- Prophylaxis refers to the prevention of an infection and can be characterized as primary prophylaxis, secondary prophylaxis, or eradication. These guidelines focus on primary perioperative prophylaxis — the prevention of an initial infection.
- Prophylaxis is recommended in some cases due to the severity of complications of postoperative infection (eg, an infected device that is not easily removable) necessitating precautionary measures even if infection is unlikely.
- Patient-related factors associated with an increased risk of surgical site infection (SSI) include extremes of age, nutritional status, obesity, diabetes mellitus, tobacco use, coexistent remote body site infections, altered immune response, corticosteroid therapy, recent surgical procedure, length of preoperative hospitalization, and colonization with microorganisms.
- Antimicrobial prophylaxis may be justified for any procedure if the patient has an underlying medical condition associated with a high risk of SSI or if the patient is immunocompromised (eg, malnourished, neutropenic, receiving immunosuppressive agents).
- Although antimicrobial prophylaxis plays an important role in reducing the rate of SSIs, other factors may have a strong impact on SSI rates. These include:
- Attention to basic infection control strategies
- The surgeon's experience and technique
- Duration of procedure
- Hospital and operating room environments
- Instrument sterilization
- Preoperative preparation (eg, surgical scrub, skin antisepsis, and appropriate hair removal)
- Perioperative management (temperature and glycemic control)
- The underlying medical condition of the patient
National Healthcare Safety Network (NHSN) Wound Classification Criteria
- Clean: An uninfected operative wound in which no inflammation is encountered and the respiratory, alimentary, genital, or uninfected urinary tracts are not entered.
- In addition, clean wounds are closed primarily and, if necessary, drained with closed drainage.
- Operative incisional wounds that follow nonpenetrating (blunt) trauma should be included in this category if they meet the criteria.
- Clean-contaminated: Operative wounds in which the respiratory, alimentary, genital, or urinary tracts are entered under controlled conditions and without unusual contamination.
- Specifically, operations involving the biliary tract, appendix, vagina, and oropharynx are included in this category, provided no evidence of infection or major break in technique is encountered.
- Contaminated: Open, fresh, accidental wounds.
- In addition, operations with major breaks in sterile technique (eg, open cardiac massage) or gross spillage from the gastrointestinal tract, and
- Incisions in which acute, nonpurulent inflammation is encountered are included in this category.
- Dirty or infected: Includes old traumatic wounds with retained devitalized tissue and those that involve existing clinical infection or perforated viscera.
Note: This definition suggests that the organisms causing postoperative infection were present in the operative field before the operation.
NHSN Criteria for Defining a Surgical Site Infection
- Superficial incisional SSI: occurs within 30 days postoperatively and involves the skin or subcutaneous tissue of the incision and at least one of the following:
- Purulent drainage from the superficial incision.
- Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision.
- At least one of the following signs or symptoms of infection: pain or tenderness, localized swelling, redness, or heat, and the superficial incision is deliberately opened by a surgeon and is culture-positive or not cultured. A culture-negative finding does not meet this criterion.
- Diagnosis of superficial incisional SSI by the surgeon or attending physician.
- Deep incisional SSI: occurs within 30 or 90 daysa after the operative procedure if no implant is left in place or within 1 year if implant is in place and the infection appears to be related to the operative procedure, involves deep soft tissues (eg, fascial and muscle layers) of the incision, and the patient has at least one of the following:
- Purulent drainage from the deep incision but not from the organ/space component of the surgical site.
- A deep incision spontaneously dehisces or is deliberately opened by a surgeon and is culture-positive or not cultured and the patient has at least one of the following signs or symptoms: fever (>38°C), localized pain or tenderness. A culture-negative finding does not meet this criterion.
- An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation, or by histopathologic or radiologic examination.
- Diagnosis of a deep incisional SSI by a surgeon or attending physician.
