A
What are the 4 ways to classify bacteria?
1. Gram Stain
2. Morphology
3. Metabolic Activity
4. Virulence Factors
What is the best way to determine which Antibiotic to use?
Culture and sensitivity (Gram Stain will give you an idea of which broad ABx to start with but only sensitivity will tell you which targeted ABx will work.)
Where are the most common places to culture for bacteria in a patient?
1. Sputum (Pneumonia, TB or lung abscess)
2. Spinal Fluid (Meningitis, encephalitis, abscess, empyema)
3. Wounds
4. Urine
What is considered a good sputum sample?
>25 WBC's present and <10 epithelial cells present.
If you suspect Mycobacteria, what stain should you use?
Acid fast stain (reacts with fatty mycolic acid of the cell wall)
What is the best way to see chlamydia, C. trachomatis?
Look for Inclusion Bodies in the cytoplasm.
Gram doesn't work because they are too small and INTRACELLULAR.
What is the difference between endotoxin and exotoxin?
Endotoxin: is a part of the outer LPS layer of G- bacterial cell walls. When a cell dies, the endotoxin is released causing a toxic effect on the surrounding tissue. Makes the G- bacteria toxic, as a opposed to the bacteria releasing a toxin.
Exotoxin: Something secreted by the bacteria that inflames and destroys adjacent tissue
How are cell membranes of fungi different from those of bacteria?
They are bi-layered and contain sterols.
There is a cell wall.
There is an outer polysaccharide capsule (virulence).
What parts of the body are normally sterile?
Urinary bladder
Peritoneal cavity
Pleural cavity
Pericardial cavity
What are the 5 main types of pathogens?
Bacteria
Fungi
Parasites
Protozoa
Prions
What are the 3 major structures of a virus?
1. Core- where nucleic acid is
2. Capsid- protein coat
3. Envelope- lipoprotein membrane (not all viruses)
What are the 4 cardinal signs of inflammation?
Rubor (redness)
Tumor (swelling)
Calor (heat)
Dolar (pain)
What is an infectious dose?
# of organisms required to cause disease.
Ex: shigella <100 orgs, salmonella = 100k
What is biofilm?
An extracellular polysaccharide network that protects the pathogen from the human immune system- mechanical scaffold around bacteria.
What bacteria causes toxic shock?
Staph aureus
What is the provider's role in immunization?
Proper storage and administration
Correct timing/spacing of vaccine doses
Observation of contraindications/precautions
Reporting to VAERS
What is cytopathic effect (CPE)?
The alteration of host cell structure/ function caused by the virus that causes death of the cell.
What 3 things can cause a SECONDARY ACQUIRED IMMUNODEFICIENCY?
Malnutrition - you need diet/rest/exercise to be healthy
Medical Tx of other Diseases:
Cytotoxic agents
Corticosteroids
Radiation
Infection, neoplasm or Splenectomy
What are the ISOLATION PRECAUTIONS for MRSA?
Contact isolation
What type of Infections are post splenectomy patients susceptible to?
ENCAPSULATED ORGANISMS
Neiserria
Strep. Pneumo
H. Flu
What are the 5 prion-caused diseases in humans?
Creutzfeldt-Jakob Disease (Mad Cow)
Variant CJD
Kuru (shivering)
Gerstmann-Sträussler-Scheinker Disease (GSS)
Fatal Familial Insomnia (FFI)
What body fluids are not considered "infectious"?
Feces
Urine
Sputum
Saliva
Sweat
Tears
Vomit
What bacteria use enterotoxin that results in explosive infectious diarrhea?
Vibrio Cholera
Shigella dysenteriae
E. Coli
Campylobacter jejuni
Bacillus Cereus
What pathways do endotoxin activate?
Macrophages (IL-1, TNF, NO) → Fever/ hypotension
Hageman Factor X → Coag cascade →
Complement (C3a, C5a) → Hypotension, Edema, Neutrophil
Which fungi has an outer polysaccharide capsule and causes CNS dysfunction?
Cryptococcus Neoformis