scholarly journals A new plasmid carrying mphA causes prevalence of azithromycin resistance in enterotoxigenic Escherichia coli serogroup O6

2020 ◽  
Author(s):  
Ying Xiang ◽  
Feng Wu ◽  
Yinghui Chai ◽  
Lang Yang ◽  
Sai Tian ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Control Measure ◽  
Enterotoxigenic Escherichia Coli ◽  
Surveillance Network ◽  
Severe Diarrhea ◽  
Coverage Analysis ◽  
Rapid Spread ◽  
Resistant Strains ◽  
And Control ◽  
Azithromycin Resistance

Abstract Background: At present, azithromycin has become an effective treatment for severe diarrhea caused by Enterotoxigenic Escherichia coli (ETEC) infection. However, enterobacteria have begun to develop resistance to azithromycin and have attracted attention in recent years. This study conducted to described the emergence of a high proportion of azithromycin-resistant ETEC serogroup O6 strains in Shanghai and to analyzed the mechanisms of azithromycin resistance.Results: Strains from adult diarrhea patients with ETEC serogroup O6 infections were collected by Shanghai Diarrhea Surveillance Network and the Foodborne Surveillance Network from 2016 to 2018. We tested 30 isolates of ETEC O6 serogroup, 26 of which were resistant to azithromycin. Phylogenetic analysis revealed that these ETEC serogroup O6 strains have formed an independent dominant clone. S1-PFGE and southern blotting revealed the presence of the mphA gene on the 103kb plasmid. Illumina and Nanopore sequencing and plasmid coverage analysis further confirmed that azithromycin-resistant strains carried a novel IncFII plasmid harboring mphA and blaTEM-1 resistance genes.Conclusions: This is the first study to report a high proportion of azithromycin resistance in a particular ETEC serogroup due to a specific plasmid carrying mphA. Our findings indicate the rapid spread of azithromycin resistance, highlighting the urgency of stringent surveillance and control measure.

scholarly journals A Tripartite Fusion, FaeG-FedF-LT192A2:B, of Enterotoxigenic Escherichia coli (ETEC) Elicits Antibodies That Neutralize Cholera Toxin, Inhibit Adherence of K88 (F4) and F18 Fimbriae, and Protect Pigs against K88ac/Heat-Labile Toxin Infection

2011 ◽  
Vol 18 (10) ◽  
pp. 1593-1599 ◽  
Author(s):  
Xiaosai Ruan ◽  
Mei Liu ◽  
Thomas A. Casey ◽  
Weiping Zhang
Keyword(s):  
Escherichia Coli ◽  
Cholera Toxin ◽  
Enterotoxigenic Escherichia Coli ◽  
Content Type ◽  
Etec Strain ◽  
Severe Diarrhea ◽  
Heat Stable ◽  
Heat Labile ◽  
Young Pigs ◽  
Gnotobiotic Piglet

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) strains expressing K88 (F4) or F18 fimbriae and heat-labile (LT) and/or heat-stable (ST) toxins are the major cause of diarrhea in young pigs. Effective vaccines inducing antiadhesin (anti-K88 and anti-F18) and antitoxin (anti-LT and anti-ST) immunity would provide broad protection to young pigs against ETEC. In this study, we genetically fused nucleotides coding for peptides from K88ac major subunit FaeG, F18 minor subunit FedF, and LT toxoid (LT192) A2 and B subunits for a tripartite adhesin-adhesin-toxoid fusion (FaeG-FedF-LT192A2:B). This fusion was used for immunizations in mice and pigs to assess the induction of antiadhesin and antitoxin antibodies. In addition, protection by the elicited antiadhesin and antitoxin antibodies against a porcine ETEC strain was evaluated in a gnotobiotic piglet challenge model. The data showed that this FaeG-FedF-LT192A2:B fusion elicited anti-K88, anti-F18, and anti-LT antibodies in immunized mice and pigs. In addition, the anti-porcine antibodies elicited neutralized cholera toxin and inhibited adherence against both K88 and F18 fimbriae. Moreover, immunized piglets were protected when challenged with ETEC strain 30302 (K88ac/LT/STb) and did not develop clinical disease. In contrast, all control nonvaccinated piglets developed severe diarrhea and dehydration after being challenged with the same ETEC strain. This study clearly demonstrated that this FaeG-FedF-LT192A2:B fusion antigen elicited antibodies that neutralized LT toxin and inhibited the adherence of K88 and F18 fimbrialE. colistrains and that this fusion could serve as an antigen for vaccines against porcine ETEC diarrhea. In addition, the adhesin-toxoid fusion approach used in this study may provide important information for developing effective vaccines against human ETEC diarrhea.