- Organ/space SSI: involves any part of the body—excluding the skin incision, fascia, or muscle layers—that is opened or manipulated during the operative procedure. Specific sites are assigned to organ/space SSI to further identify the location of the infection (eg, endocarditis, endometritis, mediastinitis, vaginal cuff, and osteomyelitis). Organ/space SSI must meet the following criteria:
- Infection occurs within 30 or 90 daysa after the operative procedure if no implant is in place or within 1 year if implant is in place and the infection appears to be related to the operative procedure,
- Infection involves any part of the body, excluding the skin incision, fascia, or muscle layers, that is opened or manipulated during the operative procedure, and
- The patient has at least one of the following:
- Purulent drainage from a drain that is placed through a stab wound into the organ/space.
- Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/space.
- An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation, or by histopathologic or radiologic examination.
- Diagnosis of an organ/space SSI by a surgeon or attending physician.
Table 1. Surveillance Period for Deep Incisional or Organ/Space SSI Following Selected NHSN Operative Procedure Categoriesa
|30-day Surveillance||Abdominal aortic aneurysm||Heart transplant||Rectum|
|Abdominal hysterectomy||Kidney||Shunt for dialysis|
|Appendix||Kidney transplant||Small bowel|
|Bile duct, liver or pancreas||Laminectomy||Spleen|
|Carotid endarterectomy||Limb amputation||Stomach|
|Cesarean section||Neck||Thyroid and/or parathyroid|
|Exploratory Laparotomy||Ovary||Vaginal hysterectomy|
|Other operative procedures not included in the NHSN categories|
|90-day Surveillance||Breast||Hip prosthesis||Peripheral vascular bypass|
|Craniotomy||Knee prosthesis||Refusion of spine|
|Heart||Open reduction of fracture||Spinal fusion|
|Coronary artery bypass graft with both chest and donor site incisions|
|Coronary artery bypass graft with chest incision only|
Table 2. Specific Sites of an Organ/Space SSIa
|Arterial or venous infection||Mediastinitis|
|Breast abscess or mastitis||Meningitis or ventriculitis|
|Disc space||Myocarditis or pericarditis|
|Ear, mastoid||Oral cavity (mouth, tongue, or gums)|
|Endometritis||Other infections of the male or female reproductive tract|
|Eye, other than conjunctivitis||Other infections of the respiratory tract|
|GI tract||Other infections of the urinary tract|
|Intraabdominal, not specified elsewhere||Spinal abscess without meningitis|
|Intracranial, brain abscess or dura||Upper respiratory tract|
|Joint or bursa||Vaginal cuff|
- Antimicrobial prophylaxis may be beneficial in surgical procedures associated with:
- A high rate of infection (ie, clean-contaminated or contaminated procedures)
- Prosthetic implants
- Severe consequences, even if infection is unlikely
- Certain clean procedures may also warrant prophylaxis.
Note: While prophylactic antimicrobials are not indicated for some clean surgical procedures, available data suggest that the relative risk reduction of SSI from the use of antimicrobial prophylaxis is the same in clean and in higher-risk procedures. The decision to use or not use prophylaxis depends on the cost of treating and the morbidity associated with infection compared with the cost and morbidity associated with using prophylaxis.
- Antimicrobial prophylaxis is justified for most clean-contaminated procedures where the predominant organisms include Gram-negative rods and enterococci.
- The use of antimicrobial agents for dirty procedures or established infections is classified as treatment of presumed infection, not prophylaxis.
- The selection of an appropriate antimicrobial agent for a specific patient should take into account the characteristics of the ideal agent, comparative efficacy of the antimicrobial agent for the procedure, safety profile, and patient medication allergies.
- Choose antimicrobial agents with the narrowest spectrum of activity required for efficacy in preventing infection.
- For patients known to be colonized with methicillin-resistant Staphylococcus aureus (MRSA), it is reasonable to add a single preoperative dose of vancomycin to the recommended agent(s).
