Infectious Diseases II: Bacterial Infections Flashcards
Perioperative Antibiotic Prophylaxis
Bug and Drug of Choice, Alternatives
Bug: Staphylococci and Streptococci
——Drugs——–
DOC: Cefazolin*** or Cefuroxime
Alt: Vancomycin or Clindamycin
- used when a beta-lactam allergy or risk of MRSA
Time of Perioperative Antibiotics
pg. 376
—-Pre-operative (prior to surgery)—-
DOC: 60 min before Alt: 120 min before
—-Intra-operative (during surgery)—-
Additional doses may be administered if surgery is >3-4
hours or there is major blood loss
—-Post-operative (after surgery)—-
ABX not usually needed; if used, discontinue within 24 hours
Surgery prophylaxis DOC & bug coverage
DOC: Cefazolin (1st gen ceph) - MRSA and Streptococci
Alt: Clindamycin if pt has a beta-lactam allergy or Vancomycin (MRSA colonization or risk instead of Clindamycin)
Colorectal surgery prophylaxis DOC vs alternatives & bug coverage
DOC: Cefotetan, cefoxitin, ampicillin/sulbactam (Unasyn), ertapenem, OR metronidazole PLUS cefazolin or ceftriaxone
Alt: Clindamycin PLUS (aminoglycoside, quinolone or aztreonam), OR metronidazole PLUS (aminoglycoside or quinolone)
Classic symptoms of meningitis
Fever
Headache
Stiff neck
Altered mental status
Meningitis Diagnosis & Bugs
Dx: Lumbar puncture
Bugs: S. pneumoniae, N. meningitidis, H. influenzae, Listeria
Acute Bacterial Meningitis Treatment (Community-Acquired)
ABX durations are pathogen-dependent
7 days for N. meningitidis and H. influenzae
10-14 days for S. pneumoniae
<21 days for Listeria monocytogenes
Meningitis: Empiric Treatment
Empiric antibiotic selection depends of age & RFs
Aggressive (high) doses are used to penetrate the CNS
——–Age < 1 month (neonates)——–
Ampicillin (Listeria) PLUS cefotaxime (no ceftriaxone) OR gentamicin
- ——-Age 1 month to 50 years———
- Ceftriaxone or cefotaxime PLUS vancomycin
——–Age > 50 years or immunocompromised———–
Ampicillin (Listeria) PLUS Ceftriaxone or Cefotaxime PLUS Vancomycin
Meningitis: Empiric Treatment but the adult has a severe penicillin allergy
Treat with a Quinolone (moxifloxacin) PLUS vancomycin +/- Bactrim (listeria coverage)
S/SX of AOM
Bulging tympanic (eardrum) membranes
Otorrhea (middle ear effusion/fluid)
Otalgia (ear pain)
Tugging/rubbing of ears
AOM Treatment in Kids: When to consider observation
Systemic drugs: Pain (APAP or Ibu)
Observation for 48-72 hours - non-severe AOM
-mild otalgia < 48 hours or temp <102.2F (39)
AND
Age 6-23 months: sx in one ear only
Age > 2 years: sx in one or both ears
**if sx do not improve, or worsen, use ABX
AOM Antibiotic Treatment
High-dose amoxicillin or amoxicillin/clavulanate (Augmentin)
**least amount of clavulanate - decrease risk of diarrhea
H-D covers S. pneumoniae
What is the ratio of amoxicillin to clavulanate? What’s the brand?
14:1 - Augmentin ES 600
American Academy of Pediatrics (AAP) guidelines recommended what drug class for non-severe penicillin allergy?
