Bacterial Infections Flashcards
How are perioperative ABX administered?
Pre-operative: infuse cefazolin/cefuroxime within 60 min before 1st incision; infuse quinolone/vanco 120 min before 1st incision
Perioperative: longer surgeries >4 hours or major blood loss
Post-operative: D/C ABX within 24 hours
Which ABX is preferred for cardiac/vascular surgeries and what is an alternative?
Cefazolin/cefuroxime
Alternative for beta-lactam allergy: Clindamycin or Vanco
Which ABX is preferred for orthopedic (joint replacement/hip fracture) surgeries and what is an alternative?
Cefazolin
Alternative for beta-lactam allergy: Clindamycin or Vanco
What ABX is preferred for GI surgeries (apendectomy, colorectal)?
Cefazolin + metronidazole, cefotetan, cefoxitin, or Unasyn
Alternative for beta-lactam allergy: clindamycin/metronidazole + aminoglycoside/quinolone
What are s/sx of meningitis?
- fever
- headache
- nuchal rigidity (stiff neck)
- altered mental status
What microbes are common causes of mengingitis?
- Neisseria meningitidis
- Streptococcus pneumoniae
- Haemophilus influenzae
- Listeria monocytogenes (neonates,
age>50, immunocompromised patients)
What is empiric treatment of meningitis in neonates <1 month?
Ampicillin (Listeria) +
Cefotaxime, ceftazidime, cefipime
+/- Gentamicin
* DO NOT use ceftriaxone in neonates causes biliary sludging (solids precipitate from bile) and kernicterus (brain damage from high bilirubin)
What is empiric treatment of meningitis in ages 1 month to 50 years?
Ceftriaxone + Vancomycin (double coverage of Strep)
What is the empiric treatment of meningitis in immunocompromised and aged>50?
Ampicillin (Listeria) + Ceftriaxone + Vancomycin (2x strep coverage)
What are s/sx of acute otitis media (AOM)?
- Buldging tympanic (eardrum) membranes
- Otorrhea (middle ear effusion/fluid)
- Otalgia (ear pain)
- Tuuging/rubbing of ears
- fever
- crying
What bacteria commonly cause acute otitis media?
- S. pneumoniae
- H. influenzae
- Moraxella catarrhalis
When should observation of AOM be considered?
Age <6 months: always treat with ABX
Age 6-23 months: symptoms in 1 ear only and non severe symptoms
Age ≥ 2y: non severe symptoms in 1 or both ears
Observe for 2-3 days if otalgia <48 hours, no otorrhea, temp <102.2
If symptoms do not improve or worsen, use ABX
What are first-line and alternative agents used to treat AOM?
- Amoxicillin 90mg/kg/day divided in 2 doses or Amoxicillin/Clavulanate 6.4 mg/kg/day in 2 divided doses
Preferred agent: Augmentin ES-600 (600mg amox/42.9mg clav) - mild-PCN allergy: Cefdinir 14mg/kg/day 1-2 divided doses OR other 2nd/3rd gen cephalosporin
What agents are used for treatment failure of AOM (not improved within 2-3 days)?
- if amoxicillin used use Augmentin
- Ceftriaxone 50mg/kg IM QD x 3 days
What are s/sx of the common cold (common respiratory viruses)?
- Sneezing
- Runny nose
- Mild sore throat
- Cough
- congestion
What are s/sx of influenza?
- Sudden onset fever
- Chills
- Fatigue
- Myalgia
- dry cough
- sore throat
- headache
What are s/sx of pharyngitis (repiraotry virus, S. gyogenes-GAS) ?
- Sore throat
- Fever
- Swollen lymph nodes
- White patches (exudates) on the tonsils
What testing should be done with symptoms of pharyngitis?
rapid antigen test for “strep throat”
What are 1st line treatments for S. pyogenes (strep throat)?
- Penicillin/Amoxicillin
- mild allergy: 1st/2nd gen cephalosporin
- severe allergy: macrolide/clindamycin
What are s/sx of acute sinusitis (S. pneimoniea, H. influenzae, M.catarrhalis)?
- Nasal congestion
- Purulent nasal discharge
- Facial/ear/dental pain/pressure
- Headache
- Ffver
When should someone get antibiotics with s/sx of acute sinusitis?
- ≥10 days of persistant sx
- ≥3 days of severe sx (face pain, purulent discharge, TEMP >102)
- worsening of sx after improvement
What are 1st line ABX for acute sinusitis (S. pneimoniea, H. influenzae, M.catarrhalis)?
Augmentin
What are s/sx of acute bronchitis?
non-productive/productive cough lasting 1-3 weeks; chest X-ray is normal
What ABX are used for acute bronchitis?
Not recommended not usually bacterial; supportive care
What s/sx of a COPD exacerbation require ABX?
Any 1 of the following:
1. increased dyspnea, sputum volume, and sputum purulence (must have all 3)
2. increased sputum purulence (yellow/green) + 1 other symptom
3. Mechanically ventilated
What ABX are preferred for COPD exacerbation (S. pneimoniea, H. influenzae, M.catarrhalis)?
