Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.110
Filtrar
1.
PLoS Pathog ; 16(8): e1008708, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32785266

RESUMO

The intestinal pathogen Clostridioides difficile exhibits heterogeneity in motility and toxin production. This phenotypic heterogeneity is achieved through phase variation by site-specific recombination via the DNA recombinase RecV, which reversibly inverts the "flagellar switch" upstream of the flgB operon. A recV mutation prevents flagellar switch inversion and results in phenotypically locked strains. The orientation of the flagellar switch influences expression of the flgB operon post-transcription initiation, but the specific molecular mechanism is unknown. Here, we report the isolation and characterization of spontaneous suppressor mutants in the non-motile, non-toxigenic recV flg OFF background that regained motility and toxin production. The restored phenotypes corresponded with increased expression of flagellum and toxin genes. The motile suppressor mutants contained single-nucleotide polymorphisms (SNPs) in rho, which encodes the bacterial transcription terminator Rho factor. Analyses using transcriptional reporters indicate that Rho contributes to heterogeneity in flagellar gene expression by preferentially terminating transcription of flg OFF mRNA within the 5' leader sequence. Additionally, Rho is important for initial colonization of the intestine in a mouse model of infection, which may in part be due to the sporulation and growth defects observed in the rho mutants. Together these data implicate Rho factor as a regulator of gene expression affecting phase variation of important virulence factors of C. difficile.


Assuntos
Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Infecções por Clostridium/microbiologia , Clostridium difficile/metabolismo , Flagelos/metabolismo , Fator Rho/metabolismo , Animais , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Clostridium difficile/genética , Clostridium difficile/patogenicidade , Feminino , Flagelos/genética , Regulação Bacteriana da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óperon , Fator Rho/genética , Virulência
2.
PLoS One ; 15(7): e0236184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32687517

RESUMO

BACKGROUND: Healthcare-associated infections (HAI) are a significant burden on the healthcare system. Recent research has suggested the role of copper in reducing HAI. The purpose of this study was to systematically search literature and pool data from studies evaluating the efficacy of copper-impregnated hospital linen in reducing HAI. METHODS: We carried out a systematic electronic search of PubMed, ScienceDirect, BioMed Central, Springer, Embase, and Google Scholar databases for controlled studies evaluating the efficacy of copper-impregnated linen in reducing the incidence of HAI. The last search was carried out on 15th February 2020. RESULTS: Six studies were included. There was no restriction on the type of organism causing HAI in three studies while three trials reported HAI from Clostridioides difficile and multi-drug resistant organisms (MDRO). A meta-analysis of six studies indicated the use of copper-impregnated linen did not reduce the risk of HAI [Incidence rate ratio (IRR):0.66, 95% CI:0.28-1.58, p = 0.36, I2 = 100%)]. On subgroup analysis, while pooled data from three studies HAI indicated a statistical significant reduction in all-HAI with copper-impregnated linen (IRR:0.76, 95% CI:0.75-0.77, p<0.00001, I2 = 0%), no such difference was seen when HAI was defined as infection by Clostridioides difficile and MDROs only (IRR:0.57, 95% CI:0.12-2.75, p = 0.48, I2 = 99%). Meta-regression analysis for study duration and number of days of hospitalization did not demonstrate any influence on the overall effect size. On sensitivity analysis, there was no change in the significance of results after the sequential exclusion of every study. CONCLUSION: Current evidence on the use of copper-impregnated linen to reduce HAI is conflicting. Our results indicate that copper-impregnated linen may reduce HAI, but there is still no evidence of such an effect regarding infections caused by MDRO or Clostridioides difficile. The overall quality of evidence is not high. Homogenous high-quality studies are required to strengthen the evidence on this subject.


