Concepts in Infection Flashcards
4 bugs that don’t gram stain
mycobacterium tuberculosis,
chlaymdiia,
treponema pallidum (syphillis),
mycoplasma
Gram positive - what causes it to be purple on gram staining?
thick peptidoglycan layer traps it
Gram negative - what causes it to be pink?
thin peptidoglycan layer s crystal violet is easily rinsed away leaving behind red dye
What is on outside of gram negative organisms? What is it’s significance?
Outer membrane has lipopolysacchardies which are highly charged and contribute to pathogenicity of gram -ves, is an endotoxin
unpasteurised milk associated bugs (4)
brucella,
listeria,
Salmonella,
E.coli
Coliforms are gram -ve rods. List 5 coliforms
e.coli, klebsiella, proteus, enterobacter, serrate
E.coli can cause what in neonates? (2)
HUS,
neonatal meningitis,
ciprofloxacin side effects (4)
c.difficile,
lowers seizure threshold so for people,
AA ruptures,
tendonitis
Antibiotics that may be active against gram negatives (6)
beta lactates, aminoglycosides, macrolides, tetracyclines, chloramphenicol, co-trimoxazole
Atypical pneumonias - why are they called atypical?
present atypically to pneumococcus
Mycoplasma peaks every how many years
4 years
bronchiectasis associated with what bacterial lung infection
pseudomonas
COPD
morexella
coxiella associated with what job
farmers
psittacosis associated with what
parrots,
parakeets
mild to - moderate CAP bugs
pneumococcus,
haemophilus influenzae
what type of bug is haemophilus influenzae and what antibiotic
gram negative coccobacillus - amoxicillin or doxy
What was associated with haemophilus influenza type b
hearing loss,
vaccine changeds
List 4 atypical pneuomonias
mycoplasma pneumonia,
acute coxiella brunette,
chlamydophila psittaci,
legionella
Atypical pneumonias respond to what (4)
doxycycline, (but not legionella!!),
clarithromycin,
quinolone,
amoxicillin doesn’t work!!
First choice for legionella
quinolone e.g. levofloxacin
Legionella associated with what
lukewarm water,
showers,
air conditioning,
taps
Legionella is more common in those with what (7)
smokers, males, COPD, immunosuppressed, malignancy, diabetes, dialysis
Gram negatives associated with sepsis (6)
e.coli, Klebsiella, Enterobacter, Pseudomonas aeruginosa, Neisseria meningitidis, Neisseria gonorrhoea
Gram +ve bacilli to know (4)
corynebacterium (diphtheria),
clostridium,
listeria,
bacillus
corynebacterium disease
diphtheria - can cause prosthetic infection
clostridium diseases
tetanus,
colitis,
perfringens - skin/soft tissue
Bacillus cereus
gastroenteritis
listeria diseases
gastroenteritis, septicaemia, meningitis, encephalitis, pneumonia, neonatal, endocarditis (risks = soft cheeses, unpasteurized milk, meats)
IV antibiotics preferable for sepsis most of the time. When are oral antibiotics good for sepsis?
c.diff
Strep in sepsis causes
strep pneumonia,
strep viridians,
group A strep,
group B strep neonates
beta haemolytic
clear zone - complete haemolysis
gamma haemolytic
nothing - no haemolysis
strep pyogenes haemolyiss
beta
strep pneuomniae haemolysis
alpha
strep viridians haemolysis
alpha
strep gallolyticus infections (2)
endocarditis,
gi associations
strep pneumonia treatment
penicillin
but if recent travel
add vancomycin!
syphillis treatment
penicillin
enterococcus
e. faecalis most common,
e. faecium
enterocossu
UTI,
endocarditis
enterococcus treatment
amoxicillin,
(amoxicillin),
vancomycin if amoxicillin resistant
staph aureus in sepsis
no longer penicillin sensitive,
fluclox IV or vancomycin IV in allergy or MRSA
staph epidermis
not as virulent as staph aureus, many fluclox resistant
staph aureus causing sepsis tends to come from what two systems
endocarditis,
pneumonia,
gram +ve bacilli in bloods - what risk factors should we check?
intra-abdo infection, skin and soft tissue, prosthetic, meningitis/encephalitis/immunosuppressed, PWID/animal skins (anthrax)
Which organism is not a typical organism in the major criteria for diagnosing endocarditis?
Escherichia species
intra-abdo sepsis bugs (3)
coliforms,
enterococci,
anaerobes
initial treatment in intra-abdo sepsis
IV amoxicillin+ gentamicin + metronidazole
step down therapy after sepsis caused by intra-abdominal infection
oral cotrimoxazole and metronidazole
intra abdo sepsis treatment if penicillin allergy
vancomycin + gentamicin + metronidazole
cholangitis/cholecystitis common bug
enterococcus faecalis
diabetic bugs acute & chronic
acute: staph aureus,
chronic:
staph aureus,
coliforms,
anaerobes
cellulitis bugs
staph aureus,
group a strep (pyogenes)
bacillus cereus differs in presentation to the other bacterial causes of gastroenteritis how
vomiting more than diarrhoea
4cs
clindamycin,
co-amoxiclav,
ciprofloxacin/quinolones,
cephalosporins
treatment for c.difficile
oral vancomycin ! normally doesn’t penetrate gut well so don’t do IV
risk factors for c.diff (6)
recent hospital stay, recent antibiotic use, use of pips, increasing age, recent surgery, immunosuppression
petting zoo (!!) & bbq (not so much), bloody diarrhoea, fever, aki - bug ?
E coli
complication of giving antibiotics in e coli with AKI
HUS
spirochetes (2)
lyme and syphilis
campylobacter presentation
usually watery diarrhoea, sometimes bit bloody but bloody normally e.coli!
C.diff what 3 tests should you think of
stool toxin & culture,
WCC,
creatinine
C.diff within how many weeks of risk factors
within 12
C.diff does alcohol gel do enough
No doesn’t kill spores
C.diff infection control procedures
isolation room,
own commode,
proper hand washing
Test for legionella
urinary antigen,
sputum PCR
Test for coxiella burnetti/chlamydophilia psittaci
serology
Mycoplasma test
PCR on viral swab
Presentation suggestive of CAP more than Covid (4)
unilateral changes,
neutrophilic,
lack of lymphopenia,
productive cough
CAP treatment and step down for strep pneumonia
IX vo-amoxiclav and oral doxy,
step down to oral amoxicillin
Cellulitis
consider tine pedis,
fluclox if mild, doxy if allergic,
sepsis fluclox or vancomycin IV,
septic shock or NEC fluxloc + clindamycin + gentamicin if allergic just clindamycin and gentamicin
When should you suspect HAP vs CAP?
If in hospital >48 hours
Pseudomonas causes (3)
Pneumonia in people with bronchiectasis,
UTI,
Otitis externa
Brucella associated with
Sheep, goats, cattle, unpasteurised milk