Molecular Detection of Mycobiota in Drinking Water at Four Different Sampling Points of Water Distribution System of Jeddah City (Saudi Arabia)

Abstract

The study included collection of water samples (150 samples) from 10 different branches belonging to each water network in Jeddah City (Saudi Arabia). Samples included treated water (30 samples) and tap water in some hospitals (30 samples from cold water tap and 30 samples from hot water tap) and private houses (60 samples). According to results of the traditional identification methods, the highest isolation frequency of fungi was recorded in the private homes (90%), whereas the total isolation frequency was 73.3%. Molecular genetic methods, including PCR amplification and sequencing of ITSs of unculturable fungi, were also considered. All of the sequenced strains were identified by similarity searches with ITS sequences in EMBL/GenBank. All strains that were detected in the examined water samples, which collected from treatment stations and private houses, could be defined by traditional methods. We detected Acremonium strictum as an unculturable strain in hospital cold water. Also, three fungal species were detected in hospital hot water (HHW) by both the traditional methods and the methods of molecular diagnostics (partial sequencing of the ITS gene). In addition, 6 other species including Acremonium strictum, Cladosporium cladosporioides, Rhizopus azygosporus, Penicillium citrinum, Penicillium oxalicum, and Trichoderma viride were identified using the molecular method but were not phenotypically identified in HHW. It can be concluded that drinking water in Jeddah City contains many different fungal species that do not affect the quality of drinking water. However, some of these strains may cause disease in human beings by producing mycotoxins or by causing allergic responses. This study indicates the importance for quality assurance of applying molecular diagnostic techniques as a rapid and accurate technique for detecting the presence of fungi in potable water.

Keywords:

• drinking water
• unculturable fungi
• DGGE
• ITS

Acknowledgments

This work was supported by a grant (Contract No. 18-012-430) from King Abdulaziz University, Kingdom of Saudi Arabia. The authors are very grateful for the deanship of scientific research at King Abdulaziz University for their financial support.