Table of Contents
Greener Journal of Microbiology and Antimicrobials
Vol. 7(1), pp. 1-6, 2025
ISSN: 2354-2284
Copyright ©2025, the copyright of this article is retained by the author(s)
https://gjournals.org/GJMA
DOI: https://doi.org/10.15580/gjma.2025.1.041425073
Department of Microbiology, Faculty of Science, Niger Delta University.
Methods. This study aimed to determine the populations of the fungal species related with four different floor types (rug, carpet, tile, and vinyl) in an indoor environment. A total of sixteen (16) samples were examined. The total fungal population was enumerated using the pour plate method on Potato Dextrose Agar.
Results: The mean (mean ±STD) fungal population in the tile samples ranged from 4.0± 1.52 to 19± 1.52. The carpet samples ranged from 6.0 ± 4.16 to 19 ± 1.52; the vinyl samples ranged from 3.33 ± 1.52 to 16 ± 1.15. The rug samples ranged from 7.3 ± 1.152 to 18 ± 3.00. The analysis of variance (ANOVA) indicates positive and significant statistical differences between the fungal populations on the various floor types. In this study, seven different fungal species were identified: Penicillium spp, Yeast spp., Aspergillus spp., Rhizopus spp., Fusarium spp., Trichophyte spp., and Mucor spp. These species were detected in almost all the floor types. However, Fusarium spp. was not found on carpet floors, while Trichophyte spp. was not found on carpet, vinyl, or rug floor types. The seven species detected recorded varying degrees of occurrence. Aspergillus spp. (33%), Yeast spp. (16%), Penicillium spp. (13%), Rhizopus spp. (13%), Mucor spp. (13%), Fusarium spp. (11%), and Trichophyte spp. (1%).
Conclusion: This study demonstrates that the populations and types of fungal species on floors depend on the type of floor covering. Therefore, floor coverings should be properly cleaned at regular intervals to reduce the accumulation of dust and fungal species.
Article No.: 041425073
Type: Research
Full Text: PDF, PHP, EPUB, MP3
DOI: 10.15580/gjma.2025.1.041425073
Accepted: 19/04/2025
Published: 23/06/2025
*Corresponding Author
Daokoru-Olukole, C. G.
Email: dkchinma@gmail.com
Phone: +2347038730020
Keywords: Fungal spores, Aspergillus, Mycotoxin, Floor types & House dust.
People spend much time indoors, especially in residential and commercial settings. Therefore, indoor air quality (IAQ) is essential for their health and comfort. Fungal contamination can negatively impact indoor air quality (IAQ) and is a significant source of indoor air pollution. There are several potential internal and external sources of fungal contamination in indoor environments. According to Mendell et al. (2011), internal sources of moisture problems include water leaks, condensation, and high humidity levels, which foster the perfect environment for the growth of fungi. By permitting the buildup of dust and organic waste, which act as nutrients for fungal development, poorly maintained ventilation systems can also lead to fungal contamination ((Daokoru-Olukole and Olanbiwoninu, 2019; Burge, 2014; Kembel et al., 2012).
According to Hospodsky et al. (2014), outside air, dirt, and organic materials transported inside by windows, ventilation systems, and human activity are outside sources of fungal contamination. Many fungal spores can be found in the outside air, penetrating indoor environments and adding to the overall fungal load (Mendell et al., 2011). Additionally, soil and organic materials can bring fungal propagules into indoor environments, especially in structures near outside vegetation or with direct ground contact (Adhikari et al., 2016; Daokoru-Olukole, 2019).
Several factors foster an environment conducive to fungal growth and determine the survival and growth of fungal species in indoor environments (Adams et al., 2013) These include temperature, availability of nutrients, moisture and relative humidity, occupancy and human activity, indoor air quality (IAQ) factors (ventilation, air exchange rates, and air filtration), and building materials (Mendell et al., 2011).
Numerous health consequences, including allergic reactions and respiratory issues, can result from indoor exposure to fungal pollutants. In vulnerable people, inhaling fungal spores and mycelial fragments can cause allergic rhinitis, exacerbations of asthma, and hypersensitivity pneumonitis (Pasanen et al., 2011; Green et al., 2007). People with weakened immune systems, including those receiving chemotherapy or living with HIV/AIDS, are more vulnerable to Aspergillus species-caused invasive fungal infections (Mendell et al., 2011).
These infections have significant rates of morbidity and mortality and can present as severe lung infections, sinusitis, or disseminated infections. Furthermore, human health may suffer from exposure to mycotoxins generated by specific fungal species, such as Aspergillus. For instance, the potent carcinogens known as aflatoxin generated by Aspergillus flavus and Aspergillus parasiticus have been connected to the onset of liver cancer (Bennett & Klich, 2003). Other mycotoxins linked to nephrotoxicity, immunosuppression, and other adverse health effects include gliotoxin and ochratoxins (Samson et al., 2014).
