Temporal shifts in mineral composition and microbial diversity of Chamliyal shrine clay

The clay from Chamliyal shrine has a long history of its use to treat various skin diseases particularly psoriasis, with its effectiveness linked to its mineral composition and microbial diversity. This study investigated the mineral composition and microbial diversity of the Chamliyal clay using two different media at two different time points i.e. 2008 and 2017. The results revealed a decline in mineral composition, bacterial load and diversity over the period of nine years. Molecular identification through 16S rRNA gene sequencing and subsequent BLAST analysis revealed 48 bacterial isolates in 2008 and 24 isolates in 2017 with 5 common isolates present in both the years. Firmicutes constituted the dominant phylum in both sampling years, largely due to the prevalence of Bacillus species. Proportion of isolates having antibacterial activity decreased from 12.5% in 2008 to 9.5% in 2017. The bacteria that were common in both the years did not show antibacterial activity in both the years. It was observed that not only the mineral composition and microbial diversity of the Chamliyal clay, but also the antimicrobial potential of the isolates, had decreased. Therefore, evaluating the actual impact of Chamliyal clay on healing necessitates further investigation through human applications.