ID II - BACTERIAL INFECTIONS

skin flora

staph

strep

when do you infuse most pre-op abx?

w/in 60 mins before first incision

when do you infuse FQ or vanco pre-op?

120 mins before first incision

cardiac, orthopedic, or vascular surgeries: preferred abx

cefazolin

sometimes cefuroxime

cardiac, orthopedic, or vascular surgeries: abx if pt has a beta-lactam allergy

clindamycin

vancomycin

when do we use vancomycin pre-op?

• MRSA colonization or risk present

• alternative if pt has a beta-lactam allergy

what kind of bacteria are we worried about for pre-op GI surgeries?

• skin flora

  • staph and strep

• GI flora:

  • gram- rods: e coli, klebsiella

  • gram- anaerobes: bacteroides fragilis

GI pre-op abx regimens

• cefazolin + metronidazole

• cefotetan

• cefoxitin

• unasyn

meningitis sx

• fever

• headache

• stiff neck (nuchal rigidity)

• AMS

how do you diagnose meningitis?

lumbar puncture with CSF analysis

what is meningitis most commonly caused by?

a. bacteria

b. viruses

b. viruses

when meningitis is bacterial, what are the common pathogens?

• neisseria meningitidis

• strep pneumoniae

• h influenzae

when do we worry about listeria with meningitis?

• neonates

• age > 50 years

• immunocompromised

how long do you treat meningitis caused by n meningitidis and h influenzae?

a. 7 days

b. 10-14 days

c. ≥ 21 days

a. 7 days

how long do you treat meningitis caused by s pneumoniae?

a. 7 days

b. 10-14 days

c. ≥ 21 days

b. 10-14 days

how long do you treat meningitis caused by listeria?

a. 7 days

b. 10-14 days

c. ≥ 21 days

c. ≥ 21 days

why do we sometimes give IV dexamethasone when a pt has meningitis?

can prevent neurologic complications

if we are giving IV dexamethasone for meningitis, when do we give it?

15-20 mins prior to or with first abx dose

what bacteria do we cover in meningitis empiric therapy?

• strep pneumo

• neisseria meningitidis

• listeria: neonates, age > 50, immunocompromised

• vanco: ≥ 1 month old

why can’t we use ceftriaxone in neonates?

biliary sludging and kernicterus (brain damage)

bacterial meningitis empiric regimen: neonates

ampicillin +

ceftazadime or cefepime ±

gentamicin

bacterial meningitis empiric regimen: 1 month to 50 years old

ceftriaxone or cefotaxime +

vanco

bacterial meningitis empiric regimen: > 50 years old or immunocompromised

ampicillin +

ceftriaxone +

vancomycin

if you see ampicillin for meningitis empiric tx what are we covering?

listeria

acute otitis media (AOM) s/sx

• bulging tympanic membrane

• otorrhea (middle ear effusion/fluid)

• otalgia (ear pain)

• tugging/rubbing ears

most AOM are caused by _____

a. viruses

b. bacteria

a. viruses

do they need abx for AOM: pt is < 6 months old

YES

do they need abx for AOM: pt is 6-23 months old with severe AOM

YES

do they need abx for AOM: pt is 6-23 months old with bilateral sx

YES

do they need abx for AOM: pt is 6-23 months old with unilateral sx

either: abx or observation 2-3 days

do they need abx for AOM: pt is ≥ 2 years old with severe AOM

YES

what is considered severe AOM?