Assuntos
Anti-Infecciosos , Roupas de Cama, Mesa e Banho , Infecções por Clostridium/prevenção & controle , Cobre , Infecção Hospitalar/prevenção & controle , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Clostridium difficile/isolamento & purificação , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla , Humanos , Incidência
3.
Gut ; 69(9): 1555-1563, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32620549

RESUMO

The COVID-19 pandemic has led to an exponential increase in SARS-CoV-2 infections and associated deaths, and represents a significant challenge to healthcare professionals and facilities. Individual countries have taken several prevention and containment actions to control the spread of infection, including measures to guarantee safety of both healthcare professionals and patients who are at increased risk of infection from COVID-19. Faecal microbiota transplantation (FMT) has a well-established role in the treatment of Clostridioides difficile infection. In the time of the pandemic, FMT centres and stool banks are required to adopt a workflow that continues to ensure reliable patient access to FMT while maintaining safety and quality of procedures. In this position paper, based on the best available evidence, worldwide FMT experts provide guidance on issues relating to the impact of COVID-19 on FMT, including patient selection, donor recruitment and selection, stool manufacturing, FMT procedures, patient follow-up and research activities.


Assuntos
Infecções por Clostridium/terapia , Infecções por Coronavirus , Seleção do Doador , Transplante de Microbiota Fecal/métodos , Gastroenterologia , Pandemias , Seleção de Pacientes , Pneumonia Viral , Betacoronavirus , Gestão de Mudança , Infecções por Clostridium/microbiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Gastroenterologia/organização & administração , Gastroenterologia/tendências , Microbioma Gastrointestinal , Humanos , Controle de Infecções/métodos , Controle de Infecções/normas , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Risco Ajustado/métodos , Risco Ajustado/normas
4.
Nat Commun ; 11(1): 3329, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620839

RESUMO

Human gut microbiota plays critical roles in physiology and disease. Our understanding of ecological principles that govern the dynamics and resilience of this highly complex ecosystem remains rudimentary. This knowledge gap becomes more problematic as new approaches to modifying this ecosystem, such as fecal microbiota transplantation (FMT), are being developed as therapeutic interventions. Here we present an ecological framework to understand the efficacy of FMT in treating conditions associated with a disrupted gut microbiota, using the recurrent Clostridioides difficile infection as a prototype disease. This framework predicts several key factors that determine the efficacy of FMT. Moreover, it offers an efficient algorithm for the rational design of personalized probiotic cocktails to decolonize pathogens. We analyze data from both preclinical mouse experiments and a clinical trial of FMT to validate our theoretical framework. The presented results significantly improve our understanding of the ecological principles of FMT and have a positive translational impact on the rational design of general microbiota-based therapeutics.


Assuntos
Infecções por Clostridium/terapia , Transplante de Microbiota Fecal/métodos , Fezes/microbiologia , Microbioma Gastrointestinal/fisiologia , Algoritmos , Animais , Infecções por Clostridium/microbiologia , Clostridium difficile/fisiologia , Humanos , Camundongos , Modelos Teóricos , Recidiva , Resultado do Tratamento
6.
Z Gastroenterol ; 58(5): 456-460, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32392607

RESUMO

Clostridium (C.) ventriculi (known as Sarcina ventriculi) is a ubiquitous gram-positive, anaerobic, acidophilic coccus found in patients with gastric motility disorders. The microorganisms can be identified histologically by their characteristic presentation in tetrads or packets of 8 in hematoxylin and eosin stains. Severe cases of emphysematous gastritis or gastric perforation have been described. Nevertheless, the significance of C. ventriculi in an upper gastrointestinal tract and its pathogenic character remain unclear. We present a 67-year-old woman who underwent hiatoplasty with gastropexy. After 3 months, she underwent a gastroscopy showing gastroesophageal reflux. Biopsies showed ulcerative reflux esophagitis with presence of C.ventriculi, subsequently confirmed by 16S ribosomal RNA gene amplicon sequencing. The barium swallow study revealed an atonic stomach with delayed gastric emptying. The patient was treated with PPI and domperidone. On follow up, 15 months post-operatively, a control gastroscopy showed a stomach with food residues and reflux-associated small erosions. The Clostridium organisms were detected only in oxyntic mucosa biopsies without erosions or ulcerations. We speculate that the recognition of the organisms in the biopsy material is important and suggests dysmotility disorder. However, in our opinion, the presence of C. ventriculi, even in combination with mucosal damage, does not necessarily prompt antibiotic treatment since no complications occurred and inflammation as well as gastric function improved under PPI and prokinetic therapy in our patient. Larger study groups with long-term follow-up are needed to understand whether these organisms could behave as pathogens or are only bystanders in the setting of delayed gastric emptying.


