Infectious Diseases II: Bacterial Infections Flashcards
What is the recommended perioperative antibiotic prophylaxis for
Cardiac/vascular or orthopedic surgical procedure
Common pathognes: MSSA & streptococci (skin flora)
Cefazolin
Beta-lactam allergy: clindamycin or vancomycin
Common pathognes: MSSA, streptococci
What is the recommended perioperative antibiotic prophylaxis for
Gastrointestinal surgical procedure
Common pathognes: skin flora, gram-negative and anaerobic organisms
Cefazolin + metronidazole
Alternatives: cefotetan, cefoxitin, or ampicillin/sulbactam
Common pathognes: skin flora, gram-negative and anaerobic organisms
What is the recommended antibiotic for
Meningitis
Common pathogens: S. pneumoniae, N. meningitidis, Listeria monocytogenes
Ceftriaxone or cefotaxime +/-
Ampicillin +/-
Vancomycin
- Use cefotaxime in neonates (ceftriaxone can caise biliary sludging and kernicterus in neonates)
- Ampicillin covers Listeria monocytogenes in neonates, age > 50 years and immunocompromised patients
- Vancomycin provides double coverage for S. pneumoniae in patients ≥ 1-month-old
What is the recommended antibiotic for
Acute otitis media
Common pathogens: S. pneumoniae, H. influenzae, Moraxella catarrhalis
Amoxiciilin
or
Amoxicillin/Clavulanate
90 mg amoxicillin/kg/day in 2 divided doses
What is the recommended antibiotic for
Pharyngitis
“strep throat”
Common pathogen: S. pyogenes
Penicillin or amoxicillin
What is the recommended antibiotic for
- Acute sinusitis
- Acute bacterial exacerbation of COPD
Common pathogens: S. pneumoniae, H. influenzae, Moraxella catarrhalis
Amoxicillin/Clavulanate
What is the recommended antibiotic for
Pertussis
“whooping cough”
Causative pathogen: Bordetella pertussis
Macrolides (azithromycin, clarithromycin)
What is the recommended antibiotic for
Outpatient CAP for “healthy” patients
Common pathogens: S. pneumoniae, H. influenzae, Mycoplasma pneumoniae
Healthy = no comorbidities
Comorbidities: chronic heart, lung, liver or renal disease, diabetes, alcohol use disorder, malignancy, or asplenia
Amoxicillin high-dose (1g TID)
or
Doxycycline
or
Macrolide (azithro, clarithro) if local pneumococcal resistant is < 25%
What is the recommended antibiotic for
Outpatient CAP for “high-risk” patients
Common pathogens: S. pneumoniae, H. influenzae, Mycoplasma pneumoniae
High risk = with comorbidities
Comorbidities: chronic heart, lung, liver or renal disease, diabetes, alcohol use disorder, malignancy, or asplenia
Beta-lactam plus macrolide or doxycycline
* Amoxicillin/clavulanate or cephalosporin (e.g., cefpodoxime, cefuroxime) plus
* Macrolide or doxycycline
or
Respiratory quinolone monotherapy (levofloxacin or moxifloxacin)
What is the recommended antibiotic for
Inpatient CAP for “non-severe” patients
Common pathogens: S. pneumoniae, H. influenzae, Mycoplasma pneumoniae
Non-severe = admission to a general medicine unit
Beta-lactam plus macrolide or doxycycline
* Preferred beta-lactams: ceftriaxone, cefotaxime, ceftaroline or ampicillin/sulbactam
or
Respiratory quinolone monotherapy (levofloxacin or moxifloxacin)
MRSA: add vancomycin or linezolid
Pseudomonas: use a beta-lactam with acitivity against Pseudomonas
Hospitalization and use of parenteral antibiotics in the past 90 days: use a regimen with antibiotics active against both MRSA and Pseudomonas
What is the recommended antibiotic for
Inpatient CAP for “severe” patients
Common pathogens: S. pneumoniae, H. influenzae
Severe = admission to the ICU
Beta-lactam + macrolide
or
Beta-lactam + respiratory quinolone monotherapy
Preferred beta-lactams: ceftriaxone, cefotaxime, ceftaroline or ampicillin/sulbactam
Do not use respiratory quinolone monotherapy
MRSA: add vancomycin or linezolid
Pseudomonas: use a beta-lactam with acitivity against Pseudomonas
Hospitalization and use of parenteral antibiotics in the past 90 days: use a regimen with antibiotics active against both MRSA and Pseudomonas
What is the recommended antibiotic for
HAP/VAP
Common pathogens: nosocomial pathogens
- All patients need an antibiotic for Pseudomonas and MSSA
- Add vancomycin or linezolid if risk for MRSA
- Use two antibiotics for Pseudomonas if risk for MDR gram-negative pathogens (do not use two beta-lactams together)
MDR gram-negative pathogens: Klebsiella spp., E. coli, Acinetobacter spp., Enterobacter spp.
