Transcript What comes after Ancef? A guide to antimicrobial prophylaxis in the

What comes after Ancef?
A guide to antimicrobial prophylaxis in the
surgical patient
Course Objectives
1. Identify commonly used antibiotics in the surgical setting
2. Describe the mechanism of action of commonly used
antibiotics
3. Identify common surgical pathogens
4. Discuss current guidelines for antimicrobial prophylaxis
during surgery
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Before we figure out what weapons we need to use
we first need to know who the enemies are
Gram staining
By Graevemoore at English Wikipedia, CC BY-SA 3.0
https://commons.wikimedia.org/w/index.php?curid=8477969
Meet Staph Aureus
› Aerobic gram positive cocci
› Is the primary cause of the
majority SSI (up to 30 %)
› Staph aureus is ubiquitous. Part
of the natural flora of the skin
and mucous membranes.
› Colonization occurs in about 1 in
4 patients and increases the risk
of SSI by up to 14 fold
› Harmless until it penetrates
deeper tissues
Enzymes secreted by staph A.
› Coagulase: Converts fibrinogen into fibrin to form clots.
Prevents phagocytosis.
› Staphylokinase: dissolves fibrin, spreads the bacteria
› Deoxyrobonuclease: breaks down DNA
› Beta-lactamase – degrades the beta lactam ring and causes
drug resistance.
Other gram positive organisms
› Staph epidermis known for its bio slime and occurs in sternal
wounds and prosthesis
› Streptococcus, commonly found in mouth throat skin and
intestine are commonly found SSI bacteria and can cause
hemolysis. Common subtypes include Streptococcus pyogenes
and Enterococcus.
› Streptococcus pyogenes: Group A streptococcus is responsible
for type II necrotizing fasciitis
› Enterococcus: present in the adult GI tract and account for a
large amount of clean contaminated SSI
› All of these bacteria can be either aerobic or anaerobic
Anaerobic Gram positive bacilli
› Members of the clostridium species
› Cause tetanus and botulism, but are not common in surgical
site infection
› Clostridium perfringens causes the surgical site infection
known as “gas gangrene”
› C difficile occurs when the normal flora of the intestine are
eliminated by prolonged antibiotic therapy- may lead to toxic
megacolon
Gram positive cocci account for nearly 50% of all surgical site infections
Gram negative bacilli
› Primarily found in the intestines
› Account for about 20 % Of
surgical site infections
› . Enterobacter spp,
› Escherichia coli (E coli )
› Klebsiella pneumoniae
Anaerobic gram negative organisms:
BACTEROIDES FRAGILIS
› Most common anaerobe in
intraabdominal infections
› Has the tendency to form
capsules and are notorious for
the formation of appendicitic
abscess
Now that we know what we are fighting, let’s see what tools we have to use
Beta Lactam Antibiotics
› Are the most commonly prescribed
antibiotic for surgical site infection
› They work by inactivating a set of
enzymes that are necessary for cell
wall synthesis
› These enzymes are called penicillin
binding proteins (PBP) and different
bacteria have anywhere between 4
and 8 of them
› Each PBP has a different function
depending on the bacteria and each
of the beta lactam drugs impact cell
wall synthesis diffently
› Cover a broad spectrum of microorganisms and we will look at them
more closely later in the lecture
› Anaphylaxis is the primary concern
Beta Lactam Antibiotics
Penicillins
Narrow spectrum
Not commonly
used
perioperatively
Cephalosporins
Broad Spectrum
Ampicillin
1st Generation
Cefazolin
2nd Generation
3rd Generation
Cefuroxime
Cefotaxime
Cefoxitin
Ceftriaxone
Cefotetan
4th and 5th
Generation
Not commonly
used
perioperatively
Carbapenems
Monobactams
Ertapenem
Aztreonam
Beta lactamase
inhibitors
Sulbactam
Tazocactam
Selection of antimicrobial agent
Appropriate
spectrum of activity
Inexpensive
Cefazolin
Desirable side
effect profile
Appropriate
duration of action
Beta lactam allergy
› Patients who have a penicillin
allergy generally react to either the
beta lactam ring or the R group
side chain
› 2% of patients who are skin test
positive for penicillin have a cross
sensitivity to cephalosporins
› There is a 1% chance of cross
sensitivity with carbapenems
› There is no evidence of cross
sensitivity with aztreonam
› All of these drugs are safe to use if
the allergy is not IgE mediated
Quinolones
› Levofloxacin
› Ciprofloxacin
› Bind to the enzymes that are involved with DNA synthesis
leading to cell death
› Largest degree of activity is against gram negative bacilli and
gram negative rods. Limited activity against staph and
enterococcus
› Adverse effects include C-Diff colitis, peripheral neuropathy
and tendon rupture
Aminoglycosides
› Gentamycin
› Works by inhibiting translocation of DNA to RNA
› Activity primarily against aerobic gram negative bacteria
› Nephrotoxic
› Ototoxic
› Neuromuscular blockade and is contraindicated in myasthenia
gravis
Clindamycin (lincosamide antibiotic)
› Inhibits bacterial protein synthesis, and is bacteriostatic ( as
opposed to bactericidal)
› Activity against MRSA, Gram positive bacteria and Anaerobes
› Adverse reactions: C-diff colitis
Metronidazole
› Mainstay of treatment for obligate anaerobic bacteria (C-Diff)
› Its low molecular weight allows it to pass easily into the cell
and destabilize the DNA helix
› Can turn urine into a red brown color
› Can cause flushing and tachycardia and nausea on vomiting if
given to patients who have had alcohol
Vancomycin
› A glycopeptide antibiotic
› Spectrum of activity include gram positive bacteria including MRSA
› Routine prophylaxis with vancomycin is not recommended for any
surgical procedure in an effort to control vancomycin resistance
› Should be reserved for patients that are MRSA positive of
institution that are experiencing clusters of MRSA.
