A Danish multicenter study: cefoxitin versus ampicillin + metronidazole in perforated appendicitis

Antibiotic regimens for secondary peritonitis of gastrointestinal origin in adults

BACKGROUND

Secondary peritonitis is associated with a high mortality rate and if not treated successfully leads to development of abscesses, severe sepsis and multi-organ failure. Source control and adjunctive antibiotics are the mainstay of treatment. However, no conclusive evidence suggest that one antibiotic regimen is better than any other but at the same time have a lower toxicity.

OBJECTIVES

To ascertain the efficacy and adverse effects of different antibiotic regimens in treating intra-abdominal infections in adults. Outcomes were divided into primary (clinical success and effectiveness in reducing mortality) and secondary (microbiological success, preventing wound infection, intra-abdominal abscess, clinical sepsis, remote infection, superinfection, adverse reactions, duration of treatment required, effectiveness in reducing hospitalised stay, and time to defervescence).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 4, 2004), MEDLINE (from 1966 to November 2004), EMBASE (from 1980 to November 2004) and Cochrane Colorectal Cancer Group specialised register SR-COLOCA. Bibliographies of identified studies were screened for further relevant trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic regimens in the treatment of secondary peritonitis in adults were selected. Trials reporting gynaecological or traumatic peritonitis were excluded from this review. Ambiguity regarding suitability of trials were discussed among the review team.

DATA COLLECTION AND ANALYSIS

Six reviewers independently assessed trial quality and extracted data. Data collection was standardised using data collection form to ensure uniformity among reviewers. Statistical analyses were performed using the random effects model and the results expressed as odds ratio for dichotomous outcomes, or weight mean difference for continuous data with 95% confidence intervals.

MAIN RESULTS

Fourty studies with 5094 patients met the inclusion criteria. Sixteen different comparative antibiotic regimens were reported. All antibiotics showed equivocal comparability in terms of clinical success. Mortality did not differ between the regimens. Despite the potential high toxicity profile of regimens using aminoglycosides, this was not demonstrated in this review. The reason for this could be the inherent bias within clinical trials in the form of patient selection and stringency in monitoring drug levels.

AUTHORS' CONCLUSIONS

No specific recommendations can be made for the first line treatment of secondary peritonitis in adults with antibiotics, as all regimens showed equivocal efficacy. Other factors such as local guidelines and preferences, ease of administration, costs and availability must therefore be taken into consideration in deciding the antibiotic regimen of choice. Future trials should attempt to stratify patients and perform intention-to-treat analysis to allow better external validity.

Gangrenous and perforated appendicitis: a meta-analytic study of 2532 patients indicates that the incision should be closed primarily

BACKGROUND

Surgical incisions after appendectomy for complicated (gangrenous or perforated) acute appendicitis are often managed with delayed closure (DC) rather than primary closure (PC). This study synthesizes the results of other studies in the surgical literature and supports the routine use of PC.

METHODS

Studies dealing with complicated appendicitis were reviewed to assess the results of PC in comparison with DC. The rate of incision (wound) infection in groups of patients managed by PC and DC were compared with the use of a statistical technique that defined the probability of expected results by incorporating data derived from all of the various study groups.

RESULTS

Of the 2532 patients who had been treated for complicated appendicitis and who were assessed, 1724 patients underwent PC and 808 patients underwent DC. The rate of incision infection was 4.7% and 4.6% in the PC and DC groups, respectively. With a 95% confidence interval, there was no demonstrable difference between the 2 types of operative site management (P < .01).

CONCLUSIONS

PC of the skin and subcutaneous tissue after appendectomy for gangrenous or perforated appendicitis, combined with the use of antibiotic therapy in the perioperative period, is not associated with an increased risk of incision infection when compared with DC.

