Antibiotic prophylaxis in colorectal surgery

Is There an Association between Intra-Operative Detection of Pathogens in Subcutaneous Tissue and Surgical Site Infections? Results from a Prospective Study

Background: Surgical site infections (SSIs) are a common complication in visceral surgery. Pathogens causing SSIs vary depending on the type of surgery. Patients and Methods: Within the scope of the Reduction of Postoperative Wound Infections by Antiseptica (RECIPE) trial we analyzed the pathogens cultured in intra-operative, subcutaneous swabs and in swabs from SSI in a single-center, prospective, randomized controlled study. Definition of SSI complied with the criteria of the U.S. Centers for Disease Control and Prevention (CDC). Results: The overall rate of SSI was 28.2% in 393 patients. Colorectal surgery was performed in 68.2% of elective laparotomies. Pathogens were more often detected in intra-operative subcutaneous swabs in patients who developed SSIs than in patients who did not develop SSIs (64.4% vs. 38.0%; p < 0.001). Enterococci were found in 29.1% of intra-operative swabs in patients with SSIs, followed by Escherichia coli in 15.5%. A higher rate of Enterococcus faecium was found in patients with anemia versus those without anemia (9.2% vs. 2.3%; p = 0.006) and in patients who smoked versus those who did not (11.8% vs. 3.6%; p = 0.008). A positive subcutaneous swab (odds ratio [OR], 2.51; 95% confidence interval [CI], 1.47-4.29; p = 0.001), pre-operative anemia (OR, 1.84; 95% CI, 1.08-3.13; p = 0.016), and renal insufficiency (OR, 2.15; 95% CI, 1.01-4.59; p = 0.048) were risk factors for SSIs. Conclusions: There is an association between the intra-operative detection of pathogens in subcutaneous tissue and the development of SSIs in visceral surgery. The most prevalent pathogens causing SSIs were enterococci and Escherichia coli. More efforts are justified to reduce subcutaneous colonization with pathogens, for example by using intra-operative wound irrigation with polyhexanide solution. This trial is registered at www.ClinicalTrials.gov (ID: NCT04055233).

A Pilot Randomised Clinical Trial Comparing a Short-Term Perioperative Prophylaxis Regimen to a Long-Term Standard Protocol in Equine Colic Surgery

Background: For surgical interventions classified as clean or clean-contaminated, including laparotomy, guidelines in human and veterinary medicine recommend a short-term perioperative antibiotic prophylaxis (PAP). In equine colic surgery, however, PAP commonly exceeds 24 h. Objectives: The aim of this study was to compare a single-shot to a 5-day lasting PAP considering surgical site infections (SSI) and other adverse effects probably associated with the particular antimicrobial regimen. Study design: The study was designed as a randomised non-inferiority pilot study including horses subjected to colic surgery while receiving one of two distinct PAP regimens. Methods: All horses (n = 67) included in the study received the standard physical examination before and after surgery. Colic surgery was performed according to the current standard of the clinic. Horses were randomly assigned to two groups, receiving either the “single-shot” or the “5-day lasting” antibiotic prophylaxis. The “single-shot” group (n = 30) received penicillin and gentamicin only once before and, if needed, during surgery, whereas the “5-day lasting” group (n = 37) received antibiotics for five days. In addition to the standard laboratory examinations, serum amyloid A and fibrinogen were determined preoperatively and during five days after surgery. SSI, postoperative colitis and haemolytic anaemia were classified as postoperative complications potentially related to antibiotic use. Results: The outcome of this preliminary non-inferiority clinical trial showed that the occurrence of postoperative adverse events (i.e., SSI, postoperative colitis and haemolytic anaemia) lacked significant differences between the study groups. Main limitations: The main limitations of this study are the limited group sizes and our inability to blind the study. Conclusions: Single-shot PAP seems to be an alternative approach considering the 5-day lasting protocol commonly used in equine abdominal surgery. However, a proper hygiene management together with a close clinical and laboratory monitoring of the equine patient is indispensable.

Intraoperative modifiable risk factors of colorectal anastomotic leakage: Why surgeons and anesthesiologists should act together

BACKGROUND

Colorectal anastomotic leakage (CAL) is a major surgical complication in intestinal surgery. Despite many optimizations in patient care, the incidence of CAL is stable (3-19%) [1]. Previous research mainly focused on determining patient and surgery related risk factors. Intraoperative non-surgery related risk factors for anastomotic healing also contribute to surgical outcome. This review offers an overview of potential modifiable risk factors that may play a role during the operation.

METHODS

Two independent literature searches were performed using EMBASE, Pubmed and Cochrane databases. Both clinical and experimental studies published in English from 1985 to August 2015 were included. The main outcome measure was the risk of anastomotic leakage and other postoperative complications during colorectal surgery. Determined risk factors of CAL were stated as strong evidence (level I and II high quality studies), and potential risk factors as either moderate evidence (experimental studies level III), or weak evidence (level IV or V studies).

