Medicine
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/12
This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
Browse
8 results
Search Results
Item 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.Item 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.Item Diagnosing Cutaneous leishmaniasis using Fluorescence in Situ Hybridization: the Sri Lankan Perspective(Taylor & Francis, 2019) Kaluarachchi, T.D.J.; Weerasekera, M. M.; McBain, A. J.; Ranasinghe, S.; Wickremasinghe, R.; Yasawardene, S.; Jayanetti, N.; Wickremasinghe, R.Cutaneous leishmaniasis (CL) caused by Leishmania donovani MON-37 is becoming a major public health problem in Sri Lanka, with 100 new cases per month being reported in endemic regions. Diagnosis of CL is challenging for several reasons. Due to relative specificity and rapidity we propose Fluorescence in Situ Hybridization as a diagnostic tool for CL. The objective was to evaluate the potential of Fluorescence in Situ Hybridization as a diagnostic method for Cutaneous leishmaniasis in Sri Lanka. Literature on current laboratory tests used to diagnose Cutaneous leishmaniasis in Sri Lanka and globally was reviewed. Sri Lankan data were reviewed systematically following the PRISMA guidelines. A narrative of the results is presented. There is currently no gold standard diagnostic method for Cutaneous leishmaniasis. Fluorescence in Situ Hybridization has been previously applied to detect dermal pathologies including those involving infectious agents, and its use to detect the Leishmania parasite in human cutaneous lesions reported in small number of studies, generally with limited numbers of subjects. Advantages of FISH has been specificity, cost and ease-of-use compared to the alternatives. Based on the available literature and our current work, FISH has potential for diagnosing CL and should now be evaluated in larger cohorts in endemic regions. FISH for CL diagnosis could find application in countries such as Sri Lanka, where laboratory facilities may be limited in rural areas where the disease burden is highest.Item Evaluation of rapid extraction and isothermal amplification techniques for the detection of Leishmania donovani DNA from skin lesions of suspected cases at the point of need in Sri Lanka(BioMed Central, 2018) Gunaratna, G.; Manamperi, A.; Bohiken-Fascher, S.; Wickremasinghe, R.; Gunawardena, K.; Yapa, B.; Pathiana, N.; Pathirana, H.; de Silva, N.; Sooriyaarachchi, M.; Deerasinghe, T.; Mondal, D.; Ranasinghe, S.; Abd EI Wahed, A.BACKGROUND: Leishmaniasis is a disease caused by vector-borne protozoans. In Sri Lanka, the cutaneous form of the disease is predominant, which is usually diagnosed using Giemsa-stained slit skin smear examination and by histology. However, the sensitivity of slit skin smears and histology are reportedly low. Moreover, facilities for the highly sensitive polymerase chain reaction (PCR) are available only in a few highly-equipped parasitology laboratories. Therefore, there is a need for low cost, sensitive and specific screening tests for diagnosis of leishmaniasis at the point of need. RESULTS: In this study, a mobile suitcase laboratory applying novel extraction (SpeedXtract) and isothermal amplification and detection (recombinase polymerase amplification assay, RPA) methods were evaluated for the diagnosis of cutaneous leishmaniasis in Sri Lanka. First, the developed assay was applied to three different sample types (punch biopsy, slit skin smears and fine needle aspirates) at a local hospital. The results showed that the 2 mm punch biopsy sample produced the best exponential amplification curve and early fluorescence signal in the RPA assay. Secondly, punch biopsies were collected from 150 suspected cutaneous leishmaniasis cases and screened with SpeedXtract/RPA, RNAlater/PCR and ATL buffer/PCR, in addition to Giemsa-stained slit skin smears. Fifty-seven samples were negative in all detection methods. In total 93 samples were positive