Cephalosporin
Treatment duration with oral medications
10 days for children < 2 years
7 days for age 2-5 years
5-7 days for age > 6 years
AOM: Antibiotic Treatment
——-First-Line Treatment———
Amoxicillin 80-90 mg/kg/day in 2 divided doses
OR
Amoxicillin/clavulanate 90 mg/kg/day
OR
Ceftriaxone IM (if vomiting or unable to tolerate PO)
——-Alternative Treatment———-
Cefdinir 14 mg/kg/d in 1-2 divided doses
Cefuroxime 30mg/kd/d in 2 divided doses
Compare and Contrast - Clinical Presentation
Common cold
Influenza
Pharyngitis
Sinusitis
pg. 379
———Clinical Presentation———–
C: sneezing, runny nose, cough
I: sudden onset fever, chills, fatigue, body aches
P: sore throat, swollen lymph nodes, white patches on tonsils
S: nasal congestion, facial/ear/dental pain, headache
Compare and Contrast - Criteria for Anti-Infective Treatment
Common cold
Influenza
Pharyngitis
Sinusitis
pg. 379
———Criteria for Anti-Infective Treatment—–
C: none
I: < 48 hours since sx onset
P: rapid antigen diagnostic test
S: > 10 days of sx OR > 3 days of severe sx (temp >102*F)
Compare and Contrast - Treatment Options
Common cold
Influenza
Pharyngitis
Sinusitis
pg. 379
C: OTC products
I: Oseltamivir x 5 days | Baloxavir x 1 dose | Zanamivir inhalation
P: Penicillin, amoxicillin
Sinusitis:
1st line - Augmentin
2nd line - PO 2nd/3rd gen ceph PLUS clindamycin, doxycycline or resp. FQ
Lower Respiratory Tract Infections - Bronchitis
Symptoms
Cause
Diagnosis
Treatment of Choice
Bronchitis
Symptoms: cough
Cause: RSV or bacteria (Bordetella pertussis ‘whooping cough’)
Diagnosis: chest x-ray
Treatment of Choice: supportive care (fluids, otc meds. abx not recommended “exception is Bordetella - macrolide or bactrim) “
COPD patient with Acute Bacterial Exacerbation of Chronic Bronchitis
- Supportive treatment (O2, short-acting inhaled
bronchodilators, IV/PO steroids) - ABX for 5-7 days if any one of the following are met:
- increase dyspnea, incr. sputum volume and incr. sputum purulence
- mechanically ventilated - Preferred ABX
- Augmentin**
- Azithromycin
- Doxycycline
Community-Acquired Pneumonia
Symptoms
Diagnosis
Common pathogens
Treatment of Choice & Duration
Community-Acquired Pneumonia
Sx: cough, purulent sputum, rales, tachypnea (incr. RR)
Dx: Chest X-ray
Bugs: S. pneumonia, H. influenzae, M. pneumoniae “walking pneumonia”
DOC: Respiratory FQs x 5-7 days
Outpatient CAP Treatment Stepwise Approach
Step 1: look for comorbidities (chronic heart, lung, liver, kidney disease, DM, alcoholism, malignancy or asplenia)
Step 2: check for MRSA or Pseudomonas
Step 3: Category 1 vs Category 2
Step 4: Choose DOC within category (look for allergies/DDIs)
Outpatient CAP Treatment Stepwise Approach
Category 1
No comorbidities
Amoxicillin H-D 1g TID OR Doxycycline OR Macrolide (Azithromycin or clarithromycin)
Outpatient CAP Treatment Stepwise Approach
Category 2
Beta-lactam PLUS macrolide OR doxycycline
- augmentin OR cephalosporin (cefpodoxime, cefuroxime) PLUS - macrolide OR doxycycline
Respiratory quinolone monotherapy - moxifloxacin, gemifloxacin, levofloxacin
Inpatient CAP treatment for nonsevere (non-ICU care)
Beta-lactam PLUS macrolide OR doxycycline
- preferred beta-lactams (Ceftriaxone, cefotaxime, ceftaroline or Unasyn)
Respiratory quinolone monotherapy
- moxifloxacin, gemifloxacin, levofloxacin
Inpatient CAP treatment for severe (ICU care)
Beta-lactam PLUS macrolide
Beta-lactam PLUS respiratory quinolones (do NOT use FQ monotherapy)
Risk factors for Pseudomonas and/or MRSA in Inpatient CAP treatment:
MRSA: add coverage with Vancomycin or Linezolid
Pseudomonas: add coverage with zosyn, cefepime, meropenem or aztreonam
Hospital-acquired pneumonia (HAP) has an onset of
onset > 48 hours after hospital admission
Ventricular-associated pneumonia (VAP) occurs
> 48 hours after the start of mechanical ventilation
Common pathogens in HAP and VAP
Nosocomial pathogens
Risk for MRSA and MDR Gram-negative rods, including Pseudomonas
HAP/VAP: Selecting an Empiric Regimen
All patients need an antibiotic for Pseudomonas and MSSA regimen:
cefepime
piperacillin/tazobactam (Zosyn)
HAP/VAP: Selecting an Empiric Regimen
If patient is at risk for MRSA what drugs are added?
Vancomycin or Linezolid
- cefepime PLUS vancomycin
- meropenem PLUS linezolid
HAP/VAP: Selecting an Empiric Regimen
What 2 antibiotics are used in Pseudomonas if risk for MDR pathogens?
