Helicobacter pylori(H.pylori)is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide.However,its prevalence varies among different geographic areas,and is influenced by several factor...Helicobacter pylori(H.pylori)is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide.However,its prevalence varies among different geographic areas,and is influenced by several factors.The infection can be acquired by means of oral-oral or fecal-oral transmission,and the pathogen possesses various mechanisms that improve its capacity of mobility,adherence and manipulation of the gastric microenvironment,making possible the colonization of an organ with a highly acidic lumen.In addition,H.pylori presents a large variety of virulence factors that improve its pathogenicity,of which we highlight cytotoxin associated antigen A,vacuolating cytotoxin,duodenal ulcer promoting gene A protein,outer inflammatory protein and gamma-glutamyl transpeptidase.The host immune system,mainly by means of a Th1-polarized response,also plays a crucial role in the infection course.Although most H.pylori-positive individuals remain asymptomatic,the infection predisposes the development of various clinical conditions as peptic ulcers,gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas.Invasive and non-invasive diagnostic methods,each of them with their related advantages and limitations,have been applied in H.pylori detection.Moreover,bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection,and new therapy alternatives are being tested to improve H.pylori eradication.Last but not least,the development of effective vaccines against H.pylori infection have been the aim of several research studies.展开更多
Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradi- cate as P. aeruginosa has developed strong resistance to ...Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradi- cate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing （QS）, a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacte- rial population changes but also could react to envi- ronmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics.展开更多
The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface mi...The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, bio- logical characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.展开更多
Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. py...Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. pylori is the primary cause of peptic ulcers and gastric cancer. In the United States, the annual cost associated with peptic ulcer disease is estimated to be $6 billion and gastric cancer kills over 700000 people per year globally. The prevalence of H. pylori infection remains high (> 50%) in much of the world, although the infection rates are dropping in some developed nations. The drop in H. pylori prevalence could be a double-edged sword, reducing the incidence of gastric diseases while increasing the risk of allergies and esophageal diseases. The list of diseases potentially caused by H. pylori continues to grow; however, mechanistic explanations of how H. pylori could contribute to extragastric diseases lag far behind clinical studies. A number of host factors and H. pylori virulence factors act in concert to determine which individuals are at the highest risk of disease. These include bacterial cytotoxins and polymorphisms in host genes responsible for directing the immune response. This review discusses the latest advances in H. pylori pathogenesis, diagnosis, and treatment. Up-to-date information on correlations between H. pylori and extragastric diseases is also provided.展开更多
文摘Helicobacter pylori(H.pylori)is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide.However,its prevalence varies among different geographic areas,and is influenced by several factors.The infection can be acquired by means of oral-oral or fecal-oral transmission,and the pathogen possesses various mechanisms that improve its capacity of mobility,adherence and manipulation of the gastric microenvironment,making possible the colonization of an organ with a highly acidic lumen.In addition,H.pylori presents a large variety of virulence factors that improve its pathogenicity,of which we highlight cytotoxin associated antigen A,vacuolating cytotoxin,duodenal ulcer promoting gene A protein,outer inflammatory protein and gamma-glutamyl transpeptidase.The host immune system,mainly by means of a Th1-polarized response,also plays a crucial role in the infection course.Although most H.pylori-positive individuals remain asymptomatic,the infection predisposes the development of various clinical conditions as peptic ulcers,gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas.Invasive and non-invasive diagnostic methods,each of them with their related advantages and limitations,have been applied in H.pylori detection.Moreover,bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection,and new therapy alternatives are being tested to improve H.pylori eradication.Last but not least,the development of effective vaccines against H.pylori infection have been the aim of several research studies.
基金This work was funded by the Biomedical Research Council, Agency for Science, Technology and Research （A＇STAR）, Singapore, and by the National Natural Science Foundation of China （Grant No. 31330002）. We apologize to the scientists who made contributionsto the field, but their works have not been cited due to space limitations.
文摘Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradi- cate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing （QS）, a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacte- rial population changes but also could react to envi- ronmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics.
文摘The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, bio- logical characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.
文摘Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. pylori is the primary cause of peptic ulcers and gastric cancer. In the United States, the annual cost associated with peptic ulcer disease is estimated to be $6 billion and gastric cancer kills over 700000 people per year globally. The prevalence of H. pylori infection remains high (> 50%) in much of the world, although the infection rates are dropping in some developed nations. The drop in H. pylori prevalence could be a double-edged sword, reducing the incidence of gastric diseases while increasing the risk of allergies and esophageal diseases. The list of diseases potentially caused by H. pylori continues to grow; however, mechanistic explanations of how H. pylori could contribute to extragastric diseases lag far behind clinical studies. A number of host factors and H. pylori virulence factors act in concert to determine which individuals are at the highest risk of disease. These include bacterial cytotoxins and polymorphisms in host genes responsible for directing the immune response. This review discusses the latest advances in H. pylori pathogenesis, diagnosis, and treatment. Up-to-date information on correlations between H. pylori and extragastric diseases is also provided.