with assay sensitivities of 65.5% (SpeedXtract/RPA), 63.4% (RNAlater/PCR) and 92.4% (ATL buffer/PCR). The Giemsa-stained slit skin smear delivered the worst clinical sensitivity (32.2%). CONCLUSIONS: The SpeedXtract/RPA method under field conditions took 35 min, while almost 8 h were needed to finalize the extraction and detection by PCR in the laboratory. The SpeedXtract/RPA method produced similar sensitivity to samples preserved in RNAlater and subjected to PCR amplification, but both were less sensitive than ATL-preserved samples subjected to PCR amplification. There is a need for a standardization of sample collection and nucleic acid extraction methods.Item Efficacy of a new rapid diagnostic test kit to diagnose Sri Lankan cutaneous leishmaniasis caused by Leishmania donovani(Public Library of Science, 2017) de Silva, G.; Somaratne, V.; Senaratne, S.; Vipuladasa, M.; Wickremasinghe, R.; Wickremasinghe, R.; Ranasinghe, S.BACKGROUND: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani. This study assessed the diagnostic value of a new rapid diagnostic immunochromatographic strip (CL-Detect™ IC-RDT), that captures the peroxidoxin antigen of Leishmania amastigotes. METHODOLOGY/PRINCIPAL FINDINGS: We sampled 74 clinically suspected CL lesions, of which 59 (79.7%) were positive by PCR, 43 (58.1%) by Giemsa stained slit skin smear (SSS) and 21 (28.4%) by the new IC-RDT. All samples which were positive either by SSS or IC-RDT or both were positive by PCR. The sensitivities of the IC-RDT and SSS compared to PCR were 36% and 73%, respectively. Fifteen patients from this endemic region were negative by all three tests. Twenty two clinically non-CL skin lesions from a CL non-endemic region were also negative by all three methods. Specificity and PPV of both IC-RDT and SSS compared to PCR were 100%; the NPVs of IC-RDT and SSS were 37% and 58%, respectively. The median parasite grading of the 59 PCR positive samples was 2+ (1-10 parasites/100 HPFs) and IC-RDT positive lesions was 3+ (1-10 parasites /10HPFs). The duration of the lesion was not associated with IC-RDT positivity. CONCLUSIONS/SIGNIFICANCE: The median parasite grade of Sri Lankan CL lesions is low. The low sensitivities of SSS and CL Detect™ IC-RDT may be due to low parasite counts or low expression of peroxidoxin antigen in amastigotes of the Sri Lankan L. donovani strain. Our results indicate that negative SSS has to be combined with PCR for confirmation of CL in Sri Lanka. The current commercially available IC-RDT is not suitable to diagnose CL in Sri Lanka; an IC-RDT with improved sensitivity to detect L. donovani would be a valuable addition in the diagnostic tool kit for Sri Lanka.Item Association between road accidents and low-grade hepatic encephalopathy among Sri Lankan drivers with cirrhosis: a prospective case control study(Biomed Central, 2016) Subasinghe, S.K.C.E.; Nandimuni, Y.; Ranasinghe, S.; Niriella, M.A.; Miththinda, J.K.N.D.; Dassanayake, A.S.; de Silva, A.P.; de Silva, H.J.BACKGROUND: Low-grade hepatic encephalopathy (LGHE) comprises minimal hepatic encephalopathy (MHE) and grade 1 hepatic encephalopathy. LGHE has no or minimal recognizable symptoms but has mild cognitive and psychomotor deficits. Studies in Western countries have demonstrated increased road accidents (RA) among patients with MHE. Our objective was to investigate the association between Sri Lankan LGHE phenotype and RA. STUDY DESIGN AND METHODS: A prospective, case–control study was conducted in the University Medical Unit, North Colombo Teaching Hospital, Ragama Sri Lanka. Patients with cirrhosis of any aetiology, without OHE, who had been driving during previous 1 month were included. A similar number of age matched, healthy control drivers were also enrolled. Both groups were subjected to five pencil-paper based psychometric tests used to detect LGHE in cirrhotics. Self-reported RA during the previous 1 month were recorded: categorized as ‘major’ when resulted in hospitalization of the involved, ‘minor’ when there were injuries, but not serious enough for hospitalization of the involved and ‘other’ when limited to damages to vehicle or environment without injuries. RESULTS: Among 55 drivers with cirrhosis and LGHE [males, median age 53 years (range 30–60)], 7 (12.7 %) reported RA compared to 6 (10.9 %) among 55 controls [males; median age 51 years (range 30–60)]. There were no ‘major’ accidents in either group. 