Dataset Information

Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine.

ABSTRACT:

Background

Uropathogenic strains of Escherichia coli cause symptomatic infections whereas asymptomatic bacteriuria (ABU) strains are well adapted for growth in the human urinary tract, where they establish long-term bacteriuria. Human urine is a very complex growth medium that could be perceived by certain bacteria as a stressful environment. To investigate a possible imbalance between endogenous oxidative response and antioxidant mechanisms, lipid oxidative damage estimated as thiobarbituric acid reactive substances (TBARS) content was evaluated in twenty-one E. coli belonging to various pathovars and phylogenetic groups. Antioxidant defense mechanisms were also analysed.

Results

During exponential growth in urine, TBARS level differs between strains, without correlation with the ability to grow in urine which was similarly limited for commensal, ABU and uropathogenic strains. In addition, no correlation between TBARS level and the phylogroup or pathogenic group is apparent. The growth of ABU strain 83972 was associated with a high level of TBARS and more active antioxidant defenses that reduce the imbalance.

Conclusions

Our results indicate that growth capacity in urine is not a property of ABU strains. However, E. coli isolates respond very differently to this stressful environment. In strain ABU 83972, on one hand, the increased level of endogenous reactive oxygen species may be responsible for adaptive mutations. On the other hand, a more active antioxidant defense system could increase the capacity to colonize the bladder.

SUBMITTER: Aubron C

PROVIDER: S-EPMC3479029 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Publications

Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine.

Aubron Cecile C Glodt Jeremy J Matar Corine C Huet Olivier O Borderie Didier D Dobrindt Ulrich U Duranteau Jacques J Denamur Erick E Conti Marc M Bouvet Odile O

BMC microbiology 20120622

<h4>Background</h4>Uropathogenic strains of Escherichia coli cause symptomatic infections whereas asymptomatic bacteriuria (ABU) strains are well adapted for growth in the human urinary tract, where they establish long-term bacteriuria. Human urine is a very complex growth medium that could be perceived by certain bacteria as a stressful environment. To investigate a possible imbalance between endogenous oxidative response and antioxidant mechanisms, lipid oxidative damage estimated as thiobarbi ...[more]

PMID: 22727065

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Project description:Enteropathogenic Escherichia coli (EPEC) bacteria are a diverse group of pathogens that cause moderate to severe diarrhea in young children in developing countries. EPEC isolates can be further subclassified as typical EPEC (tEPEC) isolates that contain the bundle-forming pilus (BFP) or as atypical EPEC (aEPEC) isolates that do not contain BFP. Comparative genomics studies have recently highlighted the considerable genomic diversity among EPEC isolates. In the current study, we used RNA sequencing (RNA-Seq) to characterize the global transcriptomes of eight tEPEC isolates representing the identified genomic diversity, as well as one aEPEC isolate. The global transcriptomes were determined for the EPEC isolates under conditions of laboratory growth that are known to induce expression of virulence-associated genes. The findings demonstrate that unique genes of EPEC isolates from diverse phylogenomic lineages contribute to variation in their global transcriptomes. There were also phylogroup-specific differences in the global transcriptomes, including genes involved in iron acquisition, which had significant differential expression in the EPEC isolates belonging to phylogroup B2. Also, three EPEC isolates from the same phylogenomic lineage (EPEC8) had greater levels of similarity in their genomic content and exhibited greater similarities in their global transcriptomes than EPEC from other lineages; however, even among closely related isolates there were isolate-specific differences among their transcriptomes. These findings highlight the transcriptional variability that correlates with the previously unappreciated genomic diversity of EPEC. IMPORTANCE Recent studies have demonstrated that there is considerable genomic diversity among EPEC isolates; however, it is unknown if this genomic diversity leads to differences in their global transcription. This study used RNA-Seq to compare the global transcriptomes of EPEC isolates from diverse phylogenomic lineages. We demonstrate that there are lineage- and isolate-specific differences in the transcriptomes of genomically diverse EPEC isolates during growth under in vitro virulence-inducing conditions. This study addressed biological variation among isolates of a single pathovar in an effort to demonstrate that while each of these isolates is considered an EPEC isolate, there is significant transcriptional diversity among members of this pathovar. Future studies should consider whether this previously undescribed transcriptional variation may play a significant role in isolate-specific variability of EPEC clinical presentations.

Dataset Information

Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine.

Background

Results

Conclusions

Publications

Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine.

Similar Datasets

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