[Molecular biological sepsis diagnostic using multiplex PCR in surgical intensive care as suitable alternative to...

Sepsis causes a substantial rate of morbidity and mortality in intensive care patients, which is, in particular, triggered by an inadequate antimicrobial treatment from the beginning. Conventional microbiological standard procedures cannot provide valuable information on bacterial or fungal species of sepsis-relevant microbes within the first hours of a developing sepsis. However, multiplex PCR (PCR-M) focussing on the spectrum of the most relevant sepsis-associated microbes can considerably shorten the time period; the analytical tests have been standardised and, subsequently, inaugurated into clinical practice; they also have thus been available since 2005. Interestingly, in the surgical field an appropriate summary and concluding recommendation have been lacking so far. AIM, MATERIAL AND METHODS: A compact short overview based on a characteristic selection of relevant references from the literature is given on the commercially available sepsis-associated multiplex-PCR methods, reflecting critically the time point of inauguration, clinical value and future perspectives including our own experiences from clinical practice and medical studies.

Multiplex PCR in adult sepsis patients yielded in a range from 13.7 to 39.9 % of positive findings, whereas conventional blood cultures only range from 8 to 29.9 %. From 8 to 16.9 % of all investigations performed prompted us to a change of the antimicrobial treatment by using a positive PCR-M finding. A prospective study (end-point, reduction of sepsis-associated mortality) has not yet been initiated. Positive PCR-M findings correlate with an increased morbidity and mortality as well as clinical and laboratory sepsis parameters. Recent studies have aimed for a comparison of PCR-M on sepsis-associated microbes with regard to specificity and sensitivity with the current "gold standard", conventional blood culture. A few studies wrongly claimed to compare the methods because of the difference in the procedures; in addition, blood culture as gold standard has been increasingly considered as very problematic from a methodological point of view. Recent publications on multiplex-PCR studies in frequently heterogenic groups of patients have been mostly performed with the Lightcycler-Septifast® test (LC-SF) with great success. The procedure has provided evidence of an improved detection rate of sepsis-associated microbes, favourable concordance of positive PCR-M findings with clinical and laboratory sepsis parameters and substantial time-saving in the microbiological analysis of the specific microbial species, which is simultaneously associated with an earlier initiation of an adequate antimicrobial treatment regimen.

The available study data suggest that systrematic investigations on the molecular biological procedures should be rather related to a different standard based on the LC-SF. Positive PCR-M findings have been accepted as a sepsis marker in the mean time.