A trial of mezlocillin versus cefuroxime with or without metronidazole for the prevention of wound sepsis after biliary and gastrointestinal surgery

Antibiotics in the Biliary Tract: A Review of the Pharmacokinetics and Clinical Outcomes of Antibiotics Penetrating the Bile and Gallbladder Wall

Biliary tract infections (BTIs), including cholangitis and cholecystitis, are common causes of bacteremia. Bacteremic BTIs are associated with a mortality rate of 9-12%. The extent to which antibiotics are excreted in the bile and the ratio of their exposure to the minimum inhibitory concentration of the infecting organism are among the important factors for the treatment of BTIs. This review updates health care professionals on the distribution of antibiotics in the common bile duct, gallbladder, and gallbladder wall. Antibiotic efficacy in treating BTIs based on the latest available clinical studies is also discussed. The efficacy and pharmacokinetics of 50 antibiotics are discussed. Overall, most antibiotic classes exhibit biliary penetration that translates into clinical efficacy. Only seven antibiotics (amoxicillin, cefadroxil, cefoxitin, ertapenem, gentamicin, amikacin, and trimethoprim/sulfamethoxazole) had poor biliary penetration profiles. Three antibiotics (ceftibuten, ceftolozane/tazobactam, and doripenem) had positive clinical outcomes despite the lack of pharmacokinetic studies on their penetration into the biliary tract. Conflicting efficacy data were reported for ampicillin despite adequate biliary penetration, whereas conflicting pharmacokinetic data were reported with cefaclor and moxifloxacin. Even in the absence of supportive clinical studies, antibiotics with good biliary penetration profiles may have a place in the treatment of BTIs.

Antimicrobial prophylaxis for colorectal surgery

BACKGROUND

Research shows that administration of prophylactic antibiotics before colorectal surgery prevents postoperative surgical wound infection. The best antibiotic choice, timing of administration and route of administration remain undetermined.

OBJECTIVES

To establish the effectiveness of antimicrobial prophylaxis for the prevention of surgical wound infection in patients undergoing colorectal surgery. Specifically to determine:1. whether antimicrobial prophylaxis reduces the risk of surgical wound infection;2. the target spectrum of bacteria (aerobic or anaerobic bacteria, or both);3. the best timing and duration of antibiotic administration;4. the most effective route of antibiotic administration (intravenous, oral or both);5. whether any antibiotic is clearly more effective than the currently recommended gold standard specified in published guidelines;6. whether antibiotics should be given before or after surgery.

SEARCH METHODS

For the original review published in 2009 we searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE (Ovid) and EMBASE (Ovid). For the update of this review we rewrote the search strategies and extended the search to cover from 1954 for MEDLINE and 1974 for EMBASE up to 7 January 2013. We searched CENTRAL on the same date (Issue 12, 2012).

SELECTION CRITERIA

Randomised controlled trials of prophylactic antibiotic use in elective and emergency colorectal surgery, with surgical wound infection as an outcome.

DATA COLLECTION AND ANALYSIS

Data were abstracted and reviewed by one review author and checked by another only for the single, dichotomous outcome of surgical wound infection. Quality of evidence was assessed using GRADE methods.

MAIN RESULTS

This updated review includes 260 trials and 68 different antibiotics, including 24 cephalosporins and 43,451 participants. Many studies had multiple variables that separated the two study groups; these could not be compared to other studies that tested one antibiotic and had a single variable separating the two groups. We did not consider the risk of bias arising from attrition and lack of blinding of outcome assessors to affect the results for surgical wound infection.Meta-analyses demonstrated a statistically significant difference in postoperative surgical wound infection when prophylactic antibiotics were compared to placebo/no treatment (risk ratio (RR) 0.34, 95% confidence interval (CI) 0.28 to 0.41, high quality evidence). This translates to a reduction in risk from 39% to 13% with prophylactic antibiotics. The slightly higher risk of wound infection with short-term compared with long-term duration antibiotic did not reach statistical significance (RR 1.10, 95% CI 0.93 to 1.30). Similarly risk of would infection was slightly higher with single-dose antibiotics when compared with multiple dose antibiotics, but the results are compatible with benefit and harm (RR 1.30, 95% CI 0.81 to 2.10). Additional aerobic coverage and additional anaerobic coverage both showed statistically significant improvements in surgical wound infection rates (RR 0.44, 95% CI 0.29 to 0.68 and RR 0.47, 95% CI 0.31 to 0.71, respectively), as did combined oral and intravenous antibiotic prophylaxis when compared to intravenous alone (RR 0.56, 95% CI 0.43 to 0.74), or oral alone (RR 0.56, 95% CI 0.40 to 0.76). Comparison of an antibiotic with anaerobic specificity to one with aerobic specificity showed no significant advantage for either one (RR 0.84, 95% CI 0.30 to 2.36). Two small studies compared giving antibiotics before or after surgery and no significant difference in this timing was found (RR 0.67, 95% CI 0.21 to 2.15). Established gold-standard regimens recommended in major guidelines were no less effective than any other antibiotic choice.

