Publications IPH Magazine IPH Magazine #16 Risk of infections caused by the presence of the fungus Aspergillus.sp: remodeling hospitals and climatization systems

1. Introduction

2. Treatment and indoor air quality at healthcare facilities as an element of healing

The importance of conducting a microbiological assessment of the ambient air is justified due to the outbreaks of fungal and bacterial infections often associated with construction sites and remodeling in hospitals. A study carried out by VONBERG & GASTMEIER (2006) investigated 53 outbreaks caused by invasive Aspergillosis infection and found that 49.1% of probable or possible cases of Aspergillus spp. were related to construction and remodeling in hospitals, and 17% were related to refrigeration problems. The most common source of transmission was the air, and the lower respiratory tract was the main site of infection, followed by surgical and skin wound infections.

Frare (2009) adds to the aforementioned statement when it makes a reference to Frech (2005), describing an increase in cases of Aspergilose among immunosuppressed patients during remodeling processes within the hospital areas besides the non-reliable maintenance of air filter. He emphasizes then the importance of having total integration in the work and communication processes between the commissions that control nosocomial infections and the engineer areas, aiming at the prevention against such infections and avoiding outbreaks in hospitals.

Karman (2011) points out that Aspergillus fungus, with an average diameter of 2 to 3.5 µm, including its spore, is resistant to dehydration and may remain suspended in the air indefinitely if associated with dust and moisture.

Picture 1 - Aspergillus

Credit: Mogana Das Murtey and Patchamuthu Ramasamy [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)

The modern technologies for climatization systems can improve indoor air quality, since it is possible to design suitable filtration and temperature control systems, which you can regulate to meet various specific conditions. However, they should be employed with full awareness of the adverse impacts on human health. Although filters remove unwanted particles and breathable particles from outdoor air, they enable an environment that helps develop a multitude of bacteria and other infectious agents. As a result, it is necessary to estimate the costs for the maintenance of the building to monitor and replace filters regularly (STERLING; COLLET; RUMEL, 1991).

Among the various diseases caused by fungi and bacteria that spread through air conditioning systems in hospitals and health facilities, the Aspergillus is one of the main agents responsible for fungal infections, presenting high mortality rates, between 68% and 95% (FRARE, 2009). As Bernal (2015) said:

Aspergillus spp. is an opportunistic saprophyte widely spread across nature. It can cause a wide range of diseases, from allergies to invasive infections in humans. Invasive Aspergillosis (AI) is the most serious infection caused by Aspergillus spp. It affects mainly the lungs of immunosuppressed patients and may spread to deep organs. (BERNAL, 2015, p. 315).

Aspergillosis is one of the most recurrent fungal infections in immunosuppressed patients, besides being the main cause of death among such patients. They get the disease after inhaling: fungal spores found in hospital ventilation systems; air contaminated by construction sites and remodeling; dust and contaminated materials. Units treating cancer and transplants, especially those without air filtration and air renewal systems, are considered high-risk environments for Aspergillosis outbreaks (FRARE, 2009).

3. Testing the quality of the air inside the ICU of a specialized high-complexity hospital

To test the presence of Aspergillus fungus in the sector, we will present the results from microbiological tests of air harvested in the ICU common treatment area at a public, state-managed, medium-sized specialized high-complexity hospital, located in the city of São Paulo.

The ICU of this hospital was remodeled in the first half of 2017, the process was completed in July of the same year. For the research, we have strategically chosen three samples of air: the first one from December 2016, under normal conditions, before remodeling had begun; the second, shortly after the work had finished, in August 2017; and the last one in November. In August, the thin and absolute filters were replaced in the air conditioning system that supplies to the building. The entire system receives preventive and corrective maintenance regularly, when required, which is overseen by a professional mechanical engineer. Prior to remodeling, an essential and contingent plan was prepared with the Institution, aiming at impacting as little as possible patients and other departments in the hospital. 

Pictures 2 and 3 - Replacing F7 saturated bag filters, August 2017

Credit: Personal collection.

The analysis concerning the quality of indoor air were carried out following the recommendations put forward by the Brazilian Association of Technical Standards (ABNT) ISO/IEC 17025, NBR 10719 and by Ruling - RE n. 09, from MS/ANVISA, on 16 January 2003. Based on the regulatory standards, here there are the results obtained from our three tests:

Table 1 - Technical Standard #1

Source: Indoor air quality report after testing. Personal collection. 

Table 2 - Technical Standard #2 and #3

Source: Indoor air quality report after testing. Personal collection.

Table 3 - Technical Standard #4

Source: Indoor air quality report after testing. Personal collection.

Regarding the aforementioned Technical Standards, all results are within acceptable levels from a quantitative standpoint. On the other hand, from a qualitative viewpoint, Table 1 indicates the presence of fungus Aspergillus in the environment almost at the same time the works were being carried out.

As a consequence, and based on theory, it is possible to verify the presence of this microorganism is directly related to the intervention period, corroborating what Karman states (2011, p. 151):

The rowdiness caused by construction and remodeling works, especially in healthcare facilities, can release dust with airborne spores of Aspergillus fungi, which are potentially lethal for immunosuppressed patients. The Aspergillus fungus, which is 2 to 3.5 µm (diameter), is found on the soil, at moist environments and in rotting vegetables. It can also be found in ventilation systems that are not operating properly: air filters, window air conditioners, suction fans, false ceilings, acoustic ceilings, construction sites, exposed doors or windows, hospital vacuum cleaners, ornamental plants, pigeons etc. The dust from neighboring work sites can also affect healthcare facilities since the Aspergillus is sporulated and airborne (airborne bacterium). The humidity of an environment also contributes to its proliferation. Thus, equipment and instruments colonized with the fungus, when stored in humid environments, might become a source of infection.