RESULTS

The final analysis included 117 articles. Independent factors of CAL are diabetes mellitus, hyperglycemia and a high HbA1c, anemia, blood loss, blood transfusions, prolonged operating time, intraoperative events and contamination and a lack of antibiotics. Unequivocal are data on blood pressure, the use of inotropes/vasopressors, oxygen suppletion, type of analgesia and goal directed fluid therapy. No studies could be found identifying the impact of body core temperature or mean arterial pressure on CAL. Subjective factors such as the surgeons' own assessment of local perfusion and visibility of the operating field have not been the subject of relevant studies for occurrence in patients with CAL.

CONCLUSION

Both surgery related and non-surgery related risk factors that can be modified must be identified to improve colorectal care. Surgeons and anesthesiologists should cooperate on these items in their continuous effort to reduce the number of CAL. A registration study determining individual intraoperative risk factors of CAL is currently performed as a multicenter cohort study in the Netherlands.

Pharmacokinetic and Pharmacodynamic Evaluation of a Weight-Based Dosing Regimen of Cefoxitin for Perioperative Surgical Prophylaxis in Obese and Morbidly Obese Patients

The objective of this study was to determine the pharmacokinetics and pharmacodynamics (PK/PD) of a weight-based cefoxitin dosing regimen for surgical prophylaxis in obese patients. Patients received a single dose of cefoxitin at 40 mg/kg based on total body weight. Cefoxitin samples were obtained over 3 h from serum and adipose tissue, and concentrations were determined by validated high-performance liquid chromatography. Noncompartmental pharmacokinetic analysis was performed, followed by Monte Carlo simulations to estimate probability of target attainment (PTA) for Staphylococcus aureus, Escherichia coli, and Bacteroides fragilis over 4-h periods postdose. Thirty patients undergoing bariatric procedures were enrolled. The body mass index (mean ± standard deviation [SD])was 45.9 ± 8.0 kg/m(2) (range, 35.0 to 76.7 kg/m(2)); the median cefoxitin dose was 5 g (range, 4.0 to 7.5 g). The mean maximum concentrations were 216.15 ± 41.80 μg/ml in serum and 12.62 ± 5.89 in tissue; the mean tissue/serum ratio was 8% ± 3%. In serum, weight-based regimens achieved ≥90% PTA (goal time during which free [unbound] drug concentrations exceed pathogen MICs [fT>MIC] of 100%) for E. coli and S. aureus over 2 h and for B. fragilis over 1 h; in tissue this regimen failed to achieve goal PTA at any time point. The 40-mg/kg regimens achieved higher PTAs over longer periods in both serum and tissue than did the standard 2-g doses. However, although weight-based cefoxitin regimens were better than fixed doses, achievement of desired pharmacodynamic targets was suboptimal in both serum and tissue. Alternative dosing regimens and agents should be explored in order to achieve more favorable antibiotic performance during surgical prophylaxis in obese patients.

Perioperative Antibiotic Prophylaxis and Antimicrobial Therapy of Intra-Abdominal Infections

Background

The increase of antimicrobial resistances to first- and second-line antibiotics, especially of Gram-negative bacteria, and the lack of novel antimicrobial substances are a challenge in the treatment of intra-abdominal infections.

Methods

Review article.

Results

The efficacy and safety of perioperative antibiotic prophylaxis in visceral surgery has been demonstrated by several meta-analyses. Perioperative antibiotic prophylaxis is defined as a single administration of antibiotics shortly before a surgical intervention. A so-called prolonged prophylaxis including the postoperative period (e.g. 1-3 days postoperatively) should be avoided as it does not reduce the number of wound infections and is associated with an increased risk of antimicrobial resistance and side effects. Antimicrobial management of severe intra-abdominal infections involves a delicate balance of optimizing empirical therapy which has been shown to improve outcomes while simultaneously reducing unnecessary use of antimicrobials.

Conclusion

Antimicrobial resistance poses a serious threat to human health and requires a rational use of antibiotics to curb further spreading. This applies for perioperative prophylaxis as well as for the treatment of intra-abdominal infections.

Subcutaneous application of gentamicin collagen implants as prophylaxis of surgical site infections in laparoscopic colorectal surgery: a randomized, double-blinded, three-arm trial

PURPOSE

Despite a standardized prophylaxis with antibiotics, surgical site infections (SSI) are a characteristic problem in colorectal surgery. Local administration of gentamicin-collagen sponges (GCS) has been shown to decrease the infection rate after contaminated procedures. So far, the effect has not been tested for standardized laparoscopic colorectal resections.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial to investigate the efficacy of GCS to reduce wound infection after laparoscopic colorectal resections. Patients underwent a standardized operative procedure with standardized incision treatment. The intervention was the application of a GCS in the subcutaneous tissue of the bowel extraction site (GCS group). In the collagen group, a collagen sponge without antibiotics was used, and no sponge was used in the control group. The primary endpoint was SSI within 30 days postoperatively, according to the Center of Disease Control and Prevention definition.

