1
Q
Class side effect of carbapenem
A
Some neurotoxicity
2
Q
only BETA LACTAM active against MRSA
A
ceftaroline
3
Q
Does vancomycin require dosage adjustment in renal impairment or hepatic impairment? WHYYYYYYY?
A
renal impairment.
75% of drug excreted unchanged in urine. renal impairment will affect PK of drugs and require dosage adjustment
4
Q
Is vancomycin renally cleared or hepatically cleared?
A
Renally cleared
(and hence requires renal adjustments)
(it is also nephrotoxic)
(i also dont want to study anymore)
5
Q
co-trimoxazole is time/concentration/AUC dependent killing?
A
concentration dependent killing
6
Q
spectrum of activity for co-trimoxazole
A
susceptible to enterobacterales (E. coli, klebsiella, proteus)
yellow for MRSA, MSSA, strep pneumo, H. influenzae, ESBL-producing and AmpC-type
7
Q
main indication for co-trimoxazole
A
mostly used in UTI
(more for UTI in men but local resistance to co-trimoxazole is quite high so yellow susceptibility)
8
Q
main elimination pathway for sulfamethoxazole and trimethoprim
A
sulfamethoxazole - renal elimination + hepatic metabolism
trimethoprim - renal elimination mainly
9
Q
contraindications to co-trimoxazole (& reasons)
A
- severe hepatic/renal impairment (due to elimination)
- pregnancy (both, due to possible folate deficiency, and can cross placenta)
- infants (sulfo, risk of kernicterus due to displacement of bilirubin from serum albumin)
- history of co-trimoxazole induced thrombocytopenia (dont want to risk this again)
- existing folate deficiency induced megaloblastic anemia (already deficient and anemic, dont want to worsen)
10
Q
monitoring parameters for co-trimoxazole & reasoning
A
- CBC with differential (hematological disorders)
- LFT & RP (renal and hepatic function)
- Serum K (K-sparing diuretic - trimethoprim)
- Urine (in case of crystalluria due to sulfamethoxazole)
- Allergy reactions (in case of hypersensitivity)
11
Q
Difference between MOA for linezolid VS macrolide/clindamycin
A
linezolid is a protein synthesis inhibitor that binds to 50s ribosomal subunit near INTIATOR COMPLEX SITE
macrolide/clindamycin: it binds to 50s ribosomal subunit near PEPTIDYL TRANSFER SITE
12
Q
spectrum of activity for linezolid
A
gram positive & some anaerobes
subjected to efflux in gram negative (no gram neg coverage)
13
Q
common use of linezolid
A
against MRSA in SSTIs (either vancomycin/linezolid)
14
Q
Can I use linezolid with paroxetine/venlafaxine?
A
No, risk of serotonin syndrome. Should not use linezolid with MAOi/SSRIs/SNRIs/Serotonin agonists. Avoid tyramine-rich food.
15
Q
elimination pathway for linezolid
A
hepatic metabolism > renal excretion
–> caution in severe impairment
16
Q
monitoring parameters for linezolid
A
- CBC with differential (hematological disorders)
- fingertip numbness/tingling/weaknes & eyesight changes (due to potential irreversible peripheral neuropathy/optic neuritis with >28days of use)
17
Q
how to prevent crystalluria for co-trimoxazole
A
take with water and hydrate regularly
18
Q
spectrum of activity for clindamycin
A
gram pos and anaerobes (intrinsic resistance by gram neg and c diff)
local resistance to clindamycin quiet high.. so all gram pos yellow except
enterococcus faecalis & C diff.
ONLY GREEN FOR gram pos anaerobe (finegoldia magna)
19
Q
elimination pathway of clindamycin
A
hepatic metabolism»_space;> renal excretion
–> caution in severe liver impairment (and maybe severe renal impairment)
–> monitor liver function
20
Q
contraindications of clindamycin
A
pseudomembranous colitis (like in C diff infection), ulcerative colitis or any colonic inflammation
21
Q
monitoring parameters for clindamycin
A
- Liver function (major elimination pathway)
- changes in bowel frequency / colitis (monitor for colonic inflammation)
22
Q
Why does metronidazole only target anaerobes (so well)
my favourite antibiotics <3
少给我麻烦 <3
A
metronidazole has cytotoxic free radicals that cause protein and DNA damage which requires strong reducing conditions (aka anaerobic cnditions)
23
Q
common side effect of metronidazole for PO
A
unpleasant, metallic taste
24
Q
elimination pathway of metronidazole
A
(BOTH)
hepatic metabolism + renal excretion.
