Evaluation of the Cepheid Xpert C. difficile/Epiand Meridian Bioscienceillumigene C. difficile Assays for Detecting Clostridium difficile Ribotype 033 Strains

Clostridium difficilePCR ribotype 033 (RT033) is found in the gastrointestinal tracts of production animals and, occasionally, humans. TheillumigeneC. difficileassay (Meridian Bioscience, Inc.) failed to detect any of 52C. difficileRT033 isolates, while all strains signaled positive for the binary toxin genes but were reported as negative forC. difficileby the XpertC. difficile/Epiassay (Cepheid).

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Characterizations of Clinical Isolates of Clostridium difficile by Toxin Genotypes and by Susceptibility to 12 Antimicrobial Agents, Including Fidaxomicin (OPT-80) and Rifaximin: a Multicenter Study in Taiwan

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00191-12 ◽

2012 ◽

Vol 56 (7) ◽

pp. 3943-3949 ◽

Cited By ~ 34

Author(s):

Chun-Hsing Liao ◽

Wen-Chien Ko ◽

Jang-Jih Lu ◽

Po-Ren Hsueh

Keyword(s):

Clostridium Difficile ◽

Care Setting ◽

Antimicrobial Agents ◽

Teaching Hospitals ◽

Binary Toxin ◽

Content Type ◽

Vancomycin Mics ◽

Major Teaching ◽

Southern Taiwan

ABSTRACTA total of 403 nonduplicate isolates ofClostridium difficilewere collected at three major teaching hospitals representing northern, central, and southern Taiwan from January 2005 to December 2010. Of these 403 isolates, 170 (42.2%) were presumed to be nontoxigenic due to the absence of genes for toxins A or B or binary toxin. The remaining 233 (57.8%) isolates carried toxin A and B genes, and 39 (16.7%) of these also had binary toxin genes. The MIC90of all isolates for fidaxomicin and rifaximin was 0.5 μg/ml (range, ≤0.015 to 0.5 μg/ml) and >128 μg/ml (range, ≤0.015 to >128 μg/ml), respectively. All isolates were susceptible to metronidazole (MIC90of 0.5 μg/ml; range, ≤0.03 to 4 μg/ml). Two isolates had reduced susceptibility to vancomycin (MICs, 4 μg/ml). Only 13.6% of isolates were susceptible to clindamycin (MIC of ≤2 μg/ml). Nonsusceptibility to moxifloxacin (n= 81, 20.1%) was accompanied by single or multiple mutations ingyrAandgyrBgenes in all but eight moxifloxacin-nonsusceptible isolates. Two previously unreportedgyrBmutations might independently confer resistance (MIC, 16 μg/ml), Ser416 to Ala and Glu466 to Lys. Moxifloxacin-resistant isolates were cross-resistant to ciprofloxacin and levofloxacin, but some moxifloxacin-nonsusceptible isolates remained susceptible to gemifloxacin or nemonoxacin at 0.5 μg/ml. This study found the diversity of toxigenic and nontoxigenic strains ofC. difficilein the health care setting in Taiwan. All isolates tested were susceptible to metronidazole and vancomycin. Fidaxomicin exhibited potentin vitroactivity against all isolates tested, while the more than 10% of Taiwanese isolates with rifaximin MICs of ≥128 μg/ml raises concerns.

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Infection with Toxin A-Negative, Toxin B-Negative, Binary Toxin-Positive Clostridium difficile in a Young Patient with Ulcerative Colitis

Journal of Clinical Microbiology ◽

10.1128/jcm.01810-15 ◽

2015 ◽

Vol 53 (11) ◽

pp. 3702-3704 ◽

Cited By ~ 25

Author(s):

Grace O. Androga ◽

Julie Hart ◽

Niki F. Foster ◽

Adrian Charles ◽

David Forbes ◽

...

Keyword(s):

Ulcerative Colitis ◽

Clostridium Difficile ◽

Young Patient ◽

Diagnostic Methods ◽

Binary Toxin ◽

Toxin A ◽

Toxin B ◽

Content Type ◽

Severe Diarrhea ◽

Clinically Significant

Large clostridial toxin-negative, binary toxin-positive (A−B−CDT+) strains ofClostridium difficileare almost never associated with clinically significantC. difficileinfection (CDI), possibly because such strains are not detected by most diagnostic methods. We report the isolation of an A−B−CDT+ribotype 033 (RT033) strain ofC. difficilefrom a young patient with ulcerative colitis and severe diarrhea.

