Classification Of Bacteria Flashcards
What are the shapes that bacteria can come in?
Streptococcus or staphylococcus. Cocci=round, bacilli=rod, spiral shaped
Streptococcus vs staphylococcus
Strep=chain and staph=clusters
Both gram positive
What bacteria is co-agulase positive and what does this mean?
Staphylococcus aureus - clots blood
Staphylococcus aureus causes…
MRSA and MSSA (methicillin resistant vs sensitive)
What will a gel sample positive with staphylococcus aureus show?
Thick gel
What are the symptoms of MRSA?
Skin boils, soft tissue infections, abscesses
What is a treatment for staphyloccus aureus caused MRSA or MSSA?
Vancomycin (glycopeptide) or linzolid (oxazolidonone)
What 3 groups can streptococci be split into?
A-haemolytic (green agar, partial haemolysis )
b-haemolytic (clear agar, full haemolysis)
non-haemolytic
How many groups can b-haemolytic streptococcus be split into?
A-G. Based on surface antigens
What is enterococcus bacteria?
Gram positive cocci in group D arranged in short chains of 2 - pairs
What bacteria is in group A b-haemolytic?
Necrotising fasciitis - flesh eating bacteria. Streptococcus pyogenes
What bacteria is a-haemolytic?
Streptococcus pneumoniae
What infections can streptococcus pneumoniae cause?
Pneumonia, meningitis, septicaemia
How can we test for streptococcus pneumoniae?
Sputum sample for pneumonia. Cerebrospinal fluid sample for meningitis.
What is an example of a gram positive bacilli bacterium?
Clostridiodes difficile
Is clostridiodes dificille aerobic or anaerobic?
Anaerobic
How is bacterium classified on a diagram?
Aerobic/anaerobic
Cocci/ bacilli
Streptococcus/staphylococcus (if relevant)
How do we identify clostridiodes difficile in a human? (It’s name)
Antigens or stool. Very difficult to culture, given its name
Where is c. difficile found and how does infection emerge?
Found in many babies and adults as part of gut commence. Infection develops usually when taking antibiotics for something else
Transmission and symptoms of clostridiodes difficile?
Releases toxins. Transmitted via spores. Causes diarrhoea, can be fatal
What colour staining can we expect to see on gram positive and negative bacteria?
P=purple. N=red
What is Coliform?
Bacteria always present on animal surfaces healthily.
What makes escherichia coli virulent?
Factors that allow it to spread illness. Capsid, pili, endotoxins, exotoxins
What is an example of a gram negative bacilli that ferments in lactose to turn pink?
Escherichia coli
What infections does E-coli cause?
urinary tract infections (UTI), septicaemia, meningitis
Where is pseudonomas found, and what infection can it cause?
Colonises soil and water. Can cause septicaemia, bacteraemia and rarely pneumonia
What antibiotics can treat pseudomonas?
Aminoglycosides - gentamycin with b-lactams (penicillin or cepharosporins) or carbapenem
Which antibiotics should be taken to treat escherichia coli?
None. Not recommended
What is bacteroides fragilitis?
An anaerobic gram negative bacteria, bacilli. Found as normal gut flora
Where in the body are gram negative anaerobes found?
GI tract and oral cavities
What infection can bacteroides fragilitis cause?
If escapes gut, Intra-abdominal abscess
Gut vs GI tract?
Gut is entire GI tract, from mouth to anus. GI includes stomach
Why are some bacteria miscellaneous?
They are neither gram positive nor negative and don’t stain using grams method
How do we stain miscellaneous bacteria?
E.g. mycobacterium, using ZN or Auramine stains
What increases an individuals chances of developing mycobacterium tuberculosis?
Having HIV
What is mycobacterium tuberculosis?
Slow growing (2-4 weeks) miscellaneous, aerobic bacterium
How genetic variation occur in a bacteria cell?
Spontaneous mutation or transfer of bacterial DNA
What is an example of a gram negative cocci?
Neisseria Meningitidis
What symptoms does N. Meningitidis cause and how do we test for it?
Causes meningitis - inflammation of meninges - and septicaemia - bacteria in the blood.
Require CSF and blood sample
What is pseudonomas?
Gram negative bacilli. Multiple drug resistant (MDR)
What is Clostridiodes Difficile?
Gram positive bacilli
What is a coliform bacterium?
Gram negative bacilli, like e-Coli, found in the gut
What are 2 other infections caused by e-coli?
Enterotoxogenic - diarrhoea in travellers
Enterohaemorragic - bloody diarrhoea - contaminated water
Who commonly develops pseudonyms and what kind of bacteria is it?
Children with cystic fibrosis. gram negative bacilli non-lactose fermenting
What are the 4 miscellaneous bacteria?
Mycobacterium, mycoplasma, spirochetes, chlamydia
What do spirochetes cause?
Syphillis and lyme disease
