The impact of microbiological diagnostics on the antimicrobial treatment of hospitalised patients with infectious disease.

We evaluated a total of 160 treatment protocols from the unit of internal medicine (n = 100) and the intensive care unit (n = 60) of the Bonn University Hospital to detect the influence of microbiological diagnostics on the individual antimicrobial treatment. Ninety-six of hundred patients in regular care were set on empirical antibiotic treatment within 24 to 48 hours after onset of symptoms. In 91% of the cases cure or substantial improvement was achieved via the initial therapy. Microbiological survey revealed multi-resistant pathogens which could be handled using a specific treatment in six of the remaining patients. In contrast, sixty patients in intensive care proved to benefit significantly from microbiological diagnostics. In one quarter of the cases microbiological findings supported the decision on a reasonable escalated therapy, and in another quarter the initial therapeutic schedule could be confirmed. At any rate, about one third of the infections remained bacteriologically inexplicable in spite of excessive microbiological research. Thus, the results of this retrospective evaluation confirm the common practice of an initial antibiotic treatment without bacteriological investigation in less severe and in severe infections. Microbiological screening may help to decide on effective routine antibiosis in patients with less severe infections. We recommend comprehensive individual microbiological diagnostics in patients with severe nosocomial pneumonia or sepsis and in patients at high risk for Candida superinfections. Due to steadily increasing economic pressure, it is necessary to reflect on the expenditure for microbiological diagnostics. The cost-effectiveness-ratio may be optimised mainly in patients with less severe infections and in regular care. The number of microbiological surveys and expenditures in ICU patients appeared adequate as compared to the individual benefit.