Microbiology lec4

Medical Microbiology Lecture 3 Dr. Saleh M Y OTH PhD Medical Molecular Biotechnology and Infectious Diseases 02/10/2010 IMS - MSU Systemic Bactreiology

STREPTOCOCCI Systemic Bactreiology

Words must to be known ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Streptococcus pyogenes During the infection, this bacteria produce pus ,[object Object],[object Object],[object Object],[object Object]

Gram Stain of S. pyogenes Streptcoccus pyogenes S. agalactia S. peumoniae

Hemolysis on Blood Agar Plates ,[object Object],[object Object]

S.pyogenes S. pneumonia Beta hemolysis Alpha hemolysis

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Streptococcus in chains (Gram stain)

[object Object],[object Object],[object Object],[object Object]

Groupable streptococci ,[object Object],[object Object],[object Object],[object Object]

Non-groupable ,[object Object],[object Object],[object Object],[object Object],[object Object]

hemolysis reaction - sheep blood agar ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],White colonies

Hemolysis ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

hemolysis reaction + one characteristic presumptive identification

Group A streptococcus ( S. pyogenes ) Group A streptococcal infections affect all ages peak incidence at 5-15 years of age

S. pyogenes – suppurative ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Pyrogenic toxin ,[object Object],[object Object],[object Object]

Pyrogenic toxin … ,[object Object],[object Object]

Scarlet fever - rash - erythrogenic toxin

non-suppurative ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Rheumatic fever is an inflammatory disease that occurs following a Group A streptococcal infection, (such as strep throat or scarlet fever). Believed to be caused by antibody cross-reactivity that can involve the heart, joints, skin, and brain, the illness typically develops two to three weeks after a streptococcal infection. Acute rheumatic fever commonly appears in children between the ages of 5 and 15, with only 20% of first-time attacks occurring in adults. The illness is so named because of its similarity in presentation to rheumatism.

Rheumatic fever -etiology ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Rheumatic fever ,[object Object],[object Object],[object Object]

Acute glomerulonephritis immune complex disease of kidney

Major pathogenesis factors ,[object Object],[object Object],[object Object],[object Object],[object Object]

S. pyogenes fibronectin lipoteichoic acid/F-protein epithelial cells

M protein M protein fibrinogen peptidoglycan IgG Complement IMMUNE NON-IMMUNE r r r r r r

M protein ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Capsules ,[object Object],[object Object]

Isolation and identification ,[object Object],[object Object],[object Object],[object Object],Bacitracin is a mixture of related cyclic polypeptides produced by organisms of the licheniformis group of Bacillus subtilis var Tracy, isolation of which was first reported in 1945. As a toxic and difficult-to-use antibiotic , bacitracin does not work well orally. However, it is very effective topically, and is a common ingredient of eye and skin antibiotic preparations. Its action is on gram-positive cell walls. It can cause contact dermititis due to allergic sensitivity to it.

Β - hemolysis ,[object Object],[object Object],[object Object],[object Object]

Modern Rapid “Strep” Test Throat swab extract (+/- streptococcal antigen) Antibody Liposome + - Streptococcal antigen

Post-infectious diagnosis (serology) ,[object Object],[object Object]

Traditional serotyping of proteins: - M - T - R Typing Modern: - Sequencing of M protein gene

Group B streptococcus ,[object Object],[object Object],[object Object],[object Object]

Group B streptococcus - identification ,[object Object],[object Object],[object Object],[object Object]

Group D streptococcus ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Enterococci ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Enterococci ,[object Object],[object Object],[object Object]

Minute colony streptococci ,[object Object],[object Object],[object Object],[object Object],Large colony Minute colony

Viridans streptococci ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Microbiology lec4

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