The genus Salmonella is a member of the family Enterobacteriaceae, It is composed of bacteria related to each other both phenotypically and genotypically. They are gram negative rods with rapid growth under both aerobic and anaerobic conditions . In particular, we were interested in evaluating the number of cells adhering to the slides following the Gram staining procedure. Gram staining is a differential staining technique that differentiates bacteria into two groups: gram-positives and gram-negatives. Gram-stain: Gram-positive cocci and Gram-negative bacilli : Microscopic appearance: Cocci in grape-like clusters (S.aureus) and bacilli(E.coli) Clinical significance of S.aureus: Frequently found as part of the normal skin flora on the skin and nasal passages; It is estimated that 20% of the human population are long-term carriers of S. aureus E. coli is described as a Gram-negative bacterium. Describe the abilities of E. coli, shigella, and salmonella to ferment lactose and glucose . While some of the infections can be easily treated, some of the strains have been shown to resist antibiotic treatment. Then, either MacConkey agar or EMB agar (or both) are inoculated with the stool. K.Pneumoniae is a gram negative (gram stain determines the presence of an external membrane) bacteria that falls in the category of facultative anaerobic, which means it can survive in the presence or absence of oxygen. Salmonella, Shigella, and Yersinia cause a well-characterized spectrum of disease in humans, ranging from asymptomatic carriage to hemorrhagic colitis and fatal typhoidal fever. An assay to identify the common food-borne pathogens Salmonella, Escherichia coli, Shigella, and Listeria monocytogenes was developed in collaboration with Ibis Biosciences (a division of Abbott Molecular) for the Plex-ID biosensor system, a platform that uses electrospray ionization mass spectroscopy (ESI-MS) to detect the base composition of short PCR amplicons. Read more about Salmonella infections. It is widely distributed in nature (Brooker 2008).Escherichia coli (E. coli) is part of the normal intestinal flora. Start studying Bacteria VII: Klebsiella, Salmonella, Shigella, E. coli, Yersinia Enterocolitica. These pathogens are responsible for millions of cases of food-borne illness in the U.S. each year, with substantial costs measured in hospitalizations and lost productivity. Gram Staining Reaction – Salmonella typhi is a Gram -ve (Negative) bacterium. ... How could you differentiate between e coli and staph epidermidis using a simple stain? Gram positive bacteria have cell walls composed mostly of a substance unique to bacteria known as peptidoglycan, or murein. In Gram-negative bacteria, the cell wall is only 1–3 layers thick , and in E. coli 80% or more of the peptidoglycan exists as a monolayer . (CDC) Salmonella Nomenclature. E. coli is Gram negative and will stain red. This is diagnosic of E. coli. If for some reason you wanted to double check your Gram staining, you could try to grow each bacteria on a Phenylethyl alcohol (PEA) agar. MORPHOLOGY OF SALMONELLA TYPHI CULTURE REQUIREMENTS OF SALMONELLA TYPHI (S. TYPHI) ⇒ Special requirements – Salmonella typhi or S. typhi have no complex nutritional requirements and readily grow in an ordinary media like Nutrient Agar medium (NAM).