Assuntos
Clostridium/isolamento & purificação , Domperidona/uso terapêutico , Esofagite Péptica/tratamento farmacológico , Esofagite Péptica/microbiologia , Refluxo Gastroesofágico/complicações , Complicações Pós-Operatórias/microbiologia , Idoso , Antibacterianos/uso terapêutico , Antieméticos/uso terapêutico , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/microbiologia , Esofagite Péptica/diagnóstico , Feminino , Refluxo Gastroesofágico/diagnóstico por imagem , Gastropexia , Gastroscopia , Humanos , Inibidores da Bomba de Prótons/uso terapêutico , Estômago/cirurgia
7.
Emerg Infect Dis ; 26(9)2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32441243

RESUMO

We describe 9 patients at a medical center in Detroit, Michigan, USA, with severe acute respiratory syndrome coronavirus 2 and Clostridioides difficile. Both infections can manifest as digestive symptoms and merit screening when assessing patients with diarrhea during the coronavirus disease pandemic. These co-infections also highlight the continued importance of antimicrobial stewardship.


Assuntos
Betacoronavirus , Infecções por Clostridium/epidemiologia , Clostridium difficile , Coinfecção/epidemiologia , Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Adulto , Idoso , Antibacterianos/efeitos adversos , Gestão de Antimicrobianos , Infecções por Clostridium/induzido quimicamente , Infecções por Clostridium/microbiologia , Coinfecção/microbiologia , Infecções por Coronavirus/microbiologia , Feminino , Humanos , Masculino , Michigan/epidemiologia , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/microbiologia , Vigilância da População
8.
BMC Infect Dis ; 20(1): 343, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404060

RESUMO

BACKGROUND: Clostridium difficile infection (CDI) has an increasing pediatric prevalence worldwide. However, molecular characteristics of C. difficile in Chinese children with acute gastroenteritis have not been reported. METHODS: A five-year cross-sectional study was conducted in a tertiary children's hospital in Zhejiang. Consecutive stool specimens from outpatient children with acute gastroenteritis were cultured for C. difficile, and isolates then were analyzed for toxin genes, multi-locus sequence type and antimicrobial resistance. Diarrhea-related viruses were detected, and demographic data were collected. RESULTS: A total of 115 CDI cases (14.3%), and 69 co-infected cases with both viruses and toxigenic C. difficile, were found in the 804 stool samples. The 186 C. difficile isolates included 6 of toxin A-positive/toxin B-positive/binary toxin-positive (A+B+CDT+), 139 of A+B+CDT-, 3 of A-B+CDT+, 36 of A-B+CDT- and 2 of A-B-CDT-. Sequence types 26 (17.7%), 35 (11.3%), 39 (12.4%), 54 (16.7%), and 152 (11.3%) were major genotypes with significant differences among different antimicrobial resistances (Fisher's exact test, P < 0.001). The A-B+ isolates had significantly higher resistance, compared to erythromycin, rifampin, moxifloxacin, and gatifloxacin, than that of the A+B+ (χ2 = 7.78 to 29.26, P < 0.01). The positive CDI rate in infants (16.2%) was significantly higher than that of children over 1 year old (10.8%) (χ2 = 4.39, P = 0.036). CONCLUSIONS: CDI has been revealed as a major cause of acute gastroenteritis in children with various genotypes. The role of toxigenic C. difficile and risk factors of CDI should be emphatically considered in subsequent diarrhea surveillance in children from China.


