Gram Positive Pathogens - Robison Flashcards

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1
Q

Staphylococcus- General Facts

A

In every human’s microbiota

Can be oportunistic pathogens

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2
Q

What is the structure and physiology of Staphylococcus?

A

Gram positive cocci are non-motile, faculative aerobes, with irregular clusters

Catalase Positive

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3
Q

Describe S. epidermidis

A

most common organism on the surface of skin

coagulase negative, mannitol negative, and mostly opportunistic infections

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4
Q

Describe S.aureus

A

carried by 30-50% of healthy population

coagulase positive, mannitol positive, and more virulent

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5
Q

What are the three categories of Staphylococcal disease?

A

Non invasive - indegestion
Cutaneous - various skin conditions
Systemic

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6
Q

What are the Staphylococcal defenses against phagocytosis?

A

Inhibits the complement system by covering surface with protein A

Converts fibrinogen to fibrin with coagulase to not form blood clots; keeps its self surrounded by fibrin capsule

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7
Q

Which bacteria produces more toxins? S. aureus or S. epidermis?

A

S. aureus

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8
Q

What are cytolytic toxins?

A

pore forming toxins

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9
Q

What are exfoliative toxins?

A

causes skin cells to seperate from eachother

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10
Q

What are toxic- shock syndrome toxins?

A

causes toxic shock syndrome due to superantigen

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11
Q

What are some skin related diseases caused by staphylococus?

A

impetigo, boils (furuncle), carbuncle, scalded skin syndrome

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12
Q

What are some systemic diseases caused by staphylococcus?

A

TSS, bacteremia, endocarditis, pneumonia, osteomyelitis

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13
Q

Treatments for staphylococcus diseases

A

Methicillins for most infections

Vancomycin for MRSA

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14
Q

How are staphylococcus infections and diseases mostly passed?

A

endogenous source and easily transmitted by contact

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15
Q

What is the morphology and physiology of streptococcus?

A

Gram positive coccus arranged in pairs or chains

Aerotolerant anaerobes

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16
Q

What is in the Group A Streptococcus and what are characteristics?

A

S. pyogenes

pathogenic strains often form a capsule

can cause disease if the normal microbiota is depleted, large amounts develop, or specific immunity impaired

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17
Q

What causes pathogenicity in streptococcus Group A?

A

Protein M interferes with opsonization and lysis

Certain enzymes

Pyrogenic toxins stimulate macrophages and helper T cells to release cytokines

Streptolysins lyse RBC, WBC, and platelets

18
Q

What are some diseases caused by group A streptococcal?

A

phayngitis, scarlet fever, pyoderma, erysipelas, streptococcal TSS, necrotizing fasciitis, rheumatic fever, glomerulonephritis

19
Q

How is GAS transmitted?

A

respiratory droplets, direct, and indirect contact

20
Q

What are some characteristics of streptococcus pneumoniae?

A

Gram positive cocci that mostly forms in pairs but also can form chains

usually colonizes in the mouth and phayrnx bu can cause disease if in the lungs
Disease is the highest in the children and elderly

21
Q

What is the most significant human pathogens?

A

streptococcus pneumoniae

22
Q

What is the pathogenicity of streptococcus pneumoniae?

A

polysaccharide capsule that binds factor H to inhibit the complement pathway

protein adhesin helps binding to cells

Secretory IgA protease

pneumolysin is a pore forming toxin

23
Q

What are some diseases that streptococcus pneumonia can cause?

A

pneumococcal pneumonia

sinusitis and otitis media

bacteremia and endocarditis

pneumoccal meningitis

24
Q

What is the diagnosis, treatment and prevention of streptococcus?

A

Diagnosis: gram stain of sputum smears
Treatment: penicillin or cephalosporins
Prevention: vaccines

25
Q

What are enterrrococcus?

A

found in the human colon

Short chains and pairs that lack a capsule but can grow in basic conditions

resistant to mobt beta-lactams, sulfa drugs, and VRE, erythromyocin, and tetracycines

26
Q

What are characteristics of bacillus?

A

Gram positive bacilli that occur in pairs, singles, or chains
forms endospores

27
Q

What is anthrax?

A

gram positive endospore forming bacillus

has three component toxin

28
Q

What are the three forms of disease of anthrax in a human?

A

Inhalation- causes capillary thrombosis and cardiovascular shock
Gastrointestinal- ingestion of spore; rare
Cutaneous- marked by necrotic skin ( eschar); usually not fatal

29
Q

What is the diagnosis, treatment, and prevention of anthrax?

A

Diagnosis- presence of non motile gram-positive bacilli in lungs or skin
Treatment- ciproflaxacin and other antimicrobials
Prevention: animal control and vaccines

30
Q

What are characteristics of clostridium?

A

gram positive anarobic endospore forming bacilli

31
Q

Describe characteristics of clostridium perfringens

A

Usually in digestive tracts
Produces 11 toxins
Causes food poisoning and gas gangrene

32
Q

What are the treatments for gas gangrene?

A

removing dead tissue and admistering large doese of penicillin and hyperbaric oxygen

prevent with proper cleaning and prevent gas gangrene

33
Q

What is botulism?

A
Disease caused by clostridium
Flaccid paralysis 
treatment is polyvalent antitoxin 
Prevented by proper food preparation and storage procedures 
Toxin is destroyed by heat
34
Q

What are the three forms of botulism?

A

Food-borne
Infant
Wound

35
Q

What is clostridium tetani and what does it cause?

A

Endospore forming obligate anaerobic gram positive rod

causes tetanus - spasms and contractions that can result in death “lock jaw and spastic paralysis”

treated with vaccines

36
Q

Describe bacteroides fragilis

A

Easiest to grow with a polysaccharide capsule

anaerobes

37
Q

Describe Listeria monocytogenes

A

Anaerobes

gram positive; non spore forming

can live within cells, doesnt form toxins

resistant to heat, cold, salt, and pH

infections are caused by ingestion of contaminated milk or meat

Treated with ampicillin and prevented by pasteuriationa and proper cooking

38
Q

What is corynebacterium and what does it cause?

A

On plants, animals, and humans

colonized in skin respiration, GI, urinary, and genital tract

Causes diptheria

39
Q

How is diptheria transmitted and what are its symptoms?

A

through respiratory drops and skin contact; diptheria toxin causes symptoms

Causes dead cells and fluid to thicken and harden in the respiratory tract

cutaneous diphtheria causes cell death

Can also cause damage to heart and CNS;

40
Q

What is the Schick test?

A

test immunity to diphtheria

41
Q

What is propionibacterium and what does it cause?

A

Small, Gram-positive rods that are found in the skin

Causes acne

42
Q

Describe actinomyces

A

anaerobic gram positive filamentous bacilli

found in dental plaque

treat with amoxicillin