Term
Bacterial requirements for growth in the human host. |
|
Definition
nutrients, optimal temperature (mesophiles), optimal pH, presence or absence of oxygen |
|
|
Term
oxygen is required and are inhibited by absence of oxygen (cannot ferment)= |
|
Definition
obligate or strict aerobes |
|
|
Term
What are examples of obligate or strict aerobes? |
|
Definition
legionella, pseudomonas aeruginosa, mycobacterium, bordetella pertussis |
|
|
Term
organisms cannot grow in the presence of oxygen (ferment)= |
|
Definition
|
|
Term
What are examples of obligate anaerobes? |
|
Definition
clostridium spp, bacterioides, peptostreptococcus |
|
|
Term
Organisms able to grow in the presence/absence of oxygen? |
|
Definition
|
|
Term
Examples of facultative anaerobes? |
|
Definition
staphylococcus spp, enterococci, E coli, listeria, yeasts, WBCs |
|
|
Term
Microaerophils require oxygen at levels reduced to ___% of normal. |
|
Definition
|
|
Term
In addition to requiring reduced oxygen levels, many microaerophils also require... |
|
Definition
increased CO2 (they are capnophiles) |
|
|
Term
Examples of microaerophils. |
|
Definition
neisseria spp., haemophilus spp, S. pyogenes, campylobacter jejuni, helicobacter pylori, borrelia bergdorferi |
|
|
Term
Examples of aerotolerant anaerobes. |
|
Definition
clostridium perfringens, treponema pallidum |
|
|
Term
Where in a test tube are facultative anaerobic bacteria found? |
|
Definition
most at the top but can be found throughout |
|
|
Term
Where are microaerophiles found in a test tube? |
|
Definition
gather at the upper part of the test tube but not the very top |
|
|
Term
How do you grow microaerophiles? |
|
Definition
|
|
Term
Two basic groups of anaerobic bacteria: |
|
Definition
endogenous anaerobes-normal or transient flora, opportunistic pathogens exogenous anaerobes- spore formers, disease caused by vegetative form |
|
|
Term
Where in the body do endogenous anaerobic bacteria NORMALLy inhabit? |
|
Definition
oxygen deficient area of body created by presence of facultative aerobic organisms (synergism) |
|
|
Term
What allows an endogenous anaerobe to become pathogenic? |
|
Definition
tissue injury causes anoxia; indiscriminate use of broad spectrum antibiotics make conditions favorable to growth of anaerobes |
|
|
Term
Name endogenous anaerobic bacteria that are gram positive cocci. |
|
Definition
peptostreptococcus, gemella |
|
|
Term
Name the endogenous anaerobic bacteria that are gram positive bacilli. |
|
Definition
actinomyces, propionibacterium, mobiluncus, lactobacillis, eubacterium, bifodobacterium |
|
|
Term
What are the endogenous anaerobic bacteria that are gram negative bacilli? |
|
Definition
bacteriodes, fusobacterium, porphyromonas, veilonella, prevotella |
|
|
Term
Most common infections for anaerobic bacteria. |
|
Definition
oral, dental, pleuropulmonary, intraabdominal, female genital tract, skin, periodontal disease, soft tissue, and bone infections |
|
|
Term
What pathogenic molecule do all anaerobes possess? |
|
Definition
enzymes (collagenase, neuraminidase, deoxyribonuclease, deoxyribonuclease [DNase], heparinase, and protease), that may play a role in pathogenesis by helping the organisms to penetrate tissues and to set up infection after surgery or other trauma |
|
|
Term
The three most common disease causing anaerobes. |
|
Definition
bacteriodes, prevotella, fusobacterium together constitute 1/3 of all clinical isolates |
|
|
Term
Light microscopy of bacterioides= |
|
Definition
most strains are encapsulated. Vaculoization or irregular staining common, particularly in broth media. Some pleomorphism may also be seen. gram-negative |
|
|
Term
90% of bacteriodes infections are located where? |
|
Definition
|
|
Term
Does bacteroides use oxygen? |
|
Definition
anaerobic but they are aerotolerent and thus can survive in the abdominal cavity |
|
|
Term
How does B fragilis become invasive? |
|
Definition
not overtly invasive, can cause intraabdominal infections when the mucosal wall of the intestine is disrupted. Like during GI surgery, perforated or gangrenous appendicitis, perforated ulcer, diverticulitis, trauma, and inflammatory bowel disease |
|
|
Term
Which antibiotics are bacteroides resistant to? |
|
Definition
