MICRO BACKUP 8/10 340PM Flashcards
5 species with capsules:
-mucoid, antigenic/serotype
-Cryptococcus neoformans
-Strep/Kleb pneumo
-H.influ, N.meningitis
5 nonmotile
Flagella etc
Mono/Amphi/Peri…
Lopho…
-Kleb, Shigella
-Bacillus anthracis
-Corneybacterium
-L.mono at 35C
Flagella etc
Mono/Amphi/Peri…flagellus at one,both,all around
Lopho…tuft of flagella at a polar end
Describe hemolysis:
alpha prime:
alpha:
beta:
gamma:
Describe hemolysis:
alpha prime: aplha surrounded by beta
alpha: incomplete, green
beta: complete, transparent
gamma: no hemolysis
QC:
dry heat oven:
autoclave/wet:
QC:
dry heat oven: B.subtilis
autoclave/wet: B.stearothermophilus
-dry=shorter bacillus
-wet=longer bacillus
7 sterilization methods…
1 most effective…
1 used if media can’t be heated…
6 sterilization methods…
-1 most effective…autoclave
-1 used if media can’t be heated…filtration
-boiling
-dry heat/flame
-fractionalization
-glutarldehyde: cold sterilization
-ethylene oxide gas
3 antiseptics: tissue
3 disinfectants: surfaces
-one best for viruses,spores,TB,fungi
antiseptics:
-alcohol, iodine, hydrogen peroxide
disinfectants:
-chlorine best for viruses, spores
-phenol
-quaternary ammonium
Stains:
ingredients, what it stains
-Gram:
-Wright:
-Kinyoun/ZielNeelson
-Fluorochrome
Stains:
ingredients, what it stains
-Gram:
1.)crystal violet stains thick peptidoglycan wall with teichoic acid of GP, purple-blue
2.)iodine/mordant: fixes CV in GP
3.)acetone: washes CV out of GN
4.)safrannin: counterstain for GN, pink-red
-Wright:
methanol, asure B, eosin
rbc/wbc/plts
-Kinyoun/ZielNeelson:
carbol fuchin, acid alcohol, methylene blue
mycobacterium
-Fluorochrome:
rhodamine, acid alcohol, permanganate
mycobaterium
Most abundant NF in throat…
Most common pathogen in throat…
NF: alpha heme strep (viridans)
pathogen: S.pyogenes
Nasopharygeal swab for these 3…
Throat swab for this…
Nasopharygeal: upper respiratory
H.influ, N.mening, B.pertusis
Throat swab:
Strep pyogenes
Sputum processing
-not saliva
-gram stain first
-<10 epi, >25PMNs/lpf best
3 GPC in clusters aerobic that are catalase+
4 GPC in chains/pairs aerobic catase -
3 GPC in clusters aerobic that are catalase+
-Staph, CNS (epi,sapro), micrococcus
4 GPC in chains/pairs aerobic catase -
-Strep(A pyogens,B agalactiae)
-enterococcus, group D
Differentiate CNS S.epi from S.sapro with…
-both cat+, coag neg
S.epi…skin
S.sapro..UTI
Differentiate S.epi from S.sapro with…
S.epi…suspectible to Novobiocin
S.sapro..resistant to Novobiocin
Grp… strep susceptible to…
How many units…
Grp…strep resistant to…
GrpA:
Bacitracin
0.02-0.04
GrpB: resistant to Bacitracin
Differentitate Grp A from GrpB strep
-both cat neg
Grp A..
-sensitive to
-1 test pos for
Grp B…
-resistant to
-2 tests are pos for
Group A sensitive to Bacitracin
-PYR pos
Group B resistant to Bacitracin
-CAMP, hippurate +
Both enterococcus and Grp D hydrolyze…
Differentiate these two with…
-enterococcus
-Grp D
both hydrolyze esculin
-enterococcus grows in NaCl
-Grp D doesn’t
What diff GPC aerobic from aerobic GNDC
GPC…
GNDC…
oxidase: purple
-drop reagent on colony
-rub colony filter paper, drop reagent
-rub colony on filter with reagent
*but do not use nichrome loop it will give false pos
GPC oxidase neg
GNDC oxidase pos
Alpha heme strep…
what diff between the two…
S.pneumo…
Viridians
S.pneumo:
-bile soluble, optochin susceptible
viridans:
-optochin resistant
Sugar fermentation…
N.gonn..
N.mening..
N.lac..
Moraxella..
-two test pos for
N.gonn=glucose
N.mening=glucose, maltose
N.lac=glucose,maltose, lactose
Moraxella=none
-DNase pos
-Butyrate esterase pos
2 genera GNDC, oxidase pos…
how to diff..