Adjunctive antimicrobial therapy for complicated appendicitis: bacterial overkill by combination therapy

Although single antimicrobials with broad-spectrum aerobic and anaerobic coverage are effective in patients with appendicitis, many general surgeons continue to use multiple agents. A prospective, double-blind, randomized trial was designed to detect any clinical correlate of in vitro susceptibility advantage of multiple antimicrobials as adjunctive therapy for 114 patients undergoing operation for complicated appendicitis. There was clinical resolution of intraabdominal infections with no occurrence of postoperative infectious complications in 90% (36 of 40) of the cefotetan group and 86% (31 of 36) of the clindamycin/amikacin group (p = 0.11). The number of patients who had changes in antibiotic therapy due to postoperative complications was higher in the clindamycin/amikacin group: five (12.5%), compared to one (2.8%) in the cefotetan group (p = 0.07). Although Bacteroides fragilis group organisms resistant to cefotetan were identified, none was responsible for the postoperative infections. Adverse drug events in 28% of the cefotetan group and 26% of the clindamycin/amikacin group consisted primarily of transient elevations of liver function tests. Monotherapy with a second-generation, broad-spectrum cephalosporin, such as cefotetan, given twice a day is an economical and effective adjunctive regimen in patients with complicated appendicitis for which operation is the definitive treatment. Aminoglycosides and other, more potent antimicrobials should be reserved for resistant organisms or nosocomial infections.

Surgical audit: A prospective study of the morbidity and mortality of acute appendicitis

Between March and September 1989, acute apendicitis was clinically diagnosed in 317 patients who were studied as part of a prospective surgical audit. The study was designed to determine the accuracy of diagnosis, comparison of the macroscopic appearance of the appendix at operation, and subsequent histopathology and complications associated with the morbidity and mortality of emergency appendectomy. The clinical diagnosis was correct in 278 patients (88%). Thirty-nine (12%) of the patients had a negative laparotomy. There was no mortality, and wound infection was the source of increased morbidity in 37 (12%) patients. The highest incidence of wound infection was among those who had pus in the peritoneum (20%) or had a perforated or gangrenous appendix (25%). When the macroscopic appearance of the appendix was compared with the subsequent histopathological findings, a false positive error of 7% and a false negative error of 42% was found. During appendectomy the gross appearance of the appendix must be carefully noted so that a meticulous surgical technique can be complemented by appropriate antibiotic prophylaxis against wound infection, started at the time of surgery.

Combined topical and systemic antibiotic prophylaxis in acute appendicitis

Two hundred forty-six patients with acute appendicitis were randomly assigned to one of two groups. One group of 120 patients received systemic clindamycin preoperatively. Another group of 126 patients received, in addition to systemic clindamycin, a solution of topical ampicillin applied to subcutaneous tissues. No differences were found in the characteristics of the two groups. Combined prophylaxis with clindamycin and ampicillin significantly reduced wound infection to 4%, compared with clindamycin alone (p less than 0.02). A decrease in the surgical wound infection rate in the group treated with clindamycin and ampicillin was mainly observed in patients with advanced (gangrenous and perforated) appendicitis (p less than 0.05). A significant decrease in wound infection rates in patients with positive culture results was also found. We conclude that prophylaxis with a combination of systemic clindamycin and topical ampicillin solution, when compared with clindamycin alone, more effectively prevents wound infection after emergency appendectomy, especially in patients with serious wound contamination.

Antibiotic prophylaxis in acute nonperforated appendicitis. The Danish Multicenter Study Group III

In a prospective, block-randomized, multicenter study, the safety and efficacy of cefoxitin in preoperative prophylaxis were studied. 1735 patients undergoing appendectomy were evaluable, and half of these patients received 2 g of cefoxitin before undergoing operation. The patients were divided into three groups: patients with a normal appendix, patients with an acutely inflamed appendix, and patients with a gangrenous appendix. The study showed for each group a significant reduction of the incidence of wound infection in patients receiving prophylaxis. However, intra-abdominal abscess formation was not influenced by preoperative antibiotic prophylaxis. Consequently, routine preoperative prophylaxis is recommended before appendectomy.

