In the present study, many fungi were isolated from indoor swimming pools. Sensitivity of the isolates to disinfectants varied depending on the type of disinfectant and exposure times. Accordingly, just washing the pools with a disinfectant is not a suitable method for cleaning. For efficient cleaning, the disinfectant must remain on the surfaces for an appropriate period. Clean and safe environment of swimming pools is relaxing for swimmers. The absence of effective disinfectant in swimming pools makes the pools an important source of microorganisms including fungi (1). There are reported data about bacterial and fungal contamination of public indoor swimming facilities due to sufficient moisture for fungal growth (2), (7), (16). In this study, sampling was done after the sterilization program and isolation of the fungi in different parts of the pools revealed the inappropriate cleaning.
In the present study, 35 various species of fungi like dematiaceous, hyaline hyphomycete, yeast, and dermatophyte were isolated from the pools. In epidemiologic studies of fungi in Italy and Poland on indoor swimming facilities, the similar genus of filamentous and yeasts were detected (7), (16). In two cities of Iran, researchers reported various kinds of fungal species including Aspergillus spp., Penicillium spp., dematiaceous fungi, Rodotorolla, Fusarium, and dermatophytes (1), (17). The most contaminated places were the dressing rooms, changing shoe areas, and showers. In the literature, also showers, dressing rooms, the bottoms of the swimming pools were reported as the most contaminated places in the pools (1), (17). Our study revealed a high prevalence of fungal species in the indoor swimming pool facilities, consistent with previously published studies.
Hyaline hyphomycetes in public swimming pools and/or baths are identified as predisposing factors for many infections like otomycoses. From all the monitored facilities, Aspergillus spp., and Penicillium spp., were constantly isolated. Significantly, allergic bronchopulmonary aspergillosis, asthmatic and fungal sinusitis are some characteristic manifestations of hypersensitivity to fungi, particularly due to Aspergillus species. Isolation of such airborne microorganisms raises concerns for possible onset of adverse health effects among patrons and employees (16). Bush et al. affirmed that although fungi such as Aspergillus and Penicillium, might be found in normal indoor environments at high levels, it is specifically a health risk for those allergic to the mold (18).
Disinfectants are chemical agents that play an important role in controlling microorganisms in the environments by reducing their count. The specific time and temperature needed to kill the microorganisms must be considered as per the respective manufacturers’. Sodium hypochlorite solutions (NaOCL), commonly known as bleach, is a chemical compound with a pale greenish-yellow dilute solution and stable in the refrigerator. It is widely used as a disinfectant and bleaching in the house. Hydrochloric acid (H2O: HCl, liqueur de Javel) is the aqueous solution of hydrogen chloride. It is a colorless fluid with a pungent smell. It is used on a large scale like in agriculture, food and glass industries, lime, and waste disposal industries. Hydrochloric acid can be used to disinfect water and prevent algae and shellfish growth and disinfection of the house, pools, odor removal, surface purification, bleaching, and water disinfection. Isopropyl alcohol is isomer of 1-propanol and ethyl methyl ether with strong odor and use as an antiseptic. Chloroxylenol (Dettol) is an antiseptic used for skin disinfection and surgical instruments cleaning. It is also used within several household disinfectants and wound cleaners. Depending on the type of fungus, the antifungal activities of these disinfectants were different. There are limited data about the effect of disinfectants on filamentous fungi. The response of micro-organisms to disinfectants varies and filamentous fungi are more resistant to disinfectants than yeasts and non-sporulating bacteria (19). Time and concentration are the two influential factors in increasing of antifungal activity of disinfectants (20). Limited studies have addressed the antifungal activity of disinfectants.
Mattei and co-worker reported that Chlorhexidine- cetrimide, benzalkonium chloride, and a chlorophenol derivative presented effective property against all Aspergillus isolate, except for the A. flavus strain (21). Sodium hypochlorite in Mattei et al. was ineffective against three A. fumigatus, three A. flavus, and one A. niger isolate. In the present study, after 2.5 minutes, the mean MVC/ml of isolated Aspergillus sp. was 3 colonies (21). In a study carried out by Nowrozi and co-workers, in the low dilution (2.5%) of Chloroxylenol at 15 min contact time, all isolates were resistant but with the increase of contact time, the resistant dcresed (20). In our study, with an exposure time of 2.5 minutes, Sodium hypochlorite and Chloroxylenol were acceptable for killing these fungi and after 5 minutes Hydrocholoridric acid was also found effective. Isopropyl alcohol was not suitable for killing the isolated Aspergillus spp.
In the present study, dermatophytes were isolated from the surface of pool environments. Some of the isolates are responsible for human dermatophytosis like T. rubrum which is the etiologic agent of the athlete’s foot (16). In the current study, with 2.5 minutes’ incubation period, Chloroxylenol and Sodium hypochlorite were the most effective on dermatophytes. Other disinfectants exhibited antifungal effects on dermatophyte fungi, too. Dematiaceous fungi due to melanin and sporopollenin in cell components might be involved in cellular resistance to physical and chemical agents (9),(11). They can cause invasive and systemic infections in immunocompromised patients. Our results showed Sodium hypochlorite was effective against these fungi at all times. Chloroxylenol was effective after 5 minutes while other disinfectants were effective after 10 minutes. In Nowrozi et al, Chloroxylenol® 2.5% solution was reported as an effective disinfectant against Cladosporium spp. (20). The findings of Sandle et al. showed the MIC90 value of Benzalkonium chloride against Alternaria spp, was higher than that for other hyaline fungi (11). In the present study, Sodium hypochlorite was an effective disinfectant after 2.5 minutes on Mucorales. The MVC/ml of Mucorales after 5 minutes of incubation time with other disinfectants was reliable. In one study, Chloroxylenol® 2.5% solution was the most effective disinfectant against Cunninghamella and Mucor spp. than Betadine®, Benzalkonium chloride, and Chlorhexamed® (20). Candida species can cause infection on cutaneous and mucosal sites of human bodies. Sodium hypochlorite was an effective disinfectant after 2.5 minutes on Candida spp. After 5 minutes, Chloroxylenol and Choloridric acid were effective. Isopropyl alcohol was not a suitable disinfectant against Candida spp.