[Microbial spectrum in surgical infections based on a microbiological routine monitoring over the 10-year period from 1995 to 2004]

Abstract

Introduction: Infections belong to the most frequent and dangerous complications in surgery. In addition to the medical aspects, these infections may have a significant impact on the costs and the overall economic efficacy of medical treatment under the present circumstances of DRG.

Aim: A systematic, prospective collection and retrospective evaluation of all consecutive microbiological analyses in specimens from the 3 medical floors (except the ICU) of the Department of Surgery at the University Hospital, Magdeburg (Germany) was performed in 1995, 2002 and 2004 to characterise i) the 10-year course (1995 vs. 2004) and ii) possible alterations due to changes in the previously existing pavillon system (2002 vs. 2004).

Patients and methods: The microbial spectrum was determined in the 3 most frequent specimen types (blood culture, urine sample, wound swab) including number and percentage of the single microbial groups such as gram-positive and gram-negative Enterobacteriae, pseudomonades and fungi. In addition, the antibiotic resistance of selected microbes was analysed. The primary data were registered in a database and evaluated according to the various questions.

Results: Overall, 2 979 microbes were identified in 1995 (2002, 1 338; 2004, 915). On comparing 1995 with 2004, the percentage of gram-positive microbes did not change (50.5 vs. 50.3 %), whereas the percentage of gram-negative enterobacteriae increased: 37.4 vs. 29.1 %. The percentage of detected fungi was only half of that in 1995: 6.2 vs. 12.2 %. In blood cultures, the Klebsiella spp. portion in the group of gram-negative enterobacteriae distinctly increased: 29.6 vs. 18.8 %. While in 2004, MRSA was found in 24.4 % of all detected Staphylococcus aureus strains in swab specimens amounting to a considerable increase compared to 2002 (17.6 %), in 1995, MRSA was not isolated at all in this material. In the fungi group, there was a decrease of the Candida albicans portion vs. the non-C. albicans strains, which was associated with an increasing resistance against fluconazol. This requires treatment with caspofungin, resulting in increased costs vs. those necessary for fluconazol treatment.

Conclusion: A systematic, microbiological, long-term monitoring is indispensable since i) microbial detection plays a growing role to include the various types of infections in the spectrum of diagnosis for DRG, ii) alterations of the microbial spectrum can only be detected through a long-term observation period (MRSA, fungi) and iii) simultaneously developing antibiotic resistances can be determined (MRSA, ESBL strains in Enterobacteriae, fluconazol-resistant fungi). This can have an infectious, biological, hygienic and cost-determining as well as a health policy relevance among others, with considerable additional costs (e. g., isolation of patients, cost-intensive substitutional medication) with necessary reimbursement.