Antimicrobial prophylaxis in colorectal surgery: a systematic review of randomized controlled trials

Correlation between postoperative infections and long-term survival after colorectal resection for cancer

INTRODUCTION

Predicting long-term survival and cancer recurrence in patients with colorectal cancer is difficult because of the many factors that may affect the prognosis. This study investigated the prognostic significance of postoperative infections for patient outcome.

METHODS

From an electronic database we selected 192 patients undergoing elective radical surgery for Dukes' stage B and C colorectal adenocarcinoma. The five-year survival rates were analyzed by the Kaplan-Meier method. Univariate and multivariate analyses were carried out to evaluate the potential prognostic variables using the Cox proportional hazard model.

RESULTS

Forty-three patients developed deep incisional or organ/space surgical site infections, while the remaining 149 were complication free. The two groups were comparable for baseline, surgical and histopathological characteristics. At univariate analysis, Dukes' stage and infections were negative prognostic factors, while peritumoral infiltration of lymphocytes and eosinophils and fibrotic tissue appeared as protective variables. However, multivariate analysis showed that only Dukes' stage (P = 0.048) and occurrence of postoperative infectious complications (P = 0.011) were independently associated with outcome. In patients with infectious complications, the survival rate was significantly lower than in patients without infections (log-rank = 0.0004).

CONCLUSIONS

The present results suggest the importance of evaluating other variables besides tumor stage in the prediction of long-term outcome. In prognostic studies more attention should be paid to postoperative infections.

The use and abuse of antibiotics in elective colorectal surgery: The Saga Continues…

BACKGROUND

The role of antibiotic prophylaxis in preventing post-operative complications in patients undergoing elective colorectal surgery is well established. Despite evidence that a single-dose prophylaxis is sufficient, the duration of antibiotic use in clinical practice is highly variable and surveys have identified persistent patterns of antibiotic abuse in elective colorectal surgery.

MATERIALS AND METHODS

We conducted a retrospective review of all patients who underwent elective colorectal surgery between 1998 and 2002 at the American University of Beirut Medical Center. A survey among general surgeons in Lebanon was also performed to investigate the pattern of antibiotic prophylaxis used in such cases. The MEDLINE database (1966-2004) was searched for English-language articles and abstracts on antimicrobial use in elective colorectal surgery. Papers cited in relevant primary articles were also reviewed. Data were extracted and reviewed by all authors.

RESULTS

Two hundred and eleven matching patient-records were identified. A triple regimen including metronidazole, ampicillin and an aminoglycoside was the most commonly used preoperative prophylactic method. Patients received post-operative antibiotics for a mean of 6.66+/-2.62 days. The mean duration of post-operative antibiotic prophylaxis used by the interviewed surgeons was 4.31+/-1.08 days.

CONCLUSIONS

Our study confirms that even when strong evidence exists, surgeons fail to adhere to antibiotic prophylaxis guidelines. This pattern is not unique to Lebanon but is shared to a large extent by surgeons around the world. Adherence to published guidelines and improved education of surgeons are essential to the delivery of cost-effective medical practice.

The significance of the intraoperative repeated dosing of antimicrobials for preventing surgical wound infection in colorectal surgery

PURPOSE

It is widely accepted that antimicrobial prophylaxis is useful for the prevention of surgical wound infection, especially in colorectal surgery. While many reports support the finding that the first dose should be administered immediately before surgery, there is less evidence concerning the ideal timing for the second dose. The purpose of this study is to examine the significance of intraoperative repeated dosing.

METHODS

A surgical series of 131 patients with primary colorectal cancer was retrospectively analyzed for 14 parameters, including the protocols of antimicrobial administration to determine the clinical risk factors for surgical wound infection.

RESULTS

The overall surgical wound infection rate of the 131 patients was 16.0% (21/131). When the operation finished within 4 h after the first dose (n = 29), wound infection was observed in only one patient (3.4%). In a prolonged operation exceeding 4 h after the first dose, the surgical wound infection rates were 8.5% and 26.5%, respectively, for those with (n = 47) and without (n = 49) intraoperative repeated dosing, which were significantly different based on both a univariate analysis (P = 0.031) and a multivariate analysis (P = 0.0079).