beta lactams, aminoglycosides, and recently many have acquired resistance to erythromycin and tetracycline |
|
|
Term
Why is bacteroides antibiotic resistance a concern? |
|
Definition
bacteroides may become a reservoir for resistance in other, more highly pathogenic bacterial strains |
|
|
Term
Benefits of having bacteroides. |
|
Definition
1)anaerobic production of butyrate, acetate and proprionate provides 70% of energy supply of colonic enterocytes. 2) enterohepatic bile acid recirculation and bile acid biotransformation. 3) competes with pathogenic bacteria (via deconjugating bile salts and changing the pH) 4) produces some vitamin K (menaquione, vitamin K2) |
|
|
Term
Describe fusobacterium respiration, whether they form spores, shape, and gram stain. |
|
Definition
anaerobic, non spore forming, filamentous and gram negative bacillus |
|
|
Term
Is Fusobacterium normal flora? |
|
Definition
yes, of mucosal surfaces of mouth, URT, GI tract and vagina. |
|
|
Term
Which organism is the bridging organism in dental plaque? |
|
Definition
|
|
Term
What diseases are associated with fusobacterium? |
|
Definition
F. nucleatum= periodontal diseases F. necrophorum= Lemierre's syndrome F. ulcerans= topical skin ulcer from animal/insect bite |
|
|
Term
Throat diseases caused by fusobacterium necrophorum. |
|
Definition
10% of all acute sore throats, 21% of re-occurring sore throats, 23% of peritonsillar abscesses |
|
|
Term
What is Lemierre's syndrome? |
|
Definition
a form of thrombophelbitis caused by fusobacterium necrophorum that usually affects young healthy adults. "a forgotten disease" |
|
|
Term
What is the mortality rate of Lemierre's syndrome? |
|
Definition
90% before antibiotics, 5% with antibiotics |
|
|
Term
What is the pathogenesis of lemierre's syndrome? |
|
Definition
after S. pyogenes infection causes peritonsillar abscess, abscess is infected with F. necrophorum which then migrates to the jugular vein and forms an infected clot. Thrombi can break off and become embedded in the lungs as an emboli, causing shortness of breath, chest pain and severe pneumonia, or may travel to the brain and joints |
|
|
Term
What antibiotics are used to treat F. necrophorum? |
|
Definition
susceptible to beta-lactams, metronidazole, clindamycin and third generation cephalosporins. polymicroby usually exists so need more than one drug |
|
|
Term
What is the disease caused by actinomyces bacteria? |
|
Definition
actinomycosis which is characterized by the development of chronic granulomatous lesions that become suppurative and form abscesses connected by sinus tracts. |
|
|
Term
What is the presence of a actinomyces colony? |
|
Definition
yellow or orange due to the presence of sulfur granules |
|
|
Term
How is actinomyces transmitted? |
|
Definition
from the soil or water; there is no person-person transmission. Also from colonized foreign bodies such as intrauterine devices |
|
|
Term
What organ systems can get actinomycosis and how? |
|
Definition
cerviofacial (poor oral hygeine or dental trauma), thoracic actinomycosis, abdominal actinomycosis (GI surgery_, pelvic actinomycosis (infected intrauterine device), central nervous actinomycosis (spread from the lungs) |
|
|
Term
What is the unique metabolism of proprionibacterium? |
|
Definition
able to synthesize propionic acid by using unusual transcarboxylase enzymes |
|
|
Term
Does propionibacterium cause disease? |
|
Definition
primarily facultative parasites and commensals that live in and around the sweat and sebaceous glands. Ubiquitous and do not cause problems for most but can cause acne and other skin conditions as well as shunt infections |
|
|
Term
T/F THe main etiologic agent of periodontal disease are aerobes. |
|
Definition
|
|
Term
What is the ecological plaque hypothesis? |
|
Definition
natural plaque--> inflammation and increased gingival cervicular fluid flow --> utilized by Gram (-) anaerobes--> suppress growht of normal sepcies with shift to periodontopathic anaerobic flora (PAF) --> PAFs secrete proteases lipase, etc. that produce episodic tissue destruction--> periodontitis and gingivitis |
|
|
Term
|
Definition
mainly gram (+) cocci with few spirochetes or motile rodes |
|
|
Term
Bacteria in a mouth with chronic marginal gingivitis= |
|
Definition
