Which prophylactic regimen for which surgical procedure?

For optimal prevention of infection subsequent to a surgical intervention, it is necessary to follow a series of general principles, including the classification of the type of surgical intervention, the characteristics of the antibiotic used, and the route and the time of its administration. Moreover, with reference to the different types of surgery, other factors assume importance: the etiology of the infection and the ability of the antibiotic to achieve adequate levels in the tissues at the beginning of the infective process. In general abdominal, biliary, and obstetric-gynecologic surgery, which covers many clean-contaminated and contaminated interventions for which antibiotic prophylaxis has been shown to be the most effective, the etiology is often mixed (aerobic and anaerobic flora) with a predominance of gram-negative microorganisms. Thus, an appropriate prophylactic regimen must consider a third-generation cephalosporin, such as cefotaxime, that is effective against most gram-negative bacteria, in particular against Klebsiella pneumoniae. Acylureido penicillins can also be used because of their activity against enterococci, gram-positive microorganisms that are also causes of infection in this area of surgical intervention. Combining an antimicrobial such as clindamycin or metronidazole, which are particularly active against anaerobes, may be recommended as well. In urologic surgery, most infections are caused by Enterobacteriaceae; in addition to the antimicrobial spectrum, the ability of the antibiotic to concentrate adequately in the urine and renal tissue must also be considered. Beta-lactam antibiotics are the agents of choice, in particular, third-generation cephalosporins, aztreonam, and acylureido penicillins. In cardiac, orthopedic, and partially in neurologic surgery, where most infections are due to gram-positive bacteria (primarily methicillin-resistant staphylococci), antibiotic prophylaxis should include a glycopeptide agent (teicoplanin, vancomycin). In the field of surgical prophylaxis, more experience has been accumulated with cefotaxime, used as a short-course regimen or as a convenient single dose, than with any other newer cephalosporin. Cefotaxime's broad spectrum of action provides coverage against most potential pathogens and, when used as a single dose, is both convenient and cost-effective.