- The antimicrobial agent should be started within 60 minutes prior to surgical incision (up to 120 minutes for vancomycin or fluoroquinolones). Vancomycin should NOT be used for routine perioperative prophylaxis and is less effective for methicillin-sensitive S. aureus (MSSA) than cefazolin.
- In theory, using the ideal body weight as the basis for dosing a lipophilic drug (eg, vancomycin) could result in subtherapeutic serum and tissue concentrations, and the use of actual body weight for dosing a hydrophilic drug (eg, an aminoglycoside) could result in excessive serum and tissue concentrations.
Note: Body fat percentage is a more sensitive and precise measurement of SSI risk than body mass index.
Duration of Prophylaxis
- If an agent with a short half-life is used (eg, cefazolin, cefoxitin), it should be readministered if the procedure duration exceeds the recommended redosing interval (from the time of initiation of the preoperative dose [see Table 3]).
- Readministration may also be warranted if prolonged or excessive bleeding occurs, or if there are other factors that may shorten the half-life of the prophylactic agent (eg, extensive burns).
- If antibiotic prophylaxis is continued postoperatively, the duration should be <24 hours regardless of the presence of intravascular catheters or indwelling drains.
Note: Limiting the duration of antimicrobial prophylaxis to a single preoperative dose can reduce the risk of Clostridium difficile disease.
- When given as a single preoperative dose before incision, antibiotic prophylaxis often does not need to be modified for patients with renal or hepatic dysfunction.
- In most cases, the data in pediatric patients are limited and have been extrapolated from adult data. Therefore, all pediatric recommendations are based on expert opinion.
- Fluoroquinolones should NOT be routinely used for surgical prophylaxis in pediatric patients because of the potential for toxicity in this population.
- With few exceptions (eg, aminoglycoside dosages), pediatric dosages should NOT exceed the maximum adult recommended dosages.
Note: Generally, if a dosage calculated on a milligram-per-kilogram basis for children weighing >40 kg exceeds the maximum recommended dosage for adults, adult dosages should be used.
Patients with Prosthetic Implants
- For patients with existing prosthetic implants who undergo an invasive procedure, there is no evidence that antimicrobial prophylaxis prevents infections of the implant. However, updated guidelines from the American Heart Association suggest that prophylaxis may be justified in a limited subset of patients for the prevention of endocarditis.
- S. aureus (MSSA or MRSA) colonizes a significant portion of surgical patients and is a leading cause of all SSIs in the United States.
S. aureus colonization is associated with a significantly increased risk of SSI.
- Endogenous S. aureus carriage in surgical patients requires a specialized approach for eradication of these pathogens.
Notes: Preoperative surveillance cultures can be used to identify colonized patients in the preoperative period.
Anterior nasal swab cultures are most commonly used, but evidence suggests that additional site screening (pharynx, groin, wounds, rectal) can increase detection.
- The use of decolonization therapy (eg, mupirocin) may be employed as an adjunctive measure to prevent S. aureus SSI with surveillance of susceptibility to mupirocin of S. aureus isolated from SSIs.
Notes: While universal use of mupirocin is discouraged, data demonstrate a 45% reduction in S. aureus SSI with the use of preoperative mupirocin among patients known to be colonized with S. aureus undergoing cardiac procedures.
Mupirocin should be given intranasally to all patients with documented colonization with S. aureus undergoing orthopedic spinal procedures with or without instrumentation.
- The safety and efficacy of topical antibiotics have not been clearly established, and therefore routine use of this route cannot be recommended.
Existing Antibiotic Treatment
- If the agent(s) used therapeutically is (are) appropriate for surgical prophylaxis, administering an extra dose within 60 minutes prior to incision is sufficient. Otherwise, use the antibiotic prophylaxis recommended for the planned procedure.
- Because the predominant organisms in SSIs after clean procedures are Gram positive, the use of vancomycin may be appropriate for a patient with a life-threatening allergy to β-lactam antibiotics.
