What is the gram staining process?
1. Crystal violet dye plus iodine stains all bacterial cell walls
2. Alcohol extracts blue dye from lipid rich, thin-walled gram-negative bacteria
3. Red dye counterstains decolorized gram-negative bacteria
Describe gram-positive bacteria
-Rich in peptidoglycan
-retain violet dye
Describe gram-negative bacteria
-Poor in peptidoglycan
-counterstain with red dye
What is Ziehl Neelson stain used for?
Acid fast bacteria (red)
What is India ink stains used for?
What is Geimsa stain used for?
What is PAS used for?
What is Prussian blue stain used for?
What is Congo red stain used for?
What is osmic acid stain used for?
normal flora of the skin?
Potential skin pathogens?
Normal flora of the nasopharynx?
Streptococcus viridans, anaerobes
Potential pathogens of the nasopharynx?
Normal flora of the mouth?
Potential pathogens of the mouth?
Normal flora of the colon?
Potential pathogens of the colon?
Normal flora of the vagina?
Potential pathogens of the vagina?
Composes the inner layer of the cell wall of all bacteria?
-thick in gram-positive
-thin in gram-negative
-exception = Mycoplasma
Techoic acid forms the outer layer of the cell wall of which type of bacteria?
Lipopolysaccharide forms the outer layer of the cell wall of what type of bacteria?
-outer cell membrane = lipid bilayer
-also contains porins
What is special about mycobacteria cell walls?
Contain mycolic acid
What is special about Mycoplasma cell walls?
-It has no cell wall; membrane only
-only bacterium whose membrane contains cholesterol
Does penicillin work against Mycoplasma pneumonia?
No, penicillin attacks peptidoglycan and there are none
How are exotoxin neutralized?
What type of bacteria produce exotoxins?
Both gram-positive and gram-negative bacteria
What type of bacteria produce endotoxins?
-TNF, IL-1 → shock, fever
-toxoid used as vaccines
-usually heat labile
Which toxin is responsible for blocking the release of lysine leading to muscle spasms?
Which toxin is responsible for blocking the release of acetylcholine leading to muscle paralysis?
Which toxin inhibits protein synthesis by ADP ribosylation of EF-2?
Which toxin causes hemoloysis, necrosis, and cell death?
Alpha toxin → staph aureus
Which bacteria is responsible for toxic shock syndrome toxin?
Staph aureus → induces cytokine that produce anaphylactic shock
Which toxin stimulates adenylate cyclase activating GS protein?
Which toxin stimulates adenylate cyclase inhibiting GI protein?
What does the heat-stable E. coli enterotoxin do?
Stimulates at guanylate cyclase
Obligate anaerobic bacteria
most common cause of the common cold?
most common cause of pharyngitis and laryngitis?
Viral >bacterial (beta hemolyzing streptococci)
most common cause of tonsillitis?
beta hemolyzing streptococci
most common cause of otitis media?
Streptococcus pneumoniae, Haemophilus influenza
most common cause of sinusitis?
Streptococcus pneumoniae, Staphylococcus aureus
most common cause of pneumonia in infants?
most common cause of pneumonia in young adults?
most common cause of pneumonia in the elderly?
most common causes of bacterial meningitis in neonates?
-strep agalactica (GBS)
most common cause of bacterial meningitis in adults?
Neisseria Meningitidis >strep pneumoniae
most common cause of bacterial meningitis in the elderly?
Streptococcus pneumoniae >Neisseria Meningitidis
most common cause of endocarditis?
most common cause of carbuncle?
most common cause of sepsis In a catheterized patient?
most common cause of sepsis in a burn patient?
most common cause of diarrhea in children?
most common cause of diarrhea in adults in the US?
most common cause of diarrhea in travelers?
E. coli, Shigella, Salmonella
most common causes of genital ulcers?
most common cause of urethritis?
Chlamydia > gonococcus
most common cause of cystitis?
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