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478 Cards in this Set

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T/F E. Coli ferments lactose?
TRUE;
These E. Coli are responsible for travelers diarrhea and children's diarrhea?
ETEC
This E.coli shows bacillary dysentary similar to shigella?
EIEC
This E. Coli shows infant diarrhea?
EPEC; also EAEC
This E. Coli produce shiga toxin and displays hemorrhagic colitis and Hemolytic Uremic Syndrome?
EHEC/STEC
What are the steps of pathogenesis for ETEC?
ingestion (food/water - human feces) > colonization small intestine (colinization fimbria CFA and CS) > elaboration of enterotoxins (ST and LT)
ETEC (watery diarrhea or inflammatory diarrhea)?
Watery
CF, LT and ST genes (virulence factors) are encoded where in ETEC?
Large plasmids
What is the mechanism of action of the ST and LT enterotoxins in ETEC?
increase in cAMP and cGMP
What pathogen is responsible 30-57% of diarrhea among military personnel in African and mid east?
ETEC
ETEC (is there blood in stool)?
NO
In ETEC, immunity to endemic serotyopes leads to adult immunity T/F?
TRUE;
ETEC (intracellular or extracellular)?
Extracellular; antibody
What is the major difficulty in developing vaccine for ETEC?
variety of serotypes
This E. coli is identical to shigella disease (range of watery diarrhea to dysentery); has a lrage shigella virulence plasmid; World-wide and common in children?
EIEC (enteroinvasive)
This E.Coli is a major pathogen and cause of acute and chronic diarrhea in infants < 2 years old; and is a true age-restricted pathogen?
EPEC
T/F breast milk is protective for EPEC?
TRUE;
The gene for the bundle-forming pillus involved in the intial adherence of EPEC to Small Intestin mucosa is located where in the bacteria?
Virulence plasmid
What is the Late (intimate) adherence of EPEC mediated by, and where are these factors encoded?
Intimin; encoded on a chromosomal pathogenicity island
What are the symptoms of hemorrhagic colitis?
abd pain; NO FEVER; bloody diarrhea; VARIABLE presence of fecal PMN
microangiopathic hemolytic anemia, thrombocytopenia, glomerular thrombosis
EHEC such as E. coli 157 has attaching and effacing intestinal lesion which are encoded where in the chromosome?
Pathogenicity island
The shiga toxin produced by EHEC is bacteriophage produced T/F?
TRUE;
What is the difference between STEC and EHEC?
STEC has no intimin and no LEE (pathogenicity island); Both have bacteriophage encoded shiga toxin
What does shiga toxin bind to in glomeruli?
Gb3 receptor
What two factors increase the risk of hemolytic-uremic syndrome?
High initial WBC; Antibiotic treatment (due to phage induction)
EHEC/STEC (human specific or zoonoses)?
Zoonoses (hamburger)
EHEC/STEC (low infectious dose or high infectious dose)?
LOW
What bacteria may you get from unpasteurized apple cider and milk?
EHEC/STEC (as well as salmonella)
What type of AGAR would be useful if you wanted to grow E. COLI 157 H7?
sorbitol MacConkey (O157 does not ferment sorbitol)
BFP and virulence plasmid usefule for ID'ing what E. Coli?
EPEC
EAE probes are specific for what?
Intimin (EPEC and/or EHEC)
Does STEC have intimin?
NO
ETEC (secretory or inflammatory)?
Secretory
Attaching and Effacing Lesions in intestinal (which E. Coli)?
EPEC and EHEC
Invasion of epithelial cells, colonic ulcers, dysentery (EHEC, EPEC, EIEC, ETEC)?
EIEC
Inflammatory diarrhea, carried by new puppies, gull shaped rods?
Campylobacter jejuni
C. jejuni is microaerophilic T/F?
TRUE;
C. Jejuni (oxidase negative or positive)?
Positive
Campylobacter jejuni (human specific or zoonoses)?
Zoonoses (birds and other amimals)
What are the two major complications of campylobacter jejuni?
Guillain Barre and Reiter's Syndrome
What is the mechanism for Guillain Barre developed from campylobacter jejuni?
antibody cross reacts with peripheral nerve myelin
This syndrome complicates campylobacter jejuni and Shigella, causes a reactive arthritis, affects the urinary tract, eyes, skin and mucus membranes, and affects HLA b27 patients more?
Reiter's Syndrome
What do you need to culture campylobacter jejuni?
selective medium WITH antibiotics, 42 degree C, Increased CO2, look for oxidase +
Which vibrio cholera cause epidemic and pandemic cholera?
O1 and O139
Cholera (inflammatory or secretory diarrhea)?
Secretory (watery, vomiting, leg crasmps)
Which biotype of V. cholera is more severe (El Tor or Classical)?
Classical
What are some clinical signs of cholera gravis?
rice water stool; absent peripheral pulse; decreased BP; sunken eyes; decreased turgor; hyperventilation; muscle cramps (decreased K)
How does V cholera colonize the small intestine?
Toxin co-regulated pili (TCP)
The A subunit of cholera toxin does what?
activates adenyalte cyclase via ADP ribosylation of the GTP-binding protein
The B subunit of cholera binds to what?
GM1 ganglioside molecules
Where is the Cholera toxin encoded?
bacteriophage
Which virulence factor is most important for cholera (TCP or cholera toxin)?
cholera toxin
Cholera toxin increase Cl secretion in crypt cells T/F?
TRUE;
Cholera toxin causes decreased absorption of Cl and Na in villus cells T/F?
TRUE;
V. Cholera (low infectious dose, or high infectious dose)?
HIGH (person to person not important)
T/F seafood can transmit V. Cholera?
TRUE
T/F decreased acidity in the stomach (achloridia) will increase severity of Cholera?
TRUE;
What blood group increases the severity of cholera infection?
O
T/F V. Cholera can be transmitted through frozen fresh coconut milk?
TRUE;
What kind of AGAR should you use for V. Cholera?
TCBS (sucrose fermenting)
What kind of therapy is recommended for Cholera?
Oral rehydration salts and Ringers lactate
This bacteria produces a thermostable hemolysin (Tdh) previously called Kanagawa toxin?
V. Parahaemolyticus
Common in JAPAN, Seafood, watery diarrhea?