CONCLUSION

Intraoperative repeated antimicrobial dosing is therefore recommended to prevent the surgical wound infection for prolonged colorectal surgery.

Perioperative antibiotics and practice

Perioperative antibiotic administration and anesthetic practice have major impacts on infectious complications. Anesthesiologists need to place high importance on perioperative antibiotic administration to allow patients to receive optimal benefit from this therapy and to minimize risk. Many aspects of perioperative care ranging from thermoregulation to glycemic control may have profound longterm affects on infection rate and thereby patient outcome.

The release of cefazolin and gentamicin from biodegradable PLA/PGA beads

Infection has been one of the most common causes of problems and complications after the operation despite the advance in surgical techniques and the availability of newly developed antibiotics. Local antibiotic delivery beads for treatment of various surgical infections had been studied recently especially in osteomyelitis. This current paper used cefazolin sodium and gentamicin sulfate combined with biodegradable polymers (50:50 poly(DL-lactide):co-glycolide) as antibiotic beads for a long-term drug release. To manufacture an antibiotic bead, polylactide-polyglycolide copolymers were mixed with the antibiotics. The mixture was compressed and sintered at 55 degrees C to form beads of different sizes. The beads were placed in 3 ml of phosphate buffered saline and incubated at 37 degrees C. An elution method combined with a bacterial inhibitory test was employed to characterize the release rate of the antibiotics over a 30-day period. The results suggested that the biodegradable beads released high concentrations of antibiotic (well above the minimum inhibitory concentration) in vitro for the period of time needed to treat bone infection; i.e. 2-4 weeks. This provides advantages as a first line choice of long-term antibiotics for patients with osteomyelitis and various infections such as thoracic, abdominal, and pelvic infections, as well as for the prophylaxis of these infections.

Risk factors for mortality and morbidity after elective sigmoid resection for diverticulitis: prospective multicenter multivariate analysis of 582 patients

The prevalence of diverticular disease of the colon is increasing in occidental countries. It would be useful to further decrease the mortality and morbidity after elective sigmoid resection (ESR) for diverticulitis. The aim of this study was to identify modifiable preoperative and intraoperative risk factors for mortality and morbidity after ESR for diverticulitis. A database of 2615 patients who underwent a colon or rectal resection with primary anastomosis between 1985 to 1998 has been constructed from prospective randomized studies published by a French surgical group. Of those patients, 582 had undergone ESR for diverticulitis, and they constitute the population of the present study. A total of 46 potential preoperative and intraoperative risk factors for mortality and morbidity have been studied by univariate and multivariate analysis. The operative mortality for our series was 1.2%, and the overall morbidity was 24.9%. The multivariate analysis revealed two statistically significant independent risk factors of mortality: age >75 (odds-ratio=7.9; 95% confidence interval [CI 1.7-36.6]; p=0.01) and obesity (odds-ratio=5.2; 95% CI [1.1-27.9]; p=0.04). The abdominal morbidity (AM) was 6.5% (38/582). The absence of antimicrobial prophylaxis administration with ceftriaxone was the only significant risk factor for AM in multivariate analysis (p=0.003; odds-ratio=2; 95% CI [1.1-4]). The extraabdominal morbidity (EAM) was 18.4% (107/582). Both chronic pulmonary disease (p=0.008; odds-ratio=2.9; 95% CI [1.4-6]; p=0.008) and cirrhosis (odds-ratio=12; 95% CI [1.2-120]) proved to be significant risk factors for EAM. Weight control prior to surgery, routine administration of prophylactic preoperative antibiotics, and preoperative optimization of the respiratory status of patients with chronic pulmonary disease could decrease the postoperative mortality and morbidity associated with ESR for diverticulitis.

