Molecular typing of Leptospira interrogans strains isolated from Rattus tanezumi in Guizhou Province, Southwest of China.

Objective: To identify and type three leptospires isolated from Rattus tanezumi in Guizhou Province by using three molecular techniques (PFGE, MLVA, and MLST), reveal the molecular characteristic of causative agents of local leptospirosis and evaluate these three molecular methods based on their detection resolution and efficiency.

Methods: Three Leptospira strains were isolated from the kidney of Rattus tanezumi and cultured with EMJH medium. PFGE, MLVA, and MLST assays were applied to type the three strains isolated from Rattus tanezumi in Guizhou Province.

[Establishment and application of TaqMan Real-time PCR for the detection of pathogenic Leptospira species].

Objective: To develop and evaluate a TaqMan Real-time PCR method for the detection of pathogenic Leptospira species.

Methods: rrs gene of part fragment on 16S rRNA was used to design primers and TaqMan probe. The target gene was cloned into vector pMD19-T in order to make the standard curve and be used for quality control.

Comparative proteogenomic analysis of the Leptospira interrogans virulence-attenuated strain IPAV against the pathogenic strain 56601.

The virulence-attenuated Leptospira interrogans serovar Lai strain IPAV was derived by prolonged laboratory passage from a highly virulent ancestral strain isolated in China. We studied the genetic variations of IPAV that render it avirulent via comparative analysis against the pathogenic L. interrogans serovar Lai strain 56601.

[Molecular typing on Leptospira interrogans isolates from Jiangxi province, by pulsed-field gel electrophoresis].

Objective: To perform a molecular epidemiological investigation on the types of Leptospira interrogans isolates from leptospirosis patients and animal hosts in Jiangxi province, using a pulsed-field gel electrophoresis (PFGE).

Methods: The extracted chromosomal DNA from leptospiral isolates were digested with restriction endonuclease Not I and the DNA segments were separated by using PFGE. By BiOnurerics V4.

Development of O-antigen gene cluster-specific PCRs for rapid typing six epidemic serogroups of Leptospira in China.

Background: Leptospira is the causative agent of leptospirosis. The O-antigen is the distal part of the lipopolysaccharide, which is a key component of outer membrane of Gram-negative bacteria and confers serological specificity. The epidemiology and clinical characteristics of leptospirosis are relative to the serology based taxonomic unit.

[Establishment of standardized method for pulsed-field gel electrophoresis on Leptospira interrogans and analysis on their patterns].

Objective: To establish a standardized operation procedure for pulsed-field gel electrophoresis (PFGE) on Leptospira interrogans as well as a figure digital database to develop the Chinese representative reference strains.

Methods: Under the characteristics of strains and referring to the other SOPs of PFGE on pathogens provided by CDC and PulseNet Asia Pacific, genomic chromosome DNA purification, restriction endonuclease digestion and the parameters for running PFGE were optimized.

Results: Not I digestion patterns of leptospiral genome for the Chinese representative strains were established and partial isolates of serogroup icterohaemorrhagiae from the leptospirosis surveillance in Sichuan and Anhui provinces were analyzed by PFGE.

Expression and comparative analysis of genes encoding outer membrane proteins LipL21, LipL32 and OmpL1 in epidemic leptospires.

Leptospiral outer membrane proteins (OMPs) are highly conserved in different species, and play an essential role in the development of new immunoprotection and serodiagnosis strategies. The genes encoding LipL21, LipL32 and OmpL1 were cloned from the complete genome sequence of Leptospira interrogans serovar lai strain Lai and expressed in vitro. Sequence comparison analysis revealed that the three genes were highly conserved among distinct epidemic leptospires, including three major epidemic species Leptospira interrogans, Leptospira borgpetersenii and Leptospira weilii, in China.

[Surveillance on severe acute respiratory syndrome associated coronavirus in animals at a live animal market of Guangzhou in 2004].

Objective: To study the prevalence of severe acute respiratory syndrome coronavirus (SARS-CoV) like virus in animals at a live animal market of Guanzhou in 2004 before and after culling of wild animal action taken by the local authority, in order to predict the re-emerging of SARS from animal originals in this region.

Methods: Animals at live animal market were sampled for rectal and throat swabs in triplicate. A single step realtime reverse transcription-polymerase chain reaction (RT-PCR) diagnostic kit was performed for screening SARS-CoV like virus, the manual nested RT- PCR and DNA sequencing were performed for confirmation.

[Distribution of virulence associated genes among strains of Leptospira].

Objective: To analyze factors related to the virulence associated genes of Leptospires.

Methods: Twelve putative virulence associated genes were detected by polymerase chain reaction (PCR) method in 38 reference strains, 81 field strains of Leptospira interrogans isolated from patients or animals, and 12 avirulent strains of Leptospira biflexa.

Results: These putative virulent genes were widely distributed among the strains of Leptospira interrogans, but only few of them were detected in Leptospira biflexa.

Unique physiological and pathogenic features of Leptospira interrogans revealed by whole-genome sequencing.

Leptospirosis is a widely spread disease of global concern. Infection causes flu-like episodes with frequent severe renal and hepatic damage, such as haemorrhage and jaundice. In more severe cases, massive pulmonary haemorrhages, including fatal sudden haemoptysis, can occur.