Neiserra, Moraxella
sugars
Best media for gonococci/meningcocci…
what is main agar, 3 antibiotics, additonal
Modified is Thayer Martin plus
-trimethoprim lactate(inhibits proteus swaming)
Thayer Martin
-enriched choc agar
-colistin, nystatin, vancomycin inhibit other bacteria/fungi
-incubate with increase CO2
Martin Lewis: better at inhibiting yeat than TM
NYC
GC-LECT
JEMBEC: transport/growth N.gonn
Chocolate agar:
-enriched, blood lysed supplies X,V
-increased CO2
-Haemopholis/Neisseria
Two genera that caues pelvic inflammatory disease
N.gonn
-no cotton or calcium alginate swab
Chylamydia trachomatis
-no wooden shaft
In addition to bile salts, each of the 3 have an additional selective agent…
HE:
XLD:
SS:
HE: bromothymol blue, acid fuchsin
XLD: deoxycholate
SS: brilliant green
3 General GN selective media:
-selects for, with, if diff/what diff with/for
EMB:
MAC:
SMAC:
TSI H2S indicators, sugars, reading
Eosin Methylene Blue(EMB)
-selects for enteric GNR with dyes
-eosin and methylene blue dye inhibit GP
-diff LF green-black to purple (E.coli has green metallic sheen)
MacConkey:
-selects for enteric GN by inhibiting GP with bile salts and crystal violet dye
-diff LF(pink)
Sorbital MacConkey:
-selects for E.coli 0157 with sorbitol, 0157 doesn’t ferment sorbitol and is colorless
Triple sugar agar:
-mostly lactose/sucrose, some glucose
-butt=glucose, slant=sucrose/lactose
-yellow acid, pink=alkalineH2S
TSI indicatiors:
-ferric amm. citrate/sulfate
(not the same is H2S in SS media, Na thiosulfate)
-Salmonella is H2S pos
Agar: melts at 100, solidifies 45
4 media for GP:
SBA
CNA
PEA
SSA
Sheep blood agar:
-selects for nonfastidious, enriched w/blood
-diff with hemolysis/sheep blood
Colistin nalidixic acid:
-selects for GP by inhibiting GN with colistin/nalidixic acid
-sheep blood
Phenylethyl alcohol agar:
-selects for GPC by inhibiting enteric GNR with phenylethyl alcohol
Selective Strep Agar:
-selects for Grp A with antibiotics to suppress NF of throat
-does not different between A or B
-sheep blood
3 Media for Corynebacterium diptheriae…
which two are diff…what reagent…color…
which one is enrichment…enhances these 2
Corynebacterium diptheriae media
*tellurite inhibits NF, C.diph reduce it making it gray-black
Cysteine-tellurite blood agar
-diff w/tellurite, black
Tindale agar:
-diff w/tellurite, gray to black, brown halo
Loeffler
-enrichment for metachromatic granules and pleomorphism
2 media for Vibrio:
1 select/diff with…color…
Thiosulfate citrate bile salts(TCBS)
-diff with sucrose (cholerae is yellow)
Alkaline peptone water(APW)
-enrichment
2 media for Bordetella pertusis:
Best choice is….
Bordetella pertusis
Regan Lowe:
-charcoal agar enriched w/blooed etc
Bordet-Gengou:
-potato glycerol enriched w/blood
-cough plate, mercury droplets colonies
CIN agar for…colony appears…
BCYE for…has… …
HBT Tween for….
CIN: YerSINia, bulls eye colorless halo
*Aero,Plesi, shigelloides
BCYE:
-buffered charcoal yeast extract
-yeast/cysteine enhance Legionella
-charcoal absorbs toxic stuff
HBT Tween: G.vaginalis
-human blood bilayer
-selects for G.vag
-diff w/hemolysis
5 Gram positive rods aerobic, acronym..
1 random gram positive that is cocoid then 24hrs a rod…
BCLEN
-Bacillus
-Corynebacterium
-Listeria monocytogenes
-Erysipelothrix (test tube brush,occupational)
-Nocardia
Rhodococcus equi: coccus to rod 24hrs
BCLEN: GPR aerobic..
Bacillus…shape, motility
Anthracis
spore forming, bamboo pole
string of pearls, Medusa head
nonmotile
cerus:
-food poisoning
BCLEN: GPR aerobic:
Corynebacterium is a gram…,….
diff from L.mono with… and ….
