Shigella Archives | Microbe Notes

Acetate Utilization Test- Principle, Procedure, Results, Uses

October 4, 2020 by Anupama Sapkota

Acetate Utilization Test- Principle, Procedure and Result Interpretation

What is Acetate Utilization Test? The acetate utilization test is one of the biochemical tests performed for the identification of aerobic organisms by evaluating their ability to utilize acetate present in the growth media. The principle of the acetate utilization test is based on the ability of an organism to utilize acetate as a sole source of carbon. This test …

Shigella dysenteriae- Pathogenicity and Clinical Manifestation

February 4, 2021August 22, 2019 by Sagar Aryal

Shigella dysenteriae is a species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is extremely pathogenic and causes severe dysentery. Infection with this organism often leads to ulceration of the intestinal epithelium. It is known to produce an exotoxin (Shiga toxin) which disrupts protein synthesis and produces endothelial damage. Figure: Shigella spread via fecal-oral and person-to-person transmission. Image Source: https://doi.org/10.1016/j.micres.2015.08.006 Pathogenicity …

Enteroinvasive E. coli (EIEC)

February 4, 2021May 14, 2019 by Sagar Aryal

Enteroinvasive E. coli (EIEC) strains are rare in both developed and developing countries. EIEC infections are characterized by a period of watery diarrhea that precedes the onset of scanty dysenteric stools containing blood and mucus. Pathogenic strains are primarily associated with a few restricted O serotypes: O124, O143, and O164. EIEC strains are biochemically, genetically, and pathogenetically related closely to Shigella spp. …

Biochemical Test of Shigella flexneri

February 4, 2021February 28, 2018 by Sagar Aryal

Biochemical Test of Shigella flexneri Basic Characteristics Properties (Shigella flexneri) Catalase Positive (+ve) Citrate Negative (-ve) Gas Positive (+ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Negative (-ve) Growth in KCN Negative (-ve) H2S Negative (-ve) Indole Variable Motility Non-Motile MR (Methyl Red) Positive (+ve) Nitrate Reduction Positive (+ve) Oxidase Negative (-ve) Pigment Negative (-ve) Shape Rods Spore Non-Sporing Urease Negative …

Laboratory Diagnosis, Treatment and Prevention of Shigella dysenteriae

February 4, 2021October 18, 2017 by Sagar Aryal

Specimens: stool, mucus flecks, and rectal swabs for culture. Large numbers of fecal leukocytes and some red blood cells often are seen microscopically. Microscopic examination Microscopic examination of stool smears reveals higher number of PMN cells. They are Gram negative small rod shaped, non-motile, non-capsulated. Culture and biochemical analysis The materials are streaked on differential media (eg, MacConkey or EMB …

Habitat and Morphology of Shigella dysenteriae

February 4, 2021October 10, 2017 by Sagar Aryal

Habitat of Shigella dysenteriae They are found worldwide. Humans are only the natural host. They are also found in human intestinal tract. They are mostly found in the area where there is overcrowded. Prevalent in low waste management areas and no safe drinking water supply. Houseflies serves as vectors. They are also found in contaminated food and water. They causes …