Unit 3 Flashcards
What is the name of the group of bacteria that are gram-positive rods often referred to as club-shaped or V & L forms when viewed in a gram stain?
Corynebacterium
What is the major virulence factor associated with corynebacterium diphtheriae?
Diphtheria toxin
A young girl is brought to her physician by her mother, who says the child has been very sluggish with a fever of 38C (100.5F)for a week. The mother noticed that the child’s tonsils were red and that the previous day the back of her throat turned a gray color and looked to have a gray membrane on it. What disease should the physician suspect?
Diphtheria
What organisms displays Babes-Ernst granules on a gram stain?
Corynebacterium diphtheria
What media does corynebacterium diphtheria grow on?
All of the above
*sheep blood agar (SBA)
*Loeffler
*Cystine-tellurite blood
What test is performed to determine if corynebacterium diphtheria is a toxigenic stain of an organism?
Elek test
What corynebacterium species is commonly associated with hospitalized immunocompromised patients?
C. Jeikeium
What is one of the most frequently isolated, clinically significant corynebacteria associated with UTIs?
C. Urealyticum.
All of the following species of Acranbacterium are clinically significant, except
A. Urealyticum
What is the colony morphology of A. Haemolyticum on SBA?
A narrow zone of B-hemolysis and a black opaque dot is seen when the colony is scraped away
What organisms are describe are partially acid fast and diphtheroid gram-positive rods with traces of branching on a gram stain?
Rhodococcus equi
What organism is a member of the human oropharyngeal biota but has been isolated from people with endocarditis?
Rothia dentocariosa
What organism is responsible for spontaneous abortion and stillborn neonates, and can cause meningitis with a fatality rate approaching 50% is newborn?
Listeria monocytogenes
Several people from a picnic came down with GI disturbance, and public health officials suspected a case of food poisoning. The food was cultured, and after 24 hours of incubation the hot dogs yield growth on SBA on small, round, smooth gram-positive coccobacilli. Mortality medium was inoculated and an umbrella pattern of motility was observed at room temperature. What organism was isolated as the cause of illness?
Listeria monocytogenes
Erysipelothrix rhisopathiae produces all t h following diseases except
Meningitis
One of the foremost at a pig farm notices purple sores on one of his workers. The worker has not been feeling well for the past 2 weeks, so the foreman sends him to the physician. The physician takes scrapings from the lesions and sends them to the laboratory for a culture. The gram stain shows 3+ thin, gram-positive rods that have filaments. The culture plates were examined the next day and revealed nonhemolytic, pinpoint, transparent colonies. What is the most likely pathogen?
Erysipelothrix rhusiopathiae
What is the name of the bacterium that plays an important role in the health of the female vaginal tract, protecting it against pathogens?
Lactobacillus
All of the following are general characteristics of the genus Bacillus, except
Cocci
What is the name of the Bacillus sp. that causes anthrax in cattle?
B. Anthracis
What is the name of the organism that, before being identified as an important cause of infections is immunocompromised patients, was considered a common laboratory containment?
Bacillus subtilis
The three proteins that make up the anthrax toxin include all the following except
Cellular factor
How is anthrax spread in animals?
Eating plants contaminated with the spores
What form of anthrax is found amount animal workers and has been called woolsorter disease?
Inhalation
Which of the following would be considered a diphtheroid ? `
Corynebacterium sp.
The presence of gram-variable bacilli on the surface of epithelial cells collected from the vaginal mucosa indicates
Bacterial vaginosis
What disease is considered a complication of any from of anthrax (cutaneous, GI or inhalation?
Meningitis
What bacteria’s morphology is described as large, square-ended, gram-positive or gram-variable rods found singly on in in chains?
Bacillus anthracis
What bacterium produces colonies that are nonhemolytic, large, gray, and flat with an irregular margin on SBA?
Bacillus anthracis
All of the following tests should be performed by sentinel laboratories to rule out the possibility of Bacillus anthracis from an isolate except
Glucose fermentation
What are the confirmatory tests performed at a state laboratory for Bacillus anthracis?
Cell wall polysaccharide end a capsule antigen
What antibiotic, in 2000, was approved by US food and drug administration (FDA) for postexposure inhalation anthrax?
Ciprofloxacin
What Bacillus sp. is a relatively common cause of food poisoning and opportunistic infection in susceptible hosts?
Bacillus cereus
What other gram-positive rod is similar to bacillus anthracis morphologically and metabolically?`
B. Cereus
Which of the following is true about Nocardia spp.??
All of the above
* the organisms grow on strand are nonselective media
*growth may take a week or more
*infections occur in immunocompromised patients
All of the following are commonly encounter Nocardia spp. except
N. Transvalensis
What is the name of the iron-chelating compound by Nocardia spp?
Nocobactin
What is the name of the Nocardia sp. that most frequently causes a cutaneous infection? `
N. Brasíliensis
How can Nocardia spp. be presumptively identified?
Filamentous, branching organisms with a carbolfuchsin acid-fast stain with a weak acid decolonizer but not a kinyoun acid fast stain
What is it that although Nocardia spp. grow on most common nonselective laboratory media, many are missed when the cultures are read?
These organisms require 3-6 days to grow
Why is it important to differentiate infection with Nocardia spp. in pulmonary infections?/
All of the above
*antifungal agents do not kill organisms
*these organisms are resistant to penicillin
*these organisms are susceptible to sulfonamides
What is the name of the genus of organisms that are primarily Saprophytic and resemble aerobic actinomycetes with the morphology and disease they cause?
Streptomyces
What is the name of the genus whose members are called nocardioforms?
Gordonia
Colonies of Bacillus anthracis are described as
Medusa heads