about 55% of cells are gram positive with occasional spirochetes and motile rodes |
|
|
Term
Dental flora in a mouth with chronic periodontitis= |
|
Definition
about 75% of cells are gram-negative (90% being strict anaerobes). Motile rods and spirochetes are prominent |
|
|
Term
What is the bacteiral flora in a mouth with aggressive periodontitis |
|
Definition
about 65-75% are gram negative bacilli. Few spirochaetes or motile rods present |
|
|
Term
Three bacteria that cause dentoalveolar infections? |
|
Definition
prevotella, porphyromonas, fusobacterium |
|
|
Term
What are two ways endogenous anaerobes can become opportunistic pathogens with the environment becomes "less aerobic"? |
|
Definition
lowering environmental redox potential by either facultative anaerobes or inflammation OR tissue trauma |
|
|
Term
In general, infections with anaerobic bacteria must be treated with... |
|
Definition
more than one antibioitc because often polymicrobic |
|
|
Term
What causes disease in infection with anaerobes? |
|
Definition
tissue destruction by action of proteases and lipases (lack exotoxins) |
|
|
Term
Describe clostridia (spore forming?, utilize O2?, shape?) |
|
Definition
spore forming anaerobic bacilli |
|
|
Term
The majority of exogenous anaerobic bacteria that cause disease all have which characteristics in common: |
|
Definition
gram positive, spore formers that cause disease either by the ingestion/inoculation of spores or products of the vegetative state in soil, water, food |
|
|
Term
Name four claustridium spore formers. |
|
Definition
tetani, difficile, botulinum, perfringens |
|
|
Term
Common characteristics of clostridial infections. |
|
Definition
forms spores (found in soil) and then germinate when they find an anaerobic environment in the body (wounds or GI tract). Virulence factors are exotoxins |
|
|
Term
Are clostridium normal flora? |
|
Definition
can be transient or permanent members of normal flora of skin and GIT of humans and animals |
|
|
Term
How do you control/treat clostridial infections? |
|
Definition
antibiotic therapy and tissue debridgement of necrotic tissue to decrease the anaerobic environment. Antitoxin therapy (passive immunity) and toxoid immunization is effective in controlling some clostridial infections that mediate disease via toxin production. |
|
|
Term
Which clostridia cause disease by ingestion or innoculation with spores which then germinate in host? |
|
Definition
tetanus (C. tetani), infant or wound botulism (C. botulinum), gas gangrene (C. perfringens), and pseudomembranous colitis (C. difficile) |
|
|
Term
Which clostridia cause disease by ingestion of toxins produced by vegetative cells growing outside the host? |
|
Definition
clostridial food poisoning (C. perfringens), or botulism (C. botulinum) |
|
|
Term
What types of diseases does C. perfringens cause? |
|
Definition
necrosis in gas gangrene and food poisoning in enteritis necroticans or diarrhea |
|
|
Term
Is C. tetani invasive? How does it cause disease? |
|
Definition
NO! it remains confined to the necrotic tissue where the vegetative cells of C tetani elaborate a toxin, tetanospasmin that then diffuses to neural cells. |
|
|
Term
How does teatnus toxin get into nervous system? |
|
Definition
thru neuromuscular junction of alpha motor neurons. The toxin is then transported to the otehr neruons, most importantly presynaptic inhibitory cells where it is no longer accessible to be neutralized by antitoxin |
|
|
Term
Once tetanus toxin gains access to inhibitory neurons, it blokcs the release of the neurotransmitters ____________. |
|
Definition
glycine and gamm-aminobutyric acid |
|
|
Term
clinical term for symptoms of tetanus= |
|
Definition
|
|
Term
How much tetanus toxin is considered lethal? |
|
Definition
|
|
Term
The highest mortality rates of tetanus are in persons... |
|
Definition
|
|
Term
What are the four kinds of teatnus? |
|
Definition
generalized, localized, cephalic and neonatal |
|
|
Term
What's another name for generalized tetanus? |
|
Definition
|
|
Term
What percent of tetanus is generalized? |
|
Definition
|
|
Term
What are the symptoms of generalized tetanus? |
|
Definition
first sign= trismus (lockjaw) and risus sardonicus (facial spasms), followed by stiffness of the neck, difficulty swallowing and rigidity of pectoral and calf muscles. Eventually can get opisthotonos. Also= high temp, sweating, high bp, and episodic rapid heart rate. |
