LEC - Semifinals | Neisseria Flashcards
(162 cards)
1
Q
GENERAL CHARACTERISTICS of Neisseria species & Moraxella Catarrhalis
A
Aerobic
Non-motile
Non-spore forming
Gram-negative Diplococci
Capnophilic
2
Q
All species are cytochrome oxidase and catalase positive EXCEPT?
A
N. elongate subsp. Nitroreducens and N.
bacilliformis
3
Q
These species are both cytochrome oxidase positive and catalase positive
A
N. gonorrhoeae and N. meningitidis
4
Q
Require CO2 to grow
A
Capnophilic
5
Q
Optimal growth environment
A
Humid temperature
6
Q
Causative agent of:
- Otitis media (young children)
- Chronic upper respiratory infections (adult)
A
M. catarrhalis
7
Q
Causative agent:
- Gonorrhea (STD)
- Localized to the
mucosal surfaces
- Pelvic inflammatory
disease (complication)
- Ophthalmia neonatorum
A
N. gonorrhoeae
8
Q
2nd most commonly reported sexually transmitted infection
A
Gonorrhea (STD)
9
Q
Mucosal surfaces of N. gonorrhea infection
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- Urethra
- Endocervix
- Anal Canal
- Pharynx
- Conjuctiva
10
Q
May be asymptomatic or acute with a pronounced purulent response (presence of pus)
A
Localized infection
11
Q
Symptomatic localized infection is common among?
A
Men
12
Q
In female, it could either be asymptomatic and could further lead to complications such as?
A
Pelvic Inflammatory Disease
13
Q
It causes infertility, Ectopic pregnancy, or perihepatitis (Fitz-Hugh-Curtis Syndrome)
A
Pelvic Inflammatory Disease
14
Q
A gonococcal eye infection where the mother is tested positive for gonorrhea and passed through the child
A
Ophthalmia neonatorum
15
Q
A post-prophylaxis given; anti-microbial eyedrops which prevents further infection
A
Erythromycin
16
Q
Causative agent of :
- Meningococcemia
- Fatal bacterial meningitis
- Nasopharyngeal colonization
- Respiratory droplet secretions
A
N. meningitidis
17
Q
It is transmitted via respiratory droplet secretion and starts with nasopharyngeal colonization which can further develop to Fatal bacterial meningitis
A
Meningococcemia
18
Q
These species exclusively infects human
A
N. gonorrhoeae and N. meningitidis
19
Q
Two main diseases that can occur when N. meningitidis enters the blood stream
A
- Fulminant meningococcemia
- Meningitis
20
Q
It may occur with or without meningitis. Carrying 25% mortality rate even if treated
A
Meningococcemia
21
Q
Minor hemorrhage into the skin and mucosal membrane which can further lead to the development of bruises
A
Purpura
22
Q
Very common characteristic in meningococcemia along with the presence of petechial skin rash
A
Purpura
23
Q
These can all develop during bacteremia and consequently because of purpura and petechiae, which are manifestation of thrombosis
A
Tachycardia and hypotension
24
Q
In some cases, the disease becomes fulminant and spreads rapidly and causes:
A
- DIC (Disseminated Intravascular Coagulation
- Septic shock
- Hemorrhage in the Adrenal Canals
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Hemorrhage in the adrenal canals is also known as
Waterhouse-Friedrichsen Syndrome
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Death may develop within how many hours after onset?
12-48 hours
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Virulence factors of Neisseria
1. Receptors for human transferrin
2. Capsule (N. meningitidis)
3. Pili (fimbriae)
4. Cell membrane proteins
5. Lipooligosaccharide (LOS) or endotoxin
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Diseases caused by Neisseria are very fatal
and infectious especially in?
N. meningitidis
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The most well-characterized virulence factor
Pili or Fimbriae
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- Fine hairlike projections for initial attachment
- Inhibits phagocytosis
- Aid in the exchange of genetic material between cell
Pili or Fimbriae
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This Neisseria spp. produces a polysaccharide capsule
N. meningitidis
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It is antiphagocytic and serves as one of the important virulence factor
Capsule
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Virulence factor that plays a role in host attachment
Opacity Protein
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Helps the organism’s evasion of the complement mediated cell lysis
Lipooligosaccharide (LOS) or endotoxin
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These are other important Neisseria spp.
