• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.241-244
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• 2008

This study examined the prevalence of Brucella spp. and Leptospira interrogans in 360 clinically healthy dogs using multiplex nested PCR. Four dogs (1.1%, 2 females and 2 males) tested positive to Brucella spp. by multiplex nested PCR. Fifty nine (16.4%, 31 females and 28 males) of 360 dogs tested positive L. interrogans. In 1 and 2 of the samples that tested positive to Brucella spp. and L. interrogans, the partial sequences of the virB1 and 16S rRNA genes were identified by direct sequence analysis, respectively. In conclusion, prevalence of Brucella spp. and L. interrogans by multiplex nested PCR revealed low and high, respectively. Multiplex nested PCR is can be useful for early detection of Brucella spp. and L. interrogans in the canine blood from asymptomatic dogs.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.591-594
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• 1999

Leptospirosis has been known as endemic disease in Korea since 1984. Wild rodent, mostly Apodemus agrarius, has been known as an important source of leptospiral infection especially in rainy circumstances in harvest reason of rural area. The infection rates of Leptospira interrogans in field rodents, Apodemus agrarius, was investigated by culture and PCR detection of leptospiral DNA, and compared with previous data. Furthermore, the serogroup and serovar were investigated. Two hundred twenty two Apodemus agrarius were captured during October to December 1996. Spirohaetes were isolated from 22 (9.9%) and leptospiral DNA was detected in an additional six rodents (12.6%). Subsequent cross-agglutinin absorption test, monoclonal antibody reactivity classified 21 cultures among 22 isolates as Leptospira interrogans serogroup Icterohemorrhagiae serovar lai. The above data did not differ from previous survey in 1984 to 1987. There was no significant change of Leptospira interrogans infection in field rodents in Korea.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.195-205
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• 1992

The soluble antigen profiles and antigenic specificities of Leptospira interrogans serovars icterhaemorrhagiae, canicola, pomona and hardjo were examined by SDS-polyacrylamide gel electrophoresis, crossed immunoeletrophoresis and immunoblotting. The profiles of protein, glycoprotein and fraction containing N-acetylglucosamine of 4 serovars were compared. The protein profiles of 4 serovars were very similar except the range of 14,400 to 30,000 daltons. Molecular weight of glycoprotein of L, pomona was lower than other serovars. L canicola showed extra N-acetylglucosamine bands having molecular weight of 82,000 and 90,000 daltons. In crossed immunoelectrophoresis, a close antigenic relationship was found between L icterohaemorrhagiae and L canicola. In immunoblottings conducted with soluble antigens and rabbit antisera of 4 serovars, Leptospira interrogans serovars possessed cross-reactive antigens and serovar-specific antigens. The molecular weights of serovar-specific antigens were 45,000, 82,000 and 90,000, 31,000 and 24,000 daltons in L icterohaemorrhagiae, L canicola, L pomona, and L hardjo, respectively.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.331-336
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• 1986

A microbiological study for the isolation and characterization of Leptospira interrogans was performed in an attempt to define the characteristics of Leptospirosis in Korea. The results are summerised as follows. Thirty-five cultures were isolated from 11 patients with leptospirosis and 24 wild rodents captured in Paju area. The isolation rate of Leptospira from wild rodents reached 23.1%. All 35 cultures were identified as Leptospira interrogans by their characteristic morphology and motility in dark field microscopy, pathogenecity in Guinea pig and sensitivity to 8-Azaguanine. Cultures formed diffuse subsurface colonies with hazy margin and were catalase, peroxidase and oxdase positive. The fifty percent lethal dose of isolate HM 4 in Guinea pig was $8.9{\times}10^4$ org. Mouse passage method was sucecssfully applied in maintenance of fresh isolates without any loss of their original virulency.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.779-784
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• 2013

Leptospirosis is a worldwide zoonosis of global concern caused by Leptospira interrogans. The availability of ligand libraries has facilitated the search for novel drug targets using chemogenomics approaches, compared with the traditional method of drug discovery, which is time consuming and yields few leads with little intracellular information for guiding target selection. Recent subtractive genomics studies have revealed the putative drug targets in peptidoglycan biosynthesis pathways in Leptospira interrogans. Aligand library for the murD ligase enzyme in the peptidoglycan pathway has also been identified. Our approach in this research involves screening of the pre-existing ligand library of murD with related protein family members in the putative drug target assembly in the peptidoglycan biosynthesis pathway. A chemogenomics approach has been implemented here, which involves screening of known ligands of a protein family having analogous domain architecture for identification of leads for existing druggable protein family members. By means of this approach, one murC and one murF inhibitor were identified, providing a platform for developing an anti-leptospirosis drug targeting the peptidoglycan biosynthesis pathway. Given that the peptidoglycan biosynthesis pathway is exclusive to bacteria, the in silico identified mur ligase inhibitors are expected to be broad-spectrum Gram-negative inhibitors if synthesized and tested in in vitro and in vivo assays.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.209-218
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• 1987

