Department of Biological SciencesMany infectious diseases may one day become uncontrollable. Thus, antibiotic-resistant bacteria have become a serious issue. And as the failing of antibiotics becoming a big problem, the needs for finding new antimicrobial agents are increasing. For an alternative of antibiotics, predatory bacteria are a promising approach since Bdellovibrio bacteriovorus is an obligate predator of other Gram-negative bacteria. However, even after predation by B. bacteriovorus, a small sub-population of prey cells remains a characteristic that is similar to bacterial persisters. And in a long-term predation in the continuous system was conducted to characterize these remaining sub-population of prey. One interesting finding from long-term predation is phenotypic changes of prey. So-called small colony variants (SCVs). The bacterial persisters are a small sub-population of the entire culture that exists within a dormant state and, although they lack any genetic mutations or modifications, they survive longer during exposures to antibiotics due to this temporal state. As these persister cells survive in the presence of different antibiotics, their existence is considered important as they may cause chronic or recurrent infections.
In this study, I characterized both persister cells induced by a pre-treatment with antibiotics, i.e., antibiotic persisters (AP), and the sub-population of prey cells which survive predation by B. bacteriovorus HD100, i.e., the predation persisters (PP) cells. I found AP cells were also resistant to B. bacteriovorus predation and, conversely, the PP cells were better at surviving antibiotic treatments. The characteristics of these cultures were studied further to find common features for the two persister populations, by comparing the expression level of persister related genes in SCVs using transcriptome analysis.clos