V. Parahaemolyticus
Raw Oysters?
V. cholera, parahaemolyticus, vulnificus
What happens to the incidence of V. parahaemolyticus as temperature increases ?
Increases; something with oysters
Exposure to contaminated sea water leading to wound infections?
V. vulnificus
What pathogen was responsible for the multistate 2008 outberak associated with jalapenos, and responsible for a huge economic blow to the tomato industry?
Salmonella enterica saint paul
This Surveillance System was establishe din 1996, estimates illness burden, and monitors trends for 10 specific pathogens, with 10 sites in the US?
US FoodNet
This surveillance network is a dynamic internet accessible pattern database and uses PGFE to detect pathogens?
PulseNet
What are the two probabale factors for the emergence of ETEC in the US population?
Increasing free trade and greater international travel
A boy comes in with generalized muscle weakness and had a reported case of acute diarrhea 8 days before onset?
Campylobacter jejuni (guillen-barre)
What are the findings on electrophysiology for guillen barre?
very low compund muscle action potentials in lower limbs with normal compound sensory nerve action potentials
What is the most common cause of acute flaccid paralysis in humans?
Guillen-Barre Syndrome
What is the most common antecedent infection of Guillen Barre?
Campylobacter jejuni
What is the cause of cross reacting antigen with GM1 antigen on Myelin from campylobacter jejuni?
Sialyltransferases which synthesize ganglioside-like epitopes
What cancer is H. pylori associated with?
Gastric adenocarcinoma
Compared to the distribution of world H. Pylori infection and Gastric Cancer, are they the same or are there differences?
Differences exist indicating a multifactorial cause of cancer
Curved, gram negative rods, microaerophilic, + urease?
Helicobacter Pylori
What does urease do for the H. Pylori?
forms a protective cloud of ammonia around the bacteria within the acidic intestinal and gastric cavity
What virulence factors do H. Pylori use for colonization?
Urease, Mucinase, Phospholipase Flagella
How does H. Pylori defend itself from phagocytes?
arginase (prevents NO synthesis); catalase; SOD
How can H. Pylori cause direct damage to tissue?
urease; and vacuolating cytotoxin
Describe the pathogenesis of H. Pylori?
Binds to gastric mucosa (with urease, mucinase, phospholipase, and flagella) > causes epithelial damage (Urease, vacuolating cytotoxin) > Chronic superficial gastritis and Chronic deep gastritis (arginase; SOD; catalase) > Early CAG > Late CAG > Gastric carcinoma
In developing countries, people are colonized at a (younger or older) age?
Younger
T/F studies have shown that once H. Pylori colonize, genetic change occurs over time?
TRUE;
T/F In H. Pylori, Co-infections have been found to be rare
TRUE;
What stain will be used to identify H. Pylori histologically?
Wurthrin-Starry stain (or Giemsa also)
What are some ways of diagnosing H. Pylori?
Breath test, stain (wurthin-starry), Urease, culture, antibody, gastroscope
What color does urea agar turn if H. Pylori is present?
Pink (from yellow)
What is the preferential treatment for H. Pylori?
metronidazole; bismuth (pepto); tetracycline
What does metranidazole do?
Bacteriocidal antibiotic affecting nucleic acid synthesis. Must be broken down into active form by oxidoreductases. Use to treat, H. Pylori.
What are the symptoms of pyelonephritis?
Flank pain, fever, nausea, vomiting, Increased C-reactive protein, Bacteremia (30%)
What are the symptoms of cystitis?
Dysuria, frequent urination, suprapubic pain
What is the most common organism in uncomplicated community aquired UTI?
Escherichia Coli
What is the most common cause of UTI in spinal cord injury patients?
Proteus Rettgeri
What do catheter placement do to the incidence of hospital-aquired Proteus Mirabalis infection?
Increases the percent
What sex is predominatly affected by UTI ?
females (males in infancy and elderly life)
Virulence factors in UPEC are found where?
on Pathogenicity Islands
This virulence factor is present in all UPEC, is important for colonization of the bladder, and causes exfoliation of the bladder cells?
Type 1 fimbria
What do the UPEC type 1 fimbria do that allow the organism to ascend from the bladder?
Phase variation
Culture of how many colonies of bacteria establishes the diagnosis of UTI?
> 100,000
This virulence factor present in UPEC adheres to digalactoside-reeptors (P blood group) and is important for colonization of the upper urinary tract?
P pili (pap pili)
Does UPEC have hemolysin?
YES
This virulence factor present in UPEC inhibits Rho GTPase and affects the actin cytoskeleton?
Cytonecrotizing factor (CNF toxin)
This cause of UTI is a member of the enterobacteriacaea and produces a "swarming motility" on solid agar?
Proteus Mirabilis
Which does proteus mirabilis prefer (upper urinary or lower urinary tract)?
Upper urinary tract
UTI is suspected and cultures are drawn. Colonies show a metallic sheen on EMB agar?
UPEC (eosin methylene blue)
What does proteus mirabalis secrete that is associated with kidney stone formation?
Urease (prescribe a urease inhibitor)
Which type of kidney stones is protease mirabalis more likely to create?
Struvite stones
How do you diagnose an uncomplicated UTI?
obtain a clean catch mid-stream sample > 100,000
How many bacteria is diagnostic in a complicated UTI?
between 100 - 10000
How many organisms are diagnostic in a suprapubic tap?
Any organisms
Which enterics produce Secretory diarrhea?
ETEC and Cholera
Which enterics produce Inflammatory diarrhea?
Shigella, Nontyphoidal Salmonella, Campylobacter, Yersinia
Which enterics cause Hemorrhagic colitis?
EHEC, STEC
Which enteric produce LT and ST?
ETEC
What kinds of colonization fimbriae does Cholera have?
toxin co-regulated pili TCP
Which enterics cause an increase in cAMP?
ETEC and Cholera
Comma shaped organisms produce watery diarrhea?
V. Cholera
Which enterics destroy M-cells as part of their pathogenesis?
Shigella
Which enterics cause enteric fever?
Salmonella Typhi, Paratyphi
Which enterics have a Vi antigen capsule?
Typhoidal Salmonella
Which enteric uses macrophages to travel throughout the body?
Typhoidal Salmonella
Which enterics cause Hemolytic Uremic Syndrome?