- Amoxicillin/ clavulanate
- azithromycin
- doxy
- respiratory quinolone
What are preferred ABX for whooping cough (Bordatella pertussis)?
Macrolides (Azithromycin, clarithromycin)
What are s/sx of CAP?
- SOB
- Fever
- Cough with purulent sputum
- Rales (cracking in the lungs)
- Tachypnea (increased respiratory rate)
- pleuritic chest pain
- decreased breath sounds
How is CAP diagnosed?
Gold standard: chest x-ray with “infiltrates”, “opacities”, “consolidations”
What are most likely bacterial causes of CAP?
- S. pneumoniae
- H. influenzae
- M.catarrhalis
- C. pneumoniae
What is the usual treatment duration for CAP?
5-7 days
What is the preferred treatment of outpatient CAP in healthy patients (no comorbidities)?
- Amoxicillin (1g TID)
- Doxy
- macrolide if resistance <25%
What is the preferred treatment of outpatient CAP in high risk patients (chronic heart disease, lung/liver/renal disease, DM, alcohol use disorder, malignancy, asplenia)?
- beta-lactam (augmentin/cephalosporin preferred) + macrolide/doxy
- respiratory quinolone
What is preferred treatment for
non severe inpatient CAP?
- Ceftriaxone, Unasyn, or other beta-lactam + macrolide/ doxycycline
- Add vanco if MRSA coverage is needed
- If pseudomonas coverage needed use Zosyn, cefepime, meropenem
What is the preferred treatment for in patient CAP treatment in ICU patients?
- beta-lactam+ macrolide
- beta-lactam+ respiratory quinolone (do not use quinolone monotherapy)
- Add vanco if MRSA coverage is needed
- If pseudomonas coverage needed use Zosyn, cefepime, meropenem
When would coverage for both MRSA and pseudomonas be necessary?
hospitalization and use of parenteral ABX within the past 90 days
What is HAP?
onset >48 hours after hospital admission
What is VAP?
onset >48 hours after the start of mechanical ventilation
What are risk factors for MRSA?
- IV ABX use within the past 90 days
- MRSA prevalence >20% in the hospital unit or unknown
- prior MRSA infection
- positive MRSA nasal swab
What are risk factors for MDR grm neg pathogens?
- IV ABX use in the past 90 days
- prevalence of gram neg resistance in hospital unit >10 %
- hospitalized ≥ 5 days prior to the onset of VAP
What are preferred regimens for HAP/VAP?
- ALL need MSSA and pseudomonas:
Cefepime/Zosyn/Levofloxacin - If at risk for MRSA:
vanco/linezolid - If at risk for MDR gram neg:
add a 2nd antipseudomonal (aztreonam, aminoglycoside, levo/cipro)
What bacteria causes TB?
Mycobacterium tuberculosis; anaerobic, non-spore forming bacillus
How is TB transmitted?
highly contagious aerosolized droplets during active pulmonary TB
What is latent TB?
Symptoms are not present and contained by the immune system; not contagious but can advance to active
What are s/sx of TB?
- Cough/ hemoptysis (coughing up blood)
- Fever
- Night sweats
- purulent sputum
- unintentional weight loss
What precautions are taken with active TB?
- patient isolation in a single-negative pressure room
- healthcare workers must wear a respirator mask
How is latent TB diagnosed?
- tuberculin skin test (TST/PPD) injected intradermally and inspected for induration (raised area) 48-72 hours later
- interferon-gamma release assay IGRA
- chest x-ray
What indurations are the criteria for positive TST?
≥5mm: HIV, Immunosuppression, close contact with recent active TB
≥10mm: high risk congregate settings (prisons, healthcare facilities, homeless shelters), clinical risk (IV drug use, DM)
≥15mm: no risk factors
What will cause a false positive TST test?
hx of bacille Calmette-Guerin, BCG vaccination (used in countries with high TB rates)
What is the preferred duration of latent TB treatment?
shorter regimens (3-4 months preferred)
What are preferred regimens for latent TB?
- Isoniazid (INH) + rifapentine weekly x 12 weeks via DOT (directly observed therapy)
- INH + rifampin daily X 3 months
- Rifampin 600mg QD x 4 months
- INH 300mg QD X 6-9 months (Preferred in HIV-positive patients x 9 months)
How is active TB diagnosed?
- Acid-fast bacilli AFB smear and culture of sputum sample (may take up to 6 weeks, slow growing)
- chest x ray showing consolidation or cavitation
How is active TB treated?
- intensive phase: RIPE x 8 weeks (until cultures and sensitivities available)
- continuation phase: 2 drugs x 4 months (usually INH + rifampin) but base on culture/sensibilities
What are CIs with Rifampin?
DO NOT use with protease inhibitors
What are SEs with Rifampin?
- Orange-red coloring of body secretions (Saliva, Sweat, Urine, Tears); can stain Contact lenses, Clothing, and bedsheets
- elevated LFTs
- Hemolytic anemia (+ Coombs test)
- flu-like syndrome
- GI upset
- rash/pruritis
Which drug can replace rifampin if needed due to DIs?
Rifabutin