Micro J210 Streptococci

• -Yes streptococcus pyogenes, post-infection complications
• -Impetigo is highly communicable, most common in daycare centers

• -Gram positive, catalase negative cocci.
• -Grow on blood agar and usually facultative anerobes
• -Many (30+) species that often grow in animals

-A surface carbohydrate used for grouping

-A, B, C, D,....V

-Dr. Rebecca Lancefield (Lancefield grouping of strep)

-Different groups cause different diseases which requires differenet treatment

-Antiboides are non portective but are helpful for typing the agent

• -Alpha (a) incomplete hemolysis (greenish color
• -Beta (B) complete hemolysis
• -Gamma (y) no hemolysis

1 out of 3: cuts odds down 3 times

• -Separate features produce different results. Not 100% reliable, use what we can
• -pattern of hemolysis complements C carb grouping

• -S. pyogenes, group A, hemolysis B (strep throat)
• -S. agalactiae, group B, mostly hemolysis B
• -S. faecalis, group D, a or B hemolysis
• -Viridans group, nongroupable, a or y hemolysis (dental cavities)
• -S. pneumoniae, nongroupable, a hemolysis (Otis media, pnemonia, sinuitis)

-No, not pathogenic

• aka GAS
• -Gram +, catalase -, B cocci, which are bacitracin sensitive (Zone of inhibition)

• -Cell membrane: Variety of functions
• -Peptidoglycan layer of cell envelople: Strength, strucutre
• -C group carboyhydrate: means of grouping
• -Capsule: Hyaluronic acid which is an antiphagocytic
• -M protein: most important virulence factor: attachment helper type 1, gets rid of anti-M protein

Releases Extracellular toxins

• -Capusle: similar to host CT component no AB. Helps resist phagocytosis by PMNs
• -Lipoteichoic acid: Mediates attachment to epithelial cells
• -petidoglycan: is resistant to lysosomal enzymes

• -Anti host
• -GAS
• -Most important virulence factor
• -Adhesin: mediates attachment
• -Inactivates c3B no opsonization
• -Anti- M antibodies are protective (90+ types)

• -Anti host
• -GAS
• -Imp in adherence to throat epithelial cells

• -Anti host, GAS
• -Decrease PMN recruitment to the site of infection by neutrializing signal for chemotaxis

• -Anti host, GAS
• Responsible for beta hemolysis pattern
• SLO: damage cell membrane and mitral heart valves
• SLS: lyse bllod cells (RBC, WBC), toxic to liver and heart muscles

• -Anti host, GAS
• -Degrade connective tissue, including heart
• -Expressed at stationary phase of the growth cycle

• -Anti host, GAS
• Superantigen: cause massive activation of T cells nonspecifically
• -Family of toxins produced by strains that cause scarlet fever or necrotizing fasciitis
• -Spe A is phage encoded

• -Anti host, GAS
• -Helps organism spread within the infected tissue

• -Anti host, GAS
• -Dissolves blood clot which helps bacteria spread within tissue
• -Therapeutic use in stroke and heart attack patients

• -Anti host, GAS
• Post-infection sequelae- Virus, bacteria: signs and symptoms due to immuje system trying to get rid of teh remaining PG layer in the tissues

• -NO, cannot survive in PMN
• -Must be extracellular pathogens
• -Capusle and M protein protect them

• Only Strep. pyogenese (GAS) has M-protein
• -Role as adhesin
• degrades c3b and prevent opsonization

-only 10%, 1 of 10 carry, but may not always get sick

Infections starting from superfical epidermis (impetigo) and go deeper within the dermis (erysipelas) and subdermal area (cellulitis) and all the way into fascia (necrotizing fasciitis) and muscle and fat (myositis)

• Superficial infeciton of the skin over the face
• Not a necrotizing process
• Occurs in very young children
• Systemic signs (fever, chill, leukocytosis)
• Usually resolves completely with treatment with penicillin.
• Produces rash that is red, swollen, warm, tender, borders defined
• Up neutrophils

• GAS, acute pharyngitis or strep throat (GAS tonsillitis)
• -Mostly occur in young boys 5-15
• -Spread by respiratory droplets and fomites (school)
• -Prime strep throat season is cold season
• -Sore throat, fever, petechiae (Dark red spots)
• -White exudate on surface of throat
• -Must differentiate from viral pharyngitis (4 out of 5 are viral!)

