Susceptibility of nongrowing uropathogenic Escherichia coli to fluoroquinolones: killing and induction of the SOS response
Date
2023
Authors
Journal Title
Journal ISSN
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Publisher
Tartu Ülikool
Abstract
Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections.
UPEC is capable of entering the host cells and adapting to an intracellular lifestyle. This
provides bacteria protection against host defensive mechanisms and antibiotics, leading to
chronic and recurrent infections. Due to the limited nutrients inside host cells, bacteria are
nongrowing. Nongrowing bacteria are not killed by most bactericidal antibiotics. However,
some antibiotics of the fluoroquinolone group - gatifloxacin and ofloxacin – are known to
be effective. According to an unpublished study, it was suggested that fluoroquinolones do
not kill nongrowing bacteria but poison them. This study investigated the killing efficiency
and in-duction of SOS response by a set of different fluoroquinolones in various growth
conditions. Specifically, bactericidal effect on stationary phase culture before and after 1M
NaCl incubation and induction of SOS response for growing stationary phase and regrowing
cultures. The results of this thesis have supported the hypothesis of delayed bacterial death
after fluoroquinolone poisoning.
Description
Keywords
Fluoroquinolones, UPEC, SOS response, antibiotic tolerance