INTRODUCTION — The rate of surgical site infections (SSIs) is low for most surgical procedures. Because of the relatively large surgical volume in many community hospitals, SSIs are the most common health care-associated infection [1]. The United States Centers for Disease Control and Prevention has developed criteria that define SSI as infection related to an operative procedure that occurs at or near the surgical incision within 30 days of the procedure or within 90 days if prosthetic material is implanted at surgery [2]. SSIs are often localized to the incision site but can also extend into deeper adjacent structures.
Gastrointestinal procedures are among the highest risk procedures for SSI due to the presence of intraluminal bacteria. According to data published by the National Healthcare Safety Network, rates of SSI following bile duct, liver, or pancreatic surgery are as high as 10 per 100 procedures. Rates of SSI following colon surgery are approximately 5 per 100 procedures, and rates of SSI following gallbladder surgery are 0.7 per 100 procedures [3].
Issues related to prevention of SSI following gastrointestinal surgery will be reviewed here. Issues related to the prevention of SSI following gastrointestinal endoscopic procedures are discussed separately. (See "Antibiotic prophylaxis for gastrointestinal endoscopic procedures" and "Preventing infection transmitted by gastrointestinal endoscopy" and "Infectious adverse events related to endoscopic retrograde cholangiopancreatography (ERCP)".)
Issues related to epidemiology of SSI and general principles of SSI risk and prevention such as maintaining normothermia, glucose control, and supplemental oxygen are discussed further separately. (See "Risk factors for impaired wound healing and wound complications" and "Antimicrobial prophylaxis for prevention of surgical site infection in adults" and "Overview of control measures for prevention of surgical site infection in adults".)
Specific preventative measures related to surgical techniques including the use of wound protectors in gastrointestinal surgery are also discussed separately. (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Surgical technique' and "Overview of the evaluation and management of surgical site infection", section on 'Measures to reduce risk'.)
ANTIMICROBIAL PROPHYLAXIS — There are two key components of antimicrobial prophylaxis for prevention of SSI following gastrointestinal procedures: antibiotic selection and timing of administration (to optimize tissue concentration at the time of surgery). The choice of agents depends on the type of procedure, as discussed in the following sections (table 1). Timing of administration is discussed separately (see "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Timing'). Additional antimicrobial prophylaxis should be administered immediately prior to surgery even in patients who are receiving parenteral therapy as treatment for a known or suspected appendicitis or for an infection such as diverticulitis or a bowel perforation in order to assure that therapeutic antibiotic levels are present during the surgical procedure.
Gastroduodenal procedures — Antimicrobial prophylaxis with cefazolin is warranted for patients undergoing clean-contaminated procedures during which the lumen of the intestinal tract is entered [4,5]. These include ulcer resection, carcinoma resection, perforation repair, gastric outlet stricture repair, percutaneous endoscopic gastrostomy (PEG) insertion, pancreaticoduodenectomy (Whipple procedure), and bariatric surgical procedures. (See "Partial gastrectomy and gastrointestinal reconstruction" and "Total gastrectomy and gastrointestinal reconstruction" and "Gastrostomy tubes: Placement and routine care".)
For patients undergoing clean procedures such as selective vagotomy and antireflux procedures, antimicrobial prophylaxis is warranted only for patients at increased risk for SSI in the setting of such procedures. Risk factors include [6-9]:
●Diminished gastric acidity (eg, patients on acid-suppression therapy)
●Gastroduodenal perforation
●Diminished gastrointestinal motility
●Esophageal obstruction
●Gastric outlet obstruction
●Gastric bleeding
●Class 2 obesity
●American Society of Anesthesiologists classification ≥3 (table 2)
●Malignancy
SSI rates in patients not receiving antimicrobial prophylaxis are 6 percent after vagotomy and drainage, 13 percent after gastric ulcer procedures, 7 to 17 percent after gastric cancer procedures [10,11], 8 percent for Whipple procedure [12], and 24 to 26 percent after PEG insertion [4].