1. Saprophyticus Neisseria
2. Normal microbiota in respiratory culture
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Specimen collection
1. Swab – within 6 hours from collection
2. Dacron or rayon-tipped swabs
3. CO2 transport
4. 37°C in 3% to 5% Co2 - incubation
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In swabs, specimen must be plated within how many hours from collection?
6 hours
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Ideal for optimal recovery of N. gonorrhoeae
Bedside plating
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Pathogenic Neisseria are very sensitive to?
Drying and extreme temperature
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Optimal specimen for N. gonorrhoeae. If not available, swabs are acceptable
Discharge
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Reduced recovery of the organism may result as soon as how many minutes after collection?
30 minutes
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Swabs should be plated immediately in what media?
Chocolate Agar
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Most recommended swabs
Dacron or Rayon-tipped Swab
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If cotton-tipped swab is used, you must use a?
Transport medium containing charcoal (Amie's Charcoal medium)
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It inhibits toxic fatty acid present in the
cotton fibers
Amie’s Charcoal medium
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NEVER use because it inhibits the recovery of N. gonorrhoeae
Calcium alginate
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Transport media should be
INCREASED C02 or DECREASED CO2?
Increased CO2
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Atmospheric or broth requirement
37°C in 3% to 5% Co2 incubation
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Special media used to make bedside plating possible
JEMBEC plates
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JEMBEC plates contains
Modified Thayer-Martin Agar
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CO2 generating tablet is composed of
Sodium bicarbonate and Citric acid
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It activates the tablet and will generate a CO2 atmosphere in the pouch
Moisture in the agar
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Both organism are sensitive to? which is found in the blood culture bottle
Sodium polyanethanol sulfonate
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If blood culture broth is used, SPS content should not exceed
0.025%
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Vacutainer tubes containing the SPS, the specimen must be transferred to the broth cultured system within
1 hour of collection
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Body fluids (Joints & CSF) should be stored until cultured at what temperature?
37°C
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In Gram staining, we will observe the
Gram-negative diplococci
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“kidney bean shaped” or “coffee been shaped”
Gram-negative diplococci
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In males, the specimen is
Urethral discharge
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Diagnostic for males (especially if the specimen is urethral discharge)
Appearance of gram-negative diplococci inside the polymorphonuclear leukocyte
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Only presumptive evidence of gonococcal infection in symptomatic females
Direct examination of endocervical secretion
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Normal vaginal and rectal microbiota can be sometimes composed of? Which can resemble?
Gram-negative coccobacilli; Neisseria
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Specimen that should not be gram stained
Pharyngeal specimen
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Non-pathogenic commensal Neisseria may be present in this SPECIMEN and the presence of this organism is not diagnostic of infection
Pharyngeal specimen
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Pharyngeal specimen should not be gram stained because this organism may be present and its presence is not diagnostic of infection
Non-pathogenic commensal Neisseria
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Media of Choice
1. Trypticase soy agar with 55 sheep blood
2. Chocolate Agar
3. Selective medium
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Selective medium (5)
- Thayer-martin Medium
- Modified Thayer-Martin
- Martin-Lewis
- GC-Lect
- New York City medium
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It is more fastidious in typically does not grow on blood agar but will grow on Chocolate Agar
N. gonorrhoeae
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Base medium
Chocolate Agar
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The difference between the medias is that these are added
Antibiotic
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Contains chocolate agar as its base enriched with IsoVitale X and antimicrobial colistin (inhibit gram negative bacilli), nystatin (inhibits yeast), and vancomycin (inhibit gram-positive bacteria)
Thayer-Martin Medium
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It inhibits the swarming observed with
Proteus spp.
Trimethoprim
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The changes in the modification of Thayer-Martin
Includes Trimethoprim
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Antifungal agent
Anisomycin
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Similar to MTM except that anisomycin, an antifungal agent, is substituted for nystatin and the concentration of vancomycin is increased
Martin-Lewis
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In Martin-Lewis, Anisomycin is substituted for?
Nystatin
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A selective medium that contains additional
antimicrobials to inhibit bacteria found in oropharyngeal specimens; it includes vancomycin and lincomycin, colistin,
amphotericin B, and trimethoprim
GC-LECT Agar
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Antimicrobials to Inhibit gram-positive bacteria
Vancomycin and Lincomycin
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Antimicrobial to inhibit gram-negative bacteria
Colistin
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Antimicrobial to inhibit yeast
Amphotericin B
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Antimicrobial to inhibit swarming Proteus spp. and Capnocytophaga spp.