test for toxin…
NF diptheroid…
Hospital acquired diptheroid
Gram positve rod, nonmotile
-chinese letters,picket fence
-pallisade, club shaped
-BabeErnst, metachromatic granules
diff with L.mono:
C.diph is nonmotile/salicin neg
C.diph has toxin, detected with Elek test
NF diphtheroid: pseudodipheriticum
Hospital acquired: jeikeium
BCLEN: GPR aerobic
Gram postive to gram variable coccobaccilus
Catalase pos
hippurate/camp pos
Listeria mono
tumbling motility 25C, cold for months
food poisoning, meningitis newborns
catalase/salicin/motility pos
*looks like GrpB Strep
-but is catalase pos
BCLEN: GPR aerobic
Both Corynebacterium and Listeria can be gram postive rods aerobic, how to differentiate
Listeria is motile and salicin pos
Corynebacterium is nonmotile and salicin neg
BCLEN: GPR aerobic
GPR aerobic
Fine branching/filaments, beaded
sulfur, urease pos
cannot grow with antibiotics
Nocardia
skin=brasil
lung=asteroides
GNR cause of whooping cough…
prefered media…
alternate medium…
species that is urease/oxidase pos…
Bordetella preferss Regan Lowe,
-will grow on Bordet-gengou
bronchiseptica is urease/oxidase pos
4 GNR fastidious ass with animals
-cat scratch, trench
-cat/dog, musty, bipolar
-goat/cow, undulant fever
-rabbit, tularemia
4 GNR fastidious ass with animals
-cat scratch, trench: Bartonella
-cat/dog, musty, bipolar: Pasteurella mul
-goat/cow, undulant fever: Brucella
-rabbit, tularemia: Franciella
GNR fastidious ass with goat/cow, undulant fever…
-needs CO2, inhibited by thionin
-not on fuchin
-doens’t make H2S
GNR fastidious ass with goat/cow, undulant fever…Brucella
-needs CO2, inhibited by thionin: arbortus
-not on fuchin: suis
-doens’t make H2S: melitensis
GNR fastidious…
-Pontiact fever, AC, BCYE:
-Best on Regan Lowe…two kinds….
-Whooping cough:
-urease/oxidase pos
-Pontiac fever, AC, BCYE: Legionella
-Best on regan lowe: Bordetella
-whooping cough: pertusis
-urease/oxidase pos:bronchisepta
Legionella best medium, second best/color
BCYE
-needs cysteine
Feeley Gorman iron cysteine, brown
2 GNR fastidious, slender, curved
microaerophillic…
how much of each gas
Campy: gull winged
Heli
85% N, 10% CO2, 5% O
3 GNR fastidious, faculative, GI
-rice water stools, TCBS,
string test pos reagent?
-aquatic, doesn’t grow TCBS
-now enterobacteria, doesn’t grow on TCBS
3 GNR fastidious, faculative, GI
Vibrio chloreae
-rice water stools, TCBS,
string test pos(0.5% Na deoxycholate)
Aeromonas
-aquatic, doesn’t grow TCBS
Pleisiomonas
-now enterobacteria, doesn’t grow on TCBS
GNR fastidious, slender, curved
microaerophillic…
-seagulls, 42C, darting corkskrew motility, most common cause of bacterial diarrhea
-doesn’t like 42C, stomach/peptic ulcer, urea breath test
GNR fastidious, slender, curved
microaerophillic…
Campy jejuni
-seagulls, 42C, darting corkskrew motility, most common cause of bacterial diarrhea:
Heli pylori
-doesn’t like 42C, stomach/peptic ulcer, urea breath test
-Skirrow agar
GNCB, pleomorphic
enriched chocolate, fastidious, filamentous
needs X and/or V, satellitism
-upper resp/nasopharyn swab, capsule, needs X,V
-pink eye, needs V
-NF needs mostly V
-Not NF, STD/chancroid, school of fish, needs X
Haemophilus:
GNCB, pleomorphic
chocolate, fastidious, filamentous
needs X and/or V, satellitism
-staph supplies V(NAD), hemoylysis releases X(hemin from agar)
influenze:
-upper resp/nasopharyn swab, capsule, needs X,V
aegypticus:
-pink eye, needs V
parainflu,hae,parahae:
-NF needs mostly V
ducreyi:
-Not NF, STD/chancroid, school of fish, needs X
HACEK: GNCB, Capnophillic, oral flora, endocarditis
Haemophilus, Aggre/actino, Cardio,
Eikinella, Kingella
3 main GNR nonfermenters
-oxidase pos, swimmers ear, grape
-NF skin
-cystic fibrosis/immunocomp, ammonia
3 main GNR nonfermenters
Pseudomonas aeruginosa:
-oxidase pos, swimmers ear, grape
Acine-tobacter
-NF skin
Stenotrophomonas maltophilia:
-cystic fibrosis/immunocomp, ammonia
other nonfermenting…
Burk, Elizabeth,Morax, Alcali
Nonfermentation media, oxidizers….
can see acid production due to…
indicator is…
how may tubes…etc
OF oxidation fermentation
-need oxygen, low peptone media
-bromthymol blue indicator
-2 tubes: one open, one covered w/oil
5 GN intracellular, bacterial like wall, arthropod vectors
-grows in egg yolk sacs, ticks, typhus pox
-2 with morulae in WBC, ticks
-scrub/bush typhus, mites
Rikettsae
5 GN intracellular, bacterial like wall, arthropod vectors
Rikettsia:
-grows in egg yolk sacs, ticks, typhus pox
Ehrlicha/Anaplasma:
-2 with morulae in WBC, ticks
Orienta:
-scrub/bush typhus, mites
Enterobacteriacea are nonfastidous and…
gram…
oxidase…
ferment…
reduce…
gram negative
oxidase neg
ferment glucose
reduce nitrate
IMViC is…
1st 4 pos is color..