Assuntos
Infecções por Clostridium/diagnóstico , Infecções por Clostridium/epidemiologia , Clostridium difficile/genética , Diarreia/epidemiologia , Gastroenterite/epidemiologia , Infecções por Vírus de RNA/epidemiologia , Vírus de RNA/genética , Pré-Escolar , China/epidemiologia , Infecções por Clostridium/microbiologia , Coinfecção , Estudos Transversais , Diarreia/virologia , Farmacorresistência Bacteriana , Fezes/virologia , Feminino , Gastroenterite/virologia , Genótipo , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pacientes Ambulatoriais , Infecções por Vírus de RNA/virologia , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco , Centros de Atenção Terciária
9.
Mayo Clin Proc ; 95(4): 758-769, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32247350

RESUMO

Clostridioides difficile infection (CDI) is the leading cause of health care-associated infections in the United States. The increasing incidence and recurrence rates of CDI together with its associated morbidity and mortality are great concerns. Newer treatment methods, such as narrow-spectrum antibiotics, monoclonal antibodies, and microbial replacement therapies, are being developed and implemented. We searched PubMed to identify published literature from 2010 to 2018 using the following keywords: Clostridium difficile, treatment, and therapy. Cited references were also used to identify relevant literature. This review focuses on the current standard of therapy and emerging therapies for CDI and summarizes the updated guidelines on treatment of CDI.


Assuntos
Infecções por Clostridium/terapia , Clostridium difficile , Antibacterianos/uso terapêutico , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/microbiologia , Transplante de Microbiota Fecal , Humanos , Probióticos/uso terapêutico , Recidiva
10.
Transl Res ; 220: 57-67, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32272094

RESUMO

Clostridioides difficile infection (CDI) is an urgent threat to global public health. Patient susceptibility to C. difficile is highly dependent on host immune status and gut dysbiosis resulting in loss of protective microbiota consortia that prevent spore germination, pathogen colonization, and disease pathogenesis. Recent clinical studies highlight the problems of differentiating symptomatic CDI from asymptomatic C. difficile carriage in patients with diarrhea. In this review, we consider how integration of microbiome and host immune systems biology data may aid in the clinical diagnosis of CDI when validated against gold standard testing and combined with standard microbiology laboratory assays.


Assuntos
Infecções por Clostridium/diagnóstico , Biologia de Sistemas/métodos , Infecções por Clostridium/imunologia , Infecções por Clostridium/microbiologia , Microbioma Gastrointestinal , Humanos
11.
Am J Physiol Gastrointest Liver Physiol ; 318(5): G870-G888, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32223302

RESUMO

Clostridioides difficile is an important nosocomial pathogen that produces toxins to cause life-threatening diarrhea and colitis. Toxins bind to epithelial receptors and promote the collapse of the actin cytoskeleton. C. difficile toxin activity is commonly studied in cancer-derived and immortalized cell lines. However, the biological relevance of these models is limited. Moreover, no model is available for examining C. difficile-induced enteritis, an understudied health problem. We hypothesized that human intestinal enteroids (HIEs) express toxin receptors and provide a new model to dissect C. difficile cytotoxicity in the small intestine. We generated biopsy-derived jejunal HIE and Vero cells, which stably express LifeAct-Ruby, a fluorescent label of F-actin, to monitor actin cytoskeleton rearrangement by live-cell microscopy. Imaging analysis revealed that toxins from pathogenic C. difficile strains elicited cell rounding in a strain-dependent manner, and HIEs were tenfold more sensitive to toxin A (TcdA) than toxin B (TcdB). By quantitative PCR, we paradoxically found that HIEs expressed greater quantities of toxin receptor mRNA and yet exhibited decreased sensitivity to toxins when compared with traditionally used cell lines. We reasoned that these differences may be explained by components, such as mucins, that are present in HIEs cultures, that are absent in immortalized cell lines. Addition of human-derived mucin 2 (MUC2) to Vero cells delayed cell rounding, indicating that mucus serves as a barrier to toxin-receptor binding. This work highlights that investigation of C. difficile infection in that HIEs can provide important insights into the intricate interactions between toxins and the human intestinal epithelium.NEW & NOTEWORTHY In this article, we developed a novel model of Clostridioides difficile-induced enteritis using jejunal-derived human intestinal enteroids (HIEs) transduced with fluorescently tagged F-actin. Using live-imaging, we identified that jejunal HIEs express high levels of TcdA and CDT receptors, are more sensitive to TcdA than TcdB, and secrete mucus, which delays toxin-epithelial interactions. This work also optimizes optically clear C. difficile-conditioned media suitable for live-cell imaging.


