PCR检测与细菌培养方法在细菌性痢疾监测中的应用比较

Underestimated incidence rate of shigellosis: comparison of PCR and coproculture methods in a surveillance study

目的通过与PCR检测比较,确定细菌培养方法对细菌性痢疾疾病负担的低估程度。方法从2002年细菌性痢疾监测研究获得的10105份腹泻标本中随机选取337份,采用针对ipa H基因的PCR方法检测其志贺菌感染,并同传统细菌培养方法进行比较。结果337份腹泻标本中检测到ipa H基因212份,检出率为62.9%;而粪便培养阳性为39份,检出率为11.6%(P<0.001)。Logistic回归分析显示影响PCR检出的因素依次为细菌培养结果(OR=15.5;95%CI:2.0-119.0),具有发热症状(OR=2.8;95%CI:1.2-6.2),菌痢流行季节的腹泻(OR=2.4;95%CI:1.4-4.3)及女性病例(OR=1.8;95%CI:1.1-3.0)。结论与PCR检测相比,传统细菌培养方法使得菌痢的发病率在相当大的程度上被低估。

Purpose To define the magnitude of potential underestimate of disease burden due to shigellosis. Methods PCR was applied to detect Shigella infection compared to coproculture. Rectal swab specimens of 39 Shigella culture positive and 298 Shigella culture negative patients from a population-based surveillance were selected randomly. Both conventional culture and real-time PCR with primer pair targeted to the invasion plasmid antigen H gene sequence （ipaH） were employed to conduct those randomized specimens. Results Shigella. spp was isolated from 39 （11.6%） of 337 stool specimens by conventional coproculture. Conversely, ipaH were detected in 212 （62.9%） of 337 randomly stool specimens （P〈0. 001）. A logistic regression analysis found culture results was the strongest predictive factor for PCR positive （OR = 15.5; 95 0% CI： 2.0 - 119.0）, followed by diarrhea with fever （OR= 2.8; 95% CI： 1.2- 6.2）, epidemic season （OR= 2.4; 95% CI： 1.4- 4.3）, female gender （OR = 1.8; 95% CI： 1.1 - 3.0）. Conclusions The high detection rate of ipaH through realtime PCR indicated the incidence rate of shigellosis diagnosed by conventional culture might cause a considerable underestimation.