Local antibiotic decontamination to prevent anastomotic leakage short-term outcome in rectal cancer surgery

Successful Clinical Avoidance of Colorectal Anastomotic Leakage through Local Decontamination

AIM

An anastomotic leak is an unpredictable postoperative complication during recovery from colorectal surgery that may require a re-operation. Potentially pathogenic bacteria like Pseudomonas (and Enterococcus) contribute to the pathogenesis of an anastomotic leak through their capacity to degrade collagen and to activate tissue matrix metalloprotease-9 in host intestinal tissues. The microbiome, therefore, is the key to preventing an anastomotic leak after colorectal surgery. The aim of this trial was to investigate whether perioperative selective decontamination with a new mixture of locally acting antibiotics specially designed against Pseudomonas aeruginosa and Enterococcus faecalis can reduce or even stop early symptomatic leakage.

METHOD

All hospitalized patients in our University Clinic undergoing colorectal surgery with a left-sided anastomosis were included as two groups; patients in the intervention group received polymyxin B, gentamicin and vancomycin every six hours for five postoperative days and those in the control group did not receive such an intervention. An anastomotic leak was defined as a clinically obvious defect of the intestinal wall integrity at the colorectal anastomosis site (including suture) that leads to a communication between the intra- and extraluminal compartments, requiring a re-do surgery within seven postoperative days.

RESULTS

Between February 2017 and May 2023, a total of 301 patients (median age of 63 years) were analyzed. An anastomotic leak was observed in 11 patients in the control group (n = 152), but in no patients in the intervention group (n = 149); this difference was highly significant.

CONCLUSION

The antibiotic mixture (with polymyxin B, gentamicin and vancomycin) used for local decontamination in our study stopped the occurrence of anastomotic leaks completely. According to the definition of anastomotic leak, no further surgery was required after local perioperative decontamination.

The Influence of the Microbiome on Anastomotic Leak

Anastomotic leak, defined by the International Study Group of Rectal Cancer as "a communication between the intra- and extraluminal compartments owing to a defect of the integrity of the intestinal wall at the anastomosis," is one of the most devastating complications in colorectal surgery. Much work has been done to identify causes of leak; however, despite advances in surgical technique, the prevalence of anastomotic leak has remained at around 11%. The potential causative role of bacteria in the etiopathology of anastomotic leak was established in the 1950s. More recently, alterations in the colonic microbiome have been shown to affect rates of anastomotic leak. Multiple perioperative factors that alter the homeostasis of the gut microbiota community structure and function have been linked to anastomotic leak after colorectal surgery. Here, we discuss the role of diet, radiation, bowel preparation, medications including nonsteroidal anti-inflammatory drugs, morphine, and antibiotics, and specific microbial pathways that have been implicated in anastomotic leak via their effects on the microbiome.

Anastomotic leakage in rectal cancer surgery: Retrospective analysis of risk factors

BACKGROUND

Anastomotic leakage (AL) after restorative surgery for rectal cancer (RC) is associated with significant morbidity and mortality.

AIM

To ascertain the risk factors by examining cases of AL in rectal surgery in this retrospective cohort study.

METHODS

To identify risk factors for AL, a review of 583 patients who underwent rectal resection with a double-stapling colorectal anastomosis between January 2007 and January 2022 was performed. Clinical, demographic and operative features, intraoperative outcomes and oncological characteristics were evaluated.

RESULTS

The incidence of AL was 10.4%, with a mean time interval of 6.2 ± 2.1 d. Overall mortality was 0.8%. Mortality was higher in patients with AL (4.9%) than in patients without leak (0.4%, P = 0.009). Poor bowel preparation, blood transfusion, median age, prognostic nutritional index < 40 points, tumor diameter and intraoperative blood loss were identified as risk factors for AL. Location of anastomosis, number of stapler cartridges used to divide the rectum, diameter of circular stapler, level of vascular section, T and N status and stage of disease were also correlated to AL in our patients. The diverting ileostomy did not reduce the leak rate, while the use of the transanastomic tube significantly did.

CONCLUSION

Clinical, surgical and pathological factors are associated with an increased risk of AL. It adversely affects the morbidity and mortality of RC patients.

Antibiotic Bowel Decontamination in Gastrointestinal Surgery—A Single-Center 20 Years’ Experience

Objective

Anastomotic leakage, surgical site infections, and other infectious complications are still common complications in gastrointestinal surgery. The concept of perioperative antibiotic bowel decontamination demonstrates beneficial effects in single randomized controlled trials (RCTs), but data from routine clinical use are still sparse. Our aim was to analyze the data from the routine clinical use of perioperative antibiotic bowel decontamination in gastrointestinal surgery.

