Omnipresent Integrons

1
Omnipresent Integrons

• Julian Davies
• Department of Microbiology and Immunology
• University of British Columbia, Vancouver

2
What are Integrons?

• DNA elements which capture and express circular
  DNA elements ( gene cassettes)
• Cassettes frequently encode resistance to
  antibiotics
• Classes of integrons exist based on integrase
  gene sequence. (IntI1gtIntI2gtIntI3)
• Widely distributed in the environment

3
Microbes, their Genes, Populations and
Interactions

• AGRICULTURE

PRISTINEENVIRONMENTS
HOSPITALS
COMMUNITY
INTENSIVE CARE UNITS
WASTEWATER TREATMENT
4
Integrons in wastewater
Samples
3
20
3
IntI1
3
11
3
IntI2
3
0
0
0
1
0
IntI3
5
A composite multicomponent plasmid from a
wastewater treatment plant (Szezpanowski 2004)
6
Results - Iona
qnrA
qnrS
qnrB
1
2
3
4
1

-

-
2
3
4
-
1
2
3
4

1 kb ladder
1 influent
3 post-aeration
Treatment stages
2 aeration
4 effluent
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Quinolone resistance

• Worldwide distribution of qnr genes

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Goals of Project

• Isolate plasmids from hospital and two associated
  water treatment plants
• Sequence 100 independent plasmid DNAs
• Analyse the information in terms of integron
  structure and dissemination
• Identify resistance genes and their distribution