microbiology Flashcards
how does gentamicin work
bactericidal, inhibit protein synthesis acting at 30s ribosome
how is gentamicin given
IM or IV
what bacteria does gentamicin work against
S.aureus
e.coli
klebsiella
pseudomonas aeruginosa
indiactions gentamicin
sepsis
biliary tract infections
acute pyelonephritis and prostatitis
endocarditis
HAP
CI/cautions with gentamicin
excretion via kindeys - increase dosing interval in renal impairment
avoid in pregnancy and myasthenia gravis
how does clindamicin work
bacteriostatic, inhibit protein synthesis acting at 50s ribosome
ow is clindamicin given
oral, IM, IV
what bacteria does clindamycin work against
S.aureus, haemolytic strep, clostridium perfringens, bacteroides fragillis
no gram neg cover
inidcation clindamycin
alternatibe to penicillin in staph infection
peritonitis
SE clindamycin
c.diff
abdo discomfort
oesoohagitis
taste disturbance
SJS
TEN
ED
how does ertythromycin work
bacteriostatic, inhibit protein synthesis acting at 50s ribosome, doesnt cross BBB
adminisering erythromicin
oral, IV
what bacteria does erythromycin work against
S.aureus, haem strep, strep pneumoniae, legionella, mycoplasma pneumoniae, chlamydia
indications erythromycin
alternative to penicillin
campylobacter enteritis
syphilis
non gonococcal urethritis
atypical pneumonia
chronic prostatiis
group a strep
cellulitis
whooping cough
acne vulgaris
rosacea
cautions/CI erythromycin
prolong QT
SE erythromycin
QT prolongation
nausea and vom
diarrhoea
phlebitis
myasthenia like syndrome
how does vancomycin work
bactericidal
what bacteria does vancomycin work against
staph aureus,
staph epidermidis
haem strep
enterococcus
faecalis and faceium
strep pneumoniae
no gram neg cover
indications vancomycin
infections caused by sensitive oganisms - sepsis, endocarditis
SE vancomycin
nephrotoxicity
ototoxicity
neutropaenia
phlebitis
red man syndrome
SJS
TEN
ED
what bacteria does ceftazidime work on
haemophilus infuelzae
e.coli
klebsiella
pseudomonas aeruginosa
moraxella cattahalis
no grampositive
indications ceftazadime
pseudomonal infections
what bacteria does cefritaxone wotk on
staph aureus
haem strep
strep pneumoniae
neisseria meningitidis
neisseria gonorrhoea
h. influenzae
e.coli
klebsiella
moraxella cattarhalis
how does ciprofloxacin work
bactericidal, act on DNA gyrase
what bacteria does ciprofloxacin work on
staph aureus
h.influenzae
e.coli
psuedomonas aeruginosa
moraexella catarrhalis
mycoplasma pneumoniae
chlamydia
salmonella
shigella
camplylobacter
indications ciprofloxacin
atypical CAP, UTIs, GI (typhoid), osteomyelitis, septic arthritis, gonorrhoea, septicaemia
cautions ciprofoxacin
lower seizure threshold
exacerbate myasthenia gravius
can precipitate attack in G6PD deficiency
tendon rupture
avoid in children and pregnancy
SE ciprofoxacin
nausea and vom
diarrhoea
tendonitis
photosensitivity
SJS
TEN
what bacteria does trimethoprim work against
e.coli
klebsiella
shigella
salmonella
indications trimethoprim
UTI
bronchitis
shigellosis
invasive salmonella
CI trimethoprim
teratogenic in 1st trimester
what does cefuroxime work against
staph aureus
haem strep
strep pneumoniae
h.infuelzae
e.coli
klebsiella
moraxella cattarhalis
what does cefadroxil work against
staph aureus
haem strep
strep pneumoniae
e.coli
indications cefadroxil
UTIs in pregnancy
otitis media
sinusiits
skin and soft tissue infection
SE cefadroxil
diarrhoea
nause and vom
headache
SJS
TEN
bacteria benpen works agaisnt
haem strep
strep pneumoniae
enterococcus faecalis
listeria monocytogenes
clostridium perfrigens
neisseria meningitidis
infications benpen
throat infections
otitis media
endocardiits
meningococcal disease
pneumoniae
cellulitis
antrhax
intrapartum GBS
SE benpen
hypersensitivity rash
CNS toxicity
interstitial nephroitis
haemolytoc anaemia
leucopenia
thrombocytopenia
diarrhoea
bacteria metronidazole works against
anaerobes
protozoa
SE metronidazole
disulfiram like reaction with alcohol
GI upset
taste disturbance
cautions metronidazole
liver impairment
inidcations penicillin
oral infection
tonsillitis
otitis media
erysipelas
celluliits
group a strep
rheumatic fever
pneumococcal infection
indications benzathine penicilloin
