Gram Positive Pathogens - Robison Flashcards by Stephanie Sue

Staphylococcus- General Facts

In every human’s microbiota

Can be oportunistic pathogens

How well did you know this?

Not at all

Perfectly

What is the structure and physiology of Staphylococcus?

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

Catalase Positive

How well did you know this?

Not at all

Perfectly

Describe S. epidermidis

most common organism on the surface of skin

coagulase negative, mannitol negative, and mostly opportunistic infections

How well did you know this?

Not at all

Perfectly

Describe S.aureus

carried by 30-50% of healthy population

coagulase positive, mannitol positive, and more virulent

How well did you know this?

Not at all

Perfectly

What are the three categories of Staphylococcal disease?

Non invasive - indegestion
Cutaneous - various skin conditions
Systemic

How well did you know this?

Not at all

Perfectly

What are the Staphylococcal defenses against phagocytosis?

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

How well did you know this?

Not at all

Perfectly

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

S. aureus

How well did you know this?

Not at all

Perfectly

What are cytolytic toxins?

pore forming toxins

How well did you know this?

Not at all

Perfectly

What are exfoliative toxins?

causes skin cells to seperate from eachother

How well did you know this?

Not at all

Perfectly

What are toxic- shock syndrome toxins?

causes toxic shock syndrome due to superantigen

How well did you know this?

Not at all

Perfectly

What are some skin related diseases caused by staphylococus?

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

How well did you know this?

Not at all

Perfectly

What are some systemic diseases caused by staphylococcus?

TSS, bacteremia, endocarditis, pneumonia, osteomyelitis

How well did you know this?

Not at all

Perfectly

Treatments for staphylococcus diseases

Methicillins for most infections

Vancomycin for MRSA

How well did you know this?

Not at all

Perfectly

How are staphylococcus infections and diseases mostly passed?

endogenous source and easily transmitted by contact

How well did you know this?

Not at all

Perfectly

What is the morphology and physiology of streptococcus?

Gram positive coccus arranged in pairs or chains

Aerotolerant anaerobes

How well did you know this?

Not at all

Perfectly

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

S. pyogenes

pathogenic strains often form a capsule

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

How well did you know this?

Not at all

Perfectly

What causes pathogenicity in streptococcus Group 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

What are some diseases caused by group A streptococcal?

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

How is GAS transmitted?

respiratory droplets, direct, and indirect contact

What are some characteristics of streptococcus pneumoniae?

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

What is the most significant human pathogens?

streptococcus pneumoniae

What is the pathogenicity of streptococcus pneumoniae?

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

What are some diseases that streptococcus pneumonia can cause?

pneumococcal pneumonia

sinusitis and otitis media

bacteremia and endocarditis

pneumoccal meningitis

What is the diagnosis, treatment and prevention of streptococcus?

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

What are enterrrococcus?

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

What are characteristics of bacillus?

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

What is anthrax?

gram positive endospore forming bacillus has three component toxin

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

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

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

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

What are characteristics of clostridium?

gram positive anarobic endospore forming bacilli

Describe characteristics of clostridium perfringens

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

What are the treatments for gas gangrene?

removing dead tissue and admistering large doese of penicillin and hyperbaric oxygen prevent with proper cleaning and prevent gas gangrene

What is botulism?

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

What are the three forms of botulism?

Food-borne Infant Wound

What is clostridium tetani and what does it cause?

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

Describe bacteroides fragilis

Easiest to grow with a polysaccharide capsule anaerobes

Describe Listeria monocytogenes

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

What is corynebacterium and what does it cause?

On plants, animals, and humans colonized in skin respiration, GI, urinary, and genital tract Causes diptheria

How is diptheria transmitted and what are its symptoms?

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;

What is the Schick test?

test immunity to diphtheria

What is propionibacterium and what does it cause?

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

Describe actinomyces

anaerobic gram positive filamentous bacilli found in dental plaque treat with amoxicillin