Microbiology

Which species of bacteria have AB toxins? ------ Vibrio cholera and Bacillus cereus (AB5) Corynebacterium diptheriae (AB) What are three anti-cholingergics that penetrate the blood-brain barrier? ------ Pilocarpine, physostigmine, and parathion Name several cholinomimetics (meaning drugs that act as muscarinic agonists). What is unique about these drugs? ------ Bethanechol Carbachol Pilocarpine Methacholine They are unique because they are not degraded by acetylcholine esterase Name several cholinesterase inhibitors. ------ Tacrine (similar to donepezil, rivastigmine, and galanthamine) Parathion (and other organophosphates) Edrophonium Pyridostigmine Physostigmine Neostigmine Name two muscarinic antagonists. Which is used more systemically? ------ Atropine and Ipratroprium. Atropine used more systemically, whereas Ipratroprium is used mainly as an M3 antagonist in the treatment of asthma and COPD to decrease respiratory secretion and decrease bronchoconstriction. What is the only Gram positive bacterium with endotoxin? What does this bacterium have in common with Streptococci? How will you tell them apart. ------ Listeria monocytogenes has endotoxin. It is also beta-hemolytic, similar to Streptococci. You will distinguish them with catalase testing, as L. monocytogenes is catalase positive, whereas all Streptococci are catalse negative. What is the only Gram negative bacterium without typical endotoxin? ------ Bacteroides What would be some containdications to the use of Bethanechol? ------ Bethanechol is a systemic muscarinic agonist, so contraindications would be asthma (due to increased bronchoconstriction and bronchosecretions), AV nodal heart block (muscarinic agonist will slow AV nodal conduction), heart failure (due to decreased myocardial contractility with muscarinic agonist). What is the difference between wide and narrow angle glaucoma? ------ Narrow angle glaucoma occurs when the iris partially blocks the trabecular meshwork of the eye, preventing drainage of aqueous humor. Wide angle glaucoma occurs when you just have poor tone of the trabecular network, and this no physical impedement to aqueous humor outflow. What is the difference between Physostigmine and Pyridostigmine? ------ Physostigmine is used to treat glaucoma, and it crosses the BBB. Pyridostigmine is used in the treatment of myasthenia gravis. Describe the Tensilon Test. ------ Tensilon (Edrophonium) is an extremely shortacting inhibitor of acetylcholinesterase. It is used to distinguish cholinergic crisis (due to overmedication) from worsening symptoms (undermedication) in myasthenia gravis. Edrophonium will worsen a crisis, but improve symptoms of undermedication. What are the symptoms of organophosphate poisoning? How is it treated? ------ Diarrhea, loss of visual acuity due to ciliary body paralysis, increased secretions (tears, bronchosecretions, salivation, sweating), coma, seizures, respiratory depression, muscle twitching, weakness, flaccid paralysis. To treat the poisoning, you must administer a cholinesterase regenerator (Pralidoxime) before the organophosphates "age". Administer emetics, perform gastric lavage, give activated charcoal, administer atropine. You have just brought a patient out of the operating room. What will you administer as they are coming out of anesthesia, and why? ------ Neostigmine reverses non-depolarizing neuromuscular blockade, which will counteract the paralytic agent that was administered before surgery. Neostigmine will also help

treat any possible neurogenic ileus or bladder that may result from surgery on the gut. Which species of Gram + bacilli are spore-formers? ------ Clostridia and Bacilli Which species of Gram + Bacilli are non-spore-formers? ------ Listeria and Corynebacterium How would one distinguish Bacilli from Clostridium? ------ Clostridium species are obligate anaerobes, whereas bacillus species are aerobes. How would one distinguish between the speces of Bacillus (Gram +, spore-forming, aerobic bacilli)? ------ B. cereus is motile, whereas B. anthracis is non-motile How would one distinguish between the species of Clostridium? ------ C. perfringens is the only non-motile one; all the others are motile. How would one distinguish between the non-spore-forming, Gram + bacilli (and they are...?) ------ Listeria monocytogenes and C. diphtheriae; Listeria is motile, whereas Corynebacterium is not. How do you tell Staph from Strep? ------ Catalse test (Staph are positive, Strep are negative) How would one distinguish between the Staphylococcus species? ------ S. aureus is the only coagulase + one; S. epidermidis and S. saprophyticus are coagulase negative. S. epidermidis is novobiocin sensitive, whereas S. saprophyticus is novobiocin resistant. What two Strep species are beta-hemolytic? How do you tell them apart? ------ S. pyogenes and S. agalactiae, and you tell them apart because S. pyogenes is bacitracin-sensitive, whereas S. agalactiae is bacitracin-resistant. What two Strep species are alpha-hemolytic? How do you tell them apart? ------ S. pneumoniae and Viridans Strep are both alpha-hemolytic, and you can distinguish them by using optochin. Viridans is optochin-resistant, whereas S. pneumoniae is optochin-sensitive. S. pneumo also has a capsule (and thus a positive Quellung reaction) whereas Virdians Group Strep are acapsular. Which Strep species are non-hemolytic or have mixed hemolysis? ------ S. bovis, Enterococcus Faecalis, and Peptostreptococcus. What is Peptostreptococcus? ------ An anaerobic Gram positive organism usually classified with Strep that has mixed or no (gamma) hemolysis and is commonly found in mixed infections. What are the virulence factors of S. aureus? ------ Protein A (binds Fc portion of IfG), coagulase (forms fibrin coat around the organism), hyaluronidase (breaks down host connective tissue), lipase (breaks down host fat) What are the disease-causing toxins of S. aureus? ------ TSST-1 (Toxic Shock Syndrome), Exfoliative toxins A and B (Scalded Skin Syndrome) and Enterotoxin (food poisoning) What underlying disease would one be concerned about if a patient tested positive for Strep bovis? ------ colon cancer (or less likely, inflammatory bowel disease) What are some pathologies caused by Viridans Streptococci? ------ Dental caries, brain or abdominal abscesses, and subacute bacterial endocarditis What are the clinical features that distinguish atypical pneumonia from typical pneumonia? ------ Typical pneumonia usually has rapid onset of fever, chills, productive cough with rusty-colored sputum, and a lobar presentation on CXR. Atypical pneumonia's onset is often more insidious, cough tends to be dry, CXR reveals fluffy, diffuse infiltrates. What are some of virulence factors of S. pneumo? What diseases does S. pneumo cause? What type of patients are especially susceptible to S. pneumo? ------ Antiphagocytic capsule and IgA proteases. S. pneumo causes otitis media, pneumonia, and meningitis, mostly all in adults. Asplenic patients are especially susceptible to S. pneumo. Which organisms that cause food poisoning have the most rapid onset? ------ S. aureus and B. cereus What kind of paralysis is associated with C. botulinum? What kind of paralysis is associated with C. tetani? What kind of a paralysis is associated with GuillanBarre Syndrome? ------ Botulism=flaccid decending paralysis due to ACh release

