Diversity of antibiotic resistance genes in the waters of greater Pearl River Delta : application as pollution indicator

Abstract

In our attempt to track pollution, we targeted Escherichia coli (faecal indicator bacteria) and their carriage of a bacterial adaptive response mechanism related to antibiotic resistance (class 1 integron, by detecting intI1 gene). Our results from two studies at different scales showed that E. coli bearing the clinical variant of intI1 could be a promising proxy for pollution monitoring in aquatic systems where E. coli is present. Although tracking of intI1 does not overtake the need to detect specific types of contaminants, it can provide a relatively fast and reliable early assessment of pollution. A higher prevalence of intI1 was found in E. coli isolated from areas with a higher level of human disturbance. We demonstrated that E. coli genotypes and the cryptic clade II of Escherichia were differentially distributed in aquatic environments with differential human impact. Their carriage of the intI1 genes also reflected the distinction in human impact. Altogether, this work revealed the new genetic diversity of E. coli and cryptic clades embedded in selected subtropical aquatic habitats, especially relatively pristine sites, which will aid a more thorough understanding of the extent of their genetic and functional variations in relation to diverse habitats with varied conditions. We also illustrated the complex pollution-related conditions (algal bloom, hypoxia, faecal pollution, etc.) that could affect environmental resistomes.

Date of Award	2022
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Stanley Chun Kwan LAU (Supervisor) & Joseph Kai Cho KWAN (Supervisor)