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1. The following represents case scenarios about different bacteria isolated fro

ID: 301380 • Letter: 1

Question

1. The following represents case scenarios about different bacteria isolated from different samples. It includes morphological, bio-physiological/ chemical and clinical attributes for each organism. You need to IDENTIFY each organism based off these attributes to the Genus species level. Using Bergey’s Determinitive Bacteriology texts, internet sites and the given flow charts, you should be able to come up with the best Genus species of bacteria for each case.

2. Include a brief but thorough description of the morphology, physiology, habitat, virulence factors etc. for each organism identified. Include references.

Case: During a routine examination of a local athlete during the recent health fair, the doctor attending presented a skin swab to you for identification. Initial culturing techniques revealed a single type of organism which had colonies that appeared yellowish in color.

Further investigation of the strain resulted in the following diagnostic results:

Gram (+) cocci arranged in grape-like clusters

Non-spore former

Produced the enzyme catalase

Beta-Hemolytic

Produces the enzyme coagulase

Acid from mannitol

Yellow-gold colony pigment

Novobiocin sensitive

Explanation / Answer

Non-spore forming bacteria are Actinomycetes, Eryspelothix rhusiopthiae. These are aerobic. Lysozyme is a glycoside hydrolase that catalyzes ththe hydrolysis of 1,4-b4-beta-linkage between N-acetyl muramic acid and N-acetyl-D-glycosamine residues in peptidoglycan, which is the major component of gram positive bacteria cell wall. Beta-hemolytic species causes complete rupture of red blood cells. The name of bacteria is Streptococcus equi. The bacteria which produces enzyme coagulase is Staphylococcus aureus. Acid from mannitol- Staphylococcus and Streptococcus. Staphylococcus aureus appears as graph like clustes viewed through a microscope. It has round, golden-yellow colonies when grow on blood agar plate. Staphylococcus epidermidis? doesnot possess the gelatinase enzyme. So it can not hydrolyze gelatin. It is sensitive to novobiocin.