Prophylaxis of Infection for Elective Colorectal Surgery

BACKGROUND

Influenced by the key results of the clinical trials conducted in the early 1970s by Condon, Nichols, and Gorbach, surgeons have adopted the routine use of mechanical bowel prep and antimicrobial prophylaxis prior to elective colorectal procedures as a widely established practice. Recent clinical trial data, however, led us to reexamine the benefits of mechanical bowel preparation, methods of antimicrobial prophylaxis and to assess the role of new, specific risk factors for surgical site infection after colorectal operations.

METHODS

Pertinent studies on antimicrobial prophylaxis for elective colorectal surgery were identified from a Medline search of English language publications since 1966.

RESULTS

We found credible clinical trial data that mechanical bowel preparation prior to elective colorectal surgery may not be essential. Timing of the administration of prophylactic antimicrobials is often inaccurate in current practice and suggests the need for a long-acting, broad-spectrum agent that would deemphasize precision in time of preoperative infusion. New risk factors have been identified that increase infection after colorectal surgery, including patient core temperature and tissue oxygenation. Independent observers identify postoperative surgical site infection at a higher rate than physician self-reporting and should be incorporated into future clinical trials.

CONCLUSION

The once settled area of antimicrobial prophylaxis for colorectal surgery is again controversial. Cooperative clinical trials will be needed to resolve key questions such as the efficacy for bowel preparation and how to obtain effective timing of antimicrobial prophylaxis.

Trends in Preparation for Colorectal Surgery: Survey of the Members of the American Society of Colon and Rectal Surgeons

The utility of antibiotic and mechanical preparation for colorectal surgery is controversial, and numerous different regimens are used. The aim of this study was to detect trends in preparation for surgery among American colon and rectal surgeons. Members of the American Society of Colon and Rectal Surgeons practicing in the United States were surveyed with a postal questionnaire regarding their routine preparations for colon and rectal surgery. Five hundred fifteen (40%) of the 1295 questionnaires sent were returned. Eighty-one per cent of the respondents had completed an accredited colorectal training program, and the average experience in practice was 13.7 (±8.7) years. Half of the surgeons felt that prophylactic oral antibiotic is essential, 41 per cent felt it was doubtful, and 10 per cent considered oral prophylaxis unnecessary. Despite these statements 75 per cent of the surgeons routinely utilized oral antibiotics (96% of them used a combination of two drugs), 11 per cent used them selectively, and only 13 per cent omitted oral prophylaxis from their practice. Similarly although the usefulness of intravenous antibiotics was questioned by 11 per cent of the surgeons 98 per cent routinely used them. The average number of postoperative doses was two (±1.9). Although 10 per cent of the surgeons questioned the importance of mechanical preparation more than 99 per cent routinely used it. Forty-seven per cent of the surgeons used sodium phosphate, 32 per cent used polyethylene glycol, and 14 per cent alternated between these two options. We conclude that although the use of oral antibiotic prophylaxis for colorectal surgery is controversial among surgeons it is still routinely practiced by 75 per cent. Intravenous antibiotic prophylaxis and mechanical cleansing, however, are still a dogma and almost invariably used. There is a trend toward the use of a shorter course of postoperative intravenous antibiotics and the use of sodium phosphate for mechanical cleansing.

The identification of barriers preventing the successful implementation of a surgical prophylaxis protocol

AIM

The aim of this study was to introduce a protocol for the use of antimicrobials in surgical prophylaxis for the described procedures in Antrim Area Hospital.

METHOD

Historical data of antimicrobial use were obtained from retrospective analysis of patients' charts, for those patients identified as having one of the following 'clean/contaminated' surgical procedures over the previous six months; cholecystectomy or abdominal hysterectomy. These data were analysed, and a protocol was introduced providing guidelines for the choice of antimicrobial agent, its administration time, route, dose, duration and frequency of treatment.

MAIN OUTCOME MEASURE

The main outcome measure was the success of the uptake of the protocol following its implementation.

RESULTS

There was a total of 285 patients identified, 105 prior to and 180 post implementation. Overall, 68% of patients received some form of prophylaxis in the first cycle, and 72% in the second.