Methods

Based on 20 years’ experience, we performed a retrospective analysis of all cases in oncologic gastrointestinal surgery with the use of antibiotic bowel decontamination in gastric, sigmoid, and rectal cancer. Clinical data and perioperative outcomes were analyzed, especially regarding anastomotic leakage, surgical site infections, and other infectious complications.

Results

A total of n = 477 cases of gastrointestinal surgery in gastric cancer (n = 80), sigmoid cancer (n = 168), and rectal cancer (n = 229) using a perioperative regimen of antibiotic bowel decontamination could be included in this analysis. Overall, anastomotic leakage occurred in 4.4% (2.5% gastric cancer, 3.0% sigmoid cancer, 6.1% rectal cancer) and surgical site infections in 9.6% (6.3% gastric cancer, 9.5% sigmoid cancer, 10.9% rectal cancer). The incidence of all infectious complications was 13.6% (12.5% gastric cancer, 11.3% sigmoid cancer, 15.7% rectal cancer). Mortality was low, with an overall rate of 1.1% (1.3% gastric cancer, 1.8% sigmoid cancer, 0.4% rectal cancer). Antibiotic decontamination was completed in 98.5%. No adverse effects of antibiotic bowel decontamination could be observed.

Conclusion

Overall, in this large cohort, we can report low rates of surgery-related serious morbidity and mortality when perioperative antibiotic bowel decontamination is performed. The rates are lower than other clinical reports. In our clinical experience, the use of perioperative antibiotic bowel decontamination appears to improve patient safety and surgical outcomes during gastrointestinal oncologic procedures in a routine clinical setting.

Anastomotic leakage in colorectal cancer surgery

The safety of colorectal surgery for oncological disease is steadily improving, but anastomotic leakage is still the most feared and devastating complication from both a surgical and oncological point of view. Anastomotic leakage affects the outcome of the surgery, increases the times and costs of hospitalization, and worsens the prognosis in terms of short- and long-term outcomes. Anastomotic leakage has a wide range of clinical features ranging from radiological only finding to peritonitis and sepsis with multi-organ failure. C-reactive protein and procalcitonin have been identified as early predictors of anastomotic leakage starting from postoperative day 2-3, but abdominal-pelvic computed tomography scan is still the gold standard for the diagnosis. Several treatments can be adopted for anastomotic leakage. However, there is not a universally accepted flowchart for the management, which should be individualized based on patient's general condition, anastomotic defect size and location, indication for primary resection and presence of the proximal stoma. Non-operative management is usually preferred in patients who underwent proximal faecal diversion at the initial operation. Laparoscopy can be attempted after minimal invasive surgery and can reduce surgical stress in patients allowing a definitive treatment. Reoperation for sepsis control is rarely necessary in those patients who already have a diverting stoma at the time of the leak, especially in extraperitoneal anastomoses. In patients without a stoma who do not require abdominal reoperation for a contained pelvic leak, there are several treatment options, including laparoscopic diverting ileostomy combined with trans-anal anastomotic tube drainage, percutaneous drainage or recently developed endoscopic procedures, such as stent or clip placement or endoluminal vacuum-assisted therapy. We describe the current approaches to treat this complication, as well as the clinical tests necessary to diagnose and provide an effective therapy.

It is not NOD2 - genetic and clinical risk factors for postoperative complications following ileocolic resection in Crohn's disease

PURPOSE

To evaluate the role of the nucleotide oligomerization domain 2 (NOD2) mutation status and other risk factors for the incidence of postoperative complications after ileocolic resection for Crohn's disease (CD).

METHODS

Data of 138 patients consecutively undergoing ileocolic resection for CD at a tertiary academic referral center were retrospectively analyzed including single nucleotide polymorphism (SNP) data of the NOD2 gene. Uni- and multivariate regression analysis was performed to identify factors associated with increased risk of severe postoperative complications.

RESULTS

From 114 patients (83%), the NOD2 mutation status was available. Of these, 60 (53%) had a NOD2 wildtype, whereas eleven (10%) were homozygous for the high risk p.Leu1007fsX1008 (rs2066847) variant. Major postoperative complications occurred in 28 patients (20%). Twenty-seven of these (96%) were intraabdominal septic complications such as anastomotic leakage or abscess. Male gender (P = 0.029; OR 3.052, the duration of CD (time [months] from initial diagnosis of CD to surgery; P = 0.001; OR 1.009), previous abdominal surgery for CD (P = 0.017; OR 3.49), and the presence of enteric fistulas (P = 0.023; OR 3.21) were identified as independent risk factors for major postoperative complications. Homozygosity for the NOD2 high-risk variant p.Leu1007fsX1008 did not show increased postoperative morbidity in the short and long-term outcome.