RESULTS

We randomly assigned 291 patients to all three groups. There was no difference between the groups regarding demographic characteristics and perioperative course. SSI was diagnosed in 8.2 % (GCS group), 13.5 % (collagen group), and 11.3 % (control group) of patients. No significant difference was found among the groups.

CONCLUSION

The local administration of GCS showed no significant benefit regarding wound infection after standardized laparoscopic colorectal resections. However, there was a trend toward reduced SSI in the GCS group. Therefore, a larger trial or meta-analysis is necessary to validate this result.

[Antibiotic prophylaxis in urology]

The aim of perioperative antibiotic prophylaxis is the prevention of surgical site infections and urinary tract infections during urological procedures. The indication for antibiotic prophylaxis comprises several risk factors such as the degree of contamination of the operative site, duration of surgery, implantation of devices and comorbidities of the individual patient. In general this involves a single antibiotic administration before the operative procedure. The antibiotic prophylaxis is part of the total antibiotic consumption and thus a factor contributing to emergence of antibiotic resistance. It is not a substitute for hygiene measures or operative precision.

[Evidence-based antibiotic prophylaxis in general and visceral surgery]

The use of prophylactic perioperative antibiotic therapy if indicated could successfully and safely prevent surgical wound infections. The current guidelines (S1) for prophylactic perioperative antibiotic therapy of the Study Group of the Scientific Medical Associations (AWMF) of 2004 was replaced by a recommendation of the study group of the Paul-Ehrlich-Gesellschaft for Chemotherapy (PEG) in 2010. This recommendation includes recent research data from 2000 to 2008. Indications and choice of antibiotic agent depend on specific risk factors of the patient and the operation performed. The aim of this article is to describe the current recommendations of the PEG for general and visceral surgery.

Antimicrobial prophylaxis in colorectal surgery: focus on ertapenem

Despite improvement in infection control measures and surgical practice, surgical site infections (SSIs) remain a major cause of morbidity and mortality. In colorectal surgery, perioperative administration of a suitable antimicrobial regimen that covers both anaerobic and aerobic bacteria is universally accepted. In a prospective, double-blind, randomized study ertapenem was recently found to be more effective than cefotetan, a parenteral cephalosporin so broadly used as to be considered as gold standard in the prevention of SSIs following colorectal surgery. In this adequate and well controlled study, the superiority of ertapenem over cefotetan was clearly demonstrated from the clinical and bacteriological points of view. However, data that directly compares ertapenem with other antimicrobial regimen effective in preventing SSIs following colorectal surgery are lacking; furthermore, the possible risk of promotion of carbapenem resistance associated with widespread use of ertapenem prophylaxis as well as the ertapenem effects on the intestinal gut flora are of concern. Further comparative studies of ertapenem versus other widely used prophylactic regimens for colorectal surgery in patients submitted to mechanical bowel preparation versus no preparation as well as further research on adverse events of antibiotic prophylaxis, including emergence of resistance and Clostridium difficile infection, seem warranted.

Infection after elective colorectal surgery: bacteriological analysis of failures in a randomized trial of cefotetan vs. ertapenem prophylaxis

BACKGROUND

A randomized study comparing single-dose cefotetan and ertapenem prophylaxis for elective colorectal surgery in 1,002 patients found ertapenem to be significantly more effective (p < 0.001). Failures of prophylaxis were thought to involve organisms resistant to both antimicrobial agents, isolated most often from deep or superficial incision sites.

METHODS

Further testing and analysis of the microbial data was performed. Susceptibility results were correlated with the clinical outcomes reported previously.

RESULTS

Of the 216 aerobes tested, 62.6% were resistant to cefotetan and 44% to ertapenem. Enterococci and methicillin-resistant Staphylococcus epidermidis were the aerobes recovered most frequently, and Bacteroides thetaiotaomicron, Clostridium innocuum, and Eubacterium lentum were the most frequent anaerobes. Enterococcus faecalis usually was associated in mixed culture with Bacteroides fragilis group species. Approximately one-half of the 158 anaerobes (50.7%), including all the species above, were resistant to cefotetan; most of these (61.4%) came from superficial incision sites. Only one anaerobe (Desulfovibrio fairfieldensis), found in a superficial incisional infection, was resistant to ertapenem, and no ertapenem-resistant enteric bacteria were recovered. In vitro resistance was associated with therapeutic failure.

CONCLUSIONS

The in vitro activity of ertapenem was superior to that of cefotetan against all anaerobic and many aerobic bacteria isolated from postoperative cultures of patients who failed prophylaxis with these agents. Our findings help to elucidate the results of the clinical trial.