23. Infectious Disease II Flashcards
Pre-operative abx administration timing
Infuse abx (e.g. cefazolin or cefuroxime) within 60 min before first incision
If quinolone or vancomycin, start infusion 120 min before first incision
In what situations would additional doses of abx be administered during a surgery (intra-operative)?
Longer surgeries (>4hr)
Major blood loss
T/F: Abx are often continued up to 48 hours after surgery
False - abx are usually not needed post-operatively; if used, discontinue after 24 hours
Perioperative abx selection: ____ is preferred for most surgeries to prevent MSSA and streptococcal infections. ___ is an alternative if the patient has a beta-lactam allergy
Cefazolin (or cefuroxime) is preferred
Clindamycin is an alternative
Perioperative abx selection: In GI surgeries, ppx abx regimen needs to cover skin flora plus ___ and ___
Broad GN and anaerobic
Perioperative abx selection: ____ should be included if MRSA colonization or risk is present. This is also an alternative (instead of clindamycin) if the patient has a beta-lactam allergy.
Vancomycin
Perioperative abx selection: Which abx would you recommend for cardiac or vascular procedures? What if they have beta-lactam allergy?
Cefazolin or cefuroxime
Beta-lactam allergy: clindamycin or vancomycin
Perioperative abx selection: Which abx would you recommend for orthopedic (e.g. joint replacement, hip fracture repair) surgery? What if they have beta-lactam allergy?
Cefazolin
Beta-lactam allergy: clindamycin or vancomycin
Perioperative abx selection: What abx would you recommend for GI (e.g. appendectomy, colorectal surgery) surgery? What if they have beta-lactam allergy?
Cefazolin + metronidazole, cefotetan, cefoxitin, or amp/sulb
Beta-lactam allergy: clindamycin or metronidazole + aminoglycoside or quinolone
S/sx of meningitis
Fever, HA, nuchal rigidity (stiff neck), altered mental status
Others:L chills, vomiting, seizures, rash, and photophobia
How is meningitis diagnosed?
Lumbar puncture (LP), sample of CSF is collected and analyzed
Higher CSF pressure during LP procedure is a sign of possible infection
T/F: Meningitis is mostly caused by bacterial infections but can be d/t viral or fungi
False - mostly caused by VIRAL but can be d/t bacterial or fungi
Which bacteria most commonly cause meningitis?
Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae
The risk of meningitis d/t ___ is higher in which patient populations?
Listeria monocytogenes
Neonates
Pts age>50
Immunocompromised pts
____, administered 15-20 min prior to or with the first abx dose can prevent neurological complications (e.g. hearing loss) and death from pneumococcal meningitis.
Dexamethasone
Adult dosing: 0.15mg/kg (rounded to nearest 10 mg) IV q6hr for 4 days
If S. pneumoniae is not the cause of meningitis, dexamethasone can be d/c
Meningitis: Empiric Treatment: Coverage
Streptococcus pneumoniae and Neisseria meningitidis for most adults
Add Listeria monocytogenes coverage in neonates, age >50yo, and immunocompromised pts
Add vancomycin in pts ≥12 month old for double coverage of Streptococcus pneumoniae
Meningitis: Empiric Treatment: Age <1 month (neonate): Treatment Regimen
Ampicillin (Listeria coverage) + (Cefotaxime or Gentamicin)
Note: CANNOT use ceftriaxone - biliary sludging and kernicterus in neonates
Meningitis: Empiric Treatment: Treatment Regimen: 1 month to 50 yo
(Ceftriaxone or cefotaxime) + Vancomycin
Meningitis: Empiric Treatment: Treatment Regimen: Age >50 or immunocompromised
Ampicillin (for Listeria coverage) + (Ceftriaxone or cefotaxime) + Vancomycin
____ can cause biliary sludging and kernicterus in neonates. Do NOT use in neonates.
Ceftriaxone
Meningitis: Empiric Treatment: Treatment Regimen: Beta-lactam allergy
Quinolone (e.g. moxifloxacin) + vancomycin ± SMX/TMP (for Listeria coverage); obtain ID consult
S/sx of acute otitis media (AOM)
Bulging tympanic (eardrum) membranes, otorrhea (middle ear effusion/fluid), otalgia (ear pain), fever, crying and tugging/rubbing ears
T/F: Most AOM is viral and abx will be ineffective
True
AOM bacterial infection is typically caused by ____
S. pneumoniae, H. influenzae, Moraxella catarrhalis
When is observation for 2-3 days recommended for AOM?
