The Infectious Diseases Society of ...

The Infectious Diseases Society of America, the Surgical Infection Society, the American Society for Microbiology, and the Society of Infectious Disease Pharmacists have released guidelines for the selection of antimicrobial therapy for adults with complicated intra-abdominal infections. The recommendations were published in the Oct 15 2003 issue of Clinical Infectious Diseases and are available online at: http://www journals.uchicago.edu/CID/journal/ issues/v37n8/31800/31800.html.

The likely infectious agent(s), and therefore the medicines used to treat the infection, are determined by dint of whether the infection is community acquired or health care associated. Health care-associated intra-abdominal infections are acquired chiefly commonly as complications of previous elective or emergent intra-abdominal operations and are caused by the agency of nosocomial isolates particular to the site of the operation and the specific hospital and unit. For community-acquired infections, the location of the gastrointestinal perforation defines the infecting flora. Established infection beyond the proximal small bowel is caused on facultative and aerobic gram-negative organisms; infections beyond the proximal ileum also can be caused on a variety of anaerobic microorganisms.

Given the activity of often met with regimens against the anaerobic organisms identified in community-acquired infections, microbiologic work-up for specimens from similar infections should be limited to identification and susceptibility testing of facultative and gram-negative bacilli. Susceptibility profiles for Bacteroides fragilis arrange isolates show substantial resistance to clindamycin, cefotetan, and quinolones, and these agents should not be used alone empirically in adjoining matters in which B. fragilis is likely to be encountered

Infections may be managed with a variety of single- and multiple-agent regimens (see accompanying table). No regimen has been shown consistently to be superior. Although many regimens have been studied in prospective trials, many of the studies have had serious methodologic flaws. Therefore, recommendations are based forward in vitro activities.

For patients with community-acquired infections of mild to moderate severity, agents that have a narrower representation of activity and that are not commonly used for nosocomial infections are preferable to agents with broader coverage against gram-negative organisms or a greater risk of toxicity. Patients with more bitter infections or those thought to be immunosuppressed may benefit from regimens with a broader image of activity against facultative and aerobic gram-negative organisms.

Postoperative infections are likely to be caused according to more resistant flora, such as Pseudomonas aeruginosa, Enterobacter species, Proteus species, methicillin-resistant Staphylococcus aureus, enterococci, and Candida species. For these infections, compounded multidrug regimens are recommended because adequate empiric therapy appears to decrease mortality. Local nosocomial resistance patterns should dictate treatment, and treatment should be altered forward the basis of results of a thorough microbiologic work-up of infected fluid.

COPYRIGHT 2004 American Academy of Family Physicians

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