Global DNA Methylation Level among Ciprofloxacin-Resistant Clinical Isolates of Escherichia coli
Introduction: Fluoroquinolone resistant clinical isolates belonging to the family Enterobacteriaceae, is a major public health concern in India. Data analysis in JIPMER hospital revealed 10% rise in fluoroquinolone resistance within a span of three years suggestive of the possible involvement of...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
JCDR Research and Publications Private Limited
2016-05-01
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| Series: | Journal of Clinical and Diagnostic Research |
| Subjects: | |
| Online Access: | https://jcdr.net/articles/PDF/7830/19034_CE[Ra1]_F(GH)_PF1(ROAK)_PFA(AK)_PF2(PAG).pdf |
| Summary: | Introduction: Fluoroquinolone resistant clinical isolates
belonging to the family Enterobacteriaceae, is a major public
health concern in India. Data analysis in JIPMER hospital revealed
10% rise in fluoroquinolone resistance within a span of three
years suggestive of the possible involvement of mechanism/s
other than QRDR capable of imparting fluoroquinolone
resistance. DNA methylation regulates gene expression.
Moreover, methylated cytosine is a mutational hotspot. Thus,
DNA methylation can alter bacterial gene expression profile as
well as facilitate the bacteria in accumulating mutations possibly
leading to increased antimicrobial resistance. Therefore,
the present study was carried out to identify the potential
involvement of DNA methylation in ciprofloxacin resistance.
Aim: To elucidate and compare the methylation level of genomic
and plasmid DNA among clinical isolates of E. coli sensitive and
resistant to ciprofloxacin.
Materials and Methods: The study included 40 clinical E. coli
isolates of which, 30 were ciprofloxacin-resistant and 10 were
sensitive to ciprofloxacin. Genomic DNA (gDNA) and plasmid
DNA were extracted and quantified. Methylation levels were
elucidated using 5-mC DNA ELISA kit (Zymoresearch, California,
USA) as per kit protocol and guidelines.
Statistical Analysis: Spearman correlation 2-tailed test was
used. A p-value <0.05 was considered significant.
Results: The MIC values of sensitive and resistant strains
against ciprofloxacin ranged from 0.125 µg/mL – 0.75 µg/mL
and 8 µg/mL - >256 µg/mL respectively. No difference was found
in plasmid DNA methylation level but, the gDNA methylation
level of the resistant strains significantly differed from that of
the sensitive strains. Based on Spearman correlation test
gDNA methylation level of bacteria was found to be inversely
proportional to its MIC against ciprofloxacin with p= -0.956
(p-value < 0.0001).
Conclusion: The influence of DNA methylation over plasmidmediated quinolone resistance needs to be further confirmed
by bisulphite DNA sequencing of the plasmid-borne genes.
Extensive usage of ciprofloxacin has led to rise in ciprofloxacin
resistance possibly induced by DNA methylation. Thus rational
usage of ciprofloxacin in a clinical setting is essential to
combat the further development of ciprofloxacin resistance.
Hypomethylated genes and adenine methylation needs to
be identified to fill up gaps in knowledge concerning the
involvement of DNA methylation in fluoroquinolone resistance
exhibited by E. coli. |
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| ISSN: | 2249-782X 0973-709X |