CONCLUSION

Although the introduction of the protocol led to slight improvements in compliance with standard prescribing procedures, with an increase in single-dose prophylaxis, and a reduction in prolonged prophylactic treatment, the improvements did not reach expectations. This paper attempts to identify the possible barriers to protocol implementation.

Antibiotic prophylaxis in elective colorectal surgery

BACKGROUND

Antibiotics are often administered in elective colorectal surgery to prevent wound infection. The tendency for surgeons to prolong the administration of prophylactic antibiotic therapy in the postoperative period is a well-known fact. The aim of this study was to elucidate the pattern of prophylactic antibiotic utilization in elective colorectal surgery and to determine if evidence-based medicine is employed in relation to this practice.

METHODS

A cross-sectional study encompassing general surgeons performing elective colorectal surgery was performed. Questionnaires were distributed to 144 surgeons (national, academic and private health care). Questions pertaining to the type, timing and duration of antibiotic administration were asked. The prevalence of wound infection audit rate and whether or not there were specific guidelines related to antibiotic administration were also determined.

RESULTS

The response rate obtained was 67% (n = 96). Although evidence from the current medical literature and recommended national guidelines support the use of single-dose prophylactic antibiotics, 72% of the respondents used more than a single dose. Forty surgeons (42%) claimed that their prescribing practice was supported by the medical literature, 31 respondents (32%) based their practice on hospital guidelines and personal preference was cited as a reason by 21 surgeons (22%). The remaining four respondents (4%) used a similar scheduling policy to that practiced by their colleagues in relation to antibiotic administration. There was no significant difference in antibiotic dose scheduling between national, private and university academic institutions (P = 0.85).

CONCLUSIONS

These results suggest that a significant proportion of surgeons administer excessive and unnecessary doses of antibiotics in elective colorectal surgery. Further studies are required to uncover the reasons but lack of appropriate guidelines and failure to exercise evidence-based medicine are major factors that account for this practice.

Surgery for colorectal cancer

Colorectal cancer remains the second commonest cause of cancer death in North America and Western Europe. Surgery remains the mainstay of treatment. The aim of surgery should be to achieve cure and to avoid locoregional recurrence. The fixity of the primary tumour determines resectability, and the extent of spread determines ultimate survival. Patients with rectal cancer present a particular problem. There is good evidence that lower local recurrence rates may be achieved both by improvements in surgical technique and the use of adjuvant radiotherapy. The importance of adequate treatment of the circumferential tumour margin cannot be over-emphasised; meticulous attention is required to ensure an adequate circumferential excision. The lowest incidences of locoregional recurrence are reported by surgeons who perform total mesorectal excision. Anorectal function, sexual and urinary dysfunction may occur after rectal excision. Both postoperative and pre-operative radiotherapy can reduce the incidence of local recurrence. However, in view of the low recurrence rates obtained with TME alone, the role of adjuvant radiotherapy requires further evaluation. Several aspects of the surgical management of colorectal cancer, for example, the role of transanal local excision of selected rectal cancers and laparoscopic surgery, the management of obstructed cases and the role of follow-up remain to be defined clearly.

Complications after colorectal surgery without mechanical bowel preparation

BACKGROUND

The current practice of mechanical bowel preparation (MBP) before colorectal surgery is questionable. Mechanical bowel preparation is unpleasant for the patient, often distressful, and potentially harmful. The results are often less than desired, increasing the risk of contamination. Cleansing the colon and rectum before surgery has never been shown in clinical trials to benefit patients. In animal experiments MBP has a detrimental effect on colonic healing.

STUDY DESIGN

To investigate the outcomes of colorectal surgery without MBP, we prospectively evaluated a consecutive series of patients who underwent resection and primary anastomosis of the colon and upper rectum, including emergency operations. One surgeon performed all operations. Endpoints were wound infection, anastomotic failure, and death. Late signs and symptoms that might be secondary to leakage of the anastomosis were considered as an anastomotic failure as well, during a followup of 1 year.

