General Microbiology Short Review Guide

General Microbiology Short Review Guide
Question	Answer
Staphylcoccus aureus can be differentiated from other staphylococcus species by using what test?	Coagulase test; S. aureus is the only Staph that is coagulase positive.
What kind of media does Neisseria grow on?	Chocolate agar or SBA.
What is a good way to differentiate staph from strep species?	Catalase test. The catalase test will always be positive for catalase.
What reagent does the catalase test use?	H2O2 (Hydrogen peroxide)
Describe the appearance of Neisseria species when using gram's stain.	Gram negative diplococci
What is unique about the appearance of Neisseria gonorrhaeae when stained w/ gram's stain?	It appears kidney bean shaped.
What does capnophilic mean?	Carbon dioxide loving.
Why would a colony on sba not be preferred for a catalase test?	RBC's produce catalase and could give a false positive.
What type of media is Mannitol Salt Agar (MSA)?	Selective and differential for S. aureus.
Name the coagulase negative staph that is of particular concern to women of child bearing age.	S. saprophyticus; causes UTI
Name the coagulase negative staphylococci of clinical importance.	Staph saprophyticus and S. epidermidis.
Name a test that can differentiate the clinically significant coagulase neg staph.	Novobiocin disk; S. saprophyticus is resistant to novobiocin. Staph epidermidis is susceptible.
What manual tests can distinguish between group D strep and enterococcus species?	Bile esculin, NaCl 6.5%, and PYR. Group D strep is negative for all of these tests. Enterococcus species cause H2S precipitation in the bile esculin tube and is positive PYR and 6.5% NaCl.
What are some virulence factors of group A strep?	Capsule and M-protein (antiphagocytic).
What is a macroscopic indication that you have a Rothia species?	It is very sticky and adheres to the plate.
Which enterotoxins are common causes of food poisoning? Why are they so pathogenic?	Enterotoxin A and D. They are heat stable which means they don't degrade as easily as other toxins.
What is the most common alpha-hemolytic strep?	Strep. pneumoniae
What population of people are commonly affected by toxic shock?	Young menstruating women.
What are the symptoms of toxic shock?	High fever, hypotension, and shock.
What are the symptoms of food poisoning from S. aureus?	Abd pain, nausea+vomiting, severe cramping, dehydration, and possible headache.
Who would normally have scalded skin syndrome and what causes it?	Newborns and young children; caused by exfoliative exotoxin produced by staph aureus.
If a patient that was 19 years old came in complaining of a stiff neck, fever, and frontal headache; what would you suspect? How would you treat it?	Neisseria meningitidis; Penicillin
How can you differentiate between Neisseria meningitidis and Neisseria gonorrhoeae?	CTA sugars testing. Neisseria gonorrhoeae with only be positive on glucose, N. meningitidis will be positive for glucose and maltose. Also the superoxyl test can be used. Gonorrhea will have vigorous bubbles but meningitidis will be less prominent.
What is waterhouse-friderichsen syndrome and what organism causes it?	It combination of adrenal gland hemorrhage and petechial skin rash; Neisseria meningitidis
Name some things that contribute to the virulence of Neisseria meningitidis.	Pili, polysaccharide capsule, and endotoxin (lipopolysaccharide).
What are the labs like for a person suffering from toxic shock?	DIC (disseminated intravascular coagulation), decreased platelets, increased WBC (bands and metas), increased creatinine.
How can you tell if a specimen is a staph species?	Gram stain, MSA plates (mannitol salt agar), Catalase test, sensitivity tests (novobiocin, bacitracin)
How can you differentiate between S. saprophyticus and S. epidermidis?	Novobiocin susceptibility test (S. saprophyticus is resistant and S. epidermidis is sensitive).
Name tests that could identify group B strep.	Hippurate, CAMP
What antibiotic is group A strep susceptible to?	Penicillin
What antibiotic is groups A, C, and G susceptible to?	Bacitracin
Name a group A strep.	Streptococcus pyogenes.
Which groups of strep produce beta hemolysis?	A,B,C,F,G
Name group D streptococcus species.	S. bovis, E. faecalis, and E. faecium.
If S. bovis is found in the blood stream what does it indicate?	Colon cancer.
What kind of hemolysis is expected from group D strep?	Alpha mostly; but can rarely be beta or gamma.
Where in the body are group D strep found?	Normal flora of GI and genitourinary tract (GU).
Where would a viridians strep be found in an infected patient?	usually in the blood (bacteremia) or on heart valve replacements. Often can cause endocarditis.
What is a special nutrient requirement of viridans strep?	Must have B6 and thiol
Which viridans strep causes dental caries?	S. mutans
What test can indicate that a patient is infected with S. pneumoniae?	Optichin test; S. pneumo is susceptible.
How can you differentiate between S. bovis and Leuconostoc species?	Leuconostoc species grow in 6.5% NaCl but S. bovis does not.
What would show up as GP diplococci that are lancet shaped?	S. pneumo
What is a common symptoms of gonorrhea?	Urethritis, cervicitis, PID, pharyngitis, proctitis or possibly no symptoms at all (50% of fems have no symptoms).
What is it called when a baby gets gonorrheal conjunctivitis from the birth canal?	Ophthalmia neonatorum.