blockage. Tetanus=rigid paralysis due to inhibition of GABA release. GuillanBarre=ascending flaccid paralysis. Which muscarinic agonists are metabolized by AChE? Which are not? ------ ACh and Methacholine are hydrolized by acetylcholinesterase. Pilocarpine and Bethanechol are not hydrolyzed. What are the 3 muscarinic receptor antagonists? ------ Atropine, Scopolamine, and Ipratroprium Where are the M1 muscarinic receptors? M2 muscarinic receptors? M3s? ------ M1s in the CNS, M2s in the cardiovascular system, and M3 is in the lung, GI tract, GU tract, and eye Where are nicotinic receptors? ------ First synapse sympathetic, first synapse parasympathetic, synapse on the adrenal medulla, synapse on the skeletal muscles What are the effects of nicotine? ------ Nicotine is a ganglionic stimulant at low doses and a ganglionic blocker at high doses, so it binds to nicotinic receptors at low doses and blocks sympathetic and parasympathetic output. Increased heart rate, increased BP, increased GI motility. What are three cholinergic synapses? ------ Second parasympathetic muscarinic synapse (plus sweat and salivary glands for sympathetic system); Neuromuscular junction nicotinic receptor; ganglionic nicotinic receptor for the first synapse of parasympathetic and sympathetic. What are the genera of Gram positive cocci? ------ Staphylococcus, Streptococcus, and Enterococcus Post-streptococcal acute glomerulonephritis and rheumatic fever are both complications of infection with S. pyogenes. What is the difference in the pathogenesis of these two diseases? ------ Post-streptococcal acute glomerulonephritis occurs when circulating immune complexes are deposited in the glomeruli, triggering an inflammatory reaction. Rheumatic fever occurs when the antibodies made against the S. pyogenes bacterial antigens cross react with heart valves and and joint tissue. What types of infections are caused by S. aureus? ------ impetigo, cellulitis, furuncle, carbuncle, pneumonia, acute endocarditis, osteomyelitis, septic arthritis, meningitis What is the difference between S. aureus and other Staphylococcal species? ------ S. aureus is coagulase + and it produces exotoxin. S. aureus colonies will be yellow, while the other Staph species will grow white colonies. How do S. epidermidis and S. saprophyticus differ? How are they similar? ------ S. epidermidis is novobiocin-sensitive, whereas S. saprophyticus is novobiocin-resistant. S. epidermidis may cause a variety of infections in the immunocompromised or recently surgerized person, whereas S. saprophyticus is known solely as a pathogen responsible for urinary tract infections. Which drug is used to treat status asthmaticus? ------ Terbutaline What drugs are used to treat preterm labor? ------ Ritodrine and terbutaline Why is it a bad idea to abruptly stop clonidine? ------ Because it may result in rebound hypertension Of the three Gram-negative respiratory pathogens, which is NOT spread person-toperson? ------ L. pneumophila What are the growth requirements of H. influenzae? ------ NAD and Heme What are some of the pathologic effects of B. pertussis? ------ Cilliary paralysis; inactivation of the Gi subunit of cAMP system, which promotes secretions; tracheal cytotoxicity What are the nutritional requirements for L. pneumophila to grow on culture? ------ Iron and cysteine What bacterial organisms produce IgA proteases? ------ H. influenzea, S. pneumoniae, N. meningitidis What is the important thing to know about the structural feature of Mycoplasma species? ------ NO CELL WALL: cholesterol-padded membranes What are the hallmarks of infection with Mycoplasma pneumoniae? ------ Streaky chest x-ray that looks worse than the person's presentation would suggest

Name three bacterial species that can produce urethritis. ------ Ureaplasma urealyticum, N. gonorrheae, C. trachomatis Which infectious agents cause a rash on the palms and soles? ------ Coxsackie virus, Rocky Mountain Spotted Fever, Typhus (trunk rash first), syphilus Which infectious agents cause desquamation of palms and soles? ------ S. aureus (TSS), S. pyogenes (scarlet fever) What diseases present with migratory arthritis? ------ Colitic migratory arthritis, gonoccocal disease, Lyme Disease, Rheumatic Fever Name two obligate intracellular bacterial parasites. ------ Chlamydia and Rickettsia What are some causes of dilated cardiomyopathy? ------ Pregnancy, doxyrubicin, hypertension, alcohol abuse