Utility of polymerase chain reaction(PCR) according to sampling time in CSF and stool specimens from patient with aseptic meningitis

Abstract

Purpose:Enteroviruses are the most common cause of aseptic meningitis in patients of all ages. A definite diagnosis of enteroviral meningitis can be established by detection of virus directly in CSF specimens. But this is time-consuming and lacks sensitivity, so polymerase chain reaction(PCR) detecting of viral RNA in patient specimens such as CSF, stool has been demonstrated. But little is known about the influence of sampling time on the results of CSF PCR and stool PCR. We investigated diagnostic utility of PCR of CSF and stool according to sampling time after the onset of symptoms. Methods:PCR results were analyzed according to sampling time for 42 patients diagnosed aseptic meningits in our hospital from 11th January to 30th August, 2005. Results:The diagnostic yield of the test was higher of CSF specimens obtained ≦2 days after clinical onset(positive PCR results 9/18, 50 percent), compared with CSF collected >2 days after onset(positive PCR results 1/24, 4.2 percent)(P=0.001). Instead, positive PCR results of fecal specimens maintained highly(average 90.5 percent), 10 cases had also positive PCR results even 5-6 days after onset. 10 cases of CSF specimens had positive enterovirus PCR results containing coxsackievirus B5 (n=6), coxsackievirus B3(n=3). 38 cases of stool specimens had positive enterovirus PCR results containing echovirus 18(n=7), echovirus 9(n=3), coxsackievirus B5(n=8), coxsackievirus B3(n=3). 6 cases(coxackie B5) had positive CSF PCR and stool PCR, both. Conclusion:Stool PCR was clinically sensitive for detecting enterovirus during enteroviral meningits and could give a presumptive diagnosis throughout the disease course. A definite diagnosis was obtained by CSF PCR, but its utility was clearly lower for samples obtained >2 days after clinical onset. Therefore, it is recommended that, in addition to performance of CSF PCR, fecal samples obtained from patients with suspected enteroviral meningitis should be tested by PCR, especially when the duration of symptoms is >2 days