syphilis
what does piptazobactam/tazocin work against
staph aureus
haem strep
enterococcus faecalis
strep pneumoniae
clostridium perfringens
bacteroides fragilis
h.influenzae
e.coli
klebsiella
psuedomonas aeruginosa
moraxella cattarhalis
indications piptazobactam/tazocin
hospital acquired pneumonia
septicaemia
peritonitis
complicated UTIS
pseudomonal infections
what do carbapenems work against
staph aureus
haem strep
enterococcus faecalis
strep pneumoniae
listeria monocytogenes
clostridium perfringens
bacterioides fragillis
neisseria meningitidis
h.influenzae
e.coli
klebsiella
pseudomonas aeruginosa
moraxella cattarhalis
indications carbapenems
severe hospital acquired infections
sepsis
intra abdo infection
skin and soft tissue infections
complicated UTIs
SE carbapenems
nausea and vom
diarrhoea
raised LFTs
headache
thrombocytopenia
what bacteria does co-amoxiclav/augmentin work on
staph aureus
haem strep
enterococcus faecalis
strep pneumoniae
clostridium perfringens
h.influenzaew
e.coli
moraxella cattarhalis
indications for co-amoxiclav
celluliits
osteomyelitis
septic arthritis
genito-urinary infections
abdo infections
severe dental infection
SE co-amoxiclav
cholestatic jaundice
SJS
toxic epidermal necrolysis
exfoliative dermatitis
vasculitis
CNS toxicity
what bcateria to ampicillin and amoxicillin work against
haem strep
enterococcus faecalis
strep pneumoniae
listeria monocytogenes
clostridium perfringens
indications ampicilin/amoxicillin
UTI
otitis media
sinusiits
bronchitis
community acquired pnuemonia
cautions ampicillin/amoxicillin
suspected glandular fever
lymphocytic leukaemia
sE ampicillin/amoxicillin
nause and vom
diarrhoea
rash
what does fluclox work against
staoh aureus
haem strep
indications fluclox
otitis externa
pneumonia
impetigo
cellulitis
osteomyelitis
endocardiitis
gram staining
POSITIVE – PURPLE
NEGATIVE - RED
ziehl neelsen staining
USED FOR MYCOBACTERIA
THEY ARE ACID FAST – PINK/RED
What does acid fast mean?
THIS MEANS THAT THEY RESIST ACID DE-COLOURISATION PROCEDURES
catalase tests
TELLS YOU THE DIFFERENCE BETWEEN:
STAPHYLOCOCCI
STREPTOCOCCI/ENTEROCOCCI
staphylococci use catalase to protect against hydrogen peroxide – reaction you see bubbles – catalase positive
if not present there is no reaction – catalase negative
coagulase test
Used to differentiate between:
Staphylococcus aureus
Other Staphylococci
COAGULASE is an enzyme that causes coagulation – fibrin to clot
BACTERIA + PLASMA = CLOT - STAPH AUREUS – coagulase positive
BACTERIA + PLASMA = NO CLOT – OTHER STAPH SPEICES – coagulase negative
oxidase test
Identifies bacteria that are oxidase positive – produce cytochrome oxidase
Pseudomonas
Neisseria
POSITIVE TEST RESULT – BLACK/PURPLE COLOUR
NEGATIVE TEST RESULT – NO COLOUR CHANGE
optochin test
Differentiates:
Streptococcus pneumoniae – what type of cocci…
Diplococci in chains
From other alpha haemolytic streptococci
Clear zone of lysis – strep. pneumoniae
blood agar
Differentiates
Alpha haemolytic streptococci
Beta haemolytic streptococci
Alpha – green pigment
Beta – clear zones of lysis
Non-haemolytic – no change
macconkey agar
Bile salts only permit the growth of enteric bacteria
Lactose fermentation causes an acidic environment – red/pink colour change with the indicator
Red/pink colony – E Coli, Klebsiella
Clear colony – Salmonella, Shigella, Pseudomonas
gram positive aerobic bacilli
cornybacterium: c.diptheria
listeria: listeria monocytogenes
bacilus: b. anthracis, b.cerus
gram positive anaerobic bacili
clostridium
gram positive alpha haemolytic strep
s.pneumoniae
s.oralis
s.sanguis
gram positive beta haemolutic strep
s. pyogenes (A)
s. agalactiae (B)
gram positive non haemolytic strep
s.mutans
s.milleri
enterococcus faecalis (D)
gram positive coag negative staph
s.epidermidis
s. saprophiticus
gram positive coag posiitve staph
s.aureus
gram negative bacilli aerobic lactose fermenters (macConkey pink)
e.coli
K.pneumoniae
gram negative aerobic non lactose fermenters bacili
salmonella: s.typhi, s.paratyphi, s.enterica
shigella: s.sonnei, s.dysenteriae
proteus: p.mirabilis
gram negative cocci
n.meningitidis, n.gonorrhoea
moraxella catarrhalis
