A new PCR method for detection of bacteria and fungi in biological sample.
In the treatment of bloodstream infections the most important and difficult problem of determining the effectiveness of treatment and, consequently, the cost and time of hospitalization is the effective diagnosis of factors causing a systemic inflammatory response in sepsis. The material subjected to diagnostic testing is blood taken from a patient showing clinical signs of sepsis. The greatest difficulty is the very small amount of microorganisms being responsible for the infection in the blood, or they are only periodically seeded into the blood. Currently, the standard diagnostic blood cultures are performed with specialized broth media, preferably in automatic culture systems. A weakness of these methods are time consumption (until a result of the study) and low sensitivity, which causes that in only 15-20% of the culture it is possible to achieve the growth of microorganisms. The situation is further complicated by the fact that patients undergo antibiotic treatment before a blood sample is taken for culture. In this case blood cultures are very difficult due to the fact that they contain antibiotics which inhibit the growth of microorganisms. The molecular biology techniques, such as PCR or hybridization, belong to diagnostic methods that provide reliable, accurate and fast diagnosis of bloodstream infections. The sensitivity of molecular methods is much higher than the sensitivity of the culture method. However, currently available systems enable the detection of several particular species of microorganisms or every possible gene in theory, but on the other hand they require sequencing of PCR product, which in turn increases the cost and time for the result. The proposed new PCR method allows simultaneous DNA detection of the entire panel of bacterial and fungal microorganisms, with the differentiation of Gram-negative bacteria, Gram-positive bacteria, yeasts fungi and molds in a sample of biological material (including patient's spittle or blood). There is the possibility of using the detection method only for bacteria or fungi, or for the simultaneous detection of both fungi and bacteria, which reduces the cost of testing. There is also the opportunity to identify a specific species of microorganism after sequencing of the PCR product.