Assuntos
Infecções por Clostridium/microbiologia , Clostridium difficile/patogenicidade , Enterite/microbiologia , Jejuno/microbiologia , ADP Ribose Transferases/metabolismo , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/microbiologia , Citoesqueleto de Actina/ultraestrutura , Animais , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Forma Celular , Chlorocebus aethiops , Infecções por Clostridium/metabolismo , Infecções por Clostridium/patologia , Clostridium difficile/metabolismo , Enterite/metabolismo , Enterite/patologia , Enterotoxinas/metabolismo , Células HeLa , Interações Hospedeiro-Patógeno , Humanos , Jejuno/metabolismo , Jejuno/ultraestrutura , Mucina-2/metabolismo , Organoides , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Fatores de Tempo , Células Vero , Virulência
12.
Proc Natl Acad Sci U S A ; 117(14): 8064-8073, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32198200

RESUMO

Gastrointestinal infections often induce epithelial damage that must be repaired for optimal gut function. While intestinal stem cells are critical for this regeneration process [R. C. van der Wath, B. S. Gardiner, A. W. Burgess, D. W. Smith, PLoS One 8, e73204 (2013); S. Kozar et al., Cell Stem Cell 13, 626-633 (2013)], how they are impacted by enteric infections remains poorly defined. Here, we investigate infection-mediated damage to the colonic stem cell compartment and how this affects epithelial repair and recovery from infection. Using the pathogen Clostridioides difficile, we show that infection disrupts murine intestinal cellular organization and integrity deep into the epithelium, to expose the otherwise protected stem cell compartment, in a TcdB-mediated process. Exposure and susceptibility of colonic stem cells to intoxication compromises their function during infection, which diminishes their ability to repair the injured epithelium, shown by altered stem cell signaling and a reduction in the growth of colonic organoids from stem cells isolated from infected mice. We also show, using both mouse and human colonic organoids, that TcdB from epidemic ribotype 027 strains does not require Frizzled 1/2/7 binding to elicit this dysfunctional stem cell state. This stem cell dysfunction induces a significant delay in recovery and repair of the intestinal epithelium of up to 2 wk post the infection peak. Our results uncover a mechanism by which an enteric pathogen subverts repair processes by targeting stem cells during infection and preventing epithelial regeneration, which prolongs epithelial barrier impairment and creates an environment in which disease recurrence is likely.


Assuntos
Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Infecções por Clostridium/patologia , Clostridium difficile/patogenicidade , Colo/patologia , Mucosa Intestinal/patologia , Células-Tronco/patologia , Animais , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/toxicidade , Células Cultivadas , Infecções por Clostridium/microbiologia , Clostridium difficile/metabolismo , Colo/citologia , Colo/microbiologia , Modelos Animais de Doenças , Feminino , Receptores Frizzled/genética , Receptores Frizzled/metabolismo , Humanos , Mucosa Intestinal/citologia , Mucosa Intestinal/microbiologia , Camundongos , Organoides , Cultura Primária de Células , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Células-Tronco/microbiologia
13.
Proc Natl Acad Sci U S A ; 117(12): 6792-6800, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32152097

RESUMO

Intestinal bile acids are known to modulate the germination and growth of Clostridioides difficile Here we describe a role for intestinal bile acids in directly binding and neutralizing TcdB toxin, the primary determinant of C. difficile disease. We show that individual primary and secondary bile acids reversibly bind and inhibit TcdB to varying degrees through a mechanism that requires the combined oligopeptide repeats region to which no function has previously been ascribed. We find that bile acids induce TcdB into a compact "balled up" conformation that is no longer able to bind cell surface receptors. Lastly, through a high-throughput screen designed to identify bile acid mimetics we uncovered nonsteroidal small molecule scaffolds that bind and inhibit TcdB through a bile acid-like mechanism. In addition to suggesting a role for bile acids in C. difficile pathogenesis, these findings provide a framework for development of a mechanistic class of C. difficile antitoxins.