Trimethoprim
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A transparent clear-to- yellow medium containing lysed horse blood, horse plasma, yeast dialysate, and the same antimicrobials as MTM, also has been used
New York City Medium
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Advantage of New York City Medium
It inhibits the growth of genital mycoplasmas
(Mycoplasma hominis and Ureaplasma)
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Incubation Conditions and Duration
- 35°C to 37°C for 72 hours in a CO2-enriched, humid atmosphere
- Increased CO2 at 3%-7%
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Organisms that grow best under conditions of increased CO2 at 3%-7%
N. gonorrhoeae, N. meningitidis, and
Moraxella catarrhalis
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How to achieve increased CO2 at 3%-7%?
Candle jar, a CO2 generating pouch, or CO2 incubator
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They can be toxic to Neisseria, both gonorrhoeae and meningitides
Scented candles
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How to provide humidity?
By placing a pan with water in the bottom of the CO2 incubator or by placing a sterile gauze pad soaked with sterile water in the bottom of the candle jar
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All species of Neisseria are
Oxidase positive
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All species EXCEPT? are catalase positive
N. elongata
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To differentiate Gram negative rod Kingella denitrificans and Acinetobacter spp., the organism can be streaked to a plate with?
10-unit Penicillin disk
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After growth, it is stained to visualize the microscopic morphology
Edge zone of inhibition
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After penicillin disk, the microscopic morphology of N. gonorrhoeae remains?
Gram-negative diplococci
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After penicillin disk, the microscopic morphology of Kingella denitrificans is?
Gram negative rod
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After penicillin disk, the microscopic morphology of Acinetobacter spp. is?
Elongated gram negative rod
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Gram negative diplococci
Neisseria
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Gram negative rod
Kingella denitrificans
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Elongated or filamentous
gram negative rod
Acinetobacter spp.
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Reagent of Oxidase Test
1% dimethyl-p-phenylenediamine dihydrochloride or tetramethyl-p-phenylenediamine dihydrochloride
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The oxidase test must be done on all suspected isolate of
N. gonorrhoeae
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The oxidase reagent is placed on a filter, and a colony from the plate and rubbed onto the reagent with an applicator stick or non-nichrome loop
Filter paper method
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(Filter paper method)
After 10 seconds → positive result = ?
Purple color
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Alternatively, the oxidase reagent may be dropped directly onto a colony or plate of Neisseria
positive reaction = ?
Deep purple to black
104
If subculture is needed, it must be done:
BEFORE or AFTER adding the reagent?
BEFORE
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More convenient in Oxidase Test
Direct plate method
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Standard Method of Identification
- Acid production from glucose, maltose, lactose, sucrose, and fructose in a CTA base medium and a carbohydratefree control (historically)
- Buffered, low peptone substrate with the appropriate carbohydrate
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The test is used to determine the ability of an organism to hydrolyze DNA
DNAse Test
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The medium of DNAse Test is? because of the?
Pale green; DNA-methyl green complex
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If the organism growing on the medium hydrolyses DNA, what will happen to the green color?
Green color fades
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If the organism growing on the medium hydrolyses DNA, what will happen to the colony, it is surrounded by?
Colorless zone
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DNAse Test is used to differentiate?
M. catarrhalis from Neisseria
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In DNAse Test, M. catarrhalis is?
DNAse positive
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In the presence of hydrochloric acid:
When there is clear zone surrounding the inoculum, streak with the rest of the plate remaining opaque
RESULT: DNAse-positve or DNAse-negative?
DNAse-positive
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In the presence of hydrochloric acid:
Absence of a clear halo around the inoculum streak
RESULT: DNAse-positve or DNAse-negative?
DNAse-negative
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DNAse-positive RESULT in the presence of toluidine blue
Appearance of pink halo surrounding the inoculum streak. The rest of the plate remains blue
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DNAse-negative RESULT in the presence of toluidine blue
Absence of the pink halo surrounding the inoculum
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There is opacity in the presence of?
Hydrochloric acid
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There is a pink halo in the presence of?
Toluidine blue
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Historical or traditional method used to identify Neisseria spp.
Carbohydrate Utilization Method - CTA
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Carbohydrates that can be added in each tube of CTA
Glucose
Lactose
Maltose
Sucrose
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Positive result in Carbohydrate Utilization Method - CTA, and due to?
Yellow color; acid production
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After incubation in Carbohydrate Utilization Method - CTA, examine the tube within how many hours for a yellow color?