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Frequency of Binary Toxin Genes among Clostridium difficile Strains That Do Not Produce Large Clostridial Toxins

Journal of Clinical Microbiology ◽

10.1128/jcm.41.11.5227-5232.2003 ◽

2003 ◽

Vol 41 (11) ◽

pp. 5227-5232 ◽

Cited By ~ 67

Author(s):

B. Geric ◽

S. Johnson ◽

D. N. Gerding ◽

M. Grabnar ◽

M. Rupnik

Keyword(s):

Clostridium Difficile ◽

Binary Toxin ◽

Toxin Genes

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Comparative Genome Analysis and Global Phylogeny of the Toxin Variant Clostridium difficile PCR Ribotype 017 Reveals the Evolution of Two Independent Sublineages

Journal of Clinical Microbiology ◽

10.1128/jcm.01296-16 ◽

2016 ◽

Vol 55 (3) ◽

pp. 865-876 ◽

Cited By ~ 29

Author(s):

M. D. Cairns ◽

M. D. Preston ◽

C. L. Hall ◽

D. N. Gerding ◽

P. M. Hawkey ◽

...

Keyword(s):

Clostridium Difficile ◽

Antibiotic Resistance Genes ◽

Binary Toxin ◽

Human Origins ◽

Comparative Genome Analysis ◽

Toxin B ◽

Content Type ◽

Global Spread ◽

Animal Isolates ◽

Evolutionary Lineages

ABSTRACT The diarrheal pathogen Clostridium difficile consists of at least six distinct evolutionary lineages. The RT017 lineage is anomalous, as strains only express toxin B, compared to strains from other lineages that produce toxins A and B and, occasionally, binary toxin. Historically, RT017 initially was reported in Asia but now has been reported worldwide. We used whole-genome sequencing and phylogenetic analysis to investigate the patterns of global spread and population structure of 277 RT017 isolates from animal and human origins from six continents, isolated between 1990 and 2013. We reveal two distinct evenly split sublineages (SL1 and SL2) of C. difficile RT017 that contain multiple independent clonal expansions. All 24 animal isolates were contained within SL1 along with human isolates, suggesting potential transmission between animals and humans. Genetic analyses revealed an overrepresentation of antibiotic resistance genes. Phylogeographic analyses show a North American origin for RT017, as has been found for the recently emerged epidemic RT027 lineage. Despite having only one toxin, RT017 strains have evolved in parallel from at least two independent sources and can readily transmit between continents.

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Clostridium difficile Binary Toxin CDT Induces Clustering of the Lipolysis-Stimulated Lipoprotein Receptor into Lipid Rafts

mBio ◽

10.1128/mbio.00244-13 ◽

2013 ◽

Vol 4 (3) ◽

Cited By ~ 29

Author(s):

Panagiotis Papatheodorou ◽

Daniel Hornuss ◽

Thilo Nölke ◽

Sarah Hemmasi ◽

Jan Castonguay ◽

...

Keyword(s):