If symptoms are non-severe: otalgia <48 hrs, no otorrhea, temp <102.2ºF (39ºC) and:
Age 6-23 months: only in 1 ear
Age ≥2 years: in one or both ears
If no improvement or worsens, use abx
Observation is not an option for children age ____ and abx should be prescribed
<6 months
AOM: First-line treatment
High-dose amoxicillin 90mg/kg/day, divided into 2 doses OR
Amox/clav 90mg/kg/day, divided into 2 doses (preferred if pts received amoxicillin in the past 30 days)
AOM: Non-severe penicillin allergy
2nd or 3rd gen cephalosporin
Cefidinr, cefuroxime, cefpodoxime, or ceftriaxone
AOM: If treatment fails (not improved after 2-3 days)
Amox/clav 90mg/kg/day, divided in 2 doses (if initial treatment was amoxicillin) OR
ceftriaxone 50 mg/kg IM daily for 3 days
Patient complains of sneezing, runny nose, mild sore throat, cough, and congestion. Should they get abx?
No. This patient most likely has common cold (caused by respiratory viruses like rhinovirus, seasonal coronavirus) and generally resolves in a few days.
Recommend symptomatic care
Patient complains of sudden onset of fever, chills, fatigue, myalgia, dry cough, sore throat, and HA. Should they get abx?
This patient most likely has influenza virus.
Anti-infective care is recommended if suspected or confirmed infection AND (symptoms <48 hrs, severe illness (e.g. hospitalized), OR symptoms plus risk factors for influenza complications)
Recommend symptomatic care with or without antiviral
Patient complains of sore throat, fever, swollen lymph nodes, white patches (exudates) on the tonsils but no cough, runny nose, or congestion. What is their diagnosis?
Pharyngitis (“strep throat”) typically caused by respiratory viruses, Group A Streptococcus (S. pyogenes)
Take rapid antigen test before giving abx
Patient has a positive rapid antigen test for strep throat. What abx do you recommend?
Penicillin or amoxicillin
Mild PCN allergy: 1st or 2nd gen cephalosporin
Severe reaction to PCN: macrolide (clarithromycin, azithromycin) or clindamycin
Patient complains of nasal congestion, purulent nasal discharge, facial/ear/dental pain, HA, and fever. What is their diagnosis?
Acute sinusitis typically caused by respiratory viruses, S. pneumoniae, H. influenzae, M. catarrhalis
Patient is diagnosed with acute sinusitis. When should abx be considered?
≥10 days of persistent symptoms OR
≥ 3 days of severe symptoms (face pain, purulent nasal discharge, temp > 102ºF) OR
Worsening symptoms after initial improvement
Patient is diagnosed with acute sinusitis and symptoms have not improved for 11 days. When abx do you recommend?
Amox/clav OR
symptomatic care for up to 7 days, abx can be used when symptoms worsen or do not improve
What are some key defining features of acute bronchitis?
Cough lasting 1-3 weeks, chest wall tenderness, wheezing and/or rhonchi
Usually preceded by an upper respiratory tract virus, such as rhinovirus, coronavirus, or influenza virus
Chest X-ray findings are typically normal (rules out other causes of acute cough like pneumonia, COPD exacerbation) and cultures are not routinely performed
Acute bronchitis is typically caused by viral infections. While rare, what are some bacterial causes?
S. pneumoniae, H. influenzae, or atypical pathogens (e.g. Mycoplasma pneumoniae)
Patient is diagnosed with acute bronchitis. What is your abx recommendation?
Abx not recommended. Symptoms are generally self-limiting and can be managed with supportive care
Pertussis or “whooping cough” acute bronchitis caused by _____, characterized by forceful coughs followed by an inspiratory “whoop” sound
Bordatella pertussis
How do you confirm dx of pertussis?
Nasopharyngeal swab culture or PCR test for B. pertussis
Pertussis is highly contagious and should be treated with ___
macrolides (azithromycin, clarithromycin)
What are the 3 cardinal symptoms of COPD exacerbation?
Increaed dyspnea
Increased sputum volume
Increased sputum purulence
What causes COPD exacerbations?
Viral infections
Bacterial infections (e.g. H. influenzae, M. catarrhalis, S. pneumoniae)
Environmental pollution or an unknown cause
Supportive treatment (e.g. oxygen, systemic steroids, inhaled bronchodilators) are often adequate but abx is recommended if which criteria are met?
All 3 cardinal symptoms (increased dyspnea, sputum volume, sputum purulence) OR
Increased sputum purulence + 1 additional symptom OR
Mechanically ventilated
If abx is used for COPD exacerbation, what are the preferred abx?
Amox/clav
Others: azithromycin, doxycycline, respiratory FQ
S/sx of community-acquired pneumonia (CAP)
SOB, fever, cough with purulent sputum, pleuritic chest pain, rales (crackling lung sounds), tachypnea (increased respiratory rate), and decreased breath sounds
Gold standard dx test chest x-ray with “infiltrates”, “opacities” or “consolidations”
Which bacteria can cause CAP?
