[Duration of the preventive use of antibiotics in colorectal surgery--single administration versus short-term prevention]. Prospective, randomised study on antibiotic prophylaxis in colorectal surgery. Is it really necessary to use oral antibiotics? Selective decontamination of the colon before elective colorectal surgery. West of Scotland Surgical Infection Study Group. [Parenteral antibiotic prophylaxis or oral antimicrobial bowel preparation for colorectal surgery (author's transl)]. Value of oral antibiotic prophylaxis in colorectal surgery. Prophylactic antibiotics in elective colorectal surgery. Should antimicrobial prophylaxis in colorectal surgery include agents effective against both anaerobic and aerobic microorganisms? A double-blind, multicenter study. The Norwegian Study Group for Colorectal Surgery. Short-term antibiotic prophylaxis in elective colorectal surgery. Prophylaxis of infection following colorectal surgery.
The effect of a combination of 4 g mezlocillin and 0.5 g metronidazole for the prophylaxis against infections in a one-shot dose immediately preoperatively compared to a short-time dose of 2 days given to 90 patients with resection of colorectal carcinoma was investigated in a prospective and randomized study. 6 patients developed a wound infection in the early postoperative phase; 4 of these infections (3 were severe, 1 was mild) occurred in the one-shot group and 2 in the short-time prophylaxis group. After more than 20 days postoperatively 3 late infections were observed which had a mild course (2 cases in the one-shot group, 1 case in the short-time prophylaxis group). All infections were localized in the sacral wound region in patients with abdominoperineal resection. The abdominal wounds healed per primam in each case. Besides those, 26 infections of the urinary tract were observed, which occurred significantly more often after the one-shot dose (40.9%) than with the short-time prophylaxis (18.6%). Intraoperative smears of the lumen of the bowels showed a remaining bacterial settlement. Besides Bacteroides species, especially Escherichia coli were found among the isolates. Moreover in some cases Clostridium, Klebsiella, Proteus and Pseudomonas could be identified. Smears of the site of operation (sacral/peritoneal cavity) were contaminated in over 50%, above all by Bacteroides species; besides those, E. coli were found most often. The subcutaneous smears showed a growth of the germs only in a few cases. Aerobic bacteria in 93.8%, anaerobic bacteria except for thetaiotaomicron and B. asaccharolyticus in 85.1%.(ABSTRACT TRUNCATED AT 250 WORDS) The use of prophylactic antibiotics in addition to mechanical cleansing is the current standard of care prior to colonic surgery. The question of whether the antibiotics should be administered intravenously or orally, or by both routes, remains controversial. Our aim was to compare three methods of prophylactic antibiotic administration in elective colorectal surgery.
                Three hundred consecutive elective colorectal resections were studied. All patients had preoperative mechanical colon cleansing with oral sodium phosphate and intravenous antibiotic prophylaxis with cefoxitin (one dose before skin incision and two postoperative doses). Patients were randomised to one of the following three groups: group A: three doses of oral antibiotic (neomycin and metronidazole) at the time of mechanical colon cleansing; group B: one dose of oral antibiotic; group C: no oral antibiotics. All patients were followed during their hospital stay and at 7, 14 and 30 days post-surgery.
                Vomiting occurred in 31%, 11% and 9% of the studied patients (groups A, B and C, respectively) (p<0.001). Nausea was present in 44%, 18% and 13% of patients (p<0.001). Abdominal pain was recorded in 13%, 10% and 4% of patients (p: 0.077). Wound infection was present in 7%, 8% and 6% and suture dehiscence occurred in 2%, 2% and 3% of the patients in the three groups (no differences among them). Neither were differences found among the three groups in terms of urinary infections, pneumonia, postoperative ileus or intra-abdominal abscess.
                The addition of three doses of oral antibiotics to intravenous antibiotic prophylaxis is associated with lower patient tolerance in terms of increased nausea, vomiting and abdominal pain, and has shown no advantages in the prevention of postoperative septic complications. Therefore, we recommend that oral antibiotics should not be used prior to colorectal surgery. The controversy over the route of administration of antibiotic prophylaxis in patients undergoing elective colorectal operations persists for oral, parenteral, and a combination of the two routes. The oral antibiotics commonly administered for colorectal prophylaxis, neomycin and eythromycin base, are not absorbed in the gastrointestinal tract (GIT). However, the 4-fluoroquinolones are absorbed in the upper GIT and are excreted in part by the colonic mucosa. Their action is then to remove, or severely depress, the gram-negative aerobic bacilli leaving the anaerobic flora unaffected. This action is the principle of selective decontamination. We have assessed the efficacy of oral ciprofloxacin in a prospective randomized clinical trial in which all patients received piperacillin 4 g i.v. as single-dose parenteral prophylaxis. A group of 327 evaluable patients were randomized to receive ciprofloxacin 500 mg b.i.d. with the preoperative cathartic (group OA, n = 159) or no oral antibiotic (group NOA, n = 168). Postoperative wound infection occurred in 18 (11.3%) patients in group OA and 39 (23.2%) patients in group NOA (chi 2 = 7.2, p = 0.007). Operation-related infection of any type occurred in 23 (14.5%) patients in group OA compared with 55 (32.7%) in group NOA (chi 2 = 14.0, p = 0.0002). The median postoperative hospital stay was 11 days (interquartile range 4.5 days) for group OA and 12 days (interquartile range 8 days) for group NOA (Mann Whitney U test, p = 0.005). Ignoring the treatment group, the median postoperative hospital stay was 17 days (interquartile range 10 days) for infected patients and 11 days (interquartile range 4 days) for those not infected.