last one pos color…
Indole, Methyl red, VP all are red/pink pos
Citrate is blue
IMViC acrynon and genus:
++–
–++
PEE ++–
-Proteus, E.Coli, Edwardsella
KES –++
-Klebsiella, Enterobacter, Serratia
3 aminos in Decarboxylase test/acrynm…
How many tubes…
Decarboxy: LAO (lysine, arginine, orthinine)
4 tubes (one for each, ctrl)
PD(phenylaline deaminase) and urease acronym
PD(deaminase)+ urease=PPM
-Proteus
-Providencia
-Morganella
Urea pos acronym
Urea PUNCH
proteus
ureaplasma
nocardia
Cryto neo
Heli
Nitrate reduction:
-initial pos looks like…
-add zinc pos looks like…
initial red, zinc clear is pos
ONPG tests…
detects…
which organism is ONPG pos
slow LF
detects beta galactosidase
citrobacter
DNAse pos is…
two DNAse pos
clearing around colony 0.1N HCl
m.catt, serretia
Antigen serotyping:
O=
H=
K=
O=sOmatic, both salmonella, shigella
H=flah-gella, only salmonella is motile
K=Kapsule, S.typhi
Acceptable anaerobic..
Unacceptable…
-bile, blood, BM, BF
-aspirates
-tissue,wound
unacceptable:
-swabs
-sputum, washings,gastric
-voided, catheterized urine
-feces
Anaerobic gas conditions…
80-90 N
5-10 CO2
5 H
No oxygen!!!
Anaerobic cocci:
1 GPC
1 GNC
Anaerobic
GPC: peptococcus
GNC: Veilonella (red fluoresence)
Acronym for anaerobic GPR
Anaerobic GPR
CLAP
-Clostridium(spores)
-Lacto(vagina pH)
-Actinomyces israelli(lumpy jaw)
-Propionibacterium(acne,NF)
2 Clostridium that have oval subterminal spores…
1 has tennis racket terminal spores..
1 has round terminal spores…
2 Clostridium that have oval subterminal spores…
-botulinum
-difficile
1 has tennis racket terminal spores..
-tetani
1 has round terminal spores…
-ramosum
4 GNR anaerobic
-Bacteriodes fragilis (resistant to penicillan)
-Fuso
-Prevo, Porphy
Genera that is acid fast, high lipid content,
need 5-10% CO2 at 35C
id off growth, morph, temp, biochem, light rxn, pigment
Myco-bacteria
Mycobaceteria temp, gas req
NALC:
NaOH:
35C
5-10CO2
NALC: liquify
NaOH: digest/decontaminate
3 Spirochetes
-Borrelia
*burgdorferi: most common, ixodes tick,
lyme/bulls eye/erythema chronicum migran
*recurrentis: relapsing fever
-Treponema pallidum: syphillis, darkfield/silver
-Leptospira interrogans: Weils, zoonotic/urine
-Fletchers medium
2 media for mycobateria…
-best to view microscopically/clear
3 stains…
cold, hot
Mycobacteria
2 media:
-Middlebrook 7H11: clear
-M=mycobacterium, Middlebrook, microscopically
-Lowenstein Jensen: green
*read uncovered, if growth then read uncovered
3 stains:
-Kinyoun: cold
-Ziehl Neelsoen: hot
both carbol fuschin, acid alcohol, MB
-Fluorochrome: more sensitive
*auramine rhodamine, acid alcohol,
potassium permaganate, acridine orange
How to diff M.tb from M.bovis
M.tb niacin/nitrate pos
M.bovis neg
Mycobacterium Leprae:
to be diagnostic needs to be from..
lepra cells are….
