Search results for "Serotyping"
showing 10 items of 61 documents
Genetic Diversity of O-Antigens in Hafnia alvei and the Development of a Suspension Array for Serotype Detection.
2016
Hafnia alvei is a facultative and rod-shaped gram-negative bacterium that belongs to the Enterobacteriaceae family. Although it has been more than 50 years since the genus was identified, very little is known about variations among Hafnia species. Diversity in O-antigens (O-polysaccharide, OPS) is thought to be a major factor in bacterial adaptation to different hosts and situations and variability in the environment. Antigenic variation is also an important factor in pathogenicity that has been used to define clones within a number of species. The genes that are required to synthesize OPS are always clustered within the bacterial chromosome. A serotyping scheme including 39 O-serotypes has…
Pneumococcal Colonization in the Familial Context and Implications for Anti-Pneumococcal Immunization in Adults: Results from the BINOCOLO Project in…
2017
The spread of Streptococcus pneumoniae within families has been scarcely investigated so far. This feasibility study aimed to estimate the prevalence of pneumococcal carriage in school-aged children and co-habiting relatives and to explore the potential link between the family environment and the sharing of pneumococcal serotypes covered by the vaccine. Oropharyngeal samples of 146 subjects belonging to 36 different family groups were molecularly tested for pneumococcal detection and serotyping. The overall prevalence of pneumococcal carriage was 65.8% (n = 96/146), whereas it was higher among schoolchildren (77.8%, n = 28/36); subjects of seven years of age had the highest odds of being co…
Chronic hepatitis C: the viral load per liver cell before treatment as a new marker to predict long-term response to IFN-α therapy
1998
Abstract Background/Aims: So far, there are no reliable parameters that can predict the long-term sustained response to treatment with interferon-α in patients with chronic hepatitis C. In this study, we have developed a semi-quantitative method to determine the viral load per liver cell and have correlated this factor with the outcome of hepatitis C patients treated with interferon-α. Methods: Hepatitis C virus RNA levels were measured in serum, peripheral blood mononuclear cells and liver cells of randomly chosen hepatitis C patients before treatment with interferon-α ( n =37). The number of cells present in the liver biopsies was determined by a polymerase chain reaction-based quantitati…
Molecular Cloning, Expression, Self-Assembly, Antigenicity, and Seroepidemiology of a Genogroup II Norovirus Isolated in France
2003
ABSTRACT Virus-like particles of Dijon171/96 virus, a genogroup II norovirus, were expressed in a baculovirus system and were used for a seroepidemiological study of 1,078 age-stratified human sera collected in Dijon, France. The results showed a seroprevalence of 74.1%. Furthermore, we showed that murine antibodies generated against recombinant Dijon171/96 virus, and human antibodies recognized discontinuous epitopes on the particles.
Anti-rotavirus Antibodies in Human Milk
2006
To analyze anti-rotavirus antibodies in human milk in order to determine their isotypes and neutralizing activity on rotavirus strains representing different viral serotypes.One hundred seventy-three milk samples (65 colostrum, 55 transitional milk and 53 mature milk) obtained from 65 mothers were analyzed along with 49 serum samples collected just before delivery. Total immunoglobulin A (IgA) and rotavirus-specific IgA and immunoglobulins G (IgG) antibodies were determined in milk and serum by enzyme-linked immunosorbent assay. Neutralizing activity was evaluated by an immunoperoxidase focus reduction assay. Milk IgA was purified by binding to the lectin jacalin, elution and ultrafiltratio…
Pneumococcus infections: Is the burden still as heavy?
2012
EA MERS CT3 Enjeu 3; International audience; The death rate of invasive pneumococcal infections decreased by 100 fold in one century. This tremendous improvement was due mainly to antibiotic use and multiple attempts at antipneumococcal vaccinations; thus, this was true only for developed countries. However, in France, the incidence has increased, over the last 10 years, in all age classes except for children vaccinated by the heptavalent pneumococcal conjugate vaccine. The incidence of these infections remains high, when associated to some risk factors such as HIV infection, malignant blood diseases, solid cancers, bronchial diseases, or alcohol abuse. The pneumococcal vaccine should be pr…
Pathogenic Aeromonas hydrophila Serogroup O:14 and O:81 Strains with an S Layer
2004
ABSTRACT Five autoagglutinating Aeromonas hydrophila isolates recovered from eels and humans were assigned to serogroups O:14 and O:81 of the Sakazaki and Shimada (National Institutes of Health) scheme. They had the following properties in common: positive precipitation after boiling, moderate surface hydrophobicity (salt-aggregation-test value around 1.2), pathogenicity for fish and mice (50% lethal dose, 10 4.61 to 10 7.11 ), lipopolysaccharides that contained O-polysaccharide chains of homogeneous chain length, and an external S layer peripheral to the cell wall observed by electron microscopy. A strong cross-reactivity was detected by immunoblotting between the homogeneous O-polysacchar…
Identification of a clone of Escherichia coli O103:H2 as a potential agent of hemolytic-uremic syndrome in France
1993
In a French multicenter study, six verocytotoxin-producing Escherichia coli strains were isolated from the stools of 6 of 69 children suffering from hemolytic-uremic syndrome. All strains belonged to serotype O103:H2, a serotype commonly associated with diarrhea in weaned rabbits in France. To determine whether the strains from humans and rabbits were genetically related, they were compared by analyzing their esterase electropherotypes and the restriction fragment length polymorphisms of the ribosomal DNA regions. A common clonal origin of these pathogenic strains was suggested by their identical esterase electropherotypes and their identical ribotypes, in addition to their identical seroty…
DNA Amplification Fingerprinting for Subtyping Neisseria gonorrhoeae Strains
1995
Background and Objectives DNA amplification fingerprinting is used in most epidemiologic studies as a substitute for conventional typing methods. DNA amplification fingerprinting and conventional typing methods were compared in this epidemiologic study of Neisseria gonorrhoeae. Goal of This Study To differentiate 70 Neisseria gonorrhoeae isolates from untreated patients with urogenital gonococcal infection. Study Design Gonococcal strains were characterized by auxo-typing, serotyping, plasmid profile, antibiotic sensitivity, and DNA amplification fingerprinting. The method of unweighted pair-group average linkage was used for cluster analysis. Discriminatory power was calculated applying Si…
High prevalence of integron-mediated resistance in clinical isolates of Salmonella enterica
2010
Salmonella enterica has become progressively resistant to antimicrobial agents worldwide as a result of genes carried on different classes of integrons. The aim of the current study was to investigate the molecular diversity of these integrons and their association with antimicrobial resistance in clinical S. enterica isolates from Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Integrons were detected in 65 (47.1%) strains, with classes 1 and 2 being observed in 54 (39%) and 11 (8%) strains, respectively. Integron-positive isolates belonge…