24 to 72 hours
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The pH indicator will turn to what color if the carbohydrate is utilized?
Yellow
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Precaution in Carbohydrate Utilization Method - CTA:
Avoid incubation in CO2 because it may alter the pH of the media which may cause
FALSE POSITIVE REACTION or FALSE NEAGTIVE REACTION?
False positive reaction
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Precaution in Carbohydrate Utilization Method - CTA:
A yellow color can also change throughout the tube that may also indicate presence of
Contaminating organisms
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It is positive for glucose only in Carbohydrate Utilization Method - CTA
N. gonorrhoeae
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It is positive for Glucose and Maltose in Carbohydrate Utilization Method - CTA
N. meningitidis
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It is positive for glucose, maltose, and lactose in Carbohydrate Utilization Method - CTA
N. lactamica
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This organism is only negative for Lactose in Carbohydrate Utilization Method - CTA
Non-pathogenic Neisseria
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Negative for all carbohydrates in Carbohydrate Utilization Method - CTA
Maroxella catarrhalis
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Preferred assays for the detection of N. gonorrhoeae in clinical specimens because it has increased sensitivity, specificity, and ability to test with the non-invasive urine specimens
Nucleic Acid Amplification Tests (NAAT)
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This test will provide faster detection of Neisseria
Nucleic Acid Amplification Tests (NAAT)
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In NAAT, this specimen is used
Urine
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Its advantage is being less sensitive to transport and storage conditions compared with culture
Nucleic Acid Amplification Tests (NAAT)
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One of the advantages of NAAT is that it can detect both of these organisms in the same specimen
N. gonorrhoeae and Chlamydia trachomatis
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It exists as a co-infection of Chlamydia trachomatis
N. gonorrhoeae
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Conditions that NAAT is NOT recommended
- Cases of child sexual assault involving boys
- Extragenital infections (rectal or oropharyngeal) in prepubescent girls
- Urethral specimen from boys and extragenital from both boys and girls
- Culture for N. gonorrhoeae is necessary to monitor antimicrobial resistance
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In cases of child sexual assault involving
boys and extragenital infections (rectal or oropharyngeal) in prepubescent girls, this is RECOMMENDED
Culture
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What is preferred when the condition presents diagnosis of sexual abuse
Culture
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Only method to monitor the effectiveness of treatment because NAATs are not approved for use as a test of cure
Culture
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Culture for this organism is necessary to monitor antimicrobial resistance
N. gonorrhoeae
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Conditions that NAAT CAN be used
Vaginal or urine specimens from young girls
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Chromogenic substrate enzyme tests:
Prolyl-hydroxylprolyl aminopeptidase is for?
N. gonorrhoeae
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Chromogenic substrate enzyme tests:
Beta-galactosidase and gammaglutamyl aminopeptidase is for?
N. meningitidis
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ONPG means
O-Nitrophenyl-B-Galactopyranoside
146
This test is used to differentiate N. lactamica and N. meningitidis
ONPG Test
147
In ONPG Test, it is used determine the organisms ability to produce?
Beta-galactosidase
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- Enzyme present in lactose fermenters
- Very important for enteric
Beta-galactosidase
149
Organisms present with beta-galactosidase
enzyme indicate it as a?
True lactose fermenter or lactose utilization
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ONPG positive organism
N. lactamica
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ONPG negative organism
N. meningitidis
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This organisms are not routinely identified in the clinical laboratory
saprophyticus Neisseria
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This organism may be misidentified as N. gonorrhoeae if the isolate produces a weak positive glucose reaction in the acid production
Neisseria cinerea
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This organism can grow in the nutrient agar at 35°C; it is saprophytic Neisseria
N. cenerea
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It will not grow in nutrient agar, only on chocolate agar
N. gonorrhoeae
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Can N. cenerea be inhibited by Colistin?
YES
157
Can N. gonorrhoeae be inhibited by Colistin?
NO
158
Moraxella catarrhalis can be differentiated from the gonococci and meningococci based on its growth on?
Blood agar at 22°C
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This organism can grow on BAP with sheep blood agar
Moraxella catarrhalis
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This organism can reduce nitrate to nitrite and cannot utilize any carbohydrates
Moraxella catarrhalis
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It is negative to all carbohydrate utilization test but positive for DNAse
Moraxella catarrhalis
162
The only member of this group that hydrolysis DNA
Moraxella catarrhalis
