Choosing antibiotics for intra-abdominal infections: What do we mean by "High Risk"?

Brian R. Swenson, Rosemarie Metzger, Traci L. Hedrick, Shannon T. McElearney, Heather L. Evans, Robert L. Smith, Tae W. Chong, Kimberley A. Popovsky, Timothy L. Pruett, Robert G. Sawyer

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


Background: The definition of "high risk" in intra-abdominal infections remains vague. The purpose of this study was to investigate patient characteristics associated with a high risk of isolation of resistant pathogens from an intra-abdominal source. Methods: All complicated intra-abdominal and abdominal organ/space surgical site infections treated over a ten-year period in a single hospital were analyzed. Infections were categorized by pathogen(s). Organisms designated "resistant" were those that had a reasonable probability of being resistant to the broad-spectrum agents imipenem/cilastatin and piperacillin/tazobactam, and included non-fermenting gram-negative bacilli (e.g., Pseudomonas aeruginosa), resistant gram-positive pathogens, vancomycin-resistant enterococci, and fungi. Patient characteristics were analyzed to define associations with the risk of isolation of "resistant" pathogens. Results: A total of 2,049 intra-abdominal infections were treated during the period of study, of which 1,182 had valid microbiological data. The two genera of pathogens isolated from more than 25% of health care-associated infections and more commonly than from community-acquired infections were Enterococcus spp. (29%) and Candida spp. (33%). Health care association, corticosteroid use, organ transplantation, liver disease, pulmonary disease, and a duodenal source all were associated with resistant pathogens. By multivariable analysis, several acute and chronic measures of disease were predictive of death, with a strong interaction between solid organ transplantation, resistant pathogens, and death. Other links between specific pathogens and patient characteristics were documented, for example, between fungal infection and a gastric, duodenal, or small bowel source, and between liver transplantation and vancomycin-resistant enterococci. Conclusions: On the basis of clinical characteristics, it may be possible to identify patients with intra-abdominal infections caused by pathogens that are potentially resistant to broad-spectrum antibacterial agents. Under these circumstances, and if warranted clinically, broadened coverage probably ought to include specific antienterococcal and anti-candidal therapy.

Original languageEnglish (US)
Pages (from-to)29-39
Number of pages11
JournalSurgical Infections
Issue number1
StatePublished - 2009

ASJC Scopus subject areas

  • Surgery
  • Microbiology (medical)
  • Infectious Diseases


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