Shigella (if produce shiga toxin); EHEC; STEC
Which enterics produce shiga toxin?
EHEC, STEC, Shigella (few)
Kanagawa toxin, Oystres, Non-inflammatory bloody diarrhea?
Vibrio Parahaemolyticus
3 Ps of EPEC?
Protracted pediatric diarrhea; Pedestal formation (attaching and effacing lesions); Passive protection from breast milk
Two T's of ETEC?
Travers diarrhea; Two Toxins LT and ST
Which enterics are Zoonotic?
Nontyphoidal salmonella; Yersinia; Campylobacter; EHEC/STEC
Which enterics are human specific?
Shigella, typhodial salmonella, vibrio cholerae, Vibrio parahaemolyticus, ETEC, EIEC, EPEC
Whats the #1 cause of bacterial diarrhea in the US?
Salmonella (non-typhodial)
Which enterics are the big killers of the world?
Salmonella typhi, paratyphi
Which enterics do we have vaccines for?
Typhoid fever and Cholera
Which enterics cause Tan/Clear -lac response on McConkey Agar?
Shigella and Salmonella
What response does EHEC have on SORBITOL McKonkey AGAR?
TAN/CLEAR (does not ferment)
Unpasteurized juice?
Ecoli 0157
Raw Oysters?
Vibrio Parahaemolyticus
Ground Beef?
E Coli 0157
Raw Eggs?
Salmonella Enterica Non Typhi
Chicken?
Salmonella and Campylobacter
Cooked Meat (esp beef)?
Clostridium perfringens
Raw Honey?
Clostridium Botulinum
Fresh Spinach?
E. Coli 0157
Which enteics have a very low ID?
Shigella and EHEC
Apple Cider (unpasteurized)?
E. Coli 0157
What therapy is appropriate for Salmonella Typhi infection?
ciprofloxacin or ceftriaxone
Where can salmonella typhi be carried in a carrier state (like typhoid mary)?
Gallbladder
Asplenic patients have a harder time clearing infections from what general class of bacteria of which salmonella typhi belongs to?
Encapsulated
What are patients with sickle cell anemia more prone to from Salmonella Infetion?
Osteomyelitis
Which part of the GI does Salmonella colonize?
Smal intestine
This organism mimics appendicitis?
Yersinia (enterocolitic and pseudotuberculosis)
Which organism causes mesenteric lymphadenitis?
Yersinia
What enteric bacteria can survive in refrigeration, and must be screened for in blood transfusion?
Yersinia
How does cholera cause death?
Dehydration
Where is cholera toxin coded for in V. cholera?
Chromosome
Leading cause of diarrhea in japan?
V. parahaemolyticus
Complications of Campylobacter Enterocolitis?
Guillain Barre and Reiters
Bloody diarrhea, cramps, vomiting, fever, and gull shaped rods?
Campylobacter Jejuni
What is the oxygen dependance of Staphylococci?
Facultative Anaerobes
A yellow, beta-hemolyticu colony on a blood agar is suggestive for what?
S. aureus
A White, non hemolytic colony on blood agar is suggestive for what?
S. epidermis
Gram positive cocci in cluster; Catalase positve; Coagulase Postive?
S. Aureus
Gram postivei cocci in clusters; Catalase Positive; Coagulase Negative; Acid from glucose positive?
S. epidermidis
Gram postive cocci in clusters; Catalase Positive; Coagulase Negative; Acid from glucose negative?
S. Saprophyticus
What gram positive cocci are easy to distinguish by a catalase test?
Staphylococcus (positive) and Streptococcus (negative)
What are the 5 skin infections caused by Staphylococcus Aureus?
Furnuncle,impetigo, carbuncle, mastitis, cellulits (folliculitis)
What are the 2 wound infections caused by staph aureus?
community aquired and surgical
What can infection of the apocrine sweat glands with staph aureus lead to?
Hidradentis suppurtiva
What is impetigo usually due to?
group A strep (30% are due to group A strep and S. Aureus)
What are some deep lesion (metastatic infections) that can be caused by S. Aureus?
osteomyelitis, septic arthritis, meningitis, pneumonia
What are some bacteremia related diseases caused by Staph Aureus?
endocarditis, meningitis, pneumonia, pyelonephritis, septicemia, and septic shock
What is septic shock caused by in S. aureus?
Peptidoglycan
What can diabetes mellitus predispose a person through s. aureus infections?
boils, furnuncles, carbuncles, and wound infections and bacteremia
What are the risk factors for endocarditis caused by S. aureus?
heroin addiction and prosthetic heart valve
What is the #1 host defense against S. Aureus infections?
Opsonophagocytosis (granulocytopenic and C3b deficient individuals are at high risk)
What three virulence factors of S. aureus protect it from phagocytes?
protein A, catalase, leukocidin
How does protein A protect S. aureus from phagocytosis?
it bonds the Fc region of Ig's
What does techoic acid do in S. aureus?
binds fibronectin and induces shock
What does coagulase in S. aureus do?
initiates conversion of fibrinogen to fibrin
What does the virulence factor hyaluronidase do for S. aureus?
acts on hyaluronic acids in CT and facilitates dissemination through subcutaneous tissues
What are the differnet cytotoxins that S. aureus produce?
Alpha hemolysin; Beta toxin (sphingomyelinase C - kills cells by hydrolysis of membrane phospholipids); Delta toxin; Gamma toxin and Panton-Valentine Leukocidin (lysis of neutrophils and macrophages)
What toxins are produced by S. aureus which cause clinical diseases?
Exfoliatin A, B; Toxic shock syndrome toxin (TSST-1); Staphylococcus enterotoxin
What are the 5 toxin mediated diseases caused by S. Aureus?
Bullous impetigo, Scalded Skin Syndrome; Staphylococcal scarlet fever; toxic shock syndrome; food poisoning
What diseases do the exfoliatin A and B toxins secreted by S. Aureus cause?
Bullous impetigo; scalded skin syndrome; staphylococcal scarlet fever
How do Exfoliatins cause scalded skin syndrome?
Serine proteases - cause splitting of desmosomes in the stratum granulosum epidermis
What is the superantigen that is produced by S. aureus?