S. pneumoniae, H. influenzae, M. pnuemoniae, and possibly C. pneumoniae
____ is not used for CAP because it is not a respiratory FQ since it does not reliably cover S. pneumoniae
Ciprofloxacin
Typical duration of treatment for CAP is ___
5-7 days
Recommended outpatient empiric regimen for CAP patients who are healthy (no comorbidities)
Amox high dose (1g TID) OR
doxycycline OR
macrolide (azithromycin or clarithromycin) if local pneumococcal resistance is <25%
Recommended outpatient empiric regimen for CAP patients who are high risk with comorbidities
Beta-lactam + macrolide or doxycline:
- amox/clav or cephalosporin (e.g. cefpodoxime, cefuroxime)
OR
Respiratory FQ monotherapy: Moxifloxacin or levofloxacin
Recommended inpatient empiric regimen for nonsevere CAP
Beta-lactam + macrolide or doxycycline
- Preferred beta-lactam: ceftriaxone, cefotaxime, ceftaroline, or amp/sulb
OR
Respiratory FQ monotherapy: moxifloxacin or levofloxacin
Recommended inpatient empiric regimen for severe CAP (in ICU)
Beta-lactam + macrolide
OR
Beta-lactam + respiratory FQ (do NOT use quinolone monotherapy)
Recommended inpatient abx for MRSA coverage (prior respiratory isolation or positive nasal swab)
Vancomycin or linezolid
Recommended inpatient abx for Pseudomonas coverage (prior respiratory isolation)
Pip/tazo, cefepime, fetazidime, imipenem/cilastin, or meropenem
Recommended inpatient abx for previous hospitalization and use of parenteral abx in the past 90 days
Use regimen that covers both MRSA and Pseudomonas
What is the difference between hospital-acquired pneumonia (HAP) vs ventilator-associated pneumonia (VAP)?
HAP = onset > 48 hours after hospital admission
VAP = onset > 48 hours after start of mechanical ventilation - can be reduced by proper hand-washing, elevating head of the bed ≥30 degrees, weaning off ventilator asap, removing NG tubes when possible, and d/c unnecessary stress ulcer ppx (e.g. PPI)
What are common pathogens in HAP and VAP?
Nosocomial pathogens
Increased risk for MRSA, MDR GN rods including P. aeruginosa, Acinetobacter spp. Enterobater spp., E. coli, and Klebsiella spp.
HAP and VAP empiric regimen base
Pseudomonas and MSSA coverage - examples: cefepime, pip/tazo, levofloxacin
HAP and VAP add on regimen if risk for MRSA (IV abx use in past 90 days, MRSA prevalence in hospital unit is >20% or unknown, prior MRSA infection or positive MRSA nasal swab)
Vancomycin or linezolid
Example regimens:
cefepime + vancomycin
Meropenem + linezolid
Aztreonam + vancomycin
HAP and VAP regimen if risk for MDR GN pathogens (IV abx use in past 90 days, prevalence of GN resistance in hospital unit is >10% or unknown, ≥ 5 days prior to the onset of VAP)
Use 2 abx for Pseudomonas
Examples:
Pip/tazo + ciprofloxacin + vancomycin
Cefepime + gentamicin + linezolid
Abx for pseudomonas list used in HAP or VAP
Do NOT use 2 beta-lactams together
Beta-lactams: pip/tazo, cefepime, ceftazidime, imipenem/cilastatin, meropenem
Levofloxacin or ciprofloxacin
Aztreonam
Aminoglycosides (typically tobramycin) - always used in combo with other antipseudomonal drug
Tuberculosis (TB) is caused by _____ (an aerobic, non-spore forming bacillus)
Mycobacterium tuberculosis
With latent disease, the immune system is able to contain the infection and the patient lacks symptoms. Active pulmonary TB is transmitted by _____ and is highly contagious.
aerosolized droplets (e.g. sneezing, coughing, talking)
S/sx of TB
cough/hemoptysis (coughing up blood), purulent sputum, fever, night sweats, and unintentional weight loss
Your patient has active pulmonary TB. What is required of the patient and the healthcare workers?
Patient needs to be in isolation in a single negative-pressure room
Healthcare workers need to wear respiratory mask (N95)
How is latent TB diagnosed?
Tuberculin skin test (TST), also called purified protein derivative (PPD) test, or an interferon-gamma release assay (IGRA) blood test
In which patients can a false-positive TB test occur?
Those who received BCG vaccine
Dx of latent TB: Criteria for positive TST results: ≥5 mm induration
Close contacts of recent active TB cases
HIV infection
Immunosuppression (e.g. transplant, chemotherapy)
Dx of latent TB: Criteria for positive TST results: ≥10 mm induration
Immigrants from high burden countries
clinical risk (e.g. IV drug uses, DM)
Residents/employees of “high-risk” congregate settings (e.g. prisons, healthcare facilities, homeless shelters)
Dx of latent TB: Criteria for positive TST result1s: ≥5 mm induration
Patients with no risk factors
Latent TB treatment options
Isoniazid and rifapentine once weekly x 12 weeks via directly observed therapy (DOT) or self-administered. do NOT use this regimen for pregnant patients
Isoniazid with rifampin daily for 3 months
Rifampin 600mg daily for 4 months
Isoniazid 300mg daily for 6 or 9 months - may be preferred in HIV positive patients taking antiretroviral therapy (lower risk of DDIs); if used, take for 9 months
M. tuberculosis (MTB) is an ___ (AFB). AFB smear can detect but it is not specific to MTB. Definitive dx must be made with PCR or sputum culture results. Final culture and susceptibility results can take up to ___
Acid-fast bacilli
6 weeks (slow-growing organism)
Active TB treatment is divided into 2 phases: ___ and ____
intensive and continuation
TB intensive phase regimen consists of 4 drugs for 2 months. What are they?
