Effect of mutant bacterial strains on infection
Vancomycin-resistant enterococci, VRE, are becoming an increasing problem in health care and is one of the leading causes of nosocomial infections (Donskey 2004). There are many factors that are contributing to the increasing problem of these bacteria, for example their high ability to acquire resistance genes through their remarkable genome plasticity (plasmids, transposons and insertion sequences), their ability to persist for 60 minutes on hands and up to four months on surfaces.
Only two new classes of antibiotics have been discovered in the last three decades, and no new antibiotics are in phase II or III trials (Ovchinnikov et al., 2016).
The bacteriocins K1 and EJ97 are new treatment options that target VRE and are in the process of development. They target Eep (also known as RseP), a membrane-associated protein that is involved in a bacterial stress response. Hence, VRE with intact Eep is expected to survive in the stressful environment imposed by the host, whereas VRE with defective Eep (mutants or targeted by K1 or EJ97) is expected to die.
The purpose of these experiments is to determine whether Eep mutants are able to establish infections in mice (skin and systemic). If the answer is no, this will indicate that bacteriocin targeting of Eep containing VRE is a realistic treatment option. To do this we will use a skin infection model and a model of systemic infection of VRE in a well-established mouse strain - BALB/c female mice
between 6 and 8 weeks.
Number of animals: 82
Severity category of the experiment – moderate. During part 1 of the experiment (skin colonization) mice are likely to experience short-term localized skin pain, but analgesic drug will be used to avoid this (Temgesic). Less likely systemic symptoms including fever, flu-like aches. During part 2 of the experiment, mice are likely to experience some discomfort due to systemic infection. However, the experiment will use doses of bacteria described in the literature to be well tolerated. We strive to maintain a stable environment with constant temperature, humidity and light conditions. Temperature and humidity is recorded on a daily basis by using sensors in relevant rack positions. We also minimize traffic in the animal room to reduce stress to the animals. Each cage has a running wheel and house to increase their activity levels and well-being. We underline the importance of avoiding stress in the lab and housing room by e.g. high-frequency sounds, sudden movements or non-gentle handling of animals.
Only two new classes of antibiotics have been discovered in the last three decades, and no new antibiotics are in phase II or III trials (Ovchinnikov et al., 2016).
The bacteriocins K1 and EJ97 are new treatment options that target VRE and are in the process of development. They target Eep (also known as RseP), a membrane-associated protein that is involved in a bacterial stress response. Hence, VRE with intact Eep is expected to survive in the stressful environment imposed by the host, whereas VRE with defective Eep (mutants or targeted by K1 or EJ97) is expected to die.
The purpose of these experiments is to determine whether Eep mutants are able to establish infections in mice (skin and systemic). If the answer is no, this will indicate that bacteriocin targeting of Eep containing VRE is a realistic treatment option. To do this we will use a skin infection model and a model of systemic infection of VRE in a well-established mouse strain - BALB/c female mice
between 6 and 8 weeks.
Number of animals: 82
Severity category of the experiment – moderate. During part 1 of the experiment (skin colonization) mice are likely to experience short-term localized skin pain, but analgesic drug will be used to avoid this (Temgesic). Less likely systemic symptoms including fever, flu-like aches. During part 2 of the experiment, mice are likely to experience some discomfort due to systemic infection. However, the experiment will use doses of bacteria described in the literature to be well tolerated. We strive to maintain a stable environment with constant temperature, humidity and light conditions. Temperature and humidity is recorded on a daily basis by using sensors in relevant rack positions. We also minimize traffic in the animal room to reduce stress to the animals. Each cage has a running wheel and house to increase their activity levels and well-being. We underline the importance of avoiding stress in the lab and housing room by e.g. high-frequency sounds, sudden movements or non-gentle handling of animals.