Karakterisering av antibiotikaresistens hos Escherichia coli isolert fra villrein i Norge
Master thesis
Permanent lenke
http://hdl.handle.net/11250/295208Utgivelsesdato
2015-08-06Metadata
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- Master's theses (KBM) [885]
Sammendrag
Antibiotics revolutionized the medical industry when it was introduced due
to
its
ability
to
cure infections that previously were difficult to treat. The increased use of
antimicrobial agents has increased the selection pressure that selects for resistant bacteria.
This has led to higher prevalence of resistant infectious bacteria, especially in clinical
environments. Horizontal gene transfer (HGT) has made this possible by mechanisms as
conjugation, transduction and transformation. Mobile genetic elements, such as plasmids,
integrons and transposons, are important for
distribution
of
the resistance genes. Exchange
of mobile genetic elements that contain antimicrobial resistance can contribute to the
occurrence of new antimicrobial resistance replicons.
Antimicrobial resistant Escherichia coli found in wild reindeer in Norway was
examined in this study. The purpose of the study was to investigate the isolates and their
resistance genes. Forty-two isolates were included in the study; 27 resistant and 15 nonresistant.
Disc dilution and MIC (minimum inhibitory concentration) were used to assess the
phenotypic resistance pattern of the isolates. Illumina whole-genome sequencing was used to
obtain sequence data, and several online tools were used to investigate the genotypic
resistance. Phylogenetic groups were determined by multiplex PCR and MLSTs were
determined using MLST-Finder. Conjugation was also tested for through a conjugation test.
The results showed that multiple isolates were resistant to more than one antimicrobial
agent. Most of the isolates had high MIC-values and about 50 % transferred resistance by
conjugation test. Multiple sequences containing resistance genes were similar in construction.
A high diversity of the isolates was observed, and E. coli belonging to group A. B1, B2 and D
was found.
The information obtained in this study showed that there is antimicrobial resistant E.
coli in wild reindeer in Norway, containing known resistance genes. Furthermore, the multiresistant
replicons and similar sequences discovered in the isolates have previously been
identified in isolates obtained from human, bear and bird. This supports the fact that
resistance genes are widespread. Antimicrobial resistance is an increasing problem in the
world today and more information about the dissemination is much needed. Mapping of the
antimicrobial resistance in wild animals can give new insight to the dynamics of
dissemination and give a wider understanding of how humans have influenced it. Increased
knowledge on susceptibility in nature can contribute to better insights on how we can handle
this development.