Aspergillus
Microbiology
De La Cruz
May 27, 2014 Aspergillus

Aspergillus is a fungus whose spores are commonly found in the environment, and can also be found in household dust, building materials and some foods. There are numerous types, but the more common ones include Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Aspergillus nidulans and Aspergillus niger. For healthy people, this does not cause harm, the immune system is able to get rid of the spores. But for people with weakened immune systems, breathing in these spores can lead to infection. Studies have shown that Invasive Aspergillosis can occur during building renovation or construction. Outbreaks of Aspergillus skin infections have been traced to contaminated biomedical devices. Aspergillosis cannot be spread from person to person or between people and animals, and because it is not a reportable infection, the exact incidence is difficult to determine.

Aspergillus mostly targets the respiratory system. Allergic bronchopulmonary aspergillosis (ABPA), is a condition where the fungus causes respiratory symptoms, such as wheezing and coughing, but does not actually invade and destroy tissues. It can affect people who are otherwise healthy, but it is most common in people with asthma or cystic fibrosis. Invasive aspergillosis generally affects people who have weakened immune systems, such as those who have had a bone marrow transplant or solid organ transplant, are on high doses of corticosteroids, those on chemotherapy, or those with HIV. It most commonly affects the lungs, but can also cause infection in many other organs and can spread throughout the body. In this condition, the fungus invades and damages tissues in the body causing fever, chest pain, coughing, shortness of breath, and Aspergilloma or “fungus ball”. It is difficult to avoid breathing in normal levels of Aspergillus spores. For the immunosuppressed or those with severe lung diseases, there are steps that can be taken to help reduce exposure; the use of a mask if unable to avoid activities that involve close contact with soil or dust such as yard work or gardening; use of HEPA filters; thorough cleaning of skin injuries with soap and water, especially if the injury has been exposed to soil or dust may prevent Aspergillosis. Healthcare providers must consider risk factors, symptoms and physical examination when diagnosing Aspergillosis. They may perform imaging tests, such as chest x-rays or CT scans. Biopsies of affected tissue or samples of respiratory secretions to be analyzed or throat culture. Other tests are available to monitor high-risk people for Invasive Aspergillosis. Aspergillosis requires treatment with antifungal medication prescribed by a doctor. Voriconazole is currently the first-line treatment for Invasive Aspergillosis. There are other medications that can be used to treat patients who cannot take, or who have not responded to Voriconazole, such as Itraconazole, lipid amphotericin formulations, Caspofungin, Micafungin, and Posaconazole. An outbreak of Aspergillus infection at a tertiary care hospital was identified among inpatients who had amputation wounds, peritonitis, allograft nephritis, or mediastinitis. During a 2-year period, 6 patients were identified, all of whom had Aspergillus species recovered from samples from normally sterile sites. All cases clustered in the operating theater during a single 12-day period. To assess operating theater air quality, particle counts were measured as surrogate markers for Aspergillus conidia. A substantial increase in the proportion of airborne particles ⩾3 µm in size (range, 3-fold to 1000-fold) was observed in many operating rooms. A confined space video camera identified moisture and contamination of insulating material in ductwork and variable airflow volume units downstream of final filters. No additional invasive Aspergillus wound infections were identified after the operating theater air-handling systems were remediated, suggesting that this unusual outbreak was due to the deterioration of insulating material in variable airflow volume units. Aspergillus targets the immunosuppressed, and therefore it is up to the nurse to educate those on prevention of exposure to the fungus. Learning about the ubiquitous nature of this microorganism will help the nurse recognize those at risk and their risk factors, signs and symptoms according to the targeted system, and providing patients with enough knowledge to identify hazardous situations. Providing education helps to empower patients with their health. Recognizing and reporting symptoms immediately will be life saving for those at risk.

References:

"Aspergillosis." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 13 Feb. 2014. Web. 25 May 2014. .

Brock D. Lutz, Jiankang Jin, Michael G. Rinaldi, Brian L. Wickes, and Mark M. Huycke, Outbreak of Invasive Aspergillus Infection in Surgical Patients, Associated with a Contaminated Air-Handling System. Clin Infect Dis. (2003) 37 (6): 786-793 doi:10.1086/377537

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