› Adverse reaction includes red man syndrome
› Ototoxic
› nephrotoxic
Now lets put it all together
Recommendations
Orthopedic procedures
› Procedures with implantation,
the recommendation is
cefazolin which covers gram
positive staph and e-coli
› 2nd generation cephalosporin
are equally as effective in
preventing surgical site
infection, but are more costly,
and have a broader spectrum
which may contribute to
resistance and C-Diff
› Vancomycin and clindamycin
are alternatives for patients
with a beta lactam allergy
Orthopedic procedures not involving implantation
› Arthroscopy of the knee hand and foot have low infection
rates
› These guidelines do not recommend antibiotics
Cardiac procedures
› Recommendation: cefazolin or a 2nd
generation cephalosporin
(cefuroxime)
› Vancomycin or clindamycin is
acceptable in a beta lactam allergy
Thoracic Procedures
› Thoracic procedures can also carry the
risk of pneumonia. Some studies
indicate that ampicillin-sulbactam is
more effective than cephalosporins
› The recommendation is cefazolin or
ampicillin-sulbactam
Urologic procedures
› The primary concern for urologic
procedures entering the urinary tract is
bacteriuria cased by E. Coli and other
gram negative bacilli
› The recommendation is
Fluoroquinolones.
› Procedures that enter the urinary tract
through the skin will require cefazolin
plus a strong gram negative like
gentamicin or a fluoroquinolone
Surgeries of the bowel
› The natural flora of the
bowel changes as you travel
down the intestine
› Patients with a small bowel
obstruction or appendicitis
get treated the same way as
patients undergoing bowel
surgery
Biliary Tract
• E. Coli (G-)
• Klebiella (G-)
• Enterococci (G+)
Small Intestine
• E. Coli (G-)
• Klebiella (G-)
• Enterococci (G+)
Colon
• B fragilis (anaerobe)
• E coli
Surgeries of the Gastrointestinal tract
› Biliary tract recommendations:
› Cefazolin. Studies show that there is no difference between
1st 2nd and 3rd generations cephalosporins
› Small Bowel recommendations:
› Cefazolin Unless there is small bowel obstruction then the
recommendation is for a 2nd generation cephalosporin or
cefazolin and metronidazole.
› Colorectal recommendations (including Appendectomy)
› 2nd generation cephalosporins or cefazolin and
metronidazole
Head and Neck procedures
› Clean head and neck procedures, as well as tonsillectomy and
endoscopic sinus surgeries have a very low rate of infection,
and do not require antibiotic prophylaxis
› Clean-contaminated, commonly head in neck cancer, are very
complex do to the flora of the mouth,
› Recommendations for clean contaminated procedures
› 1st or 2nd generation cephalosporin with the addition of
metronidazole
› For patients with a beta lactam allergy, clindamycin plus
gentamycin covers the gamut.
Reference
1.
CDC. New York activities to prevent HAIs. http://www.cdc.gov/HAI/stateplans/state-hai-plans/ny.html. Accessed
September 24, 2016.
2.
Qadan M, Cheadle WG. Common microbial Pathogens in surgical practice. Surgical Clinics of North America.
2009;89(2):295–310. doi:10.1016/j.suc.2008.09.002.
3.
Calderwood, SB. Beta-lactam antibiotics: Mechanisms of action and resistance and adverse effects. In: Up to
Date, Hooper, DC. (Ed), UpToDate.Waltham, MA. (Accessed on August 28, 2016.)
4.
Solenski, R, SB. Penicillin-allergic patients: Use of cephalosporins, carbapenems, and monobactams. In: Up to
Date, Adkinsen, NF. (Ed), UpToDate.Waltham, MA. (Accessed on Sept 02, 2016.)
5.
Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery.
American Journal of Health-System Pharmacy. 2013;70(3):195–283. doi:10.2146/ajhp120568.
6.
Hooper DC. Fluoroquinolones . In: Up to Date, Calderwood SB. (Ed), UpToDate.Waltham, MA. (Accessed on Sept
01, 2016.)
7.
Johnson M. Clindamycin: An overview In: Up to Date,Hooper DC. (Ed), UpToDate.Waltham, MA. (Accessed on
August 21, 2016.)
8.
Johnson M. Metronidazole: An overview In: Up to Date,Hooper DC. (Ed), UpToDate.Waltham, MA. (Accessed on
August 21, 2016.)
9.
Drew, R. Clindamycin: Vancomycin dosing and serum concentration monitoring in adults ,Hooper DC. (Ed),
UpToDate.Waltham, MA. (Accessed on August 24, 2016.)