scholarly journals Passive immunity in cattle against enterotoxigenic Escherichia coli: serologic evaluation of a bacterin containing K99 and F41 fimbriae in colostrum of vaccinated females and calf serum

2004 ◽  
Vol 56 (4) ◽  
pp. 425-432
Author(s):  
H.C.P. Figueiredo ◽  
A.P. Lage ◽  
F.N. Pereira Júnior ◽  
R.C. Leite
Keyword(s):  
Escherichia Coli ◽  
Calf Serum ◽  
Vaccine Dose ◽  
Enterotoxigenic Escherichia Coli ◽  
Passive Immunity ◽  
Control Groups ◽  
Humoral Immune ◽  
Pregnant Females ◽  
Commercial Farms ◽  
And Control

A bacterin from enterotoxigenic Escherichia coli (ETEC), containing fimbriae K99 and F41, was produced and its capacity to induce anti-K99 and anti-F41 antibodies in colostrum of vaccinated cows and in calf serum, and the persistence of these antibodies in neonates were determined. Three experiments were performed on two commercial farms. In all experiments animals were allotted randomly to the blocks, each block consisting of two pregnant females (a vaccinated one and a control one) and their respective calves. In experiment A (farm 1), comprised of 18 blocks, the animals received a vaccine dose 30 days before delivery. In experiment B (farm 1), consisted of 26 blocks, the animals received two vaccine doses (60 and 30 days before delivery). In experiment C (farm 2), consisted of 22 blocks, the animals received two vaccine doses (60 and 30 days before delivery). In experiments A and B pregnant cows and heifers were used and colostrum and serum from 24- to 36-hour-old calves were collected. In experiment C, pregnant embryo-recipient heifers were used and colostrum and sera from calves at 7, 14, 28 and 42 days of age were collected. Anti-K99 and anti-F41 antibodies were detected by ELISA using purified K99 and F41 fimbrial antigens. In experiment A no difference between treated and control groups was observed for the concentration of anti-K99 and anti-F41 antibodies in colostrum and calf serum. In experiment B a difference (P<0.001) was observed for colostrum of vaccinated females and for serum of their calves. In experiment C, difference between vaccinated and control animals was observed for colostrum and calf serum at 7, 14, 28 (P<0.001 in all cases) and 42 days of age (P= 0.003). The results showed the efficiency of the bacterin to induce detectable humoral immune response.

scholarly journals Oral Immunization with a Salmonella typhimurium Vaccine Vector Expressing Recombinant Enterotoxigenic Escherichia coli K99 Fimbriae Elicits Elevated Antibody Titers for Protective Immunity

1998 ◽  
Vol 66 (11) ◽  
pp. 5470-5476 ◽  
Author(s):  
Miguel A. Ascón ◽  
David M. Hone ◽  
Nancy Walters ◽  
David W. Pascual
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Protective Immunity ◽  
Mononuclear Cells ◽  
Immunoglobulin A ◽  
Oral Immunization ◽  
Enterotoxigenic Escherichia Coli ◽  
Effective Vaccine ◽  
Antibody Titers ◽  
And Control