RESULTS

Two hundred fifty operations were performed, of which 199 (79.6%) were elective. Colectomies were left-sided in 65.6%. Anastomoses were ileocolic in 32%, colocolic in 20.8%, colorectal intraperitoneal in 34.4%, and extraperitoneal in 12.8%. No patient suffered from fecal impaction. Followup was complete in 97.2%. Eight patients (3.3%; 95% confidence interval [CI]: 1.4-6.4) developed superficial wound infections. In three patients there was leakage from an extraperitoneal colorectal anastomosis, in two of them after hospital discharge. The overall anastomotic failure rate was 1.2% (95% CI: 0.3-3.6). The in-hospital mortality rate was 0.8% (95% CI: 0.1-2.9) and was not related to abdominal or septic complications.

CONCLUSION

Mechanical bowel preparation is not a sine qua non for safe colorectal surgery.

Infectious diseases in gynecologic oncology: an overview

The increasing trend of a multimodal therapeutic approach in gynecologic oncology in the last few years has markedly changed the nature, frequency, and clinical presentation of infectious diseases. Despite the improved diagnostic tools, refined surgical technique, and routine use of prophylactic antibiotics, the morbidity and mortality of infectious complications remain significant. The rational use of available treatment resources, the recognition of risk factors, and increased awareness of host-cancer interactions should reduce the incidence of these serious infectious complications. The improved prevention and more efficient treatment of infections in the gynecologic oncology patient will not only improve prognosis but also have a significant economic impact as well.

The prevention of wound infection in patients undergoing colorectal surgery

Colorectal operations are, at best, clean-contaminated procedures, and at times there is gross contamination of both the peritoneal cavity and the surfaces of the surgical wound. In addition, the diseases of the large bowel that require surgery tend to afflict elderly patients. Collectively, the combination of an unclean environment, major surgery and debilitated patients creates a situation that is associated with a very high incidence of wound infection. This review documents the considerable support from clinical trials and meta-analyses that exists for the prophylactic use of a single dose of a suitable parenteral antimicrobial agent. In addition, although the evidence is less clear cut, it does not appear that the use of mechanical bowel preparations reduces the incidence of wound infections after colorectal surgery.

Infection control in the ICU

Nosocomial infections (NIs) now concern 5 to 15% of hospitalized patients and can lead to complications in 25 to 33% of those patients admitted to ICUs. The most common causes are pneumonia related to mechanical ventilation, intra-abdominal infections following trauma or surgery, and bacteremia derived from intravascular devices. This overview is targeted at ICU physicians to convince them that the principles of infection control in the ICU are based on simple concepts and that the application of preventive strategies should not be viewed as an administrative or constraining control of their activity but, rather, as basic measures that are easy to implement at the bedside. A detailed knowledge of the epidemiology, based on adequate surveillance methodologies, is necessary to understand the pathophysiology and the rationale of preventive strategies that have been demonstrated to be effective. The principles of general preventive measures such as the implementation of standard and isolation precautions, and the control of antibiotic use are reviewed. Specific practical measures, targeted at the practical prevention and control of ventilator-associated pneumonia, sinusitis, and bloodstream, urinary tract, and surgical site infections are detailed. Recent data strongly confirm that these strategies may only be effective over prolonged periods if they can be integrated into the behavior of all staff members who are involved in patient care. Accordingly, infection control measures are to be viewed as a priority and have to be integrated fully into the continuous process of improvement of the quality of care.

Antimicrobial prophylaxis for abdominal surgery: is there a need for metronidazole?