-piperacillin/tazobactam PLUS ciprofloxacin PLUS
vancomycin
-cefepime PLUS gentamicin PLUS linezolid
Identify the risks for MRSA or MDR pathogens
- Positive MRSA nasal swab (indicates MRSA colonization)
- High prevalence (>10%) of pathogen resistance to any single agent noted in hospital unit
- IV antibiotic use within the past 90 days
Antibiotics for Pseudomonas (do NOT use 2 beta-lactams together)
piperacillin/tazobactam cefepime, ceftazidime, or ceftolozane/tazobactam (Zerbaxa) levofloxacin or ciprofloxacin imipenem/cilastatin or meropenem aztreonam tobramycin, gentamicin or amikacin colistimethate or polymyxin B
Antibiotics for MRSA
vancomycin
linezolid
How is active pulmonary TB spread?
transmitted aerosolized droplets (i.e., sneezing, coughing & talking)
Highly contagious
Clinical presentation of active pulmonary TB
cough/hemoptysis (coughing up blood)
fever
night sweats
Hospitalized patients require isolation in a single negative-pressure room
Diagnosis of TB
Latent disease: TB skin test (PDD)
- intradermal injection, analyzed after 48-72 hours
Diagnosis of Latent TB: Criteria for Positive TB Skin Test Results
≥ 5 mm induration = significant immunosuppression
≥ 10 mm induration = high-risk congregate settings (healthcare workers)
≥ 15 mm induration = patients with no risk factors
Latent TB Treatment duration
Shorter regimens (3-4 mo) preferred** due to higher completion rates and less risk of hepatotoxicity
Preferred Latent TB Regimens - Drugs/Duration
- INH and Rifapentine - weekly x 12 weeks via directly observed therapy (DOT) ‘adherence’
do not use this regimen in pregnancy
- Rifampin x 4 months (preferred in children of all ages & HIV-negative adults)
- Isoniazid w/ rifampin x 3 months (use in adults, children & HIV +)
Alternate Latent TB Regimens - Drugs/Duration
- INH x 6-9 months (alternate for HIV -/+ adults/children)
INH x 9 months in pregnancy (Tx of choice)
Active TB Diagnosis
A positive TST and confirmed with an acid-fast bacilli (AFB) statin
Active TB Treatment
2 phases (intensive and continuation)
Intensive “RIPE x 2 months”
Continuation phase x 4 months (2 drugs: rifampin & isoniazid)
RIPE Drugs
rifampin (RIF)
isoniazid (INH)
pyrazinamide (PZA)
ethambutol
Duration: 8 weeks (2 mo)
Rifampin - Safety/SE/Monitoring
SE: increase LFTs, hemolytic anemia (detected with a positive Coombs test), flu-like syndrome, orange-red discoloration (sputum, urine, sweat, tears, teeth), stain contacts & clothes
DDI:
-RIF is a potent inducer of CYP450 and P-glycoprotein
- decrease concentration of PI, Warfarin (decr. INR),
OC (decr. efficacy)
- Do NOT use RIF w/ apixaban, rivaroxaban
Alternative to rifampin is rifabutin (less DDIs)
Isoniazid - Safety/SE/Monitoring/Notes
Boxed Warning: hepatitis
Warnings: Peripheral neuropathy
Notes: Supplement with pyridoxine (Vit B6) 25-50 mg to decr. risk of peripheral neuropathy
SE: increase LFTs, drug-induced lupus erythematosus (DILE), hemolytic anemia (+ Coombs test)
Pyrazinamide - Safety/SE/Monitoring/Notes
Contraindications: acute gout
SE: increase LFTs, hyperuricemia/gout
Ethambutol - Safety/SE/Monitoring/Notes
SE: increase LFTs, optic neuritis (dose-related), confusion, hallucinations
RIPE Therapy for TB (Drug-Specific Key Points)
Monitor infection: sputum samples, sx, and chest x-ray
All RIPE drugs: increase LFTs
———–Rifampin————
orange bodily secretions
strong CYP450 inducer (use rifabutin if CI)
flu-like symptoms
———–Isoniazid————
peripheral neuropathy; give w/ pyridoxine (Vit B6) 25-50 mg PO daily
monitor for sx of DILE
———–RIF & INH———–
risk of hemolytic anemia (+ Coombs test)
——–Pyrazinamide——–
increase uric acid - do not use with acute gout
——–Ethambutol———–
visual damage (requires baseline & monthly vision exams)
confusion/hallucinations
Infective endocarditis - Diagnosis & Common Pathogens
Dx: ECG & positive cultures
Pathogens: Staphylococci, Streptococci & Enterococci
What drug is added for synergy effect in Infective Endocarditis? Monitoring?