caution in renal/hepatic impairment, may need dose adjustment in severe hepatic impairment
25
monitoring parameters for metronidazole
- liver function (major elimination pathway)
- neurological symptoms (eyesight changes, fingertip numbness/weakness, seizures, mental state) (due to CNS/PNS ADR such as convulsive seizures, optic and peripheral neuropathy, confusion. vertigo, hallucinations)
26
DDI and DFI with metronidazole
- warfarin (increase PTT & INR)
- disulfiram
- alcohol (disulfiram-like reaction with alcohol intake)
27
Antibiotics used to treat CNS infection (6)
penicillin
ceftriaxone
cefepime
ceftazidime
meropenem
vancomycin
28
first line therapy for TB (4+1)
- rifampicin
- isoniazid
- pyrazinamide
- ethambutol
- streptomycin
29
for latent TB, what is the regimen?
single agent therapy
- 4mth rifampicin OR
- 6mth isoniazid
30
standard regime for active TB
(2RIPE/4RI)
intensive phase: 2 months x RIPE OD
continuous phase: 4 months x RI OD/3X/WEEK
31
role of streptomycin as part of first line TB therapy
May sometimes replace ethambutol in intensive phase due to lower frequency of acquired resistance
32
how to determine cure of TB?
>=2x negative smears/culture (negative in the last month + >=1 other occasion)
failure = postive @ or after 5 months
33
monitoring parameters before starting TB therapy and during TB therapy.
before starting:
- baseline AST&ALT (ensure baseline liver function)
- weight
- vision acuity and colour vision check due to ocular toxicity risk by EMB
during therapy:
- monitor LFT if high risk for hepatic toxicity
- weight
- monitor for drug-induced hepatotoxicity
34
hepatotoxicity in drugs from high to low
PZA > INH > RMP
35
renal dosage adjustment in which TB drugs?
PZA & EMB - mainly renal excretion especially for <30ml/min
Streptomycin - reduce dose in impairment + nephrotoxic risk (aminoglycosides class effect)
36
4 steps for the antimicrobial approach
1. confirm presence of infection
2. identify likely pathogen
3. select antimicrobial regimen
4. monitor response & plan
37
What do you look for to confirm presence of infection?
- risk factors of patient
- subjective evidence
- objective evidence
- possible site of infection
38
Common sites of infection
Blood, Respi, GIT (intra-abdominal), SSTI, UTI
39
abnormal vital signs -
temperature:
BP:
HR:
RR:
mental:
temperature >=38.0degC
SBP < 100mmHg (may also need to observe baseline, patient's normal BP trend)
HR > 90bpm
RR > 22bpm
mental: drop in Glasglow coma scale
40
abnormal labs:
Whites
Neutrophils
C-reactive protein
Erythrocyte sedimentation rate
- elevated (14-15) or depressed (2-3) x 10^9/L (normal is 4-10x10^9/L) white count
- ~90% neutrophils (observe trend; normal is 45-75%)
- infection CRP > 40mg/L
- increased ESR for bone and joint inflammation
41
how does procalcitonin aid in clinical diagnosis?
Guides starting/continuation of Abx in patients.
<=0.25mcg/L usually strongly discourages antibiotics
0.25-0.5 is discouraged also
above is more encouraged, if it increased or >1mcg/L, strongly encourage abx
42
Which groups of patients can have elevated procalcitonin without infection (and should take note)?
- traumatic brain injury (TBI)
- ESRF (procalcitonin cleared by kidneys, accumulation due to ESRF is possible)
43
In patients with G6PD deficiency, what antibiotics should they avoid?
Sulfonamide, nitrofurantoin, older generation fluoroquinolone
44
Antibiotic with no shared side chain as penicillins (can consider in penicillin allergy)?
Cefazolin
45
Abx classes generally SAFE in pregnancy & lactation
beta-lactams and macrolides
46
Abx classes generally CAUTIONED in pregnancy & lactation
co-trimoxazole, fluoroquinolones, tetracyclines
47
Nephrotoxic Abx
aminoglycosides, high dose vancomycin, amphotericin B
48
Hepatotoxic Abx
pyrazinamide, amoxicillin-clavulanate
49
Bactericidal drugs (better to use for immunocompromised patients)
beta-lactam, (fluoro)quinolones, aminoglycosides, vancomycin
50
Why is daptomycin not used in respiratory infections?
Daptomycin gets destroyed by lung surfactant
51
Why are ciprofloxacin and co-trimoxazole drugs of choice for prostatitis?
They distribute well to the prostate
52
Common bacteriostatic antibiotics (inhibit protein synthesis)
- macrolides
- tetracyclines
- trimethoprim & sulfonamides
53
Common CYP3A4 inhibitors
NDHPCCB - veramapil, diltiazem
azole antifungals - itraconazole, ketoconazole
macrolide antibiotics - clarithromycin, erythromycin
antiHIV - ritonavir, saquinavir
54
common CYP3A4 inducers
rifampin/rifampicin
HIV NNRTIs - efavirenz
55
Which antibiotics can cause QTc prolongation?
