Isolation of Fungi in Indoor Air Environment of Selected Air-Conditioned and Non- Air-Conditioned Wards in a Public Tertiary Hospital in Metro Manila, Philippines

Ferissa B. Ablola, Alice Alma C. Bungay

Abstract


Background and Objectives: Hospital as health care facility has also become a source of infection that provides niche to different microbiological agents such as fungi. Exposure to these organisms are specifically detrimental to highly immunocompromised in-house patients. This present study would like to 1) detect the presence of fungi in a public tertiary hospital in Metro Manila, 2) determine the dominating fungal organism and 3) describe the environmental conditions and physical factors affecting the proliferation of fungal organisms.

Methodology: Eight sampling sites were selected for this study. Hospital Main Lobby was the comparison site for the three non-air-conditioned surgery wards (NACWs) while the fourth level nurse station is the comparison site for the air-conditioned wards (ACWs). Meteorologic conditions such as environmental temperature and relative humidity were also determined. Andersen air sampler was utilized to conduct the environmental indoor air sampling. A total of 98 malt extract agar supplemented with chloramphenicol (0.01%) plates were utilized for the duplicate sampling in eight sites. After three to five days of incubation at 37° C, the isolated fungal organisms were culturally and morphologically characterized.

Results: Seven fungal organisms were isolated from the indoor air sampling conducted namely: Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Curvularia sp., Penicillium sp., Alternaria sp. and Rhizopus sp.). The most dominant fungal species among the NACWs was A. niger. On the other hand, A. fumigatus was the most observed isolate among ACWs. Evidently, the air-conditioned wards showed higher number of fungal isolates. In particular, A. fumigatus and A. flavus colonies in ACWs were evidently higher than in NACWs.

Conclusion: The ubiquitous nature of the Aspergillus species and slow settling rate due to small spore size, makes it the most dominant fungal organism retrieved in the air sampling conducted. No strict numerical guidelines available for the spore counts of Aspergillus species, to assess contamination rate. However, according to Health Protection Surveillance Centre, 2018, values of CFU/m³ of most of the isolates not only by Aspergillus species showed non-compliance with the threshold level documented.


Keywords


indoor air sampling; ventilation type; nosocomial; Andersen air sampler; relative humidity; temperature

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