1. Infectious Disease I: Antimicrobial Prophylaxis in Surgery
Courses in Therapeutics and Disease State Management

2. Learning Objectives (Slide 1 of 2)
Differentiate between prophylactic, presumptive, and therapeutic antibiotics in the perioperative patient.
Identify patient-specific risk factors for surgical site infections (SSIs).
Identify procedure-specific risk factors for SSIs.
List common pathogens responsible for SSIs.
Explain the importance of timing of antimicrobial prophylaxis for surgery.
Choose an evidence-based prophylactic antimicrobial regimen for specific types of surgeries.

3. Learning Objectives (Slide 2 of 2)
Individualize prophylactic antimicrobial regimens by considering the type of surgery, intrinsic patient risk factors, and knowledge of common pathogenic organisms.
Recommend an alternative prophylactic antimicrobial regimen for patients with life-threatening allergies to first-line therapies.
Identify clinical scenarios where multiple dose regimens of prophylactic antimicrobials are appropriate as compared to single dose regimens.
List nonpharmacological interventions effective at reducing the risk of postoperative SSIs.

4. Required and Recommended Reading
Required Reading
Kanji S. Chapter 101. Antimicrobial Prophylaxis in Surgery. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. eds. Pharmacotherapy: A Pathophysiologic Approach, 9e. New York, NY: McGraw-Hill; 2014.
Recommended Readings
Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Syst Pharm 2013;70:

5. Overview of Surgical Site Infections
Surgical site infections (SSI) are a common cause of nosocomial infections and lead to increased costs and prolonged hospitalization
Prophylactic administration of antibiotics lowers the risk of a surgical site infection
Prevents the contamination of sterile tissues or fluids during surgery
Timing of antibiotics is important to ensure the antibiotic is at a peak concentration at the time of the incision
Infections acquired from surgical procedures and non-surgery related issues are termed nosocomial infections
Presumptive antibiotic therapy is administered to patients where an infection is suspected
Patients with acute appendicitis, compound fractures, or acute cholecystitis are presumed to have an infection until proven otherwise
If no infection is found, the patient will be placed on appropriate prophylactic therapy

6. SSI Categories Incisional: Occurs at the site of surgical incision
Superficial: Skin or subcutaneous tissue
Deep: fascial and muscle layers
Organ/space: Can occur in any anatomic site other than the surgical incision site

7. Surgical Site Infection Risk Factors
Risk of SSI depends on both surgical procedure and patient specific factors
National Research Council has developed a SSI risk classification system

8. National Research Council Wound Classification, Risk of Surgical Site Infection, and Indication for Antibiotics
SSI Rate (%)
Classification
Preoperative Antibiotics
No Preoperative Antibiotics
Criteria
Antibiotics
Clean
5.1
0.8
No acute inflammation or transection of GI, oropharyngeal, genitourinary, biliary, or respiratory tracts; elective case, no technique break
Not indicated unless high-risk procedurea
Clean–contaminated
10.1
1.3
Controlled opening of aforementioned tracts with minimal spillage/minor technique break; clean procedures performed emergently or with major technique breaks
Prophylactic antibiotics indicated
Contaminated
21.9
10.2
Acute, nonpurulent inflammation present; major spillage/technique break during clean–contaminated procedure
Dirty
N/A
Obvious preexisting infection present (abscess, pus, or necrotic tissue present)
Therapeutic antibiotics required
From AccessPharmacy: accesspharmacy.mhmedical.com, Copyright© McGraw-Hill Education. All rights reserved.
Chapter 101. Antimicrobial Prophylaxis in Surgery, Table 101-1
Pharmacotherapy: A Pathophysiologic Approach, 9e, 2014
Joseph T. DiPiro, Robert L. Talbert, Gary C. Yee, Gary R. Matzke, Barbara G. Wells, L. Michael Posey
N/A, not applicable; SSI, surgical site infection. 
aHigh-risk procedures include implantation of prosthetic materials and other procedures where surgical site infection is associated with high morbidity (see the text).
Adapted from references 5 and 11.