TSST-1 (toxic shock syndrome toxin 1)
Who are at risk for developing toxic shock syndrome?
menstruating women; women with barrier contraceptive devices; persons who have undergone nasal surgery
What are the top three lab findings in toxic shock syndrome?
elevated serum creatinine; thrombocytopenia; hypocalcemia
What are the major clinical signs and symptoms of toxic shock syndrome?
diarrhea, myalgia, vomiting, fever
What do staphylococcus enterotoxin cause?
food poisoning
Is there fever due to S. aureus enterotoxin induced diarrhea?
NO
Where are S. aureus enterotoxins coded?
many are phage-encoded
This is a gram-positive facultative anaerobe which is spore forming capable of producing diarrheal disease, emetic disease, and other opportunistic infections?
Bacillus cereus
What bacillus cereus toxin causes diarrheal disease due to increased cAMP?
Heat labile enterotoxin
What bacillus Cereus toxin causes emetic disease?
Heat stabile enterotoxin
Which B. cereus disease has a longer incubation and a longer duration (diarrheal or emetic)?
Diarrheal (caused by heat labile toxin)
Which B. cereus disease is due to ingestion of PRE-FORMED toxin?
Emetic disease (found in RICE)
Which foods would cause the diarrheal disease due to B cereus?
meat, vegetables, sauces
What is the difference between food poisoning due to S. aurues and B. cerues?
S. aureus has vomiting AND diarrhea
What kind of diarrhea is caused by B. cereus (watery, inflammatory, bloody)?
Watery
Studies show that non-carriers are inherently resisten to colonization by S. aureus T/F?
TRUE; may be due to host or bacterial factors
What are some places highly susceptible to MRSA?
outpatient clinics, sports settigns, tattoo parlors (many others)
What is bacteriophage typing useful for ?
Useful in tracking antibiotic resistance, investigating outbreaks in food poisoning
Where is the Penicilinase gene encoded for in S. aureus?
plasmid
Where is the MecA gene (responsible for methicillin resistance) encoded within the MRSA?
in the chromosome (rare transfer)
What gram positive, coagulase positive will you suspect if a patient has an infected wound and history of a dog bite?
Staph intermedius
What are the two coagulase negative Staphylococcus capable of causing disease in humans?
S. epidermidis, and S. saprophyticus
What are the infections caused by Staph epidermidis?
UTI (hospital aquired); osteomyelitis; endocarditis; bacteremia (immunosuppresed); endophtalmitis (ocular surgery); indwelling foreign devices
What protects Staphylococcus epidermidis from antibiotics when found on indwelling medical devices?
Biofilms
What is the 2nd most common cause of community-aquired UTI?
Staphylococcus saprophyticus
What does staphylococcus saprophyticus make that can increase the pH of urine?
urease
What is the benefit of coagulase for S. aureus?
forms a fibrin formation around the bacteria protecting it from phagocytosis
Staphylokinase is secreted from S. aureus to do what?
lyses fibrin clots (used to penetrate)
A patient has comes in with severe hypotension, rash, hx of vomiting and diarrhea and her hands and soles appear to be sloughing off. She is currently menstruating?
Toxic Shock Syndrome
Sexy staff often make people excited directly?
septic arthritis; skin infections; osteomyelitis; meningtis; pneumonia; endocarditis; DIRECT ORGAN INVOLEMENT
What is impetigo?
A contagious disease often in the face; vesicles led to pustules which crust over to become honey-colored, wet and flaky
What is currently being used to treat MRSA although resitance to it is slowly occuring?
Vancomycin
What gives S. epidermidis the ability to stick to medical devices?
Polysaccharide capsule (extracellular polymers)
Pyogenic cocci are (obligate intracellular, obligate extracellular, facultative intracellular) organisms?
Obligate extracellular (staph and strep cannot live in PMNs)
What are cocci pairs (lancet shaped) typical of?
Strep pneumo
Streptococci are catalase (positive or negative)?
Negative (distinguishes them from Staph)
What does staph aureus look like on blood agar?
Yellow ("gold"); with a clear zone around them (B-hemolytic)
Are polysaccharide antigens t-dependent or t-independent responses? What antibody is formed?
T-independent; Form IgM antibody
Can infants form an immune response to polysaccharide antigens (like those given in older Strep Pneumo vaccines)?
NO - cannot form T-independent immune response (need conjugate vaccines)
Streptococci pneumo is (non-hemolytic, Beta-hemolytic, Alpha hemolytic)?
Alpha hemolytic
What color will strep pneumo display if grown on blood agar? What causes this color?
Are very mucoid looking (glistening, goopy) and around the colonies look Green due to breakdown of hemoglobin by pneumolysin
What causes certain strains of bacteria which look glistening and goopy on agar?
polysaccharide (encapsulated organisms)
Streptoccoci pneumo is Bile (soluble or insoluble)?
Soluble (autolytic enzymes elicited when bile is added)
What other autolytic enzyme inducing compound (aside from bile) will result in lysis of a colony in streptococci pneumo?
Optochin
What are the different ways to detect polysaccharide capsules?
Quellung reaction; latex agglutination; co-agglutination
What is co-agglutination?
Killed staph aureas uses it's protein A to bind antibodies of polysaccharides
What are the surface adhesins for streptococcus pneumoniae?
PspA and Choline-binding proteins
What is a major viral predisposing factor for Streptococci pneumonia infection?
Influenza infection
What are the clinical manifestations of Pneumococcal pneumonia?
Usually Lobar; sudden onset chills, fever, pleuritic pain, rusty collered sputum (always take blood cultures)
What are some other Streptococcus pneumonia infections of the upper respiratory tract (aside pneumonia)?
otitis media, mastoditis, sinusitis
What are some extrapulmonary infections caused by S. pneumo (aside upper respiratory infections)?
meningitis (especially due to skull fracture); septic arthritis; endocarditis
What do you treat acute otitis media caused by S. pneumonia?
amoxicillin
What do you treat sinusitis caused by S. pneumonia in children and adults?
amoxicillin (both); quinolones (adults)
What do you treat pneumococcal pneumonia?
third generation cephalosporins
What do you treat meningitis caused by S. pneumo?
vancomycin plus B-lactam
What vaccine is currently recommended for children to prevent S. pneumo?
