UGent Faculteit Diergeneeskunde faculteit, vakgroep farmacologie, toxicologie en biochemie, onderzoeksgroep biochemie
Abstract bachelorproef 1 2016-2017: Flowcytometrische viabiliteitsbepaling van Esherichia coli na blootstelling aan biociden en antibiotica
Biocides are biochemistry products used for the prevention of animal sickness and to control zoonosis. There are indications that the usage not only can cause biocide resistance but also rises the chance to develop antibiotic resistance. With a recent optimized flowcytometry method it is possible to determine the viability of E. coli based on membrane integrity and potential after a dual fluorescent DIBAC(4)3 / PI staining. Being able to measure the viable but non culturable bacteria, flowcytometry is a huge advantage to the standard plate-count method.
In this study the new method will be used in a routine experiment of E. coli strains, isolated from chicken and pigg company’s and will evaluate the effect of biocide on antibiotic resistence.
The first goal of the research was to determine the BKC concentration to be used in the experiment. A BKC concentration of 0.00675 g/l was chosen because a minimal effect on the viability and a remaining 7 log bacteria concentration was observed and is a good basal start for a second incubation with antibiotics to determine susceptibility.
The second objective was to determine the viability of two reference strains (ATCC25922 and MB4369) and four field isolates (VP11, KQ26, KL6 and VA57). The reference strains showed an increased resistence after a BKC incubation.
For each field isolate the amount of living bacteria based on plate count increased which indicates an increased resistence after a BKC treatment. The percentages of the DIBAC+/PI-, presumed VBNC bacteria show a variable effect, dependent of the field isolate and the antibiotic concentration. In general an increase of VBNC is seen after biocide treatment, what indicates that this subpopulation is part of the resistance mechanism of the bacteria. This subpopulation should be further identified using e.g. efflux pump assay and PCR as described in literature of Salmonella exposure to biocide challenge.
In general the count-plate method and the flowcytometry method are complementary to each other. The data from both methods are necessary to evaluate the effect from BKC on antibiotic resistence.
Abstract bachelorproef 2 2016-2017: Optimization of PCR with specific primers for SNP detection in fire salamanders
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Prof. dr. Evelyne Meyer
+32 9 264 73 55