Leptospira interrogans, the causative organism of leptospirosis, is characterized by a fine helical morphology, and the helix is almost always right-handed. However, one of the striking features of recent isolates of L. interrogans in Korea was the heterogeneity in their morphology. Even under optimal culture conditions($30^{\circ}C$, EMJH medium), rods, spiral forms with right or left-handed helices, and even spherical forms of L. interrogans were present. Although the literature notes the presence of left-handed helices, long rods, and spherical forms in cultures of L. interrogans isolates, little is known about the cause of this morphologic heterogeneity. In an attempt to answer this question, this study was initiated to examine the effects of culture conditions, especially temperature and medium, on the morphology of L. interrogans. Four temperatures($5^{\circ}C$, $15^{\circ}C$, $30^{\circ}C$, and $37^{\circ}C$) and two types of media(Fletcher and EMJH) were used; one strain from Korean isolates and L. interrogans serovar canicola obtained from the Pasteur Institute(Paris, France) were employed throughout the study. The findings are as follows: 1. The L. interrogans isolated in Korea(UM-19) had a larger cell diameter($0.25{\sim}0.30\;{\mu}m$: $0.10{\sim}0.15\;{\mu}m$), and helix diameter($0.10{\sim}0.60\;{\mu}m$: $0.10{\sim}0.15\;{\mu}m$) than that obtained from the Pasteur Institute, but they varied in their distances between the helices($0.31{\sim}1.00\;{\mu}m$: $0.50{\sim}0.70\;{\mu}m$). 2, When UM-19 was grown at $37^{\circ}C$ after months or longer preincubation at $5^{\circ}C$ or $15^{\circ}C$, the majority of the organisms were spiral forms; however, they became rods when subcultured at $30^{\circ}C$ or $37^{\circ}C$. No significant morphological differences were found between Fletcher and EMJH media. 3. When L. interrogans serovar canicola was subcultured more than ten times at $37^{\circ}C$, some of the organism lost their motility as well as the hooks at either one or both ends, but only in Fletcher medium. The number of variants increased with the frequency of subculturing. These findings suggested that L. interrogans strain (UM-19) is different, in their morphology, from that of the Pasteur Institute, and its various morphologies may represent stages of the life cycle and vary with incubation temperature.

• Genomics & Informatics
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• v.19 no.3
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• pp.31.1-31.9
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• 2021

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.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.223-229
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• 1985

We have previously isolated seven strains of spiral form bacteria, which have shown several similar characteristics to Leptospira from patient with epidemic pulmonary hemorrhagic fever and matural paddy water. Further studies have performed to characterize them. All of the isolated bacteria were aerobic, gram negative and spiral form and their growth were completely inhibited at temperature below $13^{\circ}C\;and\;50^{\circ}C$. In sensitivity test to drugs, the bacteria were resistant to the bile salts, 5-Fu and Amphotericine B, but sensitive to the 8-Azaguanine. The isolated bacteria as well as 5 serotypes of Leptospira interrogans reacted the patient sera and it was also shown that antisera from rabbit immunized with the isolated bacteria reacted with 5 serotypes of Leptospira interrogans. These results suggest that the isolated bacteria may belong to the genus Leptospira.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.337-343
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• 1986

To clarify the existing serological varieties of Leptospira interrogans in Korea, 15 isolates of 1985 were serologically studied by cross agglutinin adsorption test. Fourteen cultures except HS 7 belonged to serogroup Icterohemorrhagiae. Isolate HM 3 and HV 8 were considered to belong to serotype mwogolo by their low residual homologous antibody(0.08 to 6.25%) after cross adsorption with serotype mwogolo referene culture and antiserum. Both residual homologous antibody of isolate HS 7 and serotype canicola reference culture remained 1.56%, accordingly HS 7 proved to belong to serotype canicola. The agglutinogens of isolate HY2, AP3, AP4, AP7 and AP9 are considered to closely related to serotype mwogolo, and HM4 and HS6 to serotype birkini, which remained to be further studied. The remaining 5 strains(HY1, HS5, HY10, 310-9, 310-19) could not be attached to any known serotype of Icterohemorrhagiae serogroup by cross adsorption test.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.219-224
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• 1987

A strain of Leptospira interrogans(UM-19) was isolated in 1984 from a patient with epidemic pulmonary hemorrhagic fever. The bacteria has been characterized morphologically by a polymorphism showing spiral forms, short and long rods in culture. In order to study the biological relatedness among these forms of the bacteria, the short rods were separated from others by means of continuous sucrose density gradient centrifugation, and cultured at various temperatures such as $10^{\circ}C$, $15^{\circ}C$, $30^{\circ}C$ and $37^{\circ}C$. It was revealed that cultivation or subcultivation of the short rods has resulted in morphological changes observed by darkfield examination, silver stain, and scanning electron microscope showing spiral forms as well as short and long rods.