Gram Negative Bacteria Flashcards
What colour do gram negative bacteria stain when the gram stain test is conducted?
Pink/red
What are the three layers of the gram positive cell wall?
Outer membrane
Periplasmic space
Cytoplasmic mebrane
The Neisseria species grow well in what conditions?
37 C
5% CO2
On chocolate agar
What is the result of the cytochrome c oxidase test for the Neisseria species?
An oxidase positive test
What infections does Neisseria meningitidis cause?
- Meningitis
- Septicemia
- septic arthritis
- conjunctivitis
- endophthalmitis
What are the 5 out of 12 subgroups of Neisseria meningitidis cause most infections
A
B
C
W
Y
What test is commonly done to diagnose meningococcal meningitis
Spinal fluid sample
- positive test is a cloudy sample (WBC present)
- negative test is a clear sample
What is are two common symptoms of meningococcal meningitis?
neck stiffness
photophobia
Symptom of meningococcal speticaemia
purpuric, non blanching rash (doesnt go away when glass is pressed onto it.
Neisseria gonorrhoeae is difficult to cultivate in the lab.. WHy?
- they dont have a capsule making them fragile
-they don’t tolerate drying and must be inoculated immediately
Which type of media is used to grow neisseria gonorrhoeae?
Selective media such as Modified Tahyer-Martin of MNYC as they inhibit the growth of commensal organisms
What are the infections caused by neisseria gonorrhoeae in men, women and neonates?
urethritis in men
cervicitis in women (extremely negative sequelae like pelvic inflammatory disease)
ophthalmia neonatorum in neonates (eye disease)
Infections caused by Moraxella catarrhalis
-otitis media
- sinusitis
-pnuemonia (in immuno compromised peeps and the eldery)
What tests can be done to diagnose or identify Escherichia coli species?
See if it can ferment lactic acid (streak on macconkey agar)
indole test (positive test as a result)
MALDI-TOF
Infections cause by Escherichia coli
UTI (70% of community acquired caused by e.coli)
Neonatal
wound infection
intra abdominal abscess
diarrhoea
Haemolytic uraemic syndrome
Diseases caused by Legionella?
pnuemonia
Characteristics of Vibrionaceae
Comma shaped, short
Actively motile
Fermenter
Oxidase positive
What media is vibrionaceae grown on?
TCBS (thiosulphate, citrate bile salt sucrose) agra
alkaline peptone water
Example of a vibrionaceae
V.cholera
What conditions are used to grow H. influenzae in the lab?
Chocolate agar
CO2
Haemin
and NADP
H. influenzae causes many invasive disease due to what?
Serotype B
What are some examples of disease caused by H. influenza?
meningitis
epiglottitis
bacteriaemia
pnuemonia
septic arthritis
cellulitis
What is needed to grow Legionella in the lab
Buffered charcoal yeast extract agar (BCYE) with alpha keto gluterate