alternate name…
tissue fluid
macrophages w/acid fast bacilli
Hansens disease
Tween 80 for what mycobacterium…
neg=
pos=
Mycobacterium test that splits phenolphthalein from triK phenolphthalein-sulfate in 2-3days…
Tween 80 M.kansasii
neg=amber
pos=pink
aryl-sulf-atase test
Most common bacterial STD, pelvic inflammatory disease
obligate intracellular parasite
Chamydia trachomatis
Two free living with no cell wall, not bacteria
use antisera and test inhibition of growth
Mycoplasma: fried egg, walking/atypical pneumonia
Ureaplasma:
Loeffler: C.diph
Lowenstein Jensen: mycobacteria
Regan Lowe: B.pertusus
Loeffler: C.diph
-granules, pleomorphism
Lowenstein Jensen: mycobacteria
Regan Lowe: B.pertusus
Parasite:
-how many collect, w/in how many days, every.. …
-Process w/in: liquid, soft, formed…
-clean/dry: no urine/h20/barium
-3 specimens w/in 10 days, every other day
-liquid 30min
-soft 1hr
-formed 24hrs
Parasite stains used for
-Trichorme:
-Wrights/Giesma
-Acid fast:
-Iron Hematoxylin:
-saline:
-Iodine:
Parasite stains:
-Trichorme: nuclear red/purple blue back
-Wrights/Giesma
-Acid fast: spores
-Iron Hematoxylin: microfilarial sheath
-saline: motility
-Iodine: nuclear
Preservation:
-2 for cysts,eggs, larvae
-2 for trophs
-1 for trophs, cysts for fresh stool
Preservation:
-2 for cysts,eggs, larvae:
-fridge, formalin, MIF
-2 for trophs:
-PVA, SAF
-1 for trophs, cysts for fresh stool:
-Schaudinns
Sedimentation:
contains these two, four layers
ethylacetate: removes fat/oil but fat/debris stay in separate layer
formalin: preserves
sediment=parasites
Concentration:
-FES: ingredients, what 4 layers
-Zinc sulfate flotation: sg
Concentration:
FES: ingredients, what 4 layers
-Formalin: preserves
-Ethyl acetate: removes oil/fat
-S: sedimentation (parasites)
Zinc sulfate flotation: sg
-sg 1.18, parasites float to top
-miss operculated large
4 Genera of Protozoa
Ameba, Flagellates, Ciliates, Sporozoa
Trichomonas:
-which one has undulating membrane 1/2 the length, trasmission
-which one has undulating membrane full lenth, transmission
vaginalis: 1/2, sexual
hominis: full, feces
Trypanosoma:
-West…
-East…
-vector, sickness
Both Tse Tse fly, trypomastigote blood
Gambiense:
-West african sleeping sickness
Rhodesiense
-East african sleeping sickness
T.cruzi:
-vector
-can be transmitted by…
-disease called…
-amastigote in…
-trypomastigote in…
T.cruzi:
-vector: reduvid bug
-can be transmitted by…blood transfusion
-disease called…Chagas
-amastigote in…heart
-trypomastigote in…blood
Leismania
-Kala Azar…
-Old…
-New…
Leismania
-Kala Azar…dovani
-Old…tropic
-New…braziliensis
6 sporozoa genus
Plasmodium, Babesia
Crytosporidium, Cyclospora, Isospora
Toxoplasma
2 Plasmodium that infect young/large RBCs, schuffners dots
-which one has resistance in duffy neg
vivax: duffy neg resistance
ovale
Plasmodium with Hmg S/G6PD resistance, banana shaped, multiple rings
falciparum
Sporozoan with four maltese cross ring forms, from deer tick
Babesia microti
6 Nematodes
Enterobius: Pinworm
Trichuris: whipworm
Strongyloides: threadworm
Nectar/ancyclo: hookworms
Ascaris: large intestine roundworm
Microfilaria:
Which 2 spread by mosquito, elephantitis, blood:
Which 2 spread by fly
-calabar/eye swelling
-blindness, nodule
Microfilaria:
Which 2 spread by mosquito, elephantitis, blood: Wucheria, Brugia
Which 2 spread by fly: loa loa, onchocerca
-loa loa: calabar swelling,eye
-onchocerca: blindness, nodule
Sheath, nuclei:
3 have sheaths:
-1 doesn’t have in tip:
-1 has 2:
-1 goes to tip:
1 doesn’t have sheath or nuclei:
Sheath, nuclei:
3 have sheaths:
-1 doesn’t have in tip: wucheria
-1 has 2: Brugia
-1 goes to tip: Loa loa
1 doesn’t have sheath or nuclei: onchocerca
2 tissue nematodes:
-one with sushi, granuloma:
-one with pigs, encysted larve, muscle biopsy:
2 tissue nematodes:
-one with sushi, granuloma:
Aniskasis
-one with pigs, encysted larve, muscle biopsy
Trichinella spiralis
Trematodes:
3 intestinal/liver:
1 blood/bladder:
1 lung:
Trematodes:
3 intestinal/liver:
-clonorchis: chinese liver
-Fascioloa hepatica: sheep liver
-F.buski: giant GI
1 blood/bladder:
-Shistosoma
1 lung:
Paragonimus westmanii
Chinese Liver fluke…
Chinese vase/Lung fluke:
Giant intesting fluke:
Sheep liver fluke:
Chinese Liver fluke…Clonorchis
Chinese vase/Lung fluke: Paragonimus
Giant intesting fluke: F.buski
Sheep liver fluke: Fasciola hepatica
Blood fluke, Shistosomes spines and location in veins…
-Sml, lateral, intestine veins:
-lrg, lateral, intestine veins:
-lrg terminal, bladder veins:
Blood fluke, Shistosomes spines and location in veins…
-Sml, lateral, intestine veins: japonicum
-lrg, lateral, intestine veins: mansoni
-lrg terminal, bladder veins: haematobium
5 Cestodes/tapeworms:
ribbon like, proglottids, segmented
Tania
Hymenolepsis
D.latum (only operculated)
Echinococcus
D.caninum
Names of diseases:
-cutaneous larva migrans/creeping eruption
-larva currens
-erythema chronicum migrans
-visceral larva migrans:
Names of diseases:
Strongyloides:
-larva currens
Borellia burgdoferi/Lyme;
-erythema chronicum migrans
Ancyclostoma braziliense
-cutaneous larva migrans/creeping eruption:
toxocara canis/cat:
-visceral larva migrans
GPR aerobic spore forming, bamboo pole
string of pearls
nonmotile
B,anthracis
Gram positve rod, nonmotile
-chinese letters,picket fence
-pallisade, club shaped
Corynebacterium diphtheria
Phase where bacteria are maturing but not about to divide
Lag
Plasmodium vector…
Babesia vector
Plasm anopheles mosquito
Babesia deer tick
H.nana, Diminuta vector
Flea, beetle
Which fastidious, gram-negative coccobacilli is often associated with trauma after human bites or fights where the skin has been broken by human teeth?
