Salmonella Shigella (SS) Agar is moderately selective and differential medium for the isolation, cultivation and differentiation of Salmonella spp. and some strains of Shigella spp.
What Bacteria grows on SS Agar?
Result Interpretation of SS Agar
| Organisms | Result |
|---|---|
| Escherichia coli | Small, pink to red |
| Enterobacter, Klebsiella | Larger than E.coli, mucoid, pale, opaque cream to pink |
| Salmonella | Colorless, transparent, with a black center if H2S is produced |
| Proteus | Colorless, with black center |
What method is used to identify Shigella?
Detection of Shigella by PCR assay by the PCR method based on the invasion plasmid antigen H(ipaH) gene from food and faecal samples showed the high prevalence of Shigella spp.
What is the sulfur source in Salmonella Shigella Agar?
Beef extract, proteose peptone: provides the nitrogen, vitamins, and amino acids in SS Agar. Ferric citrate: Sodium Thiosulfate is also a sulfur source, and acts with Ferric Citrate as an indicator to detect hydrogen sulfide production.
Can E coli grow on SS Agar?
Coliforms are partially inhibited on SS Agar but may overcome the inhibitory effects after prolonged incubation. When growing, E. coli produces pink to red colonies, Enterobacter aerogenes produces cream to pink colonies, while Citrobacter and Proteus species produce colonies with gray or black centers.
What color is salmonella on SS Agar?
colorless
On SS Agar, colonies of Salmonella or Shigella are smooth and opaque or colorless. Strains of Salmonella which produce H2S will form black-centered colonies. Lactose-fermenters are pink to rose-red in color and may have a precipitate.
Can E. coli grow on SS Agar?
What media is used for Shigella?
Commonly used primary isolation media include MacConkey, Hektoen Enteric Agar, and Salmonella-Shigella (SS) Agar. These media contain bile salts to inhibit the growth of other Gram-negative bacteria and pH indicators to differentiate lactose fermenters (Coliforms) from non-lactose fermenters such as shigellae.
What is Shigella microbiology?
Shigellae are Gram-negative, nonmotile, facultatively anaerobic, non-spore-forming rods. Shigella are differentiated from the closely related Escherichia coli on the basis of pathogenicity, physiology (failure to ferment lactose or decarboxylate lysine) and serology.
Is Shigella flexneri oxidase test?
Oxidase Test (optional) (TP 26 – Oxidase Test) Shigella species are oxidase negative. All Shigella species ferment mannitol except Shigella dysenteriae and some serotypes of Shigella flexneri.
What is the colony of Salmonella in SS Agar?
On SS Agar, colonies of Salmonella or Shigella are smooth and opaque or colorless. Strains of Salmonella which produce H2S will form black-centered colonies. Lactose-fermenters are pink to rose-red in color and may have a precipitate.
What is Salmonella and Shigella?
Salmonella and Shigella, Culture – Salmonella and shigella represent two of the most common bacterial causes of diarrhea. If other common causes of diarrhea are suspected, they must be ordered individually. For many patients, the cause of gastrointestinal infection is not identified.
What is SSSS agar used for in microbiology?
SS agar is used as a selective and differential medium for the isolation of Salmonella and some Shigella species from clinical as well as non-clinical specimens. This medium is not recommended for the primary isolation of Shigella because of inhibitory to most strains.
What is the typical morphology of Salmonella-Shigella colonies on SS agar?
Salmonella, Shigella, and other non-lactose fermenters appear as transparent or translucent colorless colonies on SS Agar. Colonies of Salmonella spp. may appear with or without black centers (depending on the species isolated). Typical colonial morphology on Salmonella-Shigella Agar after inoculation of Inoculum having 50-100 CFU is as follows:
What is the smell of Salmonella bacteria?
Pathogenic Microbes with characteristics smell (good and bad) On Salmonella-Shigella (SS) agar, Proteus usually smells like “rotten cooked fish”. Sweet grape-like scent Pseudomonas aeruginosa produces a sweet grape-like scent, so wound dressings and agar plates are often sniffed for organism identification.
What is microbial testing?
Microbial testing is the first line of defense against disease-causing bacteria and toxins and supporting public health.