• otalgia > 48 hours

• otorrhea

• temp ≥ 102.2º F

• ill appearance

abx preferred tx

amoxicillin 90 mg/kg/day

augmentin 90 mg/kg/day

high-dose

target amoxicillin to clavulanate ratio (AOM)

14:1

how to treat pts with AOM with a non-severe PCN allergy?

second/third gen cephalosporin

how long do we treat AOM: pt is < 2 years old

10 days

how long do we treat AOM: pt is 2-5 years old

7 days

how long do we treat AOM: pt is ≥ 6 years old

5-7 days

when do we use ceftriaxone IM daily for a pt with AOM?

tx failure (not improved after 2-3 days)

s/sx of common cold

• sneezing

• runny nose

• mild sore throat

• cough

s/sx of influenza

• sudden fever

• chills

• fatigue

• myalgia

s/sx of covid-19

• fever

• chills

• SOB

• myalgia

• loss of taste/smell

s/sx of pharyngitis (strep throat)

• sore throat

• fever

• swollen lymph nodes

• white patches (exudates) on tonsils

tx options for strep throat

penicillin VK

amoxicillin

acute sinusitis: bacterial causes

• s pneumoniae

• h influenzae

• m catarrhalis

s/sx of acute sinusitis

• nasal congestion

• purulent nasal discharge

• facial/ear/dental pain

• headache

when to tx acute sinusitis

• ≥ 10 days of persistent sx

• ≥ 3 days of severe sx (face pain, purulent nasal discharge, temp > 102ºF)

tx for bacterial acute sinusitis

augmentin

acute bronchitis s/sx

• non-productive or productive cough

  • 1-3 weeks

• chest wall tenderness

• wheezing

• rhonchi

how do you diagnose and tx acute bronchitis?

• rule out other causes

• chest X-ray: normal

• abx: not recommended

how do you distinguish pertussis from other causes of acute bronchitis?

series of forceful coughs followed by an inspiratory “whoop” sound

how do you treat pertussis (whooping cough)?

macrolides: azithromycin, clarithromycin

COPD exacerbation definition

incr. in sx that worsen over < 14 days

3 cardinal sx of COPD exacerbation

• incr. dyspnea

• incr. sputum volume

• incr. sputum purulence

when do COPD exacerbations recieve abx?

• all 3 cardinal sx present

• incr. sputum purulence + 1 other cardinal sx

• mechanically ventilated

abx for acute COPD exacerbation

• augmentin

• azithromycin

• doxy

• resp. FQ (levo or moxi)

common bacterial causes of CAP

• s pneumoniae

• h influenzae

• atypicals

  • mycoplasma pneumoniae

  • chlamydophila pneumoniae

common pneumonia sx

• SOB

• fever

• cough with purulent sputum

• rales

• tachypnea

gold standard for diagnosing CAP

chest X-ray: infiltrates, opacities, consolidations

duration of tx for CAP

5-7 days

outpatient CAP tx: no comorbidities

• amoxicillin

• doxy

• macrolide: azithromycin or clarithromycin

  • only if resistance ≤ 25%

outpatient CAP tx: comorbidities (chronic heart, lung, liver, or renal disease; DM; AUD; malignancy; asplenia)

• beta-lactam (augmentin or cephalosporin) + macrolide or doxy

• resp. FQ (moxi or levo)

inpatient non-severe CAP tx

• beta-lactam (ceftriaxone, ceftaroline, unasyn) + macrolide or doxy

• resp. FQ

inpatient severe CAP tx (ICU)

• beta-lactam + macrolide

• beta-lactam + FQ

CAP: MRSA: pt has prior respiratory isolation or positive nasal swab; what coverage do we add?

• vanco

• linezolid

CAP: pseudomonas: pt has prior respiratory isolation; what coverage do we use?

beta-lactam with pseudomonas coverage

• zosyn

• cefepime

• ceftazidime

• imipenem/cilastatin

• meropenem

when do we cover for MRSA in CAP?

• prior respiratory isolation

• positive nasal swab

• hospitalization and use of IV abx in past 90 days

when do we cover pseudomonas in CAP?

• prior respiratory isolation

• hospitalization and IV abx in past 90 days

what is the basic empiric regimen for HAP/VAP (not covering MRSA or double pseudomonas)?

cover pseudomonas and MSSA

• cefepime

• zosyn

• levofloxacin

risk factors for MRSA coverage in HAP/VAP

• IV abx use in past 90 days

• MRSA prevalence in unit is > 20% or unknown

• prior MRSA infection or + MRSA swab

• hospitalized ≥ 5 days prior to onset of VAP

when do you double cover pseudomonas in HAP/VAP?

