Infectious Diseases Flashcards
What are the 3 categories of skin flora
Diphtheroids
Staphylococci
Yeasts
Example of diphtheroid
Propionibacterium acnes
What causes hair follicle infections
Staph aureus
Causes scalding skin syndrome
Staph aureus
Causes impetigo
Step pyrogenes
Causes rocky mountain spotted fever
Rickettsia rickettsii
Causes Lyme disease
Borrelia burgdorferi
How does s aureus avoid host defenses
Has a capsule that prevents phagocytosis
Produces enzymes that degrade tissue
What is folliculitis
Follicle plugged with necrotic tissue
What does inflammation response signal
Attraction of neutrophils
What happens if an infection spreads to adjacent tissue
An abscess forms
What is a small skin lesion called
Furuncle
What is a skin lesion called when it involves multiple follicles
Carbuncle
How do you treat hair follicle infections
Drain boil
Antibiotics
What is s aureus resistant to
Penicillin
What is streptococcal impetigo
Superficial skin infection involving epidermis
From infected non apparent wound
What is a key detail of impetigo
Blisters that break and release plasma
The plasma looks yellow when dry
Details about step pyogenes
Gram pos
Beta hemolytic
Group A
Produces extra cellular products
What can s pyogenes be treated with
Penicillin
Why is s pyogenes called group A strep
Group A cell wall polysaccharide
What is a product pyogenes can produce
Protease
Flesh eating
Causes measles
Rubeola virus
Causes rubella or German measles
Rubella virus
Causes fifth disease
Parvovirus b 19
Causes roseola
Herpesvirus type 6
What causes varicella
Varicella zoster virus
How is chickenpox transmitted
Respiratory secretions and skin lesions
What is incubation of varicella
When is it infective
2 weeks
Infective 1-2 days before rash until they crust over
Describe pathogenesis of varicella
Enter through respiratory route Reliplicates and moves to skin via blood stream Infects living layers of skin Moves to adjacent cells causing lesions Cells lyse Release virus to sensory nerves
What is shingles
Latent infection
Herpes zoster
What allows herpes zoster virus to replicate
Decline in cell mediated immunity
Old age or immunocompromised
Shingles appears in what area
Anywhere
Restricted to area supplied by a sensory nerve
How does body respond to shingles
Inflammation reaction
Memory cells respond
Shingles disappear
What cause cutaneous mycoses
Dermatophytes
What do dermatophytes do
Dissolve keratin in skin for nutrients
What are the 6 steps of wound repair
Vascular spasm to prevent blood loss
Circulating platelets form plug to seal wound
Coagulation
Fibroblasts multiply and form granulation tissue
Granulation tissue is replaced
What type of clotting factors are circulating in blood
Inactivated clotting factors
Like inactivated fibrogen
What causes clotting factors to become activated
Tissue damage
What does fibrinogen convert to
And what causes it to convert
Fibrinogen becomes fibrin
The activation of clotting factors converts fibrinogen
What does fibrin do
Form a mesh
What digests fibrin mesh
Plasmin
Where does plasmin come
Inactivated plasminogen is convert to active plasmin by tissue plasminogen activator
What is pus
Dead neutrophils microorganisms and degraded tissue
Pyogenic means
Pus forming
Pyrogenic means
Fever forming
What helps separate an abscess from normal tissue
Inflammation and clots
Why can having a walled of abscess be bad
It can prevent antimicrobials from reaching the area
Pressure can increase and pathogens can go into blood stream
Area become anaerobic
Are pathogens actively multiplying in an abscess
No
They are not multiplying
What are 4 common bacteria that infect wounds
Staph aureus
Staph epi
Step pyogenes
Pseudomonas eaeuginosa
What is the leading cause of woud infections
Staphylococci
What factors increase the virulence of staph aureus
Coagulase causes clotting to evade phagocytosis
Clumping factor aids in attachment to fibrin
Protein A hide bacteria
