Aerobic Gram Negative Cocci Flashcards
Does Neisseria sp. require enriched media? If so, what are some examples?
Yes, CHOC and gonococcal selective media. Important: also requires increased CO2
Oxidase pos
Catalase pos
What type of bacteria is this?
Neisseria sp.
How can the ID of Neisseria sp. be aided?
With the ability to utilize carbs (sugars) in CTA agar
Is Neisseria gonorrhoeae normal flora of mucous membranes?
No, this is the only one that isn’t normal flora in this type of bacteria.
What are the 2 pathogenic species in Neisseria sp.?
N. gonorrhoeae and N. meningitidis
What bacteria originally thought to be the causative agent of syphilis? (“The clap”)
Neisseria gonorrhoeae
What type of bacteria is referred to as gonococci? Is humans the only natural host for this kind of bacteria?
Neisseria gonorrheae; yes
What does Neisseria gonorrhoeae primarily affect in the body?
Urethra, endocervix, anal canal, pharynx, conjuntiva
Name this bacteria:
Transmitted most commonly by sex
Nationally reportable disease
Many carriers are asymptomatic
Highest rates in southeastern US
Neisseria gonorrhoeae
What is the incubation period for Neisseria gonorrhoeae?
2-7 days
Neisseria gonorrhoeae infection in males causes:
Acute urethritis: purulent discharge and dysuria (urethral exudate smears - sensitive and specific - presumptive ID
Most infections are symptomatic 95%
Infections of prostate and epididymis
Neisseria gonorrhoeae infections in females causes:
Up to 50% causes asymptomatic
Gram stain less reliable as presumptive ID
Endocervix is most common site of infection
Vaginal discharge, dysuria, lower abdominal pain
What does untreated infections of Neisseria gonorrhoeae in females cause?
May lead to Pelvis Inflammatory Disease (PID), which leads to infertility or ectopic pregnancy
What are 4 disseminated infections in N. gonorrhoeae?
Septicemia: typically not recovers in commonly utilized blood culture due to inhibition by anticoagulant
Infections of synovial fluid: bacteria hangs out in joints causing pain and swelling
Fever
Rash
Are eye infections possible with N. gonorrhoeae?
Yes, If they are in contact with infected genital secretions
What is a gonococcal eye infection that newborns squire through vaginal delivery from infected mother? It can often result in blindness if not treated immediately
Ophthalmia Neonatorum
What is Neisseria meningitidis referred to as?
Menigococci
Is Neisseria meningitidis normal flora?
Yes, found in naso and oropharynx of many adults
What does Neisseria meningitidis cause?
Meningitis
Meningococcemia
Pneumonia
Purulent arthritis
Endophthalmitis
How many serogroups does Neisseria meningitidis have?
13; meningitis outbreaks of college students
Epidemic meningitis sources caused by N. meningitidis are often from:
Asymptomatic carriers, oral secretions, respiratory droplets, groups with close contact
Symptoms of meningitis from N. meningitidis
Quick onset of frontal headache, stiff neck, fever (sometimes)
What is Meningococccemia?
Sepsis with N. meningitidis
What is the mortality rate of Meningococcemia, even if treated?
25%
Symptoms of Meningococcemia:
Purpura (hemorrhaging into skin/mucous membranes)
Petechial rash (pinpoint red rash)
Tachycardia
Hypotension
Is Meningococcemia a slow spreader, or does it rapidly spread?
Spreads rapidly
What could Meningococcemia lead to?
Disseminated Intravascular Coagulation (DIC)
Septic shock
Waterhouse-Friderichsen syndrome (hemorrhage in adrenal glands)
Oxidase pos
Catalase pos
Indoxyl acetate pos
Produces B-lactamase (resistant to penicillins)
Moraxella catarrhalis
What media can Moraxella catarrhalis grow on?