|
|
Term
How long does tetanus last? |
|
Definition
3-4 weeks and complete recovery, if any, may take months |
|
|
Term
Localized tetanus is also called... |
|
Definition
|
|
Term
Is localized tetanus fatal? |
|
Definition
|
|
Term
Who gets localized tetanus? |
|
Definition
inadequately immunized patients |
|
|
Term
What is cephalic tetanus. |
|
Definition
rare form of the disease, occasionally occuring with otitis media in which C. tetani is present in teh flora of the middle ear. Or following head injuries. Involves cranial nerves, esp of face |
|
|
Term
What is neonatal tetanus? |
|
Definition
form of generalized tetanus in newborns when mother lacks immunity and the umbilical stump becomes contaminated with C. tetani spores. |
|
|
Term
How many infants die from neonatal tetanus? |
|
Definition
14% of neonatal deaths in developing countries with a 90% mortality rate |
|
|
Term
Why aren't you immune to tetanus after you've had it once? |
|
Definition
toxin is very potent so the amount released is too small to trigger immune mechanisms. Also, because the toxin binds firmly to neural tissue it may not interact effectively with teh immune system |
|
|
Term
One-half of all cases of tetanus worldwide are of what type? |
|
Definition
|
|
Term
What is the mortality rate of non-neonatal tetanus? |
|
Definition
|
|
Term
How long does the tetanus vaccine protect you for? |
|
Definition
|
|
Term
HTIG will only neutralize toxin that is... |
|
Definition
|
|
Term
How do you treat tetanus? |
|
Definition
vaccine, HTIG, local debridgement. Suprotive measures (resp assistance and IV fluids). Benzodiazepines (diazepam=valium). Penicillin historically but may act synergistically with tetanospasm so use metronidazole |
|
|
Term
What is the difference between infant botulism and food poisoning due to botulism? |
|
Definition
infants get sick due to germination of ingested spores. Adults get food poisoning due to ingestion of preformed toxin. |
|
|
Term
Is wound botulism due to infection with spores or toxin? |
|
Definition
|
|
Term
Adult form of intestinal C. botulinum colonization is very rare but can occur when... |
|
Definition
typically related to abdominal surgical procedures. Can be seen in older children and adults with abnormal bowels |
|
|
Term
What is injection botulism? |
|
Definition
seen in patients injected with inappropriately high ammounts of therapeutic neurotoxin (botox) |
|
|
Term
What is inhalation botulism? |
|
Definition
occurred in laboratory personnel who work with neurotoxins |
|
|
Term
Nervous system symptoms of botulism= |
|
Definition
blurred or double vision, dry mouth, difficulty swallowing, muscle weakness, muscle paralysis, and slurred speech. Can cause respiratory paralysis and death |
|
|
Term
Describe the neurotoxin of botulism? |
|
Definition
7 serologically distinct neurotoxins (A-G) with A being one of the most potent neurotoxins. Secreted as inactive toxin and must be cleaved by either bacterial or host protease. |
|
|
Term
C. botulinum causes a _________ paralysis. |
|
Definition
|
|
Term
T/F C. botulinum spores produce 7 serologically distince neurotoxins. |
|
Definition
False. toxins only produced by vegetative state |
|
|
Term
What is the pathophysiology of botulism toxin? |
|
Definition
toxin cleaves the polypeptides on synaptobrevins which are essential in triggering the release of acetylcholine into the synapse |
|
|
Term
How long does botulism paralysis last? |
|
Definition
permanent; muscle cell can only contract again in two to four months after the axon replaces the damaged nerve terminal |
|
|
Term
Long term sequale of botulism poisoning= |
|
Definition
fatigue and shortness of breath for years. longterm therapy may be needed to aid recovery |
|
|
Term
Which botulism toxins are the worst? why? |
|
Definition
Mort rate= A>E>B, which reflects the affinity of the toxins for neural tissue |
|
|
Term
Fatality rates of botulism is directly proportional to... |
|
Definition
|
|
Term
typical foods that give you botulism food poisoning= |
|
Definition
used to think was only associated with contaminated meat, esp sausage. but now know that it can grow well in vegitables, fish, fruits, and condiments. Most due to inadequate sterilization technique in home canning. |