The most common organisms cultured from SSIs after gastroduodenal procedures are coliforms (Escherichia coli, Proteus species, Klebsiella species), staphylococci, streptococci, enterococci, and occasionally Bacteroides species.
Appropriate antibiotics are summarized in the table (table 1).
Biliary tract procedures — Antimicrobial prophylaxis with cefazolin is warranted in patients undergoing open biliary tract procedures. Alternative agents include other cephalosporins (cefotetan, cefoxitin, ceftriaxone) or ampicillin-sulbactam.
For low-risk patients undergoing elective laparoscopic cholecystectomy, we agree with guidelines that no antimicrobial prophylaxis is necessary [8,13-16]. However, some surgeons and UpToDate surgical contributors give antimicrobial prophylaxis to all patients undergoing cholecystectomy. More detailed discussion of this issue is found elsewhere (See "Laparoscopic cholecystectomy", section on 'Antibiotics'.)
Routine antimicrobial prophylaxis is not warranted for patients undergoing endoscopic retrograde cholangiopancreatography [17], even in patients thought to have biliary tract stones or distal bile duct stricture [18]. Antimicrobial prophylaxis is warranted in patients with biliary obstructionor risk factors for incomplete drainage, as discussed separately [19]. (See "Antibiotic prophylaxis for gastrointestinal endoscopic procedures", section on 'Endoscopic retrograde cholangiopancreatography (ERCP)'.)
Organisms most commonly associated with infection after biliary tract procedures include E. coli, Klebsiella species, and enterococci; less frequently, other gram-negatives, streptococci, and staphylococci are isolated. Anaerobes are occasionally reported, most commonly Clostridium species. Increasing antimicrobial resistance has been observed among pathogens causing intraabdominal infections, with up to 40 percent of E. coli resistant to ampicillin-sulbactam and fluoroquinolones [20].
Appropriate antibiotics are summarized in the table (table 1).
Pancreatic procedures — In general, guidelines for biliary tract surgery may also be applied to pancreatic procedures (table 1). The risk of SSI is increased in the setting of endoscopic or percutaneous biliary or pancreatic drainage procedures done prior to pancreatic surgery [21]. Therefore, antimicrobial prophylaxis prior to the pancreatic procedure should be expanded to cover microorganisms recovered from biliary drains. (See "Surgical resection of lesions of the body and tail of the pancreas".)
A pragmatic open-label randomized controlled trial compared the use of piperacillin-tazobactam for antimicrobial prophylaxis to cefoxitin in 778 patients undergoing pancreatoduodenectomy [22]. This trial was terminated at an interim analysis due to a decrease in SSI with piperacillin-tazobactam (19.8 versus 32.8 percent; P<0.001). While these data suggest the use of piperacillin-tazobactam leads to improved outcomes, these findings have limitations and must be interpreted in context. Patients in this trial had a high rate of SSI in both arms that may limit generalizability. In addition, the comparator arm used a second-line agent. Finally, the impact of expanded coverage with piperacillin-tazobactam on antimicrobial resistance and the microbiome is unknown.
Appendectomy procedures — Uncomplicated appendicitis consists of an acutely inflamed appendix. Complicated appendicitis consists of perforated or gangrenous appendicitis, including peritonitis or abscess formation. (See "Management of acute appendicitis in adults".)
Antimicrobial prophylaxis is warranted in the setting of uncomplicated appendicitis [23,24]; a reasonable regimen is a first-generation cephalosporin (cefazolin) plus metronidazole. Patients with complicated appendicitis should receive preoperative antibiotics and continue therapy for at least five days [6].
Mean SSI rates for appendectomy reported by the National Healthcare Safety Network (NHSN) in 2009 were 1.2 percent for risk categories 0 and 1 and 3.5 percent for risk categories 2 and 3 [3]. Laparoscopic appendectomy has been reported to produce lower rates of incisional SSIs than open appendectomy, although the rate of organ/space SSIs (ie, intraabdominal abscesses) appears to be increased with laparoscopic appendectomy [15,25].