Rifampin, isoniazid, pyrazinamide, and ethambutol daily or x5/week
(RIPE therapy)
Note: 4 drugs for 2 months
TB continuation phase (typically ____ months) treatment can be scaled back to 2 drugs (commonly ___ and ___) based on drug susceptibility of the isolate
4 months (may be extended to 7 months in select cases (e.g. sputum culture remains positive after 2 months of treatment, or if intensive phase treatment did not include pyrazinamide)
rifampin and isoniazid daily, 5x/week or 3x/week
Note: 2 drugs for 4 months
T/F: Latent TB is when a patient shows no symptoms but is still contagious
False - patient shows no symptoms and is not contagious, treated with 1 or 2 drugs for 3-4 months (preferably)
Contraindications for rifampin (Rifadin)
Do not use with protease inhibitors
Side effects for rifampin (Rifadin)
Increased LFTs, hemolytic anemia (detected with positive Coombs test), flu-like syndrome, GI upset, rash/pruritus
Orange-red discoloration of body secretions (saliva, urine, sweat, tears); can stain contact lenses, clothing, and bedsheets
Rifampin has many DDIs; ___ has fewer DDIs and can replace rifampin in some cases (e.g. HIV patients taking protease inhibitors), thought a DDI screen is still needed
Rifabutin
You should also take ____ when taking isoniazid to decrease risk of ____
pyridoxine (vit B6) 25-50mg PO daily
decrease risk of isoniazid associated peripheral neuropathy
Boxed warning for isoniazid
severe and fatal hepatitis
Contraindications for isoniazid
Active liver disease, previous serious adverse reaction to isoniazid
Warnings for isoniazid
Peripheral neuropathy (higher risk in pts predisposed to neuropathy (e.g. DM, HIV, renal failure, alcohol use disorder, elderly, malnourished)
Pyridoxine (vit B6) supplementation recommended for these patients and patients who are pregnant or breastfeeding
Side effects for isoniazid
Increased LFTs (usually asymptomatic)
Drug induced lupus erythematosus (DILE), hemolytic anemia (detected with positive Coombs test), agranulocytosis, aplastic anemia, hyperglycemia, headache, GI upset, pancreatitis, SJS/DRESS, optic neuritis
Contraindications for pyrazinamide
Acute gout, severe hepatic damage
Side effects for pyrazinamide
Increased LFTs, hyperuricemia/gout, GI upset, malaise, arthralgia, myalgia, rash
Contraindications for ethambutol (Myambutol)
Optic neuritis (risk vs benefit decision)
Do NOT use in young children, unconscious patient or any patient who cannot discern and report visual changes
Side effects for ethambutol (Myambutol)
Increased LFTs, optic neuritis (dose-related), confusion, hallucinations
decreased visual acuity, partial loss of vision/blind spot and/or color blindness (usually reversible), rash, HA, N/V
Rifampin is a potent (inducer/inhibitor) of CYP___ and p-gp (others: 1A2, 2C8, 2C9, 2C19)
Potent inducer
CYP 3A4 and Pgp
Can decrease conc and therapeutic effect of many other drugs
Rifampin can decrease serum conc of which drugs?
Protease inhibitors (substitute rifabutin)
Warfarin (very large drop in INR is common, requires increased dose of warfarin)
Oral contraceptives (decreased efficacy; requires additional backup contraceptive methods)
It is recommended to NOT use rifampin with certain anticoagulants. What are they?
Apixaban, rivaroxaban, edoxaban, or dabigatran
RIPE Therapy for TB: Monitoring Infection
Sputum sample (for culture), symptoms, and chest x-ray (are lungs clear or clearing up?)
RIPE Therapy for TB: Drug Specific Key Points: All RIPE drugs
Increased LFTs, including total bilirubin - monitor
RIPE Therapy for TB: Drug Specific Key Points: Rifampin
Orange bodily secretions
strong CYP450 inducer (can use rifabutin if unacceptable DDIs
Flu-like symptoms
RIPE Therapy for TB: Drug Specific Key Points: Isoniazid
Peripheral neuropathy: give with pyridoxine (vitamin B6) 25-50 mg PO daily
Monitor for symptoms of DILE
RIPE Therapy for TB: Drug Specific Key Points: Rifampin and Isoniazid
Risk for hemolytic anemia (identified with positive Coombs test)
RIPE Therapy for TB: Drug Specific Key Points: Prazinamide
Increased uric acid - do not use with acute gout
RIPE Therapy for TB: Drug Specific Key Points: Ethambutol
Visual damage (requires baseline and monthly vision exams)
Confusion/hallucinations
Infective endocarditis is dx using the Modified Duke Criteria, which includes ___ and ___
echocardiogram and positive blood cultures
3 Most common species of organisms that cause infective endocarditis are ___,___, and ____
staphylococci
Streptococci
Enterococci
Infective endocarditis empiric treatment often includes __ and __
vancoymycin
ceftriaxone
____ is added to the infective endocarditis antimicrobial regimen for synergy when the infection is more difficult to eradicate, such as with prosthetic valve infections or when treating more resistant organisms
Gentamicin
What is the typical duration for infective endocarditis treatment?