Table 3. Recommended Doses and Redosing Intervals for Commonly Used Antimicrobials for Surgical Prophylaxis
|Antimicrobial||Recommendations||Adult Half-Life in Normal Renal Function (hrs)d|
|Adult Dosea||Pediatric Doseb||Redosing Intervalc,d|
(ampicillin 2 g/
sulbactam 1 g)
of the ampicillin
|2 g||50 mg/kg||2 hrs||1-1.9|
|2 g||30 mg/kg||4 hrs||1.3-2.4|
3 g for
|30 mg/kg||4 hrs||1.2-2.2|
|1.5 g||50 mg/kg||4 hrs||1-2|
|1 ge||50 mg/kg||3 hrs||0.9-1.7|
|2 g||40 mg/kg||2 hrs||0.7-1.1|
|2 g||40 mg/kg||6 hrs||2.8-4.6|
|2 gi||50-75 mg/kg||NA||5.4-10.9|
|400 mg||10 mg/kg||NA||3-7|
|900 mg||10 mg/kg||6 hrs||2-4|
|1 g||15 mg/kg||NA||3-5|
based on dosing weight (single dose)
based on dosing weight
|500 mg||10 mg/kg||NA||6-8|
|500 mg||15 mg/kg:|
<1200 g should receive a single
7.5 mg/kg dose
|400 mg||10 mg/kg||NA||8-15|
|3.375 g||Infants 2-9 mos of age: 80 mg/kg|
of the piperacillin component
Children >9 mos of age and ≤40 kg:
of the piperacillin component
|15 mg/kg||15 mg/kg||NA||4-8|
|Oral Antibiotics for Colorectal Surgery Prophylaxish|
|1 g||20 mg/kg||NA||NA|
|1 g||15 mg/kg||NA||NA|
|1 g||15 mg/kg||NA||NA|
|Apply to nares bid||NA||NA|
b The maximum pediatric dose should NOT exceed the usual adult dose.
c From initiation of the preoperative dose.
d For antimicrobials with a short half-life (eg, cefazolin, cefoxitin) used before long procedures, redosing in the operating room is recommended at an interval of approximately two times the half-life of the agent in patients with normal renal function. Recommended redosing intervals marked as “not applicable” (NA) are based on typical case length; for unusually long procedures, redosing may be needed.
e Although FDA-approved package insert labeling indicates 1 g, experts recommend 2 g for obese patients.
f While fluoroquinolones have been associated with an increased risk of tendinitis/tendon rupture in all ages, use of these agents for single-dose prophylaxis is generally safe.
g In general, gentamicin for surgical antibiotic prophylaxis should be limited to a single dose given preoperatively. Dosing is based on the patient’s actual body weight. If the patient’s actual weight is more than 20% above ideal body weight (IBW), the dosing weight (DW) can be determined as follows: DW = IBW 0.4 (actual weight − IBW).
h ALWAYS neomycin with EITHER metronidazole OR erythromycin base used in conjunction with a mechanical bowel preparation and given as three doses over approximately 10 hours the afternoon and evening before the operation and after the mechanical bowel prep.
i 3% absorbed under normal gastrointestinal conditions.
j When used as a single dose in combination with metronidazole or erythromycin base for colorectal procedures.
