infectious disease Flashcards
what are 4 major gram + cocci bacteria? how are they shaped?
staphylococcus aureus - grapes/clusters
staphylococcus epidermitis: grapes/clusters
streptococcus viridans (GABHS) - chains/pairs
Streptococcus pneumococcus - chains/pairs
Staph aureus is found where? how is it spread?
normal flora of skin/nose, spread thought lesions, fomites
in diagnosis, how is staph differentiated from strep?
staph has catalase (is catalase positive) - aka when its added to hydrogen peroxide, O2 is produced.
treatment options for staph? MRSA?
methacillin, nafcillin, dicloxacillin (PCNs)
if MRSA- vancomycin
what diseases can staph aureus cause? (7)
skin infections, bacteremia/sepsis, acute endocarditis, PNA, osteomyelitis/septic arthritis, food poisoning, TSS
what does Staph epidermitis infect?
assoc. with IV catheters and damaged/ prosthetic heart valves –> insidious onset and less virulent
what diseases does strep (GABHS) cause? (5)
skin infection, pharyngitis + scarlet fever + rheumatic fever, mitral valve disease, acute glomerulonephritis, TSS
where is strep viridans found and how does it spread?
throat/skin spread through resp. droplets
how is strep diagnosed?
catalase negative
beta hemolysis and bacitracin sensitivity = GABHS
treatment for strep?
PCN to prevent rheumatic fever
what disease does strep pneumo cause? (3)
lobar PNA, adult meningitis, URI (kids)
- found in nasopharynx
what are the 2 gram - cocci? what shaped are the?
Neisseria meningitis and Neisseria gonnorhoeae
both: kidney bean shaped
how do you differentiate the two gram - cocci?
N. meningitis ferments maltose
N. gonorrhoae does NOT ferment maltose
what 3 dz does N. meningitidis cause?
meningococcemia (w/ petechial rash)
meningitis (w/ increased PMNs in CSF)
waterhouse friedrichsen (fever, purpura, DIC, bilateral adrenal hemorrhage, shock, death)
what dz does N. gonorrhea cause?
males- urethritis, epididymitis, prostatitis
female- cervicitis, infertility, PID, ectopic, ophthalmia neonatorum
both- septic arthritis
treatment for gram - cocci (Neisseria meningitidis and gonorrhoaea)? prophylaxis?
ceftriaxone (general 3 cephalosporin)
prophylaxis: N. meningitidis - rifampin, N. gonnorhoaea - erythromycin eye drops for newborns
what is the likely bacterial meningitis in 0-6months? 6mo - 3 yrs? 3-15yrs? >15 yrs?
0-6mo : group B strep, E coli, Listeria
6mo - 3yr: H flu B
3yr- 15 yrs: N. meningitidis
>15yrs: Strep pneumo
what are the gram + rods? (3)
Clostridium ( C. tetani, C. botulinum, C. perfungens, C. difficile)
Corynebacterium diptheriae
listeria monocytogenes
what bacteria group are all anaerobic, spore-forming, and with exotoxins ?
gram + rods Clostridiums
what is the MOA of C. tetani? C. botulinum?
tetani: blocks release of inhibitory glycine neurotransmitter
botulinum: blocks Ach release
what is the MOA of C. difficile?
suppression of normal flora allows overgrowth, meds that cause this - clindamycin, ampicillin, cephalosporins
treatment for gram + rods?
C. tetani - tetanus immunoglobin +/- (prevention tetanus toxoid)
C. botulinum - antitoxin
C. perfingens - debridement, O2 gas, PCN
C. Diff - metronidazole, vancomycin
Diptheriae- antitox, PCN
listeria- ampicillin
what antibiotic can you NOT use for C. botulinum? why?
