scholarly journals Different Effects of Six Antibiotics and Ten Traditional Chinese Medicines on Shiga Toxin Expression byEscherichia coliO157:H7

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Mei Ling Chen ◽  
Zhao Hao ◽  
Yuan Tian ◽  
Qi Yao Zhang ◽  
Pei Ji Gao ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Mrna Level ◽  
Sos Response ◽  
Toxin Production ◽  
Expression Level ◽  
Toxin Gene ◽  
Traditional Chinese Medicines ◽  
Mrna Levels ◽  
Chinese Medicines ◽  
E Coli

This study compared the effects of ten types of traditional Chinese medicines (TCMs) and six different antibiotics onE. coliO157:H7 Shiga toxin gene (stx2) mRNA expression level based on real-time PCR and the expression level of Stx toxin using an ELISA quantitative assay. We also compared their effects on the induction of the SOS response. The results clearly indicated that all ten TCMs had negative results in the SOS response induction test, while most TCMs did not increase the levels ofstx2mRNA and the Stx toxin. Some TCMs did increase the mRNA levels of thestx2gene and the Stx toxin level, but their increases were much lower than those caused by antibiotics. With the exception of cefotaxime, the six antibiotics increased the Stx toxin level and increased thestx2gene mRNA level. With the exceptions of cefotaxime and tetracycline, the antibiotics increased the SOS induction response. These results suggest that TCMs may have advantages compared with antibiotics, when treatingE. coliO157:H7; TCMs did not greatly increase Stx toxin production and release.

scholarly journals Enhancement of Shiga Toxin Production in Enterohemorrhagic Escherichia coli Serotype O157:H7 by DNase Colicins

2007 ◽  
Vol 73 (23) ◽  
pp. 7582-7588 ◽  
Author(s):  
Hirono Toshima ◽  
Ayana Yoshimura ◽  
Kentaro Arikawa ◽  
Ayumi Hidaka ◽  
Jun Ogasawara ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Clinical Manifestations ◽  
Fold Increase ◽  
Toxin Production ◽  
Enterohemorrhagic Escherichia Coli ◽  
Mrna Levels ◽  
Rt Pcr ◽  
E Coli ◽  
Reverse Transcription Pcr

ABSTRACT Colicins are proteins produced by and active against several strains of Escherichia coli. Previously we reported that colicinogenic bacteria seemed beneficial in preventing the clinical manifestations of infectious disease caused by enterohemorrhagic E. coli O157 in humans. The inhibitory effects could be due to a decrease in O157 levels and/or pathogenicity. This study investigated the effects of colicinogenic E. coli on the production of Shiga toxin (Stx) by O157. Standard strains of colicinogenic bacteria carrying plasmids for each type of colicin (E3/5/8/9) were used for the study. The O157 strains were cultured in the presence of colicinogenic bacteria or extracted colicins. Compared with results for controls, DNase colicins (E8/9) facilitated an 8- to 64-fold increase in production of Stx2, while RNase colicins (E3/5) suppressed Stx production in only two strains. Stx prophages were induced in synchrony with Stx production. Semiquantitative real-time reverse transcription-PCR (RT-PCR) was then performed to examine SOS gene expression. The RT-PCR results clearly indicated a marked increase in mRNA levels of SOS reaction-associated genes after the addition of DNase colicins. We believe that Stx prophages are induced by the SOS response to DNA damage caused by DNase colicins, thus leading to higher Stx production. These findings suggest that while colicinogenic bacteria can be antagonistic to O157 infection, DNase colicins may enhance Stx production. Thus, colicinogenic flora is likely to be involved in the complex pathogenic pathways of O157 infection, and further investigation should be performed before the use of colicinogenic bacteria as an intervention method.

scholarly journals Psychoactive Drugs Induce the SOS Response and Shiga Toxin Production in Escherichia coli

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 437
Author(s):  
John K. Crane ◽  
Mashal Salehi ◽  
Cassandra L. Alvarado
Keyword(s):  
Shiga Toxin ◽  
Antimicrobial Properties ◽  
Sos Response ◽  
Toxin Production ◽  
Intestinal Microbiome ◽  
Antibiotic Administration ◽  
Psychoactive Drugs ◽  
E Coli ◽  
Antibiotic Drugs ◽  
Shiga Toxin 2