|
|
Term
Which is more resistant to degredation botulism toxin or spores? |
|
Definition
spores are heat resistant and can survive 100 degrees C for hours |
|
|
Term
When do symptoms of foodborne botulism develope? |
|
Definition
12-36 hours after ingestion of contaminated food |
|
|
Term
Which toxins are most frequently associated with infant botulism? |
|
Definition
|
|
Term
At what age are you susceptible to infant botulism? |
|
Definition
|
|
Term
What are the symptoms of infant botulism? |
|
Definition
constipation, lethargy, sleepy, suck and gag reflexes diminish and dysphagia becomes evident with drooling. Head control is lost and infant becomes flaccid |
|
|
Term
Food implicated in infant botulism? |
|
Definition
honey; no longer recomended for infants under 1 year of age. Also, soil and dust |
|
|
Term
How do you treat infant botulism? |
|
Definition
antitoxin not routinely given. Use immune globulin called BabyBIG (botulism immune globulin), given IV. |
|
|
Term
C. botulinum can replicate in adult intestinal tract due to 2 common things... |
|
Definition
antibiotic therapy or achlorhydria |
|
|
Term
How do you treat botulism food poisoning? |
|
Definition
antitoxin that blocks the action of neurotoxn circulating in the blood. Some advocate antibiotic therapy. Removal of whatever contaminated food is left in gut via enema or vomiting. Surgically cleanse wound. Good supportive care |
|
|
Term
What toxins is botulism antitoxin against? |
|
Definition
A, B and E= trivalent antitoxin from CDC A, B, C, D, E, F, and G= heptavalent from US army or FEMA |
|
|
Term
What is the mortality rate of botulism? |
|
Definition
60% in 1940s to 10% today |
|
|
Term
Therapeutic botox is used for... |
|
Definition
involuntary muscle spasms (strabismus and certain focal dystonias), wrinkle remover |
|
|
Term
What type of toxin is in botox? |
|
Definition
|
|
Term
Which animals have cycles of botulism? |
|
Definition
|
|
Term
What GI diseases are caused by C. Difficile? |
|
Definition
spectrum of intestinal disease from uncomplicated antibiotic associated diarrhea to severe, possibly fatal, antibiotic associated colitis known as psuedomembranous colitis |
|
|
Term
Where is C. difficile found in the environment?/How is it spread? |
|
Definition
everywhere! soil, air, water, human and animal feces; inadequate handwashing |
|
|
Term
T/F C. difficile is a part of the normal GI flora. |
|
Definition
a small number 3% of healthy people naturally carry C diff in their large intestine but mostly C diff causes disease |
|
|
Term
Which antibiotics most often cause C diff infection? |
|
Definition
flouroquinolones, cephalosporins, clindamycin |
|
|
Term
What is pseudomembranous colitis? |
|
Definition
C diff infection that forms patches of raw tissue that can bleed or produce pus in the colon |
|
|
Term
What are the signs/symptoms of severe c diff infection? |
|
Definition
watery diarrhea 10-15x/day, abdominal cramping and pain, fever, blood or pus in stool, nausea, dehydration, loss of appetite, weight loss |
|
|
Term
What is the mort rate of pseudomembranous colitis? |
|
Definition
|
|
Term
How does C diff cause disease? |
|
Definition
produces toxin A and B (TcdA and TcdB). TcdA binds to apical side of the cell and after internalization cuases cytoskeleton changes that results in disruption of tight junctions and lossening of epithelial barrier. This allows TcdA and B to cross the epithelium. TcdB binds preferentially to the basolateral cell membrane. Both toxins are cytotoxic and induce the release of various immunomodulatory mediators from epithelial cells, phagocytesand mast cells, resulting in inflammation and PMNs. |
|
|
Term
What is a potential complication of C diff toxins entering the blood stream? |
|
Definition
TcdB has a tropism for cardiac tissue |
|
|
Term
Which group of people can have large numbers of Cdiff in their feces and still be healthy? |
|
Definition
infants (50% of neonates are carriers). Toxins are also present in the infants stools in the same amounts associated with adult disease but toxins typically have no adverse effect in infant, probably b/c they lack specific intestinal receptors for Cdiff toxins. |