Gentamicin
Pathogens: active against Pseudomonas and enhances Gram-positive coverage with used as synergy
Monitoring: peak levels 3-4 mcg/mL & troughs <1 mcg/mL
Preferred ABX Regimen in infective endocarditis treatment associated with which pathogen?
Viridans group Streptococci: PCN or ceftriaxone (+/- Gent)
Staphylococci (MSSA): NAF or cefazolin (+ Gent & RIF ‘if prosthetic valve’)
use Vanc if beta-lactam allergy
Staphylococci (MRSA): Vancomycin (+ Gent & RIF ‘if PV’)
Enterococci: Both native & prosthetic valve IE
- PCN or ampicillin + gent OR ampicillin + high-dose ceftriaxone
beta-lactam allergy: Vanc + Gent
^^ if VRE, use daptomycin or linezolid ^^
Infective endocarditis dental prophylaxis
Adult Prophylaxis Regimen
PO: Amoxicillin 2 g 30-60 min b4 dental procedure
**if can’t do PO: Ampicillin 2g IM/IV OR Cefazolin 1 g IM/IV
^^ if allergic to PCN: Clindamycin 600 mg
OR
Azithromycin/Clarithromycin 500 mg
**if can’t do PO & PCN allergy: Clindamycin 600 mg IM/IV
Intra-abdominal infections
DOC in spontaneous bacterial peritonitis (SBP)
Pathogens for Primary & Secondary Peritonitis
DOC: Ceftriaxone x 5-7 days
Prophylaxis for SBP: Bactrim or Cipro
Primary Peritonitis: Streptococci, enteric Gram-negative (Proteus, E.coli, Kleb, or PEK)
Secondary Peritonitis: “same” PLUS anaerobes (B. fragilis) - DOC: Flagyl
Intra-abdominal infections
Define Cholecystitis vs Cholangitis
Cholecystitis: inflammation of the gallbladder
Cholangitis: infection of the common bile duct
Skin & Soft Tissue - Clinical Presentation & Classifications
Mild: Superficial (impetigo, furuncles, carbuncles)
Moderate: Non-purulent cellulitis
Severe: Purulent/Abscesses
Systemic Signs:
- Temp > 100.4*F
- HR > 90 BPM
- WBC > 12000 < 4000 cells/mm^3
Outpatient Treatment of MSSA/MRSA & Streptococci SSTIs
Impetigo
Honey-colored crusts
DOC: mupirocin (Bactroban)
**if numerous lesions, use PO abx for MSSA: Keflex
Outpatient Treatment of MSSA/MRSA & Streptococci SSTIs
Folliculitis/furuncles/carbuncles
Follicles & Furuncles: warm compress
Carbuncles require incision & drainage ((&D)
- *if systemic signs, PO for MSSA: Keflex
- *if unresponsive to initial treatment, change to CA-MRSA: Bactrim or Doxy
Mild Cellulitis (Non-purulent) SSTI
PO abx must be active againists Streptococci + MSSA
DOC: Keflex
Alt: Clindamycin
Mild-Moderate purulent SSTI
Commonly caused by CA-MRSA
1st-line: I&D
**if systemic signs or multiple sites: I&D PLUS Bactrim or Doxy
Severe purulent SSTI Treatment
Cover MRSA + CA-MRSA
Vancomycin (goal trough 10-15 mcg/mL)
Daptomycin**
Linezolid**
**VRE coverage
Necrotizing fasciitis Treatment
Empiric therapy is broad: Vanc + beta-lactam
Beta-lactam: piperacillin/tazobactam (Zosyn), imipenem/cilastatin or meropenem)
What are the aerobic Gram-positive pathogens?
S. aureus (MRSA)
Group A Streptococcus
Viridans group Streptococci
S. epidermidis
What are the aerobic Gram-negative pathogens?
E. coli K. pneumoniae P. mirabilis Enterobacter cloacae Pseudomonas
What are the anaerobic Gram-positive pathogens?
Peptostreptococcus
Clostridium perfringens
What are the anaerobic Gram-negative pathogens?
