Isolation and characterisation of toxin A-negative, toxin B-positive Clostridium difficile in Dublin, Ireland

Drudy, Denise; Harnedy, N.; Fanning, Séamus; O’Mahony, Rebecca; Kyne, Lorraine

doi:10.1111/j.1469-0691.2006.01634.x

Cited by 67 publications

(51 citation statements)

References 38 publications

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“…8B). This finding may provide an explanation for the protective effect of S.b on C. difficile ribotype 017 infection since this strain produces only toxin B (11,47). Quantitative assessment of cell rounding is shown in Fig.…”

Section: Live But Not Heated S Boulardii Significantly Inhibited Cmentioning

confidence: 84%

“…It is quite interesting that S.b had an inhibitory effect against all outbreak-associated C. difficile strains in vivo and in vitro, although the molecular and clinical characteristics of these strains are quite diverse. C. difficile ribotype 017 has been associated with several outbreaks CDI (11,47) and is characterized by a toxin A-negative and toxin B-positive genotype (26). According to a mouse study, antibiotic treatment even promotes spore shedding of C. difficile ribotype 017 and subsequent animal-to-animal transmission (31).…”

Section: Discussionmentioning

confidence: 99%

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ProbioticSaccharomyces boulardiiCNCM I-745 prevents outbreak-associatedClostridium difficile-associated cecal inflammation in hamsters

Koon

et al. 2016

American Journal of Physiology-Gastrointestinal and Liver Physi

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. difficile infection (CDI) is a common debilitating nosocomial infection associated with high mortality. Several CDI outbreaks have been attributed to ribotypes 027, 017, and 078. Clinical and experimental evidence indicates that the nonpathogenic yeast Saccharomyces boulardii CNCM I-745 (S.b) is effective for the prevention of CDI. However, there is no current evidence suggesting this probiotic can protect from CDI caused by outbreak-associated strains. We used established hamster models infected with outbreak-associated C. difficile strains to determine whether oral administration of live or heat-inactivated S.b can prevent cecal tissue damage and inflammation. Hamsters infected with C. difficile strain VPI10463 (ribotype 087) and outbreakassociated strains ribotype 017, 027, and 078 developed severe cecal inflammation with mucosal damage, neutrophil infiltration, edema, increased NF-B phosphorylation, and increased proinflammatory cytokine TNF␣ protein expression. Oral gavage of live, but not heated, S.b starting 5 days before C. difficile infection significantly reduced cecal tissue damage, NF-B phosphorylation, and TNF␣ protein expression caused by infection with all strains. Moreover, S.b-conditioned medium reduced cell rounding caused by filtered supernatants from all C. difficile strains. S.b-conditioned medium also inhibited toxin A-and B-mediated actin cytoskeleton disruption. S.b is effective in preventing C. difficile infection by outbreak-associated via inhibition of the cytotoxic effects of C. difficile toxins. (46). C. difficile is an anaerobic bacterium that produces two toxins -toxin A and toxin B -that mediate diarrhea, inflammation, and apoptosis of the mucosal epithelium in animals and humans (32). The effects of the toxin in target intestinal cells involve inactivation of the Rho family of GTPase, leading to cytoskeletal disorganization, epithelial cell apoptosis, and ultimately cell death (42, 54). C. difficile toxins also stimulate transcription of several proinflammatory genes, including tumor necrosis factor-␣ (TNF␣) (19) and activate transcription factors and mitogen-activated protein kinases involved in their proinflammatory effects (18,25). The mainstream CDI regimen includes the use of metronidazole, vancomycin, and fidaxomicin (55). However, many C. difficileinfected patients may also suffer from recurrent infections (13), while the recent epidemics that also involve new epidemic outbreak-associated strains (29) pose a major medical problem and epidemiological concern. These challenges have been met with a broad range of preventive approaches against CDI, including the use of probiotics, most notably Saccharomyces boulardii (S.b) alone or in combination with established antibiotic treatment (23,24).S.b is a nonpathogenic yeast that represents one of the well-studied probiotics against CDI in both experimental and clinical settings (24,40). Randomized double-blind placebocontrolled clinical trials have shown that S.b CNCM I-745 is an effective probiotic in the prophylaxis of antibi...