4-6 weeks of IV abx treatment (may be longer if prosthetic valves and/or more resistant organisms involved)
Duration of gentamicin synergy (if used for infective endocarditis treatment) is ___, depending on the organism being treated when the presence or absence of a prosthetic valve
2-6 weeks
What is target peak and trough levels of gentamicin when used for synergy in infective endocarditis treatment?
Peak 3-4 mcg/mL
Trough <1 mcg/mL
Infective Endocarditis Treatment: Preferred abx regimen: Viridans group streptococci present
PCN or CTX (± gentamicin)
If beta-lactam allergy: vancomycin monotherapy
Infective Endocarditis Treatment: Preferred abx regimen: MSSA present
Nafcillin or cefazolin (+ gentamicin and rifampin if prosthetic valve)
If beta-lactam allergy: vancomycin (+ gentamicin and rifampin if prosthetic valve)
Note: daptomycin monotherapy is alt for MSSA IE when pt has beta-lactam allergy and no prosthetic valve
Infective Endocarditis Treatment: Preferred abx regimen: MRSA present
Vancomycin (+gentamicin and rifampin if prosthetic valve)
Infective Endocarditis Treatment: Preferred abx regimen: Enterococci
For both native and prosthetic valve IE: PCN or ampicillin + gentamicin or ampicillin + high-dose CTX
If beta-lactam allergy: vancomycin + gentamicin
If VRE: daptomycin or linezolid
Which patients are at high risk for infective endocarditis and require dental ppx?
Dental work needed, such as root canal +
Select cardiac conditions, including:
- Prosthetic heart valve or heart valve repaired with artificial material
Hx of endocarditis
Heart transplant with abnormal heart valve function
Certain congenial heart defects including heart/heart valve disease
Adult regimen for IE dental ppx: First line
Amoxicillin 2 grams PO single dose 30-60 min before dental procedure
Adult regimen for IE dental ppx: NPO
Ampicillin 2g IM/IV OR Cefazolin or CTX 1g IM/IV
Adult regimen for IE dental ppx: PCN allergy
Azithromycin or clarithromycin 500mg OR doxycycline 100mg
Spontaneous bacterial peritonitis (SBP) is suspected if an ascitic fluid sample reveals ____
≥250 cells/mm3 PMNs (polymorphonuclear leukocytes)
Empiric treatment for SBP first line
CTX for 5-7 days
Alternative treatment for SBP if critically ill or at risk for MDR pathogens
Carbapenems (e.g. meropenem)
Secondary PPX for SBP
SMX/TMP or a quinolone (e.g. ciprofloxacin)
What are common intra-abdominal infections?
Appendicitis, cholecystitis (acute inflammation of gallbladder d/t obstruct stone), cholangitis (infection of common bile duct), secondary peritonitis (caused by ulceration, ischemia, obstruction, surgery), diverticulitis
Intra-abdominal infections are usually polymicrobial so empiric abx treatment should target multiple pathogens including ___, ___, and ___
streptococci, enteric GN, and anerobes (e.g. B. fragilis)
What increases risk of MDR pathogens?
Critically ill
Hospitalized > 48 hrs
abx in past 90 days
If there is a risk of MDR pathogens, coverage of __ and other resistant organisms may be necessary for intra-abdominal infections
pseudomonas
Treatment options for intra-abdominal infections: Community-acquired (low risk)
Ertapenem
Moxifloxacin
(Cefuroxime, cefotaxime, or CTX) + metronidazole
(Ciprofloxacin or levofloxacin) + metronidazole
Covers: PEK, anaerobes, streptococci
Treatment options for intra-abdominal infections: Risk for resistant or nosocomial pathogens
Carbapenem (except ertapenem)
Pip/tazo
(cefepime or ceftazidime) + metronidazole
Covers: PEK, Pseudomonas, Enterobacter, anaerobes, streptococci ± enterococci
What are examples of superficial SSTIs
Impetigo, furuncle, carbuncle
What is an example of infection that penetrate the subcutaneous tissues
Cellulitis
SSTI classifications: Mild infection
Systemic signs abset
SSTI classifications: Moderate infection
Systemic signs present (Temp >100.4ºF, HR >90, WBC > 12,000 or <4000 cell/mm3
SSTI classifications: Sevefre infection
Systemic signs present
Signs of deeper infection (e.g. fluid-filled blisters, skin sloughing, hypotension, or evidence of organ dysfunction)
Patient is immunocompromised or failed oral abx + incision and drainage (for purulent infections)
Patient comes in with a blister-like rash around their mouth that looks like honey-colored crust. What do they have and what do you recommend?