Macrolides - clarithromycin, erythromycin
Fluoroquinolons - levofloxacin, ciprofloxacin
azoles - itraconazole, etc
56
Which abx can cause photosensitivity?
tetracycline (doxycycline), sulfonamides, quinolones
57
Which conditions predisposes infections?
DM, cirrhosis, neutropenia, HIV, transplant&immunosuppressive medications
58
In SSTIs which bacteria infection commonly presents with pus?
Staphylococcus aureus
59
common pathogens for impetigo
staphylococci/streptococci
bullous form - toxic strains of S. aureus
mainly looking at MSSA
60
common pathogens for ecthyma
most frequently caused by group A streptococci
61
Regimen for mild, limited lesions in impetigo
topical mupirocin BD x 5days
62
What's the concern for topical mupirocin?
Increasing resistance to mupirocin since it's used to decolonise MRSA in hospitals
63
Empiric treatment for impetigo/ecthyma & duration
& if penicillin allergy
PO cephalexin or cloxacillin for 5-7days
penicillin allergy: PO clindamycin or non cross reacting B-lactams (cefazoline, cefuroxime)
(dont have to consider MRSA since CA-MRSA is not common in SG)
64
In purulent lesions (furuncle, abscess, carbuncles, purulent cellulitis), what are the common pathogens?
- mainly by S. aureus (purulence)
- some beta-hemolytic streptococci (:o blood agar plate?!?!?)
- multiple organisms incl gram neg & anaerobes in abscess involving perioral/perirectal/vulvovaginal areas
65
Mild purulent SSTI treatment
Incision & drainage
Warm compress to promote drainage
66
Moderate (with systemic symptoms) purulent SSTI treatment
Incision & Drainage + ORAL antibiotics
PO cephalexin or cloxacillin
penicillin allergy: clindamycin
for 5-10days
67
Severe purulent SSTI treatment
Incision & Drainage + IV antibiotics
IV cefazolin or cloxacillin
penicillin allergy: clindamycin OR vancomycin
for 5-10days
68
Mrs T has a purulent skin abscess in the vulvovaginal area. She presents with temperature of 38.4degC and malaise. She does NOT have a penicillin allergy.
What should her treatment be?
PO Amoxicillin-clavulanate for 5-10days
(potentially gram neg / anaerobes infection due to abscess being in vulvovaginal area)
69
In nonpurulent infections (cellulitis, erysipelas), what are the common pathogens?
- mainly beta-hemolytic streptococcus
- usually group A strep ^
- SA less common
- with water exposure: aeromonas, pseudomonas, vibrio
70
In nonpurulent infections (cellulitis, erysipelas), what antibiotic can cover for aeromonas, pseudomonas and vibrio if lesion has been exposed to water?
Ciprofloxacin
71
Mild nonpurulent infection treatment & duration
mainly only cover strep pyogenes, ORAL abx
PO Penicillin V, cloxacillin, cephalexin for 5-10days
penicillin allergy: clindamycin
72
Moderate (w systemic signs/mildly purulent) cellulitis/erysipelas treatment & duration
strep pyogenes + MSSA cover, may IV
PO/IV cloxacillin, cephalexin/cefazolin for 5-10days
penicillin allergy: clindamycin
73
Severe (systemic signs, failed PO therapy OR immunocompromised) cellulitis/erysipelas treatment & duration
BROADER COVERAGE (all v broad spectrum abx)
IV piperacillin-tazobactam, cefepime, meropenem for 5-10days
74
What abx to add on when there is MRSA risk factors?
aka MRSA colonisation, previous Abx use, previous hospitalisation, etc
IV vancomycin, daptomycin or linezolid
Daptomycin cannot cover MRSA in respiratory infections
75
How to determine infection of diabetic foot ulcers/pressure ulcers?
