ISSN 1673-6184 CN 31-1966/R
New pathogens have truly emerged with the globalization of travel and trade, changes in demographics and land use, susceptibility to opportunistic organisms associated with immunosuppression, and climate change. The so-called new pathogens can be divided into three categories, the pathogen identified first time in a region or a country, the mutated pathogens with increased virulence and/or infectivity which could not be correctly identified by current methods, and the pathogen emerged for the first time worldwide. The new pathogen in term of a subject should include the basic research, development of technology and strategies to establish the technology and scientific system to define a causal relationship between agent and disease, to understand how it causes disease and to assess the potential threat to public. The subject of new pathogen should interact with many disciplines such as genomics, epidemiology, clinical medicine, computational biology, ecology, animal sciences and others. The new molecular technologies such as microbial microarrays and unbiased high throughput sequencing have enabled efficient microbial surveillance and discovery. The aim of new pathogen study is to improve our ability and capacity to identify, to study, to control the new pathogens with public health significance. With development and progress of theory and methodology, we should be able to correctly identify the pathogen emerged for first time in China, to correctly and timely identify the mutated pathogen with significant public health significance, and to timely find the pathogen emerged for first time in the world.
In order to explore the role of core protein on the replication and infection of hepatitis C virus (HCV), intergenotypic chimeric FL-J6JFH/J4 core replicon was constructed in which the core gene of Fl-J6JFH strain (genotype 2a) was replaced by corresponding gene from HC-J4 strain (1b). In vitro RNA transcripts of FL-J6JFH and FL-J6JFH/J4 core were prepared and transfected into Huh7.5.1 hepatocytes respectively with liposomes. At day 5 post-transfection, total cellular RNA was isolated and determined by fluorescence quantitative polymerase chain reaction (FQ-PCR) method. Immunofluorescence staining analysis was performed to test the expression of HCV proteins in transfected cells at day 8 post-transfection. The naïve Huh7.5.1 cells were inoculated with the supernatants collected at day 8 post-transfection, and HCV proteins were detected by immunofluorescence at 72 h after inoculation. The results demonstrated that, the intracellular HCV RNA values of FL-J6JFH/J4 core was close to that of wild-type FL-J6JFH1 at day 5 post-transfection, and no significant differences were observed (n＝4, P>0.05). Immunofluorecene analysis showed that, as compared with that in the wild type cells, the expression of HCV proteins in either cells transfected with FL-J6JFH/J4 core RNA at day 8 post-transfection or inoculation with supernatants collected at day 8 post-transfection was significantly lower. The results suggest that the core gene substitution among different HCV strains might influence the HCV protein expression and the production of infectious viral particles.
To investigate the interaction between hepatitis C virus core protein (HCV-C) and liver cells, purified HCV-C was obtained and polyclonal antibodies against HCV-C were prepared in the present study. The plasmid containing HC-J4-91 whole genome of HCV1b subtype was used as the template and the HCV-C gene was TA-cloned by polymerase chain reaction (PCR). The prokaryotic expression plasmid containing 6×His and HCV-C gene was constructed and named as pQE31-HCV-C. After expression in Escherichia coli and purification, the recombinant HCV-C was used to immunize BALB/c mice to obtain the antiserum. The titer and specificity of the antibody were determined by enzyme-linked immunosorbent assay (ELISA), Western blot and indirect immunofluorescence staining. The results demonstrated that the prokaryotic expression plasmid pQE31-HCV-C expressing a 22 000 fusion protein was successfully constructed. ELISA showed that antiserum against HCV-C from immunized mice had high antibody level, with titer at 1:12 800. Immunofluorescence staining and Western blot indicated that the antibody had good specificity and could recognize nature and unnatural HCV-C. It is concluded that the purified HCV-C protein and anti-HCV-C polyclonal antibodies obtained in this study might be useful for studying the molecular interaction mechanism between HCV-C and liver cells.
The paper aims to investigate the susceptibility test results of 201 tuberculosis patients in Shanghai Pulmonary Hospital from December 2008 to May 2009. Roche system was used to culture Mycobacterium tuberculosis (M. tuberculosis), and absolute concentration method was used to test drug susceptibility. In 201 patients, the resistance rates of M. tuberculosis were as follows: isoniazid (INH, 52.24%), streptomycin (SM, 45.77%), rifampicin (RFP, 30.35%), ethambutol (EMB, 28.86%), amikacin (AK, 28.18%), rifapentine (RIB, 26.40%), pasiniazide (Pa, 25.56%), paraminosalicylic acid (PAS, 23.60%), protionamide (Pt, 23.03%), capreomycin (CPM, 20.56%). Among all the patiemts, drug resistance rates in initial treated patients was 3.08%~25.87%, in previously treated patients was 27.50%~64.71%, in multi-drug resistant patients was 64.44%~93.10%. Overall, compared with low concentration of drugs, high concentration of SM, INH, EMB, RIB and Pt decreased the resistance rate of M. tuberculosis significantly (P <0.05). Except for INH, SM and RFP, the most drug resistance rates and multi-drug resistance rate in female were significantly higher than those in male (P <0.05). The results suggest that the application of anti-tuberculosis drugs should be adequate clinically, and more attention should be paid to the female patients.
