Comparative genome characterization of Leptospira interrogans from mild and severe leptospirosis patients

Leptospirosis is a zoonotic disease caused by spirochetes from the genus Leptospira. In Thailand, Leptospira interrogans is a major cause of leptospirosis. Leptospirosis patients present with a wide range of clinical manifestations from asymptomatic, mild infections to severe illness involving organ failure. For better understanding the difference between Leptospira isolates causing mild and severe leptospirosis, illumina sequencing was used to sequence genomic DNA in both serotypes. DNA of Leptospira isolated from two patients, one with mild and another with severe symptoms, were included in this study. The paired-end reads were removed adapters and trimmed with Q30 score using Trimmomatic. Trimmed reads were constructed to contigs and scaffolds using SPAdes. Cross-contamination of scaffolds was evaluated by ContEst16s. Prokka tool for bacterial annotation was used to annotate sequences from both Leptospira isolates. Predicted amino acid sequences from Prokka were searched in EggNOG and David gene ontology database to characterize gene ontology. In addition, Leptospira from mild and severe patients, that passed the criteria e-value < 10e-5 from blastP against virulence factor database, were used to analyze with Venn diagram. From this study, we found 13 and 12 genes that were unique in the isolates from mild and severe patients, respectively. The 12 genes in the severe isolate might be virulence factor genes that affect disease severity. However, these genes should be validated in further study.

Interpretation of microscopic agglutination test for leptospirosis diagnosis and seroprevalence

Determination of antibody titer by microscopic agglutination test (MAT) has been used as a tool for leptospirosis diagnosis. Four fold or greater rise in antibody titers between acute and convalescent sera suggests recent Leptospira infection. In addition, results obtained by MAT have been used to predict infecting serovars. However, cross reactivity among various Leptospira serovars have been reported when patient sera were tested with a battery of Leptospira serovars. This study demonstrates cross- reactivity among several Leptospira serovars when MAT was performed on leptospirosis sera. The data support a role of MAT as a tool for diagnosis. However, for information on infecting serovars, Leptospira isolation and molecular identification should be performed.

Interpretation of microscopic agglutination test for leptospirosis diagnosis and seroprevalence

Determination of antibody titer by microscopic agglutination test (MAT) has been used as a tool for leptospirosis diagnosis. Four fold or greater rise in antibody titers between acute and convalescent sera suggests recent Leptospira infection. In addition, results obtained by MAT have been used to predict infecting serovars. However, cross reactivity among various Leptospira serovars have been reported when patient sera were tested with a battery of Leptospira serovars. This study demonstrates cross- reactivity among several Leptospira serovars when MAT was performed on leptospirosis sera. The data support a role of MAT as a tool for diagnosis. However, for information on infecting serovars, Leptospira isolation and molecular identification should be performed.

Cytokine levels in patients with chikungunya virus infection

OBJECTIVE@#To investigate cytokine profile in patients with chikungunya virus (CHIKV) infection.@*METHODS@#Twenty eight pairs of serum samples collected from CHIKV infected patients during the outbreak of chikungunya fever in South Thailand in 2008 were obtained. A multiple cytokine assay for detection of 17 cytokines was performed.@*RESULTS@#In the acute stage of CHIKV infection, the patients had significantly higher levels of interleukin-6, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein 1 and tumor necrosis factor alpha than the control (P<0.001, P=0.023, P=0.015, P<0.001 and P=0.024, respectively). When the disease developed to the recovery stage, the patients had significantly lower levels of interleukin-6, granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein 1 and macrophage inflammatory protein beta than in the acute stage (P<0.001).@*CONCLUSIONS@#This study provides additional information that these cytokines could play roles in pathogenesis of CHIKV infection and could be used as disease biomarkers or drug targets.

LipL32 mRNA expression in kidneys, livers and lungs of hamsters infected with pathogenic Leptospira

Background: LipL32 is an outer membrane protein of pathogenic Leptospira. Humans and animals infected with Leptospira elicite strong immune responses to this protein. LipL32 induced cytokine expression in mouse proximal tubule cells which suggests its involvement in kidney immunopathogenesis. In addition to kidneys, livers and lungs are others organs frequently affected in leptospirosis. Objective: To demonstrate LipL32 expression in kidney, liver and lung tissues of hamsters infected with pathogenic Leptospira. Methods: RNA was extracted from kidney, liver and lung tissues of hamsters infected with pathogenic Leptospira. LipL32 expression in tissues was investigated using reverse transcription and nested PCR. Results: LipL32 mRNA expression was detected in kidney, liver and lung tissues of hamsters infected with pathogenic Leptospira. No PCR product was detected when tissues from non-infected hamsters were investigated. Conclusion: The data demonstrate that LipL32 is expressed in kidney, liver and lung tissues of animals infected with Leptospira. Further study is needed to demonstrate whether its expression is involved in pathogenesis in those organs.