Combination versus monotherapy for nosocomial pneumonia

Combination antibiotic therapy of nosocomial pneumonia is sometimes appropriate and desirable; however, it should be used judiciously. When pneumonia appears in the first 5 days following hospital admission and in the absence of other risk factors for infection by multidrug-resistant pathogens, the infection is likely to be due to a pathogen acquired in the community and is likely to be sensitive to most antibiotics. These infections should generally be treated with monotherapy. However, pathogens resistant to multiple drugs are increasingly common in the hospital and intensive care unit setting. In the presence of risk factors for such pathogens, any single drug may prove ineffective; treatment with two or more drugs theoretically increases the likelihood that the pathogen will be sensitive to at least one of them. However, combination therapy also increases the cost and the likelihood of adverse effects, as well as the possibility of drug interactions, if the two are not chosen wisely. The crucial question is whether combination antibiotic therapy actually improves clinical outcome. Most clinical trials suggest that monotherapy and combination therapy provide equivalent efficacy. However, these studies have uniformly excluded the most seriously ill patients: those with Acute Physiology and Chronic Evaluation-II scores .20. It is concluded that available studies provide no concrete evidence to support the use of combination therapy in moderately ill patients and provide no data for the treatment of seriously ill patients who might be most likely to benefit.