PCV13 - conjugated polysaccharides with 13 serotypes
What vaccine is recommended for adults , chronic and immunosuppresed patients (asthma and smokers) to prevent S. pneumo?
23PS - non-conjugated vaccine (all polyvalent polysacharride with 23 serotypes)
What is group A strep also commonly called?
Streptococci pyogenes
This carbohydrate antigen is part of the cell wall of Strep pyogenes and often used in rapid detection tests?
Lancefield group A antigen
Group A strep is (alpha-hemolytic, beta-hemolytic, non-hemolytic)?
B-hemolytic (just like S. aureus)
Is group A strep sensitive to bacitracim?
Yes
Group A strep is catalase (negative/positve)?
Negative
Group A strep is PYR (positive or negative)?
Positive (pyrrolidonyl arylamidase)
Can vaccines against the capsule of Group A strep be made?
No; capsule has hyaluanic acids and thus it would react with human cells as well
What is the major virulence factor of strep pyogenes?
M protein (binds to epidermis; anti-phagocytic)
Why don't we use protein M to make a vaccine against strep pyogenes?
sequence homolgy between mammalian proteins (anti self)
What are some toxin mediated responses that S. pyogenes is capable of?
scarlet fever and toxic-shock like syndrome (due to exotoxins)
What are some extracellular virulence factors made by group A strep?
Pyrogenic exotoxins (superantigens); Streptolysin O; DNAase; Streptokinase; C5a peptidase
What does streptolysin O do and how is it clinically significant?
(produced by S. pyogenes); lyses red blood cells; antigenic (antibodies in throat infections made can be detected by anti-streptolysin ASO test
This virulence factor is made by group A strep and is used by surgeons during enzymatic debridement?
Streptokinase
What are the two general classes of diseases caused by group A strep?
suppurative vs non-suppurative
What are the 2 non-suppurative diseases caused by group A strep?
Rheumatic fever and Acute glomerulonephritis
What is a way to detect wether or not a person had a strep A infection who now presents with rheumatic fever /glomerulonephritis?
Antibody titer to Streptolysin O or DNAases
What does the throat look like in Streptococcal pharyngitis?
inflamamtion with petechia or small red spots on the soft palate
Strawberry tongue, circumoral pallor, desquamation. What bacteria cause the symptoms due to a toxin?
Streptococal pyogenes (group A strep)
What do you use to treat streptococcal pharyngitis?
penicillin
What type of pyodermas can S. pyogenes produce?
impetigo, erysipelas, cellulitis, and necrotizing fasciitis
What is the differnce between toxic shock caused by Staph and Strep A?
Strep A and toxin are in the blood (bacterimia) vs Staph where the bug is localized and making the toxin. (also necrotizing fasciitis present with group A strep)
What must patients with rheumatic fever be placed on for the rest of their lives?
penicillin (prevent further antibody response to protein M and acute heart damage)
What neurological abnormalities, which is abrupt in onset, and episodic, is associated with group A strep infection?
PANDAS syndrome (pediatric autoimmune neuropsychiatric disorder associated with group A strep)
What treatment is given for group A strep infecitons?
Penicillin G
What is the current most common cause of neonatal meningitis?
Group B strep infections
Group B strep is catalase (positive or negative)?
Negative
Group B strep is (alpha hemolytic; B hemolytic; non-hemolytic)?
Beta hemolytic
Group B strep is bacitracin (insensitive or sensitive)?
Insensitive
Group B strep will test positive or negative for CAMP?
Positive (extracellular protein produced by group B that will react with a B lysin of S. aureus)
What is the treatment for group B strep?
Penicillin G and aminoglycoside
What is given to a pregnant women with a history of a baby born with group B strep?
Penicillin G
A baby is born with meningitis and you as a physician would like to rule out group A strep (you think its group B strep)? What test could you give?
Bacitracin (group B will culture and grow because its resistant); CAMP (Broup B will be positive)
This organism is part of the normal flora of the gut, and a leading cause of hospital aquired secondary infection (due to catheters, etc)?
Enterococci (facalis and faecium)
enterococci are (beta hemolytic; alpha hemolytic; non-hemolytic)?
Alpha and NON (rarely beta)
Enterococci are catalase (negative or positive)?
Negative (all strep)
What Streptococci is th eonly one to be able to survive Bile and Sodium chloride?
Enterococci
Enterococci are PYR (negative/positive)?
Positive
These two streptococci produce PYR. What is a lab test to separate the two?
Enterococci and group A strep; (either Bile or hemolysis - group A is B hemolytic and degrades on bile)
What clinical syndromes are caused by enterococci?
UTI, bacteremia, subacute endocarditis, and Wound and tissue infections
Viridans streptococci is (alpha hemolytic, beta hemolytic, non-hemolytic)?
Alpha
Viridans streptococci is optochin (sensitive, resistant)?
Resistant
Viridan streptococci is bile (sensitive, resistant)?
resistant
Viridans streptococci is PYR (positive/negative)?
Negative
What gram positive, catalase negative, alpha hemolytic organism is responsible for dentists to ask if you had previous heart disease, which, if you had a damaged heart valve would predispose you to one of the effects of this organism?
Viridans streptococci
Which is part of the normal flora of the skin and nares (S. aureus, S. pyogenes, Both)?
S. Aureus
Which causes Bullous impetigo (S. aureus, S. Pyogenes, Both)?
S. Aurues
Which one causes food poisoning (S. aureus, S. pyogenes, Both)?
S. aureus
Which one causes pharyngitis (S. aureus, S. pyogenes, Both)?
S. pyogenes
Which one causes necrotizing fascitis (S. aurues, S. pyogenes, Both)?
S. pyogenes
Which one is B hemolytic (S. aureus, S. pyogenes, Both)?
BOTH
Which one is catalase negative (S. aureus, S. pyogenes, both)?
S. pyogenes
Which one is a pus former (S. aureus, S. pyogenes, Both)?
BOTH
Which one causes Impetigo (S. aureus, S. pyogenes, BOTH)?
BOTH (S. aureus causes Bullous impetigo)
Which one causes toxic shock syndrome and associated bacteremia (S. aureus, S. pyogenes, BOTH)?
S. pyogenes (S. aureus is localized and secreting the toxin)
What are the characteristics of a strict anaerobe?