|
|
Term
C diff manifests in AIDS patients as... |
|
Definition
|
|
Term
How long does a Cdiff infection last? |
|
Definition
1-14 days after offending antibiotic is dicontinued. Supportive therapy needed to compensate for severe fluid and electrolyte loss |
|
|
Term
Suspect C diff in anyone with diarrhea who has... |
|
Definition
taken antibiotics in the past two months or when diarrhea develops a few days after hospitalization |
|
|
Term
How do you diagnose C diff? |
|
Definition
look for toxins in stool (most use EIA test=fast but inspecific, with tissue culture assay=slow but accurate). Also colon examination for inflammation/pseudomembranes. CT can also show thickening of wall of colon |
|
|
Term
|
Definition
stop taking antibiotic. Take metronidazole for moderate dz or vancomycin for severe disease. Take probiotics (saccharomyces boulardii). Surgical removal of diseased colon. |
|
|
Term
Treatment of C diff that has recurred= |
|
Definition
antibiotics, probiotics (S. boulardii), stool transplant |
|
|
Term
Besides antibiotics what other drugs can cause C diff? |
|
Definition
antacids and proton pump inhibitors (losec) |
|
|
Term
What causes recurrent C diff diarrhea? |
|
Definition
50% d/t reinfection; 50% d/t relapse |
|
|
Term
What increases your risk of C diff diarrhea recurring if you've had it once? |
|
Definition
age >65 and exopsure to additional antibiotics |
|
|
Term
How does clostridium perfringens stain? is it sporeforming? |
|
Definition
gram positive spore former |
|
|
Term
Where in the environment is C. perfringens found? |
|
Definition
intestines of humans and animals and everywhere else in the environement |
|
|
Term
What diseases are caused by C. perfringens? |
|
Definition
gas gangrene, anaerobic cellulitis, endometritis, and food poisoning |
|
|
Term
|
Definition
acute dz with poor prognosis d/t trama compromising oxygen to tissues and subsequent growth of anaerobic bacteria |
|
|
Term
What are the symptoms of gas gangrene? |
|
Definition
initial= fever and pain in infected tissue; later= local tissue necrosis and systemic toxemia, purple mottling of infected muscle, edema and foul smelling exudate; gas bubbles form from products of anaerobic fermentation |
|
|
Term
How does C perfringens cause gas gangrene? |
|
Definition
multiply in wound and make various exotoxins (hemolysins, collagenases, proteases, and lipases that are liberated into the surrounding tissue causing more local tissue necrosis and systemic toxemia. |
|
|
Term
Which muscle groups are more frequently affected by gas gangrene? |
|
Definition
those in the extremities served by one or two major blood vessels |
|
|
Term
List chronic, systemic diseases that increase your risk of gas gangrene. |
|
Definition
atherosclerosis, chronic alcoholism, corticosteroid use, diabetes, GI malignancy, HIV, hypoalbuminemia, IVDU, malnutrition, obesity, PVD |
|
|
Term
What are the different types of C perfringens? |
|
Definition
five different types: A, B, C, D, E |
|
|
Term
Name important toxins of C perfringens. |
|
Definition
alpha toxin and theta toxin |
|
|
Term
|
Definition
toxin of c perfringens that is a lecithinase also called phospohlipase C. that lyses cell membrane lecithins, disrupting cell membranes and causing cell death |
|
|
Term
|
Definition
contributes to rapid tissue destruction in C perfringens infection by several mechanisms. Is an oxygen labile cytolysin that promotes direct vascular injury. Lower toxin concentrations activate PMNs and endothelial cells by promoting distal vascular injury. Causes leukostasis, thrombosis, decreased perfusion and tissue hypoxia. Also mediates production of shock |
|
|
Term
How does C perfringens cause shock? |
|
Definition
theat toxin mediates production of shock through induction of inflammatory mediators such as platelet activating factor, tumor necrosis factor, interleukin 1 and interleukin 6 |
|
|
Term
Describe C. perfringens endometriitis. |
|
Definition
necrotic products of conception in uterus can facilitate growth of C perfringens with subsequent infection of the endometrium. Necrosis and bactermia with intravascular hemolysis due to theta toxin may ensue. Very common after illegal abortion and the use of non-sterile instruments |
|
|
Term
Describe anaerobic cellulitis caused by C. perfringens. |
