other gram positives Flashcards
draw the algorith for gram positive bacteria
what do all clostridium have in common ?
all form spores
all are obligate anaerobes
all form toxins
what are the obligate intracellular anaerobes ?
rickettsia
chlamydia
coxiella
clostridiu,
who are the pore forming bacteria ?
ABC
autoclave to kill bacillus and clostridium
where is clostridium tetani found and how do they enter the body ?
spores are found in the soil
enter through penetrating injuries , as with walking barefoot
what is the toxin of tetanus and what does it do ?
tetansopasmin
retrograde axonal transport to CNS
blocks glycine and GABA release by inhibitory neurons
attacks renshaw cells
causes spastic paralysis
what are the classic spasm of tetanus ?
lock jaw
risus sardonicus ( permanent smile)
what is the treatment of tetanus?
debriement of the wound
metronidazole
tetanus immunoglobulin
benzos or neuromuscular blockers
what is in the vaccination for tetanus ?
the toxoids
what is so special about botulinum spores ?
produce heat labile toxins that damages SNARE proteins
what is the mechanism of botulinium toxin ?
Forms a heat labile toxin that cleaves SNARe protein that then
blocks the release of ACH so no muscle contraction
leads to flaccid paralysis
where is the DNA for c botulinium usually found ?
found in many different variants
carried by bacteriophages
what are the three types of botulinium and what are their features ?
food - usually in adults , from canned undercooked food
infant - ingestion of spores , grow in intestines , associated with honey, floppy baby syndrome
wound - infection
what are the symptoms of botulism ?
usually ocurs after 12-48 hours of ingestion
5D symptoms :
diplopia
dysphagia
dysphonia
descending flaccid paralysis
NO SENSORY DEFECITS
what is the treatment of botulism ?
antitoxin
supportive care
where is clostridiu perferinges found ?
widespread in soil
what are the effects of infection by c perferinges ?
causes gas gangrene - clostridial myonecrosis
what is the toxin associated with clostridium perferinges ?
alpha toxin
causes hemolysis of muscles
it is a phospholipase that acts on lecithin and degrades it in the cell membrane
what bis the presentation of food poisoning in association with c perferinges ?
1- it happens after the ingestion of the spores in association with undercooked meats
2- late onset with watery diarrhea because the ingestion of spores makes the presentation late
what is the classic clinical scenario associated with c difficile infection ?
ingestion of the spores are not harmful
colonic flora prevents the overgrowth
the environment only becomes favourable after antibiotic administration
what bacteria is associated with antibiotic associated colitis ?
c difficile
what are the toxins associated with c difficile ?
toxin a - enterotoxin causes watery diarrhea
toxin b - cytotoxin causes cell necrosis and fibrin deposition
toxin b is more potent
what is the mechanism of action associated with the toxins made by c difficile ?
both toxins bind to GI cells and are internalized
destroy the cytoskeleton of GI cells and form a pseudomembrane
massive watery diarrhea and history of ab therapy ?
suspect c difficile
how is a diagnosis of c difficile made ?
stool detection of toxin a or b
what is the treatment for c difficile ?
metronidazole
ORAL vancomycin
what is the toxin associated with diphtheria annd what is the associated mechanism ?
diphtheria exotoxin
not part of bacterial genoe
carried by b prophage
inactivates EF2 by ADP ribosylation
what is the shape of corynebacterium features ?
club shaped gram positive rods
Chinese character distribution
what are the media used for c diptheria ?
loefflers media or tinsdale
what test is used for the diagnosis of diphtheria ?
elek test for diagnosis and toxin detection
what are the symptoms of diptheria ?
gray white membrane in the back of the throat
lymphadenopathy
fever
sore throat
what is the treatment for acute infection of diphtheria ?
penicillin
diphtheria anti toxin ( passive immunization)
diphtheria toxoid ( active immunization )
how is a lab diagnosis of diptheria made ?
based on gram positive rods with metachromatic granules and positive elek test for toxin
what is the unique moving mechanism of listeria ?
tumbling motility
moves from cell to cell to avoid extracellular responses
it polymerizes actin in cells to move “ actin rockets”
what is the virulence of diptheria toxin ?
encoded by B prophage that allows of ADP ribosylation of elongation factor 2
what type of patients are most likley to get listeria ?
in people with poor cell mediated immunity
in adults who consume undercooked meats
unpasteurized cheese or milk
likes cold temperatures
what are the three clinical pictutes associated with listeria ?
gastroenteritis - self limited
meningitis - elderly or newborns
infection in pregnancy - usually in 3rd trimester
what happens if a pregnant mother infects her foetus with listeria ?
newborn gets granulomatosis infantiseptica
severe in utero infection
most babies will be still born
what is distinctive in the placenta with babies that develop granulomatosis infantiseptica ?
chorioamnionitis
villitis
abscess formation
what are the two types of bacillus ?
bacillus anthrax
baciilus cereus
which is the only bacteria with a polypeptide capsule ?
bacillus anthrax and contains d-glutamate
most are polysacchrides
what type of workers are more at risk of bacillus anthrax ?
farm workers
what are the toxins associated nwith bacillus anthrax ?
protective factor
edema factor- acts as adenyl cyclase and increases cAMP
lethal factor-inhibits MAP kinase, allows for macrophage apoptosis
what is the cutaneous disease of anthrax ?
painless black ulcer forms
edema surrounds the black ulcer from edema factor
what is the clinical picture associated with the pulmonary disease of anthrax ?
woolsorters disease , caused by the inhalation of spores
fluu symptoms then eventually may cause pulm hge
what is the classic finding on chest x ray of people with wool sorters disease ?
wide mediastinum
what is the classic scenario associated with bacillus cereus ?
classically in undercooked or reheated rice
cause by ingesting the enterotoxin
reheated rice syndrome
what are the two types bacillus cereus disease ?
emetic type - rice dished direct ingestion of toxin
diarrheal type - caused by several enerotoxins , heat labile toxins
what gram positive bacteria is normally found in both the oral flora and in the female genital tract ?
actinomyces
what is the shape of actinomycen ?
long filaments resembling fungi
what is the classic disease presentation associated with actinomyces ?
head and neck abscess
if there is an IUD associated infection what is the most likely causative organism ?
actinomyces
dental work , or orofacial truma followed by a mass on the face ?
associated with actinomyces
what colour is associated with actinomyces ?
yellow sulfur granules
what is the only bacteria that is acid fast that isnt mycobacterium ?
nocardia
what are the urease positive organisms ?
Pee CHUNKS
proteus
cryptococcus
H pylori
Ureaplasma
Nocardia
Klebsiella
S epidermidis
what are the 2 illnesses associated with nocardia ?
pneumonia because they are obligate aerobes
skin infections
how does the skin infection happen in nocardia ?
invades the skin during gardening or farming
what is the drug of choice when treating nocardia ?
TMP-SMX which is sulphonamide
what are the lab indications of recent strep pyogens infection ?
ASO titre
anti-DNase B antibodies
what is medusa head an indication of ?
bacillus anthrax
what disease mimics nocardia ?
TB but with a negative PPD
what is the treatment of actinomycen ?
penicillin
what can cause PID in association with IUDs ?
actinomycen
how can clostridium perferinges be associated with colonic malignancies ?
most commonly caused by clostridium septicum
