Deck 38: Neisseria and Moraxella Catarrhalis

Question 1

An advantage of all molecular assays is:

A)the ability to test for C.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.

Answer 1

A
Molecular assays have replaced old enzyme-linked immunosorbent assay (ELISA)systems for the rapid diagnosis of N.gonorrhoeae.Amplified assays are more sensitive than the nonamplified assay and are suitable for large-scale screening programs,but none are admissible as evidence in medicolegal cases.N.gonorrhoeae DNA can be found in a specimen for up to 3 weeks after successful treatment;therefore,amplified molecular assays should not be used to assess test of cure.

Question 2

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

Answer 2

D
The organism described is M.catarrhalis,which has a smooth "hockey puck" consistency,meaning the colony may be moved intact over the surface of agar.For this organism,all sugars listed are negative.

Question 3

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)N.gonorrhoeae.
B)Neisseria meningitidis.
C)Neisseria lactamica.
D)M.catarrhalis.

Answer 3

A
N.gonorrhoeae is glucose-positive but maltose- and lactose-negative.N.meningitidis is glucose- and maltose-positive and lactose-negative,and N.lactamica is positive for glucose,maltose,and lactose.M.catarrhalis is negative for all three.

Question 4

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 5

M.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 6

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

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

Question 7

Gonococci require which of the following nutrients for growth?

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

Question 8

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

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

Question 9

The differentiation of the similar M.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)carbohydrate utilization testing.

Question 10

Blood cultures collected for the recovery of N.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 11

M.catarrhalis can be described as a:

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

Question 12

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 13

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

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

Question 14

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 35°C instead of 25°C.
D)No discrepancy is present.N.sicca does not grow on MTM agar.

Question 15

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 16

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

A)M.catarrhalis
B)Chlamydia trachomatis
C)N.gonorrhoeae
D)N.mucosa

Question 17

Which statement is true regarding the pathogenesis of N.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 18

M.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 19

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

Question 20

Organisms belonging to the genus Neisseria are:

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

Question 21

The second most commonly reported sexually transmitted infection in the United States,according to the CDC,is:

A)M.catarrhalis.
B)N.gonorrhoeae.
C)N.meningitidis.
D)HIV.

Question 22

N.gonorrhoeae is spread by:

A)person-to-person nosocomial spread by respiratory droplets.
B)person-to-person spread by sexual contact.
C)from infected mother to newborn during birth.
D)B and C only.