The most common organisms isolated from SSIs after appendectomy are anaerobic and aerobic gram-negative enteric organisms. Bacteroides fragilis is the most commonly cultured anaerobe, and E. coli is the most frequent aerobe. Aerobic and anaerobic streptococci, Staphylococcus species, and Enterococcus species have also been reported.
Appropriate antibiotics are summarized in the table (table 1).
Small intestine procedures — For small bowel surgery without obstruction, antimicrobial prophylaxis with cefazolin is warranted. For small bowel surgery in the setting of obstruction, additional coverage for anaerobic pathogens is warranted (table 1).
Small intestine procedures include incision or resection of the small intestine, including enterectomy with or without intestinal anastomosis or enterostomy, intestinal bypass, and strictureplasty; it does not include small-to-large bowel anastomosis. Mean SSI rates for small bowel procedures reported by the NHSN in 2009 were 3.4 percent for NHSN risk category 0 and 6.7 percent for NHSN risk categories 1, 2, and 3 [3].
Data on antimicrobial prophylaxis for small bowel surgery are limited; the role of antimicrobial prophylaxis is inferred from its efficacy in other clean-contaminated procedures. Microorganisms isolated from SSIs after small bowel surgery include gram-negative enteric organisms (aerobic and anaerobic) and gram-positive species such as streptococci, staphylococci, and enterococci [26].
Hernia repair procedures — Antimicrobial prophylaxis with cefazolin is warranted for patients undergoing hernioplasty (prosthetic mesh repair of hernia) or herniorrhaphy (suture repair of hernia) (table 1) [27-29]. The most common organisms isolated from SSI after hernia repair are aerobic gram-positive organisms and aerobic streptococci, staphylococci, and enterococci [30].
Issues related to antimicrobial prophylaxis prior to hernia repair are discussed separately. (See "Overview of treatment for inguinal and femoral hernia in adults", section on 'Antibiotic prophylaxis'.)
Issues related to mesh graft infection following hernia repair are discussed separately. (See "Wound infection following repair of abdominal wall hernia" and "Complications of inguinal and femoral hernia repair", section on 'Deep incisional/mesh infection'.)
Colorectal procedures — Intravenous antimicrobial prophylaxis for colorectal procedures is warranted with cefazolin plus metronidazole or a second-generation cephalosporin (cefoxitin or cefotetan) [31]. We prefer cefazolin plus metronidazole due to increasing E. coli resistance to second-generation cephalosporins. Dosing is summarized in the table (table 1). Intravenous antimicrobial prophylaxis significantly reduces SSI rates and mortality rates; one pooled analysis of 26 trials noted SSI rates of 4.5 versus 11.2 for treatment and control groups, respectively [32].
Ideally, antimicrobial prophylaxis provides appropriate coverage without being overly broad. For example, the combination of cefazolin and metronidazole provides appropriate coverage for both aerobic gram-negative enteric bacilli and anaerobes [8]. Several other agents can provide adequate surgical prophylaxis, but provide no advantage over less broad options and potentially lead to a higher risk of adverse events, such postoperative Clostridioides difficile infection [33]. For example, the combination of a second- or third-generation cephalosporin plus metronidazole is no more effective than combination of cefazolin and metronidazole [34]. Routine use of third- or fourth-generation cephalosporins for prophylaxis can also lead to emergence of resistant organisms [35]. Carbapenems are effective for surgical prophylaxis; however, their use may increase the risk of subsequent colonization or infection from resistant organisms such as carbapenem-resistant Enterobacteriaceae [36,37].