Several classes of non-antibiotic drugs, including psychoactive drugs, proton-pump inhibitors (PPIs), non-steroidal anti-inflammatory drugs (NSAIDs), and others, appear to have strong antimicrobial properties. We considered whether psychoactive drugs induce the SOS response in E. coli bacteria and, consequently, induce Shiga toxins in Shiga-toxigenic E. coli (STEC). We measured the induction of an SOS response using a recA-lacZ E. coli reporter strain, as RecA is an early, reliable, and quantifiable marker for activation of the SOS stress response pathway. We also measured the production and release of Shiga toxin 2 (Stx2) from a classic E. coli O157:H7 strain, derived from a food-borne outbreak due to spinach. Some, but not all, serotonin selective reuptake inhibitors (SSRIs) and antipsychotic drugs induced an SOS response. The use of SSRIs is widespread and increasing; thus, the use of these antidepressants could account for some cases of hemolytic-uremic syndrome due to STEC and is not attributable to antibiotic administration. SSRIs could have detrimental effects on the normal intestinal microbiome in humans. In addition, as SSRIs are resistant to environmental breakdown, they could have effects on microbial communities, including aquatic ecosystems, long after they have left the human body.

scholarly journals Comparison between human and animal isolates of Shiga toxin-producing Escherichia coli O157 from Australia

2002 ◽  
Vol 128 (3) ◽  
pp. 357-362 ◽  
Author(s):  
N. FEGAN ◽  
P. DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Infection ◽  
Pulsed Field Gel Electrophoresis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Animal Population ◽  
E Coli ◽  
Virulence Markers ◽  
Animal Isolates

There is very little human disease associated with enterohaemorrhagic Escherichia coli O157 in Australia even though these organisms are present in the animal population. A group of Australian isolates of E. coli O157:H7 and O157:H- from human and animal sources were tested for the presence of virulence markers and compared by XbaI DNA macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Each of 102 isolates tested contained the gene eae which encodes the E. coli attaching and effacing factor and all but one carried the enterohaemolysin gene, ehxA, found on the EHEC plasmid. The most common Shiga toxin gene carried was stx2c, either alone (16%) or in combination with stx1 (74%) or stx2 (3%). PFGE grouped the isolates based on H serotype and some clusters were source specific. Australian E. coli O157:H7 and H- isolates from human, animal and meat sources carry all the virulence markers associated with EHEC disease in humans therefore other factors must be responsible for the low rates of human infection in Australia.

scholarly journals Molecular analysis of Escherichia coli O157 strains isolated from cattle and pigs by the use of PCR and pulsed-field gel electrophoresis methods

2012 ◽  
Vol 47 (No. 6) ◽  
pp. 149-158 ◽  
Author(s):  
J. Osek ◽  
P. Gallien
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Rflp Analysis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Chromosomal Dna ◽  
E Coli ◽  
Shiga Toxin Genes ◽  
Porcine Origin

Fourteen Escherichia coli O157 strains isolated from cattle and pigs in Poland and in Germany were investigated, using PCR, for the genetic markers associated with Shiga toxin-producing E. coli (STEC). Only two strains, both of cattle origin, were positive for the fliC (H7) gene and could be classified as O157 : H7. Nine isolates had stx shiga toxin genes, either stx1 (1 strain), stx2 (4 isolates) or both (4 strains). The stx2-carrying samples were further subtyped by PCR for the stx2c, stx2d, and stx2e toxin variants. It was shown that all but one stx2-positive bacteria possessed the stx2c Shiga toxin gene type and one stx2 STEC isolate had the stx2d virulence factor sub-type. The eaeA (intimin) gene was found in 9 strains (8 isolates from cattle and one strain from pigs); all of them harboured the genetic marker characteristic of the gamma intimin variant. The translocated intimin receptor (tir) gene was detected in 7 isolates tested and among them only one tir-positive strain was recovered from pigs. The ehly E. coli enterohemolysin gene was amplified in all but one strains obtained from cattle and only in one isolate of porcine origin. The genetic relatedness of the analysed E. coli O157 strains was examined by restriction fragment length polymorphism (RFLP) of chromosomal DNA digested with XbaI. Two distinct but related RFLP pattern clusters were observed: one with 9 strains (8 isolates of bovine origin and one strain obtained from pigs) and the other one comprises the remaining 5 E. coli isolates (4 of porcine origin and one strain recovered from cattle). The results suggest that pigs, besides cattle, may be a reservoir of E. coli O157 strains potentially pathogenic to humans. Moreover, epidemiologically unrelated isolates of the O157 serogroup, recovered from different animal species, showed a clonal relationship as demonstrated by the RFLP analysis.

scholarly journals Effect of camellia sinensis extract on the expression level of transcription factors and cytochrome p450 genes coding phase i drug-metabolizing enzymes

2013 ◽  
Vol 59 (4) ◽  
pp. 45-59
Author(s):  
Anna Bogacz ◽  
Monika Karasiewicz ◽  
Joanna Bartkowiak-Wieczorek ◽  
Marcin Ożarowski ◽  
Agnieszka Seremak-Mrozikiewicz ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Green Tea ◽  
Camellia Sinensis ◽  
Mrna Level ◽  
Green Tea Extract ◽  
Expression Level ◽  
Gene Transcript ◽  
Mrna Levels ◽  
Clinically Significant ◽  
Tea Extract

