Browsing by Author "Jayathilake, S."

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Diagnosing human cutaneous leishmaniasis using fluorescence in situ hybridization
(Taylor & Francis Publishing, 2021) Kaluarachchi, T.J.; Wickremasinghe, R.; Weerasekera, M.; Yasawardene, S.; McBain, A.J.; Yapa, B.; de Silva, H.; Menike, C.; Jayathilake, S.; Munasinghe, A.; Wickremasinghe, R.; Ranasinghe, S.
ABSTRACT: Cutaneous leishmaniasis (CL) is endemic in Sri Lanka. Giemsa-stained slit-skin-smears (SSS-Giemsa) and histology are routinely used in diagnosis with a sensitivity of 40-70%. PCR currently has limited accessibility. Therefore, we assessed the sensitivity and specificity of a previously described fluorescence in situ hybridization assay, on skin smears and biopsy samples to overcome the limitations encountered with routine diagnostic methods.Samples from a total of 123 suspected CL patients were collected and subjected to SSS-Giemsa, fluorescence in situ hybridization (FISH) on slit skin smears (SSS-FISH), formalin-fixed-paraffin-embedded-tissues stained with Hematoxylin & Eosin staining (FFPE-H&E) and FISH on formalin-fixed-paraffin-embedded-tissues (FFPE-FISH). Negative controls of 61 patient samples were collected from a CL non-endemic area and subjected to the same procedures. The gold standard PCR was used as a comparator. For FISH, two previously described cyanine 3 tagged Leihsmania genus-specific probes were used.Compared to PCR, SSS-Giemsa, SSS-FISH, FFPE-H&E, and FFPE-FISH had sensitivities of 76.5%, 79.1%, 50.4% and 80.9%, respectively. Routine diagnostic tests (SSS-Giemsa and FFPE-H&E) had a specificity of 100%. SSS-FISH and FFPE-FISH had specificities of 96.7% and 93.4%, respectively. FFPE-FISH had a statistically significant higher diagnostic performance than FFPE-H&E (p < 0.001). The relative performance of SSS-Giemsa, SSS-FISH and FFPE-FISH was similar (p > 0.05 for all comparisons).We conclude that FFPE-FISH is a more accurate diagnostic tool than FFPE-H&E. SSS-FISH did not have an additional advantage over SSS-Giemsa in diagnosis. However, SSS-FISH could be recommended as a minimally invasive method in studies assessing wound healing where immunological probes are used. KEYWORDS: Cutaneous leishmaniasis; Sri Lanka; fluorescence in situ hybridization.
Distinct microbiome profiles and biofilms in Leishmania donovani-driven cutaneous leishmaniasis wounds
(Nature Publishing Group, 2021) Kaluarachchi, T.D.J.; Campbell, P.M.; Wickremasinghe, R.; Ranasinghe, S.; Wickremasinghe, R.; Yasawardene, S.; de Silva, H.; Menike, C.; Jayarathne, M.C.K.; Jayathilake, S.; Dilhari, A.; McBain, A.J .; Weerasekera, M.M.
The endemic strain of Leishmania donovani in Sri Lanka causes cutaneous leishmaniasis (CL) rather than more common visceral form. We have visualized biofilms and profiled the microbiome of lesions and unaffected skin in thirty-nine CL patients. Twenty-four lesions (61.5%) were biofilm-positive according to fluorescence in situ hybridization. Biopsies of biofilm-positive lesions were dominated by Pseudomonas, class Bacilli and Enterobacteriaceae and distinguished by significantly lower community evenness. Higher relative abundance of a class Bacilli OTU was detected in wound swabs versus contralateral skin. Wound swabs and biopsies had significantly distinct microbiome profiles and lower diversity compared to unaffected skin. Greater abundances of potentially pathogenic organisms were observed in wet ulcers, lesions with high parasite loads and large wounds. In summary, more than half of L. donovani associated CL wounds harboured biofilms and the wounds exhibited a distinct, less diverse, microbiome than unaffected skin.
Prevalence of NS-1 Status of Clinically Suspected Dengue Patients in a Selected Out-Patient Setting
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Kodikara, K.; Jayathilake, S.; Kumarasinghe, B.; Muhandiramlage, T.; Gunesakera, D.; Fujii, Y.
Dengue infection is one of the rapidly emerging arboviral infections in the world. It is a cause of significant morbidity and mortality especially in developing countries. Although most dengue infections are asymptomatic, dengue fever can be manifested with or without complications. Early diagnosis of dengue is important both clinicians and the patients, where appropriate management of dengue patients reduces both morbidity and mortality. Traditionally dengue infection is clinically suspected with full blood count aided by clinical features although dengue infection cannot be confirmed by either of these methods. Confirmatory tests for detection of the dengue virus are by virus isolation or by nucleic acid detection. which are not suitable for routine diagnosis. NS-1 rapid antigen test has become available for early detection of dengue NS1 antigen, which can be performed at the point of care. Estimate the prevalence of NS1 positivity in dengue suspected patients with acute febrile illness in a selected study setting Blood samples from clinically suspected patients within the first five days of fever were sent for NS1 diagnosis to the molecular laboratory in the department of Biochemistry Faculty of Medicine Ragama. Clinical diagnosis was made by a medical officer. Serum was used for the NS1 diagnosis using Inbios Diagnostic kit (USA). 22.2% of samples were tested positive for NS-1 antigen in a total of 54 samples collected. There were 53.7% males. 9.2% patients were below 10 years of age, 37% patients between 11-20 years of age, 20.3% patients between 21-30 years and 31.4% patients above 31 years of age. 30 % of patients between 11-20 years were NS-1 positive. 36.3 % of patients between 21-30 years of age and 11.7% patients above 31 years of age were also NS-1 positive. NS-1 antigen prevalence was highest among patients between the ages of 11-30 years. Initial clinical assessment of dengue infections is of low specificity as the disease manifests as an undifferentiated febrile illness. Therefore, the inclusion of an antigen test will improve the specificity of diagnosis in a similar out-patient setting which will enable clinicians to make decisions on the further management of the condition.