The objective of the present multicenter observational study was to assess postoperative infections as a function of risk factors and antibiotic prophylaxis under everyday clinical conditions. 2513 patients from 114 centers in Germany who received infection prophylaxis prior to elective colonic resection were included in the study between 1st September 1996 and 30th September 1997. In the descriptive analysis of the study it was noted that 36.1% of the patients had received no prophylaxis with metronidazole despite the fact that the study protocol recommended the use of this drug in preoperative antibiotic combinations. The present analysis therefore considers the influence of metronidazole on the postoperative infection rate. To exclude any bias due to intergroup differences in risk profile, the groups with and without metronidazole were subjected to a matched-pair analysis. Matching parameters were: duration of operation, blood loss, age, diabetes mellitus, hepatic, renal, or chronic airways disease, immunosuppressive therapy, and rectal resection. This led to the formation of 800 pairs that were matched with respect to these parameters. The 800 pairs were then stratified into the following treatment groups: Group 1: long-acting cephalosporin (ceftriaxone) with or without metronidazole (n = 2 x 491); Group 2: short-acting cephalosporins with or without metronidazole (n = 2 x 133); Group 3: broad-spectrum penicillins with or without metronidazole (n = 2 x 176). In all three treatment groups combination therapy with metronidazole was found to be significantly superior. Postoperative infection rates with and without metronidazole were 9.4% and 18.7% respectively in Group 1, 12.0% and 25.6% respectively in Group 2, and 19.9% and 29.0% respectively in Group 3. The lowest infection rate was thus achieved by means of preoperative infection prophylaxis with ceftriaxone plus metronidazole. Thus, preoperative administration of metronidazole in addition to a long-acting beta-lactam antibiotic is strongly advised in elective colon surgery, as absence of antibiotic cover against anaerobic colonic flora leads to a significantly higher postoperative infection rate.

Bowel preparation for colorectal surgery

PURPOSE

The aim of this study was to assess recent literature regarding bowel preparation for colonoscopy and surgery.

METHODS

The study was conducted by an Index Medicus English-language search of articles relevant to both oral mechanical and parenteral and oral antibiotic preparation for elective colorectal surgery and mechanical bowel preparation for colonoscopy. The study period was from 1975 to 2000. In addition, studies of elective colorectal surgery without mechanical bowel preparation were also considered.

RESULTS

Although several recent prospective, randomized trials have suggested that elective colorectal surgery can be safely performed without any mechanical bowel preparation, mechanical bowel preparation remains the standard of care, at least in North America at the present time. A recent survey of the members of The American Society of Colon and Rectal Surgeons revealed that the majority currently use sodium phosphate for bowel preparation and use a dual oral antibiotic regimen before elective colorectal surgery, combined with two doses of parenteral antibiotics. Although some of the use patterns are based on prospective, randomized study, others seem founded strictly on habit and theory.

CONCLUSIONS

The current methods of bowel cleansing for both colonoscopy and surgery include sodium phosphate and polyethylene glycol; colorectal surgeons practicing in North America currently prefer sodium phosphate. Additional preparation for colorectal surgery includes perioperative parenteral antibiotics and, to a slightly lesser degree, preoperative oral antibiotic preparation. Although some recent prospective, randomized studies have suggested that omission of mechanical bowel preparation for elective colorectal surgery is not only feasible but potentially preferable, caution is recommended before routinely omitting these widely practiced measures, because data to support such routine omission are limited.

Risk factors for surgical site infection after elective resection of the colon and rectum: a single-center prospective study of 2,809 consecutive patients

OBJECTIVE

To identify the risk factors for surgical site infection (SSI) in patients undergoing elective resection of the colon and rectum.

SUMMARY BACKGROUND DATA

SSI causes a substantial number of deaths and complications. Determining risk factors for SSI may provide information on reducing complications and improving outcome.

METHODS

The authors performed a prospective study of 2,809 consecutive patients undergoing elective colorectal resection via laparotomy between February 1995 and December 1998 at a single institution. The outcome of interest was SSI, which was classified as being incisional or organ/space with or without clinical leakage. A likelihood ratio forward regression model was used to assess the independent association of variables with SSIs.