PCN will burst cells and release the toxin
what does the gram + rod diptheria cause? (3)
gray fibrinous exudate in throat (pseudomembrane) - airway obstruction, myocartidis, recurrent laryngeal nerve palsy
what does the gram + rod listeria monocytogenes cause?
neonatal meningitis and sepsis, premature delivery
where does listeria monocytogenes come from?
transmitted to humans from animal feces, veggies, UNPASTURIZED MILK/CHEESE
what bacteria are included in the gram - rods? (4 major groups with subgroups)
- Enteric- E coli, Salmonella, Shigella, Vibrio (cholera), campylobacter, helicobacter pylori
- Enteric-extraintestinal - klebsiella, pseudomonas
- Respiratory- H flu, legionella, pertussis
- zoonotic- brucellosis, tularemia, yersinia pestis (plague), pasturella
what does E coli cause? (4)
MC- UTI, gram - sepsis, traveller’s diarrhea (watery), neonatal meningitis
*can produce blood if it produces shiga toxin
how is E coli differentiated from salmonella and shigella on dx?
it DOES ferment lactose
Ecoli treatment
generation 3 cephalosporin (ceftriaxone, cefixime)
what does Salmonella cause? (3)
gastroenteritis ( diarrhea +/- blood ), typhoid fever, gram - sepsis
how can you distinguish salmonella from Ecoli and shigella on dx?
does NOT ferment lactose like Ecoli does
DOES produce H2S gas + enters bloodstream (unlike shigella)
treatment for salmonella
PCN - ampicillin, amoxicillin doxycycline TMP/SMX Ceftriaxone cipro
what 3 bacteria are NOT susceptible to TMP/SMX?
pseudomonas, tularemia, mycoplasmae
what causes these? gross bloody diarrhea, small blood diarrhea, traveller’s diarrhea, massive rice-water diarrhea, daycare outbreak diarrhea
gross blood- campylobacter small blood- salmonella traveller's - Ecoli (+/- watery, blood) massive/rice water - cholera daycare- shigella
transmission and patho of shigella?
NOT normal human flora, fecal - oral, invades distal ileum + colonic, NOT spread through blood (like salmonella)
treatment for shigella and cholera?
rehydrate
treatment for campylobacter
macrolide (azithromycin, erythromycin)
macrolide coverage (azithromycin, erythromycin, clarithromycin)
gram + and some gram - (H flu, pertussis)
aminoglycoside coverage (gentamycin, streptomyocin, tobramycin, amikacin)
aerobic gram - ( enterobacter, pseudomonas)
tetracycline (doxycycline) coverage
broad: aerobic, anaerobic, gram + and gram -
what does helicobacter pylori cause?
gastritis, peptic ulcer, risk for gastric carcinoma
Dx helicobacter pylori
urease +
Txt for helicobacter pyloric
tetracycline, metronidazole
what does gram - rod klebsiella-enterobacter-serratia cause?
opportunistic pathogen - UTI, PNA
severe, bloody sputum, lung cavitation
what does gram - rod pseudomonas cause?
opportunistic pathogen - PNA, osteomyelitis, burn infection,malignant otitis externa
treatment for pseudomonas
- pipercillin- ticarcillin (extended specturm PCN) and aminoglycoside (gentamycin)
- ceftazadime ( gen 3)
what does H flu cause?
leading cause of meningitis in kids, epiglottitis
txt for HIB?
rifampin (prevents meningitis and transmission)
what does legionella pneumophilia cause?
atypical pneumonia with high fever, productive cough
airborne from water sources
txt for gram - rods legionella?
macrolide (erythromycin)
how do you get campylobacter?
gram - rod, ingestion of contaminated food or from domestic animal
what is the ONLY abx that will cover listeria?
ampicillin
CSF of lyme disease that has disseminated into CNS will show what? how is it treated ?
lymphocytes and moderate increase in proteins
CNS lyme = ceftriaxone
txt for latent TB
isoniazid for 9 months or Rifampin for 4 months
what medication is given with isoniazid to prevent neuropathy?
pyridoxine
treatment for lyme disease in pregnancy/children?
amoxicillin
compare and contrast rubella and rubeola (measles)
both start on face and spread downward BUT rubeola (measles) has a prodrome of cough, coryza and koplik spots.