Eikenella corrodens is a member of the usual flora of the oral and bowel cavities. It usually occurs in mixed infections as a result of trauma, especially human bites or “clenched fist wounds”. E. corrodens is also seen in persons with poor oral hygiene, causing adult periodontitis and meningitis.
In addition to Giardi sp, what other intestinal parasite is clinically important in the United States?
a.
Cryptosporidium sp
b.
Cyclospora sp
c.
Isospora sp
d.
Toxoplasma sp
Cryptosporidium sp
The classic ova and parasite diagnostic method is accurate, but technically demanding and time consuming.
Due to the high likelihood of Giardia or Cryptosporidium as the causative parasite, numbers DFA, EIA and ICT assays are available for screening tests.
What is an example of streptococcal group test?
a.
Enzyme immunoassays
b.
Immunofluorescent assays
c.
Particle agglutination
d.
Precipitin tests
Particle agglutination
Streptococcal grouping tests use a form of particle agglutination in which antibodies are bound to the surface of latex beads which bind to the antigen present in a sample to produce a visible clump.
What is a disadvantage of the zinc sulfate flotation method for separating protozoan cysts and helminth eggs in fecal specimens?
Question 177Answer
a.
Some helminth eggs do not concentrate well with this method
b.
The centrifugation times are longer
c.
The preparation is not as clean as the sediment method
d.
There are no disadvantages to the method
Some helminth eggs such as operculated eggs and/or very dense eggs such as unfertilized Ascaris eggs do not concentrate well with the flotation method. Their density causes them to sink instead of float.
A gram-negative rod > 100,000 col/cc is recovered from a midstream urine. The isolate is swarming over the blood plate, produces hydrogen sulfide on TSIA, and hydrolyzes urea, indole negative and ornithine positive. What is the likely organism identification?
Question 176Answer
a.
Morganella morganii
b.
Proteus mirabilis
c.
Proteus penneri
d.
Proteus vulgaris
Proteus mirabilis is a commensal species in the gastrointestinal tract of humans. It is widely disseminated in the environment and recognized as an opportunistic pathogen.
Proteus vulgaris is indole positive and ornithine negative.
Proteus penneri is ornithine negative.
Morganella morganii is indole positive and H2S negative on TSIA.
Which organism needs the X and V factors required for fastidious organisms?
Haemophilus spp. need the X and V factors required for fastidious organisms.
Which organism does not usually cause disease in a host with an intact immune system, but may cause disease in a host with a compromised immune system?
a.
Community acquired infection
b.
Nosocomial infection
c.
Opportunistic pathogen
d.
Spore forming pathogen
Opportunistic pathogen is defined as an organism that does not usually cause disease in a person with an intact immune system, but that can cause disease when the host’s immune system has been compromised by disease or other condition that has damaged or changed the immune status of the host.
Community acquired infection
-less than 48hrs since being in healthcare
Nosocomial infection
-while receiving healthcare, 48hours after admission
What gram positive cocci are most frequently associated with UTIs in young, sexually active females?
Staphylococcus saprophyticus has been associated with UTI’s in young sexually active females. This species adheres more effectively to the epithelial cells lining the urogenital tract than other coagulase-negative staphylococci.
What kind of sample can a parasitic infection be diagnosed through the identification of eggs (ova) or larvae?
a.
Blood sample
b.
Fecal sample
c.
Nail scraping
d.
Urine sample
Fecal sample
The parasites are residing in the intestinal tract. Stool specimens for ova and parasite studies must be preserved or fixed immediately.
What cells do not have a nucleus, or any membrane bound organelles such as mitochondria, and their ribosomes are a smaller size than eukaryotic ribosomes?
Prokaryotes:
Bacterial cells are prokaryotes and are less complex in structure than eukaryotic cells. Prokaryotes, from the Greek “before nucleus”. They lack all membrane-bound organelles.