Preventing wound infection after appendicectomy: a review

An exponential increase in the number of published prospective studies reflects both a continuing interest in, and a lack of consensus on, the optimal prophylaxis of wound sepsis after appendicectomy. Review of the literature over the last 25 years leads us to emphasize both the importance of adequate study size and of stratification of the severity of the sepsis found at operation. For critical comparison of prophylactic regimens the high percentage of wound infections disclosed after discharge from hospital must be taken into account. Antibiotics reduce the frequency of wound sepsis and although low wound sepsis rates have been reported with systemic antibiotics active against only anaerobes, the cumulative evidence favours a spectrum of antibacterial activity against both aerobic and anaerobic organisms. Topical antiseptics have no significant effect but topical antibiotics are beneficial. Wide variations in outcome for similar antibiotic regimens reflect the importance of technical factors in determining the frequency of wound sepsis.

Use of new beta-lactam antibiotics for surgical infections

The availability of beta-lactam antibiotics with extended spectra of activity against organisms commonly seen in surgical infections suggests that aminoglycoside-based therapy is no longer needed for most such community-acquired infections. The primary problems with specific beta-lactams are lack of activity against Bacteroides species and variable activity against Pseudomonas aeruginosa and enterococci. The pharmacokinetic properties of the newer beta-lactams vary considerably. This variation suggests specific settings in which these properties may be taken advantage of to improve clinical outcome.

Surgically treated gangrenous or perforated appendicitis. A comparison of aztreonam and clindamycin versus gentamicin and clindamycin

A randomized, double-blinded, controlled clinical study of 84 patients with surgically treated gangrenous or perforated appendicitis was done to compare the efficacy of the combination of aztreonam, the first monobactam antibiotic, with gentamicin when either was combined with clindamycin. Fifty-six patients who were treated with aztreonam and clindamycin (A/C) and 28 patients who were treated with gentamicin and clindamycin (G/C) fulfilled criteria for evaluation. A matched historic control group of 56 G/C patients was also included for comparison. All measures of outcome, including days of fever, hospitalization, antibiotic therapy, and the incidence of antibiotic failures, were similar. It was concluded that aztreonam was as effective as gentamicin in this study and may offer some advantages with regard to toxicity and serum drug level monitoring.

Combined topical povidone-iodine and systemic antibiotics in postappendicectomy wound sepsis

Three hundred and fifteen patients with appendicitis were randomized into two groups. One group received pre-operative systemic gentamicin and metronidazole while the other group received 1 per cent topical povidone-iodine solution in addition to the antibiotics. For early appendicitis including normal and acutely inflamed appendices, only one dose of antibiotics was used. The postoperative wound sepsis was very low in both groups of patients and there was no statistical difference between them. For late appendicitis including gangrenous and perforated appendices, the antibiotics were continued for 7 days. Eight out of 51 patients who had the topical agent developed wound sepsis compared with one out of 52 patients who received no topical agent. This difference is statistically significant (P = 0.03). All wound infections presented within 2 weeks of operation and were deep. Povidone-iodine, 1 per cent, adversely affects the wound infection rate in late appendicitis and should not be used.

Cefotetan compared with gentamicin and tinidazole in acute abdominal surgery

In a prospective randomised trial 190 consecutive admissions undergoing emergency abdominal surgery were allocated to receive a 24-h peri-operative prophylactic regime of either cefotetan or gentamicin and tinidazole. Wound sepsis developed in 14 patients in each group and one patient in each group developed intra-abdominal abscess. Nine patients in the cefotetan group and 10 patients in the gentamicin and tinidazole group died within 1 month of surgery. The death of one patient in each group was directly related to sepsis. Sixty-five per cent of aerobes isolated at operation were sensitive to cefotetan and 62% sensitive to gentamicin. The in vitro anaerobic cover of tinidazole was complete, whereas 13% of anaerobes isolated at operation were resistant to cefotetan. Anaerobes, predominantly Bacteroides fragilis, were isolated from six of the 14 infected wounds following cefotetan prophylaxis and two of the 14 infected wounds in the gentamicin and tinidazole group. It is therefore recommended that cefotetan should be combined with a nitroimidazole in patients undergoing emergency colo-rectal procedures.