ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Bacterial infections of the small and large intestine are widespread and continue to be topics of active research. Surveys document the importance of diarrheal disease in many settings. Major breakthroughs in the understanding of pathogenic mechanisms (especially the interactions of bacteria and intestinal cells) continue, particularly with respect to shigella, salmonella,Yersiniaspecies, and enteropathogenicEscherichia coli. Pathogenic mechanisms of other bacteria, such as campylobacter and enteroaggregativeE. coli, are not well defined. Vaccines for cholera and typhoid fever are available, and new vaccines are in various stages of development ranging from synthesis of novel constructs to large-scale field trials. Several candidate vaccines are being exploited as carriers of antigens from other pathogens. Extraintestinal complications from salmonella, shigella, campylobacter,Yersiniaspecies, and Shiga toxin–expressingE. coliare receiving much attention. Genomic sequencing of several of these pathogens is underway. The impact of this work is hard to predict, but expectations are high.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Viral gastroenteritis is a major public health problem worldwide, and the number of identified pathogens continuously increases. Investigators have made considerable progress toward understanding both the epidemiology and the mechanisms of virus–cell interactions, host responses, and pathogenesis. A vaccine for the most important pathogen, rotavirus, has been approved by the US Food and Drug Administration, but possible complications have temporarily curbed the use of this vaccine.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Protozoa that infect the gastrointestinal tract include the deadly parasiteEntamoeba histolytica;Giardia lamblia, the most common cause of waterborne disease outbreaks; and the large group of spore-forming parasites that share a green algae symbiont and a predilection for causing chronic diarrhea in immunocompromised persons. Some recent advances in the epidemiology, pathogenesis, diagnosis, and treatment of the diseases caused by these protozoa are discussed in this review.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Helicobacter pylori, a gram-negative, microaerophilic, motile, spiral-shaped bacterium, has been established as the etiologic agent of gastritis and peptic ulcers and is a major risk factor for gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma (MALT). The ability ofH. pylorito cause this spectrum of diseases depends on host, bacterial, and environmental factors. Bacterial factors critical forH. pyloricolonization of the gastric mucosa include urease, flagella, adhesins, and δ-glutamyltranspeptidase. Lipopolysaccharide, urease, and vacuolating cytotoxin are among the factors that allowH. pylorito persist for decades and invoke an intense inflammatory response, leading to damaged host cells. Genes in thecagpathogenicity island also contribute to the inflammatory response by initiating a signal transduction cascade, resulting in interleukin-8 production. Proinflammatory cytokines and a Th-1 cytokine response further exacerbates the inflammation. Products of the enzymes nitric oxide synthase (iNOS) and cyclooxygenase may perturb the balance between gastric epithelial cell apoptosis (ulcer formation) and proliferation (cancer). The host Th-1 response and antibodies directed againstH. pylorido not eliminate the organism, which presents challenges to vaccine development. Vaccines that include urease have shown some promise, but improved adjuvants and animal models should hasten progress in vaccine research.H. pyloriis the most genetically diverse organism known, and the panmictic population structure may contribute to the varying ranges of disease severity produced by different strains. The complete genome sequence of two strains ofH. pylorihas propelled this field forward, and numerous groups are now using genomic, proteomic, and mutagenetic approaches to identify new virulence genes. Discovered only in 1982,H. pyloriis now among the most intensely investigated organisms. This review summarizes recent progress in this rapidly moving field.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Combination antimicrobial therapies for the effective eradication ofHelicobacter pyloriinfection have been identified and are commercially available. Ongoing studies to improve eradication rates are based on modification of currently approved treatments. Management ofH. pyloriinfection now focuses on which patients should be treated and, by extension, which should be tested, because all patients should have a positive test result forH. pyloribefore starting antimicrobial therapy. Peptic ulcer disease was believed to be caused by acid abnormalities until about two decades ago, whenH. pyloriwas successfully cultured; the clinical records of an early proponent of an infectious cause of peptic ulcer disease were recently discovered. The role ofH. pyloriinfection in gastroesophageal disease and in ulcer disease associated with nonsteroidal anti-inflammatory drugs have become intensely investigated topics. Consensus conferences among pediatric physicians are establishing practice guidelines forH. pylorimanagement in children and adolescents.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

New pathogens that cause gastroenteritis in children are being recognized. Even well-recognized pathogens, such asClostridium difficile, may require more extensive testing than was previously thought necessary. Several new tests have emerged that allow for faster identification of these pathogens so that same-day results may be possible. Probiotic therapy has emerged as a novel strategy for the treatment of gastroenteritis. New vaccines against both viral and bacterial causes of gastroenteritis are being developed. The most exciting recent advance in vaccine development may be the creation of edible vaccines.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Infectious diseases of the gastrointestinal tract continue to be an important source of morbidity and mortality. Viruses, bacteria, fungi, and protozoa that infect normal hosts also infect the gastrointestinal tract in immunocompromised hosts. Disease caused by these pathogens may be more severe and more difficult to treat in immunocompromised hosts. In addition, pathogens that rarely cause disease in normal hosts cause significant disease in immunosuppressed hosts. Diagnostic decisions need to take into account expected pathogens and response to therapy. Treatment decisions must be based on the findings of diagnostic procedures; expected pathogens; and recent data suggesting that highly active antiretroviral therapy, with its ability to reconstitute immune function, is an essential component of treatment. This review summarizes the most important developments made in the pathogenesis, clinical presentation, diagnosis, and treatment of gastrointestinal infections in immunocompromised hosts in the past year.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Treatment of gastrointestinal infections continues to be complicated by expanding resistance to antibiotics. This has led to both new antibiotic treatments and to research on alternative therapies. In the case ofClostridium difficilecolitis, interesting preliminary results have been obtained with both probiotic therapy and passive immunization strategies. The newer macrolides were found to be effective for multidrug-resistantSalmonella typhiand safe in the pediatric population. The efficacy of rifaximin, a nonabsorbed antimicrobial agent, was demonstrated in the treatment of travelers diarrhea in Mexico. The benefit of the proteolytic agent bromelain, which degrades enterocyte receptors for enterotoxigenicEscherichia coli, was shown in an experimental model of piglets challenged with this infection after bromelain prophylaxis. The potential value of zinc supplementation in infant diarrhea was shown in a study in India. The recently approved rotavirus vaccine is being withheld because of multiple reported cases of intussusception. Cryptosporidiosis continues to challenge old and new chemotherapeutic agents. The usefulness of paromomycin inCryptosporidiuminfection was shown in both murine and piglet models. The cost effectiveness of prophylaxis for parasitosis in immigrants has been an area of investigation.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The causes of inflammatory bowel disease remain uncertain, but increasing evidence supports roles for two pathogenic processes: genetic susceptibility in the host and an aberrant host response to enteric bacteria. Here, we review studies showing that the pathogenesis of inflammatory bowel disease involves both bacterial agents and genetic susceptibilities. We discuss the roles of known and novel commensal intestinal bacteria in the pathogenesis of inflammatory bowel disease and the various recombinant approaches used to identify these pathogens.

ISSN:0267-1379    

出版商:OVID    

年代:2000

数据来源: OVID