Purulent discharge OR
>= 2 signs of inflammation: red, swelling, warm, tender, pain, induration (hardness/scabbing)
76
Common causative organisms for DFI
- Staphyloccocus aureus & streptococcus spp most common
- gram negative enterobacterales if in chronic wounds/prev treated with Abx
- PsA less common, but possible (esp w water exposure)
- anaerobes in hypoxic wounds (ischemic/necrotic wounds)
77
Mild DFI
Definition -
What to cover -
Antibiotics to use -
Definition:
Infection of skin and/or SC tissue + erythema <=2cm around ulcer + no systemic signs
What to cover:
Staph aureus + Strep pyogenes
Antibiotics to use:
PO cephalexin, cloxacillin, clindamycin (penicillin allergy)
MRSA risk factors - PO doxycycline, co-trimoxazole, clindamycin
78
Moderate DFI
Definition -
What to cover -
Antibiotics to use -
Definition:
Infection of deep tissue (bone/joint) OR erythema >2cm around ulcer
+ no systemic signs
What to cover:
Staph aureus + strep pyogenes + gram neg (+/- PsA) + anaerobes
Antibiotics to use: (Initial IV)
- amoxicillin-clavulanate (all except PsA)
- cefazolin/ceftriaxone (gram negs, gram pos, no anaerobes) + metronidazole (anaerobes)
MRSA risk factors - IV vancomycin/daptomycin/linezolid
79
Severe DFI
Definition -
What to cover -
Antibiotics to use -
Definition:
Infection of deep tissue (bone/joint) OR erythema >2cm around ulcer
+ YES systemic signs
What to cover:
Staph aureus + strep pyogenes + gram neg (incl PsA) + anaerobes
Antibiotics to use: (initial IV)
- piperacillin-tazobactam
- meropenem
- cefepime (gram neg, gram pos, no anaerobes, YES PSA) + metronidazole (anaerobes)
- ciprofloxacin (gram negs, YES PSA) + clindamycin (gram pos, if penicillin allergy)
MRSA risk factors - IV vancomycin/daptomycin/linezolid
80
Duration of therapy for DFI with NO BONE INVOLVEMENT
Mild - 1-2weeks
Moderate - 1-3 weeks
Severe - 2-4 weeks
generally takes longer than other infection, bacteria may be harder to clear
81
Which 2 groups of patients to screen for asymptomatic bacteriuria (ASB)?
1. pregnant women - prevent pyelonephritis, low infant birth weight and preterm labour
2. patients going for invasive urologic procedure in which trauma/bleeding is expected - prevent bacteremia and urosepsis
82
4 natural defense mechanisms of the urinary tract
- Micturition (peeing) with increased diuresis stimulated by bacteria→ empty bladder
- Antibacterial properties of urine & prostatic secretion
- Anti-adherence mechanism to prevent bacterial attachment to the bladder
- Inflammatory response with neutrophils (neutrophils camp in the cells there and ready to attack) → phagocytosis
83
How to prevent more UTIs? Non-pharmacological suggestions
- drink lots of fluid to flush bacteria (pee more, flush more)
- urinate frequently and whenever you feel the urge (不要忍，不要憋，不要尿道管发炎！）
- urinate shortly after sex (flush away bacteria that may have entered urethra during sex)
- wipe from front to back, especially after bowel movement (大便）(for women)
- wear cotton underwear and loose fitting clothes to keep area dry. tight clothes trap moisture and help bacteria grow
- using diaphragm or spermicide can lead to UTI > may want to modify birth control method
84
Mrs T (again) is on birth control by using a diaphragm since she does not want to have kids now (拼事业，什么是组织家庭？？？？）but anws, her sexual activity with her husband (only sexual partner) is regular. Her past medical history includes Type 2 Diabetes Mellitus and allergic rhinitis.
She recently renovated her house and is currently on chlorpheniramine to help with her allergic rhinitis symptoms.
What are her risk factors for UTI?
- female
- diaphragm birth control
- sexual intercourse
- diabetes
- anticholinergic drug
10/10 ready to get a UTI!!!
85
Subjective symptoms in lower UTI (cystitis)
Dysuria
urgent
frequent
nocturia
suprapubic heaviness or pain
gross hematuria (blood in pee)
86
Subjective symptoms in upper UTI (pyelonephritis)
Fever, rigors, headache, N/V, tiredness, flank pain (press and lower back hurts), costovertebral tenderness (renal punch - done by doctor), abdominal pain
87
Common pathogens for ASCENDING UTI (from UT to pyelo or bacteremia)
Gram negative enterobacterales: E coli, klebsiella, proteus
88
Common pathogens for DESCENDING UTI (from blood to UT)
staphylococcus aureus, mycobacterium TB
89
2 chemical tests for UTI
1. nitrites - positive test indicates gram negative bacteria
2. leukocyte esterase test - positive test = WBC in urine (pyuria)
90
Urine cultures are not needed in uncomplicated cystitis, but which groups patients may require pre-treatment culture?
- pregnant women
- recurrent UTI within 2 weeks/frequent
- pyelonephritis
- catheter-associated
- Men with UTI
91
Likely pathogen in community-acquired/uncomplicated UTI
- E coli (~85%) - gram neg
- staphylococcus saprophyticus (5-15%) - gram pos
- enterococcus faecalis (+), klebsiella, proteus
92
Likely pathogen in healthcare-associated UTI
- Ecoli (~50%)
- enterococci (+)
- proteus, klebsiella, enterobacter, PsA
93
First line empiric therapy for uncomplicated cystitis
Nitrofurantoin for 3-5 days
94
Second line empiric therapy for uncomplicated cystitis
1. Fosfomycin 3g single dose
- contraindicated in CrCl < 10ml/min
- SE includes heartburn
2. amoxicillin-clavulanate (augmentin 1g for severe cases, 625mg for mild-moderate)
- contraindicated in history of amox-clav associated hepatic dysfunction or jaundice
- SE includes mucocutaneous candidiasis
95
Why is nitrofurantoin and fosfomycin not used in men with UTI?