RESULTS

The overall SSI, incisional SSI, and organ/space SSI with and without clinical anastomotic leakage rates were 4.7%, 3%, 2%, and 0.8%, respectively. Risk factors for overall SSI were American Society of Anesthesiology (ASA) score 2 or 3 (odd ratio [OR] = 1.7), male gender (OR = 1.5), surgeons (OR = 1.3-3.3), types of operation (OR = 0.3-2.1), creation of ostomy (OR = 2.1), contaminated wound (OR = 2.9), use of drainage (OR = 1.6), and intra- or postoperative blood transfusion (1-3 units, OR = 5.3; >/=4 units, OR = 6.2). However, SSIs at specific sites differed from each other with respect to the risk factors. Among a variety of risk factors, only blood transfusion was consistently associated with a risk of SSI at any specific site.

CONCLUSIONS

In addition to ASA score and surgical wound class, blood transfusion, creation of ostomy, types of operation, use of drainage, sex, and surgeons were important in predicting SSIs after elective colorectal resection.

Septic complications of elective laparoscopic colorectal resection

BACKGROUND

We set out to determine the rate and pattern of septic complications of the surgical wound, abdominal cavity, and urinary and respiratory tracts following laparoscopic colorectal resection.

METHODS

A longitudinal database of 500 consecutive cases of colorectal resections was reviewed.

RESULTS

The total wound infection rate was 7.2% (36/500) and included infections of the abdominal wall wounds (32/500, 6.4%) and the perineal wounds (4/50, 8%). The anastomotic leak rate in 418 patients who underwent resection with primary anastomosis was 3.3% (14/418). Intraabdominal abscesses were diagnosed in 1% (5/500) of patients. Urinary tract infections were rare (3/500, 0.6%), as was postoperative pneumonia (6/500, 1%).

CONCLUSIONS

This study confirms the low rate of postoperative pneumonia observed with all other minimally invasive procedures. Intraabdominal abscesses, urinary tract infections, and postoperative pneumonia occur considerably less frequently than in reported historical controls for open surgery. The rates of abdominal wound infection and anastomotic leak in laparoscopic colorectal resection appear to be equivalent to traditional surgery, whereas the rate of perineal wound sepsis is lower. Comparative studies are needed to determine the differential costs of the septic episodes associated with the two approaches.

Glucose is absorbed in a sodium-dependent manner from forestomach contents of sheep

Intraruminal glucose is thought to be completely converted to short-chain fatty acids (SCFA) by symbiotic microorganisms. Nevertheless, earlier in vitro studies evidenced the expression of the sodium glucose-linked transporter (SGLT)-1, in the ovine ruminal epithelium. The present study aimed to determine whether the ruminal SGLT-1 is functionally important in vivo. In a first experimental series using the emptied, washed, and isolated reticulorumen of sheep, 6.3% of glucose was absorbed from an intraruminal buffer solution (2 L, 128 mmol/L Na(+), 0.5 mmol/L glucose, 0 mmol/L galactose) within 30 min (P < 0.001). Reducing Na(+) concentration to 10 mmol/L resulted in complete inhibition of glucose absorption, and the addition of 10 mmol/L galactose (at 128 mmol/L Na(+)) induced a small but insignificant inhibition. In a second experimental series, the addition of 12 mmol/L glucose to an initially glucose-free buffer led to an increase in the transruminal potential difference from 34.4 to 37.1 mV within 4 min (P < 0.001). From the 12 mmol/L glucose-containing buffer, 11.0% of glucose was absorbed within 30 min (P < 0.05). In all experiments, microbial glucose degradation in the reticulorumen was prevented by adding cefuroxime (100 mg/L) and colistin methanesulfonate (25 mg/L) to the buffer solution. The effectiveness of antimicrobial treatment was verified by ex vivo incubations of buffer samples drawn from the reticulorumen. We conclude that glucose is absorbed in a sodium-dependent manner from the reticulorumen at low and high glucose concentrations. Absorption at high glucose concentrations is of nutritional importance because it counteracts the genesis of ruminal lactic acidosis.

