Improved agar plate culture conditions for diagnosis of Strongyloides stercoralis

• Published in: Acta tropica Vol. 203; p. 105291
• Main Authors: Kaewrat, Wannee, Sengthong, Chatchawan, Yingklang, Manachai, Intuyod, Kitti, Haonon, Ornuma, Onsurathum, Sudarat, Dangtakot, Rungtiwa, Saisud, Phitsamai, Sangka, Arunnee, Anutrakulchai, Sirirat, Pinlaor, Somchai, Cha'on, Ubon, Pinlaor, Porntip
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2020
• Subjects: acetates; agar; disease severity; feces; gastrointestinal system; immunocompromised population; larvae; nutrition; Physicochemical factors, Agar plate culture, Worm development; salinity; sodium chloride; Strongyloides stercoralis; strongyloidiasis; temperature; Thailand; yeast extract; Thailand; Strongyloides stercoralis; Physicochemical factors, Agar plate culture, Worm development
• ISSN: 0001-706X; 1873-6254; 1873-6254
• DOI: 10.1016/j.actatropica.2019.105291

•We optimized agar plate culture (APC) for detection of Strongyloides stercoralis.•A pH of 6.0, 0.5% NaCl and temperature of 29–30 °C were found to be optimum.•Testing in an endemic community confirmed this. Strongyloides stercoralis infection causes gastrointestinal symptoms and can lead to severe disease in immunocompromised hosts. Live larvae are passed in feces, encouraging the common use of diagnosis by cultivation methods including agar plate culture (APC), the gold-standard technique. Nevertheless, APC has limitations, especially since there can be considerable day-to-day fluctuations in numbers of larvae produced. Herein, we collected stool samples from heavily infected subjects with strongyloidiasis in Khon Kaen Province, Thailand, to evaluate modifications (temperature, pH, nutrition source and salinity) to APC conditions to maximize the number of S. stercoralis worms counted. Best results were obtained using a modified APC with the following conditions: pH 6.0, 0.5% of NaCl, addition of yeast extract for nutrition and incubation at 29–30 °C. This modified APC was more sensitive for detection of S. stercoralis than was standard APC or the formalin-ethyl acetate concentration technique. In brief, this finding suggests that a modification of standard APC conditions increases the counts of S. stercoralis.