Nitrofurantoin and fosfomycin do not distribute well to the prostate (unlikely to reach therapeutic levels)
96
Why is co-trimoxazole an alternative in cystitis?
Local resistance to co-trimox is quite high. Culture before giving abx and monitor after giving co-trimox.
3days for treatment, 7days in men
97
First line empiric therapy for uncomplicated pyelonephritis
Amoxicillin-clavulanate 825/125mg (Augmentin 1g) BD x 10-14days (higher dose and longer than cystitis)
- contraindicated in history of amox-clav associated hepatic dysfunction or jaundice
- SE includes mucocutaneous candidiasis
98
Second line empiric therapy for uncomplicated pyelonephritis
Cefuroxime axetil (2nd gen cephalosporin) x 7-10 days
- SE includes abdominal pain
- cross reactivity with penicillin is unlikely, but still use with caution
- effectiveness reduced by increase in gastric pH (DDI: PPIs, antacids, H2RA) --> administer Abx 1h before or 2h after
99
Good abx to use for UTI when ASTs are available (3)
- ciprofloxacin x 7 days
- levofloxacin x 5 days
- co-trimoxazole x 7/14 days
100
Why is amoxicillin not used for UTI?
Local resistance of E coli to amoxicillin is 40-50% (too high already)
101
In complicated pyelonephritis/UTI, what empiric therapy to use?
(need IV liao ah,,,)
duration of therapy:
NO MDRO risk factors:
MDRO risk factors:
duration of therapy: 7-14days (14d for men!!, that's kinda L if u ask me)
NO MDRO risk factors - cover E coli and proteus
- amoxicillin-clavulanate 1.2g OR ceftriaxone
+/- gentamicin 5mg/kg to cover for ESBL producing/AmpC type (distributes well to urine and kidney)
MDRO risk factors - cover ESBL-producing E coli&klebsiella, proteus, PsA
- Cefepime (incl PsA, may not be effective against ESBL-producing Klebsiella) +/- amikacin 15mg/kg/day (cover ESBL producing Klebsiella)
- piperacillin-tazobactam (okok coverage for ESBL in urine) OR meropenem OR imipenem
102
Why are nitrofurantoin and fosfomycin not used in complicated pyelonephritis?
Does not distribute well to renal parenchyma
103
Mrs T is now pregnant (guess her birth control is useless lolsies). And SHE GOT UTI!!!
What antibiotics should be avoided for her and which can be used?
YES:
- beta-lactams (generally safe in pregnancy) aka amoxicillin-clavulanate (best choice)
- fosfomycin: if cystitis then ok
NO:
- ciprofloxacin (fetal risk cannot be ruled out)
- co-trimoxazole in 1st and 3rd trimester (1st trimester - folate antagonism can cause neural tube defects; 3rd tri - risk of kernicterus due to sulfamethoxazole)
- nitrofurantoin @ term (38-42 weeks) (concern that fetus will be G6PD deficient)
104
Duration of therapy for catheter-associated UTI
7 days with prompt resolution (no fever in 72h) or 10-14 days for delayed response
105
Does influenza have high or low grade fever?
High
106
Common pathogens for common cold
rhinovirus, coronavirus
107
Common pathogens for Influenza
Influenza A and B
108
How fast should I initiate influenza antiviral?
Who should be started on antiviral?
aka oseltamivir
best within 48h, up to 5 days
For people who are hospitalised/high risk of complications/severe, complicated or progressive illness
109
How to tell if pharyngitis is bacterial?
Sore throat with tonsillar exudates, fever, swollen lymph nodes WITHOUT viral symptoms (runny nose, etc)
110
Common pathogen for bacterial pharyngitis
Group A beta-hemolytic streptococcus (S. pyogenes)
111
Modified centor criteria is a list of criteria to determine if a patient has strep pharyngitis.
What are the components of this criteria?
What is the diagnosis for each number of points (max 6)?
- fever >38.0degC
- swollen lymph nodes
- tonsillar exudates
- absence of cough
- age (+1 if 3-14, -1 if above 45)
0-1 points - presumed viral, no Abx required
2-3 points - test for strep pharyngitis, Abx if positive
4-5 points - high risk of Strep pharyngitis, initiate empiric Abx
112
Empiric first line therapy for bacterial pharyngitis
+ penicillin allergy & their concerns
+ duration of therapy
First line:
PO Amoxicillin 500mg Q12H
PO Penicillin 250mg Q6H
(amox-clav too broad, no need)
Penicillin allergy:
if not severe - PO cefuroxime
else:
- PO azithromycin
- PO clarithromycin
- PO Clindamycin
(concerns of QTc prolongation)
Duration of therapy: 10 days (5 days for azithromycin)
113
How do bacteria invade body system when a patient has viral rhinosinusitis?