Assuntos
Toxinas Bacterianas/química , Toxinas Bacterianas/metabolismo , Ácidos e Sais Biliares/metabolismo , Clostridium difficile/metabolismo , Intestinos/fisiologia , Receptores de Superfície Celular/metabolismo , Células CACO-2 , Infecções por Clostridium/microbiologia , Clostridium difficile/crescimento & desenvolvimento , Células HCT116 , Humanos
14.
PLoS One ; 15(3): e0230475, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32191763

RESUMO

BACKGROUND: Clostridioides difficile Infection (CDI) is a persistent healthcare issue. In the US, CDI is the most common infectious cause of hospital-onset (HO) diarrhea. OBJECTIVE: Assess the impact of admission testing for toxigenic C. difficile colonization on the incidence of HO-CDI. DESIGN: Pragmatic stepped-wedge Infection Control initiative. SETTING: NorthShore University HealthSystem is a four-hospital system near Chicago, IL. PATIENTS: All patients admitted to the four hospitals during the initiative. INTERVENTIONS: From September 2017 through August 2018 we conducted a quality improvement program where admitted patients had a peri-rectal swab tested for toxigenic C. difficile. All colonized patients were placed into contact precautions. MEASUREMENTS: We tested admissions who: i) had been hospitalized within two months, ii) had a past C. difficile positive test, and/or iii) were in a long-term care facility within six months. We measured compliance with all other practices to reduce the incidence of HO-CDI. RESULTS: 30% of admissions were tested and 8.3% were positive. In the year prior to the initiative (Period 1) there were 63,057 admitted patients when HO-CDI incidence was 5.96 cases/10,000 patient days. During the 12-month initiative (Period 2) there were 62,760 admissions and the HO-CDI incidence was 4.23 cases/10,000 patient days (p = 0.02). There were no other practice or antibiotic use changes. Continuing admission surveillance provided a HO-CDI incidence of 2.9 cases/10,000 patient days during the final 9 months of 2018 (p<0.0001 compared to Period 1), equaling <1 case/1,000 admissions. LIMITATIONS: This was not a randomized controlled trial, and multiple prevention practices were in place at the time of the admission surveillance initiative. CONCLUSION: Admission C. difficile surveillance testing is an important tool for preventing hospital-onset C. difficile infection. REGISTRATION: This quality improvement initiative is registered at ClinicalTrials.gov. The unique registration identifier number is NCT04014608.


Assuntos
Infecções por Clostridium/microbiologia , Clostridium difficile/crescimento & desenvolvimento , Hospitalização , Vigilância de Evento Sentinela , Idoso , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Chicago/epidemiologia , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/prevenção & controle , Contagem de Colônia Microbiana , Feminino , Humanos , Incidência , Masculino
15.
J Med Microbiol ; 69(4): 631-639, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32216868

RESUMO

Introduction. Clostridioides difficile is an enteric pathogen that causes a serious toxin-mediated colitis in humans. Bacterial exotoxins and sporulation are critical virulence components that contribute to pathogenesis, and disease transmission and relapse, respectively. Therefore, reducing toxin production and sporulation could significantly minimize C. difficile pathogenicity and disease outcome in affected individuals.Aim. This study investigated the efficacy of a natural flavone glycoside, baicalin, in reducing toxin synthesis, sporulation and spore germination in C. difficile in vitro.Methodology. Hypervirulent C. difficile isolates BAA 1870 or 1803 were cultured in brain heart infusion broth with or without the subinhibitory concentration (SIC) of baicalin, and incubated at 37 °C for 24 h under strictly anaerobic conditions. The supernatant was harvested after 24 h for determining C. difficile toxin production by ELISA. In addition, a similar experiment was performed wherein samples were harvested for assessing total viable counts, and heat-resistant spore counts at 72 h of incubation. Furthermore, C. difficile spore germination and spore outgrowth kinetics, with or without baicalin treatment, was measured in a plate reader by recording optical density at 600 nm. Finally, the effect of baicalin on C. difficile toxin, sporulation and virulence-associated genes was investigated using real-time quantitative PCR.Results. The SIC of baicalin significantly reduced toxin synthesis, sporulation and spore outgrowth when compared to control. In addition, C. difficile genes critical for pathogenesis were significantly down-regulated in the presence of baicalin.Conclusion. Our results suggest that baicalin could potentially be used to control C. difficile, and warrant future studies in vivo.