2/55 (3.6 %) cases and 2/55 (3.6 %) controls reported ‘minor’ accidents. CONCLUSION: There was no increased frequency of RA among Sri Lankan drivers with LGHE compared to healthy controls. This is with the limitation of the study based only on self reported RA.Item Association between road accidents and minimal hepatic encephalopathy in a cohort of Sri Lankan cirrhotic drivers(Wiley Blackwell Scientific Publications, 2014) Subasinghe, S.K.C.E.; Nandamuni, Y.; Ranasinghe, S.; Kodisinghe, K.; Niriella, M.A.; de Silva, A.P.; de Silva, H.J.OBJECTIVE: Minimal hepatic encephalopathy (MHE) has no recognizable clinical symptoms of hepatic encephalopathy (HE) but has mild cognitive and psychomotor deficits which can interfere with executive decision making and psychomotor speed. It affects driving ability and previous studies in Western countries have demonstrated an association between MHE and increased road accidents. Our objective was to investigate this association in a cohort of Sri Lankan cirrhotic drivers. METHODS: A prospective, case controlled study ongoing study has been conducted in the Gastroenterology Clinic, University Medical Unit, North Colombo Teaching Hospital, Ragama, from August 2013. Patients with cirrhosis of any aetiology, without overt HE, who had been driving any vehicle during the past one month were subjected to 5 standard pencil-paper based psychometric tests used to detect MHE. Road accidents were recorded for both cirrhotic drivers with MHE and controls. Accidents were categorized as major when they resulted in hospitalization of the involved person/s, and minor when there were no serious injuries. RESULTS: Among 55 cirrhotic drivers with MHE [males, median age 53 years (range 30-60)], 7 (12.7%) reported any type of accident compared to 6 (10.9%) among 55 controls [males; median age 51 years (range 30-60)]. 2/55 (3.6%) cases and 2/55 (3.6%) controls reported minor accidents. There were no major accidents in either group. CONCLUSION: Preliminary results of this ongoing study do not indicate an increased frequency of road accidents in a cohort of Sri Lankan cirrhotic drivers with MHEItem Cross-sectional study to assess risk factorsfor leishmaniasis in an endemic region in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2013) Ranasinghe, S.; Wickremasinghe, R*.; Munasinghe, A.; Hulangamuwa, S.; Sivanantharajah, S.; Seneviratne, K.; Bandara, S.; Athauda, I.; Navaratne, C.; Silva, O.; Wackwella, H.; Matlashewski, G.; Wickremasinghe, R.Sri Lanka reports significantly more cutaneous leishmaniasis (CL) cases than visceral leishmaniasis (VL) cases, both of which are caused by Leishmania donovani MON-37. A cross-sectional study conducted in an area with a high prevalence of CL prevalent included 954 participants of an estimated population of 61,674 to estimate the number of CL cases, ascertain whether there is a pool of asymptomatic VL cases, and identify risk factors for transmission. A total of 31 cases of CL were identified, of whom 21 were previously diagnosed and 10 were new cases. Using rK39 rapid diagnostic test to detect antibodies against Leishmania spp., we found that only one person was seropositive but did not have clinical symptoms of CL or VL, which indicated low transmission of VL in this area. χ(2) test, independent sample t-test, and multivariate analysis of socio demographic and spatial distribution of environmental risk factors showed that living near paddy fields is associated with increased risk for transmission of CL (P ≤ 0.01).