Can't use O2; can't breakdown H2O2 (no catalase); In presence of O2 superoxide accumulates (no SOD)
Clostridia can cause these diseases?
butulism, tetanus, gas gangrene, food poisoning, Clostridum difficile associated disease, pseudomembranous collitus (Because the gas fucks clostridium plenty)
Which two gram positive rods make spores?
Baccili and Clostridium
What is it called when a spore turns into a rod?
germination
What are the three kinds of botulism infections in the US?
food poisoning, wound botulism, infant botulism (floppy baby syndrome)
What causes botulism food poisoning (Bacteria, toxin)?
Toxin made in the food (spore are in the food, they germinate and produce the toxin)
What kind of paralysis is botulism?
descending flaccid paralysis (vs guillain Barre which is an ascending paralysis)
Can antibodies made against one type of botulism toxin react with those of another ?
No
What are the three most common types of botulism toxin?
A, B, E (Use another for weopanization)
Can heating destroy botulism toxin?
YES (100c for 10 mins)
What is the mechanism of action of Botilinum toxin?
prevents release of acetylcholine from neuromuscular junctions (flaccid paralysis)
What is the enzymatic activity of botulism that prevents acetylcholine release?
zinc-dependent endoprotease (cleaves a protein needed for acetylcholine release)
What are the best conditions for botulism toxin in food poisoning?
canned foods (anerobic, increased pH)
What are the clinical presentations of botulism?
dry mouth, difficulty swallowing, visual disturbances, descending paralysis; BUT NO confusion (not stroke); NO fever or GI (unless type E)
What do people with botulism often die from?
respiratory paralysis/ cardiac arrest
Why don't patients who survive botulism toxin develop antitoxin?
too little toxin in the blood for adequate immune response
What population is at risk for botulism via wound infection?
heroin users
What is the postulated pathogenesis for infant botulism?
environmental source (honey in milk) is infected with spores; SPORES germinate in BABY (CANNOT germinate in ADULT); rods make toxin
How is botulism diagnosed in the laboratory?
isolation of patient's serum/stool/food and injection of MICE with it; Once mice become ill varying antibodies to the 7 types are used to figure out which type it is
How do you treat botulism ?
trivalent antitoxin (prepared in horses)
What do we treat floppy baby syndrome?
botulism immune globin IV (prepared from adult immunization with toxoid) - - very expensive
How many antigenic types are there for C. tetani toxin?
One type (allows successful vaccination)
What is the mode of action of C. tetani toxin?
Cleaves VAMP (synaptobrevin) and prevents the release of glycine from inhibitory interneurons > Stimulations > spasms
What is the protein that is cleaved by tetanus?
VAMP or synaptobrevin
Where in the world is tetanus commonly found?
developing countries; In US from older adults who aren't immunized
What are the clinical presentations of tetanus?
lockjaw; risus sardonicus (characteristic facial expression); stiff neck, difficulty swallowing, rigid abdomen, spasms DEATH by respiratory
What do you do after someone recovers from tetanus?
immunize
Is antitoxin to tetanus effective once the toxin has bound ?
NO
What antibiotic would you give to a patient if you think that C. tetani is still there?
metronidazole
T/F infections by anaerobes are normally not mixed (no other bacteria will be found)?
FALSE; normally other anaerobes are present
Which clostridium is the most common cause of invasive clostridial infections?
C. perfringens
What does C. Perfringens produce that is capable of in vivo lysis of cells?
Alpha Toxin (lecithinase)
What can alpha toxin (C. Perfringen) lyse in vivo?
red blood cells; platelets; endothelial cells and leukocytes
What is a diagnostic test for Clostridium Perfringens?
place it in milk; look for "stormy fermentation"
Describe what happens to a person if they ingest cooked beef which has had C. perfringens spores in them?
Ingest RODS (which replicated in the beef)> rods sporulate in the intestine > during sporulation enterotoxin is produced > diarrhea (self-limiting
What is the most frequently identified cause of nosicomial diarrhea?
Clostridium Difficile
What is the relationship between C. Difficle and antibiotic use in the hospital?
antibiotics kill off normal flora and allow difficile to outgrow (antibiotic resistant)
What do the C. difficile toxins (enterotoxin and cytotoxin) do?
add a glucos to the RhoA of cell's cytoskeletons and cause the cells to "round up"
What is the range of symptoms of C.Difficile associated diseases?
mild diarrhea to pseudomembranous colitis
What part of the GI is C. Difficile a problem ?
Large Intestine (antibiotics destroy normal flora)
A patient has been in the hospital for a while, has diarrhea, and has been on antibiotics?
C. Difficile
What are some ways C. Difficile can be diagnosed?
ELISA, culture, sigmoidoscope
What gram negative anaerobe are associated in mixed infections, present in the colon, usually infect after surgical procedures?
Bacteriodes Fragilis
Do bacteriodes fragilis have a capsule?
YES (they are fragile )
Can penicillin be used to cure bacteroides fragilis infection?
NO - B lactamase
Where can bacteroides fragilis grow which protects them and allows for detection in the lab?
Bile
Are deep infections due to anaerobes from exogenous or endogenous sources?
Mostly endogenous (our own)
How do facultative anaerobes help anaerobes live?
They partner up and lower the O2 tension in injured tissue sites
What is synergism?
one organism producing materials that facilitate the growth of another, or its protection (anaerobes producing penicillinases to protect group a strep in tonsillitis)
T/F For the most part, anaerobic infections are mixed and rarely due to a single species?
TRUE;
What do anaerobes NEED in order to facilitate spread in tissue and growth?
"injury" - compromised oxygen supply, trauma, tissue destruction, and antecedent infections with aerobes (lower the O2)
What are some unique clinical characteristics of anearobes?
crepitation (gas former, bad odors, brownish serous fluid); Abscess formation
Where in our bodies are most of the endogenous anaerobes located?
internal mucous membranes
What are anaerobic infections above the waste normally due to ?
dentition
What are babies more prone to once they develop teeth?
anaerobic infections
What is a very common oral gram negative rod anaerobe?
prevotella (B lactamase)
What is the peak age of periodontal disease?
20-35
What antibiotics can be used for above the waist anaerobes?
all - mostly use penicillin/clindamycin
What part of the GI has the most anaerobes?
