The value of oral antibiotic prophylaxis in biliary tract surgery

Cholangitis in the postoperative course after biliodigestive anastomosis

BACKGROUND

Hepatobiliary surgery with biliodigestive anastomosis (BDA) results in a loss of the sphincter of Oddi with consecutive ascension of bacteria into the bile system which may cause cholangitis in the postoperative course.

METHODS

Patients who received reconstruction with a BDA after hepatobiliary surgery were analyzed retrospectively for their postoperative course of disease depending on intraoperatively obtained bile cultures and antibiotic prophylaxis.

RESULTS

Two hundred forty-three patients were included in the analysis, 49.4 % of whom had received endoscopic stenting before the operation. Stenting was significantly associated with the presence of drug-resistant bacteria in the intraoperatively obtained bile sample (p < 0.001, OR = 4.09). Of all patients, 14.4 % developed postoperative cholangitis. This was significantly associated with the postoperative length of stay in the intensive care unit (p = 0.002, OR = 1.035). The highest incidence of postoperative cholangitis was found in patients with cholangiocellular carcinoma (n = 12, p = 0.046, OR = 2.178). Patients were more likely to harbor strains with resistance against the antibiotic that was given intraoperatively.

CONCLUSION

The risk for the presence of drug-resistant bacteria is increased by preoperative stenting of the common bile duct. Bile culture by intraoperative swabs can be altered by the perioperative antibiotic prophylaxis as it induces microbiological selection in the common bile duct.

The role of quinolones in abdominal surgery

The quinolone antibiotics have been a major advance for the treatment of various types of infections. These agents have generally good safety profiles, broad-spectrum activity, and favorable pharmacokinetics. In addition, several of these antibiotics are available in both intravenous and oral formulations, which allows for sequential therapy resulting in potential cost savings. However, patients can develop serious central nervous system side effects (seizures) and phototoxicity. In addition, the bioavailability of agents in this class can be reduced by coadministration with cations, such as magnesium, aluminum, calcium, and iron, which may make bioavailability unpredictable in patients. Although older quinolones such as ciprofloxacin were effective as prophylactic agents for biliary procedures and colorectal surgery and for the treatment of intra-abdominal infections, the use of these older quinolones was limited by the development of resistant organisms. In addition, because these agents had poor activity against anaerobes such as Bacteroides fragilis, the agents had to be combined with an antianaerobic agent, such as metronidazole, when anaerobic coverage was required. Recently, a new quinolone, trovafloxacin, has become available. Trovafloxacin has demonstrated increased activity against anaerobes in animal and human studies. However, the clinical profile of trovafloxacin for abdominal infections has not been fully demonstrated, and there is some concern that its activity against aerobic gram-negative bacilli, especially Pseudomonas aeruginosa, may not equal that of ciprofloxacin. Moreover, the safety profile of trovafloxacin is disadvantageous owing to reports of severe hepatic toxicity.

Review article: antibiotic prophylaxis for endoscopic retrograde cholangiopancreatography (ERCP)

This review examines the evidence for antibiotic prophylaxis in endoscopic retrograde cholangiopan-creatography (ERCP), and provides detailed advice about suitable antibiotic regimens in appropriate high-risk patients. Ascending cholangitis and infective endocarditis are potential complications of endoscopic ERCP. The pathophysiology of these two complications is quite separate and different sub-groups of patients require prophylaxis with appropriate antibiotic regimens. Ascending cholangitis results from bacterial infection of an obstructed biliary system, usually from enteric Gram-negative microorganisms, resulting in bacteraemia. There is incomplete drainage of the biliary system after ERCP in up to 10% of patients who require stenting. Antibiotics started in these patients will probably reduce the frequency of cholangitis by 80%. If antibiotics are restricted to this group, approximately 90% of all patients having an ERCP will avoid antibiotics, but 80% of cholangitic episodes will be prevented. Infective endocarditis may result from the bacteraemia caused at the time of the ERCP in patients with an abnormal heart valve. Antibiotic prophylaxis, in particular covering alpha-haemolytic streptococci, should be started before the procedure in this defined high-risk group.

Biliary tract infections: a guide to drug treatment

Initial therapy of acute cholecystitis and cholangitis is directed towards general support of the patient, including fluid and electrolyte replacement, correction of metabolic imbalances and antibacterial therapy. Factors affecting the efficacy of antibacterial therapy include the activity of the agent against the common biliary tract pathogens and pharmacokinetic properties such as tissue distribution and the ratio of concentration in both bile and serum to the minimum inhibitory concentration for the expected micro-organism. Antimicrobial therapy is usually empirical. Initial therapy should cover the Enterobacteriaceae, in particular Escherichia coli. Activity against enterococci is not required since their pathogenicity in biliary tract infections remains unclear. Coverage of anaerobes, in particular Bacteroides spp., is warranted in patients with previous bile duct-bowel anastomosis, in the elderly and in patients in serious clinical condition. In patients with acute cholecystitis or cholangitis of moderate clinical severity, monotherapy with a ureidopenicillin--mezlocillin or piperacillin--is at least as effective as the combination of ampicillin plus aminoglycoside. In severely ill patients with septicaemia, an antibacterial combination is preferable. Therapy with aminoglycosides, mostly for Pseudomonas aeruginosa-related infections, should not exceed a few days because the risk of nephrotoxicity seems to be increased during cholestasis. Relief of biliary obstruction is mandatory, even if there is clinical improvement with conservative therapy, because cholangitis is most likely to recur with continued obstruction. Emergency invasive therapy is reserved for patients who fail to show a clinical response to antibacterial therapy within the first 36 to 48 hours or for those who deteriorate after an initial clinical improvement. Immediate surgery is indicated for gangrenous cholecystitis and perforation with peritonitis. Long-term administration of antibacterials is required for recurrent cholangitis, as seen in bile duct-bowel anastomosis. Oral cotrimoxazole (trimethoprim/sulfamethoxazole) is the preferred agent. Wound infection rates after biliary tract surgery can be significantly reduced by preoperative administration of prophylactic antibacterials. Newer generation beta-lactams have not proven to be of greater benefit than older agents such as cefuroxime or cefazolin. Antibacterial prophylaxis before endoscopic retrograde cholangiopancreatography (ERCP) should be reserved for patients with obstructive jaundice, since the risk of infectious complications seems to be strongly associated with this clinical condition. Failure to achieve full biliary drainage is the most important factor in predicting septicaemia, and prophylaxis should be prolonged until the bile duct is unobstructed. Piperacillin, cefazolin, cefuroxime, cefotaxime and ciprofloxacin are effective for this indication.

[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.

[The role of new molecules in surgical antibiotic prophylaxis]

The preoperative administration of a new antibiotic for antimicrobial prophylaxis is questionable because of the methodological difficulties to demonstrate its efficiency and benefits in decreasing the postoperative infectious complications. As their rate is very low, especially in clean surgery, the number of patients to be included in a comparative trial is very high. Most studies assessed only small groups and therefore any extrapolation for clinical practice is of limited value. Because of their therapeutic efficiency the fluoroquinolones are often recommended for antimicrobial prophylaxis. However, the rapid occurrence of resistances, directly related to their prescription should invite the prescribers to be cautions. They should be contra-indicated as long as an alternative of similar efficiency is existing, in case of bacteraemia, when an administration of more than 48 hours in required or when the intra-hospital resistance rate exceeds 10 p. 100.