Exam 4 Flashcards
Define Actinomycetes as an organism: colony morphology gram stain motility defining characteristics
branching, GPR, non motile, has filamentous form, partially acid fast (mycolic acid) , aerobic, beaded
What are the genera of interest in the Actinomycetes order
NOCARDIA, Rhodococcus, Gordonia, Tskuamurella
what environment are Nocardia found in
soil and water, decompose plant material
What is the common source of infection of Nocardia
traumatic injury or inhalation
What are the species of Nocardia that are clinically relevant, what body sites are they each found in?
Nocardia abscessus - any body site
Nocardia brasiliensis- only skin
Nocardia asteriodes
Describe the colony morphology of Nocardia species? and the gram stain?
GPR, beaded appearance, variably acid fast
morphology-rough like a fungus
Which Nocardia species is most often pathogenic, what illness does it cause
N. asteroides, causes skin infection, myecetomas, subcutaneous, abcesses, cellulitis
What patients tend to get Nocardia infections
transplant, immunodeficient with pulmonary disease, IV drug users
How should Nocardia be transported, processed and collected
no special requirements
What specimen type could we find Nocardia on
fluid and swabs, sinus tract drainage, skin biopsy
If you find Nocardia in a respiratory specimen, what is the next step
must question if its real, need more proof, could be simple contamination. not aa critical result
What are the other less concerning Actinomycetes species
Rhodococcus
Gordonia
Tsuakurella
All usually skin
What extra steps can be taken to ID actinomycetes in a biopsy or drainage specimen
need to look for granules, washed in saline, on gram stain, will see yellow to orange kidney shaped club structures, need to determine if strain is bacterial or fungal
What special selective media do we need to grow actinomycetes in vitro
SDA sabouraud dextrose agar
BHI brain and heart infusion agar
—takes long time to grow
BCYE- much faster, best option
What environmental conditions will let Actinomycetes grow
aerobic, 35C, 2-3 weeks ambient air
What do Actinomycetes look like in an acid fast stain?
And on a gram stain?
red, long thin fiber looking
beaded GP, tiny, BRANCHING
What biochem results for Nocardia
acid fast- pos lysozyme resistance- pos urea hydrolysis- pos nitrate reduction- pos/ neg anaerobic- neg
Key words to Nocardia growth on SG, medium, and Choc
SB- golden
medium0 rough and buff, orange color slimey gross
Choc-snow white, pinpoint
What catalase result does Nocardia give
positive
What are the important catalase negative Gram positive rods, non branching
lactobacillus, arcanobacterium, gardnerella, erysipelothrix
How is Listeria transmitted? What environment is it found in?
direct contact with animals, soil, vegetation
usually contaminated food: meat, veggies, dairy
possible to transmit mother to fetus- no deli meats causes meningitis in infants
What population is most susceptible to Listeria illness
pregnant women, neonates, elderly and immunocompromised
How do you grow Listeria in vitro
needs lots of AAs, vitamins, more fastidious
BHI- Brain, heart infusion
sometimes TSB
What biochemical results are staples for Listeria? motility? hemolysis?
**Tumbling motility, umbrella, at room temp
**CAMP + block shape
catalase +
BE +
narrow Beta hemolytic
What specimen/ body sites can we find Listeria in
blood or CSF
What Corynebacterium species do we care most about and why?
Transmission?
C. diptheriae- not normal flora always pathogenic, toxins very lethal to people
respiratory, pus, fomites, direct
What part of the body does C diphtheria infect?
upper respiratory, causes gray pseudomembrane in back of throat
What patients tend to be affected by C diptheriae
immonocompromised, IV drug use, alcoholics
How are these cornybacterium species transmitted? C. diptheria C. urealyticum C. striatum C. jeikium C. ulcerans C. pseudotuberculosis C. pseudodiptheriticum
C. diptheria- repiratory droplets, skin lesion pus, fomites, nosocomial
C. urealyticum- wound infection, UTI
C. striatum- catheter, sterile body parts
C. jeikium- catheters,
C. ulcerans-animals, cattle, skin infections or pneumonia
C. pseudotuberculosis- zoonotic, limited to LUNGS
C. psuedodiphtheriticum- sepsis, pneumonia, lung absesses, sterile body site
What do corynebacterium look like on gram stains
GPR club shape, non branching, no spores, Chinese letters, V or L shape
What plates do corynebacterium grow on
SB and Choc not Mac
must be selective and differential when from respiratory specimen
What special media do we use for Corynebacterium? What results indicate the more important one?
Cysetine Tellurite-
Tinsdale
black brown halo on both media- C. diptheriae
What are the biochemical results for C diptheria
esculin - non motile urease - nitrate + catalase + Tinsdale + H2S + hemolysis Y
Distinguish biochemical tests for C. ulcerans C. pseudotuberculosis C. striatum C. pheudodipthericum C. Jeikeium
C. ulcerans: urease +, reverse arrow CAMP, Tinsdale +
C. pseudotuberculosis: urease +, reverse arrow CAMP, Tinsdale +
C. striatum: neg everything, pos nitrite
C. pheudodipthericum: + urease, + nitrate, neg all others
C. Jeikeium: neg everything but lipophilic
What Cornyebacterium are just normal flora, which ones are actually concerning
normal: C. amycolatum, jeikeium, pseudodiptheriticum, striatum,
abnormal:
C. psuedotuberculosis: zoonotic,
C. ulcerans: ulcers and pharyngitis,
C. urealyticum: UTIs,
C. diptheria: lethal upper respiratory
What test is used to ID diptheroids vs normal flora? which organism falls in this category
Rhodococcus- GPR with traces of branching
SBA-pink colonies
ID based on gram stain and colony pigmentation
How can we ID true pathogen C. diptheriae
must prove toxin production, lipis help enhance growth
Elek plate test
must see precipitin line radiating outwards
What biochem test help find C. urealyticum
urease +, nitrate -
What are the general characteristics of Bacillus species
What O2 conditions do they need to live
sporulating, GPR, aerobic or facultative anaerobe, mesophilic, mostly beta, motile except anthrax
catalase +
spore forming
What do Bacillus species look like on a gram stain?
