Land Use Land Cover structural impact on abundance of antibiotic resistant Bacillus species in Tropical Estuary of India

Abstract

In recent decades, the Land Use Land Cover (LULC) in the coastal environment along with ambient scenario of metocean condition has been considered as one of prime factors in distribution and diversity of biota. Antibiotic use and abuse are a prevalent global issue that significantly increases the levels of antibiotics in the environment and the rates at which they spread. Today, it is safe to say that mass manufacture and use of antibiotics for purposes other than medical treatment have a negative influence on both the environment and human health. The main public health worry is that bacterial strains isolated from various ecosystems are resistant to antibiotics used in human medicine, severely limiting therapeutic options and endangering the lives of afflicted individuals. The presence of antibiotic-resistant bacteria and the morphological environmental conditions that contribute to their prevalence in estuaries is poorly known. We used the Kirby Bauer disc diffusion assay for susceptibility test to examine multi-antibiotic-resistant bacteria in both water and sediments across the Amba Estuary. The study of 16S rRNA from Gram positive multidrug-resistant isolates revealed a phylogenetic uniform group of resistant Bacillus species. This study uncovers a widespread distribution of antibiotic-resistant Bacillus sp. in the estuary, regardless of salinity gradient, and establishes a link between the abundance of antibiotic-resistant bacteria and sewage-associated bacterium levels in the estuary across distinct morphology. Colonies with MAR indices of ˃0.2 were isolated and found to be 100 % ampicillin resistant. The middle and upper estuary zones had a significant percentage of antibiotic-resistant microbes. Present study showed that the LULC dominates the distribution and diversity of microbial structure rather than salinity gradient. The significant diversity of antibiotic-resistant microbes across distinct morphology in the Amba estuary reveals the importance to understand the environmental microbial distribution in estuaries and prevent environmental health risks from antibiotic-resistant bacteria.