bacteria Flashcards
what is a prion
abnormal form of normal human protein - no detectable nucleic acid. can change from alpha helical to beta sheet
what are the 3 different classifications of shape and gram stains of bacteria?
cocci, rod/bacilus and coccobacilli
distinguish between gram positive and gram negative bacteria
gram positive have techoic acid, a thicker peptidoglycan wall and are able to stand drying better than gram negative. Some gram positive have spores, negative never have spores. Gram positive bacteria produce exotoxins, gram negative produce endotoxins and some also produce exotoxins; they also have an outer membrane over the peptidoglycans made of polysaccharides
what is a mycobacteria? what are its characteristics?
gram positive in structure but unable to stain due to cell being rich in waxy mycolic acids
considered a weak gram positive
non-spore forming
non-motile ROD
what do you use to stain mycobacteria?
ZN stain - need heat to stain
gram positive cocci found in cluster indicate what?
staph aureus
what do staph aureus make?
exotocins
enterotoxins cause food poisoning
toxic shock toxin cause staphylococcus toxic shock, rash, renal impairment
pneumonia following influenza likely to be what bacteria?
staph aureus
pneumonia most common bacteria is?
streptococci pneumoniae
how to identify staph aureus in lab?
golden colonies on blood agar
what kind of bacteria is staph aureus?
gram positive cocci
what kind of bacteria is streptococci?
gram positive cocci
gram positive cocci found in pairs is what?
streptococci
if slightly elongated typical of streotococcus pneumoniae
what are the main strep bacteria of group a and b and what diseases do they cause?
group a: streptococcus pyogenes - sore throat, impetigo, cellulitis - flesh eating virus
group b: streptococcus agalactiae - neonatal sepsis - carried in the vagina
what diseases can staph aureus cause?
bloodstream infection, endocarditis, osteomyelitis, septic arthritis, pneumonia
where is staph aureus normally located?
skin, nasal lining, eyes, throat, numerous places in human body
where is strep normally found?
in moist openings - oral cavity, genital openings,
what are the three types of gram positive rods?
anaerobic spore forming, aerobic spore forming and non spore forming
what are examples of anaerobic spore forming bacteria and what diseases do they cause?
Clostridium bacteria eg. c. diff (antibiotic associated diarrhoea), c. tetani (causes tetanus), c. botulinum (botulism - patients can die of respiratory failure)
what are examples of aerobic spore forming bacteria and what diseases do they cause?
bacillus species e.g. b.anthracis, b.cereus (food poisoning)
what are examples of non spore forming bacteria and what diseases do they cause?
corynebacterium dipptheria, Listeria (blood stream infection, meningitis and neonatal sepsis)
what are examples of gram negative cocci
Neisseria family - meningitides or gonorrhoea
what kind of bacteria are neisseria bacterias? and what diseases do they cause?
Gram negative cocci
meningitis (can progress to spesis with bloodstream invasion + haemorrhagic rash), gonnorhoea
what are examples of gram negative rods?
Enterobacteriocae - e.coli, klebsiella, salmonella, proteus
pseudomonas aeruginosa
legionella
haemophillus influenza
what are the common enterobacteriacae? and what diseases do they cause?
e.coli, klebsiella, proteus, salmonella
infections of urinary tract, bloodstream; bacterial food poisoning; intraabdominal infections such as appendicitis
when are you likely to have a pseudomonas aeruginosa infection and what does it cause?
in healthcare setting, and in immunocompromised patients
causes bloodstream and urinary tract infections
when are you likely to have a legionella infection and what does it cause?
in poorly maintained water situations - stagnant pools of water contaminated around - cooling system perhaps
causes pneumonia
what kind of bacteria is haemophillus influenza?
gram negative rod
what kind of bacteria is legionella?
gram negative rod
what kind of bacteria is e.coli?
gram negative rod
what kind of bacteria is proteus?
gram negative rod
what kind of bacteria is salmonella?
gram negative rod
what kind of bacteria is pseudomonas?
gram negative rod
how do you identify different streptococci from each other in the lab?
see alpha haemolysis for streptococci pneumonitis, see beta haemolysis for strep agala and strep
when would you use PCR to indentify bacteria?
when other methods are too difficult, insensitive or take too long - can rapidly diagnose many respiratory viruses: RSV, influenza a and b, rhinovirus, parainfluenza
how do you identify chlamydia or neisseria gonorrhoea
with PCR
define SEPSIS
SIRS + caused by known or suspected infection
SIRS requirement: at least 2 of the following
- HR over 90
- RR over 20
- temp over 38 or below 36
- WBC over 12k or below 4k
What are the SEPSIS 6
- give high flow oxygen
- take blood cultures
- give broad spectrum antibiotics (IV if possible)
- give IV fluids
- measure serum lactate and haemoglobin
- measure accurate hourly urine output
must all be done within first hour to double patients chances of survival