Inflammation obstruct sinuses and trap nasal secretions inside the nose --> bacteria also get trapped and have the chance to proliferate
114
Symptoms suggestive of orbital cellulitis/CNS involvement which warrants referral to ED in acute rhinosinusitis
- limited ocular movements
- acute vision changes
- confusion
- unilateral weakness
115
Most common pathogens for acute bacterial rhinosinusitis
Streptococcus pneumoniae
Haemophilus influenzae
116
How to differentiate between anaerobic bacteria?
Above diaphragm - gram positive anaerobe > finegoldia, susceptible to beta lactams
Below diaphragm - gram negative anaerobe > B fragilis, require specific Abx
and there is the problem child: C diff
117
When to initiate Abx treatment for bacterial rhinosinusitis?
1. Persistent symptoms beyond 10 days with no clinical improvement
2. Symptoms worsen
3. Symptoms clinically improvement for >=3 days but gets worse again (double sickening)
118
First line treatment for bacterial sinusitis
+ penicillin allergy
+ duration of treatment
Amoxicillin 500mg Q8H
Amoxicillin-Clavulanate 625mg Q8H (improved susceptibility of H influenzae in case of resistance)
Penicillin allergy:
- non severe - PO cefuroxime
- PO Levofloxacin 500mg or moxifloxacin 400mg OD
Duration of therapy: 5-7days
119
Which group of patients should be recommended pre-treatment blood and respi gram stain and cultures in pneumonia (CAP)?
Severe CAP
Risk factors for Drug resistant pathogens (MRSA, PsA) aka empirically treated for MRSA/PsA OR previously infected with MRSA/PsA in past 1 year OR Hospitalised/received parenteral abx in last 90 days
120
Key pathogens in outpatient and inpatient non severe CAP cases
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypical (Legionella, Mycobacterium, Chlamydophila pneumoniae)
- inpatient: MRSA and PsA risk factors
121
Key pathogens in inpatient severe CAP
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypical (Legionella, Mycobacterium, Chlamydophila pneumoniae)
- Staphylococcus aureus
- Gram negative bacilli (Klebsiella pneumoniae)
*** Burkholderia pseudomallei
- inpatient: MRSA and PsA risk factors
122
What is involved in CURB-65 criterion for CAP severity?
Confusion (new onset)
Urea > 7mmol/L
Respiratory rate >= 30 breaths/min
Blood pressure (<=90mmHg or <=60mmHg)
>= 65 years
0-1: outpatient
2: inpatient
>=3: inpatient, consider ICU
123
How to determine Severe CAP? by IDSA/ATS
>= 1 major criterion OR >= 3 minor criterion
Major:
- mechanical ventilation
- septic shock requiring vasoactive medications to maintain BP
Minor:
- RR>=30bpm
- PaO2/FiO2 <= 250
- multilobar infiltrates
- confusion/disorientation
- uremia (urea>7mmol/L
- leukopenia (WBC < 4x10^9/L)
- hypothermia (<36degC)
- hypotension requiring aggressive fluid resuscitation
124
First line outpatient CAP treatment
ALL PO ABX
No comorbidities: (just need cover strep pneumo) Amoxicillin 1g Q8H OR respiratory FQ
with comorbidities: (cover all)
Amoxicillin-clavulanate OR cefuroxime AND
macrolide (clarithro/azithro) or doxycycline (for atypical coverage)
OR respiratory FQ - cover everyth
125
Empiric treatment for inpatient non severe CAP
same as outpatient comorbidities
Amoxicillin-clavulanate OR cefuroxime OR ceftriaxone (IV option avail in hospital) AND
macrolide (clarithro/azithro) or doxycycline (for atypical coverage)
OR respiratory FQ - cover everyth
MRSA Risk factor: (Resp isolation of MRSA in last 1 year / hospitalisation or parenteral abx use in last 90 days + positive MRSA PCR screen)
ADD ON IV VANCOMYCIN / PO/IV LINEZOLID
PsA risk factors (Resp isolation of PsA in last 1 year)
MODIFY REGIMEN to incl PsA
- Pip-taz (no atypical)
- Ceftazidime (no strep pneumo)
- Cefepime (no atypical)
- Meropenem (not good atypical)
- Levofloxacin (alone is ok! But tb….)
