review

“…Among the isolated organisms, Rhodotorula rubra was identified in 3 studies, whereas all other species were reported in only 1 study each. 26,62,87 These included Fusarium solani , 17 Rhinocladiella similis , 58 Phaeoacremonium parasiticum , 19 Aureobasidium spp. 88 In 1 study, both Trichosporon cutaneum and Penicillium spp were isolated.…”

“…In 24 studies, the source of contamination was attributed to a defect in the bronchoscope itself. 7,12,16,43,46,[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] Bronchoscope segments identified as being defective or damaged included the lumen, the suction valve and channel, the biopsy port and its cap, as well as the biopsy channel itself. Notably, in 1 study the defect at the entry port of the biopsy channel was so significant that it led to a recall of the specific model by the manufacturer.…”