Identification and management of the patient at high risk for wound infection

Despite the use of perioperative antibiotics, wound infection remains a major source of morbidity after contaminated head and neck cancer surgery. Most adjunctive methods designed to control wound infection include techniques to reduce bacterial wound contamination. Additional methods include predicting the high risk patient and the bacteriology of subsequent wound infection, which allows antibiotic prophylaxis to be used on a selective basis. This article reviews relevant experimental and clinical data that evaluated these methods. Based on these results, as well as personal observations, guidelines are suggested for controlling wound infection in patients undergoing contaminated head and neck surgery.     

Ineffectiveness of closed suction drainage cultures in the prediction of bacteriologic findings in wound infections in patients undergoing contaminated head and neck cancer surgery

Despite the use of perioperative antibiotics, wound infection remains a major source of morbidity after contaminated head and neck cancer surgery. Accurate preoperative indentification of the patient likely to develop wound infection or prediction of the pathogenic organisms would allow a rational approach to antibiotic prophylaxis or initiation of therapy at the first sign of infection. This prospective study of patients undergoing contaminated head and neck cancer surgery evaluated cultures from hemovac lines in the prediction of the patient at high risk for wound infection and the bacteriologic findings in subsequent wound infections. Cultures were obtained from aspirates of the hemovac lines in 30 patients; 13% (four of 30 patients) developed a wound infection. Aerobic isolates were recovered in 100% (30 of 30 patients). Pathogens were isolated from 75% (three of four) and 73% (19 of 26) of patients with and without infection, respectively. Anaerobic bacteria were recovered in 8% (two of 26) of patients. There was a correlation between hemovac isolates and the patient's subsequent recovery from the wound infection in 50% (two of four) of the infected wounds. Cultures of hemovac lines in patients undergoing contaminated head and neck cancer surgery were not predictive of the high-risk patient or the bacteriologic findings in subsequent wound infections.     

Prophylactic antibiotics in surgery and surgical wound infections

Wound infection remains a considerable cause of morbidity and mortality among surgical patients, despite the relative success of prophylactic antibiotics. In modern efforts to control healthcare costs while improving the quality of patient care, we must not overlook the basic principles of wound infections and their appropriate treatment. Predisposing factors for the development of surgical wound infection include the creation of a surgical wound, the presence of bacteria, and a susceptible host. The selection of an appropriate antimicrobial drug depends on the identification of the most likely pathogens associated with a given procedure, as well as the expected antibiotic susceptibility of those pathogens. Ideally, a prophylactic antibiotic should achieve high peak tissue concentration at the site of the wound before the first incision and should be maintained until the time of closure. Currently, the administration of prophylactic antibiotics is indicated for contaminated and clean-contaminated wounds. Despite the proven effectiveness of antibiotic prophylaxis, many researchers would argue that contemporary dosing regimens should be reevaluated. The debates concerning the dosage and timing of ideal prophylactic administration are likely to continue.     

Bacteriologic profile of surgical infection after antibiotic prophylaxis

Wound infections resulting from contamination during major head and neck surgery continue to be a critical issue. In this study, specimens of pus or draining fluids from the wounds of 43 surgical patients who received perioperative administration of ampicillin/sulbactam or clindamycin were cultured for aerobic and anaerobic isolates to the species level. Polymicrobial infections were identified in 13 of 43 patients (30%); 82% of isolates were aerobic organisms (45 of 55), and 18% were anaerobic or facultative species (10 of 55). Nine of 43 patients (21%) showed no bacterial isolates from cultured material. Independent of the primary site of malignancy or antibiotics used, nine of 25 isolates (36%) obtained from patients who underwent concomitant dental extractions, but only one of 24 (4%) who did not, developed anaerobic infections, (p < 0.001). The minimum inhibitory concentration of anaerobic isolates suggested sensitivity to the antibiotics used, and minimum bactericidal concentration data suggested that further postoperative doses may be required to adequately treat the heavily contaminated wounds. These data suggest that wound colonization following dental extraction procedures in clean contaminated head and neck surgery increases the risk of anaerobic infections. The use of a therapeutic dose and longer duration of perioperative antibiotics may be warranted.     