126
Empiric treatment for inpatient severe CAP
(cover incl SA and burkholderia - ceftazidime)
Amoxicillin-clavulanate/Penicillin G + ceftazidime + macrolide (clarithro/azithro)
OR respiratory FQ + ceftazidime
(MSSA incl in amox/clav, cefta incl burkholderia and H inf, no strep pneumo, macrolide for atypicals)
MRSA risk factors (resp isolation in last 1 year OR hospitalised/parenteral abx use in last 90 days)
ADD IV VANCOMYCIN / PO/IV LINEZOLID
PsA risk factors (resp isolation in last 1 year OR hospitalised/parenteral abx use in last 90 days)
cover PsA but ceftazidime / levofloxacin already cover
127
How to de-escalate CAP treatment after patient has stable vitals and clinical improvement?
Can stop empiric coverage for MRSA, PsA and burkholderia if pathogen is not isolated and patient is improving
128
Treatment duration for CAP
min 5 days, 7 days for suspected/proven MRSA/PsA
129
Likely pathogens for HAP/VAP
PsA
enterobacterales (ecoli, klebsiella, proteus)
Staphylococcus aureus
130
In HAP/VAP, under what conditions/risk factors should we cover MRSA?
- prior IV abx use in last 90 days
- isolation of MRSA in last 1 year
- hospitalisation in unit where >20% of S aureus are MRSA
- prevalence not known but patient high risk of mortality (need mechanical ventilation for eg)
131
When to use double antipseudomonal agent for HAP/VAP?
- risk factors for PsA (prior IV abx use in last 90 days, isolation in last 1 year, acute RRT prior VAP onset)
- hospitalisation in a unit where >10% of PsA isolates are resistant to an agent considered for monotherapy
- prevalence not known but high risk mortality
132
Why cannot use amikacin (aminoglycosides) as sole antipseudomonal agent?
Cannot reach high enough concentrations and shown to be inferior as monotherapy for PsA
monotherapy for UTI is ok tho, can reach kidney and UT
133
empiric treatment for HAP/VAP
(cover enterobacterales, PsA, staph aureus)
1. antipseudomonal beta-lactam (Pip-taz, cefepime, meropenem, imipenem, ceftazidime[no SA coverage, use only if MRSA cover is needed])
2. (if double PsA coverage) antipseudomonal FQ - levofloxacin or ciprofloxacin[no SA coverage, use only if MRSA cover is needed])
OR
amikacin (aminoglycoside) - cannot for sole agent
MRSA cover:
IV VANCOMYCIN OR IV/PO LINEZOLID (can use cefta&cipro since vanco/linezolid cover SA)
134
How to de-escalate in HAP/VAP?
Positive cultures for PsA --> cut to 1 agent
No positive cultures, keep covering for MSSA, PsA and gram neg bacilli
- go according to local antibiogram (choose those with higher susceptibility >90)
135
Duration of treatment for HAP/VAP
7 days regardless of pathogens
136
Classic triad of symptoms for bacterial meningitis
headache
backache
nuchal/neck rigidity
137
Most likely organisms in bacterial meningitis for
neonates (<1mth)
infants and children (<23mths)
children and adults (2-50)
adults (>50 year)
Neonates:
Group B streptococcus (Strep agalactiae), E. coli, Listeria monocytogenes
Infants and Children:
S. agalactiae, E coli,
Strep pneumoniae, Neisseria meningitidis
Children and adults:
S pneumoniae, N meningitidis
Adults:
S pneumoniae, N meningitidis, Listeria monocytogenes, aerobic GNR (e coli, klebsiella)
138
Empiric treatment for bacterial meningitis in
neonates (<1mth)
infants and children (<23mths)
children and adults (2-50)
adults (>50 year)
Neonates:
Ceftriaxone + ampicillin (covers Listeria)
Infants and children:
Ceftriaxone + vancomycin (increasing resistance of S pneumo to ceftriaxone, add vanco to be safe and eradicate S pneumo)
Children and adults:
Ceftriaxone + vancomycin
Adults:
Ceftriaxone + vancomycin + ampicillin
139
Treatment duration for
S pneumo
N meningitidis
L monocytogenes
S agalactiae (Group B strep)
Culture-negative
S pneumo - 10-14 days
N meningitidis - 5-7 days
L monocytogenes - more than 21 days
S agalactiae (Group B strep) -14-21days
Culture-negative - at least 14 days (may extend, see condition)
140
For which bacteria (2) is adjunctive dexamethasone therapy effective for in bacterial meningitis? + benefits
H influenzae and S pneumoniae
- less hearing loss and other neurologic sequelae
- decreased mortality in S pneumoniae
141
Close contact prophylaxis for neisseria meningitidis