AUTHORS' CONCLUSIONS

This review has found high quality evidence that antibiotics covering aerobic and anaerobic bacteria delivered orally or intravenously (or both) prior to elective colorectal surgery reduce the risk of surgical wound infection. Our review shows that antibiotics delivered within this framework can reduce the risk of postoperative surgical wound infection by as much as 75%. It is not known whether oral antibiotics would still have these effects when the colon is not empty. This aspect of antibiotic dosing has not been tested. Further research is required to establish the optimal timing and duration of dosing, and the frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.

Antibiotic prophylaxis for the prevention of methicillin-resistant Staphylococcus aureus (MRSA) related complications in surgical patients

BACKGROUND

Risk of methicillin-resistant Staphylococcus aureus (MRSA) infection after surgery is generally low, but affects up to 33% of patients after certain types of surgery. Postoperative MRSA infection can occur as surgical site infections (SSIs), chest infections, or bloodstream infections (bacteraemia). The incidence of MRSA SSIs varies from 1% to 33% depending upon the type of surgery performed and the carrier status of the individuals concerned. The optimal prophylactic antibiotic regimen for the prevention of MRSA after surgery is not known.

OBJECTIVES

To compare the benefits and harms of all methods of antibiotic prophylaxis in the prevention of postoperative MRSA infection and related complications in people undergoing surgery.

SEARCH METHODS

In March 2013 we searched the following databases: The Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL); Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library); NHS Economic Evaluation Database (The Cochrane Library); Health Technology Assessment (HTA) Database (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) that compared one antibiotic regimen used as prophylaxis for SSIs (and other postoperative infections) with another antibiotic regimen or with no antibiotic, and that reported the methicillin resistance status of the cultured organisms. We did not limit our search for RCTs by language, publication status, publication year, or sample size.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified the trials for inclusion in the review, and extracted data. We calculated the risk ratio (RR) with 95% confidence intervals (CI) for comparing binary outcomes between the groups and planned to calculated the mean difference (MD) with 95% CI for comparing continuous outcomes. We planned to perform meta-analysis using both a fixed-effect model and a random-effects model. We performed intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 12 RCTs, with 4704 participants, in this review. Eleven trials performed a total of 16 head-to-head comparisons of different prophylactic antibiotic regimens. Antibiotic prophylaxis was compared with no antibiotic prophylaxis in one trial. All the trials were at high risk of bias. With the exception of one trial in which all the participants were positive for nasal carriage of MRSA or had had previous MRSA infections, it does not appear that MRSA was tested or eradicated prior to surgery; nor does it appear that there was high prevalence of MRSA carrier status in the people undergoing surgery.There was no sufficient clinical similarity between the trials to perform a meta-analysis. The overall all-cause mortality in four trials that reported mortality was 14/1401 (1.0%) and there were no significant differences in mortality between the intervention and control groups in each of the individual comparisons. There were no antibiotic-related serious adverse events in any of the 561 people randomised to the seven different antibiotic regimens in four trials (three trials that reported mortality and one other trial). None of the trials reported quality of life, total length of hospital stay or the use of healthcare resources. Overall, 221/4032 (5.5%) people developed SSIs due to all organisms, and 46/4704 (1.0%) people developed SSIs due to MRSA.In the 15 comparisons that compared one antibiotic regimen with another, there were no significant differences in the proportion of people who developed SSIs. In the single trial that compared an antibiotic regimen with placebo, the proportion of people who developed SSIs was significantly lower in the group that received antibiotic prophylaxis with co-amoxiclav (or cefotaxime if allergic to penicillin) compared with placebo (all SSI: RR 0.26; 95% CI 0.11 to 0.65; MRSA SSI RR 0.05; 95% CI 0.00 to 0.83). In two trials that reported MRSA infections other than SSI, 19/478 (4.5%) people developed MRSA infections including SSI, chest infection and bacteraemia. There were no significant differences in the proportion of people who developed MRSA infections at any body site in these two comparisons.

AUTHORS' CONCLUSIONS

Prophylaxis with co-amoxiclav decreases the proportion of people developing MRSA infections compared with placebo in people without malignant disease undergoing percutaneous endoscopic gastrostomy insertion, although this may be due to decreasing overall infection thereby preventing wounds from becoming secondarily infected with MRSA. There is currently no other evidence to suggest that using a combination of multiple prophylactic antibiotics or administering prophylactic antibiotics for an increased duration is of benefit to people undergoing surgery in terms of reducing MRSA infections. Well designed RCTs assessing the clinical effectiveness of different antibiotic regimens are necessary on this topic.