择期开腹结直肠手术单次预防性使用抗生素的安全性与有效性

目的探讨择期开腹结直肠手术单次预防性使用抗生素的安全性与有效性。方法回顾性分析2009年10月至2011年10月间在北京协和医院接受择期开腹结直肠手术的275例患者。所有患者于切皮前30～60min．单次静脉输注预防性抗生素。此后如无感染并发症则不再使用任何抗生素。根据术后手术部位感染、不明原因的抗生素治疗、肠道吻合口瘘以及远处感染的发生情况．综合判定为预防成功、预防失败或远处感染。结果275例患者术中和术后无一例发生抗生素相关的药物过敏反应。单次预防性使用抗生素预防成功率88．4％（243／275）,预防失败率8．4％（23／275）,远处感染9例（3．3％,9／275）。预防失败的23例中,手术部位感染13例（4．7％）,术后不明原因发热使用广谱抗生素者2例（0．7％）,术后发生肠道吻合口瘘8例（3．6％,8／222）。结论择期开腹结直肠手术单次预防性使用抗生素安全、有效。     

Prophylactic antibiotics in neurosurgery

Because of a low risk of infection (around 2-3%), prophylactic use of antibiotics in neurosurgery is a controversial issue. Some neurosurgeons consider that there are strong arguments against the use of antimicrobials (promotion of antibiotic-resistant strains of bacteria, superinfection and adverse drug reactions) and meticulous aseptic techniques could be more usefully than prophylactic antibiotics. On the other hand, despite of being rare, the consequences of a neurosurgical infection can be dramatic and may result in a rapid death, caused by meningitis, cerebritis, abscess formation or sepsis. Clinical studies emphasized that the most important factors influencing the choice of antibiotic prophylaxis in neurosurgery is the patient's immune status, virulence of the pathogens and the type of surgery ("clean contaminated"--procedure that crosses the cranial sinuses, "clean non-implant"--procedure that does not cross the cranial sinuses, CSF shunt surgery, skull fracture). Prophylaxis has become the standard of care for contaminated and clean-contaminated surgery, also for surgery involving insertion of artificial devices. The antibiotic (first/second generation of cephalosporins or vancomycin in allergic patients) should recover only the cutaneous possibly contaminating flora (S. aureus, S. epidermidis) and should be administrated 30' before the surgical incision, intravenously in a single dose. Most studies pointed that identification of the risk factors for infections, correct asepsis and minimal prophylactic antibiotic regimen, help neurosurgeons to improve patient care and to decrease mortality without selecting resistant bacteria.     

Antibiotic prophylaxis in high-risk head and neck surgery: one-day vs. five-day therapy

Patients who undergo major contaminated surgery of the head and neck benefit from perioperative antibiotic prophylaxis. This study was developed to determine if 5 days of antibiotic administration would be more effective than 1 day. A multi-institutional prospective randomized double-blind study was designed. Patients who were identified as requiring pedicled flap reconstruction were potential candidates for the study. Later, patients were randomly assigned to receive cefoperazone sodium for either 24 hours or 120 hours. In each case, the drug was administered intravenously, beginning 1 to 2 hours preoperatively and continued for the prescribed period. One hundred nine patients were evaluable. Fifty-three patients were assigned to 1 day of perioperative prophylaxis. Wound infection developed in ten patients (18.9%). Fifty-six patients were assigned to 5 days of perioperative antibiotic prophylaxis. Wound infection developed in 14 (25%) of these patients (P greater than .05). These data suggest that no beneficial effect from administration of antibiotics for longer than 24 hours postoperatively can be achieved in patients who undergo myocutaneous flap reconstruction.     

Antibiotic treatment for prevention of infectious complications in joint replacement

