A clinical pilot study for the detection of sphingomyelinase in leptospirosis patient's urine at tertiary care hospital.

Purpose: Leptospirosis is a perplexing mystification for many clinicians. Clinically often underdiagnosed due to lack of a rapid, sensitive, and specific diagnostic test. Currently available diagnostic tests have their own limitations; therefore, monitoring biomarkers that contribute an essential role in pathogenesis is crucial. Herein, a pilot study was conducted to detect the presence of sphingomyelinase in urine of leptospirosis patients. Methods: Blood and urine samples were collected from 140 patients having febrile illness. Samples were analyzed through culturing, dark-field microscopy, detecting anti-leptospiral antibodies by MAT, IgM ELISA, Leptocheck-WB and screening for sphingomyelinase using a sphingomyelinase assay kit. Results: Out of 140 febrile illness patients, 22.14 % were tested leptospirosis, 33.57 % were dengue, 25 % scrub typhus, 18.57 % malaria and 0.71 % co-infection (dengue-leptospirosis). MAT seropositivity of 19.28 % (27/140) was confirmed with the highest agglutinant determined against serovar Icterohaemorrhagiae RGA followed by Autumnalis, Australis, and Pyrogens. IgM ELISA and Leptocheck-WB positivity was 16.42 % and 13.57 % respectively. Whereas culture and dark-field microscopy showed a sensitivity of 4.28 % and 2.1 %, respectively. Out of 31 confirmed cases of leptospirosis, sphingomyelinase was detected in the urine of 25 (80.64 %) patients, MAT positivity was seen in 87.09 % and culture positivity was seen in 12.90 % of cases. Conclusion: Detection of sphingomyelinase in the urine of a leptospirosis patient and its absence in other febrile illnesses like dengue, malaria and scrub typhus establish evidence of secretion of sphingomyelinase in urine during leptospiral infection. Hence, sphingomyelinase could be used as a potential diagnostic biomarker to detect leptospirosis in a non-invasive way.

Leptospiral sphingomyelinase Sph2 as a potential biomarker for diagnosis of leptospirosis.

Leptospirosis is an underestimated infectious tropical disease caused by the spirochetes belonging to the genus Leptospira. Leptospirosis is grossly underdiagnosed due to its myriad symptoms, varying from mild febrile illness to severe haemorrhage. Laboratory tests for leptospirosis is an extremely important and potent way for disease diagnosis, as the clinical manifestations are very similar to other febrile diseases. Currently available diagnostic techniques are time-consuming, require expertise and sophisticated instruments, and cannot identify the disease at an early phase of infection. Early diagnosis of leptospirosis is the need of the hour while considering the severe complications after the infection and the rate of mortality after misdiagnosis. Secretion of Leptospira-specific sphingomyelinases in leptospirosis patient's urine within a few days of the onset of infection is quite common and is a virulence factor present only in pathogenic Leptospira species. Herein, the structural and functional importance of leptospiral sphingomyelinase Sph2 in leptospirosis pathogenesis, as well as the potential of screening urinary Sph2 for diagnosis and the scope for developing a rapid and easily affordable point-of-care test for urinary leptospiral sphingomyelinase Sph2 as an alternative to current diagnostic methods are discussed.

Evaluation of anti-LipL32 carbon nanotube immunofluorescence probe (carbo-lip) and comparison with MAT, IgM ELISA, IgM spot test and culture for early detection of leptospirosis at local hospital.

Leptospirosis is an emerging public health problem affecting people mainly from tropical and subtropical regions. Therefore, there is a need for rapid and sensitive tests for proper and prompt treatment. Recently we have demonstrated Carbo-Lip probe, which was fabricated through immuno recognition method with fluorescent dye functionalized LipL32 monoclonal antibodies, secondary antibody and Leptospira for rapid and accurate diagnosis. In an effort to validate Carbo-Lip, we collected clinical samples from a cohort of 104, consisting of 26 positive, 40 negative and 38 unconfirmed cases of Leptospirosis. Subsequently, the test was also compared and validated with the gold standard method microscopic agglutination test (MAT), IgM ELISA, IgM spot test, and culture. Carbo-Lip exhibited a sensitivity of 75% with specificity of 92.3% for Leptospirosis in comparison with MAT. The fabricated Carbo-Lip sensor could be used as a potential diagnostic tool for early detection of Leptospirosis in patients from endemic areas.