ABSTRACT Bovine enterotoxigenic Escherichia coli (ETEC) continues to cause mortality in piglets and newborn calves. In an effort to develop a safe and effective vaccine for the prevention of F5+ ETEC infections, a balanced lethalasd + plasmid carrying the complete K99 operon was constructed and designated pMAK99-asd +. Introduction of this plasmid into an attenuated Salmonella typhimurium Δaro Δasd strain, H683, resulted in strain AP112, which stably expresses E. coli K99 fimbriae. A single oral immunization of BALB/c and CD-1 mice with strain AP112 elicited significant mucosal immunoglobulin A (IgA) titers that remained elevated for >11 weeks. IgA and IgG responses in serum specific for K99 fimbriae were also induced, with a prominent IgG1, as well as IgG2a and IgG2b, titer. To assess the derivation of these antibodies, a K99 isotype-specific B-cell ELISPOT analysis was conducted by using mononuclear cells from the lamina propria of the small intestines (LP), Peyer’s patches (PP), and spleens of vaccinated and control BALB/c mice. This analysis revealed elevated numbers of K99 fimbria-specific IgA-producing cells in the LP, PP, and spleen, whereas elevated K99 fimbria-specific IgG-producing cells were detected only in the PP and spleen. These antibodies were important for protective immunity. One-day-old neonates from dams orally immunized with AP112 were provided passive protection against oral challenge with wild-type ETEC, in contrast to challenged neonates from unvaccinated dams or from dams vaccinated with a control Salmonella vector. These results confirm that oral Salmonella vaccine vectors effectively deliver K99 fimbriae to mucosal inductive sites for sustained elevation of IgA and IgG antibodies and for eliciting protective immunity.

scholarly journals Expression of Mucin-Type Glycoprotein K88 Receptors Strongly Correlates with Piglet Susceptibility to K88+Enterotoxigenic Escherichia coli, but Adhesion of This Bacterium to Brush Borders Does Not

1998 ◽  
Vol 66 (9) ◽  
pp. 4050-4055 ◽  
Author(s):  
David H. Francis ◽  
Philippe A. Grange ◽  
David H. Zeman ◽  
Diane R. Baker ◽  
Ronggai Sun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Brush Border ◽  
Enterotoxigenic Escherichia Coli ◽  
Poor Correlation ◽  
Biologically Relevant ◽  
Severe Diarrhea ◽  
Brush Borders ◽  
Highly Correlated ◽  
The One

ABSTRACT Three antigenic variants of the K88 fimbrial adhesin exist in nature, K88ab, K88ac, and K88ad. Enterotoxigenic Escherichia coli (ETEC) strains that produce these fimbriae cause life-threatening diarrhea in some but not all young pigs. The susceptibility of pigs to these organisms has been correlated with the adherence of bacteria to isolated enterocyte brush borders. Whether that correlation holds for multiple K88 variants and over a broad genetic base of pigs is unknown and was the impetus for this study. We also desired to examine the correlation of the expression of a porcine intestinal brush border mucin-type glycoprotein (IMTGP) which binds K88ab and K88ac with the susceptibility of piglets to K88+ETEC. Of 31 neonatal gnotobiotic pigs inoculated with K88ab+ or K88ac+ ETEC, 13 developed severe diarrhea, became dehydrated, and died or became moribund. Another pig became severely lethargic but not dehydrated. In vitro brush border adherence analysis was not possible for 10 of the severely ill pigs due to colonization by challenge strains. However, of the 17 pigs that did not become severely ill, 8 (47%) had brush borders that supported the adherence of K88ab+ and K88ac+bacteria in vitro, suggesting a poor correlation between in vitro brush border adherence and piglet susceptibility to K88+ ETEC. By contrast, the expression of IMTGP was highly correlated with susceptibility to K88+ ETEC. Of the 12 pigs that produced IMTGP, 11 developed severe diarrhea. The other pig that produced IMTGP became lethargic but not severely diarrheic. Only 2 of 18 pigs that did not produce IMTGP became severely diarrheic. Colonizing bacteria were observed in histologic sections of intestines from all pigs that expressed IMTGP except for the one that did not develop severe diarrhea. However, colonizing bacteria were observed in histologic sections from only one pig that did not produce IMTGP. The bacterial concentration in the jejuna and ilea of pigs expressing IMTGP was significantly greater (P < 0.005) than that in pigs not expressing IMTGP. These observations suggest the IMTGP is a biologically relevant receptor for K88ab+ and K88ac+ E. coli or a correlate for expression for such a receptor.

scholarly journals Examination of the Enterotoxigenic Escherichia coli Population Structure during Human Infection

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Jason W. Sahl ◽  
Jeticia R. Sistrunk ◽  
Claire M. Fraser ◽  
Erin Hine ◽  
Nabilah Baby ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Comparative Analysis ◽  
Virulence Factor ◽  
Natural Infection ◽  
Population Variation ◽  
Enterotoxigenic Escherichia Coli ◽  
Single Subject ◽  
Content Type ◽  
E Coli ◽  
Severe Diarrhea

