Deck 39: Neisseria and Moraxella Catarrhalis

Question 1

Organisms belonging to the genus Neisseria are:

A) gram-positive diplococci.
B) gram-negative diplococci.
C) gram-negative coccobacilli.
D) gram-negative bacilli.

Answer 1

B
Species of the genus Neisseria discussed in Chapter 40 and Moraxella catarrhalis are all oxidase-positive, gram-negative diplococci that do not elongate when exposed to subinhibitory concentrations of penicillin.

Question 2

The gram-negative coccus that can be described as oxidase-positive, glucose-negative, maltose-negative, sucrose-negative, lactose-negative, and DNase-positive is:

A) Neisseria meningitidis.
B) Moraxella catarrhalis.
C) N. cinerea.
D) N. gonorrhoeae.

Answer 2

B
All these characteristics can be used to describe M.catarrhalis.

Question 3

The differentiation of the similar Moraxella catarrhalis and Neisseria can be best accomplished by:

A) examination of Gram stain of the colony.
B) vancomycin susceptibility testing.
C) the oxidase test.
D) glucose utilization testing.

Answer 3

D
M.catarrhalis may be differentiated from Neisseria on the basis of its growth on blood agar at 22° C and nutrient agar at 35° C, the reduction of nitrate to nitrite, its inability to utilize carbohydrates, and its production of deoxyribonuclease (DNase).M.catarrhalis is the only member of this group of organisms that hydrolyzes deoxyribonucleic acid (DNA).

Question 4

An organism isolated from a sputum sample that has a "hockey puck" consistency would have which of the following biochemical profiles?

A) Glucose-positive, maltose-positive, and lactose-positive
B) Glucose-positive, maltose-positive, and lactose-negative
C) Glucose-positive, maltose-negative, and lactose-negative
D) Glucose-negative, maltose-negative, and lactose-negative

Question 5

Blood cultures collected for the recovery of Neisseria gonorrhoeae or N.meningitidis require:

A) no special methods.
B) more than 0.025% sodium polyanethol sulfonate (SPS).
C) transfer from Vacutainer tubes to culture broth within 1 hour of collection.
D) less than 0.025% SPS.

Question 6

An endocervical swab was collected from a 26-year-old woman with a purulent discharge.The Gram stain revealed the following: · Many white blood cells (WBCs)
· Moderate gram-negative diplococci
· Moderate gram-negative coccobacilli
· Few yeast
Based on these findings, what would be the next course of action?

A) Report the isolation of Neisseria gonorrhoeae.
B) Work up the yeast.
C) Report the Gram stain, and follow up with culture.
D) Request a new specimen; this one is contaminated.

Question 7

Which one of the following statements is true regarding antimicrobial therapy and susceptibility testing?

A) Cephalosporins and macrolides are ineffective against Moraxella catarrhalis.
B) Resistance to quinolones is emerging in strains of Neisseria gonorrhoeae.
C) Most Neisseria spp. are resistant to penicillin.
D) Most strains of N. meningitidis are resistant to penicillin.

Question 8

Moraxella catarrhalis may be differentiated from gonococci and meningococci on the basis of its:

A) growth on blood agar at 35° C.
B) growth on nutrient agar at 22° C.
C) reduction of nitrite to nitrate.
D) production of DNase.

Question 9

Moraxella catarrhalis can be described as a:

A) gram-positive diplococcus.
B) gram-negative diplococcus.
C) gram-negative coccobacillus.
D) gram-negative bacillus.

Question 10

Which statement is true regarding the pathogenesis of Neisseria cinerea?

A) N. cinerea is a leading cause of fatal bacterial meningitis.
B) Virulence factors include pili, capsule formation, and endotoxin.
C) Disseminated intravascular coagulation (DIC) and thrombocytopenia are complications of infection.
D) N. cinerea is commonly encountered as a contaminant in clinical specimens.

Question 11

Moraxella catarrhalis may be described as:

A) oxidase-positive.
B) a glucose utilizer.
C) a major cause of venereal disease.
D) often carrying an antiphagocytic capsule.

Question 12

Which two organisms should be used to determine the validity of the nitrate reduction test?

A) Neisseria gonorrhoeae and N. lactamica
B) N. mucosa and Moraxella catarrhalis
C) N. lactamica and M. catarrhalis
D) N. sicca and N. subflava

Question 13

The bacterial species that can be described as oxidase-positive, glucose-positive, maltose-positive, sucrose-negative, lactose-negative, and a major cause of bacterial meningitis is:

A) Neisseria meningitidis.
B) N. lactamica.
C) N. flavescens.
D) N. gonorrhoeae.

Question 14

Gram-negative diplococci are isolated from a genital specimen and yield the following results: · Glucose: positive
· Maltose: negative
· Lactose: negative
The organism can be identified as:

A) Neisseria gonorrhoeae.
B) N. meningitidis.
C) N. lactamica.
D) Moraxella catarrhalis.

Question 15

The determination of carbohydrate utilization patterns for the differentiation of Neisseria spp.and M.catarrhalis is best performed by:

A) incubation of inoculated cysteine trypticase soy agar (CTA) with 1% dextrose, maltose, lactose, and sucrose for 48 to 72 hours.
B) oxidative-fermentative (OF) medium with dextrose, maltose, lactose, and sucrose.
C) heavy inoculation of buffered, low-peptone substrate with dextrose, maltose, lactose, and sucrose.
D) carbohydrate testing strips.

Question 16

An advantage of all molecular assays is:

A) The ability to test for Chlamydia trachomatis from the same specimen at the same time
B) The ability to use these tests for assessing the successfulness of treatment
C) Their role as evidence in medicolegal cases
D) The ability to detect the capsular antigen in body fluids

Question 17

A gram-negative diplococcus grew on 5% sheep blood agar and chocolate agar, had scant growth on MacConkey agar, and had no growth on modified Thayer-Martin (MTM)agar.The organism was identified as N.sicca.Which one of the following statements explains the discrepancy of the results obtained on the MTM agar?

A) The medium was most likely expired.
B) The organism was most likely incorrectly transported.
C) The organism was most likely incubated at 35º C instead of 25º C.
D) No discrepancy is present. N. sicca does not grow on MTM agar.

Question 18

MTM, Martin-Lewis (ML), and New York City (NYC)media were all developed for the selective isolation of which organism?

A) Moraxella catarrhalis
B) Neisseria meningitidis
C) N. gonorrhoeae
D) N. mucosa

Question 19

The JEMBEC transport system for Neisseria spp.provides an atmosphere with increased _________ to keep the organism viable during transport.

A) hydrogen (H2)
B) carbon dioxide (CO2)
C) nitrogen (N2)
D) nitrate (NO3)

Question 20

Gonococci require which of the following nutrients for growth?

A) Arginine
B) Hypoxanthine
C) Uracil
D) IsoVitaleX