Abstract Green tea (Camellia sinensis) is widely used as a popular beverage and dietary supplement that can significantly reduce the risk of many diseases. Despite the widespread use of green tea, the data regarding the safety as well as herb-drug interactions are limited. Therefore, the aim of our study was to assess the influence of standardized green tea extract (GTE) containing 61% catechins and 0.1% caffeine on the expression level of rat CYP genes and the corresponding transcription factors expression by realtime PCR. The findings showed that GTE resulted in a significant decrease of CYP2C6 expression level by 68% (p<0.001). In case of CYP3A1 and CYP3A2, the mRNA levels were also reduced by extract but in a lesser degree compared to CYP2C6. Simultaneously the significant increase in the mRNA level of CAR, RXR and GR factors was observed by 54% (p<0.05), 79% (p<0.001) and 23% (p<0.05), respectively after 10 days of green tea extract administration. In addition, there was noted a small increase of CYP1A1 expression level by 21% (p>0.05) was noted. No statistically significant differences were observed for CYP1A2 and CYP2D1/2. In the same study we observed an increase in amount of ARNT gene transcript by 27% (p<0.05) in the long-term use. However, green tea extract showed the ability to stimulate HNF-1α both after 3 and 10 days of treatment by 30% (p<0.05) and 80% (p<0.001), respectively. In contrast, no change was observed in the concentration of HNF-4α cDNA. These results suggest that GTE may change the expression of CYP enzymes, especially CYP2C6 (homologue to human CYP2C9) and may participate in clinically significant interactions with drugs metabolized by these enzymes.

scholarly journals Replication of plasmids derived from Shiga toxin-converting bacteriophages in starved Escherichia coli

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 220-233 ◽  
Author(s):  
Bożena Nejman ◽  
Beata Nadratowska-Wesołowska ◽  
Agnieszka Szalewska-Pałasz ◽  
Alicja Węgrzyn ◽  
Grzegorz Węgrzyn
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Transcriptional Activation ◽  
Stringent Response ◽  
Toxin Production ◽  
Replication Initiation ◽  
Host Cells ◽  
Regulation Of Transcription ◽  
E Coli ◽  
Dna Replication Initiation

The pathogenicity of Shiga toxin-producing Escherichia coli (STEC) depends on the expression of stx genes that are located on lambdoid prophages. Effective toxin production occurs only after prophage induction, and one may presume that replication of the phage genome is important for an increase in the dosage of stx genes, positively influencing their expression. We investigated the replication of plasmids derived from Shiga toxin (Stx)-converting bacteriophages in starved E. coli cells, as starvation conditions may be common in the intestine of infected humans. We found that, unlike plasmids derived from bacteriophage λ, the Shiga toxin phage-derived replicons did not replicate in amino acid-starved relA + and relA − cells (showing the stringent and relaxed responses to starvation, respectively). The presence of the stable fraction of the replication initiator O protein was detected in all tested replicons. However, while ppGpp, the stringent response effector, inhibited the activities of the λ P R promoter and its homologues from Shiga toxin-converting bacteriophages, these promoters, except for λ P R, were only weakly stimulated by the DksA protein. We suggest that this less efficient (relative to λ) positive regulation of transcription responsible for transcriptional activation of the origin contributes to the inhibition of DNA replication initiation of Shiga toxin-converting bacteriophages in starved host cells, even in the absence of ppGpp (as in starved relA − hosts). Possible clinical implications of these results are discussed.

Detection of cytolethal distending toxin and other virulent factors in Escherichia coli samples from animal livestock, retail foods and gastroenteritis human cases in Qatar

2020 ◽  
Author(s):  
Adriana Morales Gómez ◽  
Nilda N. Valenzuela ◽  
Kenlyn E. Peters ◽  
Ahmed Salem ◽  
Ali Sultan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Products ◽  
Cross Sectional Study ◽  
Toxin Gene ◽  
Cytolethal Distending Toxin ◽  
Cross Sectional ◽  
E Coli ◽  
Polymerase Chain ◽  
Retail Food

Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important bacterial pathogens. To better understand the risk of CDT within the food supply and human gastroenteritis patients in Qatar, we investigated the frequency of the CDT gene (cdtB) among Escherichia coli (E. coli) strains recovered from food products, animal livestock, and human gastroenteritis patients. In this cross-sectional study, E. coli isolates were screened for cdtB using polymerase chain reaction (PCR). cdtB positive strains were further examined for E. coli cdtB gene types (cdt I, cdt II, cdt III, cdt IV and cdtV), serotypes O157: H7, and non-O157 Shiga toxin-producing E. coli O26, O45, O103, O111, O121, and O145. Screening for other virulent factors, stx (Shiga toxin gene) and eae (gene that encodes intimin) genes were also performed. The cdtB gene was detected in E. coli isolates sourced from all three groups; animal livestock (17%), retail foods (8%), and human gastroenteritis patients (3%). Although the incidence of cdtB gene harboring E. coli is relatively low among gastroenteritis patients, there is still a risk of infection from animal reservoirs as well as retail food products. Among the three groups, E. coli isolates from humans had the lowest occurrence of cdtB, stx, eae, and O157: H7. Furthermore, we advise implementing monitoring at the food production and preparation level.