ABSTRACT Enterotoxigenic E. coli (ETEC) can cause severe diarrhea and death in children in developing countries; however, bacterial diversity in natural infection is uncharacterized. In this study, we explored the natural population variation of ETEC from individuals with cholera-like diarrhea. Genomic sequencing and comparative analysis of multiple ETEC isolates from twelve cases of severe diarrhea demonstrated clonal populations in the majority of subjects (10/12). In contrast, a minority of individuals (2/12) yielded phylogenomically divergent ETEC isolates. Detailed examination revealed that isolates also differed in virulence factor content. These genomic data suggest that severe, cholera-like ETEC infections are largely caused by a clonal population of organisms within individual patients. Additionally, the isolation of similar clones from geographically and temporally dispersed cases with similar clinical presentations suggests that some isolates are particularly suited for virulence. The identification of multiple genomically diverse isolates with variable virulence factor profiles from a single subject highlights the dynamic nature of ETEC, as well as a potential weakness in the examination of cultures obtained from a single colony in clinical settings. These findings have implications for vaccine design and provide a framework for the study of population variation in other human pathogens. IMPORTANCE Enterotoxigenic Escherichia coli (ETEC) has been identified as one of the major causes of diarrheal diseases in children as well as travelers. It has been previously appreciated that this pathogenic variant of E. coli is diverse, both at the genomic level, as defined with multilocus sequence typing, and with regard to the presence or absence of virulence factors within clonal groups. Using whole-genome sequencing and comparative analysis, we identified and characterized diverse enterotoxigenic E. coli isolates from individual patients. In 17% of patients, we identified multiple distinct ETEC isolates, each with unique genomic features and in some cases diverse virulence factor profiles. These studies ascertained that any one person may be colonized by multiple pathogenic ETEC isolates, which may impact how we think about the development of vaccines and therapeutics against these organisms.

Colonization of the Small Intestine of Weaned Pigs by Enterotoxigenic Escherichia coli that Lack Known Colonization Factors

1992 ◽  
Vol 29 (3) ◽  
pp. 239-246 ◽  
Author(s):  
B. Nagy ◽  
L. H. Arp ◽  
H. W. Moon ◽  
T. A. Casey
Keyword(s):  
Escherichia Coli ◽  
Peyer's Patches ◽  
Enterotoxigenic Escherichia Coli ◽  
Peyer’S Patches ◽  
Bacterial Cells ◽  
Weaned Pigs ◽  
Electron Microscopic ◽  
Etec Strain ◽  
Fimbrial Adhesins ◽  
And Control

Intestinal colonization of 3-week-old weaned pigs by enterotoxigenic Escherichia coli (ETEC) strains that were originally isolated from weaned pigs with fatal diarrhea and that lacked K88, K99, F41, and 987P adhesins (4P− ETEC) was studied by histologic, immunofluorescent, and electron microscopic techniques. In the first experiment, 16 principal pigs were inoculated orogastrically with ETEC strain 2134 (serogroup 0157:H19) or 2171 (serogroup 0141:H4), and eight control pigs were not inoculated. In the second experiment, 24 principals were inoculated with ETEC strain 2134, and 12 controls were inoculated with a nonenterotoxigenic strain of E. coli. Principal and control pigs were necropsied at intervals from 24 to 72 hours after inoculation of principals to provide the tissues used for this report. Results from the two experiments and with both ETEC strains were similar and therefore were combined. Adhesion by 4P″ ETEC was demonstrated in ileum but not in cecum or colon in 22/40 principal pigs sampled at 24 to 72 hours after orogastric inoculation. Adherent bacteria were most apparent on the intestinal villi covering Peyer's patches. Only occasional adherent bacteria were detected in ileal sections from a few (4/20) of the control pigs. Adherence by 4P− ETEC was characterized by “patches” of bacteria closely associated with the lateral surfaces and less frequently with the tips and the bases of intact villi. In most cases, the adherent bacteria were separated from epithelial cell microvilli and other bacterial cells by a 50–400-nm space. Filamentous bacterial appendages bridged this space and formed a network among adjacent bacteria. Colonization of weaned pigs by the 4P− ETEC strains was characterized by preferential adhesion of bacteria to the villi covering Peyer's patches. The filamentous appendages observed between bacteria and microvilli are previously unrecognized fimbrial adhesins, which mediate colonization by these ETEC.