Impetigo
Use warm, wet compresses to help remove dried crusts
Limited localized lesions: Apply topical abx, typically mupirocin (alt: retapamulin (Altabax) and ozenoxacin (Xepi)
Numerous, extensive lesions: Cephalexin or dicloxacillin
Define folliculitis
A superficial infection of hair follicles (looks like red pimples)
Define furuncle (boil)
Purulent infection of hair follicle
Define carbuncle
Group of infected furuncles
What is the bacterial cause of folliculitis/furuncle/carbuncles
S. aureus, including community-acquired MRSA (CA-MRSA)
Folliculitis and small furuncles may require only warm compresses to decrease inflammation and help with drainage. For larger furuncles and carbuncles, I&D ± abx may be required. What abx would you recommend?
SMX/TMP or Doxycycline
Covers: MSSA and MRSA
What are s/sx of cellulitis
Mild symptoms: localized pain, swelling, redness, warmth
Often occurs on the legs, generally unilateral, can rapidly spread/expand
What abx do you recommend for cellulitis infections?
Cephalexin
Others: dicloxacillin
Beta-lactam allergy: clindamycin
Duration: 5 days (longer if no improvement after 5 days)
What is the bacterial cause of an abscess?
S. aureus, including CA-MRSA
What abx do you recommend for abscess
SMX/TMP or doxycycline
Others: minocycline, clindamycin, linezolid (but more expensive)
Covers MSSA and MRSA
If cultures show MSSA, use cephalexin
What abx do you recommend for severe purulent SSTI
MRSA coverage:
Vancomycin (goal trough 10-15)
Daptomycin
Linezolid
Others: ceftaroline, tedizolid, telavancin
Once clinically stable, can switch to PO abx
What is necrotizing fascilitis
A life-threatening, fast-moving type of skin infection that rapidly destroys tissue and can quickly penetrate down to the muscle
Presentation: intense pain/tenderness over affected skin and udnerlying muscle (often out of proportion with clinical findings), skin discoloration, edema, systemic signs
Requires emergency treatment in a hospital
What abx do you recommend for necrotizing fascilitis
Urgent surgical debridement
Broad empiric therapy:
Vancomycin or daptomycin + beta-lactam (pip/tazo, meropenem) + clindamycin (to suppress streptococcal toxin production
Treatment of Mod-severe diabetic foot infections: No MRSA coverage needed
Amp/sulb
Pip/tazo
Carbapenem (meropenem, ertapenem)
Moxifloxacin
(CTX, cefepime, levofloxacin, ciprofloxacin) + metronidazole
Pseudomonas coverage: pip/tazo, meropenem, cefepime, levofloxacin, ciprofloxacin
Treatment of Mod-severe diabetic foot infections: MRSA Coverage needed
Add vancomycin, daptomycin, or linezolid to empiric regimen
What is the typical duration for moderate-severe diabetic foot infection treatment?
7-14 days
What is the typical duration for more severe, deep tissue infection diabetic foot infection treatment?
2-4 weeks
What is the typical duration for severe, limb-threatening or bone/joint infection diabetic foot infection treatment?
4-6 weeks
What is the typical duration for osteomyelitis diabetic foot infection treatment?
Longer courses, may require chronic suppressive therapy
S/sx of cystitis
Urgency and frequency, nocturia
Dysuria (painful urination, burning)
Suprapubic tenderness
Hematuria
Urinalysis: Pyuria (WBC >10 cells/mm3), bacteria, and positive leukocyte esterase and/or nitrates
S/sx of pyelonephritis
Flank pain
Abd pain, N/V
Fever, chills, and malaise
Most acute cystitis is caused by ___
E. coli
Drugs of choice for acute uncomplicated cystitis
Nitrofuantoin (Macrobid) 100mg PO BID x 5 days (contraindicated if CrCl <60)
OR SMX/TMP DS 1 tab po BID x3 days (do NOT use if sulfa allergy or ≥ 20% e.coli resistance rate)
OR fosfomycin 3g x1 dose
Alt options for acute uncomplicated cystitis
Beta-lactam (amox/clav or cephalosporin) x5-7 days
Ciprofloxacin or levofloxacin x 3 days *
*Quinolones: do NOT use in children, pregnant patients, those with seizures, neuropathy, or QT prolongation risk; watch for tendinitis/rupture and BG changes (esp in DM pts)
Treatment options for acute uncomplicated cystitis in pregnant patients
Amoxicillin
Cephalexin
Beta-lactam allergy: Fosfomycin
Duration: 7 days
Treatment options for Acute pyelonephritis, moderately ill outpatient if local quinolone resistance ≤ 10%
Cipro or levofloxacin x5-7 days
Concerns for quinolone adverse effects: SMX/TMP or beta-lactam (amox/clav, cefdinir, cefadroxil, cefpodoxime) x7-10 days
Treatment options for Acute pyelonephritis, moderately ill outpatient if local quinolone resistance > 10%
CTX, ertapenem, or aminoglycoside extended-interval dose x1 + quinolone (cipro, levo) x5-7 days
Concerns for quinolone adverse effects: SMX/TMP or beta-lactam (amox/clav, cefdinir, cefadroxil, cefpodoxime) x7-10 days
Treatment options for Acute pyelonephritis, severely ill hospitalized patient
Initial: CTX or quinolone (cipro, levo)
Concern for resistance: pip/tazo or a carbapenem (if ESBL-producing organism suspected)
Step-down according to culture + susceptibility
Duration 5-10 days depending on regimen and clinical response
Do not use ____ for UTIs (does not reach high levels in the urine)
Moxifloxacin
Acute pyelonephritis, risk for or documented pseudomonas infection, which abx to consider?