“rub lotion on your face first, then your body”
“rub it all over if it starts with cough, coryza, koplik”
child with HIGH fever for 4 days, then a blanching, nonpruritic rash that starts on the trunk and spreads outwards
roseola
“blooms from inward to out like a rose”
slapped cheeks and lacy exanthem… what is the disease and the virus that causes it?
erythema infectiosum (parvovirus B19)
CSF for meningitis: INDIA INK STAIN shows encapsulated yeast forms ?
cryptococcus neoformans
What finding on a Tzank smear confirms the diagnosis of an HSV infection?
multinucleated giant cells
condyloma accuminata is what? condyloma lata is what?
accuminata: genital warts (HPV)
lata: secondary syphillis (flat velvety moist near the chancre)
Patients diagnosed with chlamydia or gonorrhea should be counseled to avoid sexual contact for how long?
7 days after finishing the abx
what disease comes from unpasturized milk products or handling meat/animals and causes undulating fever (high during the day at low at night)?
Brucella (gram - rod)
what disease comes from an animal/mite bite and causes ulceroglandular lesions (holes in skin, black base, swollen lymph and draining pus) ?
Tularemia (gram - rod)
what disease comes from prairie dogs/ rats/ fleas from urban centers?
yersinia pestis (black plague) (gram - rod)
what disease comes from normal flora or cats/dogs, transmitted through a bite, causes RAPID cellulitis from the bite and possible osteomyelitis?
pasturella multocida
what is the treatment for pasturella ?
PCN
what are the acid-fast rods?
Mycobacteria tuberculosis and mycobacterium Avium
treatment for mycobacterium avium?
Azithromycin or clarithromycin
what is type of organism is mycoplasma pneumoniae? what does it cause?
small-free living, virus- like.
walking pneumonia
Dx and treatment for walking pneumonia
Dx- positive cold agglutinins
Txt- erythromycin or tetracycline
what are the 4 “big dogs” of Abx?
doxycycline (a tetracycline)
clindamycin
linezolid
TMP/SMX (bactrim)
what is amphotericin B used to treat? (3)
fungal sinusitis, cryptococcosis (MC fungal meningitis), candidal endocarditis
both from inhaled bird droppings, what regions are cryptococcosis and histoplasmosis found?
cryptococcosis- southwest
histoplasmosis - midwest
how do you diagnose cryptococcosis?
india ink stain = encapsulated yeast
how is histoplasmosis (atypical PNA) diagnosed?
sputum PCR
what is the treatment for PJP?
TMP/SMX (bactrim)
how are most helminths diagnosed?
eosinophilia
* trichenollosis = muscle biopsy shows larva in striated muscle
how are most helminths treated? what if the pt is pregnant?
albendazole or mebendazole
*pyrantel if pregnant
what is enterobius vermicularis? how is it treated?
pinworm
txt: albendazole/mebendazole
what are the ToRCH syndrome diseases? what can they cause?
Toxoplasmosis, other (includes Zika now), Rubella, CMV, Herpes
- congenital: blueberry muffin rash (TTP), hearing loss, hepatosplenomegaly, developmental delays
what shows “ring-enhancing lesions” on CT/MRI? what is the source?
toxoplasmosis (protozoa from cat feces or uncooked meat)
treatment for toxoplasmosis? what if they are currently pregnant?
sulfadiazene (or clindamycin) + pyrimethamine. (w/ folinic acid and leuovorin to prevent bone marrow suppression)
PREGENANT = SPIRAMYCIN
what does trichenellosis cause?
GI upset –> muscle phase (myositis + periorbital edema) –> PNA + CNS involvement
how is botulism treated?