scholarly journals Specificity of Escherichia coli Heat-Labile Enterotoxin Investigated by Single-Site Mutagenesis and Crystallography

2019 ◽  
Vol 20 (3) ◽  
pp. 703 ◽  
Author(s):  
Julie Heggelund ◽  
Joel Heim ◽  
Gregor Bajc ◽  
Vesna Hodnik ◽  
Gregor Anderluh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enterotoxigenic Escherichia Coli ◽  
Resonance Spectroscopy ◽  
Carbohydrate Binding ◽  
Severe Diarrhea ◽  
Heat Labile ◽  
Causes Of Mortality ◽  
Site Mutagenesis ◽  
Toxin Uptake ◽  
Great Burden

Diarrhea caused by enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of mortality in children under five years of age and is a great burden on developing countries. The major virulence factor of the bacterium is the heat-labile enterotoxin (LT), a close homologue of the cholera toxin. The toxins bind to carbohydrate receptors in the gastrointestinal tract, leading to toxin uptake and, ultimately, to severe diarrhea. Previously, LT from human- and porcine-infecting ETEC (hLT and pLT, respectively) were shown to have different carbohydrate-binding specificities, in particular with respect to N-acetyllactosamine-terminating glycosphingolipids. Here, we probed 11 single-residue variants of the heat-labile enterotoxin with surface plasmon resonance spectroscopy and compared the data to the parent toxins. In addition we present a 1.45 Å crystal structure of pLTB in complex with branched lacto-N-neohexaose (Galβ4GlcNAcβ6[Galβ4GlcNAcβ3]Galβ4Glc). The largest difference in binding specificity is caused by mutation of residue 94, which links the primary and secondary binding sites of the toxins. Residue 95 (and to a smaller extent also residues 7 and 18) also contribute, whereas residue 4 shows no effect on monovalent binding of the ligand and may rather be important for multivalent binding and avidity.

scholarly journals The Oral, Live Attenuated Enterotoxigenic Escherichia coli Vaccine ACE527 Reduces the Incidence and Severity of Diarrhea in a Human Challenge Model of Diarrheal Disease

2012 ◽  
Vol 19 (12) ◽  
pp. 1921-1931 ◽  
Author(s):  
Michael J. Darsley ◽  
Subhra Chakraborty ◽  
Barbara DeNearing ◽  
David A. Sack ◽  
Andrea Feller ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ad Hoc ◽  
Diarrheal Disease ◽  
Enterotoxigenic Escherichia Coli ◽  
Content Type ◽  
Severe Diarrhea ◽  
Colonization Factor ◽  
Human Volunteers ◽  
Colonization Factors ◽  
Further Development

ABSTRACTAn oral, live attenuated, three-strain recombinant bacterial vaccine, ACE527, was demonstrated to generate strong immune responses to colonization factor and toxin antigens of enterotoxigenicEscherichia coli(ETEC) in human volunteers. The vaccine was safe and well tolerated at doses of up to 1011CFU, administered in each of two doses given 21 days apart. These observations have now been extended in a phase 2b study with a total of 70 subjects. Fifty-six of these subjects were challenged 28 days after the second dose of vaccine with the highly virulent ETEC strain H10407 to obtain preliminary indicators of efficacy against disease and to support further development of the vaccine for both travelers and infants in countries where ETEC is endemic. The vaccine had a significant impact on intestinal colonization by the challenge strain, as measured by quantitative fecal culture 2 days after challenge, demonstrating the induction of a functional immune response to the CFA/I antigen. The incidence and severity of diarrhea were also reduced in vaccinees as measured by a number of secondary andad hocendpoints, although the 27% reduction seen in the primary endpoint, moderate to severe diarrhea, was not statistically significant. Together, these observations support the hypothesis that the ACE527 vaccine has a dual mode of action, targeting both colonization factors and the heat-labile enterotoxin (LT), and suggest that it should be further developed for more advanced trials to evaluate its impact on the burden of ETEC disease in field settings.

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