Swimming pools are suitable places for transferring the pathogenic and potentially pathogenic microorganisms to human . Factors such as swimmers’ skin infections along with the lack of pH control and inadequate disinfection of swimming pools have an important role in transferring infectious diseases .
In the present study, physiochemical parameters of swimming pools, water fungal contamination, and pools’ surroundings in Arak were investigated. Results showed that fungi species were found in 79.1% of swimming pools’ water or surface samples. These species were saprophytic fungi (74.8%), yeast species (25%), and dermatophytes species (0.2%).
Several studies in different parts of Iran and the world were done to investigate pool contamination [4, 8, 9, 11, 16, 17, 23,24,25,26,27]. Similarly to other studies in Iran, we found that saprophytic filamentous fungi were the most prevalent [11, 17, 23, 24] and Candida species were the most common fungal isolate. Similar to Rasti in Kashan and Jahanbakhsh, in Urmia, we found that fungal contamination was more common during the summer season, and the least problematic in the spring due to the fact that pools have more swimmers in summer and the heat and humidity are higher in this season .
It is in contrast to the study by Rafiei which found that 54.47% of the total collected samples were positive regarding the fungi elements. However, the corresponding rate of fungal contamination of all collected samples in the present study was more than what had been found in that study. Furthermore, the most common isolates are filamentous fungi in that study which is similar to our results .
Compared with the other studies in Iran [9, 17, 20], the lowest rate of dermatophyte species was isolated in the current study which can be due to the hygiene of the swimmers of our considered pools. In the present study, only one case of Trichophyton rubrum was isolated from foot-washing sink. In addition, in contrast to some previous studies in Iran [9, 11, 24] and elsewhere [4, 8, 26], no case of dermatophyte species was isolated from lockers, showers, pool edges, and water, which could be explained by our residual chlorine and isolation method.
In the study of Jankowski in Poland that was done on swimming pools, in contrast to the study, T. mentagrophytes was the most prevalent dermatophyte isolated, while only one species of Microsporum canis was isolated and no case of T. rubrum was isolated, which was detected in 86% of all adult dermatophytic infections. Also similar to our study, in the study of Jankowski, the most isolated species were Candida spp. .
In the study of Brandi in Rome city of Italy, in contrast to other studies, Candida spp. has been never detected, while similar to the present study, one species T. rubrum was isolated from swimming pools’ water and surfaces .
Nowadays, diseases caused by free-living amoeba including encephalitis and keratitis are increasing . In our country, various studies have been done on free-living amoeba in environmental resources including pool water. In the present study, similar to other studies in Iran and the world and in contrast to the study of Armand in Shiraz, one case of Acanthamoeba contamination out of six pools (16.6%) was isolated. In the present study, Acanthamoeba was isolated in the warm season (summer) of the year where many people are using the pools, which could be the cause of high rates of contamination [30,31,32,33].
In a study by Mafi et al. on pool water and pools of amusement parks in Tehran, they reported that the contamination rate with Acanthamoeba was 24%, which is different from the results of our study, due to the low level of contamination in this study that could be due to sampling only from the pool water, while in Mafi et al.’s study, in addition to pool water, samples were collected from the park ponds, due to being in open space and also entering of the dust to these waters which has increased the amount of Acanthamoeba contamination .
In a study conducted by Solgi et al. on the hot springs of Ardabil province, 20% of the hot springs of this province were contaminated with Acanthamoeba parasite. The reason for the difference in the results of our study and that study can be attributed to the difference in water temperature where the water temperature of the hot springs is higher than that of the pool water . The results of the present study indicate that Acanthamoeba free-living amoeba is significantly prevalent in Arak city pools and there is a potential for infection to people who are prone to free-living amoeba.
Our finding showed that the pools’ water pH was between 7.15 and 7.52, which is in accordance with the recommended reference pH for swimming pool water (7.2–8.0). The pool water pH in this study in comparison to other studies in Iran was in a better condition. In addition, unlike other studies in Iran [17, 36, 37], the residual chlorine of all swimming pools was in the standard range (1–3 mg/L). The water turbidity of the swimming pools in this study was less than 0.5 NTU, which was in the standard condition. In contrast to other physicochemical parameters in the present study and similar to study of Rasti in Kashan , the water temperature of swimming pools was more than the standard range (25–29 °C). It is known that high water temperature provides conditions for the growth of pathogenic microorganisms [35, 38].