Spatio-temporal variations in bacterial and fungal community associated with dust aerosol in Kuwait

Abstract

Kuwait is a country with a very high dust loading; in fact it bears the world’s highest particulate matter concentration in the outdoor air. The airborne dust often has associated biological materials, including pathogenic microbes that pose a serious risk to the urban ecosystem and public health. This study has established the baseline taxonomic characterization of microbes associated with dust transported into Kuwait from different trajectories. A high volume air sampler with six-stage cascade impactor was deployed for sample collection at a remote as well as an urban site. Samples from three different seasons (autumn, spring and summer) were subjected to targeted amplicon sequencing. A set of ~ 50 and 60 bacterial and fungal genera, respectively, established the core air microbiome. The predominant bacterial genera (relative abundance ≥ 1%) were Brevundimonas (12.5%), Sphingobium (3.3%), Sphingopyxis (2.7%), Pseudomonas (2.5%), Sphingomonas (2.4%), Massilia (2.3%), Acidovorax (2.0%), Allorhizobium (1.8%), Halomonas (1.3%), and Mesorhizobium (1.1%), and the fungal taxa were Cryptococcus (12%) followed by Alternaria (9%), Aspergillus (7%), Candida (3%), Cladosporium (2.9%), Schizophyllum (1.6%), Fusarium (1.4%), Gleotinia (1.3%) and Penicillium (1.15%). Significant spatio-temporal variations were recorded in terms of relative abundances, α-diversities, and β-diversities of bacterial communities. The dissimilarities were less pronounced and instead the communities were fairly homogenous. Linear discrimant analysis revealed three fungal genera known to be significantly differentially abundant with respect to different size fractions of dust. Our results shed light on the spatio-temporal distribution of airborne microbes and their implications in general health.

Composition of nasal bacterial community and its seasonal variation in health care workers stationed in a clinical research laboratory

“…It is the bacterial species that interact with the host to establish a beneficial, commensal, or pathogenic relationship [ 58 ]. From health, perspective, further understanding of network dynamics between these taxa and other microbial communities such as fungi and viruses is recommended [ 12 , 31 ]. Knowledge of the viability status of these should be taken up as metabolically active microorganisms are only potentially lethal.…”

“…A baseline study conducted on the taxonomic profiling of the airborne microbial communities of the external atmosphere demonstrated the occurrence of a variable microbial population in the inhalable and respirable air fractions in Kuwait. These variations were due to space and time [ 11 , 31 ]. This leads us to conclude that differences in RA in the same subjects between different conditions are obvious and each individuals’ microflora is jointly influenced by the working atmosphere as well as the external surroundings.…”

“…The V3 and V4 regions of the 16S rRNA gene (~600 bp) were amplified by the recommended Forward–(S-D-Bact-0341-b-S-17): and Reverse (S-D-Bact-0785-a-A-21): ) primer pairs [ 30 , 31 ]. Both primers were synthesized commercially and purchased from Thermo Fisher Scientific (Waltham, MA, USA), dissolved in 0.1 mM Tris EDTA and adjusted to 1 μM concentration.…”

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“…Kuwait is a country with high dust loading. Several pathogenic and non-pathogenic microbes have been previously demonstrated to be associated with different size fractions of dust in the country [11,31]. The incidences of allergy and asthma are highly prevalent in this country.…”

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“…GAGATGTGTATAAGAGACAGGACTACHVGGGTATCTAATC-3') primer pairs [30,31]. Both primers were synthesized commercially and purchased from Thermo Fisher Scientific (Waltham, MA, USA), dissolved in 0.1 mM Tris EDTA and adjusted to 1 μM concentration.…”