Wrong bacteria often targeted in pancreaticoduodenectomy

Last Updated: 2015-12-28

By David Douglas

NEW YORK (Reuters Health) - Standard antibiotic prophylaxis for pancreaticoduodenectomy (PD) may miss important pathogens, according to U.S. and Italian researchers.

As Dr. Carlos Fernandez-del Castillo told Reuters Health by email, "Bile is normally sterile but becomes colonized when the biliary tract is instrumented. This study provides further evidence that bacteria present in the bile is often the same that grows from a wound abscess occurring after pancreaticoduodenectomy, and very often is not covered with the antibiotics that are commonly used for wound infection prophylaxis."

In a December 23 online paper in JAMA Surgery. Dr. Fernandez-del Castillo, of Massachusetts General Hospital, Boston, and colleagues report that they came to these conclusions after studying data on more than 1,600 patients.

The patients underwent the procedure between 2008 and 2013 at one of three institutions. In all, 133 patients (8.2%) with wound infections were identified. Infection rate did not differ significantly by institution.

Of the wound infections, 89 (67.1%) were deep-tissue, occurring at a median of eight days after the procedure. In all, 53 (40.0%) of the infections required home visiting nurse services after discharge. Moreover, 73 (29.1%) of all readmissions were attributed to wound infection.

The strongest predictor of postoperative wound infection was preoperative biliary stenting (odds ratio, 2.5, p=0.03).

There was marked institutional variation in the type of microorganisms cultured from both the intraoperative bile and wound infection. Favored antibiotics also differed. The first institution predominantly used cefoxitin sodium, the second cefazolin sodium with metronidazole, and the third, ampicillin sodium-sulbactam sodium.

Streptococcus pneumoniae, was seen in 47.9% of the intraoperative bile cultures from institution A but only 4.5% from cultures from the others. Corresponding predominant microorganisms in wound infection cultures were Enterococcus faecalis 51.4%, Staphylococcus aureus, 43.9%, and Escherichia coli, 36.2%, respectively (p=0.001).

Predominant antibiotic resistance patterns similarly varied by institution -- cefoxitin (53.1%), ampicillin-sulbactam (69.2%) and penicillin (72.7%), respectively.

The researchers conclude, "None of the three institutions analyzed was using effective antibiotic prophylaxis." They propose that "intraoperative bile cultures should be routinely obtained during PD to predict microorganisms isolated in wound cultures and allow for tailored antibiotic therapy in the setting of pending or unavailable wound culture data, especially if there has been preoperative biliary manipulation."

Commenting on the findings by email, Dr. Luke O. Schoeniger, coauthor of an accompanying editorial, told Reuters Health that the researchers "present strong evidence for the causal link between preoperative biliary manipulation and postoperative infections."

Dr. Schoeniger, of the University of Rochester Medical Center, New York, added, "We point out that collecting intraoperative bile cultures predicts the bacteriology of subsequent infections but does not prevent them. Better operative and antibiotic utilization strategies will need to be defined by future studies."

The authors reported no funding or disclosures.

SOURCE: http://bit.ly/1Jcd7aW and http://bit.ly/1R3w0OF

JAMA Surg 2015.