Colon
What are the antibiotics used for anaerobe infections?
penicillins, carbapenems, clindamycin, metronidazole, cephalosporins (cephamycins), vancomycin, quinolones
What can surgeons do to cure anaerobic infections?
remove devitalized tissue, expose to good oxygen
A patient was treated with both ceftriaxone and clindamycin, which one was used for anaerobic infections?
clindamycin
What antibiotic would be used for a anaerobe in the CNS (need good penetration)?
metronidazole
What anaerobe stains to show sulfur filamentous rods?
actinomyces (dental)
What antibiotic was used in the case of actinomyces infection as well as to cover for gram negative rods?
Unasyn (ampicillin and B-lactamase inhibitor - sulbactam)
What is the natural reservoir for actinomyces?
humans
"lumpy wooden jaw"
actinomyces infection
What is the treatment for actinomyces infection ?
long term high dose penicillin
T/F E. Coli ferments lactose?
TRUE;
These E. Coli are responsible for travelers diarrhea and children's diarrhea?
ETEC
This E.coli shows bacillary dysentary similar to shigella?
EIEC
This E. Coli shows infant diarrhea?
EPEC; also EAEC
This E. Coli produce shiga toxin and displays hemorrhagic colitis and Hemolytic Uremic Syndrome?
EHEC/STEC
What are the steps of pathogenesis for ETEC?
ingestion (food/water - human feces) > colonization small intestine (colinization fimbria CFA and CS) > elaboration of enterotoxins (ST and LT)
ETEC (watery diarrhea or inflammatory diarrhea)?
Watery
CF, LT and ST genes (virulence factors) are encoded where in ETEC?
Large plasmids
What is the mechanism of action of the ST and LT enterotoxins in ETEC?
increase in cAMP and cGMP
What pathogen is responsible 30-57% of diarrhea among military personnel in African and mid east?
ETEC
ETEC (is there blood in stool)?
NO
In ETEC, immunity to endemic serotyopes leads to adult immunity T/F?
TRUE;
ETEC (intracellular or extracellular)?
Extracellular; antibody
What is the major difficulty in developing vaccine for ETEC?
variety of serotypes
This E. coli is identical to shigella disease (range of watery diarrhea to dysentery); has a lrage shigella virulence plasmid; World-wide and common in children?
EIEC (enteroinvasive)
This E.Coli is a major pathogen and cause of acute and chronic diarrhea in infants < 2 years old; and is a true age-restricted pathogen?
EPEC
T/F breast milk is protective for EPEC?
TRUE;
The gene for the bundle-forming pillus involved in the intial adherence of EPEC to Small Intestin mucosa is located where in the bacteria?
Virulence plasmid
What is the Late (intimate) adherence of EPEC mediated by, and where are these factors encoded?
Intimin; encoded on a chromosomal pathogenicity island
What are the symptoms of hemorrhagic colitis?
abd pain; NO FEVER; bloody diarrhea; VARIABLE presence of fecal PMN
microangiopathic hemolytic anemia, thrombocytopenia, glomerular thrombosis
EHEC such as E. coli 157 has attaching and effacing intestinal lesion which are encoded where in the chromosome?
Pathogenicity island
The shiga toxin produced by EHEC is bacteriophage produced T/F?
TRUE;
What is the difference between STEC and EHEC?
STEC has no intimin and no LEE (pathogenicity island); Both have bacteriophage encoded shiga toxin
What does shiga toxin bind to in glomeruli?
Gb3 receptor
What two factors increase the risk of hemolytic-uremic syndrome?
High initial WBC; Antibiotic treatment (due to phage induction)
EHEC/STEC (human specific or zoonoses)?
Zoonoses (hamburger)
EHEC/STEC (low infectious dose or high infectious dose)?
LOW
What bacteria may you get from unpasteurized apple cider and milk?
EHEC/STEC (as well as salmonella)
What type of AGAR would be useful if you wanted to grow E. COLI 157 H7?
sorbitol MacConkey (O157 does not ferment sorbitol)
BFP and virulence plasmid usefule for ID'ing what E. Coli?
EPEC
EAE probes are specific for what?
Intimin (EPEC and/or EHEC)
Does STEC have intimin?
NO
ETEC (secretory or inflammatory)?
Secretory
Attaching and Effacing Lesions in intestinal (which E. Coli)?
EPEC and EHEC
Invasion of epithelial cells, colonic ulcers, dysentery (EHEC, EPEC, EIEC, ETEC)?
EIEC
Inflammatory diarrhea, carried by new puppies, gull shaped rods?
Campylobacter jejuni
C. jejuni is microaerophilic T/F?
TRUE;
C. Jejuni (oxidase negative or positive)?
Positive
Campylobacter jejuni (human specific or zoonoses)?
Zoonoses (birds and other amimals)
What are the two major complications of campylobacter jejuni?
Guillain Barre and Reiter's Syndrome
What is the mechanism for Guillain Barre developed from campylobacter jejuni?
antibody cross reacts with peripheral nerve myelin
This syndrome complicates campylobacter jejuni and Shigella, causes a reactive arthritis, affects the urinary tract, eyes, skin and mucus membranes, and affects HLA b27 patients more?
Reiter's Syndrome
What do you need to culture campylobacter jejuni?
selective medium WITH antibiotics, 42 degree C, Increased CO2, look for oxidase +
Which vibrio cholera cause epidemic and pandemic cholera?
O1 and O139
Cholera (inflammatory or secretory diarrhea)?
Secretory (watery, vomiting, leg crasmps)
Which biotype of V. cholera is more severe (El Tor or Classical)?
Classical
What are some clinical signs of cholera gravis?
rice water stool; absent peripheral pulse; decreased BP; sunken eyes; decreased turgor; hyperventilation; muscle cramps (decreased K)
How does V cholera colonize the small intestine?
Toxin co-regulated pili (TCP)
The A subunit of cholera toxin does what?
activates adenyalte cyclase via ADP ribosylation of the GTP-binding protein
The B subunit of cholera binds to what?
GM1 ganglioside molecules
Where is the Cholera toxin encoded?
bacteriophage
Which virulence factor is most important for cholera (TCP or cholera toxin)?
cholera toxin
Cholera toxin increase Cl secretion in crypt cells T/F?