SBA and CHOC
This type of bacteria has colones that are often referred to as “hockey pucks” or “scooter” as they glide across the surface of the media
Moraxella catarrhalis
What type of media does Moraxella catarrhalis not grow on?
Gonococcal selective media
Infections associated with Moraxella catarrhalis:
Common flora of upper respiratory tract
Opportunistic pathogen
Upper respiratory tract infections
Otitis media
Sinusitis
Why should you avoid disinfectants when collecting Neisseria spp.?
Organisms susceptible to some agents
What types of swabs should be used to collect Neisseria spp.?
Dacron or Rayon swabs, NOT cotton or calcium alginate!
Should you wait to inoculate agar with Neisseria spp., or inoculate it immediately?
Inoculate immediately or use transport medium
Should you refrigerate Neisseria spp.?
No! Do not refigerate
What types of medias are used for Neisseria sp.?
CHOC
Martin Lewis
Modified Thayer Martin (MTM)
Thayer Martin (TM)
Jembec System (MTM with CO2 generator)
What type of atmosphere does Neisseria sp. needs to be grown in?
3 - 5% CO2 (can use incubator or candle jar)
How to prepare a candle jar:
Media in jar, light candle, close lid, place jar in 35 C incubator
Will N. gonorrhoeae grow on SBA?
No, only grows on CHOC and selective media
What does N. gonorrhoeae colones look like?
Small grayish white (tan?), appear 24-48 hrs
What types of medias does N. meningitidis grow on?
SBA
CHOC
Selective agars
What does N. meningitidis colonies look like?
Typically wet, grey colonies; others may be pigmented
What medias will Saprophytic Neisseria sp. grow on?
SBA and CHOC
Typically do not grow on selective media
What does Saprophytic Neisseria sp. colonies look like?
May be pigmented (yellow), dry, mucoid, adherent, or white
What types of medias does Moraxella catarrhalis grow on?
SBA and CHOC at 35-37 C and increased CO2
Also grows in 24-48 hrs
What does Moraxella catarrhalis colonies look like?
“Scooter” or “hockey puck” - colonies slide across agar when pushed
What percent Catalase is positive for all aerobic gram negative cocci?
3% Catalase
What percent Catalase shows vigorous bubbling with N. gonorrhoeae and weak bubbling or no reaction with other species?
30% Catalase
What does oxidase testing detects?
Detects presence of cytochrome c oxidase
What is the reagent used for the Oxidase rapid method?
1% tetramethly-p-phenlyenediamine
What color is a pos reaction for a Oxidase test?
Blue
What does Cystine Trypticase agar (CTA) contain?
Contains 1% of each carb to be tested: glucose, sucrose, maltose, lactose
CTA agar reaction with yellow color change with phenol red indicator means
This means that there was a utilization of carbohydrate(s)
How to inoculate CTA agar:
2-3 isolated colonies, insert loop into top 1/4 of media and wiggle to remove bacteria
Keep cap tight
Incubate 35C in Non-CO2 for 24-48 hrs
Keep 48 hrs before discarding and calling negative
Positive versus negative reaction in CTA agar
Yellow = pos
CTA stays red = neg
What is the Microbial ID System called to test lots of reactions at one time?
API NH
Look back in notes on Chart starred and Flowchart
What is used for rapid ID of M. catarrhalis?
CLSI M35-A
For gram neg diplococci that are oxidase positive and grow on both SBA and CHOC, a positive rapid butyrate esterase or tributyrin test identifies M. catarrhalis.
Limitation: most other Moraxella species are pos for this test, but are coccobacilli, not diplococci
Green = positive
How can GC or N. gonorrhoeae be rapidly detected?
By molecular assays - typically detects GC and chlamydia trachomatis simultaneously
Can rapid ID be used to ID N. gonorrhoae in child sexual abuse cases?
No, cannot be used in cases involving boyd and recital and oropharyngeal infections in prepubescent girls and when evaluating a potential gonorrhea treatment failure
Is susceptibility testing routinely preformed on aerobic GNC?
