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Identification of toxemia in patients with Clostridium difficile infection.

Yu H, Chen K, Wu J, Yang Z, Shi L, Barlow LL, Aronoff DM, Garey KW, Savidge TC, von Rosenvinge EC, Kelly CP, Feng H - PLoS ONE (2015)

Bottom Line: C. difficile toxins in serum from patients were tested using an ultrasensitive cell-based assay and further confirmed by Rac1 glucosylation assay.Toxins were relatively stable in stored sera.Neutralizing anti-toxin antibodies were present during infection and positively correlated with the diagnosis limits.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America.

ABSTRACT
Toxemia can develop in Clostridium difficile-infected animals, and correlates with severe and fulminant disease outcomes. Circumstantial evidence suggests that toxemia may occur in patients with C. difficile infection (CDI), but positive diagnosis is extremely rare. We analyzed the potential for C. difficile toxemia in patients, determined its characteristics, and assessed challenges. C. difficile toxins in serum from patients were tested using an ultrasensitive cell-based assay and further confirmed by Rac1 glucosylation assay. The factors that hinder a diagnosis of toxemia were assessed, including investigation of toxin stability, the level of toxins-specific neutralizing antibodies in sera and its effect on diagnosis limits. CDI patients develop detectable toxemia in some cases (2.3%). Toxins were relatively stable in stored sera. Neutralizing anti-toxin antibodies were present during infection and positively correlated with the diagnosis limits. Thus, the masking effect of toxin-specific neutralizing antibodies is the major obstacle in diagnosing C. difficile toxemia using cell-based bioassays.

No MeSH data available.


Related in: MedlinePlus

Correlation of neutralizing antibody with detection limit of toxins in toxin-spiked sera from CDI patients.Randomly chose toxemia-negative serum samples were categorized into 3 groups based on levels of neutralizing antibodies (high titer, >80; medium titer, 20<X≤80; low titer, ≤20). Toxin-spiked, toxemia-negative sera were added to mRG1-1 (A) or Vero (B) cells and cell rounding was monitored. (C) A linear correlation assay was performed to show correlations of neutralizing titers with the minimum detectable concentrations of TcdA (left) or TcdB (right), n = 23.
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pone.0124235.g005: Correlation of neutralizing antibody with detection limit of toxins in toxin-spiked sera from CDI patients.Randomly chose toxemia-negative serum samples were categorized into 3 groups based on levels of neutralizing antibodies (high titer, >80; medium titer, 20<X≤80; low titer, ≤20). Toxin-spiked, toxemia-negative sera were added to mRG1-1 (A) or Vero (B) cells and cell rounding was monitored. (C) A linear correlation assay was performed to show correlations of neutralizing titers with the minimum detectable concentrations of TcdA (left) or TcdB (right), n = 23.

Mentions: To determine whether the presence of neutralizing antibodies against the toxins affects the detection of toxemia, we randomly assessed the minimum detectable concentrations of toxins in toxin-spiked serum samples. As the titer of neutralizing antibodies increased, the minimum detectable concentrations of the toxins also elevated (Fig 5A and 5B). A linear regression analysis showed that the neutralizing antibody levels are significantly correlated with the minimum detectable concentrations of toxins in the toxin-spiked serum samples from CDI patients (for TcdA, r2 = 0.82, p< 0.0001; for TcdB, r2 = 0.54, p< 0.0001) (Fig 5C). These data indicate that higher concentrations of toxins are necessary to confer a positive test for toxemia when higher titers of antitoxin neutralizing antibodies were present in patient serum.


Identification of toxemia in patients with Clostridium difficile infection.

Yu H, Chen K, Wu J, Yang Z, Shi L, Barlow LL, Aronoff DM, Garey KW, Savidge TC, von Rosenvinge EC, Kelly CP, Feng H - PLoS ONE (2015)

Correlation of neutralizing antibody with detection limit of toxins in toxin-spiked sera from CDI patients.Randomly chose toxemia-negative serum samples were categorized into 3 groups based on levels of neutralizing antibodies (high titer, >80; medium titer, 20<X≤80; low titer, ≤20). Toxin-spiked, toxemia-negative sera were added to mRG1-1 (A) or Vero (B) cells and cell rounding was monitored. (C) A linear correlation assay was performed to show correlations of neutralizing titers with the minimum detectable concentrations of TcdA (left) or TcdB (right), n = 23.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401762&req=5

pone.0124235.g005: Correlation of neutralizing antibody with detection limit of toxins in toxin-spiked sera from CDI patients.Randomly chose toxemia-negative serum samples were categorized into 3 groups based on levels of neutralizing antibodies (high titer, >80; medium titer, 20<X≤80; low titer, ≤20). Toxin-spiked, toxemia-negative sera were added to mRG1-1 (A) or Vero (B) cells and cell rounding was monitored. (C) A linear correlation assay was performed to show correlations of neutralizing titers with the minimum detectable concentrations of TcdA (left) or TcdB (right), n = 23.
Mentions: To determine whether the presence of neutralizing antibodies against the toxins affects the detection of toxemia, we randomly assessed the minimum detectable concentrations of toxins in toxin-spiked serum samples. As the titer of neutralizing antibodies increased, the minimum detectable concentrations of the toxins also elevated (Fig 5A and 5B). A linear regression analysis showed that the neutralizing antibody levels are significantly correlated with the minimum detectable concentrations of toxins in the toxin-spiked serum samples from CDI patients (for TcdA, r2 = 0.82, p< 0.0001; for TcdB, r2 = 0.54, p< 0.0001) (Fig 5C). These data indicate that higher concentrations of toxins are necessary to confer a positive test for toxemia when higher titers of antitoxin neutralizing antibodies were present in patient serum.

Bottom Line: C. difficile toxins in serum from patients were tested using an ultrasensitive cell-based assay and further confirmed by Rac1 glucosylation assay.Toxins were relatively stable in stored sera.Neutralizing anti-toxin antibodies were present during infection and positively correlated with the diagnosis limits.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America.

ABSTRACT
Toxemia can develop in Clostridium difficile-infected animals, and correlates with severe and fulminant disease outcomes. Circumstantial evidence suggests that toxemia may occur in patients with C. difficile infection (CDI), but positive diagnosis is extremely rare. We analyzed the potential for C. difficile toxemia in patients, determined its characteristics, and assessed challenges. C. difficile toxins in serum from patients were tested using an ultrasensitive cell-based assay and further confirmed by Rac1 glucosylation assay. The factors that hinder a diagnosis of toxemia were assessed, including investigation of toxin stability, the level of toxins-specific neutralizing antibodies in sera and its effect on diagnosis limits. CDI patients develop detectable toxemia in some cases (2.3%). Toxins were relatively stable in stored sera. Neutralizing anti-toxin antibodies were present during infection and positively correlated with the diagnosis limits. Thus, the masking effect of toxin-specific neutralizing antibodies is the major obstacle in diagnosing C. difficile toxemia using cell-based bioassays.

No MeSH data available.


Related in: MedlinePlus