The degree of indoor fungal contaminants in the air is related to the kind of floor used in interior spaces (Hedayati et al., 2010; Viegas et al., 2014). Therefore, this study was conducted to investigate the fungal populations in four different floor types: tiles, carpet, vinyl, and rug. This study will provide insight on the types of fungal species and their concentrations on different floor types, thereby creating a baseline data for analysisng the potential health risks associated with indoor dust.
Sampling
This study was conducted in Ekeki, Amassoma, Kpansia, and Swali, Bayelsa State, between April and May 2023, just at the onset of the rainy season. Four floor types were sampled: tiles, carpet, vinyl, and rug. All the floor types were collected in each location. A total of sixteen (16) samples were collected from this study.
Mycological Analysis
One (1) gram of the dust samples was weighed using ab electronic weighing balance. The samples were poured into test tubes containing 100ml of 0.85% normal saline. After that, a ten-fold serial dilution was performed up to the fourth dilution. The fungal populations were cultivated on Potato Dextrose Agar using the second dilution. The plates were incubated at 30oC temperatures for five days. After incubation, the plates were observed for the number and types of fungal colonies.
Identification of Fungal Species
The plates were examined for the morphological characteristics of the fungal colonies. The macroscopic observation used a hand lens aimed at determining the fungal culture’s shape, growth, and color. The examination and microscopic examination of fungal isolates require the observation of microscopic features such as shape, size of hyphae, shape of sporangia, conidia, conidiophores, and spores.
Using a flamed inoculating needle, the edge of each colony is picked, and slides of the different colonies are made. A drop of lacto-phenol cotton blue stain is added to the slides, covered with a cover slip, and examined under the microscope using x100 and x400 magnification starting from the third day of the culture. The microscopic characteristics observed were recorded accordingly.
Statistical Analysis
The population of fungal species in the various floor types was assessed using descriptive statistics (mean) and analysis of variance (ANOVA) at a level of p<0.05 to determine a positive significant statistical difference. The prevalence of fungal species was described using frequency and percentage of occurrence.
The results show that the fungal population in the different floor samples varies Table 1. Four different floor types were analyzed in four different locations. A total of sixteen (16) samples were examined. The fungal population in the tile samples ranged from 4.0 ± 1.52 to 19 ± 1.52. The carpet samples ranged from 6.0 ± 4.16 to 19 ± 1.52; the vinyl samples ranged from 3.33 ± 1.52 to 16 ± 1.15. The rug samples ranged from 7.3 ± 1.152 to 18 ± 3.00. The analysis of variance (ANOVA) indicates positive and significant statistical differences between the fungal populations of the various floor types.
Table 1: Comparison of Fungal Populations between Flooring Materials
Mean ± STD
12 ± 3.7a
*Mean in the same row bearing different alphabets indicates significant statistical difference (p<0.05) and vice versa.
The seven species were detected, and varying degrees of occurrence were recorded. Penicillium spp (13%), Yeast spp (16%), Aspergillus spp (33%), Rhizopus spp (13%), Fusarium spp (11%), Trichophyte spp (1%), and Mucor spp 13%) respectively. Therefore, Aspergillus spp (33%) recorded the highest percentage of occurrence with two species, A. niger and A. flavus; while the least was recorded by Trichophyte spp (1%).
Table 2: Identification of fungal species.
Aspergillus flavus
Turn dark,
Yellow to green colony surface spherical
Figure 1: Percentage of occurrence of fungal isolates.
The identification of the fungal species was done based on the cultural features and microscopic features. Seven different fungal species were identified; Penicillium spp., Yeast spp., Aspergillus spp., Rhizopus spp., Fusarium spp., Trichophyte spp., and Mucor spp.
This study aimed to ascertain the number of fungus species present in different types of floors. The findings indicate notable differences in the fungal populations among the various floor samples. However, we also noticed geographical differences in the fungus species populations linked to floor types. For instance, the largest fungal population (19 ± 1.52) was found in the dust collected from carpets in locations 1 and 4, whereas the highest fungal population (19 ± 1.52) was found in the tile samples in locations 2 and 3. The analysis of variance (ANOVA) results show that the fungal populations of the different floor types differed statistically in a positive way.
The variances observed in the fungal population may be due to several factors. According to Mendell et al. (2011), a significant number of fungal spores can be found in outdoor air, which can penetrate indoor environments and increase the overall fungal load. Additionally, soil and organic materials can bring fungal propagules into indoor environments, especially in structures near outside vegetation or with direct ground contact (Adhikari et al., 2016).