Prophylactic antibiotic treatment is mandatory in every operation involving an orthopedic implant. Carefully selected and correctly administered antibiotics can provide effective protection of the implant from bacterial colonization. The prevention of deep wound infection in joint replacement includes several procedures and measures which constitute three basic groups: 1) Promotion of patient's ability to resist infection (careful pre-operative preparation, elimination of potential infectious loci, good nutritional status, etc). 2) Optimal conditions for the operative wound (surgical technique, prophylactic antibiotics). 3) Reduction of the number of bacteria brought in the wound (control measures, super-sterile operating theatres). Clear rules for the system of prophylactic antibiotic treatment should be adopted. A program in which responsibility for antibiotic administration was shifted from the nursing staff to the anesthesiologist in the operating theatre showed improved outcomes and reduced costs. Poor timing of prophylactic antibiotic administration is one of the basic mistakes. If the wound happened to be contaminated during surgery, the first three post-operative hours would be most decisive for the development of infection. An effective bactericidal concentration of antibiotic should be present in tissues and serum immediately after surgery has begun. Therefore the appropriate time for antibiotic application is before a skin incision is made, and not after the operation has started; the highest serum and bone tissue levels appear 20 to 30 min. after intravenous antibiotic injection. To allow antibiotics to reach target tissues, they should be introduced at least 10 min. before tourniquet application. For long surgical procedures or when blood loss is high, an additional dose of antibiotics is recommended during the operation. If a sample for bacterial cultivation is required, antibiotic administration is postponed until during surgery. However, this is used only in indicated cases when deep infection is suspected and no assessment of the causative agent is available. Otherwise this approach carries a high risk of infectious complications in aseptic revision arthroplasty. Long-term, unjustified administration of antibiotics leads to an increase in resistance to the antibiotic involved. Some studies show that a day's course is as effective as a seven-day one. A shorter antibiotic course decreases the costs, reduces side-effects and minimizes the development of resistance. An optimal duration of antibiotic treatment has not been defined yet, and is still a hot issue for discussion. Many authors recommend one pre-operative antibiotic dose and, according to the kind of antibiotic, agree to its 24-hour administration in order to lower the toxic effect of antibiotic and to prevent selection of resistant microorganisms. The choice of suitable antibiotics for prophylactic treatment should be based on the range of agents causing joint replacement infections and the pharmacological properties of the drug. This should have minimal toxicity, should be well tolerated by the patient and, from the epidemiological point of view, should have a low risk of inducing resistance because of frequent use. Naturally, it is not possible to include all antibiotics against all causative agents and therefore attention should be paid, in the first place, to Gram-positive bacteria, i. e., staphylococci and streptococci, which are the most common causes of infectious complications associated with joint replacement. Because of difficulties related to the right choice of antibiotic, it is recommended to keep a record of complications in each patient in order to provide feedback and to facilitate the establishment of reliable antibiotic-based prevention. The prevention of infection in orthopedics is a comprehensive issue. It cannot be expected that prophylactic antibiotic treatment will compensate for mistakes made in operative protocols, for inadequate operative techniques, for shortcomings in operating theatre equipment or insufficient preparation of patients.     

An updated meta-analysis on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures

To systematically analyze published randomized trials on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures. Trials on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgery were selected and analyzed to generate summated data (expressed as risk ratio [RR]) by using RevMan 5.0. Nine randomized controlled trials encompassing 3720 patients undergoing breast surgery were retrieved from the electronic databases. The antibiotics group comprised a total of 1857 patients and non-antibiotics group, 1863 patients. There was no heterogeneity [χ(2) = 7.61, d.f. = 7, p < 0.37; I(2) = 8%] amongst trials. Therefore, in the fixed-effects model (RR, 0.64; 95% CI, 0.50-0.83; z = 3.48; p < 0.0005), the use of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures was statistically significant in reducing the incidence of surgical site infection (SSI). Furthermore, in the fixed-effects model (RR, 1.30; 95% CI, 0.89-1.90; z = 1.37; p < 0.17), adverse reactions secondary to the use of prophylactic antibiotics was not statistically significant between the two groups. Preoperative prophylactic antibiotics significantly reduce the risk of SSI after breast surgical procedures. The risk of adverse reactions from prophylactic antibiotic administration is not significant in these patients. Therefore, preoperative prophylactic antibiotics in breast surgery patients may be routinely administered. Further research is required, however, on risk stratification for SSI, timing and duration of prophylaxis, and the need for prophylaxis in patients undergoing breast reconstruction versus no reconstruction.     

Guidelines for perioperative antibiotic use in digestive tract surgery

Guidelines for the use of antibiotics in postoperative infections after digestive tract surgery have been under discussion in Japan since the mid-1980s, when the number of infections with methicillin-resistant Staphylococcus aureus began to increase. It is important to make a distinction between prophylactic and therapeutic antibacterial administration in the perioperative period. Prophylactic antibacterial administration to prevent postoperative infection is necessary to prevent surgical site infection and remote infection from invading the surgical site. Because the type of bacterial contamination of the surgical site differs with the organ undergoing surgery, the type of antibiotic selected also differs. Antibiotic administration to prevent postoperative infection after surgery requiring a short time to perform may be started preoperatively. In patients undergoing prolonged surgery, antibiotics are administered every 3 hours. If an antibacterial agent is administered for 3-4 days, there is a risk of the development of resistance and therefore administration should not exceed 3-4 days, including the day of surgery. However, during surgery in which bacterial contamination is already evident, the therapeutic use of antibiotics should be initiated at diagnosis. For example, toxinemia is common in many cases of colon rupture and the administration of powerful antibiotics is necessary to save patients' lives.     

