Balancing cost and benefit: How E. coli cleverly averts disulfide stress caused by cystine

The Bacillus subtilis monothiol bacilliredoxin BrxC (YtxJ) and the Bdr (YpdA) disulfide reductase reduce S-bacillithiolated proteins

The bacterial cytosol is generally a reducing environment with protein cysteine residues maintained in their thiol form. The low molecular weight thiol bacillithiol (BSH) serves as a general thiol reductant, analogous to glutathione, in a wide range of bacterial species. Proteins modified by disulfide bond formation with BSH (S-bacillithiolation) are reduced by the action of bacilliredoxins, BrxA and BrxB. Here, the YtxJ protein is identified as a monothiol bacilliredoxin, renamed BrxC, and is implicated in BSH removal from oxidized cytosolic proteins, including the glyceraldehyde 3-phosphate dehydrogenases GapA and GapB. BrxC can also debacillithiolate the mixed disulfide form of the bacilliredoxin BrxB. Bdr is a thioredoxin reductase-like flavoprotein with bacillithiol-disulfide (BSSB) reductase activity. Here, Bdr is shown to additionally function as a bacilliredoxin reductase. Bdr and BrxB function cooperatively to debacillithiolate OhrR, a transcription factor regulated by S-bacillithiolation on its sole cysteine residue. Collectively, these results expand our understanding of the BSH redox network comprised of three bacilliredoxins and a BSSB reductase that serve to counter the widespread protein S-bacillithiolation that results from conditions of disulfide stress.

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Bacillithiol is the major low molecular weight thiol in Bacillus subtilis.

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Oxidative stress leads to protein S-bacillithiolation.

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BrxC functions as a monothiol class bacilliredoxin.

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The Bdr bacillithiol disulfide reductase is also a bacilliredoxin.

A systematic review and meta-analysis on the prevalence of Escherichia coli and extended-spectrum β-lactamase-producing Escherichia coli in pregnant women

PROPOSE

The aim of the present study was to determine the prevalence of E. coli and extended-spectrum β-lactamase-producing (ESBL) E. coli in pregnant women in a systematic review and meta-analysis study.

METHODS

We searched important databases, including Medline (PubMed), Embase, Scopus, Web of sciences, Cochrane library, Ovid, and CINHAL to retrieve all articles reporting the prevalence of ESBL E. coli in pregnant women that published from January 1990 to June 2020.

RESULTS

The pooled prevalence of E. coli in pregnant women with and without symptoms of UTI after combining 82 studies with a sample size of 33,118 was 29% (29%; %95 CI 23, 36%). The prevalence based on urine, Feacal, and vagina samples was 26% (% 95 CI 19-34%), 77% (% 95 CI 22-98%), and 32% (% 95 CI 17-48%), respectively. Also, 19 studies with a sample size of 9,200 reported ESBL E. coli prevalence in pregnant women. After combining the results of these studies, the pooled prevalence of ESBL E. coli in pregnant women was 34% (34%; %95 CI 24, 43%). The pooled prevalence of E. coli in pregnant women with HIV was 9%(9%; %95 CI 7, 11%).

CONCLUSION

According to the results of this study, the prevalence of E. coli and ESBL E. coli is high in pregnant women. Also, the overuse of antibiotics was higher in European and Asian pregnant women than other continents.