• IV abx use in past 90 days

• prevalence of gram- resistance in unit > 10%

• hospitalized ≥ 5 days prior to onset of VAP

abx for pseudomonas

• zosyn

• cefepime

• ceftazidime

• imipenem/cilastatin

• meropenem

• levo or cipro

• aztreonam

• aminoglycosides

how is pulmonary TB transmitted?

aerosolized droplets

pulmonary TB s/sx

• cough

• hemoptysis

• purulent sputum

• fever

• night sweats

how do you diagnose latent TB?

TST/PPD teset

IGRA test

what can cause a false-positive TST/PPD test?

BCG vaccination

when would this latent TB test be positive: close contact of recent active TB; HIV; immunosuppressed

a. ≥ 5 mm

b. ≥ 10 mm

c. ≥ 15 mm

a. ≥ 5 mm

when would this latent TB test be positive: immigrants from high burden countries; clinical risk (IV drug use, diabetes); residents/employees of high-risk congregate settings (prisons, healthcare facilities, homeless shelters)

a. ≥ 5 mm

b. ≥ 10 mm

c. ≥ 15 mm

b. ≥ 10 mm

when would this latent TB test be positive: no risk factors

a. ≥ 5 mm

b. ≥ 10 mm

c. ≥ 15 mm

c. ≥ 15 mm

latent TB regimen options

• INH + rifapentine: weekly for 12 weeks

• INH + rifampin: daily for 3 months

• rifampin: daily for 4 months

• INH daily for 6-9 months

what is the biggest barrier to rifampin- and rifapentine-based latent TB regimens?

drug interactions

how do you diagnose active TB?

• chest x-ray: consolidation or cavitation

• AFB smear (non-specific)

• sputum culture or PCR

intensive phase of active TB tx

RIPE — 2 months

• Rifampin

• Isoniazid

• Pyrazinamide

• Ethambutol

continuation phase of active TB tx

RI — 4 months

• Rifampin

• Isoniazid

ADRs of rifampin

• orange-red discoloration of body secretions

  • can stain contact lenses and clothing

• incr. LFTs

• hemolytic anemia — positive Coombs test

• flu-like syndrome

what do we need to use with isoniazid to decr. peripheral neuropathy?

pyridoxine (vit. B6)

BBW with isoniazid

hepatitis

what do we need to monitor for sx of with isoniazid?

DILE

which TB drug can cause hyperuricemia/gout?

a. rifampin

b. isoniazid

c. pyrazinamide

d. ethambutol

c. pyrazinamide

which TB med can cause optic neuritis?

a. rifampin

b. isoniazid

c. pyrazinamide

d. ethambutol

d. ethambutol

rifampin can cause a decr. in concentration of what drugs?

• protease inhibitors

• warfarin

• oral contraceptives

what drugs can you absolutely not use rifampin with?

DOACs

most common causes of infective endocarditis?

• staph

• strep

• enterococci

how do you diagnose infective endocarditis?

• echo

• positive blood cultures

when do we add an abx (gentamicin) for synergy for infective endocarditis?

harder to treat

• prosthetic valve infections

• more resistant organisms

infective endocarditis: preferred abx regimen for viridans group streptococci

penicillin or ceftriaxone (± gentamicin)

infective endocarditis: preferred abx regimen for staph (MSSA)

nafcillin or cefazolin (+ gentamicin and rifampin if prosthetic valve)

infective endocarditis: preferred abx regimen for staph (MRSA)

vanco (+ gentamicin and rifampin if prosthetic valve)

infective endocarditis: preferred abx regimen for enterococci

• penicillin or ampicillin + gentamicin

• ampicillin + high-dose ceftriaxone

a patient is getting a root canal, what conditions would require amoxicillin 2 g prophylaxis?

• prosthetic heart valve

• heart valve repaired with artificial material

• hx of endocarditis

• heart transplant w/abnormal heart valve function

• certain congenital heart defects