gram negative aerobic bacili with fastidious growth requirements
parvobacteria: h.influenzae, bordatella pertussus, legionella pneumophilia, brucella, campylobacter jejuni
helicobacter pylori
obligate intracellular bacteria
chlamydia
coxiella
rickettsia
ziehl neelson positive bacteria
mycobacteria
spirochaetes
treponema pallidum
borrelia
leptospira
exotoxin
secreted by bacteria (MAINLY GRAM POSITIVE) – specific actions – like paralysis with botulinum toxin
endotoxin
– released when bacteria is damaged, less specific action – septic shock
TB mx
Rifampicin - RED urine, hepatotoxicity
Isoniazid – peripheral neuropathy – N for neuropathy
Pyrizinamide - hepatotoxicity
Ethambutol – ocular/EYE toxicity
UTI causes
E Coli
Other causative organisms
Proteus
Klebsiella
mx UTI
First line
Trimethoprim/nitrofurantoin
Or amoxicillin
cause pyelonephritis
E Coli
Other causative organism
Enterococcus faecalis
mx pyelonephritis
Use cefuroxime or quinolone (floxacin – ciprofloxacin)
Gentamicin
cause prostatitis
E Coli
But also
Proteus Mirabilis
Klebsiella
mx prostatitis
Quinolones (ciprofloxacin)
cause imptigo
s.aureus
mx impetigo
fusidic acid
cause celullitis
s.aureus
mx cellulitis
fluclox
cause resp pneumonia
Strep Pneumonia
Other causes
H Influenzae
Atypicals –
Coxiella, Chlamydophilia, Mycoplasma, Leigionella
mx CAP
Low severity=Amoxicillin
Moderate=Amoxicillin
High severity=Benzylpenicillin + clarithromycin (why clarithromycin?)
mx HAP
Co-amoxiclav – if early onset (less than 5 days into admission)
Tazoin – if late onset (more than 5 days)
cause osteomyelitis
S Aureus
Other=Enterocbacter
Streptococcus
if sickle cell anaemia=Salmonella
mx osteomyelitis
fluclox
cause septic arthritis
S Aureus
Other
Streptococci
Neisseria – in sexually active young adults
mx septic arthritis
fluclox
cause eye infections
S Aureus
Other causes
Streptococci
Haemophilus
mx eye infections
Chloramphenicol
tx c.diff
Metronidazole – use in situations where anaerobic bacteria are suspected
cause meningitis
Neisseria Meningitidis
Streptococcus Pneumoniae
mx meningitis
3 months -50 years=Cefotaxime
Over 50 years=Cefotaxime and amoxicillin
what type of diarrhoea does cholera cause
rice water
Abx that work by affecting folate (nucleic acid synthesis)
Sulfonamides
Trimethoprim
Abx that affect DNA gyrase (nucleic acid) synthesis
Quinolones
Abx that affect RNA polymerase synthesis (nucleic acid synthesis)
Rifampicir
Abx that affect cell wall synthesis
Beta lactams
Vancomycin
Bacitracin
Cell membrane synthesis: polymyxins
Beta lactams
Penicillins
Cephalosporins
Carbapanems
Monobactams
Abx that affect 50 s subunit (protein) synthesis
Macrolides
Clindamycin
Linezolid
Chloramphenicol
Streptogramins
Abx that affect 30s ribosome (protein) synthesis
Tetracycline
Aminoglycosides
Where does first pass metabolism happen
Liver
Drugs that increase risk c diff
Abx: c drugs
Ciprofloxacin
Clindamicin
Cephalosporin
Co amox
Carbapenems
Antibiotics stewardship
Start smart: only start if clinical evidence, comply with local guidelines, document clinical indication and when to rev, cultures before start
Focus: after 48-72h: stop if no infection, IV to oral, narrow the spectrum, continue and document review/start date, outpatient parenteral abx if still need
What to write in exam if unsure which abx
Give antibiotics as per local guidelines (name of drug in brackets if know)
Ciprofloxacin SE
REDUCES seizures threshold
Increases QT interval
Predisposes to Aortic dissection
C. Diff
Tendo rupture
What to NEVER prescribe with trimethoprim
Methotrexate
When to avoid nitrofurantoin
If eGFR less than 45 as its really excreted so won’t work
Abx for hospital acquired pneumonia sheffield
If well: doxcycycline
Unwell: tazocin (piperacillin/tazobactam)
Severity markers c diff and what do if present
WCC high, AKI, abdominal pain, fever over 38.5
Call surgeons, query colitis
Mx c. Diff
Oral vancomycin
Fidaxomicin second line (due to costs)
Which abx SE is red man syndrome
Vancomycin infusion
Red man syndrome sx
pruritus
an erythematous rash that involves the face, neck, and upper torso. Less frequently, hypotension and angioedema can occur.
Blood Borne virus screen
HIV
hep B
Hep C