Table 4. Antimicrobial Recommendations for Surgical Prophylaxis Stratified by Type of Procedure
|Type of Procedure||Recommended Agentsa,b||Strength of Evidence||Alternative in β-Lactam Allergy|
|Appendectomy for uncomplicated appendicitis|
aminoglycosidec or aztreonam or
|A||Clindamycin or vancomycin|
or aztreonam or fluoroquinoloned-f
|A||Clindamycin or vancomycin|
aztreonam or fluoroquinoloned-f
|Coronary artery bypass||Cefazolin|
|Cardiac device insertion procedures (eg, pacemaker implantation)||Cefazolin|
|Ventricular assist devices||Cefazolin|
or aztreonam or
|Procedures involving entry into lumen of gastrointestinal tract, or gastric bypass procedures||Cefazolin||A||Clindamycin or vancomycin|
or aztreonam or
|Procedures without entry into the gastrointestinal tract (antireflux, highly selective vagotomy) for high risk patients||Cefazolin||Clindamycin or|
|Head and Neck|
|With placement of prosthesism||Cefazolin|
|Clean-contaminated cancer surgery||Cefazolin|
|Other clean-contaminated procedures with the exception of tonsillectomy and functional endoscopic sinus procedures||Cefazolin|
|Hernia Repair Procedures|
|Elective craniotomy and cerebrospinal fluid-shunting procedures||Cefazolin||A||Clindamycini|
|Implantation of intrathecal pumps||Cefazolin||C||Clindamycini|
|Hysterectomy (vaginal or abdominal)||Cefazolin||A||Clindamycin or|
or aztreonam or
|Ophthalmic (Addition of cefazolin 100 mg by subconjunctival injection or intracameral cefazolin 1-2.5 mg or cefuroxime 1 mg at the end of the procedure is optional.)|
|Clean procedures involving hand, knee, or foot, not involving implantation of foreign materials||None||C||None|
|Spinal procedures with and without instrumentation||Cefazolin||A||Clindamycini|
|Hip fracture repair||Cefazolin||A||Clindamycini|
|Implantation of internal fixation deviceso||Cefazolin||C||Clindamycini|
|Total joint replacement||Cefazolin||A||Clindamycini|
|Clean with risk factors or clean-contaminated||Cefazolin|
or aztreonam or
|Noncardiac procedures, including lobectomy, pneumonectomy, lung resection, and thoracotomy||Cefazolin|
|Video-assisted thoracoscopic surgery||Cefazolin|
|Heartp||Cefazolin||A (based on cardiac procedures)||Clindamycini|
|Lung and heart–lungq,r||Cefazolin||A (based on cardiac procedures)||Clindamycini|
or aztreonam or
|Pancreas and pancreas–kidney||Cefazolin||A||Clindamycin or|
or aztreonam or
or aztreonam or
|Lower tract instrumentation with risk factors for infectiont||Fluoroquinoloned-f||A||Aminoglycosidec|
|Clean without entry into urinary tractu||Cefazolin||A||Clindamycini|
|Involving implanted prosthesis||Cefazolin|
aminoglycoside or aztreonam
|Clean with entry into urinary tractu||Cefazolin||A||Fluoroquinoloned-f|
a The antimicrobial agent should be started within 60 minutes prior to surgical incision (120 minutes for vancomycin or fluoroquinolones). While single-dose prophylaxis is usually sufficient, the duration of prophylaxis for all procedures should be <24 hours. If an agent with a short half-life is used (eg, cefazolin, cefoxitin), it should be readministered if the procedure duration exceeds the recommended redosing interval (from the time of initiation of the preoperative dose [see Table 2]). Readministration may also be warranted if prolonged or excessive bleeding occurs, or if there are other factors that may shorten the half-life of the prophylactic agent (eg, extensive burns). Readministration may not be warranted in patients in whom the half-life of the agent may be prolonged (eg, patients with renal insufficiency or failure).
b For patients known to be colonized with methicillin-resistant S. aureus, it is reasonable to add a single preoperative dose of vancomycin to the recommended agent(s).
d Due to increasing resistance of E. coli to fluoroquinolones and ampicillin-sulbactam, local population susceptibility profiles should be reviewed prior to use.
f Fluoroquinolones are associated with an increased risk of tendonitis and tendon rupture in all ages. However, this risk would be expected to be quite small with single-dose antibiotic prophylaxis. Although the use of fluoroquinolones may be necessary for surgical antibiotic prophylaxis in some children, they are not drugs of first choice in the pediatric population due to an increased incidence of adverse events as compared with controls in some clinical trials.