-DNA is in a single chromosome in a nucleoid region
-peptidoglycan cell wall
Eukaryotes:
-true nucleus
-animal, plant, fungal,parasites
-membrane bound nucleus, organelles, cytoskeleton, larger ribosomes
-have mitrochondria
How is the use of molecular assays to detect antimicrobial resistance genes limited?
a.
Genes are not responsible for most types of antimicrobial resistance
b.
Genes may be present but not expressed; presence of the gene may not reflect resistance
c.
Large numbers of genes are responsible for all clinically important resistance
d.
Researchers have not identified genes for antimicrobial resistance
Genes may be present but not expressed; presence of the gene may not reflect resistance
There is concern about using molecular methods to confirm resistance because of the ability of some bacteria to contain specific resistance genes that may not be expressed. The clinical significance of the presence of the resistance genes in these bacteria is questionable.
A 20-year-old male presents to the Emergency room with heavy urethral discharge that had been present for three days. He has been sexually active with several partners and has used no contraceptives. A culture of the discharge grows a gram-negative diplococci with adjacent sides that are flattened and is oxidase positive. What is the likely organism?
Neisseria gonorrhoeae is a sexually transmitted, oxidase positive, gram negative diplococci that can cause urethral discharge in males and females.
*no cotton and no calcium alginate swabs, inhibit
Thick smear used to..
Thin smear used to…
The thick smear is used to screen a larger volume of blood; the thin smear is used to identify the parasite because the parasites are not as distorted as with the thick smear.
What is the process of destroying pathogenic organisms, but not necessarily all microorganisms or bacterial spores (endospores)?
Question 191Answer
a.
Antisepsis
b.
Disinfection
c.
Filtration
d.
Sterilization
Disinfection:
Disinfection is the process of destroying pathogenic organisms, but not necessarily all microorganisms or bacterial spores (endospores). Physical (moist or dry heat) or chemical (e.g., bleach, phenol, alcohols, aldehydes) means may be used in the process of destroying pathogenic organisms.
Antisepsis:
decreased number of microbes present on skin.
-iodine,alchol,chlorhexidine
Sterilization:
killing/destruction of ALL microbes including spores.
-heat, filtration, oxidation
-dry heat: 171C 1hr
-wet heat/autoclave: steam under pressure 121C 15lb,15min
-filtration: heat sensitive media
A 70-year-old female with a previous knee injury has joint replacement surgery. The surgery goes well, and she is discharged from the hospital to a rehabilitation facility to receive post-operative care and physical therapy. One week later the incision becomes inflamed and begins oozing a discharge. A gram stain of the discharge shows many white blood cells and gram-positive cocci in clusters. The isolate recovered is a cream-yellow beta-hemolytic colony that is catalase and coagulase positive. What is the likely organism?
Staphylococcus aureus is a gram-positive cocci in clusters that generally yields a cream-yellow beta-hemolytic colony that is catalase and coagulase positive. Streptococcus pyogenes and Enterococcus faecalis are gram positive cocci that are catalase negative. Staphylococcus epidermidis is coagulase negative.
Which specific bacteria, parasitic cysts and rare fungal forms contain mycolic acid in their cell wall and retain the basic dye despite acid alcohol rinsing?
Acid fast organisms (containing mycolic acid) resist decolorization by acid alcohol destaining and appear the color of the primary stain.
What do specimens for parasitic identification include?
a.
Hair, nails, stool, urine, and sputum
b.
Hair, stool, urine, bone marrow, and sputum
c.
Stool, urine, blood, sputum, and tissue biopsies
d.
Tissue biopsies, cartilage, hair, nail, and urine
Stool, urine, blood, sputum, tissue biopsies
Specimens for parasite identification come primarily from the intestinal tract, urogenital tract, or prostatic secretions. Specimens can also come from sputum, CSF, or biopsy material from tissues. Malarial parasites can be seen in blood.
Any identification process first depends on correct specimen (stool, urine, blood, sputum, tissue biopsies) collection and adequate fixation.
Which four groups can most bacteria be divided into based on gram stain results?
a.
Gram positive bacilli, gram positive cocci, gram positive tetrads, and gram negative bacilli
b.
Gram positive bacilli, gram negative bacilli, gram positive clusters, and gram negative chains
c.
Gram positive bacilli, gram negative bacilli, gram positive cocci, and gram negative cocci
d.
Gram variable bacilli, gram positive diplococci, gram negative rods, and gram positive cocci
Gram positive bacilli, gram negative bacilli, gram positive cocci, and gram negative cocci
Tetrads, diplococci, clusters, and chains are descriptions of cellular arrangements not basic shapes. Variable indicates an indistinct staining reaction.
When should the concentration of fecal materials be included?
a.
Intestinal formalin
b.
Intestinal ova
c.
Ova and parasite examination
d.
Thick and thin smears
Ova and parasite examination
Concentration procedures allow the visualization of small numbers of parasitic organisms that may be missed if only a direct mount is observed.