(ABSTRACT TRUNCATED AT 250 WORDS) A prospective randomized trial was designed to establish whether parenteral antibiotic prophylaxis was as effective as oral antimicrobial bowel preparation in preventing sepsis after colorectal surgery. Patients scheduled for elective resection of colorectal cancer received metronidazole and kanamycin either orally in the preoperative phase or parenterally as a short-term perioperative prophylaxis. The former regimen resulted in reduction of the microbial concentrations in the bowel contents in the absence of therapeutic serum concentrations at the time of operation, whereas the latter achieved therapeutic intraoperative serum levels without altering the colonic microflora. 72 patients were studied. There was no significant difference in the occurrence of postoperative sepsis between the two groups (a total of 72 patients). These results differ from those obtained at the Birmingham General Hospital using the same protocol, in which postoperative sepsis was significantly more common in the group of patients having oral bowel preparation. This difference was most probably due to an overgrowth of kanamycin-resistant coliforms during the period of oral antibiotic preparation. The presence of resistant organisms did not, however, result in failure of systemic prophylaxis. The authors conclude that short-term parenteral application is the safer method of antibiotic prophylaxis in colorectal surgery and is to be preferred to oral antimicrobial bowel preparation. A total of 169 patients undergoing colorectal surgery were randomly allocated to receive either gentamicin plus metronidazole or oral ciprofloxacin plus metronidazole as prophylaxis; they were also allocated to receive cover for 1 or 3 days. Twenty-eight patients (17 per cent) developed postoperative wound infections. The proportion of patients with wound infections and other infective complications was significantly less (P < 0.02) in those receiving oral ciprofloxacin. Cover for 3 days was no better than that for only 1 day. Oral ciprofloxacin for prophylaxis may offer advantages in efficacy and ease of administration compared with parenteral antibiotics. A randomized prospective study was conducted on 194 patients who underwent elective colorectal surgery for carcinoma. All patients received the same mechanical bowel preparation. In addition, patients in group A received oral neomycin and erythromycin base; patients in group B received systemic metronidazole and gentamicin, while patients in group C received both oral and systemic antibiotics. Postoperative septic complications related to colorectal surgery occurred in 27.4 per cent, 11.9 per cent and 12.3 per cent respectively in groups A, B and C (chi 2 = 7; P less than 0.05). The incidence of sepsis in groups B and C was almost identical. Patients who received oral antibiotics alone (group A) had significantly higher risks of postoperative sepsis when compared with patients in either group B or group C (P less than 0.05). As there is no additional advantage of combining oral and systemic antibiotics, we recommend systemic metronidazole and gentamicin to be used with mechanical bowel preparation in elective colorectal surgery. It is now well demonstrated that a mixed flora of aerobic and anaerobic microorganisms will be found in wound abscesses and peritonitis after bowel surgery. An impressive reduction in infectious complications caused by anaerobic microorganisms can be achieved with nitroimidazole prophylaxis, but considerable uncertainty about the role of agents active against aerobic microorganisms in such prophylaxis still exists. We have earlier reported that a single dose of tinidazole and doxycycline significantly reduces postoperative infections and is superior to doxycycline alone. The effect of an agent active only against anaerobic microorganisms was tested in a double-blind study of 267 patients who underwent elective colorectal surgery. The patients received either tinidazole (1600 mg) and placebo or tinidazole (1600 mg) and doxycycline (400 mg) as a single preoperative infusion. Patients who received tinidazole and doxycycline had significantly fewer infectious complications, reoperations, additional use of antibiotics, and a shorter hospital stay. Microbiologic studies demonstrated that tinidazole alone gave effective protection against anaerobic organisms but did not protect the patients from aerobic gram-negative infectious complications. A single preoperative dose of antimicrobial agents effective against both anaerobic and aerobic bowel organisms seems to be the preferred prophylaxis for patients undergoing colorectal surgery. In the last 2 years, 50 patients who underwent elective colorectal surgery were prospectively studied about antibiotic prophylaxis. Two groups of 25 patients each were randomly selected. Both received: (a) a colic preparation: hypactic drugs and two enemas during the day before surgery and (b) metronidazole 0.5 g plus neomycin 1 g per 8 h orally for 1 day before surgery. Every group also received: group A, metronidazole 0.5 g plus amikacin 500 mg i.v. 2 h before surgery and the same doses per 8 or 12 h, respectively, for 2 days postoperatively; group B, ornidazole 1 g by intravenous infusion plus ceftriaxone 2 g i.v. 2 h before surgery and the same doses of the drugs per 24 h for 2 days postoperatively. Wound infection occurred in 1 case of group A versus 2 cases of group B (p greater than 0.25). Ornidazole plus ceftriaxone prophylactic antibiotic therapy is therefore as effective as a classic therapy (metronidazole plus amikacin) and constitutes an alternative choice for patients undergoing elective colorectal surgery, because the simple manner of its administration (once per 24 h) is resulting in cost saving due to gained nursing time. Due to the high incidence of infective complications following colorectal surgery, prophylactic application of systemic antibiotics is required. In a prospective, randomised study of 34 patients who underwent elective colorectal surgery, it was found that a single 1 g dose of cefotaxime was as effective as three doses in controlling post-operative infections. Both groups received 500 mg metronidazole i.v. every 12 h for 72 h, with the first dose administered immediately prior to surgery. The results indicate that prophylactic cefotaxime and metronidazole are effective in reducing the incidence of septic complications following colorectal surgery; nevertheless, a study with a larger number of patients is needed to reach a definitive conclusion.
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.