g Ceftriaxone use should be limited to patients requiring antimicrobial treatment for acute cholecystitis or acute biliary tract infections which may not be determined prior to incision, not patients undergoing cholecystectomy for noninfected biliary conditions, including biliary colic or dyskinesia without infection.
h Factors that indicate a high risk of infectious complications in laparoscopic cholecystectomy include emergency procedures, diabetes, long procedure duration, intraoperative gallbladder rupture, age >70 years, conversion from laparoscopic to open cholecystectomy, higher American Society of Anethesiologists (ASA) classification, episode of colic within 30 days prior to procedure, reintervention in <1 month for noninfectious complication, acute cholecystitis, bile spillage, jaundice, pregnancy, nonfunctioning gallbladder, immunosuppression, and insertion of prosthetic device. Because a number of these risk factors are not possible to determine prior to surgical intervention, it may be reasonable to give a single dose of antimicrobial prophylaxis to all patients undergoing laparoscopic cholecystectomy.
i For procedures in which pathogens other than staphylococci and streptococci are likely, an additional agent with activity against those pathogens could be considered. For example, if there are surveillance data showing that gram-negative organisms are a cause of surgical site infections for the procedure, practitioners should consider combining clindamycin or vancomycin with another agent (cefazolin if the patient is not β-lactam allergic; aztreonam, gentamicin, or single-dose fluoroquinolone if the patient is β-lactam allergic).
j For most patients, a mechanical bowel preparation combined with oral neomycin sulfate plus oral erythromycin base, or with oral neomycin sulfate plus oral metronidazole should be given in addition to intravenous prophylaxis. The oral antibiotics should be given as three doses over approximately 10 hours the afternoon and evening before the operation and after the mechanical bowel prep.
k Where there is increasing resistance to 1st and 2nd generation cephalosporins among gram negative isolates from SSIs, a single dose of ceftriaxone plus metronidazole may be preferred over routine use of carbapenems.
l Prophylaxis should be considered for patients at highest risk for postoperative gastroduodenal infections, such as those with increased gastric pH (eg, those receiving histamine H2-receptor antagonists or proton-pump inhibitors), gastroduodenal perforation, decreased gastric motility, gastric outlet obstruction, gastric bleeding, morbid obesity, or cancer. Antimicrobial prophylaxis may not be needed when the lumen of the intestinal tract is not entered.
m Prostheses excludes tympanostomy tubes.
n The necessity of continuing topical antimicrobials postoperatively has not been established.
o Procedures involving internal fixation devices (eg, nails, screws, plates, wires).
p These guidelines reflect recommendations for perioperative antibiotic prophylaxis to prevent surgical site infections and do not provide recommendations for prevention of opportunistic infections in immunosuppressed transplantation patients (eg, for antifungal or antiviral medications).
q Patients who have left ventricular assist devices as a bridge and who are chronically infected might also benefit from coverage of the infecting microorganism.
r The prophylactic regimen may need to be modified to provide coverage against any potential pathogens, including gram-negative (eg, P. aeruginosa) or fungal organisms, isolated from the donor lung or the recipient before transplantation. Patients undergoing lung transplantation with negative pretransplantation cultures should receive antimicrobial prophylaxis as appropriate for other types of cardiothoracic surgeries. Patients undergoing lung transplantation for cystic fibrosis should receive 7–14 days of treatment with antimicrobials selected according to pretransplantation culture and susceptibility results. This treatment may include additional antibacterial agents or antifungal agents.
s The prophylactic regimen may need to be modified to provide coverage against any potential pathogens, including vancomycin-resistant enterococci, isolated from the recipient before transplantation.
t Includes transrectal prostate biopsy.
u The addition of a single dose of an aminoglycoside may be recommended for placement of prosthetic material (eg, penile prosthesis).
v Prophylaxis is not routinely indicated for brachiocephalic procedures. Although there are no data in support, patients undergoing brachiocephalic procedures involving vascular prostheses or patch implantation (eg, carotid endarterectomy) may benefit from prophylaxis.