aerobic gram positive rods (non spore formers)

corynebacterium, listeria, lactobacillus, erysipelothrix, gardnerella nocardia, streptomyces)

corynebacterial on a gram stain are described as

club shaped or picket fence pattern

the diphtheria toxin is the major virulence factor associated with

corynebacterium diphtheriae

the tox gene is able to

block protein synthesis in eukaryotic cells

which fragment of the diphtheria toxin is responsible for the cytotoxicity and is also known as the catalytic domain

fragment A

which fragment of the diphtheria toxin binds to receptors on human cells and is also known as the transmembrane domain

fragment B

which form of corynebacterium is more common and more serious

respiratory (pharyngeal) diphtheria

cutaneous diphtheria is often recovered along with ___ as secondary infections

s. pyogenes and s. aureus

all of the following are specialty selective media for corynebacterium diphtheriae except

regan lowe agar

c. diphtheriae microscopic morphology is also often referred to as

chinese letters

which organism has metachromatic granules observed on growth from loeffler’s medium stained with methylene blue

corynebacterium diphtheriae

to speciate c. diphtheria, the ___ test can confirm toxin production

ELEK

a positive ELEK test for toxin production is indicated by

arch of identity

which corynebacterium species is usually found on inanimate objects in hospitals

c. jeikeium

which corynebacterium species is highly urease positive

c. urealyticum

which corynebacterium is a urinary tract pathogen

c. urealyticum

which organism is associated with cold foods like cheese and deli meat

listeria monocytogenes

listeriosis is uncommon but a serious infection that primarily affects

pregnant women and neonates

l. monocytogenes has a microscopically observed ____ motility

tumbling

L. monocytogenes is similar to

group B strep (s. agalactiae)

L. monocytogenes is catalase ___, meanwhile group B strep is catalase __

positive, negative

L. monocytogenes grows in what conditions

cold environments and high concentrations of salt

the CAMP test for L. monocytogenes has a ____ hemolysis pattern

block

which organism has an umbrella motility

listeria monocytogenes

which organism plays a significant role in maintaining the acidic environment needed for healthy vaginal flora

lactobacillus

which organism is carried in the digestive tract of turkeys and swine

erysipelothrix rhusiopathiae

which organism is highly resistant to food preservation practices such as salting, smoking, and pickling

erysipelothrix rhusiopathiae

which group of people are most at risk for getting infected with erysipelothrix rhusiopathiae

fishermen, butchers, veterinarians

erysipeloid symptoms

lesions on hands or fingers, the infected area is painful and swollen

erysipelothrix is H2S ___

positive

which organism has a ‘bottle brush’ growth appearance on gelatin stab culture

erysipelothrix rhusiopathiae

gardnerella vaginalis is associated with what disease

bacterial vaginosis (BV)

the raise in vaginal pH greater than 4.5 is due to the ___ in lactobacillus population

reduction

the presence of clue cells is highly indicative of

g. vaginalis

the best medium for growth of gardnerella vaginalis is

HBT agar and V agar

gardnerella vaginalis is hippurate hydrolysis ___

positive

all of the following are branching gram positive aerobes except

gardnerella vaginalis

the colony and microscopic morphology of this organism resembles fungi

nocardia

nocardia is ___ acid fast

partially

nocardia is susceptible to

sulfonamides

nocardia is resistant to

penicillin

80% of lung infections is caused by

nocardia asteroides

80% of skin infections are caused by

nocardia brasiliensis

a cutaneous infection caused by N. brasiliensis is also referred to as

actinomycotic mycetomas

nocardia cutaneous infections may contain pigmented pus that contains

sulfur granuels

which branching organism has a wrinkled, dry and adherent colony morphology

nocardia

nocardia can grow well on all the selective media except

MTM

under dissecting microscopes, nocardia colonies may reveal the presence of ___

aerial hyphae

nocardia spp is modified acid fast ___

positive

streptomyces is ___ acid fast

non

which organism is associated with head and neck mycetoma

streptomyces spp.

which organism has a ‘spider like’ microcolony appearance

streptomyces

actinomyces is ___ acid fast

non

actinomycosis causes abscesses in the ___

jaw

which organism has a ‘molar tooth’ looking colony

actinomyces

actinomyces is H2S ___

positive

how can nocardia spp be presumptively identified

Filamentous, branching organisms with a carbolfuchsin acid-fast stain with a weak acid decolorizer, but not a Kinyoun acid-fast stain

what corynebacterium species is commonly associated with hospitalized immunocompromised patients

c. jeikeium

what organism displays babes-ernst granules on a gram stain

corynebacterium diphtheriae

true or false: growth for nocardia spp. may take a week or more

true

what test is performed to determine if corynebacterium diphtheriae is a toxigenic strain of an organism

elek test

all of the following are commonly encountered nocardia spp. except

n. transvalensis

how do corynebacterium species often appear on gram stained smears

pleomorphic, gram-positive, club-shaped bacilli that appear in palisades or in V and L formations

biochemical tests performed on a gram-positive bacillus were consistent with corynebacterium diphtheriae. which definitive test should the laboratory scientist perform next?

perform an elek test to determine whether the organism produces exotoxin

why is diphtheria uncommon in the united states

routine use of an effective human vaccine

true infections with nondiphtheria corynebacterium spp., such as c. jeikeium or c. striatum, often occur in immunocompronised patients or patients who have had which of the following

insertion of hardware or prosthetic devices

when recovered from urine samples, which test can help differentiate which clinically significant corynebacterium spp.

urease; c. urealyticum

A newborn female patient becomes febrile and will not feed for about an hour after birth. A gram-positive rod is recovered from blood cultures from the newborn. The isolate has the following characteristics:

Weakly β-hemolytic on SBA

Gram-positive bacilli, no spores observed

Catalase positive

Hydrogen sulfide negative

Motile at room temperature

What is the most likely identity of the isolate?

listeria monocytogenes

A commercial fisherman with red sores on his hands was seen by his physician. Biopsy and culture of one of the lesions grew an organism with the following characteristics:

Nonhemolytic on SBA

Gram-positive bacilli, no spores observed

Catalase negative

Hydrogen sulfide production positive

Growth in gelatin resembled a test-tube brush

What is the most likely identification?

erysipelothrix rhusiopathiae

A 42-year-old male patient from Guatemala cut his bare feet on thorns while walking. A subcutaneous abscess developed, and when the patient is seen by a physician, his foot is swollen. When the physician presses the wound, purulence is expressed along with some soft, white granules. A filamentous organism that is partially acid fast is recovered from the granules. This is most likely an __________ mycetoma caused by __________.

actinomycotic; nocardia brasiliensis