Micro Haem, Neiss, and Morax Quiz

Which of the following describes Haemophilus influenzae Biotype II?

Primarily causes ear infections and is ornithine negative and indole positive

Older colonies of Moraxella catarrhalis may give this appearance.

wagon-wheel

In the porphyrin test, porphobilinogen is detected by the addition of

Kovacs’ Reagent

All of the following are characteristics of Haemophilus spp., except

oxidase positive.

facultative anaerobes.

catalase positive.

gram-positive cocci.

gram-positive cocci

Gonococcal infections occur primarily in all the following sites, except

uterus

urethra

endocervix

anal canal

uterus

What is the drug of choice for treating a life-threatening illness caused by H. influenzae?

Ceftriaxone

What disease is most commonly associated with newborns passing through a birth canal infected with Neisseria gonorrhoeae?

Ophthalmia neonatorum

What medium will sustain the growth of most Haemophilus spp.?

Chocolate agar (CHOC)

Under what conditions should inoculated plates for Neisseria gonorrhoeae culture be incubated?

35° C and 3% to 5% carbon dioxide

How are Neisseria gonorrhoeae infections transmitted?

Sexual Contact

Carryover of X factor-containing medium to the agar plates used for X factor requirement testing or anaerobic incubation can cause Haemophilus influenzae to be incorrectly identified as

Haemophilus parainfluenzae.

This organism is always a pathogen, regardless of the body site from which it is isolated:

Neisseria gonorrhoeae

If a male is infected with Neisseria gonorrhoeae, what would be the results of a Gram stain of purulent urethral discharge reveal?

Many polymorphonuclear white blood cells, some with gram-negative intracellular diplococci, and gram-negative diplococci

These three organisms are PYR positive:

Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus lugdunensis

In a carbohydrate substrate test, a gram-negative diplococcus produces acid only from glucose and maltose. You should suspect

N. meningitidis.

To which category do most Neisseria spp. belong?

Capnophilic

Why do Thayer-Martin and Martin-Lewis media have antimicrobial agents added?

To prevent overgrowth of normal biota

What type of swab should be used for a Neisseria gonorrhoeae culture?

Dacron

Due to the extensive antibiotic resistance associated with Neisseria gonorrhoeae, this class of antibiotic is currently recommended for treatment.

Cephalosporins

These three organisms are PYR positive:

Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus lugdunensis

A microbiologist does a Gram stain on a CSF. She sees intracellular and extracellular gram-negative diplococci. What is the most likely organism?

N. meningitidis

Which of the following is characteristic of Moraxella catarrhalis?

Tributyrin positive

Infection with this organism is a “notifiable condition” in Texas:

Neisseria gonorrhoeae

Which species of Haemophilus requires both X and V factors?

H. influenzae

Typically, all Neisseria spp. are all of the following, except

motile.

Key features of Moraxella catarrhalis include:

Gram negative diplococci, oxidase positive, butyrate disk positive

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?

Blood and cerebrospinal fluid (CSF) culture

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?

Haemophilus spp., because they need the factor V in this area

What medium will sustain the growth of most Haemophilus spp.?

Chocolate agar (CHOC)