CONCLUSIONS

We could detect independent risk factors for major postoperative complications after ileocolic resection for Crohn's disease. However, patients with the high-risk variant p.Leu1007fsX1008 of the NOD2 gene did not show increased postoperative morbidity.

Influence of the Microbiome on Anastomotic Leak

Despite advances in surgical technique and the expanded use of antibiotics, anastomotic leak remains a dreaded complication leading to increased hospital length of stay, morbidity, mortality, and cost. Data continues to grow addressing the importance of a functional and diverse colonic microbiome to ensure adequate healing. Individual pathogens, such as Enterococcus faecalis and Pseudomonas aeruginosa , have been implicated in the pathogenesis of anastomotic leak. Yet how these pathogens proliferate remains unclear. It is possible that decreased microbial diversity promotes a shift to a pathologic phenotype among the remaining microbiota which may lead to anastomotic breakdown. As the microbiome is highly influenced by diet, antibiotic use, the stress of surgery, and opioid use, these factors may be modifiable at various phases of the surgical process. A large amount of data remains unknown about the composition and behavior of the "normal" gut microbiome as compared with an altered community. Therefore, targeting the gut microbiome as a modifiable factor in anastomotic healing may represent a novel strategy for the prevention of anastomotic leak.

Selective Intestinal Decontamination as a Method for Preventing Infectious Complications (Review)

Infectious complications are the most common cause of death in patients with severe burns. To date, there is no generally accepted method for preventing such complications in burn injury. One of the possible prevention options is selective intestinal decontamination (SID). This method is based on the enteral administration of non-absorbable antimicrobial agents. The preventive effect of SID involves inhibition of intestinal microflora translocation through the mucous membranes, inasmuch as studies demonstrate that endogenous opportunistic microorganisms are a common cause of infectious complications in various critical conditions.

The SID method was originally developed in the Netherlands for patients suffering from mechanical injury. Antimicrobial drugs were selected based on their high activity in relation to the main endogenous opportunistic pathogens and minimal activity against normal intestinal microflora components. The combination of polymyxin (B or E), tobramycin, and amphotericin B with intravenous cefotaxime was chosen as the first SID regimen. Other regimens were proposed afterwards, and the application field of the method was expanded. In particular, it became the method of choice for prevention of infectious complications in patients with severe burn injury.

Clinical studies demonstrate efficacy of some SID regimens for preventing infectious complications in patients with thermal injury. Concomitant administration of SID and systemic preventive antibiotics and addition of oropharyngeal decontamination increases the method efficacy. SID is generally well-tolerated, but some studies show an increased risk of diarrhea with this preventive option. In addition, SID increases the risk of developing antibiotic resistance like any other antibiotic regimens.

Current Insights: The Impact of Gut Microbiota on Postoperative Complications in Visceral Surgery-A Narrative Review

Postoperative complications are a major problem occurring in up to 50% of patients undergoing major abdominal surgery. Occurrence of postoperative complications is associated with a significantly higher morbidity and mortality in affected patients. The most common postoperative complications are caused by an infectious genesis and include anastomotic leakage in case of gastrointestinal anastomosis and surgical site infections. Recent research highlighted the importance of gut microbiota in health and disease. It is plausible that the gut microbiota also plays a pivotal role in the development of postoperative complications. This narrative review critically summarizes results of recent research in this particular field. The review evaluates the role of gut microbiota alteration in postoperative complications, including postoperative ileus, anastomotic leakage, and surgical site infections in visceral surgery. We tried to put a special focus on a potential diagnostic value of pre- and post-operative gut microbiota sampling showing that recent data are inhomogeneous to identify a high-risk microbial profile for development of postoperative complications.

Anastomotic Leak: Toward an Understanding of Its Root Causes

BACKGROUND

When an anastomotic leak is discussed at a typical surgical morbidity and mortality conference, it is often presented as a due to an error in surgical technique involving ischemia, tension, or device failure. Here we assert that without direct visual analysis of the leak site and its tissue histology, an ex post facto claim that an anastomotic leak is due to an error in surgical technique remains speculative.