A questionnaire survey on the theory of postoperative infection prophylaxis in urologic surgery

The implementation of the Japanese guidelines for prevention of postoperative infection in urological surgery, based on the Centers for Disease Control and Prevention (CDC) was surveyed. In October 2006, questionnaires about selection of prophylactic antibiotics, timing and period of administration, were distributed to 25 urologists. Surgical procedures were classified into four categories by contamination levels: 1. clean surgery, 2. clean-contaminated surgery, 3. contaminated surgery (surgery with urinary tract diversion using the intestine), and 4. laparoscopic surgery. Implementation of recommendations was about 70% in the selection of prophylactic antibiotics, and 20-30% for the timing of administration in four categories. Adequate implementation was low for the timing of administration. Period of administration in contaminated surgery was longest in all categories. Concerning the administration period and the selection of antibiotics for contaminated surgery, marked differences from recommendations were seen. Therefore further education in hospitals in Japan is needed.     

Factors influencing the development of wound infection following free-flap reconstruction for intra-oral cancer.

Wound infection following tissue transfer in head and neck oncology is common. Factors known to be associated with infective complications include blood transfusion, pre-operative radiotherapy, duration of surgery, duration of pre-operative stay and a history of smoking. The present study specifically examined 100 consecutive patients on a standard antibiotic protocol undergoing free flap reconstruction following resection of cancers of the oral cavity or oropharynx. Despite prophylactic antibiotics, 21 patients developed a head and neck wound infection. No statistically significant association was found between infective wound complications and a history of smoking, pre-operative radiotherapy or chemotherapy, length of pre-operative hospital stay, duration of surgery, or number of units of blood transfused. We conclude that, in this group of patients, wound infection is a common and difficult problem, but with no statistically significant association with any of the variables studied.     

The usefulness of conducting investigations on intra-abdominal bacterial contamination in digestive tract operations

A bacteriological study of 108 cases of gastrointestinal surgery was conducted by analyzing intra-abdominal bacterial contamination (IABC) and postoperative surgical site infections (SSI). We utilized an anaerobic porter to detect intra-abdominal bacterial infection and transport bacteria to the laboratory. The positive IABC rate was 42.9% for gastric cancer surgery, 22.6% for biliary tract surgery, and 85.7% for colorectal cancer surgery. Most cases of SSI were IABC-positive, and isolated bacterial species from the SSI were similar to those from the IABC. In colorectal cancer surgery, a preoperative chemical intestinal preparation and the prophylactic use of antibiotics had a major influence on the sensitivity of bacteria isolated from the SSI. These data suggest that prophylactic antibiotics should be chosen from among those to which bacteria from the IABC are highly sensitive, and that therapeutic antibiotics should be chosen from among those to which bacteria isolated from the SSI are highly sensitive. Finally, the exploration of IABC enables us to predict the incidence of SSI.     

The prevention of wound infection after head and neck resections: a pilot study using gentamicin impregnated beads

A pilot study of 16 patients undergoing major head and neck resections is presented. At the end of surgery gentamicin (Garamycin) chains are inserted into the wound prior to skin closure and left in place for 48 hours. The rate of wound infection is shown to be low (6.25% requiring antibiotics, 18.75% overall); there have been no complications from use of the chains.     

Prophylactic antibiotics in orthopaedic surgery

The use of prophylactic antibiotics in orthopaedic surgery is effective in reducing surgical site infections in hip and knee arthroplasty, spine surgery, and open reduction and internal fixation of fractures. To maximize the beneficial effect of prophylactic antibiotics while minimizing adverse effects, the correct antimicrobial agent must be selected, the drug must be administered just before incision, and the duration of administration should not exceed 24 hours.     

Role of aerobic gram-negative rods, anaerobes, and fungi in wound infection after head and neck surgery: implications for antibiotic prophylaxis

The prevention of wound infection after major contaminated head and neck surgery is a critical issue for the head and neck surgeon. The proper interpretation of cultures taken from wounds is uncertain. Multiple organisms are invariably isolated from this nonsterile site including indigenous aerobic and anaerobic flora, aerobic gram-negative rods, and fungi. We present evidence from controlled antibiotic trials that demonstrate the pathogenicity of oropharyngeal anaerobic flora. The presence of aerobic gram-negative rods and fungi generally represent colonization and antibiotic coverage need not routinely be directed at these organisms. On the other hand, the antibacterial spectrum of an agent used for head and neck would prophylaxis should include coverage for pathogenic oral flora, namely the gram-positive aerobic cocci (especially streptococci) and anaerobic bacteria.     

Head and neck surgery in the aged

This study was carried out to determine the perioperative mortality rate of patients over the age of 65 years who are undergoing major head and neck resections under general anesthesia. The total number of patients was 810 and the perioperative mortality rate (death within 30 days of operation) was 3.5 percent (29 of 810). This rate is relatively low when compared with the rate for patients undergoing similar procedures during the same period in the 35 to 65 years age group. Since 1975 reports of other types of surgery in the elderly have given perioperative mortality rates of from 4.8 to 26 percent. Previous studies of head and neck surgery in the elderly have given perioperative mortality rates of from 1.3 to 13.6 percent. Head and neck surgery in the elderly continues to be a safe procedure when compared with other types of surgery. As the portion of patients in the population over the age of 65 continues to increase, advanced age alone should not be a deterrent to performing aggressive surgical therapy for head and neck cancer.     

