medically important bacteria Flashcards
borrelia
lyme disease
C diff characteristics?
anaerobic spore forming bacillus
-the toxin it makes is the problem
-feccal oral transmission, noscomial infection
-most common cause of infectious diahrrea in the hospital
-major cause of antibiotic associated colitis
most common antibiotics that lead to cdiff
clindamycin and ampicillin
fever, abdominal, pain, diahrrea, leukocytosis, hypoalbuminemia, anasarca, actue kindey injury, edema, arthritis, ascities are s+s of?
c.diff
how to diagnose c diff
enzyme immunoassay (EIA) for glutamate dehydrogenase of c.diff
what is glutamate dehydrogenase
an antigen
-essential enzyme produced
-this does NOT distinguish between toxogenic and nontoxogenic strains
-fast results
cdiff pcr
detects toxin a and b genes
-high sensitivity and potential for a false positive
-use a broad spectrum gi panel too bc not all c diff causes problems
how to manage cdiff?
-discontinue antibiotics
-hydration
-electrolyte replacement
-avoid antimotility agents due to the risk of toxin megacolon
-bleach
-hand washing
-alc does NOT work
why do you have to use oral vancomycin?
bc it is the only thing that will target the c diff, iv would not treat it
-oral can not enter the blood stream so ONLY for c diff
what is pseudomembranous colitis?
more severe c diff with major gut inflammation
-damage and ulcerated tissue
-can also be part of CMV, e coli, salmonella, IBD, medication
-hemorrhagic mucosa, edematous and ulcerated
-colon succeptible to hypoxia
what is a patient cant tolerate oral vancomycin?
-intracolonic vancomycin
what is bezlotuxomab?
a monoclonal antibody to prevent recurrence cdiff
-neutralizes toxin B
do you treat asymptomatic carriers?
no
-many shed it wit h no diahrrea or active infection
pseudomonas aureginosa si typically what kind of infection?
nosocomial pathogen
where is p. auregenosa typically found?
decaying vegetation
-they are non-fermenters but metabaolize many things
what kind of bacteria is p. auregenosa?
gram neg rods
why does p.auregenosa typically need to be treated many times?
it has a high virulence factor and normally does not clear with first time treatment
t or f p. auregenos ais an aerobe
-yes but it could grow anaerobically
exotoxin A, biofilm, capsule, elastases, proteases, siderophores belong to what?
p.auregenosa virulence factors
what makes p.auregenosa antibiotic resistant?
it can efflux antibiotic out
-porins and beta lactamases
-biofilm also helps
what sydromes can p. auregenos infection cause?
pneumonia, skin infection (burn victim, folliculitis, ecthyma gangrenosum) , uti, otitis externa
-bad for ventilators and CF pts
-sepsis in immunocomp
-nail infection, contacts, diabetic foot infection, neurosurgery hardware
where is p.auregenosa most common
-in hopsital
-ventilator pneumonia
-surgical site infection
-catheter uti
what does p.auregenosa look like on culture media?
green
how can you identify p.auregenosa?
-green color of pyocyanin
-grape juice scent
-metallic sheen
-pt might just be colonized not infected
how do we treat p.auregenosa?
zosine, ticarcillin, cefepime, ceftazidime, carbapenems, aminoglycosides
-remove the hardware/ catheter
-debridement of necrotic tissue
-sometimes might need to combo 2 abx
how would you treat a pt ventilated with pseudomonas?
-change the tube
-ct to check for evident of pneumonia
-antipseudemonas abx
why is limiting broad spectrum antibiotics helpful for pseudomonas?
-reduces resistance
what is staphylococcal main virulence factor?
methicillin resistance and sensitivity
-first line treatment often doesnt work
where can we find staph in patient?
lung, csf, meningitis,
where can we find staff out patient?
mrsa
what is mrsa?
methicillin resistant staphylococcus
t or f staph is a normal flora of skin and mucosa?
t
complications of staph/ types of staph infections
-skin soft tissue, bacteremia, endocarditis, osteomyelitis/ septic arthritis,
enzymes (coagulase, leucocidin) that destroy and spread through tissue, protease, nuclease, fibrinolysin, biofilm, hyaluronidase (spread factor), enterotoxin, tss, are all virulence of?
s.aureeus
what is enterotoxin?
food poisoning
-dont need antibiotics the toxin stimulates the gut and you get sick and vomit
leucocidin
destorys wbc
-s.aureus
what if u have a skin infection?
drain the abscess, send the fluid to lab to culture, may need antibiotic if it is causing cellulitis so monitor surrounding tissue
staph toxin causes?
-food poisoning
-tss (fever hypotension, multi system involvement, rash erythroderma, tampon or foreign body)
staph scalded skin syndrome
toxin is produced that peels off the top layer of skin
what is methicillin resistance mediated by?
-pbp-21 (a penicillin binding protein encoded by the mecA gene that permits the organism to grow and divide in the presence of methicillin and other beta lactam antibiotics)
risk factors of mrsa
-abx, hiv, iv drug usage, catheter, long term care, hospitalization
how to diagnose mrsa?
pcr that targets the mecAgene
-blood culture (much slower)
what is the main cause of bacteremia related to drug users?
s aureus
-this is a direct inoculation
other common causes of s aureus bacteremia
intravascular catheter, chronic hemodyalysis, skin infection, uti, surgery
complications of bacteremia
-sepsis and metastatic infection that can cause endocarditis and abscesses
1 cause of bacterial endocarditis?
s.aureus
-native or prosthetic valve
-common in IV drug users
complications of endocarditis from s aureua
heart failure, valve destruction, metastatic infection/ septic emboli
what is a common cause of strep pneumonia?
alpha strep
-protection from the strep pneumoniae vax
otitis media, peritonsillar abscess, sinusitis, strep throat can be caused by?
group a strep
complications of group a strep
rheumatic fever, scarlet fever, acute glomerulonephritis
-happens bc it triggers the immune system
how to diagnose strep?
tonsillar exudate (white patches), tender anterior cervical lymphadenopathy, fever without a cough
what is the test for step
-throat culture, rapid antigen detection test (RADT) or molecular point of care test (POC) for GAS
how are we going to treat gas?
-reduce symptoms, prevent complications and spread, prevent RF, pnc/ amoxicillin
what are alternatives abx for gas
-cephalosporins, clindamycin, macrolides
what is scarlet fever and what can it lead to?
a delayed skin rx to the toxin
-high risk of developing into rheumatic fever
what toxin does strep produce?
-erythrogenic toxin type A, B or C
characteristics of scarlet fever
-blanches with pressure, papular elevations, “sandpaper skin”, starts in groun and armpits, strawberry tongue, covers the tunk, predisposes acute RF
what can RF lead to years later
cardiovascular disease
how long until the signs of RF from a strep infection?
-latent period of 2-3 weeks till first symptom appears
what is rf?
-systemic inflammation, carditis, arthritis, affects large joints, valvulities, can sometimes spread to cns, nodes
how to treat rf?
eradicate group a beta hemolytic strep (gas)
-manage symtoms