preferred: rifampicin PO
other options:
- ciprofloxacin - risk of CNS toxicity (not preferred if meningitis)
- ceftriaxone IM - painful and inconvenient
142
Definition of watery diarrhoea in CDI
more than or equal to 3 stool in 24h
143
Diagnosis of CDI
presence of diarrhoea OR radiographic imaging of ileus or toxic megacolon
AND
positive stool test (only done for suspected CDI) OR colonoscopic/histopathologic evidence of pseudomembranous colitis
144
Initial episode treatment of CDI
Non severe
Severe
Fulminant
Non severe: PO fidaxomicin (but not avail in SG)
1st line: PO vancomycin 125mg QDS
2nd line: PO metronidazole 400mg TDS (gets well slower; SE is diarrhea)
Severe: PO vancomycin 125mg QDS
Fulminant: IV metronidazole 500 q8h AND PO vancomycin 500mg QDS +/- PR vancomycin 500mg QDS
symptoms should resolve in 10 days, if not extend 4 days
145
recurrent episode treatment of CDI
if was on fidaxomicin/vancomycin:
Tapered/pulsed PO vancomycin
if was on Metronidazole:
PO vancomycin 125mg QDS x 10 days
2nd or subsequent recurrence: pulse/tapered PO vancomycin or fecal microbiota transplant
146
legally notified STDs
gonorrhea, syphilis, HIV/AIDS, chlamydia, viral hepatitis
147
Gonorrhea treatment
Need to treat with chlamydia unless ruled out already
Ceftriaxone 500mg IM (give with lignocaine) (If >150kg, give 1g) single dose
for CHLAMYDIA: doxycyline 100mg BD x 7 days
alternate:
Gentamicin 240mg IM single dose + azithromycin 2g PO single dose (for chlamydia)
& also cefixime but not avail in sg
148
Chlamydia treatment
doxycycline 100mg BD x 7 days
alternative/less-adherent option: azithromycin 1g PO single dose
alternative: Levofloxacin 500mg PO OD x 7 days (ONLY FQ that can be used; caution in monotx for TB)
149
Syphilis treatment in:
- Primary, Secondary or early latent (<1 year)
- unknown duration/late latent infection/tertiary
- neurosyphilis
Primary, Secondary or early latent (<1 year):
IM benzathine Penicillin G 2.4 MU x 1 dose
alternative: PO doxycycline 100mg BD x 14 days
unknown duration/late latent infection/tertiary:
IM benzathine penicillin G 2.4 MU once a week x 3 dose
OR
PO doxycycline 100mg BD x 28 days
Neurosyphilis:
IV crsytalline penicillin G 3-4 MU Q4H OR 18-24million units/day continuous infusion
OR
IM procaine penicillin 2.4 MU OD + PO Probenecid 500mg OD x 10-14 days
OR
IV/IM ceftriaxone 2g OD x 10-14days
150
Benefits of PO acyclovir and valacyclovir as antiviral treatment for genital herpes?
- Reduce viral shedding (by 7 days)
- Reduce duration of symptoms (by 2 days)
- Reduce time of healing of 1st episode (by 4 days)
- Inhibits viral DNA polymerase → inhibits DNA synthesis and replication
151
First episode genital herpes treatment
- PO acyclovir 400mg TDS x 7-10days OR IV 5-10mg/kg Q8H x 2-7days if severe
- PO valacyclovir 1g BD x 7-10days
maintain adequate hydration to prevent crystallisation in renal tubules.
main SE: headache
152
Chronic suppressive therapy options for genital herpes
- PO acyclovir 400mg BD
- PO valacyclovir 500mg OD (maybe less effective)
- PO valacyclovir 1g OD
- famciclovir (not avail in sg)
153
Episodic therapy options for genital herpes
Acyclovir 800mg PO BD x 5 days OR
Acyclovir 800mg PO TDS x 2 days OR
Valacyclovir 500mg PO BD x 3 days OR
Valacyclovir 1g PO OD x 5 days
need to initiate within 1 day of symptom onset, best during prodrome period
154
Measurement of surrogate markers in HIV/AIDS
- viral load
before initiation of therapy and within 2-4weeks (not more than 8)
and every 4-8 weeks until suppressed viral load
stable patients: can measure every 3-6months or longer
- CD4 count
measure @ baseline and every 3-6months after start treatment & every 12 months after adequate response (aka CD4 between 50-150 in first year of therapy)
155
HIV/AIDS meds (4)
- Biktarvy (3in1) – bictegravir (INSTI) + tenofovir (NRTI) + emtricitabine (NRTI)
- Dolutegravir (INSTI) + tenofovir + emtricitabine
- Triumeq (3in1) – dolutegravir + abacavir (NRTI) + lamivudine (NRTI)
- Dovato (2in1) – dolutegravir + lamivudine → only for individuals w HIV RNA < 500,000copies/ml + no evidence of Hep B coinfection
PR3151
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