Assessment Of Airborne Microbial Community In Indian Cities During The Middle East Dust Storm

Globally dust storms have greatly affected air quality, and nearly 5.0 billion tonnes of dust undergoes migration every year. A plethora of microorganisms spread far and wide along with the dust particles during dust storms. In April 2015, a dust storm originated from the Middle East and travelled to many Indian cities. We analysed the impact of the dust storm on the diversity and composition of aerial microorganisms using cultivation-based methods. Sampling was done in three cities (Mumbai, Lonavala and Pune) during a dust storm day (DSD) and a post-dust storm day (PSD). A total of 580 morphologically different bacteria and then ten mycelial fungi were isolated during the study. Identification based on MALDI-TOF MS biotyping, sequencing of 16S rRNA gene and ITS region revealed that the bacterial isolates belonged to 32 different genera and fungi to four different genera. Principal coordinate analysis exhibited separate grouping of DSD and PSD samples, indicating the shift in microbial communities. Osmotolerant and halotolerant bacterial genera, viz. Psychrobacter and Exiguobacterium were recorded specifically during DSD. The proportion of opportunistic pathogens, including Staphylococcus and Enterobacter was high during DSD in comparison to PSD. Overall, the study reveals the influence of dust storms on the aerial microbial composition and indicates the possible spread of specific microbial species during a dust storm event.