• -Throat pain, difficult swallowing, red and swollen tonsils, white patches, swollen lymph nodes, fever, headache, stomachache.
• -Similar to sore throat by viral tonsillitis. NO white patches with viral.
• -Strep throat is not usually associated with a cough.
• A throat swab or rapid antigen test can determine if viral or bacterial

• -GAS
• -Erythematous rash with a sore throat
• -Exotoxin-mediated disease (SpeA)
• -Occurs most often in association with sore throat as a result of strep infections (18th century)
• -Symptoms: Red swollen throat with strawberry tongue,high fever over 101, erythematous rash
• A person can get more than once because 3 different types of Erythrogenic Toxin (Spe A, B, and C)

• -GAS
• -Flesh-eating bacteria
• -High risk: Weak immune system, chronic health problems (diabetes, cancer, kidney/liver disease), cuts in the skin, recent chickenpox or other viral infections that cause a rash, elderly, surgery, use of steroids b/c they lower the body's resistance to infection

• -Starts with a local infection at site of trauma, which spreads deep within the skin tissue and realse SpeA which gets in the blood
• -SpeA cause systemic symptoms
• -Toxin causes systemic shock
• -Mortality rate is high, about 30% (bactermia)
• -Patient dies of toxic shock
• -Amputation (removal) of affected area saves life

• -Anti M protein antibody is only protective antibody
• -Opsonic: bridges pathogen and pagocye
• -Fixes complement: calls phagocytes to the site
• -There are more than 90 strains of M-proteins

• -Penicillin stills works
• -Amoxicillin (pink medicine)
• -No vaccine available

• Children who come down with strep throat and still have their tonsils are more than 3x as likely to catch it again and again
• Surroudns tissue may still get infected but less severe

• -Post strep infection sequelae, GAS
• -A serious inflammatory condition that can affect many parts of the body-heart, joins, nervous system and skin
• -symptoms appear within 5 weeks after an untreated Strep throat infection.
• -One cause is similarities between strep antigens and heart valve proteins and heart muscle cells
• Secondly SLO: damage mitral heart valves
• -Occurs in children b/w 6-15
• -Major criteria is joint pain and swelling joint to joint (migrating polyarthritis) and inflammation of heart (pancarditiis)

• -Post strep infection sequelae, GAS
• -Occurs 10-14 days following strep skin infection
• -Acute, immune complex mediated inflammatory disorder of the glomeruli of kidneys.
• -Signs of kidney damage: hypertension and edema, with severe progessive renal failure
• -Uncommon sequela of acute infection
• -Most often in childhood ages 2-6

• -Causes problems in newborns
• -Strep. agalactiae
• -Positive CAMP test
• -B-hemolytidc
• -C carb of B kind on surface

• -Normal flora of vaginal tract (10-30% of pregnant women)
• -Group B is most common cause of sepsis (blood infection) and meningitis (#1) in newborns
• -Group B strep is most common infectious cause of death of newborns in USA
• -New born gets it during vaginal delivery from infected mother

-Immunocompromised (40% of all septicemias

• -Screen pregnant women and if positive, treat with antibiotics. IV antibiotics intrapartum (during labor)
• -Vaccine is now being explored in the US
• -Should give it to pregnant women who are positive, 6-8 before delivery

• -Nongroupable mixed hemolyic pattern. Many species: strep mutans, strep salivarius (oral flora).
• -Growth characteristics: Mostly a hemolytic and optochin-resistant

• -Viridans strep
• -Pathogeneiss of dental caries
• -Evolved receptors to help them stick to the tooth enamel and produce lactic acid as a byproduct of sugar
• -Transmitted from mother to offspring

-100% carriers, normal flora

• -Viridans
• -Strep. Subacute endocarditis
• -Opportunistic infeciton of the heart
• -Lesions of mouth (dental work) allow bacteria to enter the blood
• -Organism bind to damaged heart valves of people with Rheumatic fever

• -Dentists take medical history before dental work
• -Patient with history of RF must recieve penicillian a week before the dental work

• -SSEC is slower than acute, the bacteria grow on already damaged heart valves and cause more damange
• -GAS, the reason for heart damage is GAS toxins which reach the heart by way of blood as well as a person's immune system damage the healthy heart vavles

• -Group D Strep
• -Poop
• -Mixed hemolytic pattern: a or b
• -Strep faecalies or entercoccus faecalis

• - Normal flora of GI tract of human (10^7 per gram of feces) and animals
• -E. faecalis is the 3rd leading cause of nosocomial infections (1-staph, 2-E. coli)
• -Opportunitisic

• -Urinary tract infections (cath)
• -Nosocomial cause of subacute endocarditis
• -part of mixed microbial infecion following rupture of intestine
• -Stab wound, gunshot, rupture of appendix
• -Broad spectum

• -Extremely hardy and can survive for weeks on environemental surfaces
• -E. Faecalis has become one of the most troublesome hospital pathogens due to its intrinisic reistance to many antibiotics and a remarkable capacity for developing resistance to others.
• -Vancomycin Resistant Entercocci (VRE) are one of most important nosocomial pathogens
• -Quarter of enterococcus genome is made-up of mobile DNA and within these regions are genes for VRE and viruelence.
• -Great concern for transferring it to other bacteria such as staph aureus

• -Adherence, means the degree to which a patient correctly follows medical advice
• -An estimated half of those for whom meds are prescribed do not take them correctly
• -Lack of compliance results in: complications from chronic diseases, formation of resistant infections, untreated psychiatric illness

• Optochin: hemolysis a
• Bacitracin: B