Furthermore, there have been reports that the kind of floor may affect the number of fungus species. As a result, we propose that the greater the floor type’s capacity to retain dust, the greater the number of fungi that will grow there since more dust particles will provide abundant nutrients for their growth. Hospodsky et al. (2014) found that Aspergillus species need organic resources to proliferate, which is consistent with this theory. Building materials, including wood, and plasterboard, can act as a source of nutrients for the growth of fungi (Burge, 2014). Fungi can also obtain nutrients from organic waste, dust, and biofilms that are present on surfaces of house furniture’s (Ahmed et al., 2011) and floor coverings (Hospodsky et al., 2014).
Seven distinct fungal species were identified: Penicillium, Yeast, Aspergillus, Rhizopus, Fusarium, Trichophyte, and Mucor. These species were found on practically every kind of floor. However, Trichophyte species were not detected on carpet, vinyl, or rug floor types, whereas Fusarium species were not detected on carpet floors.
The seven species that were found were noted in different levels of occurrence. Aspergillus spp. (33%), Rhizopus spp. (13%), Fusarium spp. (11%), Trichophyte spp. (1%), Penicillium spp. (13%), and Yeast spp. (16%), in that order. As a result, Aspergillus species (33%) had the highest percentage occurrence and Trichophyte species (1%) recorded the lowest percentage of the occurrence. A variety of factors can explain the combined frequency of Aspergillus species.
The result of our study is in agreement with the findings of Diba et al., (2007) that showed the higher amount of air borne spore of Aspergillus species in all the floor types. A. niger and A. flavus were the two Aspergillus species isolated from floor types and our study data showed A. niger as the most predominantly isolated species.
Aspergillus species can flourish in various environments, including soil, decomposing plants, indoor dust, and organic materials, according to Araujo and Rodrigues (2004). They also have a wide range of growth requirements. According to Hedayati et al. (2010), they are incredibly tolerant to high moisture or humidity levels (Dannemiller, 2017), creating the perfect environment for their proliferation and sporulation. In light of this, we hypothesize that floor types will best favour Aspergillus species development with the highest humidity and moisture retention levels. In a similar study, the presence of Aspergillus species in dust samples taken from Portuguese school libraries was examined by Madureira et al. (2017). According to the study, A. fumigatus and A. versicolor were the most frequently found species gathered air samples from several rooms in residential buildings for a different study. The findings demonstrated the prevalence of Aspergillus species in indoor air, with A. fumigatus and A. versicolor being the most often detected species which is contrary to our findings where A. niger and A. flavus were most detected in our study.
The detection and monitoring of Aspergillus species in indoor environments are crucial for assessing the risk of exposure and putting appropriate control measures in place. Exposure to fungal contaminants in indoor environments can result in various health effects (Alshareef et al., 2019), particularly respiratory problems and allergic reactions. This is because different types of floors are more likely to contain different fungal species (Daokoru-Olukole and Olanbiwoninu, 2019). In vulnerable people such as immunocompromised patients inhaling fungal spores and mycelial fragments can cause allergic rhinitis, exacerbations of asthma, and hypersensitivity pneumonitis (Pasanen et al., 2011; Green et al., 2007).
The predominance of Aspergillus species on all the floor types is of high pathological importance, and are known for their ability to secrete biologically active chemical compounds such as mycotoxins, antibiotics, and immune-suppressants (Goldman and Osmani, 2007). A. niger, also known as black mold can contaminate fruits and vegetables. During sweeping or cleaning of the floor covers dust particles can be re-suspended and will eventually settle on any uncovered food where hygienic practice is not strictly adhered to. A. niger produces ochratoxin A and are known to cause otomycosis- an infection of the ear.
Various strategies can be implemented to maintain good indoor air quality and minimize fungal contamination. Proper moisture control is crucial in preventing fungal growth, as moisture is a key factor for fungal colonization (Mendell et al., 2011). This can be achieved through regular inspection and maintenance of buildings, including prompt leak repair, adequate ventilation, and appropriate humidity control measures (Pasanen et al., 2011). Routine cleaning of the floor covers must not be compromised.
This comparative mycological analysis of different indoor floor types in Bayelsa State, Nigeria, reveals the presence of various fungal species, highlighting the importance of proper floor maintenance and hygiene practices. The study’s findings can suggest ways for reducing fungal contamination and promoting healthier indoor environments in the region.
Based on the study’s findings, it is recommended that residents in Bayelsa State prioritize regular cleaning and disinfection of floors, particularly in high-traffic areas. Additionally, the use of mold-resistant materials and proper ventilation systems can help reduce fungal growth and improve indoor air quality, ultimately contributing to a healthier environment for occupants.
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Daokoru-Olukole, CG; Pureaziba, N (2025). Comparative Mycological Analysis of Different Indoor Floor Types in Bayelsa State, Nigeria. Greener Journal of Microbiology and Antimicrobials, 7(1): 1-6, https://doi.org/10.15580/gjma.2025.1.041425073.
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