Assuntos
Antibacterianos/farmacologia , Clostridium difficile/efeitos dos fármacos , Clostridium difficile/patogenicidade , Flavonoides/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções por Clostridium/microbiologia , Clostridium difficile/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Virulência/efeitos dos fármacos
16.
J Vis Exp ; (156)2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32116293

RESUMO

Clostridioides difficile infection (CDI) is considered to be one of the most common healthcare-associated gastrointestinal infections in the United States. The innate immune response against C. difficile has been described, but the exact roles of neutrophils and macrophages in CDI are less understood. In the current study, Danio rerio (zebrafish) larvae are used to establish a C. difficile infection model for imaging the behavior and cooperation of these innate immune cells in vivo. To monitor C. difficile, a labeling protocol using a fluorescent dye has been established. A localized infection is achieved by microinjecting labeled C. difficile, which actively grows in the zebrafish intestinal tract and mimics the intestinal epithelial damage in CDI. However, this direct infection protocol is invasive and causes microscopic wounds, which can affect experimental results. Hence, a more noninvasive microgavage protocol is described here. The method involves delivery of C. difficile cells directly into the intestine of zebrafish larvae by intubation through the open mouth. This infection method closely mimics the natural infection route of C. difficile.


Assuntos
Clostridium difficile/fisiologia , Peixe-Zebra/microbiologia , Animais , Infecções por Clostridium/microbiologia , Clostridium difficile/crescimento & desenvolvimento , Modelos Animais de Doenças , Corantes Fluorescentes/química , Vida Livre de Germes , Intestinos/microbiologia , Intestinos/patologia , Larva/microbiologia , Esporos Bacterianos/fisiologia
17.
Nat Commun ; 11(1): 598, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001686

RESUMO

Metronidazole was until recently used as a first-line treatment for potentially life-threatening Clostridioides difficile (CD) infection. Although cases of metronidazole resistance have been documented, no clear mechanism for metronidazole resistance or a role for plasmids in antimicrobial resistance has been described for CD. Here, we report genome sequences of seven susceptible and sixteen resistant CD isolates from human and animal sources, including isolates from a patient with recurrent CD infection by a PCR ribotype (RT) 020 strain, which developed resistance to metronidazole over the course of treatment (minimal inhibitory concentration [MIC] = 8 mg L-1). Metronidazole resistance correlates with the presence of a 7-kb plasmid, pCD-METRO. pCD-METRO is present in toxigenic and non-toxigenic resistant (n = 23), but not susceptible (n = 563), isolates from multiple countries. Introduction of a pCD-METRO-derived vector into a susceptible strain increases the MIC 25-fold. Our finding of plasmid-mediated resistance can impact diagnostics and treatment of CD infections.


Assuntos
Clostridium difficile/fisiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Metronidazol/farmacologia , Plasmídeos/genética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/microbiologia , Clostridium difficile/efeitos dos fármacos , Clostridium difficile/genética , Clostridium difficile/crescimento & desenvolvimento , DNA Bacteriano/genética , Farmacorresistência Bacteriana/genética , Fezes/microbiologia , Dosagem de Genes , Transferência Genética Horizontal/genética , Humanos , Metronidazol/uso terapêutico , Polimorfismo de Nucleotídeo Único/genética , Replicon/genética
18.
Emerg Microbes Infect ; 9(1): 341-347, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32037964

