Exploring the susceptibility of Enterococcus to quaternary ammonium compounds and copper, and the impact of various environmental conditions on its tolerance
學生姓名:
江虹蓁
指導教授:
林泓廷
學期:
112下
摘 要:
Copper and quaternary ammonium compounds (QACs) are commonly used antibacterial agents in human, animals, and the environment. Copper and QACs have been implicated in the co-selection and dissemination of antibiotic-resistant bacteria (ARB). This study aims to explore the susceptibility of enterococci to QACs and copper and how different environmental conditions affect their tolerance. The results showed that although enterococci do not seem to be significant hosts of QAC tolerance genes, they can share and transfer known tolerance genes with other bacteria in the same environment. Compared to didecyldimethylammonium chloride (DDAC), enterococci showed higher tolerance to benzalkonium chloride (BC). Growth condition tests showed that Enterococcus exhibited a delayed exponential multiplication phase at 22°C and pH = 5, resulting in an increased minimum inhibitory concentration (MIC) for BC. In poultry farming, the study shows that Cu used in organic trace mineral feed or inorganic trace mineral feed formulations for intensive chicken production systems does not have a major impact on the expansion of Cu-tolerant and multidrug-resistant (MDR) Enterococcus spp., despite the high occurrence of MDR strains found during chickens' lifespan and in derived meat. There are high rates of truncated Cu tolerance in the tcrYAZB genotype with low CuSO4 MICs, and regardless of Cu feed type, there are low Cu concentrations in chicken feces and meat. Research has shown that Enterococcus are tolerant to QAC and copper. Environmental variables, including genetics, may lead to enhanced antibacterial agents tolerance in enterococci. It may provide insights into reducing the ARB in environmental and poultry farming.
江虹蓁.pdf