A prospective, randomized, double-blind studyof single high dose versus multiple standard dose gentamicin both in combination withmetronidazole for colorectal surgicalprophylaxis

Single, high dose regimens of gentamicin plus metronidazole for colorectal surgical prophylaxis have not been adequately studied. Patients received single high dose gentamicin (4.5 mg/kg) plus metroni-dazole (500 mg) preoperatively or multiple standard dose gentamicin (1.5 mg/kg) plus metronidazole (500 mg) preoperatively and every 8h for 24h postoperatively. The deep surgical site infection (SSI) rates were 8.1% (6/74) and 6.9% (5/72) in the single high dose and multiple standard dose groups, respectively (P= 0.94). There was a trend towards fewer superficial SSIs in the single high dose group with infection rates of 18.9% (14/74) vs. 30.6% (22/72) (P= 0.05). Diabetes mellitus (odds ratio = 7.04) and surgery duration of longer than 3h (odds ratio = 5.46) were independent risk factors for the development of SSIs. A subset analysis of prolonged operations found significantly fewer superficial SSIs in the single high dose group than in the multiple standard dose group with rates of 22.2% (6/27) vs. 55% (11/20), respectively (P= 0.021). Single high dose gentamicin plus metronidazole preoperatively was at least as effective as the multiple standard dose regimen and may be more effective for prolonged operations.

Laparoscopic surgery and surgical infection

INTRODUCTION

It has been observed that the metabolic response to surgical injury is less after laparoscopic surgery than after open surgery. However, the effect of laparoscopic surgery on surgical infection has not been given much attention in the surgical literature, even though it may decrease the incidence of infectious complications. The objective of this study was to assess the influence that laparoscopic surgery has on surgical infection and to highlight certain controversial aspects.

METHODS

A review of the literature was undertaken to examine the relationship between laparoscopic surgery and surgical infection. This was achieved primarily by using PubMed Medline as a source of material.

RESULTS AND CONCLUSION

Laparoscopic surgery is associated with better preservation of the immune system than open surgery. This results in a decreased incidence of infectious complications. Although carbon dioxide pneumoperitoneum affects the peritoneal response to injury, it seems to have no harmful effect in terms of intra-abdominal infection. Nevertheless, at laparoscopic operation the virulence of intestinal micro-organisms should be recognized and, while knowing the advantages of minimally invasive surgery, the surgeon should consider the complexity of this technique. Furthermore, maintenance of laparoscopic instruments should be governed by the same norms as those used in open surgery; recommendations offered by the manufacturers should be respected.

Epidemiology and microbiology of surgical wound infections

This study included 676 surgery patients with signs and symptoms indicative of wound infections, who presented over the course of 6 years. Bacterial pathogens were isolated from 614 individuals. A single etiologic agent was identified in 271 patients, multiple agents were found in 343, and no agent was identified in 62. A high preponderance of aerobic bacteria was observed. Among the common pathogens were Staphylococcus aureus (191 patients, 28.2%), Pseudomonas aeruginosa (170 patients, 25.2%), Escherichia coli (53 patients, 7.8%), Staphylococcus epidermidis (48 patients, 7.1%), and Enterococcus faecalis (38 patients, 5.6%).

Short-term prophylaxis in clean-contaminated surgery

Postoperative infections are not consistently controlled by current practice measures. From a recent study of 12,384 patients, postoperative infection occurred in 22% of colorectal procedures and 25% of upper gastrointestinal procedures. Infections were associated with a higher death rate, longer hospitalization, and more intense post-discharge care. Control of infections for clean-contaminated procedures requires effective bowel cleansing when appropriate, meticulous surgical technique, and timely antimicrobial administration. Many patients undergoing clean-contaminated surgery do not receive properly timed antimicrobials. Although the comparative value of oral (neomycin and erythromycin) or parenteral antimicrobials for colon surgery remains an unresolved issue, the combination can be beneficial for many colorectal operations. Third generation cephalosporins are not consistently more effective than older agents such as cefoxitin and increase bacterial resistance. Improper antimicrobial timing is one of the most common problems with surgical prophylaxis and is fully under the control of the surgeon. To maximize benefits of antimicrobial prophylaxis, systems should be devised to assure timely administration.