Performance of Statens Serum Institut Enteric Medium for Detection of Enteric Pathogens in Stool in Routine Laboratory Diagnostics

摘要

Background: We evaluated the performance of Statens Serum Institut enteric medium (SSI) for detection of enteric pathogens in stool in two routine diagnostic laboratories in Nairobi to determine if the detection in stool would be most sensitive and specific in our culture protocol. Methods: Salmonella-Shigella agar (SS), Statens Serum Institut enteric medium (SSI), Deoxycholate Citrate Agar (DCA) and MacConkey media were prepared according to the manufacture's institutions. Diarrheal stool specimens received at the laboratory for routine diagnosis were streaked directly and after enrichment in Selenite F onto the test media and incubated for 24 hours at 37o Centigrade. After incubation, the growth characteristics and chemical reactions was compared with the manual given. Results: SSI medium was a more productive medium in the detection of enteric pathogens in comparison to the other three media (F=2.729, d.f=3 at p≤0.005). It also shows that enrichment of the specimens in Selenite F enhances recovery. Conclusion: SSI enteric medium yields differentiating biochemical reactions that allow direct identification of a range of enteric pathogens thus saving on time and costs. Our revised/modified protocol, where we plated stool samples after enrichment in selenite F broth onto SS and SSI, achieved a high sensitivity of detection and optimal isolation.