question
A microbiologist does a Gram stain on a CSF. She sees intracellular and extracellular gram-negative diplococci. What is the most likely organism?
answer
N. meningitidis
question
A young adult goes to the emergency department complaining of headache, dizziness, stiff neck, and purpura with a petechial skin rash. What two tests should the physician immediately perform?
answer
Blood and cerebrospinal fluid (CSF) culture
question
Gonococcal infections occur primarily in all the following sites, except
answer
uterus
question
How are Neisseria gonorrhoeae infections transmitted?
answer
Sexual contact
question
How is Neisseria meningitidis most commonly spread?
answer
Respiratory droplets
question
How should a specimen for Neisseria gonorrhoeae culture be transported to the laboratory?
answer
Placed in Amies with charcoal transport system and transported to the laboratory immediately
question
If a Gram stain of urethral discharge from a male has more than four polymorphonuclear leukocytes per field but no bacteria, this is suggestive of what condition?
answer
Nongonococcal urethritis
question
If a female is symptomatic, what are the most common symptoms of Neisseria gonorrhoeae infection?
answer
Cervical discharge and dysuria
question
If a male is infected with Neisseria gonorrhoeae, what would be the results of a Gram stain of purulent urethral discharge reveal?
answer
Many polymorphonuclear white blood cells, some with gram-negative intracellular diplococci, and extracellular gram-negative diplococci
question
In a CTA carbohydrate test, a gram-negative diplococcus produces acid only from glucose and maltose. You should suspect
answer
Neisseria meningitidis.
question
Nonpathogenic commensal Neisseria spp. include all the following, except
answer
Neisseria meningitidis.
question
The symptoms of meningococcal meningitis include all of the following, except
answer
backache.
question
The virulence factors for Neisseria spp. include all the following, except
answer
exotoxin.
question
To which category do most Neisseria spp. belong?
answer
Capnophilic
question
Typically, all Neisseria spp. are all of the following, except
answer
motile
question
Under what conditions should inoculated plates for Neisseria gonorrhoeae culture be incubated?
answer
35° C and 3% to 5% carbon dioxide
question
What disease is most commonly associated with newborns passing through a birth canal infected with Neisseria gonorrhoeae?
answer
Ophthalmia neonatorum
question
What organism is a commensal of the upper respiratory tract and has become an opportunistic pathogen causing upper and lower respiratory tract infections in otherwise healthy children and the older adults?
answer
Moraxella catarrhalis
question
Why do Thayer-Martin and Martin-Lewis media have antimicrobial agents added?
answer
To prevent overgrowth of normal biota
question
What type of swab should be used for a Neisseria gonorrhoeae culture?
answer
Dacron
question
A microbiologist is reading a sputum culture and notices that there is no growth on the sheep blood and MacConkey (MAC) agar plates, but there is heavy growth on the chocolate plate. The colonies on the plate are translucent, moist, smooth, and convex, with a mousy odor. What is the most likely identification of the organism?
answer
Haemophilus influenzae
question
A microbiologist is reading a sputum culture and notices tiny, translucent colonies growing closely around a β-hemolytic colony on sheep blood agar (SBA). The colonies are growing in the area where the blood has been hemolyzed. What is the probable identity of the organism that is growing closely to the β-hemolytic organism, and why are they growing in the hemolyzed area?
answer
Haemophilus spp., because they need the factor V in this area
question
A technician is working the night shift and receives a CSF specimen on an infant. The technician makes a Gram stain of the spinal fluid, then reads the smear under the microscope. The report the technician sends to the physician reads as follows: "gram-negative bacillus, small and pleomorphic." What bacteria are being implied as the infecting agent?
answer
Haemophilus influenzae
question
All of the following are characteristics of Haemophilus spp., except
answer
gram-positive cocci.
question
How is pertussis spread?
answer
Respiratory droplet
question
This organism is described as glistening, silver, and resembling a mercury droplet on media supplemented with horse blood.
answer
Bordetella pertussis
question
What agar is used to isolate Bordetella pertussis?
