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.
ASYMPTOMATIC
BACTERIURIA
(Do not treat)
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 poorlycontrolled
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, leftsided 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.**