Pip/tazo or antipseudomonal carbapenem (meropenem, doripenem, imipenem/cilastatin)
____ can help with dysuria (pain/burning with urination) but does not treat the infection
Phenazopyridine (Pyridium, Azo Urinary Pain Relief)
Dosing for phenazopyridine
200 mg PO TID x2 days (max)
Take with 8 oz of water, with food to minimize stomach upset
Contraindications for phenazopyridine
Do NOT use in renal impairment of liver disease
Patient counseling points for phenazopyridine
Max duration: 2 days
Take with 8oz of water and with food to minimize stomach upset
Can cause red-orange coloring of the urine and other body fluids; contact lenses/clothes can be stained
T/F: Bacteriuria alone indicates abx treatment in all patients
False - unless they are symptomatic you don’t give abx for just bacteriuria (exception pregnant pts regardless of symptoms
Preferred treatment for bacteriuria in pregnant patients
Amoxicillin ± clavulanate or an oral cephalosporin
Beta-lactam allergy: nitrofurantoin, SMX/TMP, or fosfomycin (nitrofurantoin, SMX/TMP reserve when other options not available, avoid in 1st trimester if possible // avoid SMX/TMP in 3rd trimester if possible, can cause hyperbilirubinemia and kernicterus in newborn if used close to delivery)
Which abx should be avoided in pregnant patients with bacteriuria
Quinolones (cartilage toxicity and arthropathies)
S/sx C.diff infection
at least 3 watery stools per day
abdominal cramps
Fever
Elevated WBC count
What are some risk factors of C. diff infection
Healthcare exposure, use of PPIs, advanced age, immunocompromised state, obesity, and previous CDI
How to dx C. diff infection
Positive C. diff stool toxin or PCR
Bezlotoxumab can be added on to a CDI regimen for high risk patients which include:
≥65 yo, immunocompromised status, severe presentation, and/or experiencing 2nd episode of CDI within past 6 months
Treatment for CDI: 1st episode
Fidaxomicin 200mg PO BID x 10 days OR
Vancomycin 125 mg PO QID x 10 days OR
Metronidazole 500mg PO TID x 10 days (option only if non-severe and treatments above are not available)
Treatment for CDI: 2nd episode
Fidaxomicin 200mg PO BID x 10 days OR
Vancomycin 125mg PO QID x 10 days + taper (normal course acceptable if metronidazole was used for 1st episode)
Treatment for CDI: 3rd episode or subsequent episodes
Fidaxomicin 200mg PO BID x 10 days OR
Vancomycin 125mg PO QID x10 days + taper OR
Vancomycin 125mg PO QID x 10 days + rifaximin 400mg TID x20 days OR
Fecal microbiota transplantation
Treatment for CDI: Fulminant/complicated disease (dx when sig systemic toxic effects such as hypotension, shock, ileus, or toxic megacolon)
Vancomycin 500mg PO/NG/PR QID + metronidazole 5400mg IV q8h
S/sx of common STIs: chlamydia
Genital discharge or no symptoms
S/sx of common STIs: gonorrhea
Genital discharge or no symptoms
S/sx of common STIs: genital warts
single or multiple pink/skin-toned lesions
S/sx of common STIs: latent syphilis
Asymptomatic
S/sx of common STIs: primary syphilis
Painless, smooth genital sores (Chancre)
S/sx of common STIs: bacterial vaginosis
vaginal discharge (clear, white or gray) that has a “fishy” odor and pH > 4.5; little o no pain
S/sx of common STIs: Trichomoniasis
Yellow/green, frothy vaginal discharge with pH >4.5; soreness, pain with intercourse
Treatment: Syphilis (primary, secondary, or early latent) drug of choice and dosing
Penicillin G benzathine (Bicillin L-A, do NOT sub with Bicillin C-R)
2.4 million units IM x1
Treatment: Syphilis (primary, secondary, or early latent) beta-lactam allergy
Doxycycline 100mg PO BID x14 days
If pregnant, nonadherent with treatment, or unlikely to f/u, desensitize and treat with Bicillin L-A (PCN G benzathine)
Dx syphilis
Positive non-treponemal test (rapid plasma reagin (RPR) or Venereal Disease Research Lab (VDRL) blood test) and treponemal assay
Treatment: Syphilis (late latent or tertiary) drug of choice and dosing