Plasma Membrane ◽

Clostridium Difficile ◽

Lipid Rafts ◽

Receptor Binding ◽

Binding Domain ◽

Binary Toxin ◽

Lipoprotein Receptor ◽

Receptor Binding Domain ◽

Content Type ◽

Binding Component

ABSTRACT Clostridium difficile is the leading cause of antibiotics-associated diarrhea and pseudomembranous colitis. Hypervirulent C. difficile strains produce the binary actin-ADP-ribosylating toxin CDT (C. difficile transferase), in addition to the Rho-glucosylating toxins A and B. We recently identified the lipolysis-stimulated lipoprotein receptor (LSR) as the host receptor that mediates uptake of CDT into target cells. Here we investigated in H1-HeLa cells, which ectopically express LSR, the influence of CDT on the plasma membrane distribution of the receptor. We found by fluorescence microscopy that the binding component of CDT (CDTb) induces clustering of LSR into subcompartments of the plasma membrane. Detergent extraction of cells treated with CDTb, followed by sucrose gradient fractionation, uncovered accumulation of LSR in detergent-resistant membranes (DRMs) that contained typical marker proteins of lipid rafts. Membrane cholesterol depletion with methyl-β-cyclodextrin inhibited the association of LSR with DRMs upon addition of CDTb. The receptor-binding domain of CDTb also triggered LSR clustering into DRMs. CDTb-triggered clustering of LSR into DRMs could be confirmed in Caco-2 cells. Our data suggest that CDT forces its receptor to cluster into lipid rafts and that oligomerization of the B component might enhance but is not essential for this process. IMPORTANCE C. difficile binary toxin CDT is a member of the iota-like, actin ADP-ribosylating toxin family. The mechanism that mediates endocytic uptake of these toxins still remains elusive. Previous studies highlighted the importance of lipid rafts for oligomerization of the binding component of these toxins and for cell entry. Recently, the host cell receptor for this toxin family, namely, the lipolysis-stimulated lipoprotein receptor (LSR), has been identified. Our study now demonstrates that the binding component of CDT (CDTb) induces clustering of LSR into lipid rafts. Importantly, LSR clustering is efficiently induced also by the receptor-binding domain of CDTb, suggesting that oligomerization of the B component of CDT is not the main trigger of this process. The current work extends our knowledge on the cooperative play between iota-like toxins and their receptor.

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Toxigenic Clostridium difficile PCR Ribotypes from Wastewater Treatment Plants in Southern Switzerland

Applied and Environmental Microbiology ◽

10.1128/aem.01379-12 ◽

2012 ◽

Vol 78 (18) ◽

pp. 6643-6646 ◽

Cited By ~ 40

Author(s):

Vincenza Romano ◽

Vincenzo Pasquale ◽

Karel Krovacek ◽

Federica Mauri ◽

Antonella Demarta ◽

...

Keyword(s):

Wastewater Treatment ◽

Clostridium Difficile ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Treated Wastewater ◽

Binary Toxin ◽

Toxin B ◽

Content Type ◽

Human Infections ◽

Reuse Of Treated Wastewater

ABSTRACTThe occurrence ofClostridium difficilein nine wastewater treatment plants in the Ticino Canton (southern Switzerland) was investigated. The samples were collected from raw sewage influents and from treated effluents. Forty-seven out of 55 characterizedC. difficilestrains belonged to 13 different reference PCR ribotypes (009, 010, 014, 015, 039, 052, 053, 066, 070, 078, 101, 106, and 117), whereas 8 strains did not match any of those available in our libraries. The most frequently isolated ribotype (40%) was 078, isolated from six wastewater treatment plants, whereas ribotype 066, a toxigenic emerging ribotype isolated from patients admitted to hospitals in Europe and Switzerland, was isolated from the outgoing effluent of one plant. The majority of the isolates (85%) were toxigenic. Forty-nine percent of them produced toxin A, toxin B, and the binary toxin (toxigenic profile A+B+CDT+), whereas 51% showed the profile A+B+CDT−. Interestingly, eight ribotypes (010, 014, 015, 039, 066, 078, 101, and 106) were among the riboprofiles isolated from symptomatic patients admitted to the hospitals of the Ticino Canton in 2010. Despite the limitation of sampling, this study highlights that toxigenic ribotypes ofC. difficileinvolved in human infections may occur in both incoming and outgoing biological wastewater treatment plants. Such a finding raises concern about the possible contamination of water bodies that receive wastewater treatment plant effluents and about the safe reuse of treated wastewater.

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Complete Genome Sequence of a Novel Mutant Strain of Vibrio parahaemolyticus from Pacific White Shrimp (Penaeus vannamei)

Genome Announcements ◽

10.1128/genomea.00497-18 ◽

2018 ◽

Vol 6 (24) ◽

Cited By ~ 4

Author(s):

Siddhartha Kanrar ◽

Arun K. Dhar

Keyword(s):

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Vibrio Parahaemolyticus ◽

Pacific White Shrimp ◽

White Shrimp ◽

Binary Toxin ◽

Penaeus Vannamei ◽

Content Type ◽

Toxin Genes

ABSTRACT The acute hepatopancreatic necrosis disease (AHPND) of Penaeus vannamei shrimp is caused by Vibrio parahaemolyticus carrying toxin genes, pirA and pirB. We report the complete genome sequence of the novel V. parahaemolyticus strain R14, which did not display AHPND symptoms in P. vannamei despite containing the binary toxin genes.

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