Antimicrobial prophylaxis for colorectal surgery

BACKGROUND

Research shows that administration of prophylactic antibiotics before colorectal surgery prevents postoperative surgical wound infection (SWI). The best antibiotic choice, timing of administration and route of administration remain undetermined.

OBJECTIVES

To establish the effectiveness of antimicrobial prophylaxis for the prevention of SWI in patients undergoing colorectal surgery: specifically to determine, 1 Whether it reduces risk of SWI. 2 The target spectrum/a of bacteria (aerobic and/or anaerobic). 3 The best timing and duration of antibiotic administration. 4 The most effective route of antibiotic administration (intravenous, oral or both). 5 Whether any antibiotic is clearly more effective than the currently recommended gold standard.

SEARCH STRATEGY

CENTRAL, MEDLINE, and EMBASE, were searched from January, 1980 to December, 2007.

SELECTION CRITERIA

Randomised controlled trials of prophylactic antibiotic use in elective and emergency colorectal surgery, with SWI as an outcome.

DATA COLLECTION AND ANALYSIS

Data were abstracted and reviewed by three authors for only the single, dichotomous outcome of SWI.

MAIN RESULTS

The review included 182 trials (30,880 participants), and 50 different antibiotics, including 17 cephalosporins. Many studies had multiple variables that separated the two study groups and could not be compared to other studies that tested one antibiotic and had a single variable separating the two groups. Meta-analyses demonstrated a statistically significant difference in postoperative SWI when prophylactic antibiotics were compared to placebo/no treatment (relative risk (RR) 0.30, 95% confidence intervals (CI) 0.22 to 0.41). No statistically significant differences were shown when comparing short- and long-term duration of prophylaxis (RR 1.06, 95% CI 0.89 to 1.27); or single dose versus multiple dose antibiotics (RR 1.17, 95% CI 0.67 to 2.05). Additional aerobic coverage and additional anaerobic coverage both showed statistically significant improvements in SWI rates (RR 0.41, 95% CI 0.23 to 0.71 and RR 0.55, 95% CI 0.35 to 0.85, respectively); as did combined oral and intravenous antibiotic prophylaxis when compared to intravenous alone (RR 0.55, 95% CI 0.41 to 0.74), or oral alone (RR 0.34, 95% CI 0.13 to 0.87). Established gold standard regimens were no less effective than any other antibiotic choice.

AUTHORS' CONCLUSIONS

Antibiotics covering aerobic and aerobic bacteria should be delivered orally and intravenously prior to colorectal surgery. Antibiotics delivered within this framework will reduce the risk of postoperative SWI by at least 75%. Further research is required to establish the optimal timing and duration of dosing, and frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.

Indirect comparison in evaluating relative efficacy illustrated by antimicrobial prophylaxis in colorectal surgery

This paper aims to explore the potential usefulness and limitations of indirect comparisons in evaluating the relative efficacy of interventions. From a systematic review of antimicrobial prophylaxis in colorectal surgery, we identified 11 sets of randomized trials that can be used to compare antibiotics both directly and indirectly. The discrepancy between the direct and the indirect comparison is defined as the absolute value of difference in log odds ratio. The adjusted indirect comparison has the advantages that the prognostic factors of participants in different trials can be partially taken into account and more uncertainty be incorporated into its result by providing a wider confidence interval. However, considerable discrepancies exist between the direct and the adjusted indirect comparisons. When there is no direct comparison, the adjusted indirect method may be used to obtain some evidence about the relative efficacy of competing interventions, although such indirect results should be interpreted with great caution. Further empirical and methodologic research is needed to explore the validity and generalizability of the adjusted indirect comparison for evaluating different interventions.

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

BACKGROUND

A systematic review was carried out to assess the relative efficacy of antimicrobial prophylaxis for the prevention of postoperative wound infection in patients undergoing colorectal surgery.

METHODS

MEDLINE, EMBASE, the Cochrane Trials Register and the references cited in retrieved studies were searched to identify relevant trials published between 1984 and 1995.

RESULTS

Some 147 relevant trials were identified. The quality of trials has improved over the past 12 years. The results confirm that the use of antimicrobial prophylaxis is effective for the prevention of surgical wound infection after colorectal surgery. There was no significant difference in the rate of surgical wound infections between many different regimens. However, certain regimens appear to be inadequate (e.g. metronidazole alone, doxycycline alone, piperacillin alone, oral neomycin plus erythromycin on the day before operation). A single dose administered immediately before the operation (or short-term use) is as effective as long-term postoperative antimicrobial prophylaxis (odds ratio 1.17 (95 per cent confidence interval (c.i.) 0.90-1.53)). There is no convincing evidence to suggest that the new-generation cephalosporins are more effective than first-generation cephalosporins (odds ratio 1.07 (95 per cent c.i. 0.54-2.12)).

