diagnostics Flashcards
staphylococcal scalded skin syndrome
clinical presentation and bx and cx that produces nothing because the bullae are sterile
media for chancroid isolation requires
growth supplements
cross like morphology in RBCs
babesiosis
dermatophyte dx that allows for early detections
dermatophyte test medium (DTM), will have results in 3 days based on phenol red color change (pH)
UTI- dipstick
leukocyte esterase and nitrites
can you gram stain gonorrhea
yes but the sensitivity is not great
RMSF gold standard dx
direct immunofluorescence w/ a R. rickettsii antigen (2 samples, 2-4 weeks apart)
dimorphic species that can grow as either a yeast or mold AND can grow in saturated salt solutions
hortaea werneckii (tinea nigra)
enlarged infected RBCs with surface invaginations and stipling
schuffners dots seen in plasmodium vivax
CAMP factor
S. agalactiae
more alkaline urine in UTI
proteus UTI
what can give a false positive for lyme
syphilis, mono, SLE, RA, oral spirochete infection
syphilis serologic dx consists of two tests, (1) screening and (2) confirmatory
(1) screening- nontreponemal tests (2) confirmatory- treponemal tests
phthirus pubis dx
visualize the louse
dermatophyte diagnostic tool that digests human tissues and leave fungal components intact
10% KOH prep (potassium hydroxide)
what does a candidiasis cx produce
hyphae, pseudo hyphae, and GERM TUBES
many infected erythrocytes with double or multiple ring stages
plasmodium falciparum
typically seen in upper UTIs and chronic UTIs
K capsular antigen produced by UPEC
UTI with low bacterial numbers in urine
S. saprophyticus
maurers clefts
plasmodium falciparum (these are not as obvious as the schuffners dots seen in p. vivax)
why would you get imaging with a suspected UTI
(1) kids (2) adults w/ recurrent infections (3) hematuria
gas gangrene
tissue bx and gram stain shows muscle necrosis, gram variable rods, and tissue destruction
what is good about the CLED/EMB paddles
they can tell you how many, so you can R/O normal flora
what do you see with a microscopic examination of malessezia furfur (tinea versicolor)
SPAGHETTI AND MEATBALLS (short unbranched hyphae and spherical cells)
PID
clinical criteria + evidence of inflammation (fever, leukocytosis, elevated ESR)
crescent shaped gametocyte
plasmodium falciparum
carbuncles and furuncles
direct exam
malessezia furfur dx
microscopic exam of skin scraping is KOH
venous blood processes with giemsa stain
malaria
chancroid diagnosis requires
identification of Haemophilus ducreyi from genital ulcer or lymph node
struvite stones (made of magnesium ammonium phosphate)
proteus UTI
What if you have a high suspicion of EBV in a preteen but they were negative for heterophile antibodies… how do you dx?
screen for antibodies to virus capsid (anti-VCA antibodies)
or other virus antigens
candidiasis
direct microscopic examination, cx, and serology (but serology sucks)
gonorrhea
nucleic acid amplification (PCR) of cx
viral swarm
HIV
impetigo
clinical presentation
EBV
Monospot- agglutination of horse RBCs reveals heterophile antibodies ***age dependent***
what is the color change in the dermatophyte test medium
red color change indicates alkalinity
scabies dx
apply mineral oil, scrape lesion, visualize microscopically
UTI- culture
50,000 CFU
syphilis serologic screening test
nontreponemal tests (cardiolipin flocculation tests- VDRL, RPR)
syphilis primary and secondary lesions dx
darkfield microscopy or direct immunofluorescence
dermatophytes agar type
sabouraud agar at room temp for 1-3 weeks
young trophozoites and gametocytes in the periphery BUT NO SCHIZONTS
plasmodium falciparum
HHV-6
(1) detection of IgM antibody by EIA (2) PCR amplification- DNA sequence detection by PCR
UTI- gram positive, coagulase negative
S. saprophyticus
what are some of the more reliable methods for identifying for HIV
-
direct nucleic acid tests
- what we usually do w/ donor blood
- screened for HIV antigens P24 or with RNA NAT
- HIV antibody detecting rapid tests- we hope this will replace standard screening
UTI- organism is isolated from normally sterile areas such as blood and CSF, as well as areas with mixed flora like vagina and skin
S. agalactiae
spaghetti and meatballs
malessezia furfur aka tinea versicolor (cutaneous fungi)
plasmodium vivax dx
via giemsa stain
a few enlarged infected RBCs with schuffner dots
UTI- swarming on culture agar **except CLED**
proteus UTI
trichomonas vaginalis
(1) wet mount exam- commonly used (2) cx is more sensitive (3) monoclonal antibodies (4) DNA probe test
basket and band shaped trophozoites and rosette shaped schizonts
plasmodium malariae
UTI- UA microscopy
2-5+ WBCs or 15 bacteria per HPF
syphilis serologic confirmatory test
treponemal tests (specific antibody tests- FTA ABS, MHA TP)
HSV
(1) ballooning pathology and presence of enlarged and fused cells on a tzanck smear of sample from lesion (2)FA assay for viral antigens (3) rapid antibody test
the infective stage of a dermatophyte disease is called ____ and can be visualized how?
called arthroconidium (spore) and can be visualized microscopically with KOH wet mount
tinea nigra (hortaea werneckii) dx
KOH and microscopy
syphilis diagnosis tests can be performed on ___ and ___
serum and lesions
Parvovirus B19
detection of anti B19 antibody
type of candidiasis agar
chromagar
UTI- gram positive cocci
S. agalactiae
with dermatophytes, what can be visualized in dead keratinized tissue
hyphae and arthroconidia
Measles
Presence of multinucleated giant cells on fluorescent antibody test from swab of pharynx, nasal, and buccaneers mucosa
what do you see with a microscopic examination of candidiasis
yeast cells, large G cells, pseudo hyphae, true hyphae, BIG molds
criteria for bacterial vaginosis… has to have 3
(1) homogeneous quality of secretions (2) clue cells (3) release of fishy amine odor when KOH is added (4) vaginal pH over 4.5 (5) presence of curved G- or G variable rods
UTI- alpha and beta hemolysis
UPEC E. coli
lyme disease
clinical findings
serology
ELISA plus western blot (if EIA is positive)
CLED/EMG- what does EMG select for
G- bacteria (kills G+ with bile salts
cellulitis
just tx empirically b/c cx rarely IDs agent
HIV screening
2 step approach:
1st- EIA (shows anti-HIV antibodies)
2nd- western blot (confirms antibodies)
***does not show new infections so not use for blood donation***
UTI- aka Group B streptococcus
S. agalactiae
gray-white colonies with a narrow zone of beta hemolyisis
S. agalactiae
VZV
clinical findings (rash and fever)
what extra tests do kids with a suspected UTI get
cx and imaging
novobiocin resistance
S. saprophyticus- how you differentiate from other staph
chagas disease dx
(1) trypomastigotes seen in acute phase on blood smear
(2) amastigotes seen in bx in chronic case
(3) serology
(4) PCR- the best
what extra tests do men with a suspected UTI get
cx and prostate exam
dermatophyte that is not flurorescent
trychophytan
folliculitis that is not being cured by empiric abx
gram stain (r/o G- or MRSA)
CLED/EMG- what does CLED select for
bacteria that ferment lactose (both G+ and G-)
chlamydia
***isolation of cell cx is the gold standard***
BUT
nucleic acid probes are 95% sensitive
(more so than cx)
RMSF dx
clinical sxs- do not delay on tx, needs to start within first 5 days + direct immunofluorescence