METHODS

The arguments and rationale used to conclude that an anastomotic leak is due to an error in surgical technique are critically reviewed and assessed for their validity.

RESULTS

No case series or literature exists in which a root cause analysis has been carried out with visual and tissue level evidence to determine the root cause(s) of an anastomotic leak.

CONCLUSIONS

At the individual case level, declaring that an anastomotic leak is due to an error in surgical technique without clear and compelling evidence either visually and/or at the tissue level to substantiate such a claim remains speculative.

The gut microbiota and colorectal surgery outcomes: facts or hype? A narrative review

BACKGROUND

The gut microbiota (GM) has been proposed as one of the main determinants of colorectal surgery complications and theorized as the "missing factor" that could explain still poorly understood complications. Herein, we investigate this theory and report the current evidence on the role of the GM in colorectal surgery.

METHODS

We first present the findings associating the role of the GM with the physiological response to surgery. Second, the change in GM composition during and after surgery and its association with colorectal surgery complications (ileus, adhesions, surgical-site infections, anastomotic leak, and diversion colitis) are reviewed. Finally, we present the findings linking GM science to the application of the enhanced recovery after surgery (ERAS) protocol, for the use of oral antibiotics with mechanical bowel preparation and for the administration of probiotics/synbiotics.

RESULTS

According to preclinical and translational evidence, the GM is capable of influencing colorectal surgery outcomes. Clinical evidence supports the application of an ERAS protocol and the preoperative administration of multistrain probiotics/synbiotics. GM manipulation with oral antibiotics with mechanical bowel preparation still has uncertain benefits in right-sided colic resection but is very promising for left-sided colic resection.

CONCLUSIONS

The GM may be a determinant of colorectal surgery outcomes. There is an emerging need to implement translational research on the topic. Future clinical studies should clarify the composition of preoperative and postoperative GM and the impact of the GM on different colorectal surgery complications and should assess the validity of GM-targeted measures in effectively reducing complications for all colorectal surgery locations.

Reinforcement of Colonic Anastomosis with Improved Ultrafine Nanofibrous Patch: Experiment on Pig

Anastomotic leakage is a dreadful complication in colorectal surgery. It has a negative impact on postoperative mortality, long term life quality and oncological results. Nanofibrous polycaprolactone materials have shown pro-healing properties in various applications before. Our team developed several versions of these for healing support of colorectal anastomoses with promising results in previous years. In this study, we developed highly porous biocompatible polycaprolactone nanofibrous patches. We constructed a defective anastomosis on the large intestine of 16 pigs, covered the anastomoses with the patch in 8 animals (Experimental group) and left the rest uncovered (Control group). After 21 days of observation we evaluated postoperative changes, signs of leakage and other complications. The samples were assessed histologically according to standardized protocols. The material was easy to work with. All animals survived with no major complication. There were no differences in intestinal wall integrity between the groups and there were no signs of anastomotic leakage in any animal. The levels of collagen were significantly higher in the Experimental group, which we consider to be an indirect sign of higher mechanical strength. The material shall be further perfected in the future and possibly combined with active molecules to specifically influence the healing process.

Oral antibiotic bowel decontamination in open and laparoscopic sigmoid resections for diverticular disease

PURPOSE

There is an ongoing debate on whether or not to use oral antibiotic bowel decontamination in colorectal surgery, despite the numerous different regimens in terms of antibiotic substances and duration of application. As we routinely use oral antibiotic bowel decontamination (selective decontamination of the digestive tract (SDD) regimen and SDD regimen plus vancomycin since 2016) in surgery for diverticular disease, our aim was to retrospectively analyze the perioperative outcome in two independent centers.

METHODS

Data from two centers with a routine use of oral antibiotic bowel decontamination for up to 20 years of experience were analyzed for the perioperative outcome of 384 patients undergoing surgery for diverticular disease.

RESULTS

Overall morbidity was 12.8%, overall mortality was 0.3%, the overall rate of anastomotic leakage (AL) was 1.0%, and surgical site infections (SSIs) were 5.5% and 7.8% of all infectious complications including urinary tract infections and pneumonia. No serious adverse events were related to use of oral antibiotic bowel decontamination. Most of the patients (93.8%) completed the perioperative regimen. Additional use of vancomycin to the SDD regimen did not show a further reduction of infectious complications, including SSI and AL.

CONCLUSION

Oral antibiotic decontamination appears to be safe and effective with low rates of AL and infectious complications in surgery for diverticular disease.