Penicillin G benzathine 2.4 million units IM weekly x3 weeks (7.2 million units total)
Treatment: Syphilis (late latent or tertiary) beta-lactam allergy
Doxycycline 100mg PO BID x28 days
If pregnant, nonadherent with treatment, or unlikely to f/u, desensitize and treat with Bicillin L-A (PCN G benzathine)
Treatment: neurosyphilis
Penicillin G aqueous crystalline 3-4 million units IV q4h x10-14 days
Alt: Penicillin G procaine
Beta-lactam allergy: desensitization followed by administration of penicillin G aqueous IV
Treatment: Gonorrhea drug of choice and dosing
CTX 500mg IM x1 (if ≥150kg, increase dose to 1g IM x1)
If chlamydia has not been excluded: add doxycycline
Treatment: Gonorrhea drug of choice and dosing, pregnant pts
Same
CTX 500mg IM x1 (if ≥150kg, increase dose to 1g IM x1)
If chlamydia has not been excluded: add doxycycline
Treatment: Gonorrhea alternatives
If CTX not available: cefixime 800mg PO x1
If cephalosporin allergy: gentamicin 240mg IM x1 + azithromycin 2g POx1
Note: CTX is most effective for pharyngeal infections
Treatment: Chlamydia drug of choice, non-pregnant
Doxycycline 100mg PO BID x7 days
Treatment: Chlamydia drug of choice, pregnant
Azithromycin 1g PO x1
Treatment: Chlamydia alternatives
Erythromycin base 500mg PO QID x7 days OR
Levofloxacin 500mg PO daily x7 days
Pregnancy: amoxicillin 500mg PO TID x7 days
Treatment: Bacterial vaignosis drug of choice and dosing
Metronidazole 500mg PO BID x7 days OR
Metronidazole 0.75% gel intravaginally daily x 5 days OR
Clindamycin 2% cream intravaginally at bedtime x 7 days
Treatment: Bacterial vaginosis alternatives
Clindamycin 300mg PO BID x7 days (or clindamycin ovules 100mg intravaginally at bedtime x3 days) OR
tinidazole 2g PO daily x2 days (or 1 g PO daily x 5 days) OR
Secnidazole 2g PO x1 dose
T/F: females with bacterial vaginosis should regularly clean their vaginas such as using a douche
False - females with bacterial vaginosis should NOT douche
Treatment: Trichomoniasis drug of choice and dosing
Metronidazole
Females: 500mg PO BID x7 days
Males: 2g PO x1
Treatment: Trichomoniasis, pregnant
Metronidazole (per package labeling contraindicated in 1st trimester but based on safety data CDC recommends safe in all trimesters)
Treatment: Genital warts
Imiquimod cream (Aldara, Zyclara) apply topically to clean, dry, warty tissue and wash off in 6-10 hours
Apply 3x/week until cleared (or 16 weeks)
T/F: Genital wart treatment is required even if asymptomatic
False - warts generally resolve spontaneously within 1 year
____ vaccine reduces the risk of genital warts as well as cervical and other cancers
Gardasil
Genital warts are often caused by ___ strains __ and __
HPV strains 6 and 11
____ is the most common tickborne disease and most fatal of these illnesses in the US
Rocky Mountain spotted fever
S/sx of Rocky Mountain spotted fever
fever, HA, muscle pain, followed 3-5 days later by an erythemateous petechia rash (pinpoint or splotchy red spots caused by bleeding into the dermis)
Treatment: Rocky Mountain Spotted fever
Doxycycline 100mg PO/IV BID x5-7 days (drug of choice, even in pediatric patients)
What bacteria causes Rocky Mountain Spotted Fever?
Rickettsia rickettsii
GN obligate intracellular bacteria
Treatment: Lyme Disease
Doxycycline 100mg PO BID x10 days OR
Amoxicillin 500mg PO TID x14 days OR
Cefuroxime 500mg PO BID x14 days
What bacteria causes lyme disease?
Borrelia burgdorferi, Borrelia mayonii
Spirochetes
Treatment: Ehrlichiosis
Doxycycline 100mg PO/IV BID x7-14 days
What bacteria causes ehrlichiosis?
Ehrlichia chaffeensis
Obligate intracellular bacteria
How to tell between lyme disease vs ringworm
Lyme disease: bacterial
Lyme disease s/sx: “bull’s-eye” rash (round, red with central clearing as it expands), achy joints, fever
Ringworm: fungal infection (Tinea corporis)
Ringworm s/sx: 1+ reddish, raised rings, can be itchy
