Comparison of classical culture and polymerase chain reaction (PCR) in the detection of vancomycin resistant enterococcus (VRE)

Enterococcus, which have low virulence in natural flora, because of having innate and acquıred resıstance mechanısms agaınst antıbıotıcs, many have been an ımportant place in nosocomial ınfections. For this reason, early detection of VRE colonization, especially in patients with intensive care hospitalizations, is an important threshold to control and prevent the spread of infections. The purpose of our study is to evaluate the comparison of classical culture method (CC) and polymerase chain reaction (PCR) for especially the patients who are at the intensive care unit; by croschecking the classical culture which were executed cocurrently (enterococosel agar) with the conclusion of polymerase chain reaction (PCR) method. During the past 23 months, at the first admission of 311 patients followed in the third stage intensive care unit of our hospital, the perirectal swab specimens taken as two separate swab were evaluated by classical culture and PCR. 66 (%21,2) of 311 were PCR positive, and 32 (%10,2) cases were CC positive. Except 3 samples, 29 samples which CC positive were also PCR positive. PCR positivity was detected In 66 cases, VanA gene was detected in 58, VanB gene in 6, and VanA+VanB gene in 2 samples. Twenty-seven samples with positive VanA gene and 2 with VanA+VanB gene were found positive in the culture, whereas the sample with 3 VRE culture positive gave PCR negative results. When the results of the study are evaluated, PCR will be faster than the culture, so the isolation precautions to be taken immediately will prevent both the infection of the other patients and the carrier which can result in transmission to healthcare workers. Thus achieving the result that VRE can be avoided from hospital and hospital outbreaks. However high false positive rate of PCR method ensues that the positive predictive value is low. Because of the low sensitivity and specificity of the PCR method, concurrent use of two methods in intensive care should be considered to produce more healthy results.