answer
Bordet-Gengou
question
What are the names of the two diseases caused by Legionella species?
answer
Legionnaires' disease and Pontiac fever
question
What is the most frequently isolated Pasteurella species?
answer
Pasteurella multocida
question
What is the name of the organism that causes tularemia, which can be contracted from rabbits?
answer
Francisella tularensis
question
What is the specimen of choice for Bordetella pertussis?
answer
Nasopharyngeal swabs
question
What medium is used to isolate Legionella?
answer
Buffered charcoal yeast extract (BCYE)
question
What organism is likely to cause an infection after a cat bite?
answer
Pasteurella spp.
question
What organism produces a community-acquired pneumonia, with symptoms different than a Streptococcus pneumoniae infection, leading to the designation of atypical pneumonia?
answer
Legionella pneumophila
question
Which one of the virulence factors associated with Haemophilus spp. plays the most significant role in the invasiveness of the organism?
answer
Capsule
question
Which species are associated with infections in humans?
answer
-Haemophilus aegyptius
-Haemophilus ducreyi
-Haemophilus influenzae
-Haemophilus ducreyi
-Haemophilus influenzae
question
Which species of Haemophilus requires both X and V factors?
answer
H. influenzae
question
A fastidious gram negative rod is isolated from a human bite wound. It is growing on the SBA and CHOC agars with small, yellow colonies that are pitting the agar. A chlorine bleach-like odor is detected from the agar. What is this organism?
answer
Eikenella corrodens
question
What is the causative agent of undulant fever?
answer
Brucella
question
The following are all characteristics of the HACEK group of organisms except for:
answer
Gram positive rod
question
A chocolate agar plate incubated at 42° C from a stool exhibits colonies that are nonhemolytic, moist, "runny looking," and spreading. The Gram stain shows tiny gram-negative rods with some S-shapes and seagull-wing shapes. What is growing on the plate?
answer
Campylobacter
question
All of the following are biochemical characteristics of Vibrio spp., except
answer
oxidase negative.
question
How is Helicobacter pylori presumptively identified?
answer
A rapid urease test done on a gastric biopsy
question
How is cholera treated?
answer
Copious amounts of intravenous fluids
question
Most Vibrio sp. are generally halophilic. However, which one can also grow in an environment with 0% sodium chloride?
answer
V. cholerae
question
Most infections caused by Vibrio cholerae are associated with
answer
ingestion of undercooked seafood.
question
What disease manifests in acute cases as a severe gastroenteritis, accompanied by vomiting followed by diarrheic stools that are described as rice water and occur 10 to 30 times a day?
answer
Cholera
question
What environment is Aeromonas spp. most commonly found in?
answer
Fresh water
question
What is the name of the organism that is responsible for "summer diarrhea" in Japan?
answer
Vibrio parahaemolyticus
question
What is the name of the organism that is strongly associated with gastric, peptic, and duodenal ulcers, as well as gastrointestinal carcinoma?
answer
Helicobacter pylori
question
What two biochemical tests help distinguish Aeromonas spp. from other enterics?
answer
Oxidase and indole
question
What type of an atmosphere do campylobacters require for growth?
answer
Microaerophilic and capnophilic
question
Which of the following is a curved, gram-negative rod that grows on thiosulfate citrate bile salts sucrose (TCBS) agar?
answer
Vibrio
question
Aeromonads have been implicated in all of the following diseases, except
answer
pneumonia.
question
All of the following characteristics describe the genus Plesiomonas, except
answer
oxidase negative.
question
What organism may play a role in Guillain-Barré syndrome (GBS)?
answer
Campylobacter
question
What temperature is an optimal growth temperature for Campylobacter jejuni?
answer
42° C
question
When collecting specimens that may contain Campylobacter spp. bacteria, what transport medium should they be placed in, if a delay in transport is possible?
answer
Cary-Blair
question
Which of the following Vibrio species is most likely to be recovered from extraintestinal tract infections, e.g., septicemia and necrotizing fasciitis?
answer
V. vulnificus
question
What does the term halophilic refer to?
answer
Organism requires increased NaCL for growth