Risk factors for MDR: IV antibiotic use in the past 90 days, prevelence of gram-negative resistance in hospital unit is > 10%, hospitalized ≥ 5 days prior to the onset of VAP
What is the recommended antibiotic for
Latent tuberculosis
Causative pathogen: Mycobacterium tuberculosis
- INH + rifapentine weekly for 12 weeks (do not use in pregnancy)
- INH + rifampin daily for 3 months
- Rifampin daily for 4 months
- Isoniazid daily for 6 or 9 months (preferred in HIV-positive patients)
What is the recommended antibiotic for
Active tuberculosis
Causative pathogen: Mycobacterium tuberculosis
Initial intensive phase (2 months) with RIPE:
Rifampin + Isoniazid + Pyrazinamide + Ethambutol
Continuation phase (≥ 4 months) with RI:
Rifampin + Isoniazid
All RIPE: ↑ LFTs, including total bilirubin
Rifampin: flu-like syndrome, orange bodily secretions, strong CYP3A4 inducer (can use rifabutin if unacceptable DDIs)
Isoniazid: peripheral neuropathy (give w/ pyridoxine/vitamin B6 25-50 mg daily), DILE
Rifampin and isoniazid: hemolytic anemia (identified w/ positive Coombs test)
Pyrazinamide: ↑ UA - do not use w/ acute gout
Ethambutol: visual damage (requires baseline and monthly vision exams), confusion/hallucinations
What are the common pathogens for
Infective endocarditis
Staphylococci, streptococci, enterococci
What is the recommended antibiotic for
Infective endocarditis
Beta-lactams
Beta-lactam allergy: vancomycin
Gentamicin is added to the antimicrobial regimen for synergy when the infection is more difficult to eradicate
Rifampin may be added in cases of staphylococcal prosthetic valve endocarditis
Who are at risk for
Infective endocarditis
Dental work needed, such as a root canal
+
Select cardiac conditions, including:
* Artifical (prosthetic) heart valve or heart valve rapaired with artifical material
* History of endocarditis
* Heart transplant with abnormal heart valve function
* Certain congenital heart defects including heart/heart valve disease
What is the recommended prophylaxis for
Infective Endocarditis
Amoxicillin 2 grams PO
Beta-lactam allergy: azithro or clarithro 500 mg, or doxycycline 100 mg
What is the recommended antibiotic for
Spontaneous Bacterial Peritonitis
Common pathogens: streptococci, proteus, E. coli, Klebsiella
Ceftriaxone x5-7 days
What are the secondary prophylaxis for
Spontaneous Bacterial Peritonitis
Common pathogens: streptococci, Proteus, E. coli, Klebsiella
Cipro or SMX/TMP
What are the common pathogens for
Skin and Soft-Tissue Infections (SSTIs)
Staphylococci and streptococci
What is the recommended antibiotic for
Impetigo
Common pathogens: S. pyogenes, S. aureus
Superficial infections
- Use warm, wet compresses to help remove dried crusts
- For limited, localized lesions: topical mupirocin
- For numerous, extensive lesions: cephalexin, dicloxacillin
What is the recommended antibiotic for
Folliculitis/Furuncle/Carbuncle
Common pathogens: S. aureus
Superficial infections
- Folliculitis and small furuncles may require only warm compresses to ↓ inflammation and help with drainage
- Incision & drainage (I&D) ± antibiotics is recommended for large furuncles and carbuncles
- Use antibiotics that cover MSSA and MRSA: SMX/TMP, doxycycline
What is the recommended antibiotic for
Cellulitis (non-purulent infections)
Common pathogens: Streptococci, S. aureus
Mild infections
Cephalexin
Beta-lactam allergy: clindamycin
What is the recommended antibiotic for
Abscess (purulent infections)
Common pathogens: S. aureus
Mild-moderate infections
Use oral antibiotics that cover MSSA and MRSA:
