Indoor Bacterial and Fungal Burden in “Moldy” versus “Non-Moldy” Homes: A Case Study Employing Advanced Sequencing Techniques in a US Metropolitan Area

Abstract

The presence of fungi in the indoor environment is associated with allergies and other respiratory symptoms. The aim of this study was to use sequencing and molecular methods, including next-generation sequencing (NGS) approaches, to explore the bacterial and fungal communities and their abundance in the indoor environment of houses (n = 20) with visible “moldy” (HVM) and nonvisible “non-moldy” (HNM) in Memphis, TN, USA. Dust samples were collected from air vents and ground surfaces, and the total DNA was analyzed for bacteria and fungi by amplifying 16S rRNA and ITS genes on the Illumina Miseq. Results indicated that Leptosphaerulina was the most abundant fungal genus present in the air vent and ground samples from HNM and HVM. At the same time, the most abundant bacterial genera in the air vent and ground samples were Propionibacterium and Streptococcus. The fungi community diversity was significantly different in the air vent samples. The abundance of fungal species known to be associated with respiratory diseases in indoor dust samples was similar, regardless of the visibility of fungi in the houses. The existence of fungi associated with respiratory symptoms was compared with several parameters like dust particulate matter (PM), CO2 level, temperature, and humidity. Most of these parameters are either positively or negatively correlated with the existence of fungi associated with respiratory diseases; however, none of these correlations were significant at p = 0.05. Our results indicate that implementing molecular methods for detecting indoor fungi may strengthen common exposure and risk assessment practices.

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

“…According to recent studies 71 – 76 , the residential buildings with the presence of water damage and hidden dampness showed significantly higher levels of indoor molds and bacterial concentrations. Similarly, on-site exposure assessments were conducted using the IR thermal camera to determine the presence of water damage and hidden moisture.…”

Recent Advances in the Detection of Indoor Fungi

“…In the field of new detection methods, Chauhan et al [ 8 ] implemented next-generation sequencing approaches to explore the bacterial and fungal communities and their abundance in dust samples collected from air vents and ground surfaces. Regardless of the visibility of fungi in the homes, the abundance of potentially pathogenic fungal species was similar.…”

“…The contributors to this Special Issue provided insights into current issues in indoor mycology, particularly from a methodological [ 6 , 7 , 8 , 11 , 13 ], metabolic/toxicological [ 10 , 11 , 12 , 14 , 15 ], and taxonomical [ 8 , 9 , 13 , 16 , 17 ] point of view. Overall, two key messages emerge: (i) the current detection methods appear to be shifting from air sampling [ 11 , 12 ] to dust sampling [ 6 , 8 , 9 , 10 , 13 ], as the latter provides information on longer exposure periods and a higher biodiversity; (ii) the microbial composition of buildings is still largely unknown [ 9 , 13 , 16 , 17 ]. Our authors demonstrated that the indoor environment should also be a focus of taxonomical research, especially with regard to wooden and cellulosic materials [ 14 , 15 , 16 , 17 ], which proved to have a relatively high biodiversity.…”

“…The contributors to this Special Issue provided insights into current issues in indoor mycology, particularly from a methodological [6][7][8]11,13], metabolic/toxicological [10][11][12]14,15], and taxonomical [8,9,13,16,17] point of view. Overall, two key messages emerge: (i) the current detection methods appear to be shifting from air sampling [11,12] to dust sampling [6,[8][9][10]13], as the latter provides information on longer exposure periods and a higher biodiversity; (ii) the microbial composition of buildings is still largely unknown [9,13,16,17].…”