N.Gonorrhea, N.Meningitidis Flashcards
Is neisseria aerobic or anaerobic?
Neisseria is AEROBIC
Gram? why?
Gram negative - thin peptidoglycan with a outer lipid membrane - DO NOT TAKE THE PURLE STAIN
What shape is Nerisseria
coffe bean shape - cocci
Is Neisseria oxidase positive or negative and why?
Neisseria is oxidase positive - HAS OXIDASE ENZYME
> oxidase test: to identify bacteria that produce cytochrome c oxidase (E) - part of ETC
> All bacteria that are oxidase positive = aerobic + use O2 as a terminal electron acceptor in respiration
Is Neisseria catalase positive or negative?
CATALASE POSITIVE
> catalase = produced by bacteria that respire using oxygen (AEROBIC BACTERIA) and protects them from the toxic by-products of oxygen metabolism
Catalase-positive bacteria > strict aerobes as well as facultative anaerobes
IS neisseria motile or non-motile?
Neisseria is non-motile - not able to move
Outline the main human pathogenic species of Neisseria
> Neisseria gonhorreah
> Neisseria meningitides
How is Neisseria Gonnorheah (gonococci) transmitted?
transmitted by sexual contact
Is Neisseria Gonnorhhea Gram positive or negative?
Neisseria Gonorrhea is gram negative because it has thin peptidoglycan in cell wall and doesn’t take the purple dye of gram stain
What does Neisseria Gonorrhea produce from glucose only and not from any other sugars.
Produces acid from glucose
Outline the disease Neisseria Gonorrhea found in MEN ONLY:
causes URETHRITIS = EPIDIMYTIS
> acute + symptomatic
purulent discharge + dysuria (urination pain)
can be transmitted to sexual partner if not treated soon enough
2 bacteria responsible for urethritis in men:
- neisseria gonorrhea
- chlamydia trochomatis
What 2 bacteria are responsible for the cause of URETHRITIS IN MEN?
> Neisseria Gonorrhea
> Chlamydia trochomatis
What diseases does Neisseria Gonorrhea cause in WOMEN ONLY?
CERVICITIS
VAGINITIS
PELVIC INFLAMMATORY DISEASES (PID)
DISSEMINATED GONOCCAL INFECTION (DGI)
> asymptomatic
often untreated until PID complications develop
PID can lead to scaring of fallopian tubes and infertility
What staining stains Nesseria pink as it is gram negative?
REMEMBER ALL GRAM NEGATIVE B stain PINK
Safranin dye
What kind of aerobes are Nesseria and what does it mean?
Obligate aerobes, means they MUST need oxygen to survive
What culture is used for Nesseria Gonorrhea?
Chocolate medium = THAYAR MARTIN AGAR
What test is done to differentiate between Nesseria Gonorrhea and Nesseria Meningitidis?
Maltose Fermentation test:
> N. Gonorrhea cannot ferment maltose
N. Meningitidis can ferment maltose
Process:
> Bacterium added to PHENOL RED MALTOSE broth
N. gonorrhea cannot ferment maltose»_space; broth stays red colour
N.meningitidis can ferment maltose»_space; products makes the broth turn yellow
Is Nesseria Gonorrhea capsulated or non capsulated?
Not capsulated : does not have a polysaccharide capsule
Outline the virulence factors of Nesseria Gonorrhoea?
> pili on surface
antigenic proteins (can vary)
toxins: IgA protease
catalase
Explain the virulence factor pili on N. gonorrhea
pili on surface = help with attachment on host mucosal surface + allow bacteria to physically connect with each other = forming conjugation of pillus»_space; through this bacteria can swap genetic information including resistant genes
Explain the virulence factor antigenic proteins on N.gonorreah
antigenic proteins (can vary) so no specific quick response from immune cells and no specific vaccines
Explain the virulence factor toxins of N.gonorrhea
toxins: IgA protease - toxic protein used to destroy IgA produced by the host
Explain the virulence factor catalase of N.Gonorrhea
catalase: when neutrophil opsonises the bacteria - inside phagosome - hydrogen peroxide is release to kill the bacteria
HOWEVER - BACTERIA releases CATALASE enzyme which breaks down and destroys HYDROGEN PEROXIDE - and will now use the energy from the neutrophils for its own growth and replication
What antimicrobials are used to inhibit growth of undesired bacterium in the chocolate agar culture for N.gonorrhea?
Antimicrobials:
>vancomycin
>Nystatin
What is gonococcemia? How does it occur?
N.GONORRHEA in BLOODSTREAM!
When the phagosome are no longer able to release H2O2 due to CATALASE (E) released by the bacteria, the bacteria grows and multiplies until the phagosome burst open and releasing the bacteria into the blood stream = GONOCOCCEMIA
What other diseases can N.gonorrhea cause once it enters the blood stream?
SEPSIS: wide spread immune response (fatal)
> Cell wall of N.gonorrhea contain Ag - LOS - lipoolligosaccharides - which can trigger a wide spread immune response
> Cause blood vessels to dilate and BP drops»_space; ORGANS NOT RECEIVING ENOUGH BLOOD
What is SIALYLATION?
Camouflage effect by the bacteria:
>hides it’s Ag LOS with SIALIC ACID
>Ag now unable to recognise by host cell
>not able to produce immune response against B
To what other organs can N.gonorrhea travel in bloodstream?