9. Surgical Site Infection Risk Factors (cont.)
Patient specific factors must be taken into account when initiation prophylactic antibiotics prior to a surgical procedure
Patient
Operation
Age
Duration of surgical scrub
Nutritional status
Preoperative skin preparation
Diabetes
Preoperative shaving
Smoking
Duration of operation
Obesity
Antimicrobial prophylaxis
Coexisting infections at distal body sites
Operating room ventilation
Colonization with resistant microorganisms
Sterilization of instruments
Altered immune response
Implantation of prosthetic materials
Length of preoperative stay
Surgical drains Surgical technique
Reprinted with permission from Elsevier and the Association for Professionals in Infection Control and Epidemiology.
Original table citation:
Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control 1999;27:97–132.  [PubMed: ] 
Reprinted as Table Patient and Operation Characteristics That May Influence the Risk of Surgical Site Infection Pharmacotherapy: A Pathophysiologic Approach, 9e, 2014
Joseph T. DiPiro, Robert L. Talbert, Gary C. Yee, Gary R. Matzke, Barbara G. Wells, L. Michael Posey

10. Common Bacteria by Surgical Site
Organisms causing SSI originate from two main areas
Endogenously (i.e. normal flora)
Translocation of Staphylococcus aureus on the skin into the sternum during open heart surgery
Exogenously (i.e. contamination during the surgical procedure)
Perforation of the bowel during an appendectomy causing an acute peritonitis
Antimicrobial Resistance
Patients may become colonized with multi drug resistance bacteria
Prolonged inpatient stay prior to surgery
Fomite transmission
Contact with health care providers working in an inpatient setting
Institution antibiograms will aid in the identification of resistance patterns and selection of prophylactic antibiotics

11. Antimicrobial Selection (Slide 1 of 2)
Factors to consider
Classification of surgical procedure and the most common pathogens associated with this procedure
Antimicrobial Specific Factors
Safety and efficacy
Current literature evidence supporting its use
Cost
Patient Specific Factors
Normal flora/ colonization with multi drug resistant pathogens
Allergies
Drug-drug interactions
Institutional susceptibility patterns of nosocomial pathogens

12. Antimicrobial Selection (Slide 2 of 2)
General consideration
Clean surgical procedures such as vascular, orthopedic, neurosurgery, cardiac, etc. utilize cefazolin as the first line prophylactic antibiotic
Cefazolin covers normal skin flora (Staphylococcus sp. and Streptococci sp)
Cefazolin has a narrow spectrum of coverage
Vancomycin is used second line in patients with allergies to β-lactam agents who cannot take cefazolin
Clindamycin is used third line after the cephalosporins and vancomycin, but does provided additional anaerobic coverage
Clean-contaminated surgical procedures such as appendectomy, high risk GI surgery, or whenever the operation will transect a hollow viscous or mucous membrane that may contain resident flora require enteric gram negative bacilli and anaerobic coverage
2nd Generation Cephalosporins with anaerobic coverage are normally the drugs of first choice
Cefoxitin
Cefotetan
Combinations of agents that cover for gram negative bacilli and anaerobes may utilized
Cefazolin plus metronidazole
Vancomycin plus metronidazole
Clindamycin plus aminoglycosides
Metronidazole plus aminoglycosides
Aztreonam plus metronidazole

13. Most Likely Pathogens and Specific Recommendations for Surgical Prophylaxis
Link: Table featuring Most Likely Pathogens and Specific Recommendations for Surgical Prophylaxis

14. Summary
Identify the risk factors for the Surgical Site Infection (SSI)
Surgery type
Most likely pathogens
Select prophylactic antimicrobial therapy
Patient factors
Medication factors
Local resistance
Monitoring signs and symptoms of SSI

15. References
Kanji S. Chapter 101. Antimicrobial Prophylaxis in Surgery. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. eds. Pharmacotherapy: A Pathophysiologic Approach, 9e. New York, NY: McGraw-Hill; Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Syst Pharm 2013;70: