exam 2 lab and lab images

you conduct a 3% KOH test on a bacteria. What type of bacteria would result in string formation?

negative bacteria

what will happen to negative bacteria when you do a 3% KOH test?

there will be string formation

what will happen to positive bacteria when you do a 3% KOH test?

no string formation

what are the different stains used in microbiology for bacteria?

1. simple stain

2. differential stain

3. negative stain

what are the 2 most important differential staining in diagnostic microbiology?

1. gram stain

2. acid-fast stain for mycobacteria

why would we not want to wave the slide in the air to hasten drying when preparing a mixed smear?

will cause formation of infectious aerosols

why do we not want to overheat our slide when preparing a fixed smear?

will cause distortion of the bacterial morphology

what is the longest the decolorizer should remain on the slide for?

should not exceed 15 seconds

what are common mistakes performed when making a gram stain?

1. overheating

2. over-decolorizing

3. false positive cocci due to thick smear

4. not knowing that gram-positive cells if aged or damaged can appear pink

what does a sample submission for lab diagnosis tell?

what test you are requesting

what is the most common agar used when testing yeast?

sabauround agar but can also use blood agar

what organism do you have if your pathogen appears "peanut or footprint" shaped?

malassezia

what organism do you have if your pathogen appears as a "round football" shape?

candida

what is the common mounting medium used to examine fungi already growing on a laboratory medium?

lactophenol cotton blue (LPCB)

what organism do you have if your pathogen appears "cigar" shaped?

macrocondida

what is the most common tapeworm of dogs and cats?

Dipylidium caninum

what is the appearance of dipylidium caninum?

proglottids are shaped like cucumber seed or rice grains

what do we identify in the fecal examination of tapeworm infections>

gravid proglottids or eggs being passed with feces

what is the most important trematode of ruminants?

fasciola hepatica

what helminth are referred to as "roundworms"?

nematodes

what helminth are considered "hookworms"?

nematodes

what is the fecal floatation technique principle based on?

the specific gravity of the floatation media

what are the different solutions that can be used for fecal floatations?

1. zinc sulfate

2. sodium nitrate

3. sugar and salt solutions

in a fecal floatation what is going to the top of the tube?

eggs, oocysts, cysts, and larvae

what technique recovers more parasitic stages from a fecal sample?

fecal floataton

centrifugation recovers ________ times as many eggs over other passive techniques

3-5 times

what is passive floatation poor at identifying?

floating whipworms, missing 2/3 of all whipworm infections

describe an adult tapeworm

a helminth comprised of proglottids, flattened dorso-ventrally, absorb nutrients since they have no "true gut"

dipyldium caninum egg packet

identify this image

adult paragonimus kellicoti

identify this image

what distinguishing features allows adult Ancylostoma caninum to be identified easily?

hookworms are considered nematodes so they will appear round and have a true gut; they will also have a large buccal cavity that contain teeth and cutting plates

what is the fecal wet mount used to detect?

motile, feeding protozoa stages, but some non-motile resistant cyst stages may also be observed

what is the disadvantage to the fecal wet mount test?

since small amount of feces used, it will have low sensitivity

when would we use saline in a fecal wet mount test?

examine both trophozoites and cysts of amoeba and flagellates

what are the advantages to using the wet mount diagnostic technique?

1. do not need as much feces

2. quick and easy

3. inexpensive

why is fresh feces less than one hour old used to perform saline wet mount?

to be able to see motile trophozoite stage

what is the appearance of the nucleus of entamoeba on the stained fecal slide?

circular with nucleus in center "bullseye"

what is the appearance of flagellates motile stage of giardia?

smiley faced

what is the appearance of flagellates of motile stage of tritrichomonas?

pear shaped

what is the appearance of flagellates of trypanosomes?

squiggle; much smaller than your blood cell

what is the appearance of balantidium coli cyst?

kidney bean shaped macronucleus

what is the appearance of balantidium trophozoite stage?

confetti like appearance staining pink with nucleus staining darker

what is the appearance of eimeria?

hard-boiled egg cut in half; nucleus defined in center and large cytoplasm

what is the appearance of toxoplasma?

nucleus less defined and cell wall is very thick; will not see a cytoplasms and will be more circular

do toxoplasma and eimera share morphology?

no

what characteristics are used to differentiate between the development stages of ticks?

larvae have 6 legs and no genital pore while adult and nymph have 8 legs

what is the morphology of a hard tick?

1. dorsal mouth part

2. smooth body surface

3. possess scutum

what is the morphology of a soft tick?

1. ventral mouth part (not visible)

2. wrinkly body

3. lack of scutum

sarcoptes spp.

what type of mite is shown?

demodex spp.

what type of mite is shown?

otodectes spp.

what type of mite is shown?

what are whipworms?

trichuris trichiuria

what are tapeworms?

diplydium caninum

what are hookworms?

ancylostoma duodenale

what are roundworms?

toxocara canis

what ectoparasite are we referring to when we say "malophaga"?

biting lice

what ectoparasite are we referring to when we say "Ixodiae"?

hard-shell tick

what ectoparasite are we referring to when we say "anopleura"?

sucking lice

what ectoparasite are we referring to when we say "argasidae"?

soft-shell tick

toxocara canis

what ectoparasite is seen in this image?

ancylostoma

what ectoparasite is seen in this image?

trichurus

what ectoparasite is seen in this image?

malophaga

what ectoparasite is seen in this image?

ixodidae

what ectoparasite is seen in this image?

anopleura

what ectoparasite is seen in this image?

argasidae

what ectoparasite is seen in this image?

mites and ticks

what ectoparasites are considered arachnids?

flies, fleas, and lice

what ectoparasites are considered insects?

mallophaga

what is the name of chewing/biting lice?

anoplura

what is the name of sucking lice?

sticktight flea

what is the common name for Echidnophaga

gallinacea?

Echidnophaga gallinacea

what is this ectoparasite?

oriental rat flea

what is the common name for Xenopsylla cheopis?

Xenopsylla cheopis

what is the ectoparasite?

cat and dog flea

what is the common name for Ctenocephalides

felis and C. canis?

Ctenocephalides felis and C. canis

what is this ectoparasite?