CONCLUSION

Antibiotics selected for prophylaxis in colorectal surgery should be active against both aerobic and anaerobic bacteria. Administration should be timed to make sure that the tissue concentration of antibiotics around the wound area is sufficiently high when bacterial contamination occurs. Guidelines should be developed locally in order to achieve a more cost-effective use of antimicrobial prophylaxis in colorectal surgery.

[Antibiotic prophylaxis in hepatobiliary surgery]

Today, hepatic and biliary surgery includes conventional biliary surgery, laparoscopic surgery, interventional radiology, endoscopy and hepatic resection surgery. In conventional biliary surgery, the benefit of antibiotic prophylaxis has been demonstrated. Among the risk factors, some are specific (age > 65 years, gallstones in the common bile duct with or without jaundice, history of acute cholecystitis or of biliary surgery) and the others are non specific such as the CDC new index risk (for scoring from 0 to 3, wound infection rates are respectively 1.36, 2.01, 7.11, 11.54%). The targets for antibiotics used in conventional biliary surgery are E. coli, Klebsiella and Streptococcus. In biliary laparoscopic surgery, the rate of infectious complications and results of antibiotic prophylaxis have not been assessed. However, in laparoscopic surgery, the use of an antibiotic prophylaxis similar to that employed in conventional biliary surgery seems logical. In interventional radiology and endoscopy, the modalities and the benefit of antibiotic prophylaxis have not yet been assessed. Infections (angio-cholecystitis) secondary to these procedures are frequent and severe. They are due to multiresistant hospital microorganisms. Antibiotic prophylaxis regimens for hepatic resections have not yet been assessed and are the same as for conventional biliary surgery.

[Complications in pre- versus intraoperative one-time prophylaxis with cefuroxime after biliary surgery]

The trial was conducted with 66 patients undergoing cholecystectomy. At random, 33 patients received 1.5 g cefuroxime i.v. as a single bolus 20 minutes before surgical incision and 33 patients were injected 20 minutes after incision. The overall incidence of wound infections was 1.51%. In the preoperative group, there was the one wound infection and two patients developed urinary tract infections (incidence of infectious complications 9.1%). In the intraoperative group, one patient developed pneumonia and urinary tract infection and another had urinary tract infection. Wound infections did not occur in this group (incidence of infectious complications 6.1%). Patients with infectious complications had a longer operation time and a longer hospital stay. In conclusion, there was no statistically significant difference in infectious complications when cefuroxime prophylaxis was given preoperatively compared to intraoperative administration.

Single dose cefotaxime plus metronidazole versus three dose cefuroxime plus metronidazole as prophylaxis against wound infection in colorectal surgery: multicentre prospective randomised study

OBJECTIVE

To establish whether a single preoperative dose of cefotaxime plus metronidazole was as effective as a standard three dose regimen of cefuroxime plus metronidazole in preventing wound infection after colorectal surgery.

DESIGN

Prospective randomised allocation to one of two prophylactic antibiotic regimens in a parallel group trial. Group sequential analyses of each 250 patients were performed.

SETTING

14 District general and teaching hospitals.

PATIENTS

1018 Adults having colorectal operations were randomised, of whom 943 were evaluated. Demographic features, conditions requiring surgery, and operative procedures were similar in the two groups. Most patients had surgery for carcinoma of the colon or rectum.

INTERVENTIONS

Group 1 received cefotaxime 1 g intravenously plus metronidazole 500 mg intravenously preoperatively. Group 2 received cefuroxime 1.5 g intravenously plus metronidazole 500 mg intravenously preoperatively, followed by cefuroxime 750 mg intravenously plus metronidazole 500 mg intravenously eight hours and 16 hours postoperatively.

MAIN OUTCOME MEASURES

Development of surgical wound infection (as evidenced by the presence of pus), death, or discharge from hospital.

RESULTS

Wound condition was scored on a five point scale on alternate days until discharge or for up to 20 days postoperatively. Wound infection rates were: group 1, 32/453 (7.1%; 95% confidence interval 4.7% to 9.4%); group 2, 33/454 (7.3%; 95% confidence interval 4.9% to 9.6%). Death rates (group 1: 26/470 (5.5%); group 2: 31/471 (6.6%], the incidence of postoperative complications, the median duration of hospital stay (12 days), and antibiotic tolerance were all similar in the two groups. Pooled data from groups 1 and 2 showed that wound infections were more frequent when minor faecal contamination had occurred at operation and when the duration of operation exceeded 90 minutes (greater than 90 min 11.2% of cases; less than 90 min 4.8%) and were associated with an extended hospital stay.

CONCLUSIONS

A single preoperative dose of cefotaxime plus metronidazole is an efficacious as a three dose regimen of cefuroxime plus metronidazole in preventing wound infection after colorectal surgery and has practical advantages in eliminating the need for postoperative antibiotics.