Gayan Saranga Sumathipala

Publications

• Patterns of rhinosporidiosis in Sri Lanka: comparison with international data.

  S N Arseculeratne, S Sumathipala, N B Eriyagama

  The Southeast Asian journal of tropical medicine and public health. 01/2010; 41(1):175-91.

  One hundred forty-three cases of rhinosporidiosis, confirmed by smear or biopsy, treated in two major General Hospitals in Sri Lanka over a 14 year period (1995-2009) were analyzed in regard to their epidemiological, clinical, clinicopathological, immunological and microbiological features. Regional... [more] One hundred forty-three cases of rhinosporidiosis, confirmed by smear or biopsy, treated in two major General Hospitals in Sri Lanka over a 14 year period (1995-2009) were analyzed in regard to their epidemiological, clinical, clinicopathological, immunological and microbiological features. Regional variations in incidence, age and sex distribution, bathing history, and histopathology were seen. Lacustrine waters were the commonest probable source of infection (84%). Rivers were a source of Rhinosporidium seeberi in Sri Lanka (11%) and domestic well water was a probable source in 5%. The epidemiological features, clinical presentations and histopathology were similar to those in other series. The antirhinosporidial antibody (mean) titers were IgM--142.1 and IgG--178.5, compatible with rhinosporidiosis of long duration. Mantoux positivity to PPD was found in 65% of normal Sri Lankans, by only 35% of patients with rhinosporidiosis. No outbreaks have been reported in Sri Lanka or India. No animal cases of rhinosporidiosis have been reported in Sri Lanka, although rhinosporidiosis in animals has been repeatedly documented in India.

• A simple fi ltration device for separating nonadherent microorganisms from mammalian cells in in vitro studies on microbial adherence

  Sarath N. Arseculeratne, Saranga Sumathipala, Navaratne B. Eriyagama

  Mycoscience. 10/2008;

  In adherence studies, the removal of nonadherent microorganisms is essential for the valid enumeration of microorganisms that adhere to host cells. Although fi ltration devices are available commercially for the removal of nonadherent microorganisms, these are expensive and not reusable. In this art... [more] In adherence studies, the removal of nonadherent microorganisms is essential for the valid enumeration of microorganisms that adhere to host cells. Although fi ltration devices are available commercially for the removal of nonadherent microorganisms, these are expensive and not reusable. In this article, we describe a simple, inexpensive, and reusable fi ltration device composed of two chambers of nylon, a nylon membrane of desired pore size, a rubber washer, and supporting stainless steel mesh. The device was effective in in vitro adherence assays for removing nonadherent endospores of Rhinosporidium seeberi from human buccal epithelial cells, providing valid counts of adherent microorganisms.

• The Identification of the Natural Habitat of Rhinosporidium seeberi with R. seeberi-Specific in situ Hybridization Probes

  Kumara Kaluarachchi, Saranga Sumathipala, Navaratne Eriyagama, Dhammika Atapattu, Sarath Arseculeratne

  Journal of Infectious Diseases and Antimicrobial Agents. 04/2008; 25:25-32.

  The disease rhinosporidiosis, caused by Rhinosporidium seeberi, has been described in humans and animals since 1892 in at least 70 countries including Europe, North America, South America, Asia, and Africa. South Asia is a known hyper-endemic region. Two persisting enigmas have been the inability to... [more] The disease rhinosporidiosis, caused by Rhinosporidium seeberi, has been described in humans and animals since 1892 in at least 70 countries including Europe, North America, South America, Asia, and Africa. South Asia is a known hyper-endemic region. Two persisting enigmas have been the inability to culture R. seeberi in vitro and to establish experimental rhinosporidiosis in animals. The natural habitat of R. seeberi remains unknown, although there is evidence for an aquatic habitat. A R. seeberi-specific, fluorescein isothiocyanate (FITC)-labelled probe, and a complement of the R. seeberi-specific probe as a control probe, were used to investigate, by in situ hybridization, the putative ground-water habitat of R. seeberi. Sections of paraffin wax-embedded, purified rhinosporidial endospores, and human nasal, rhinosporidial tissue, served as positive controls. A human nasal, nonrhinosporidial polyp was used as a negative control. Entities were identified, with 15-30 μm diameters, compatible morphologically with endospores and juvenile sporangia of R. seeberi. These entities were positively labelled with the FITC-labelled R. seeberi-specific probe, in four replicated experiments, in paraffin wax-embedded deposits of lake water. No labelling with the same R. seeberi-specific probe was seen on the human, non-rhinosporidial polyp, or on the background (non-rhinosporidial) areas of the rhinosporidial polyp. Spicules of sand particles in this water deposit were identified as possible causes of injury to the ocular and nasal mucosae that could initiate colonization by the aquatic R. seeberi. This, as far as we are aware, is the first specific demonstration of the aquatic habitat of Rhinosporidium seeberi. (J Infect Dis Antimicrob Agents 2008;25:25-32.)

• In vitro Susceptibility of the Endospores of Rhino- sporidium seeberi to Seven Antimicrobial Agents

  Sarath Arseculeratne, Ranjith Kumarasiri, Saranga Sumathipala, Dhammika Atapattu, Navaratne Eriyagama, Pushpa Balasooriya, Ranjan Fernando

  Journal of Infectious Diseases and Antimicrobial Agents. 01/2008; 25:135.

  Rhinosporidium seeberi, the causative agent of human and animal rhinosporidiosis, has not been cultured in vitro, and experimental rhinosporidiosis has not been established. Hence, there have been no available data on its susceptibility to antimicrobial agents. Based on a previous study regarding th... [more] Rhinosporidium seeberi, the causative agent of human and animal rhinosporidiosis, has not been cultured in vitro, and experimental rhinosporidiosis has not been established. Hence, there have been no available data on its susceptibility to antimicrobial agents. Based on a previous study regarding the use of 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide (MTT)-reduction to a formazan as a test of viability of rhinosporidial endospores, MTT-reduction test was used to determine the in vitro susceptibility of the endospores of R. seeberi to seven antimicrobial agents in current clinical use on humans and animals. In this study, the inhibitory concentrations at the 50-percent end-point (IC50) (number of experiments) of amphotericin B, dapsone, ketoconazole, trimethoprim-sulfadiazine, sodium stibogluconate, and berenil, and imizol were 57.1 (8), 29.7 (10), 51 (8), 38.4 (9), 55.7 (7), 12.5 (5), 9 (1) μg/mL, respectively. The drug concentration-dependent effects included deformation, enlargement or fragmentation, and decreased staining with formazan of the intra-endosporial electron dense bodies, without abnormalities of the endospore wall. All agents were non-lytic, endosporostatic, and not endosporicidal. The results with amphotericin B, ketoconazole, and especially dapsone, correlated with the clinical responses of patients with rhinosporidiosis, reported in the literature. No correlation of the IC50 with the clinical source of R. seeberi strain, was observed. This is the first full report on antimicrobial agents active against R. seeberi, in vitro. (J Infect Dis Antimicrob Agents 2008;25:135-43.)