* SMX/TMP
* Doxycycline
What is the recommended antibiotic for
Severe purulent SSTI
Common pathogens: S. aureus (MRSA)
Mild-moderate infections
Use antibiotics with MRSA activity:
* Vancomycin
* Daptomycin
* Linezolid
What is the recommended antibiotic for
Necrotizing fasciitis
Common pathogens: S.pyogenes, S. aureus, gram-negatives, anaerobes
Mild-moderate infections
- Urgent surgical debridement
- Empiric therapy is broad: vancomycin or daptomycin + beta-lactam (piperacillin/tazobactam, meropenem) + clindamycin
Clindamycin to suppress streptococcal toxin production
What is the recommended antibiotic for
Acute uncomplicated cystitis
Common pathogens: E. coli, Proteus, Klebsiella, enterococci
- Nitrofurantoin (Macrobid) 100 mg PO BID x5 days
- SMX/TMP DS 1 tab PO BID x3 days
- Fosfomycin 3g x1 dose
Pregnancy: amoxicillin, cephalexin, fosfomycin (if beta-lactam allergy)
What is the recommended antibiotic for
Acute pyelonephritis
Common pathogens: E. coli, Proteus, Klebsiella
Moderately ill outpatient (PO)
* If local quinolone resistance ≤ 10%: cipro or levo (SMX/TMP or beta-lactam if concern for quinolone adverse effects)
* If local quinolone resistance > 10%: ceftriazone IV/IM, ertapenem IV/IM
Severely ill hospitalized patient (IV)
* Initial: ceftriaxone or a quinolone (cipro or levo)
* Concern for resistance: piperacillin/tazobactam or a carbapenem (if ESBL-producing organism suspected)
What is the recommended antibiotic for
Bacteriuria in pregnancy
- Beta-lactams are preferred (Augmentin or an oral cephalosporin)
Beta-lactam allergy: fosfomycin
What is the recommended antibiotic for
C. difficile
1st episode:
* FDX
* Vanco (standard regimen)
* Metronidazole (only if non-severe and other treatments are unavailable)
2nd episode:
* FDX
* Vanco (standard followed by prolonged tapered course)
3rd episode:
* FDX
* Vanco (standard followed by prolonged tapered course)
* Vanco + rifaximin
* Fecal microbiota transplantation
Adjunct bezlotoxumab can be considered for high-risk patients: ≥ 65 years, immunocompromised status, severe presentation and/or expeienceing a 2nd episode of CDI within the past 6 months
Fulminant/complicated disease (can occur with any episode/recurrence) is diagnosed when significant systemic toxic effects are present, such as hypotension, shock, ileus or toxic megacolon: Van PO/NG/PR + metronidazole
What is the recommended antibiotic for
Syphilis
Pathogen: treponema pallidum
Penicillin G benzathine (Bicillin L-A)
Beta-lactam allergy: doxycycline
Pregnancy: penicillin desensitization
What is the recommended antibiotic for
Neurosyphilis
Pathogen: treponema pallidum
Penicillin G aqueous
Beta-lactam allergy: penicillin desensitization
What is the recommended antibiotic for
Gonorrhea
Pathogen: neisseria gonorrhoeae
Ceftriazone
If chlamydia has not been excluded: add doxycycline
What is the recommended antibiotic for
Chlamydia
Pathogen: chlamydia trachomatis
- Non-pregnant: doxycycline
- Pregnant: azithromycin
What is the recommended antibiotic for
Bacterial vaginosis
Trichomoniasis
Bacterial vaginosis pathogen: gardnerella vaginalis
Trichomoniasis pathogen: trichomonas vaginalis
Metronidazole
What is the recommended antibiotic for
Genital warts
Pathogen: HPV
Imiquimod cream
What is the recommended antibiotic for
Common tickborne diseases:
* Rocky mountain spotted fever
* Lyme disease
* Ehrlichiosis
Rocky moyntain spotted fever pathogen: rickettsia rickettsii
Lyme disease pathogen: borrelia spp.
Ehrlichiosis pathogen: ehrlichia chaffeensis
Doxycycline
