First Report on Leptospira Species Isolated from Patients in Slovenia.

Leptospirosis is an important worldwide zoonosis, and it has also been reported in Slovenia. The cultivation of Leptospira from human material is difficult. Despite that, we successfully isolated 12 human Leptospira strains isolated from patients between 2002 and 2020 and used various methods for the phenotypic and genotypic characterization of the strains, including matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) using our own MALDI-TOF data library, melting temperature analysis of the amplified lfb1 gene, determination of Leptospira serogroups using rabbit immune sera, NotI-RFLP of the whole Leptospira genome, multilocus sequence typing (MLST) of seven housekeeping genes, and whole-genome sequencing (WGS)-based typing. We confirmed the presence of four pathogenic Leptospira species (L. kirschneri, L. interrogans, L. borgpetersenii, and L. santarosai) and three serogroups: Grippotyphosa, Icterohaemorrhagiae, and Sejroe. MALDI-TOF identified three of seven isolates at the species level and four isolates at the genus level. Serovars of 8 of the 10 strains were determined using NotI-RFLP. MLST showed that the clinical isolates belonged to sequence types ST17, ST110, and ST155. WGS confirmed the analysis of Leptospira strains using conventional methods. In addition, WGS provided better taxonomic resolution for isolate DDA 10944/10.

Evaluation of real-time PCR targeting the lipL32 gene for diagnosis of Leptospira infection.

BACKGROUND: Different diagnostic methods have been used for the laboratory confirmation of leptospirosis. Molecular diagnostic techniques are not only faster and more sensitive than culture analysis, but can also detect a Leptospira infection before the appearance of antibodies. The aim of the present study was to analyze and compare two different PCR approaches applied to blood and urine specimens obtained from patients with clinical manifestations that were suggestive of leptospirosis. Furthermore, the results of these different PCR approaches were compared with the results of culture and serology analyses. RESULTS: A total of 400 samples (234 blood or 58.5% and 166 urine of 41.5%) from 310 Slovenian patients with clinical manifestations suggestive of leptospirosis were tested using conventional PCR assays targeting the rrs gene and RT-PCR targeting the lipL32 gene. Additionally, culture, serology and sequence analysis were performed for the majority of these samples. The PCR and RT-PCR results were concordant in 376 out of 400 of these samples (94.0%). Conventional PCR was positive for 27 out of 400 samples (6.8%) and RT-PCR was positive for 47 out of 400 samples (11.8%). Culture and microscopic agglutination tests supported these diagnoses. CONCLUSIONS: A comparison of the two PCR methods indicated that the RT-PCR targeting of the lipL32 gene was faster, more sensitive and more specific for the determination of Leptospira DNA in these clinical samples.

Evaluation of the immunochromatographic (Leptocheck) test for detection of specific antibodies against leptospires.

BACKGROUND: Leptospirosis is a febrile worldwide zoonosis. Routine diagnosis of leptospiral infection is based on demonstration of specific antibodies with serological tests. Performance of the reference serological test, the microscopic agglutination test (MAT), requires significant expertise. The aim of our study was to find out if leptospiral infection can be proven with simple, rapid, commercially available immunochromatographic Leptocheck test in order to introduce it for the first level diagnosis in emergency cases with less specialized laboratory staff. METHODS: In all, 590 serum samples of patients with clinical manifestations suggestive of leptospirosis were collected and tested with MAT and Leptocheck test. For confirmation of the results some other diagnostic methods such as polymerase chain reaction (PCR) and Leptospira isolation were performed. RESULTS: Results of both serological tests were consistent in 576/590 (97.63%) cases but Leptocheck gave more positive results in comparison to MAT (36 and 12, respectively) at first patient's testing. Following up the patient, MAT became positive in majority of Leptocheck positive patients at first visit. Leptospiral DNA was detected in nine blood and six urine samples belonging to thirteen different patients while only two samples were culture positive. CONCLUSION: In comparison with serological tests, PCR and culture have low sensitivity. According to our findings we conclude that Leptocheck test can prove leptospiral infection and could be used for rapid diagnosis of leptospirosis, later the sample should be confirmed with MAT.