scholarly journals Shiga Toxin Gene Loss and Transfer In Vitro and In Vivo during Enterohemorrhagic Escherichia coli O26 Infection in Humans

2007 ◽  
Vol 73 (10) ◽  
pp. 3144-3150 ◽  
Author(s):  
Martina Bielaszewska ◽  
Rita Prager ◽  
Robin Köck ◽  
Alexander Mellmann ◽  
Wenlan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gene Loss ◽  
Pulsed Field Gel Electrophoresis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Toxin Gene ◽  
Shiga Toxins ◽  
E Coli

ABSTRACT Escherichia coli serogroup O26 consists of enterohemorrhagic E. coli (EHEC) and atypical enteropathogenic E. coli (aEPEC). The former produces Shiga toxins (Stx), major determinants of EHEC pathogenicity, encoded by bacteriophages; the latter is Stx negative. We have isolated EHEC O26 from patient stools early in illness and aEPEC O26 from stools later in illness, and vice versa. Intrapatient EHEC and aEPEC isolates had quite similar pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they might have arisen by conversion between the EHEC and aEPEC pathotypes during infection. To test this hypothesis, we asked whether EHEC O26 can lose stx genes and whether aEPEC O26 can be lysogenized with Stx-encoding phages from EHEC O26 in vitro. The stx 2 loss associated with the loss of Stx2-encoding phages occurred in 10% to 14% of colonies tested. Conversely, Stx2- and, to a lesser extent, Stx1-encoding bacteriophages from EHEC O26 lysogenized aEPEC O26 isolates, converting them to EHEC strains. In the lysogens and EHEC O26 donors, Stx2-converting bacteriophages integrated in yecE or wrbA. The loss and gain of Stx-converting bacteriophages diversifies PFGE patterns; this parallels findings of similar but not identical PFGE patterns in the intrapatient EHEC and aEPEC O26 isolates. EHEC O26 and aEPEC O26 thus exist as a dynamic system whose members undergo ephemeral interconversions via loss and gain of Stx-encoding phages to yield different pathotypes. The suggested occurrence of this process in the human intestine has diagnostic, clinical, epidemiological, and evolutionary implications.

scholarly journals A putative microcin amplifies Shiga toxin 2a production ofEscherichia coliO157:H7

2019 ◽  
Author(s):  
Hillary M. Figler ◽  
Lingzi Xiaoli ◽  
Kakolie Banerjee ◽  
Maria Hoffmann ◽  
Kuan Yao ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Treatment Options ◽  
Gene Clusters ◽  
Toxin Production ◽  
Additional Treatment ◽  
Proteinase K ◽  
Gut Microflora ◽  
E Coli

AbstractEscherichia coliO157:H7 is a foodborne pathogen, implicated in various multi-state outbreaks. It encodes Shiga toxin on a prophage, and Shiga toxin production is linked to phage induction. AnE. colistrain, designated 0.1229, was identified that amplified Stx2a production when co-cultured withE. coliO157:H7 strain PA2. Growth of PA2 in 0.1229 cell-free supernatants had a similar effect, even when supernatants were heated to 100°C for 10 min, but not after treatment with Proteinase K. The secreted molecule was shown to use TolC for export and the TonB system for import. The genes sufficient for production of this molecule were localized to a 5.2 kb region of a 12.8 kb plasmid. This region was annotated, identifying hypothetical proteins, a predicted ABC transporter, and a cupin superfamily protein. These genes were identified and shown to be functional in two otherE. colistrains, and bioinformatic analyses identified related gene clusters in similar and distinct bacterial species. These data collectively suggestE. coli0.1229 and otherE. coliproduce a microcin that induces the SOS response in target bacteria. Besides adding to the limited number of microcins known to be produced byE. coli, this study provides an additional mechanism by whichstx2aexpression is increased in response to the gut microflora.ImportanceHow the gut microflora influences the progression of bacterial infections is only beginning to be understood. Antibiotics are counter-indicated forE. coliO157:H7 infections, and therefore treatment options are limited. An increased understanding of how the gut microflora directs O157:H7 virulence gene expression may lead to additional treatment options. This work identifiedE. colithat enhance the production of Shiga toxin by O157:H7, through the secretion of a proposed microcin. This work demonstrates another mechanism by which non-O157E. colistrains may increase Shiga toxin production, and adds to our understanding of microcins, a group of antimicrobials that are less well understood than colicins.

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