Gram Positive Extra Notes Flashcards
MRSA Meaning
Methicillin Resistant (penicillin resistance) Staph Areus
Microbrial surface components recognising adhesive matrix molecules Outline
Bacteria antigens binding to host cell receptors enabling attachment to cell (for entry) and eliciting physiological change. Eg fibrin binding protein (allows pathogen to hide in clot) and collagen binding protein
Examples of how pathogens evade phagocytosis
Entry into host cells, biofilms (capsules/slime layers) and production of enzymes/cytotoxins to damage/ destroy immune cells
Coagulase Pathogen and Biological Function
S Areus. Prevents phagocytosis by engulfing bacteria in clot
Protein A Pathogen and Biological Function
Binds IgG preventing phagocytosis
Alpha toxin pathogen and biological function
Lysis of blood cells (particularly monocytes and platelets). Decreased immune response
Staphylokinase pathogen and biological function
S. Areus. Dissolves fibrin clots. Allows further infection and spread
Hyaluronidase pathogen and biological function
S Areus. Breaks down hyaluronic acid in connective tissue allowing infection spread
Toxic Shock Syndrome Toxin 1 Pathogen and biological function
S Areus. Stimulates T-cells to produce excess TNF alpha and interleukins 1 ,2 and 3
Enterotoxin (A,B,C,D,E and G) pathogen and biological function
S Areus. Causes diahorrea and vomiting when ingested
Panton-valentine leukocidin pathogen and biological function
S Areus. Lyses of immune cells by pores in membrane
Biofilm biological function
Prevention of phagocytosis and antibiotic contact. Also enables adherence to host cells
Clositridium species Outline
Gram positive bacilli. Strict anaerobes. Form endospores and powerful exotoxins
Penicillin most susceptible pathogens
Beta-hemolytic streptococci
Penicillin resistant pathogens
S Areus
Cephalosporin susceptible pathogens
penicillin resistant pneumonia, meningitis (better penetration) and used mainly when penicillin allergy
When is vacomycin used
When beta lactam resistant
Macrolide Outline
Protein synthesis inhibitors
Streptococci Outline
Most are faculative anaerobes and others are strict anaerobes
Catalase function
prevents damage done by hydrogen peroxide in air with H2O and O2
Haemolysis Def
Break down of blood. Done in alpha, beta and gamma forms
Lancefield Classification Outlines
Antigen present on cell membrane
Molecular Classification Outline
M Protein gene outline
Classification systems
catalase test, lancefiels classifications, haemolysis and molecular classification
Alpha Haemolysis
Discolouration of haemoglobin to green colour
Beta Haemolysis
Complete breakdown of haemoglobin. White light passes through agar
Gama Haemolysis Outline
No change to haemoglobin
M Proteins Outline
Mediate attachment to cells, prevent phagocytosis
M like proteins outline
Bind IgG and IgM together to prevent antibody attachment
Streptococcal Chemokine protease
Cleave II-8. Prevents neutrophile migration in tissues
Location of colonisation of beta haemolytic streptococci
Lower GIT and lower gastro-urinary tract
VRE Meaning
Vancomycin resistant enterococci. Results of HCAIs. Linezolid is used as a last line treatments
Viridans Classification
Alpha hemolysis and little/no lancefield antigens
Enetrococci Classification
D lancefield antigens, faculative anaerobes and alpha/beta haemolysis
Listeria Moncytogenes Classification
Non-sporing, aerobic and faculative non-aerobic
At risk patients for Enterococci
Recent surgery, maligant disease, trauma, antibiotic use (cephalosporin and aminoglycosides) and ICU hospitalisation
Listeria Monocytogenes Passes
Vertical transmission, animal transmission and uncooked meats