Postcholecystectomy wound infection. The impact of prophylactic antibiotics on the epidemiology of infections

The clinical courses of 347 patients undergoing gallbladder surgeries were monitored to study the epidemiology of postcholecystectomy wound infection in a hospital in which high-risk patients received prophylactic antibiotics. Overall, 3.8% of patients had wound infections. Patients who had positive bile cultures taken during surgery or positive intraoperative wound cultures had higher rates of infection than patients with negative cultures. However, there was a poor correlation among the bacterial isolates that were recovered from the bile or the wound surface during surgery and from postoperative infections. Antibiotic-sensitive enteric bacteria were recovered from bile samples at surgery, gram-positive organisms and enteric gram-negative bacteria were isolated from intraoperative cultures of the wound surface, and antibiotic-resistant gram-negative bacteria or enterococci were recovered from wounds that developed postoperative infections. There was a strong association between the prior receipt of prophylactic antibiotics and infections with antibiotic-resistant bacteria. Data suggest that bactibilia is still an important epidemiologic marker that identifies patients at high risk for subsequent wound infection. However, in patients who have received prophylactic antibiotics, intraoperative cultures cannot be relied on to guide the choice of empiric therapeutic antibiotics for postoperative infections. Bacteria responsible for these infections are not identified by cultures taken at the time of surgery and are often resistant to the class of antibiotics used for prophylaxis.     

The effects of topical oral clindamycin antibiotic rinses on the bacterial content of saliva on healthy human subjects.

The use of systemic antibiotics for major head and neck surgical procedures involving the upper aerodigestive tract is now accepted as an important part of perioperative patient care. Despite knowledge of the high counts of bacteria present in saliva, no preoperative regimen for preparing the mouth has been standardized. Surgical wounds come in contact with saliva during the course of many head and neck procedures. While wound infection rates have been decreased with the use of prophylactic systemic antibiotics, serious morbidity still exists from postoperative wound infections. Reducing the bacterial counts in saliva preoperatively may further decrease wound infection rates. A prospective randomized pilot study of twenty healthy human subjects compared the effects of an oral rinse with clindamycin vs. a placebo rinse of normal saline. There was a statistically significant reduction in both aerobic and anaerobic colony counts in the clindamycin group at 4 hours after treatment. For the group that rinsed with placebo, there was an actual increase in counts 4 hours after treatment. It is concluded that oral rinses with clindamycin can reduce the bacterial content of saliva for a sufficient length of time to be effective as a preoperative prophylactic measure for head and neck surgery involving the upper aerodigestive tract. Future studies are planned to evaluate other potentially effective agents. A logical continuation is a clinical study of preoperative and postoperative rinses.     

Prophylactic cefazolin in gastric bypass surgery

Because surgery in obese patients is associated with a high risk of infection, gastric bypass procedures offer an excellent opportunity to test the efficacy of prophylactic antibiotics. Accordingly, a double-blind prospective trial of prophylactic cefazolin was carried out in 53 consecutive patients who underwent gastric bypass surgery for morbid obesity. The patients were randomized to two treatment arms: (1) cefazolin intravenously, 1 gm 2 hours prior to surgery, at induction of anesthesia, and then 0.5 gm every 6 hours for 48 hours, or (2) an indistinguishable placebo of 5% dextrose at identical intervals. Serial cultures were taken at operation and in the postoperative period. Antibiotic levels of fat were measured by tissue extraction and B. subtilis assay. After surgery, patients were monitored for infection by clinicians unaware of their random assignment group. The study was terminated and the code broken when it was evident that wound infections were increased to a statistically significant difference in one arm of the study. The brief perioperative administration of cefazolin reduced the incidence of wound infection from 21% to 4% (P less than 0.05) and the incidence of urinary tract and pulmonary infections from 17% to 0% (P less than 0.05). Tissue levels of antibiotics confirmed adequate dosages in the test subjects. The advantages of prophylactic administration of cefazolin for gastric bypass procedures are clearly demonstrated in this study. This confirms other reports which have shown prophylactic antibiotics to be useful in a variety of procedures. These studies suggest the need to reconsider the traditional opposition to prophylactic antibiotics and to determine whether perioperative antibiotics should be used routinely in all major operations.