In order to explore the incidence of Clostridium difficile-associated diarrhea(CDAD) among children of diarrhea and to give a retrospective clinical analysis of this kind of diarrhea, we employed an ELISA-based assay of Clostridium difficile toxin A to the stool samples of children with diarrhea from February 2007 to September 2007 in Children’s Hospital of Fudan University. Anaerobic bacteria culture was also performed for each recruited sample. Four cultured Clostridium difficile strains were isolated and subjected to a Multi-Locus VNTR Assay(MLVA) to investigate the epidemiological information. 111 cases were recruited, among which none cases were positive for both toxin A investigation and anaerobic bacteria culturing, 16 cases were toxin A positive while culture negative, 4 cases were toxin A negative while culture positive, and 91 cases were either toxin A positive nor culture positive. The comparison of the incidence of CDAD of different courses between hospital-acquired and community-acquired infection has shown no statistically significant differences(P>0.05). The four cultured Clostridium difficile isolates were found to related to each other to some extent in the phylogenetic tree. In conclusion, the Clostridium difficile infection in Shanghai is sporadic, but may related phylogeneticly to some extent. The clinical manifestation of CDAD is of no specialty than those without evidence of CD infections.
The present paper aims to investigate the prevalence trends, early clinical characteristics and treatment experience of hand, foot and mouth disease complicated with brain injury. The outpatients clinically diagnosed as hand, foot and mouth disease and inpatients with severe hand foot and mouth disease diagnosed by comprehensive analysis in our chilidren’s hospital from August 1, 2008 to July 31, 2009 were chosen. The clinical manifestations, laboratory examination, treatment and outcome data from 43 cases of patients with hand, foot and mouth disease complicated with brain injury were retrospective analyzed. The results showed that hand, foot and mouth disease occurred throughout the year. The incidence of hand, foot and mouth disease complicated with brain injury was 1.57%, which mainly occurred from May to October. The average age of patients was 2.89 years old, with the youngest of 5 months old and the oldest of 13 years old. In clinical classification, brain stem encephalitis accounted for 48.8%, encephalitis accounted for 32.6%, meningoencephalitis accounted for 18.6%. Administration of mannitol, methyl-prednisolone, intravenous gamma globulin, and mechanical ventilation for those precursors of pulmonary edema as early as possible was the main treatment measure. Among the patients, 98% had a good prognosis. The hospital average length of stay was 11.1 d. The survey confirmed that the incidence of hand, foot and mouth disease complicated with brain injury was 1.57%, occurring mainly from May to October, and brain stem encephalitis is common. Early diagnosis, effectively reducing intracranial pressure, rational use of high-dose intravenous gamma globulin and short-term high-dose hormone are effective measures in preventing disease progression.
A rare case of septicemia complicated with meningitis in a child caused by Sphingomonas paucimobilis is reported. The patient was admitted for a sudden high fever with petechiae distributed on the skin. Based on the biochemistry test of cerebrospinal fluid and the microbiological culture and identification in laboratory, the diagnosis was conformed to be septicemia complicated with bacterial meningitis. Meningitis in children caused by Sphingomonas paucimobilis was rare. Since bacterial meningitis cases share common symptoms with epidemic cerebrospinal meningitis, it is important for the clinicians and laboratories to study the etiology carefully during epidemic season.
Pathogenicity island is a gene cluster that have special structure and located in bacterial chromosome,which function is code productions that associated with bacterial virulence and metabolism. Type Ⅳ secretion system（T4SS）is an important export pathway used by Gram-negative pathogenic bacteria to inject bacterial proteins into the cytosol of eukaryotic host cells.Cag and type Ⅳ secretion system coded by cag, a pathogenicity island(PAI) of Helicobacter pylori, were all the key factors to cause diseases. While which was a burning question in related fields recently, and would also be a new target for medical treatment. This review summarized the recent studies on it.
