Common ID Syndromes March 2014

objectives Identifying the bug Choosing the antibiotics Empiric coverage for common ID scenarios

Basics Try to collect cultures before starting antibiotics Renally dose antibiotics (esp Vanco, levaquin) Call the ID fellow for approval when required Use Sanford Guide and hospital antibiograms Sanford Guide now has a mobile app Epocrates app also has useful guides

Consider your bugs! What are you treating or covering empirically?

Common ID Syndromes (covered in this lecture) Bacterial Meningitis Infective Endocarditis Clostridium Difficile Urinary Tract Infections Cellulitis CAP & HCAP (covered elsewhere)

Bacterial Meningitis Common causes of meningitis: Diagnosis: LP S. pneumoniae (30-50%) Neisseria meningitidis (10-35%) Listeria (2-11%) Other less common include: Gram-negative; Streptococci; Staphylococci; H. influenzae Diagnosis: LP Gram stain, C&S, cell count w/ diff, protein, and glucose Empiric treatment for Suspected Bacterial Meningitis 3rd gen cephalosporin (ceftriaxone or cefotaxime), PLUS Vancomycin, +/- Ampicillin (if at risk for Listeria: age >60 or neonate)

Infective Endocarditis Obtain 3 sets of blood cultures Diagnosis: Modified Duke Criteria Definite endocarditis: Pathologic evidence of disease OR 2 Major clinical criteria OR 1 Major + 3 minor OR 5 minor Possible endocarditis 1 Major + 1 minor OR 3 minor Pathologic evidence of disease (on Echo with vegetation or valve lesion or +culture from same tissue)

IE Major and minor criteria Major Criteria 1) Positive blood cultures (specific criteria) “Typical” organisms: S. aureas, viridans strep, S. Bovis, enterococci, and HACEK 2) Abnormal echocardiogram Minor Criteria 1) Predisposing condition (valve disease or IVDA) 2) Fever 3) Vascular phenomena 4) Immunologic phenomena 5) Positive blood culture that does not meet a major criterion Major criterion: organisms should be “typical” (S. aureas, viridans strep, S. Bovis, enterococci, HACEK) from 2 separate cultures at least 12 hours apart - If suspecting HACEK, call lab for slow-growing organisms 2. Any other organisms should be in at least 3 or a majority of 4 or more cultures 3. Any 1 blood culture that grow C. burnetti is significant

Treatment of IE Organisms Susceptibility Drug Regimen Duration Viridans streptococci, S. Bovis PCN-sensitive PCN G or CTX 4 weeks Prosth >4 weeks (PCN G or ctx) + gent 2 weeks Vancomycin (alt) PCN-resistant Increased dose PCN G S. Aureus or Coagulase-neg Methicillin-susc Nafcillin 6 weeks Prosthetic (add rifampin & gent) Methicillin-resis Vancomycin Staph, uncomplicated right-sided Nafcillin + gentamicin or daptomycin Enterococci PCN-sens (PCN G or amp or vanc) + gent 4-6 weeks Prosth = 6 weeks Amp + PCN + Vanc-resis Very specialized HACEK Ceftriaxone Source MedStudy 15th edition Enterococci resistant to amp, PCN G, vanc  utilize variations of linezolid and imipnem/cilastin with either amp or ceftriaxone

Diarrhea due to C. difficile Common causes: Clindamycin, cephalosporins, quinolones Diagnosis: Confirm with stool assay for cytotoxin Recommendations: Mild-to-moderate: Flagyl 500mg po tid x 10-14 days Severe disease: Vanco 125mg po qid x 10-14 days Severe with complications: P.O. Vanco +/- IV Flagyl 1st relapse: Repeat the first regimen 2nd relapse: Vanco 125mg po qid and taper

Urinary tract infection Microbiology for uncomplicated UTI: E. coli (most common 75-95%) Other species of Enterobacteriaceae: Proteus mirabilis (associated with stones, do add’l workup) Klebsiella pneumoniae Staphylococcus saprophyticus Group B strep (in pregnant women, otherwise contaminant) Likely contamination in healthy non-pregnant individuals: (lactobacilli, enterococci, coag-neg staph) Broader for complicated (pseudomonas, serratia, providencia species, enteroccci, stapylococci, fungi)

Urinary Tract Infection Acute uncomplicated cystitis-urethritis Bactrim 160/800 (1 DS tab) bid x 3 days OR Macrobid 100mg bid x 5 days OR Fosfomycine 3g po (single dose) Uncomplicated pyelonephritis Ciprofloxacin 500mg bid x7 days OR Ceftriaxone or quinolone (if requiring IV) Complicated pyelonephritis Ceftriaxone, cefepime, aztreonam, or quinolone Add expanded coverage if ICP or urinary obstruction Asymptomatic bacteruira: treatment indicated only in pregnant women and men/women undergoing invasive urologic procedures Acute complicated UTI is associated with an underlying condition that increases the risk of infection or of failing therapy (such as obstruction, anatomic abnormality, urologic dysfunction, or a multiply-resistant uropathogen; progression of upper UTI to emphysematous pyelonephritis, renal corticomedullary abscess, perinephric abscess, or papillary necrosis.

Cellulitis Purulent (drainage or exudate w/o drainable abscess) – d/t community-acquired MRSA Clindamycin 300-450mg po tid Bactrim 1 DS tab bid Doxycycline 100mg bid Minocycline 200mg x1, then 100mg bid Linezolid 600mg bid Non-purulent – d/t beta-hemolytic strep and MSSA Systemic toxicity requires parenteral antibiotics Standard empiric treatment includes coverage for both MRSA and beta-hemolytic streptococci (options: Clindamycin; Amoxicillin + Bactrim or tetracyclin; Linezolid) PO IV Dicloxacillin 500mg q6h Cefazolin 1-2g q8h Keflex 400mg q6h +/- Bactrim Oxacillin 2g q4h Clindamycin 300-450mg q6h Nafcillin 2g q4h Clindamycin 600-900mg q8h

Antibiotic Coverage Quick Guide 1. Pseudomonas: Zosyn Aminoglycosides Cephalosporins: Ceftazidine, Cefepime Fluoroquinolones: Cipro, Levaquin Carbipenems: Imipenem, Meropenem Aztreonam Colistin 3. MRSA: Bactrim Clindamycin Doxycyclin Vancomycin Linezolid Tigecycline Daptomycin – cannot use in lungs! 4. VRE: Linezolid Tigecycline Daptomycin 2. Anaerobes: Flagyl Clindamycin Zosyn Unasyn Augmentin Carbipenem Moxifloxacin Tigecycline

Take home points Deescalate antibiotics based on sensitivities Antibiotics should be individualized based on patient circumstances (allergy, tolerability, compliance), local community resistance prevalence, availability, cost, and patient and provider threshold for failure