Various concentration procedures are used, most often sedimentation or floatation techniques.
What kind of insects belong to the phylum Arthropoda group?
The phylum Arthropoda includes insects, spiders, mites, and ticks. Members of this phylum are a subgroup of parasites and are invertebrates.
What gram negative rod is associated with lobar pneumonia in hospitalized patients?
Klebsiella pneumoniae is a frequent cause of lower respiratory tract infections among hospitalized patients.
What is the etiologic agent in Lyme disease?
Diagnosis of Lyme disease depends on finding antibodies in the serum or spinal fluid. The etiologic agent is the bacterium Borrelia burgdorferi.
A 10-year-old child presents to his primary care physician with a complaint of severe ear pain. The child had been swimming in the lake several days earlier. The culture from the ear grew a gram-negative rod with a grapelike odor. The colonies were flat and spreading with rough edge and a metallic sheen. It was indole negative and oxidase positive. What is the likely organism?
The organism is likely Pseudomonas aeruginosa. Pseudomonas is commonly found in fresh water. P. aeruginosa produce a grape like odor, are oxidase-positive and indole negative.
What concentration of oxygen is required for the growth of obligate anaerobic organisms?
0% oxygen
Obligate anaerobes must be grown in an atmosphere either devoid of oxygen or with significantly reduced oxygen content.
What nutrients in chocolate agar enable organisms to grow on this media but are unable to grow on blood agar?
Hemin (X) and nicotinamide adenine dinucleotide (V) factors
Chocolate agar contains lysed red cells which release hemoglobin, hemin (X) and nicotinamide adenine dinucleotide (V) factors.
What are the most common causes of bacterial conjunctivitis in children?
a.
Haemophilus influenzae andStreptococcus pneumoniae
b.
Herpes simplex and Varicella zoster
c.
Propionibacterium acnes and Alpha-hemolytic streptococci
d.
Staphylococcus epidermidis and Lactobacillus spp.
Haemophilus influenzae and Streptococcus pneumoniae are common causes of bacterial conjunctivitis in children.
Staphylococcus epidermidis, Lactobacillus spp., Propionibacterium acnes and alpha-hemolytic streptococci in small numbers are normal flora of the conjunctival sac.
Herpes simplex and Varicella zoster are viral infections.
pshychophiles:
-0-20C
-cold
mesophilic:
-moderate temp 30-37
-most pathogenic bacteria,
Ecoli, Salmonella
thermophilic:
-thrive in high temp, 50-60C
-not pathogenic cuz can’t grow at body temp
hyperthermophilic:
-80-120C
Incubators
Most pathogens:
35C host temp, 3-5% CO2, humidified
-Can use candle jar for CO2, only white unsented candles
Fungi:
30C
Campylobacter:
42C
Culturing specimens/processing/planting/rejection…
*don’t refrigerate spinal, anaerobic, GC
*no dry swabs
Stool;
-lots of NF
-w/in 2hrs
Urine:
-bladder normally sterile
-clean catch mid stream
-first morning more concentrated
-process in 1hr or fridge 24hrs
-<10 epis
->100,000 sig
Catheter tip/intravenous:
Indicate source of sepsis or infected indwelling arterial/venous catheter
-For optimal culture results, transport specimen to the laboratory within 2 hours
Urethral/cervical/gynecological:
-No wood shaft on Chlamydia
-No cotton/calcium alginate on Neisseria
IUD:
-Sterile container
-Store and transport room temperature, preferably within 8 hours of collection.
-Actinomyces sp
Culturing specimens/processing/planting/rejection…
Blood:
-sterile collection in nutrient broth media b4 fever
-70% alcohol, iodine, alcohol rinse
-1:10 dilution blood to broth
-10ml adults, 5ml kids
-can use ARD for antibiotic removal
Respiratory:
-sputum 1st morning, deep coughing, avoid saliva
-contamination if gram stained shows >10 eips/lpf
-upper respiratory swab for throat culture group A beta strep and culture blood media
Wound/abcess:
-Eswab: 48 hours, refrigerated or ambient
-Sterile cup: 24 hours refrigerated
Tissue:
-Tissue not in formalin
-Sterile screw capped vial, anaerobic culture transport, bacterial culture transport swab with media, or sterile cup
-RT
CSF:
-sterile tubes
-centrifuged if >1ml, 5/10ml best
Microscopic morphology;
Pairs and Clusters:
-S.aureus, CNS
Pairs and Chains:
-Group A,B,C,F,G beta hemolytic strep
-Viridians strep
-Enterococci
Lancet shaped, pairs/chains, halo due to capsule
-S.pneumo
Macroscopic/Colony morph
Staph aureus
-med to lrge, creamy, beta
CNS
-sml-med, no pigment, gamma
Group A,B,C,F,G beta strep
-mostly small gray white, beta
Strep pneumo
-sml, glistening, mucoid, convex, alpha
Viridans strep
-pinpoint, alpha
Enterococcus
-small, gamma
