Kalach Nicolas, Gosset Pierre, Dehecq Eric, Decoster Anne, Spyckerelle Claire, Papadopolos Stephan, Dupont Christophe, Raymond Josette
*Clinique Pédiatrique St Antoine †Département d'Anatomopathologie, Hôpital St Vincent de Paul ‡Département de Microbiologie, Hôpital St Philibert, Groupement des Hôpitaux de l'Institut Catholique de Lille, Lille §Service de Gastroentérologie Pédiatrique, Hôpital Necker-Enfants-malades, AP-HP ||Service de Microbiologie, Hôpital Cochin, Université Paris V-René Descartes, Paris, France.
J Pediatr Gastroenterol Nutr. 2015 Sep;61(3):307-12. doi: 10.1097/MPG.0000000000000787.
The aim of the study was to assess the usefulness of gastric biopsy-based quantitative real-time polymerase chain reaction (qPCR) for the detection of Helicobacter pylori infection and the identification of clarithromycin-resistant strains in children.
A gastric biopsy-based qPCR for the detection of H pylori infection and the identification of clarithromycin-resistant strains in children was evaluated in 62 children with infection and 341 children without infection. H pylori infection was considered by the "reference method" when culture was positive for both histology and rapid urease test (RUT). Results were compared with those obtained using the qPCR.
The reference method versus H pylori qPCR positivity showed 95% confidence interval sensitivity 100% versus 100%, specificity 93.2% (86.9-99.4) versus 100%, positive predictive value 59.7% (47.4-71.9) versus 100%, negative predictive value 100% versus 100%, and, finally, test accuracy of 59.6% (47.3-71.8) versus 100%. Sixty-two children were found to be H pylori positive, based on the qPCR results. Among those, 31 children had both positive qPCR and culture with concordant antimicrobial susceptibility testing results, whereas 31 children had negative culture and positive qPCR. The qPCR showed a bacterial load ≥10 copies per milliliter when culture, histology, and RUT were all positive (29/31 children) versus <10 copies per milliliter when culture, histology, and RUT were all negative (25/31 children). Grades 2 and 3 histological gastritis were associated with a bacterial load ≥10 copies per milliliter for 28/35 of children versus 27/27 of grade 0 to 1 <10 copies per milliliter.
H pylori qPCR positivity is a more precise test than the routine culture, histology, RUT alone and allows detecting low bacterial loads.
本研究旨在评估基于胃活检的定量实时聚合酶链反应（qPCR）在检测儿童幽门螺杆菌感染及鉴定克拉霉素耐药菌株方面的实用性。
对62例感染儿童和341例未感染儿童进行了基于胃活检的qPCR检测，以检测幽门螺杆菌感染并鉴定克拉霉素耐药菌株。当组织学和快速尿素酶试验（RUT）培养均为阳性时，采用“参考方法”判定幽门螺杆菌感染。将结果与qPCR检测结果进行比较。
参考方法与幽门螺杆菌qPCR阳性率比较，95%置信区间敏感性分别为100%对100%，特异性分别为93.2%（86.9 - 99.4）对100%，阳性预测值分别为59.7%（47.4 - 71.9）对100%，阴性预测值分别为100%对100%，最终检测准确性分别为59.6%（47.3 - 71.8）对100%。根据qPCR结果，62例儿童被发现幽门螺杆菌阳性。其中，31例儿童qPCR和培养均为阳性，抗菌药敏试验结果一致，而31例儿童培养阴性但qPCR阳性。当培养、组织学和RUT均为阳性时（29/31例儿童），qPCR显示细菌载量≥每毫升10拷贝，而当培养、组织学和RUT均为阴性时（25/31例儿童），细菌载量<每毫升10拷贝。2级和3级组织学胃炎与细菌载量≥每毫升10拷贝相关，35例儿童中有28例如此，而0至1级27例儿童中27例细菌载量<每毫升10拷贝。
幽门螺杆菌qPCR阳性检测比常规培养、单独的组织学检查、RUT更精确，且能检测到低细菌载量。