|
Definition
a milder form of gas gangrene with prominent gas formation |
|
|
Term
Describe immune response to clostridial wound infections. |
|
Definition
ineffective with no protective immunity. Conditions almost always fatal |
|
|
Term
How do you treat C. perfringens infection? |
|
Definition
debridgement, amputation, hysterectomy. Massive doses of penecillin and broad spectrum cephalosporins. Also, hyperbaric oxygen chamber |
|
|
Term
How does hyperbaric oxygen chamber help with c. perfringens infection? |
|
Definition
slows bacteria growth, toxin production, and oxidizes theta toxin |
|
|
Term
What are common sources of C perfringens food poisoning? |
|
Definition
beef, poultry, gravies, and dried or pre-cooked foods |
|
|
Term
What is the time frame and symptoms of C perfringens? |
|
Definition
incubation for 8-24 hours after ingestion of contaminated food. Symptoms are diarrhea, cramps, and abdominal pain. (rarely= fever, nausea, and vomiting). Lasts for 24 hours |
|
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Term
What species of C perfringens causes food poisoning? |
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Definition
type A makes an enterotoxin that affects the permeability of the plasma membrane of mammalian cells |
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Term
What is the mortality rate of C. perfringens food poisoning? |
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Definition
essentially zero but elderly and ICX patients should be closely supervised |
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Term
How do you diagnose C perfringens food poisoning? |
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Definition
detect bacterial toxin in feces or by tests to determine the number of bacteria in the feces. At least 106 spores/gram of stool wtihin 48 hours of when illness began to dx infection |
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Term
Wound contamination by clostridium spores which germinate in situ to produce toxins= |
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Definition
either C tetani producing tetanus or C. perfringens producing gas gangrene |
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Term
Contamination of food with clostridia spores which germinate under anaerobic conditions= |
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Definition
either C botulinum producing flaccid paralysis or C perfringens producing diarrhea or enteritis necroticans |
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Term
ingestion of spores in honey which germinate= |
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Definition
c. botulinum in infant botulism |
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Term
Which clostridium species is an opportunistic pathogen? |
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Definition
c diff causing pseudomembranous colitis |
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Term
Special considerations of anaerobic infection laboratory diagnosis: |
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Definition
1) slow growth of organism, 2) contamination free specimen, 3) protect specimen from O2, 4) often members of normal flora, 5) polymicrobic |
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Term
How do prevent tissue sampels from O2 exposure? |
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Definition
placed into a degassed bag and sealed or into a glassed out screw top vial that may contain oxygen free pre-reduced culture medium, tightly capped and plated as rapidly as possibly onto culture media that has been prepared for anaerobic transport and culture |
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Term
THe BBL vacutainer anaerobic specimen collector is media free because... |
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Definition
this helps to minimize sample dilution |
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Term
HOw do you know you're anaerobic jar is actually anaerobic? |
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Definition
methylene blue strip is only blue in the presence of oxygen. Will be colorless if jar is anaerobic |
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