Aspergillus spp.

Aspergillus spp. are filamentous, spore (i.e., conidia) forming fungi belonging to the Trichocomaceae family. The genus Aspergillus houses many species, a few of which are well-known and considered important opportunistic pathogens in healthcare settings, such as A. fumigatus, A. niger, A. flavus, A. terreus, A. nidulans and A. clavatus ^[1]. Aspergillus fumigatus is the most common cause of invasive pulmonary infections, whereas Aspergillus flavus is more frequently associated with invasive extrapulmonary infections. Aspergillosis can arise in numerous forms, though rare, and primarily observed in immunocompromised patients. The pulmonary system and the GI tract are the primary and secondary sites of invasive aspergillosis, respectively. With intestinal aspergillosis having a mortality rate of 39%, prevention is a key factor to reducing patient harm.

Relevance of pathogen in transmission in endoscopy

• Gastroenterology: Medium to high

• Pulmonology: High

• Ear, nose, and throat: High

• Urology: High

Relevance for endoscope surveillance

• Moderate to high level concern organism

Dependent upon species, since the vast majority of species under Aspergillus are environmental in origin and often harmless to immunocompetent individuals.

Aspergillus can present as an environmental contaminant from air or water and has been identified in literature as having contaminated GI reprocessing water systems, which feed automated reprocessors (e.g. AERs/EWDs) ^[4].

Construction, landscaping, and facility renovations will disperse fungal spores into the air, which can result in persistent contamination of air circulatory systems.

Events of environmentally acquired Aspergillus being recovered in microbial surveillance can result in pseudo-outbreaks and potentially escalate into patient safety concerns.

Transmission route

The natural reservoir is soil and plant rhizospheres.

Transmission methods: Direct contact via contaminated medical instrumentation (e.g. surgical instruments, medical devices placed intravascularly or intracardially); inhalation of conidia (spores) ^[5].

Resistance to antifungals

A. fumigatus is clinically acknowledged to have the capacity to develop resistance to azole-based medications ^[5][6].

Beyond A. fumigatus, emerging science reveals that numerous other strains are also beginning to develop anti-fungal resistance ^[7].

Example: Cultivation Method

Typically, SDA (Sabouraud Dextrose Agar) or PDA (Potato Dextrose Agar) are used as the culture medium, and incubation is performed at 35–37°C or 25–30°C, depending on the target species. While many Aspergillus spp. can grow within three days, it is important to note that often fungal species may require a longer period for observational growth. Careful attention should be given to these variations in growth time, as extended growth periods are needed when compared to traditional bacterial incubation.