TRUE;
Cholera toxin causes decreased absorption of Cl and Na in villus cells T/F?
TRUE;
V. Cholera (low infectious dose, or high infectious dose)?
HIGH (person to person not important)
T/F seafood can transmit V. Cholera?
TRUE
T/F decreased acidity in the stomach (achloridia) will increase severity of Cholera?
TRUE;
What blood group increases the severity of cholera infection?
O
T/F V. Cholera can be transmitted through frozen fresh coconut milk?
TRUE;
What kind of AGAR should you use for V. Cholera?
TCBS (sucrose fermenting)
What kind of therapy is recommended for Cholera?
Oral rehydration salts and Ringers lactate
This bacteria produces a thermostable hemolysin (Tdh) previously called Kanagawa toxin?
V. Parahaemolyticus
Common in JAPAN, Seafood, watery diarrhea?
V. Parahaemolyticus
Raw Oysters?
V. cholera, parahaemolyticus, vulnificus
What happens to the incidence of V. parahaemolyticus as temperature increases ?
Increases; something with oysters
Exposure to contaminated sea water leading to wound infections?
V. vulnificus
What pathogen was responsible for the multistate 2008 outberak associated with jalapenos, and responsible for a huge economic blow to the tomato industry?
Salmonella enterica saint paul
This Surveillance System was establishe din 1996, estimates illness burden, and monitors trends for 10 specific pathogens, with 10 sites in the US?
US FoodNet
This surveillance network is a dynamic internet accessible pattern database and uses PGFE to detect pathogens?
PulseNet
What are the two probabale factors for the emergence of ETEC in the US population?
Increasing free trade and greater international travel
A boy comes in with generalized muscle weakness and had a reported case of acute diarrhea 8 days before onset?
Campylobacter jejuni (guillen-barre)
What are the findings on electrophysiology for guillen barre?
very low compund muscle action potentials in lower limbs with normal compound sensory nerve action potentials
What is the most common cause of acute flaccid paralysis in humans?
Guillen-Barre Syndrome
What is the most common antecedent infection of Guillen Barre?
Campylobacter jejuni
What is the cause of cross reacting antigen with GM1 antigen on Myelin from campylobacter jejuni?
Sialyltransferases which synthesize ganglioside-like epitopes
What cancer is H. pylori associated with?
Gastric adenocarcinoma
Compared to the distribution of world H. Pylori infection and Gastric Cancer, are they the same or are there differences?
Differences exist indicating a multifactorial cause of cancer
Curved, gram negative rods, microaerophilic, + urease?
Helicobacter Pylori
What does urease do for the H. Pylori?
forms a protective cloud of ammonia around the bacteria within the acidic intestinal and gastric cavity
What virulence factors do H. Pylori use for colonization?
Urease, Mucinase, Phospholipase Flagella
How does H. Pylori defend itself from phagocytes?
arginase (prevents NO synthesis); catalase; SOD
How can H. Pylori cause direct damage to tissue?
urease; and vacuolating cytotoxin
Describe the pathogenesis of H. Pylori?
Binds to gastric mucosa (with urease, mucinase, phospholipase, and flagella) > causes epithelial damage (Urease, vacuolating cytotoxin) > Chronic superficial gastritis and Chronic deep gastritis (arginase; SOD; catalase) > Early CAG > Late CAG > Gastric carcinoma
In developing countries, people are colonized at a (younger or older) age?
Younger
T/F studies have shown that once H. Pylori colonize, genetic change occurs over time?
TRUE;
T/F In H. Pylori, Co-infections have been found to be rare
TRUE;
What stain will be used to identify H. Pylori histologically?
Wurthrin-Starry stain (or Giemsa also)
What are some ways of diagnosing H. Pylori?
Breath test, stain (wurthin-starry), Urease, culture, antibody, gastroscope
What color does urea agar turn if H. Pylori is present?
Pink (from yellow)
What is the preferential treatment for H. Pylori?
metronidazole; bismuth (pepto); tetracycline
What does metranidazole do?
Bacteriocidal antibiotic affecting nucleic acid synthesis. Must be broken down into active form by oxidoreductases. Use to treat, H. Pylori.
What are the symptoms of pyelonephritis?
Flank pain, fever, nausea, vomiting, Increased C-reactive protein, Bacteremia (30%)
What are the symptoms of cystitis?
Dysuria, frequent urination, suprapubic pain
What is the most common organism in uncomplicated community aquired UTI?
Escherichia Coli
What is the most common cause of UTI in spinal cord injury patients?
Proteus Rettgeri
What do catheter placement do to the incidence of hospital-aquired Proteus Mirabalis infection?
Increases the percent
What sex is predominatly affected by UTI ?
females (males in infancy and elderly life)
Virulence factors in UPEC are found where?
on Pathogenicity Islands
This virulence factor is present in all UPEC, is important for colonization of the bladder, and causes exfoliation of the bladder cells?
Type 1 fimbria
What do the UPEC type 1 fimbria do that allow the organism to ascend from the bladder?
Phase variation
Culture of how many colonies of bacteria establishes the diagnosis of UTI?
> 100,000
This virulence factor present in UPEC adheres to digalactoside-reeptors (P blood group) and is important for colonization of the upper urinary tract?
P pili (pap pili)
Does UPEC have hemolysin?
YES
This virulence factor present in UPEC inhibits Rho GTPase and affects the actin cytoskeleton?
Cytonecrotizing factor (CNF toxin)
This cause of UTI is a member of the enterobacteriacaea and produces a "swarming motility" on solid agar?
Proteus Mirabilis
Which does proteus mirabilis prefer (upper urinary or lower urinary tract)?
Upper urinary tract
UTI is suspected and cultures are drawn. Colonies show a metallic sheen on EMB agar?
UPEC (eosin methylene blue)
What does proteus mirabalis secrete that is associated with kidney stone formation?
Urease (prescribe a urease inhibitor)
Which type of kidney stones is protease mirabalis more likely to create?
Struvite stones
How do you diagnose an uncomplicated UTI?
obtain a clean catch mid-stream sample > 100,000
How many bacteria is diagnostic in a complicated UTI?
between 100 - 10000
How many organisms are diagnostic in a suprapubic tap?
Any organisms