Prevention of anastomotic leak in rectal cancer surgery with local antibiotic decontamination: a prospective, randomized, double-blind, placebo-controlled single center trial

PURPOSE

Anastomotic leak and other infectious complications are septic complications of rectal cancer surgery caused by bacteria. Data from registry analysis show a beneficial effect of local antimicrobial administration on anastomotic leaks, but data are inconsistent in recent clinical trials. Therefore, our aim was to study the efficacy of topical antibiotic treatment on the incidence of anastomotic leaks in rectal cancer surgery.

METHODS

A prospective, randomized, double-blind and placebo-controlled, single center trial was conducted. Patients received either placebo and amphotericin B or decontamination with polymyxin B, tobramycin, vancomycin, and amphotericin B four times per day starting the day before surgery until postoperative day 7. If a protective ileostomy was created, a catheter was placed transanally and the medication was administered locally to the anastomotic site. All patients received an intravenous perioperative antibiotic prophylaxis.

RESULTS

The trial had to be stopped for ethical reasons after first interim analysis with 80 patients instead of the initially planned 280 patients. Of the 40 patients randomized to receive placebo, eight (20%) developed anastomotic leak compared to only 2 (5%) in the treatment group of 40 patients (decontamination) with significant difference in the χ² test (p = 0.0425). Twenty percent of the placebo group and 12.5% in the treatment group developed infectious complications not associated with anastomotic leak (p = 0.5312). One patient (2.5%) in the placebo group died (p = 0.3141).

CONCLUSION

Local decontamination with polymyxin, tobramycin, vancomycin, and amphotericin B is safe and effective in the prevention of anastomotic leak in rectal cancer surgery.

Involvement of the Commensal Organism Bacillus subtilis in the Pathogenesis of Anastomotic Leak

Background: It is now well established that microbes play a key and causative role in the pathogenesis of anastomotic leak. Yet, in patients, determining whether a cultured pathogen retrieved from an anastomotic leak site is a cause or a consequence of the complication remains a challenge. The aim of this study was to test a methodology to invoke causality between a retrieved microbe from a leak site and its role in anastomotic leak. Methods: The commensal organism Bacillus subtilis was isolated from an esophagojejunostomy leak site in a 35-year-old patient with a CDH1 mutation after a prophylactic gastrectomy whose body mass index (BMI) was 35 kg/m². The organism was screened for its ability to degrade collagen, shift human recombinant matrix metalloprotease-9 (MMP9) to its active form, and induce a clinical anastomotic leak when introduced to anastomotic tissues of mice fed their standard diet (SD) of chow or an obesogenic Western-type diet (WD). Results: The Bacillus subtilis strain retrieved from the anastomotic leak site displayed a high degree of collagenolytic activity and was able to activate human MMP9 consistent with other pathogens expressing this characteristic "leak phenotype." Exposure of the Bacillus subtilis to the anastomotic tissues of obese mice fed a WD led to dehiscence of the anastomosis, abscess formation with peritonitis, and mortality in 50% of mice (3/6). When anastomotic healing was evaluated by a validated anastomotic healing score (AHS), substantially worse healing was observed (i.e., higher AHS) in WD-fed mice exposed to Bacillus subtilis compared to SD-fed mice (analysis of variance [ANOVA], p = 0.0006). Conclusions: Microbial strains obtained from patients' anastomotic leak sites can be evaluated for their pathogenic in the leak process by assessing their ability to produce collagenase, activate MMP9 and cause clinical leaks in mice fed a WD. These studies may aid in identifying those bacterial strains that play a causal role in patients with an anastomotic leak.

[Oral antibiotic prophylaxis for bowel decontamination before elective colorectal surgery : Current body of evidence and recommendations]

Despite a growing body of evidence from randomized controlled studies, register data and meta-analyses, there is an ongoing controversy about decontamination of the digestive tract before elective colorectal surgery. Currently, mechanical bowel preparation alone can no longer be recommended as there is a lack of evidence for an advantage in terms of risk reduction for infectious complications, anastomotic leakage, morbidity and mortality. In contrast, the administration of oral antibiotics in addition to the obligatory intravenous single shot antibiotic prophylaxis has shown an additive reduction of the risk of up to 50% for the occurrence of postoperative infectious complications; however, due to a lack of data it is unclear if mechanical bowel preparation could even improve the positive effects of combined intravenous and oral antibiotics. Therefore, further studies are necessary. At the current time the occurrence of anastomotic leakage cannot be prevented, independent of whether preoperative bowel decontamination is performed.