<1 yo - human-derived antiTox
>1yo - equine-derived antiTox
what treatment is used for wound botulism but NOT for foodborne type? why?
wound - PCN G
*may worsen dz from bacteria lysis toxin release
what is nucleic-acid amplification used to diagnose?
chlamydia, gonorrhea, trichomoniasis
friable white exudate that bleeds when scraped off can be a sign of what two things?
thrush (oral candida) and diptheria
treatment for diptheria
equine- antiTox +erythromycin or PCN
signs and symptoms of salmonella?
- pea soup diarrhea +/- blood (gastroenteritis) +crampy abdominal pain
- typhoid (enteric)fever: + fever, bradycardia, rash
- osteomyelitis (if sickle cell)
how is salmonella diagnosed?
blood culture
treatment for salmonella and shigella ?
fluids +/- TMP/SMX or fluoroquinolones
sign of shigella?
BLOODY diarrhea +/- sigmoidoscopy showing areas of ulceration
MC cause of erysipelas? cellulitis?
erysipelas - group A strep
cellulitis- staph
treatment of erysipelas?
IV PCN or vancomycin if PCN allergy or MRSA
what type of rash does TSS cause?
diffuse erythematous (sunburn-like) + desquamation
treatment for TSS
admit, fluids, clindamycin + vancomycin
treatment for MRSA
TMP/SMX
signs and symptoms of rheumatic fever
JONES criteria (major): Joints, Oh No carditis, Nodules, Erythema marginatum, Syndeham chorea minor: fever, polyarthalgia, increased ESR/CRP, prolonged PR interval
modified jones criteria for 1st infection: how many major/minor do you need
+ strep test plus 2 major OR 1 major, 2 minor
Txt for rheumatic fever
ASA for carditis, PCN
*macrolides if PCN allergic
what two viruses do you need acyclovirs for?
CMV - ganiciclovir
herpes- acyclovir
*the rest are supportive
Dx of CMV
PCR
3 complications of mono?
encephalopathy, meningitis, guillan barre
what CA is mono assosciated with?
hodgekins lymphoma (Burkitts)
peripheral smear for mono shows what?
> 10% atypical lymphocytes
erythema infectiosum : how can it present in children? adults? sickle cell pts?
aka parvovirus B19
children: slapped cheeks –> lacy reticular rash
adults: + arthropathy
SS: aplastic crisis
“1st is the worst” applies to what virus?
herpes, first outbreak is the worst/most painful
CD4 count and associated diseases( < 200, <150, <100, <50). which do you prophylax for?
< 200: PJP w/ TMP/SMX
< 150: histoplasmosis w/ fluconazole
< 100: toxoplasmosis w/ TMP/SMX + cryptococcosis
<50: CMV + MAC
diagnosis of rabies?
PCR
what is ramsey hunt syndrome?
Varicella-zoster involvment of genicular/facial nerve: vesicular rash in ear, unilateral facial paralysis, tinnitus/hearing loss
treatment for ramsey hunt?
acyclovir + steroids, maybe TCA or gabapentin for facial paralysis
Dx for TB and MAC?
acid-fast bacilli
treatment for MAC?
clarithromycin + ethambutol
what are the 3 spirochetal diseases?
lyme, RMSF, syphillis
Dx of lyme?
ELISA test, Western blot
Dx of syphillis?
RPR and VDRL, confirm with FTABS
what organism causes acute sinusitis? chronic sinusitis?
acute: Strep pneumo, H flu, Mcatt
chronic: staph aureus
txt for bacterial sinusitis?
Amox
second line - doxycycline or TMP/SMX
treatment for AOM?
amox or augmentin or cefdinir
MC route of infection for PNA
microaspiration of oropharyngeal secretions
CAP organisms vs HAP organisms
CAP: S pneumo, Hib, Mcatt. *atypical (mycoplasma pneumo. aka walking PNA)
HAP: gram neg rods (pseudonomas, E coli, klebsiella)
what organism causes PNA after a viral illness like the flu?
