Novel genes associated with enhanced motility of Escherichia coli ST131

Kakkanat, Asha, Minh-Duy Phan, Lo, Alvin W., Beatson, Scott A. and Schembri, Mark A. (2017) Novel genes associated with enhanced motility of Escherichia coli ST131. PLoS One, 12 5: e0176290.1-e0176290.22. doi:10.1371/journal.pone.0176290


Author Kakkanat, Asha
Minh-Duy Phan
Lo, Alvin W.
Beatson, Scott A.
Schembri, Mark A.
Title Novel genes associated with enhanced motility of Escherichia coli ST131
Formatted title
Novel genes associated with enhanced motility of Escherichia coli ST131
Journal name PLoS One   Check publisher's open access policy
ISSN 1932-6203
Publication date 2017-05-01
Sub-type Article (original research)
DOI 10.1371/journal.pone.0176290
Open Access Status DOI
Volume 12
Issue 5
Start page e0176290.1
End page e0176290.22
Total pages 22
Place of publication San Francisco, CA, United States
Publisher Public Library of Science
Language eng
Abstract Uropathogenic Escherichia coli (UPEC) is the cause of ~75% of all urinary tract infections (UTIs) and is increasingly associated with multidrug resistance. This includes UPEC strains from the recently emerged and globally disseminated sequence type 131 (ST131), which is now the dominant fluoroquinolone-resistant UPEC clone worldwide. Most ST131 strains are motile and produce H4-type flagella. Here, we applied a combination of saturated Tn5 mutagenesis and transposon directed insertion site sequencing (TraDIS) as a high throughput genetic screen and identified 30 genes associated with enhanced motility of the reference ST131 strain EC958. This included 12 genes that repress motility of E. coli K-12, four of which (lrhA, ihfA, ydiV, lrp) were confirmed in EC958. Other genes represented novel factors that impact motility, and we focused our investigation on characterisation of the mprA, hemK and yjeA genes. Mutation of each of these genes in EC958 led to increased transcription of flagellar genes (flhD and fliC), increased expression of the FliC flagellin, enhanced flagella synthesis and a hyper-motile phenotype. Complementation restored all of these properties to wild-type level. We also identified Tn5 insertions in several intergenic regions (IGRs) on the EC958 chromosome that were associated with enhanced motility; this included flhDC and EC958_1546. In both of these cases, the Tn5 insertions were associated with increased transcription of the downstream gene(s), which resulted in enhanced motility. The EC958_1546 gene encodes a phage protein with similarity to esterase/deacetylase enzymes involved in the hydrolysis of sialic acid derivatives found in human mucus. We showed that over-expression of EC958_1546 led to enhanced motility of EC958 as well as the UPEC strains CFT073 and UTI89, demonstrating its activity affects the motility of different UPEC strains. Overall, this study has identified and characterised a number of novel factors associated with enhanced UPEC motility.
Formatted abstract
Uropathogenic Escherichia coli (UPEC) is the cause of ~75% of all urinary tract infections (UTIs) and is increasingly associated with multidrug resistance. This includes UPEC strains from the recently emerged and globally disseminated sequence type 131 (ST131), which is now the dominant fluoroquinolone-resistant UPEC clone worldwide. Most ST131 strains are motile and produce H4-type flagella. Here, we applied a combination of saturated Tn5 mutagenesis and transposon directed insertion site sequencing (TraDIS) as a high throughput genetic screen and identified 30 genes associated with enhanced motility of the reference ST131 strain EC958. This included 12 genes that repress motility of E. coli K-12, four of which (lrhA, ihfA, ydiV, lrp) were confirmed in EC958. Other genes represented novel factors that impact motility, and we focused our investigation on characterisation of the mprA, hemK and yjeA genes. Mutation of each of these genes in EC958 led to increased transcription of flagellar genes (flhD and fliC), increased expression of the FliC flagellin, enhanced flagella synthesis and a hyper-motile phenotype. Complementation restored all of these properties to wild-type level. We also identified Tn5 insertions in several intergenic regions (IGRs) on the EC958 chromosome that were associated with enhanced motility; this included flhDC and EC958-1546. In both of these cases, the Tn5 insertions were associated with increased transcription of the downstream gene(s), which resulted in enhanced motility. The EC958-1546 gene encodes a phage protein with similarity to esterase/deacetylase enzymes involved in the hydrolysis of sialic acid derivatives found in human mucus. We showed that over-expression of EC958-1546 led to enhanced motility of EC958 as well as the UPEC strains CFT073 and UTI89, demonstrating its activity affects the motility of different UPEC strains. Overall, this study has identified and characterised a number of novel factors associated with enhanced UPEC motility.
Keyword Elongation-Factor-P
Differential Expression Analysis
Gram-Negative Bacteria
Regulator-C Qsebc
Urinary-Tract
Multidrug-Resistance
Antibiotic-Resistance
Flagellar Expression
Swarming Motility
Biofilm Formation
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Australian Centre for Ecogenomics
School of Chemistry and Molecular Biosciences
 
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