>Joins = gonococcal arthritis >Heart = endocarditis
Outline how diagnosis is done for N.gonorrhea?
> biological specimens:
1)urethral/ vaginal swap
2)gram staining > gram negative
>pink colour due to safranin dye (for all gram negative bacteria)
3) B grown on culture medium: chocolate agar = THAYER MARTIN AGAR (antimicrobial added -vancomycin to prevent growth of any other microbes)
4) Nucleic Acid Amplification Test (NAAT) = done to further identify genetic material of B
Outline the antibiotic treatment for N.gonorrhea?
3rd generation CEPHALOSPORINS (CEFTRIAXONE)
What other disease can also be expected with N.Gonorrhea and why?
CHLAMYDIA TROCHOMATIC - common to appear with N.gonorrhea as it is also sexually transmitted infections
THEREFORE > must be treated together with CEPHALOSPORINS
> must also take»_space; AZITROMYCIN
»_space; DOXYCYCLINE
Is N.meningitidis gram positive or gram negative and why? What stain?
Gram negative = thin peptidoglycan in cell membrane
> does not stain purple
> stains pink - SAFRANIN DYE
What shape is N.meningitdis ?
> ROUND SHAPE
DIPLOCOCCI
COFFEE BEAN SHAPE
What diseases does N.Meningitidis cause?
> Meningitis
> Sepsis
> DIC = Disseminated intravascular coagulation (protein that control blood coagulation becomes overactive)
Outline the 3 main morphology of N.Meningitidis?
> Non motile
Non sporing
Obligate aerobes = must require O2 to survive
Is N.meningitidis CATALASE AND OXIDASE positive or negative?
CATALASE + OXIDASE POSITIVE
Catalase: destroys H2O2 produced by phagosomes so they won’t get killed by the phagosome and continue to grow and multiply inside it
What culture medium is used for N.meningitidis?
Chocolate agar > Thayer Martin Agar
Antimicrobials added to the culture to prevent growth of other bacterial species
>vancomycin
>nystatin
What test differentiates between N.gonorrhea and N.meningitits?
Maltose Fermentation Test
> N.gonorrhea cannot ferment maltose so NO COLOUR CHANGE (RED»_space; RED)
> N.meningitidis can ferment maltose so COLOUR CHANGE (RED»_space; YELLOW)
Outline the virulence factors of N.meningitidis?
> capsulated - polysaccharide layer
> pili > help to attach to HOST CELLS
> outer membrane - OPACITY PROTEINS (phase variable expressions) - also help to attach to HOST CELLS
OPA
OPC
> TOXINS: IgA protease - destroys host IgA (immune system protein which tags bacterias for neutrophils)
> factor H binding protein in blood
What is MENINGOCOCCEMIA?
When N.meningitidis enters the blood stream
> why?
- once inside the neutrophils phagosome - CATALASE enzyme of the bacteria destroys the H2O2 which means the phagosome is no longer able to destroy the bacteria so it continues to grow and multiply inside the neutrophil»_space; causing it to burst open and enter the bloodstream
What other toxic factor does N.meningitis release when in bloodstream?
> FACTOR H BINDING PROTEIN
-disables FACTOR H which is involved in alternate complement pathway + helps with anti-bacterial pathway
> allows the B to spread, multiply and produce more toxins in bloodstream
destroying capillary endothelium»_space; LEAKY CAPILLARIES
Explain the function of LOS (lipooligosacharide) in N.meningitis
LOS - lipooligosaccharide
>Antigen found on the cell wall
>triggers wide spread immune response in HOST - SEPSIS
>blood vessels dilate > BP drops and ORGANS don’t receive enough blood
MENINGOCOCCAL SEPSIS»_space; lead to DIC (disseminated inter vascular coagulation)
What other disease can MENINGOCOCCUS SEPSIS LEAD TO?
DIC (disseminated intravascular coagulation)
> coagulating protein factor becomes over active
Who is at more risk with N.Meningitis?
People with weak immune system or with spleen problems (splenectomy)
>HIV >CANCER >ELDERLY >INFANTS >DIABETES >ALCOHOL + DRUGS
Explain how meningitis occurs and N.meningitis enters CSF?
> N.meningitis enters bloodstream (phagosome -catalse…)
via bloodstream reacher blood-brain barrier
uses its toxins to destroy capillary endothelium cells
can now enter CSF
What are the symptoms of Meningitis?
Headache
Fever
Neck stiffness
What are the symptoms of Meningococcemia?
Petechial rash
Sepsis (shock)
How is N.meningitis diagnosed?
> look for N.meningitis in blood samples or CSF
> CSF taken by lumbar puncutre
How is N.meningitis treated?
> CEFTRIAXONE can be followed by Penicillin
> Prophylactics: >given to anyone in close contact
- ceftriaxone
- rifampin
- ciprofloxacin
What vaccines are used for N.Meningitis?
1) menigiococal conjugate vaccine = infants under 2 years old
2) meningococcal recombinant vaccine = adults
What N.Meningitis vaccine is given for infants under 2yrs?
Meningiococcal conjugate vaccine
What N.meningitis vaccine is given for adults?
Meningococcal recombinant vaccine
