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BMC Proceedings

Open Access

Competitiveness-enhancing pathogen virulence gene expression and associated inducing molecules in human urine

  • NGD O’Mara1 and
  • MB Prentice2
BMC Proceedings20159(Suppl 1):A21

https://doi.org/10.1186/1753-6561-9-S1-A21

Published: 14 January 2015

Background

The abundance of ethanolamine (EA) and 1,2-propanediol (PD) within the mammalian intestine has recently been hypothesized to provide certain pathogenic bacteria with a niche-specific carbon/nitrogen and energy source and provide a signal to enteric pathogens of their arrival in the small intestine. PD and EA metabolism may enhance competitive advantage for pathogen growth in other body compartments where these compounds are present. Pathogens such as Salmonella, Escherichia coli and Klebsiella utilise ethanolamine, while propanediol usage occurs in Yersinia, Klebsiella, Salmonella and Clostridium [2][3]. These pathogens possess the pdu and/or eut operon(s), which encode the necessary metabolic machinery to utilise PD/EA in addition to a number of virulence genes that may be induced by pdu/eut regulatory genes. In a preliminary study, we detected PD and EA in human urine, demonstrated that urinary pathogens can metabolise these molecules in vitro and observed growth of bacteria possessing pdu/eut operons in human urine.

Methods

Over a 10-month period 70 urine samples were obtained from the Bacteriology laboratory at Cork University Hospital, half of which were from patients with coliform-type urinary tract infections. Gas chromatography and liquid chromatography mass spectrometry methods were used to quantify PD and EA respectively in a cohort of 20 urine samples. Chromogenic media (PD-enriched MacConkey agar) was utilised to demonstrate bacterial PD metabolism in bacteriuric samples. Using a Escherichia coli ECOR library and K. pneumoniae strain (NCIMB 132128), 18-hour kinetic growth studies of known pdu/eut positive bacteria in human urine were performed.

Results

Growth studies revealed that eut/pdu positive bacteria grew well within human urine samples whether or not urine was supplemented with PD and EA. PD was determined to be present in all tested urine samples (n=19, 10 infected, 9 non-infected) in varying concentrations (trace to 8.8mM), while EA was present in much smaller quantities (trace to 0.13mM). PD metabolism was demonstrated in two putative Klebsiella spp. bacteriuric isolates (n=15).

Conclusions

EA and PD are detectable and present within human urine PD is present in larger amounts. PD utilisation is known to occur in a minority of urinary pathogens. Quantitative gene expression studies will be used to seek pdu/eut operon expression from urinary isolates

Authors’ Affiliations

(1)
School of Medicine University College Cork
(2)
Departments of Pathology/Microbiology, University College Cork

References

  1. Garsin D: Ethanolamine utilization in bacterial pathogens: roles and regulation. Nature Reviews Microbiology. 2010, 8 (4): 290-295.View ArticlePubMed CentralPubMedGoogle Scholar
  2. Bobik TA, et al: The propanediol utilization (pdu) operon of Salmonella enterica serovar Typhimurium LT2 includes genes necessary for formation of polyhedral organelles involved in coenzyme B12- dependent 1,2 -propanediol degradation. Journal of Bacteriology. 1999, 181 (19): 5967-5975.PubMed CentralPubMedGoogle Scholar
  3. Bertin Y, et al: EHEC gains a competitive advantage by using ethanolamine as a nitrogen source in the bovine intestinal content. Environmental Microbiology. 2011, 13 (2): 365-77.View ArticlePubMedGoogle Scholar

Copyright

© O’Mara and Prentice; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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