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Section: Live But Not Heated S Boulardii Significantly Inhibited Cmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

ProbioticSaccharomyces boulardiiCNCM I-745 prevents outbreak-associatedClostridium difficile-associated cecal inflammation in hamsters

Koon

et al. 2016

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…Wild-type C. difficile UK1 (6,12,15) and C. difficile M68 (15,24,25), C. difficile JSC10 (cspC::ermB) (6), and C. difficile CAA5 (sleC::ermB) were routinely grown in an anaerobic atmosphere (10% H 2 , 5% CO 2 , 85% N 2 ) at 37°C in brain heart infusion agar supplemented with 5 g/liter yeast extract and 0.1% L-cysteine (BHIS). B. subtilis PS533 and B. subtilis FB113 (cwlJ::tet sleB::spc) (26) were a generous gift from Peter Setlow and were routinely grown on Difco sporulation medium (DSM).…”

Section: Bacteria and Strainsmentioning

confidence: 99%

Spore Cortex Hydrolysis Precedes Dipicolinic Acid Release during Clostridium difficile Spore Germination

2015

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Bacterial spore germination is a process whereby a dormant spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant spore. In a host, spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile spore germination proceeds through a novel pathway. Clostridium difficile (a Gram-positive, spore-forming, strict anaerobe) has become a significant threat to antibiotic-treated or immunocompromised hosts. Antibiotics are known to disrupt the colonic microbiota, and this perturbation permits C. difficile colonization (1, 2). Due to the strict anaerobic nature of C. difficile cells, spores are generally thought to be the infectious agent (only the spore can survive for extended periods of time in the aerobic environment outside a host) (3, 4). Because the spore form is noninfectious, spores must germinate to actively growing bacteria which initiate infection (5, 6). Thus, germination by C. difficile spores represents one of earliest steps in the pathogenesis of this organism.Endospore germination has been extensively studied in Bacillus sp. and, more recently, in clostridia (7,8). In the spore core,...

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“…Hızlı sonuç alın-ması ve uygulama kolaylığı nedeniyle pek çok laboratuvarda toksin A ve B varlığını belirleyen ELISA yöntemi kullanılmaktadır (17) . Toksin A negatif, toksin B pozitif suşların da ishal ve kolit nedeni olarak izole edilmesi ve toksin A/B belirlenen olgularda toksin A'nın sadece % 30.7 oranında pozitif olarak tespiti, C.difficile kaynaklı ishal olgularının saptanmasında toksin A ve B tespitinin bir arada yapılmasının önemini ortaya koymakta ve aynı zamanda patogenezde toksin B'nin önemine dikkat çekmektedir (3,8,16) . Bu nedenle, tanı amacıyla toksin varlığının araştırıl-dığı testlerin hem toksin A, hem de toksin B'yi içermesi gerekmektedir.…”

Section: şEkil 2 Aylara Göre Cdifficile Toksin A/b Pozitiflik Oranıunclassified

The Investigation of Frequency of Clostridium difficile Toxin A/B in Stool Samples of Patients with Diarrhea

Lale¹,

Al²,

Fidan³

et al. 2013

ANKEM Derg

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ÖZET Anahtar sözcükler: Clostridium difficile, ishal, toksin SUMMARY The Investigation of Frequency of Clostridium difficile Toxin A/B in Stool Samples of Patients with Diarrhea Clostridium difficile is one of the most important causes of diarrhea associated with antibiotics. Toxigenic strains of C.difficile lead to various clinical symptoms, ranging from asymptomatic colonization to pseudomembranous colitis. The most widely used test for diagnosing C.difficile associated colitis is a test that detects toxins produced by C.difficile in stool samples.In our study, stool samples of 592 patients with diarrhea were studied for prevalence of C.

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Isolation and characterisation of toxin A-negative, toxin B-positive Clostridium difficile in Dublin, Ireland

Cited by 67 publications

References 38 publications

ProbioticSaccharomyces boulardiiCNCM I-745 prevents outbreak-associatedClostridium difficile-associated cecal inflammation in hamsters

ProbioticSaccharomyces boulardiiCNCM I-745 prevents outbreak-associatedClostridium difficile-associated cecal inflammation in hamsters

Spore Cortex Hydrolysis Precedes Dipicolinic Acid Release during Clostridium difficile Spore Germination

The Investigation of Frequency of Clostridium difficile Toxin A/B in Stool Samples of Patients with Diarrhea

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