Bacteroides fragilis and faecium
Urinary Tract Infection (UTI) Symptoms
-------Cystitis (Lower UTI)------- urgency and frequency (nocturia) dysuria suprapubic heaviness hematuria ----Pyelonephritis (Upper UTI)---- flank pain ----Vaginal Candida albicans "fungal infection"---- itchy
Uncomplicated UTIs occur in what population(s)?
non-pregnancy women
Complicated UTIs occur in what population(s)?
Males
Patients with indwelling catheter
Children
Does the presence of bacteria alone qualify to be diagnosis as a UTI?
No
Urinalysis must confirm pyuria & bacteriuria
Exception: asymptomatic bacteriuria in pregnancy
Drugs of Choice in Acute Uncomplicated Cystitis
Macrobid 100 mg PO BID x 5 days (CI: CrCl < 60 mL/min)
OR
Bactrim DS 1 tab PO BID x 3 days
OR
Fosfomycin 3 g x 1 dose
What are the drugs of choice in pregnancy with acute uncomplicated cystitis?
Keflex & Amoxicillin x 7 days
**PCN allergy: Fosfomycin
Which quinolone is not used in UTIs?
Moxifloxacin
it’s only available in retail as antibiotic eye/ear drops
What is the class of choice in Complicated UTI if ESBL-producing bacteria is present?
Carbapenems
Phenazopyridine - Brand & Counseling Points
Brand: Pyridium or AZO
CP: max 2 days, take with 8 oz of water or food to decr. GI upset, may cause red-orange coloring of urine; contact lense/clothes staining
Common pathogens of Travelers’ Diarrhea
-----Bacterial------ E. coli Campylobacter jejuni Shigella Salmonella
Viral: Rotavirus
Travelers’ Diarrhea Treatment
Azithromycin preferred treatment if fever, blood in stools, pregnant or pediatric
Quinolones (1-3 days) or rifaximin (3 days) if bloody diarrhea is not present
Antimotility agents: Loperamide (for symptomatic relief only)
Symptoms of C. difficile infection (CDI)
Abdominal cramps Profuse diarrhea (can be bloody) Fever
C. difficile guideline recommendations for treatment
- ———1st episode (nonsevere or severe)——-
- Vancomycin 125 mg PO QID x 10 days OR
- Fidaxomicin 200 mg PO BID x 10 days
- *if non-severe and above treatment not available
- Metronidazole 500 mg PO TID x 10 days
——–Fulminant/Complicated 1st episode——-Vancomycin 500 mg PO/NG/PR QID + Flagyl 500 mg IV Q8H
- ——2nd episode “Recurrence”————
- If MET used initially: Vanc 125 mg PO QID x 10 days
- If VANC used initially: FDX 200 mg PO BID x 10 days
- If VANC or FDX used initially: Vanc tapered and pulsed regimen** (125 mg QID x 10 days, BID x 1 week, daily x 1 week, then 125 mg Q2-3 days x 2-8 weeks)
——-Subsequent Episodes———–
VANC taperer and pulsed regimen** OR
VANC 125 mg PO QID x 10 days,
then rifaximin 400 mg TID x 20 days OR
FDX 200 mg PO BID x 10 days OR
Fecal microbiota transplant
Syphilis (primary, secondary or early latent)
Treatment of Choice, Dosing/Duration & Alternatives
DOC: Bicillin L-A
Dosing/Duration: 2.4 million units IM x 1
Alternatives: Doxycycline
If allergic to PCNs (desensitized and treat with Bicillin L-A)
- HIV
- Pregnancy
Syphilis (late latent or tertiary)
Treatment of Choice & Dosing/Duration
DOC: Bicillin L-A
Dosing/Duration: 2.4 million units IM x 3 weeks
Neurosyphilis and congenital syphilis DOC
Pen G
Gonorrhea DOC
Ceftriaxone
< 150 kg: 500 mg IM x 1
> 150 kg: 1 g IM x 1
If Chlamydia has not been excluded: add Doxycycline
Chlamydia DOC
Doxycycline 100 mg PO BID x 7 days
OR
Azithromycin 1 g PO x 1
Bacterial Vaginosis DOC
Metronidazole PO or 0.75% gel
Trichomoniasis DOC
Metronidazole 2 g PO x 1
CDC recommended Flagyl in all trimesters (even though MET is CI in 1st trimester)
Genital Warts (HPV) DOC
Imiquimod cream
What is the drug of choice in rickettsial diseases?
DOC: Doxycycline
DOC esp. pediatrics