No
For the Cefinase method: Neisseria spp. are ____
For the Cefinase method: M. catarrhalis is typically ____
Variable; positive
A patient is seen complaining on pain in her knees and a recent history of a rash on her legs. A synovial fluid was sent to the lab for gram stain and culture. The specimen was reported as:
* Many WBCs
* Rare intracellular Gram neg diplococci
The synovial fluid was cultured to SBA, CHOC, and MAC. After 24 hrs incubation at 37C in CO2, small tan colonies are seen on CHOC; SBA and MAC are NG.
What does this information tell you about the organism?
Would you perhaps consider this significant growth or perhaps media contamination?
What types of testing might you perform on the colonies to determine ID?
What organisms would you suspect?
Fastidious organism
Significant growth
Oxidase, Catalase, Sugar test
Gonorrhea
Name all bacterias that are Aerobic Gram Negative Cocci
Neisseria sp.
-Neisseria gonorrhoeae (GC)
-Neisseria meningitidis
-Saprophytic Neisseria sp.
Moraxella catarrhalis
Most Neisseria species are:
a. oxidase positive, gram positive diplococci
b. oxidase positive, gram negative diplococci
c. oxidase negative, gram negative diplococci
d. oxidase negative, gram positive diplococci
b. oxidase positive, gram negative diplococci
Asymptomatic gonococcal infections in women may result in:
a. pelvic inflammatory disease
b. ectopic pregnancy
c. Fitz-Hugh-Curtis syndrome
d. All of the above
d. All of the above
What is the optimal specimen to collect for the diagnosis of gonorrhea by culture in male patients?
a. pharyngeal swab
b. rectal swab
c. urethral swab
d. urine
c. urethral swab
Direct gram stain for the diagnosis of gonorrhea:
a. Is appropriate on vaginal specimens
b. Can accurately detect urethritis in males
c. Can accurately diagnosis gonococcal pharyngitis
d. All of the above
b. Can accurately detect urethritis in males
Identify a selective medium that allows the isolation of N. gonorrhoeae and N. meningitidis.
a. SBA
b. CHOC agar
c. Modified Thayer-Martin
d. All of the above
c. Modified Thayer-Martin
Identify the test that can be used for definitive identification of both N. gonorrhoeae and N. meningitidis.
a. gram stain
b. catalase
c. oxidase
d. carbohydrate utilization
d. carbohydrate utilization
A limitation of nucleic acid amplification tests for diagnosing gonorrhea is that the tests:
a. are rapid and sensitive
b. require viable organisms in the specimen
c. are not approved for use in children
d. require strict transport conditions
c. are not approved for use in children
Moraxella catarhalis is not often associated with:
a. Meningitis
b. Septicemia
c. Endocarditis
d. Lower respiratory tract infections
d. Lower respiratory tract infections
Entrance of N. meningitidis into the bloodstream may lead to:
a. meningococcemia
b. meningitis
c. Waterhouse-Friderichsen syndrome
d. All of the above
d. All of the above
Which organism is an opportunistic pathogen associated with otitis media and sinusitis in children?
a. N. lactimica
b. N. meningitidis
c. N. sicca
d. M. catarrhalis
d. M. catarrhalis
Describe the colony morphology of M. catarrhalis, and explain how it is identified in the lab.
-grows on SBA and CHOC agar
-smooth, opaque, gray-white colonies
-“hockey puck” colony because it remains intact when pushed across the plate with a loop
-older colonies may have a wagon wheel appearance
-oxidase and catalase positive
-asaccharolytic
-differentiated from Neisseria by positive DNase or butyrate esterase reactions
Erythromycin eye drops are placed in the eyes of newborns to prevent infections caused by:
a. N. meningitis
b. N. gonorrhea
c. N. cinerea
d. M. catarrhalis
b. N. gonorrhea
