Things your mother never told you about antibiotics Rob Kaplan, MD July 8 and 9, 2015

Objectives After this talk participants will: –Be able to articulate some of the principles and pitfalls of antibiotic use –Have a working approach to antibiotic selection for some common infections –Probably choose to subspecialize in infectious diseases

Common misconceptions/distortions about antibiotics

1. “Let’s just throw in some antibiotics-it can’t hurt…”

1. The Problem… Microbiome change->C. diff and other superinfections, resistance in patient and community Allergic and nonallergic drug toxicities Cost (materials,labor, indirect costs) Diagnostic pitfalls (impaired cultures, early closure, etc.)

2. Clindamycin above the diaphragm, metronidazole below the diaphragm…

2. The Problem… Both have activity against strict anaerobes with metronidazole superior Clindamycin has activity against some Gram + aerobes so it can stand alone for infections caused by oral flora But the gap is filled when metronidazole combined with a penicillin And clinda has a heightened C. diff risk

3. With the high prevalence of MRSA, Vancomycin should be used for all severe Staph infections…

3. Why not?

4. Osteomyelitis should be treated for 6 weeks with IV antibiotics…

4. Not necessarily… Antibiotics can be stopped soon after definitive surgery. Sometimes therapy needs to be extended if active inflammation remains. Sometimes the wisest choice is brief therapy for soft tissue infection or no therapy at all!

5. I don’t feel comfortable changing from the empiric regimen because the patient is doing well…

5. Let me help you with this… What does empiric therapy mean? What is the other kind of therapy? Why do we change regimens when a patient is dong poorly? Why do we change regimens when a patient is doing well? (DISCUSS WITH YOUR NEIGHBOR)

6. I know the organisms are sensitive to the antibiotics but the patient’s not getting better…

6. Why? Is it the antibiotics? Or the patient? Or the anatomy? Or the organisms? (TALK AMONGST YOURSELVES)

UTI Cases A 21-year-old sexually active woman has one day of dysuria but no fever. Exam is normal; urinalysis shows many wbc and bacteria.

SIMPLE CYSTITIS 3 day therapy with trimethoprim-sulfa or 5 days with nitrofurantoin** Culture not mandatory! Quinolones no longer first line because of “collateral damage”**

UTI-2 A 65-year-old man with BPH has 2 days of fever, rigors, vomiting, and severe left flank pain. T 102.8, marked left CVAT, moderately enlarged, nontender prostate. Urine-many WBC, WBC 16, cre 1.0.

GRAM STAIN???? What if I told you urine Gram stain was loaded with Gram positive cocci? Or with thin Gram negative rods without bipolar staining?

COMMUNITY-ACQUIRED PYELONEPHRITIS Admit, IV antibiotics. Must cover enteric GNR’s, especially E. coli. Ceftriaxone fine. Don’t count on quinolones! But if Gram stain has a twist….add Vanco or change to antipseudomonal agent Switch to po when doing well, sensis known. Total duration at least 2 weeks (in men)**

UTI-3 A 50 year old quadriplegic, long term resident of VA SCI service, develops fever, altered mentation, and hypotension. Exam shows no skin lesions or inflammation; CXR clear. Foley urine many wbc, mixed bacteria, pH8

HEALTH-CARE ASSOCIATED UROSEPSIS Supportive care with lots of fluid +/- pressors. Consider ICU. Empiric antibiotics to cover resistant GNR +MRSA. At VA Pseudomonas resistant to zosyn. Change based on results. Rec: Vancomycin, Cefepime, consider Amikacin

UTI-4 Down the hall from case 3, another longterm resident of SCI gets a routine urinalysis from his Foley which shows 800 WBC and mixed bacteria. Afebrile, VSS, no new symptoms. No skin lesions; normal mental status. WBC 6, crea 0.5.

(Do not treat) ASYMPTOMATIC BACTERIURIA

UTI-5 A 79-year old paraplegic man with chronic neurogenic bladder has T 102.1, WBC 12, U/A 2600 WBC and many bacteria. Started on ceftriaxone. Urine grows Klebsiella pneumoniae resistant only to ampicillin. Fever continues…

NOT UTI-5** Exam reveals RUQ tenderness above level of SCI Abd CT reveals edematous GB wall Metronidazole added for anaerobic coverage Cholecystectomy performed: Acute cholecystitis

Soft Tissue Cases

ERYSIPELAS Very likely to be Strep. Good track record of studies supporting not covering MRSA Keflex, Augmentin (or even Penicillin, Amoxicillin) reasonable for outpatient use

Soft Tissue-2 A top high school basketball player scraped against his agent’s Bentley.

CELLULITIS AND/OR SUPPURATIVE INFECTION Focus shifts to include MRSA If pus then DRAIN! For hospitalized patient vancomycin For outpatient TMP-sulfa or doxycycline/minocycline (or clindamycin)** Duration 5 days as good as 10 in uncomplicated**

Soft Tissue-3 After minor trauma to the foot a healthy 30 year old develops fever, shock, & severe LE pain.

NECROTIZING FASCIITIS Representative of complex soft tissue infections with many names When to think of this? Group A strep, or clostridial, or mixed aerobes and anaerobes… Initial rx: Vanco/Cefepime/Flagyl. May substitute clinda for flagyl for Eagle effect.** SURGERY!!!

Soft Tissue-3 A poorly- controlled diabetic w/ neuropathy develops fever and foot drainage.

DIABETIC FOOT INFECTION Mixed aerobes and anaerobes. May include Pseudomonas. Often bone involved Often with poor perfusion Deep cultures to guide therapy. Vancomycin/Cefepime/Flagyl IF GANGRENE OR SEPSIS OR CHRONIC OSTEO-->SURGERY

Pulmonary Cases 60-year old previously healthy smoker with fever, cough with purulent sputum.

COMMUNITY-ACQUIRED PNEUMONIA Pneumococcus, Haemophilus, Moraxella, maybe Legionella. Consider anaerobes, special exposure/risk history TRY TO GET SPUTUM GRAM STAIN AND CULTURE Ceftriaxone/Azithromycin or respiratory quinolone

Pulmonary-2 Alcoholic with 4 weeks of fever, weight loss, fetid sputum, left- sided chest pain.

LUNG ABSCESS Add Klebsiella and anaerobes to usual causes of CAP Ceftriaxone/Flagyl

Pulmonary-3 An SICU patient needs prolonged intubation after abd. surgery. Now fever, inc FiO2, purulent secretions.

VENTILATOR-ASSOCIATED PNEUMONIA Possibility of resistant hospital flora Get deep specimen Gram stain and culture Vancomycin, Cefepime (or Carbapenem if previously on beta lactam), probably Amikacin Consider hospital-acquired Legionella. At VA should probably include Azithromycin.**