GPR in stacking formation
can sometimes show endospores, look like long beaded necklace
boxcar formation
in singles, pairs or serpentine chains
What group of bacillus is anthrax in? What other species are in this group
Cereus group
bacillus cereus
What body sites can Bacillus anthracis be found in
skin, blood, CSF, respiratory
Where can bacillus anthracis be found in the US?
in livestock workers, travelers or terrorism
What does Bacillus anthracis look like on a BAP? motility?
comet tail, medusa head morphology, gamma hemolytic, non motile, gooey and can peel off plate
What population does bacillus anthracis mostly affect?
wild and domestic animals, animal vaccines are distributed for it
humans can get it from trauma, inhalation or ingestion
What are the 3 main virulence factors that Bacillus anthracis has
lethal toxin
Edema toxin-inflammation and swelling of tissue, confuses immune system
Protective antigen- protein that help LT and ET entry
What are the 4 disease manifestations of anthrax and what body site are they each associated with. Which is the most common
cutaneous-wound-most common
gastrointestinal- stool
inhalation- sputum
injection- biopsy
How do each of these infections gain entry into the body and brief symptoms and severity. B anthracis cutaneous gastrointestinal inhalation injection
cutaneous- broken skin, black eschar
gastrointestinal- ingestion, N,D,V more fatal
inhalation- wool sorter’s, highest mortality
injection- skin popping, IV drugs, sepsis, NO black eschars
What are the following bacillus species associated with
B.cereus
B. Thuringiensis
B. Subtilis and others
B.cereus-rice, food poisoning, V, D
B. Thuringiensis- also foodborne, used as pesticides
B. subtilis and others- usually opportunistic environmental contamination
What samples are collected from cutaneous anthrax
from under eschar
pulmonary- biopsy and pleural fluid
GI- blood cultures, peritoneal fluid
What is the heat shock method
used for bacillus anthracis, hated to kill most except the endospores, can be plated and stained this way
T or F B. anthracis is not very contagious
T is needs a high dose to become infectious
What media will Bacillus species grow on? Where won’t it grow
BAP, CHOC
not CNA nor MAC
What are the most distinguishing features of bacillus anthrax vs other species
only one that is gamma non motile
What are the biochemicals for bacillus anthracis
Catalase +
Non-motile
S to penicillin
What do Bacillus cereus look like on SB agar? And a gram stain?
beta- brown, motile, frosted glass on gram stain
List the Bacillus anthracis ID testing in the correct order and when to report it out
GS: GPR
Colony: ground glass, non pigmented, gamma, no growth on MAC or EMB
Biochems: Catalase +, Non motile
could be B. anthracis, send to reference lab
Explain S&S testing for bacillus food poisoning
serology testing kit for patient feces or food products
find PA, LF or EF proteins/ toxins
indirect hemmagglutination
Name the 4 species of interest that are catalase negative, non branching, GPR
arcanobacterium
erysipelothrix
gardenella
lactobacillus
What are erysipelothrix infections assocaited with
animal and livestock workers- zoonotic
infection from puncture wound
What are the 3 types of infection that can result from Erysipelothrix rhusiopathiae
localized skin- hands and fingers, purple red zone
diffuse cutaneous-
bacteremia and endiocarditis-
What populations tend to become infected with E. rhysiopathiae
worldwide in animals like mammals, birds and fish
T or F if you salt, pickle or smoke meat you can get rid of E. rhusopathiae
False it is resistant to all of these
What are the biochem tests for Erysipelothrix? Colony morphology?
catalase - H2S +*** non motile VP- Urease- Esculin- large and rough can start as gamma then to alpha
What does Erysipelothrix look like in a gram stain
GPR thin, long filaments , V shape, short chains, slender
What body sites can Erysipelothrix be found in
tissue biopsy or aspirates from skin lesion
What diseases and groups are Arcanobacterium associated with
animal pathogens, could cause tissue abcesses, ulcers, septicemia in immunocompromised pts
What do Arcanobacterium look like on a BA plate?
And on a gram stain?
friable, narrow beta, dry or mucoid, gray
looks like beta strep
GS- GPR slightly curved
What is liquefaction of gelatin used to distinguish and what do the results mean
Arcanobacterium haemolyticum- negative
Trueperella pyogenes- positive
What organism can cause a false + on lancefield testing
Archanobacterium, tells you group G strep
What does Arcanobacterium look like on CAMP, explain the reaction
reverse arrowhead when with S. aureus
B lysine in S. aureus inhibits phospholipase D in Arcanobacterium haemolyticum
What do Gardenella vaginalis look like on a gram stain
small, pleomorphic, gram variable because they have thinner peptidoglycan layer
What does Gardnerella look like on BA and HBT
BA-small and pinpoint, Gamma, thin
HBT- Beta hemolysis
How is bacterial vaginosis confirmed to be gardenella
clue cells, low numbers of lactobacillus, high Gardnerella
What are the biochemical tests for Gardnerella vaginalis
catalase -
oxidase -
S to SPS
S to alpha strep
What disease is associated with Lactobacillus
non they are beneficial, can cause infection only in immunocompromised patients
What organism does lactobacillus help control?
G. vaginalis
What does lactobacillus look like on BAP
pinpoint, alpha, looks like strep,
rough
What biochemical testing is there for lactobacillus
catalase-
thats it, ID with this plus morphology and gram stain