Staph aureus
klebsiella PNA shows what on CXR?
cavitary lesions
macrolides have what kind of coverage? in general what infections are they good for?
gram + with some gram neg. good for resp. infections
CXR for PNA
sillouhette sign
- lobar = typical
- patchy interstitial = atypical
what is CURB 65?
assessment to see if PNA needs hospitalization. Confusion, Urea >7mmol, RR >30, BP <90/60, age >65
each counts for 1. score 3-5 = admission
txt COPD exacerbation
bronchodilators, O2, steroids
+ Abx (azithromycin) if increased/ change in sputum or CXR showing infection.
treatment for cellulitis
cephalexin, amox or dicloxacillin
MRSA= TMP/SMX, doxy or clinda
who is most likely to get osteomyelitis?
MC <20yo or immunocompromised
organisms that cause osteomyelitis?
Staph aureus (also GABHS)
immunocompromised - salmonella
prosthetic - Staph epidermis
IV drugs - pseudomonas
treatment for osteomyelitis?
staph/strep = PCN or vancomycin salmonella/pseudomonas= FQ
txt for pyelonephritis
FQ for 14 days
prostatitis organism and treatment : <35yo vs >35yo
<35 yo : Gonorrhea/chlamydia : ceftriaxone + doxy/azithromycin
>35 yo : E coli : FQ or TMP/SMX
which valve is MC infected with endocarditis? what if its from IV drug use?
mitral valve (but it IV drug use = tricuspid)
acute vs subacute endocarditis?
acute: normal valve, virulent organism (staph aureus)
subacute: abnormal valve, less virulent (strep viridans)
what organisms cause endocarditis for those with prosthetic valve? IV drug use?
prosthetic valve: Staph epidermitis
IV drugs: MRSA, pseudomonas, candida
endocarditis within <60 days of inoculation? >60 days?
<60 days : most likely prosthetic valve
>60 days : native valve
Dx endocarditis
blood culture before antibiotics, 3x 1 hr apart each.
CBC, EKG, Echo
txt for endocarditis (acute, subacute, prosthetic, fungal): time period and drugs for each
4-6 weeks of …
acute: nafcillin + gentamicin (aminoglycoside)
subacute: nafcillin + gentamicin + ampicillin
prosthetic: gentamicin + vancomycin + rifampin
fungal: amphotericin B
what do aminoglycosides (GNATS) cover?
primarily gram neg (pseudomonas, enterobacter) and TB
secondary syphillis shows what?
diffuse rash, palms + soles w/ desquamation + lymphadenopathy
what is the jarisch-hercheimer rxn?
24 hrs after syphillis treatment = flu-like symptoms from the detox
what causes spontaneous bacterial peritonitis?
portal HTN –> bowel edema –> bacterial migration from GI tract
Dx of spontaneous bacterial peritonitis?
paracentesis: fluid has >250 PMNs
treatment for spontaneous bacterial peritonitis? what bugs is it to cover?
cephtriaxone (or other 3rd gen cephalosporin)
- covers Ecoli, klebsiella, strep pneumo
dx of bacterial meningitis?
high opening pressure, CSF predominance of neutrophils >1000, decreased glucose, increased proteins
organisms of meningitis: <1 mo, 1mo-18yrs, 18-50, >50
<1mo: group B strep, Listeria
1mo - 18 yrs: Neisseria meningitis MC, S pneumo, Hflu
18-50: S pneumo MC, N. meningitis, Hflu
50+: S pneumo, Listeria
txt for meningitis: < 1mo, >1mo-50, 50+
<1mo: ampicillin + 3rd gen cef or aminoglycoside
>1mo - 50: 3rd gen cef + vancomycin
50+: ampicillin + 3rd gen cef
uncomplicated UTI txt?
5-7days
macrobid (nitrofurantoin)
*or FQ, TMP/SMX
complicated UTI/pyelonephritis txt? pregnant?
14 days
FQ or aminoglycoside
pregnant = amoxicillin or macrobid(nitrofurantoin)
what makes a UTI complicated?
> 7 days, pregnant, DM, immunocomprimised, elderly, male