The approach to selecting antimicrobial surgical prophylaxis for patients known to be colonized with drug-resistant pathogens must be individualized. In a prospective cohort study of 3600 patients undergoing elective colorectal surgery who had received standard antibiotic prophylaxis with a cephalosporin and metronidazole, a greater proportion of patients with than without fecal carriage of extended-spectrum beta-lactamase-producing Enterobacteriaceae had SSI caused by the resistant organism (7.2 versus 1.6 percent, odds ratio 4.23, 95% CI 1.70-10.56) [38].
The infecting organisms in colorectal procedures are derived from the bowel lumen, where there are high concentrations of organisms. B. fragilis and E. coli are the most frequently isolated pathogens from infected surgical sites after colon procedures. B. fragilis and other obligate anaerobes are the most frequently isolated organisms from the bowel, with concentrations 1000 to 10,000 times higher than those of aerobes [39].
The benefit of topical antibiotics and other antiseptics for prevention of SSI is uncertain. One meta-analysis of randomized studies examining the efficacy of topical application of both antibiotics (such as gentamicin sponges) and antiseptics (such as chlorhexidine) applied to open incisions or immediately after wound closure to reduce the risk of SSI following colorectal procedures concluded that some agents showed benefit in reducing the risk of a SSI, but the evidence of benefit was inconsistent and of low to moderate quality [40].
Issues related to bowel preparation and standardized protocols for colorectal surgery are discussed separately. (See "Overview of colon resection", section on 'Bowel preparation' and "Enhanced recovery after colorectal surgery".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Prevention of surgical site infections in adults".)
SUMMARY AND RECOMMENDATIONS
●Epidemiology – Surgical site infections (SSIs) are an important cause of health care-associated infection. They may be localized to the incision site or extend into adjacent deeper structures. Gastrointestinal procedures are among the highest risk procedures for SSI due to the presence of intraluminal bacteria. (See 'Introduction' above.)
●Antibiotic selection – There are two key components of antimicrobial prophylaxis for prevention of SSI following gastrointestinal procedures: antibiotic selection and timing of administration. The choice of agents depends on the type of procedure (table 1). (See 'Antimicrobial prophylaxis' above.)
•For patients undergoing clean-contaminated procedures during which the lumen of the intestinal tract is entered, antimicrobial prophylaxis with cefazolin is warranted. For patients undergoing clean procedures such as selective vagotomy and antireflux procedures, antimicrobial prophylaxis is warranted only for patients at increased risk for SSI in the setting of such procedures. (See 'Gastroduodenal procedures' above.)
•For patients undergoing open biliary tract procedures, antimicrobial prophylaxis with cefazolin is warranted. We agree with guidelines that antimicrobial prophylaxis is not warranted in low-risk patients undergoing elective laparoscopic cholecystectomy, but some experts give antibiotics to all patients undergoing cholecystectomy. (See 'Biliary tract procedures' above.)
•In the setting of uncomplicated appendicitis, antimicrobial prophylaxis is warranted; reasonable regimens include a cephalosporin with anaerobic activity (cefoxitin or cefotetan) or a first-generation cephalosporin (cefazolin) plus metronidazole. Patients with complicated appendicitis should receive preoperative antibiotics and continue therapy for at least five days. (See 'Appendectomy procedures' above.)
•For small bowel surgery without obstruction, antimicrobial prophylaxis with cefazolin is warranted. For small bowel surgery in the setting of obstruction, additional coverage for anaerobic pathogens is warranted. (See 'Small intestine procedures' above.)
•For patients undergoing hernioplasty (prosthetic mesh repair of hernia) or herniorrhaphy (suture repair of hernia), antimicrobial prophylaxis with cefazolin is warranted. The risk of SSI is higher in hernioplasty compared with herniorrhaphy. (See 'Hernia repair procedures' above.)
•For colon procedures, intravenous antimicrobial prophylaxis is warranted with a second-generation cephalosporin (cefoxitin or cefotetan) or cefazolin plus metronidazole. (See 'Colorectal procedures' above.)
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