Alpha toxin produces hole in host cell membrane
What do staph epi do
Sometimes produce biofilm to prevent phagocytosis
How do you treat wound infections
Methicillin or vancomycin
What does not have a lot of antimicrobial resistance
S pyogenes
Can be treated with penicillin
What are some severe infections caused by streptococci
Pneumonia
Meningitis
Puerperal
Necrotizing fasciitis
What is puerperal
Childbirth fever
Bacterial infection of uterus
What causes necrotizing fasciitis
2 virulent s pyogenes strains
2 extra cellular products produced
Pyrogenic exotoxin A
Exotoxin B
Describe the pathogenesis of necrotizing faaciitis
Colonization enhanced by tissue binding proteins
Subcutaneous fascia is destroyed
Muscle tissue can also be destroyed
Organisms multiply and produce toxins
Organisms and toxins enter blood stream and cause shock
What does pryogenic exotoxin A do
Cause streptococcal toxic shock
What does exotoxin B do
Destroy tissue trough protein breakdown
How do you treat necrotizing faaciitis
Surgery to prevent toxin spread
Maybe amputation
Penicillin if given early doesn’t help against toxins or dead tissue
What is an opportunistic wound pathogen
P aeruginosa
What is p aeruginosa the major cause of
Specifics
Nosocomial infections
Lung infections from contaminated respirator water
Burn infections that turn skin green
What makes aeruginosa virulent
Toxins
And multi drug resistance
Some examples of anaerobic wound infections
Tetanus
Gas gangrene
Lumpy jaw
What causes tetanus
Clostridium tetani
Causes gas gangrene
Clostridium perfringens
Causes lumpy jaw
Actinomycosis israelii
Gram pos filamentous anaerobe
What are the symptoms of tetanus
Painful uncontrolled muscle spasms
Often start with jaw
Describe clostridium tetani
Gram pos
Anaerobe
Rod shaped
Endospore forming
Is tetanus fatal
Yes not in developed world though
Why is tetanus pathogenic
Due to toxin production
What is the path that tetanus toxins take
Blood stream to CNS
What do tetanus toxins do
Block inhibitory neurons so muscles spasm
If inhibitory neurons of brain first affected jaw spasms firsts
Why does tetanus cause death
Paralysis of respiratory muscles
Stomach contents go into lungs
What is tetanus vaccine
Inactivated toxin
What is passive tetanus immunity
Tetanus antibodies
Tetanus immune globulin
What causes swelling in gas gangrene
Gas production
Tissue breakdown
Describe c perfringens
Gram pos Anaerobic Rod Endospore forming In soil
What does c perfringens produce
Alpha toxin which attacks host membranes
Spreads in blood stream leads to red blood cell destruction
What are the areas of upper respiratory system
Ear Eye Sinuses Nasal cavity Tonsils
What are tonsils made of
Lymphoid tissue
What is the role of the mucociliary escalator
Cilia propels mucus up so you can swallow it
Where does the lower Respitory system start
Below epiglottis
What does lower respiratory system include
Larynx Trachea Bronchi Bronchioles Alveoli
What is pneumonitis
Inflammation of lungs
What is pneumonia
Filling of alveoli with pus and fluid
List upper respiratory beacterial infections
Strep throat Pinkye Diphtheria Otitis media Sinus infections
List lower respiratory bacterial infections
Pneumonia
Whooping cough
Tuberculosis
Legionnaires disease
What is strep throat
Streptococcal pharyngitis
What is strep throat caused by
Step pyogenes
Group A
What are 3 complications of strep throat
Scarlet fever
Acute rheumatic fever
Acute glomerulonephritis
What antibiotics treat step throat
Penicillin
Erythromycin
Upper respiratory viral infections
Common cold
Adenovirus sore throat
Lower respiratory viral infections
Influenza
Viral pneumonia( SARS )
Respiratory syncytial virus
Hantavirus pulmonary syndrome
What causes common cold
Rhinovirus
How does rhinovirus infect
Attaches to receptors on respiratory epithelial cells
Multiplies in those cells
Releases more viruses
What causes nasal secretions of cold
Inflammation of injured epithelial cells