Ureaplasma urealyticum whose pathogenicity is still controversial is a common micro-organisms of female urogenital mucosa.Lower genital tract infection of ureaplasma urealyticum can cause non-gonococcal urethritis or cervicitis mucus, while in the respiratory tract context, Ureaplasma urealyticum can induce neonatal pneumonia, bronchopulmonary dysplasia, chronic lung disease and so on.For the study of pathogenesis of Ureaplasma urealyticum infection, host immune response, as well as development of prevention and treatment of Ureaplasma urealyticum infection in drug experiments, animal model is indispensable.At home and abroad a variety of Ureaplasma urealyticum whose pathogenicity is still controversial is a common micro-organisms of female urogenital mucosa.Lower genital tract infection of ureaplasma urealyticum can cause non-gonococcal urethritis or cervicitis mucus, while in the respiratory tract context, ureaplasma urealyticum can induce neonatal pneumonia, bronchopulmonary dysplasia, chronic lung disease and so on.For the study of pathogenesis of ureaplasma urealyticum infection, host immune response, as well as development of prevention and treatment of ureaplasma urealyticum infection in drug experiments, animal model is indispensable.At home and abroad a variety of Ureaplasma urealyticum animal models have been successfully established.Estradiol pretreatment is essential for the animal model of Ureaplasma urealyticum reproductive tract infection, , and BALB / c mice is the preferred experimental animals, while ureaplasma urealyticum respiratory tract infection model does not need estrogen pretreatment, a number of scholars have used C3H/HeN mice to establish the model successfully. animal models have been successfully established.Estradiol pretreatment is essential for the animal model of Ureaplasma urealyticum reproductive tract infection, , and BALB / c mice is the preferred experimental animals, while Ureaplasma urealyticum respiratory tract infection model does not need estrogen pretreatment, a number of scholars have used C3H/HeN mice to establish the model successfully.
Pseudomonas aeruginosa and Candida albicans can coexist in human body. There is a complex interaction between the two opportunistic pathogens which was defined as cross-kingdom interaction: Pseudomonas aeruginosa inhibits the morphological change of Candida albicans, the formation of bacterial biofilm and kill the hypha, and Candida albicans inhibits the formation of pyocyanine of Pseudomonas aeruginosa and the swarming motility. Cross-kingdom interaction may exist three mechanisms: quorum sensing, biofilm and toxicity. By secretion of signaling molecule N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL), Pseudomonas aeruginosa inhibits conversion of Candida albicans from yeast to hypha. By secretion of signaling molecule farnesol, Candida albicans inhibits the formation of pyocyanie and swarming motility. It suggests that the cross-kingdom interaction is partly mediated by signal molecules. Due to the presence of cross-kingdom interaction, the pathogenicity of Pseudomonas aeruginosa and Candida albicans is impacted, helpful in choosing the better treatment.
Microbial culture, ELISA, nucleic acid testing are the main methods for clinic microbial testing today. An effective method for microbial enrichment not only will be helpful on optimizing the sensitivity of the follow-up testing, but also will determine the availability of some testing methods when the amount of microorganisms are extremely low in the sample. The research progress on microbial enrichment methods and its applications are reviewed and discussed in this report.
Mycobacterium tuberculosis is an intracellular bacterial infection, macrophages are the parasitic place. Mycobacterium tuberculosis phagocytosis by preventing fusion of lysosomes to reduce macrophage apoptosis, reduced macrophage response sensitivity to stimulate a variety of ways to evade immune surveillance of macrophages and the attacks and in macrophages memory alive and breeding. The macrophage is the main effect of antibacterial immune cells, Mycobacterium tuberculosis has a direct anti-secreted cytokines to immune modulation, presenting the role of bacteria and other antigens. Further study of Mycobacterium tuberculosis on macrophage immune escape mechanisms and the role of macrophages in anti-TB immunity for the study of host immune mechanisms and design of new anti-TB tuberculosis vaccine is important.
Chaperonin GroEL1 in Mycobacterium tuberculosis is a product of gene duplication. As a member of heat shock proteins (HSPs), it not only promotes refolding of model substrates in vitro and in vivo, but also acts as an efficient antigen and performs function in antigen presentation. Besides, it has unique structure features, which possibly provide Mycobacterium tuberculosis with a variety series of biological functions such as regulating the cytokine-dependent granulomatous response in Mycobacterium tuberculosis infection as a protein-chaperonin, and associates with nucleoids to protect DNA as DNA-chaperonin. However, GroEL1 plays different roles in other species of Mycobacteria such as Mycobacterium smegmatis. The reasons and mechanisms of these functions need futher studies to be addressed, providing more basis for the research of the evolutionary mechanism of Mycobacterium tuberculosis.
