Identification Of New Serotype Research Articles

Molecular typing and characterization of a new serotype of human enterovirus (EV-B111) identified in China

Molecular methods, based on sequencing the region encoding the complete VP1 or P1 protein, have enabled the rapid identification of new enterovirus serotypes. In the present study, the complete genome of a newly discovered enterovirus serotype, strain Q0011/XZ/CHN/2000 (hereafter referred to as Q0011), was sequenced and analyzed. The virus, isolated from a stool sample from a patient with acute flaccid paralysis in the Tibet region of China in 2000, was characterized by amplicon sequencing and comparison to a GenBank database of enterovirus nucleotide sequences. The nucleotide sequence encoding the complete VP1 capsid protein is most closely related to the sequences of viruses within the species enterovirus B (EV-B), but is less than 72.1% identical to the homologous sequences of the recognized human enterovirus serotypes, with the greatest homology to EV-B101 and echovirus 32. Moreover, the deduced amino acid sequence of the complete VP1 region is less than 84.7% identical to those of the recognized serotypes, suggesting that the strain is a new serotype of enterovirus within EV-B. The virus was characterized as a new enterovirus type, named EV-B111, by the Picornaviridae Study Group of the International Committee on Taxonomy of Viruses. Low positive rate and titer of neutralizing antibody against EV-B111 were found in the Tibet region of China. Nearly 50% of children ≤5 years had no neutralizing antibody against EV-B111. So the extent of transmission and the exposure of the population to this new EV are very limited. This is the first identification of a new serotype of human enterovirus in China, and strain Q0011 was designated the prototype strain of EV-B111.

Epitope mapping and cross-reactivity analysis of the monoclonal antibodies against hexon protein of human adenovirus type 3

Human adenovirus 3 (HAdV-3) occurs epidemically in China in recent years. It can cause life-threatening infection in young children and immunocompromised patients. Development of reliable diagnostic reagents for adenovirus infection is important in surveillance and control of the infection. In this study, three monoclonal antibodies (MAbs) 5D4, 7B2 and 3D10 were generated against the recombinant HAdV-3 hexon protein. Western-blots analysis showed that all three MAbs recognized the native HAdV-3 hexon protein, but only 5D4 reacted with the native HAdV-3 virus particles by indirect enzyme-linked immunosorbent assay (ELISA). The epitopes recognized by these MAbs were further investigated by epitope analysis with a series of peptides of the hexon protein. The epitope for 3D10 was located to the sequence 339GVLAGQASQLNA 350 and present in all the currently recognized serotypes of human adenovirus. The MAb 7B2 showed broad reactivity with the peptides from group B, group E, and most serotypes of group D, but not with those from group A, C and F adenoviruses. The epitope of 5D4, located in the hypervariable region 3 (HVR3), was only shared by HAdV-3 and HAdV-7. Further ELISA demonstrated that 5D4 only recognized HAdV-3 and HAdV-7 virus particles. The MAbs and the identified epitopes may play roles in clinical serotype-specific diagnosis, viral structure analysis, as well as in the identification of new serotypes of human adenovirus.

Identification and molecular characterization of Salmonella spp. from unpasteurized orange juices and identification of new serotype Salmonella strain S. enterica serovar Tempe

Several Salmonella enterica serotypes were isolated from unpasteurized orange juice samples analysed as a follow-up to an outbreak in 1999 of S. enterica serotype Muenchen in the Pacific Northwest regions of United States. Eleven S. enterica strains were serotyped and identified as S. enterica serotype Muenchen (2), S. enterica serotype Hidalgo (2), S. enterica serotype Alamo (1), S. enterica serotype Gaminera (2), S. enterica serotype Javiana (2) and a new serotyped strain S. enterica serotype Tempe (2). The identity of the new serotype S. enterica serovar Tempe serotype 30:b:1,7:z33 was confirmed by the National Salmonella Reference Laboratory at NCID/CDC, Atlanta. These strains were sensitive to ampicillin, chloramphenicol, kanamycin, tetracycline, streptomycin and sulfisoxazole antibiotics. Isolates were screened for invasion ( invA) and virulence ( spvC) genes using specific primers for these two genes by polymerase chain reaction. All strains were positive for invA gene giving 321-bp fragment, however negative to virulence spvC gene. For pulsed-field gel electrophoresis (PFGE) analysis, Salmonella strain plugs were made and digested with XbaI and subjected to 18-h electrophoresis. The PFGE patterns were different for each S. enterica serotypes suggesting the several origins of contamination in outbreak. S. enterica serotype.

Diagnosis of dengue by using reverse transcriptase-polymerase chain reaction.

A rapid identification of dengue viruses from clinical samples by using a nested reverse transcriptase-polymerase chain reaction (RT-PCR) procedure was carried out for diagnostic and epidemiological purposes. RT-PCR identified DEN-1 and DEN-2 viruses in 41% (41/100) of previously confirmed cases and provided an accurate confirmation of DHF in four fatal cases. RT-PCR was also useful for detecting and typing dengue viruses in suspected cases, allowing a rapid identification of new serotypes in endemic areas.