RESUMO

Clostridioides difficile infection (CDI) is the most prevalent healthcare-associated infection in the United States and carries a significant healthcare system burden. As part of an ongoing, active surveillance system of C. difficile throughout Texas, the objective of this study was to assess changes in C. difficile ribotypes of clinical isolates obtained from hospitalized patients in Texas over the past seven years. Fifty hospitals located in Texas, USA sent C. difficile positive stool specimens to a centralized laboratory for PCR ribotyping and toxin characterization between 2011 and 2018. Data collected included specimen collection date, patient age, and sex. Strain genotypes were compiled, and changes in ribotype distribution over time were assessed. Overall, 7796 samples were ribotyped from predominately female patients (58.4%) aged 62 ± 19 years. Samples were obtained from all geographic regions of Texas including Houston/Southwest region (n = 5129; 85%), Dallas/North Texas (n = 579, 9.6%), Central Texas (n = 164; 2.7%), and South Texas (n = 162; 2.6%). The 10 most common ribotypes comprised 73% of all isolates tested during the study period. The most common ribotypes were 027 (17.5%), followed by 014-020 (16.1%), 106 (11.6%), and 002 (9.1%). The prevalence of ribotypes 027, 001, and 078-126 declined significantly over time, while ribotypes 106 and 054 increased in prevalence (P < 0.001). Furthermore, the emergence of a novel ribotype 255 strain was observed. Differences in ribotype distribution were also noted based on age and geographic distribution (P < 0.001, each). This seven-year study demonstrated changing molecular epidemiology of C. difficile in Texas, including the emergence of a novel ribotype 255.


Assuntos
Infecções por Clostridium/microbiologia , Clostridium difficile/classificação , Ribotipagem , Adulto , Idoso , Técnicas de Tipagem Bacteriana , Infecções por Clostridium/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Reação em Cadeia da Polimerase , Prevalência , Texas
19.
Nat Microbiol ; 5(4): 642-650, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32042128

RESUMO

Although Clostridium difficile is widely considered an antibiotic- and hospital-associated pathogen, recent evidence indicates that this is an insufficient depiction of the risks and reservoirs. A common thread that links all major risk factors of infection is their association with gastrointestinal disturbances, but this relationship to C. difficile colonization has never been tested directly. Here, we show that disturbances caused by diarrhoeal events trigger susceptibility to C. difficile colonization. Using survey data of the human gut microbiome, we detected C. difficile colonization and blooms in people recovering from food poisoning and Vibrio cholerae infections. Carriers remained colonized for year-long time scales and experienced highly variable patterns of C. difficile abundance, where increased shedding over short periods of 1-2 d interrupted week-long periods in which C. difficile was undetectable. Given that short shedding events were often linked to gastrointestinal disturbances, our results help explain why C. difficile is frequently detected as a co-infecting pathogen in patients with diarrhoea. To directly test the impact of diarrhoea on susceptibility to colonization, we developed a mouse model of variable disturbance intensity, which allowed us to monitor colonization in the absence of disease. As mice exposed to avirulent C. difficile spores ingested increasing quantities of laxatives, more individuals experienced C. difficile blooms. Our results indicate that the likelihood of colonization is highest in the days immediately following acute disturbances, suggesting that this could be an important window during which transmission could be interrupted and the incidence of infection lowered.


Assuntos
Infecções por Clostridium/microbiologia , Clostridium difficile/efeitos dos fármacos , Clostridium difficile/patogenicidade , Diarreia/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Laxantes/efeitos adversos , Polietilenoglicóis/efeitos adversos , Actinobacteria/genética , Actinobacteria/crescimento & desenvolvimento , Actinobacteria/isolamento & purificação , Animais , Bacteroidetes/genética , Bacteroidetes/crescimento & desenvolvimento , Bacteroidetes/isolamento & purificação , Infecções por Clostridium/complicações , Clostridium difficile/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Diarreia/induzido quimicamente , Diarreia/complicações , Modelos Animais de Doenças , Fezes/microbiologia , Firmicutes/genética , Firmicutes/crescimento & desenvolvimento , Firmicutes/isolamento & purificação , Fusobactérias/genética , Fusobactérias/crescimento & desenvolvimento , Fusobactérias/isolamento & purificação , Humanos , Masculino , Camundongos , Proteobactérias/genética , Proteobactérias/crescimento & desenvolvimento , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA