Microbial Pathogenicity and Molecular Epidemiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X 1314, Alice 5700, South Africa.
Acta Trop. 2010 Oct;116(1):68-73. doi: 10.1016/j.actatropica.2010.05.011. Epub 2010 Jun 8.
Clinical response to Helicobacter pylori infection may be determined by specific virulence-associated genotypes which varies geographically. The aim of this study was to investigate the diversity of putative virulence markers of H. pylori; cagA, vacA and iceA in the Eastern Cape Province of South Africa. One hundred H. pylori strains obtained from dyspeptic patients were used. Gastric biopsies were obtained from 254 dyspeptic patients. H. pylori was cultured and strains were studied. Bacterial genotypes cagA, vacA (s and m subtypes) and iceA were analysed by PCR using specific primers. CagA was identified in 90% of the strains investigated. Fifty-eight of the 100 strains had the vacA signal sequence genotype s1 and 26 had subtype s2. Combined vacA s1/s2 was detected in 16 of the strains. VacA middle region analysis showed that 8 (8%) strains were m1 while 50 were m2. Combined vacA m1/m2 was detected in 36 of the strains. s1m2 (20%) and s2m2 (20%) genotypes were the most common allelic combinations of the vacA gene among the strains. Multiple vacA genotypes were detected in this study. Twenty-six percent of the strains identified had both iceA1 and iceA2. All our strains tested positive for the ureC (glmM) gene. This study reveals a high prevalence of vacA, cagA and iceA2.
临床对幽门螺杆菌感染的反应可能由特定的毒力相关基因型决定，而这些基因型在地理上存在差异。本研究旨在调查南非东开普省幽门螺杆菌的潜在毒力标记物 cagA、vacA 和 iceA 的多样性。从消化不良患者中获得了 100 株幽门螺杆菌菌株。从 254 名消化不良患者中获取胃活检样本。培养幽门螺杆菌并研究菌株。使用特定引物通过 PCR 分析细菌基因型 cagA、vacA（s 和 m 亚型）和 iceA。在所研究的菌株中，90%鉴定出 cagA。100 株菌株中有 58 株具有 vacA 信号序列基因型 s1，26 株具有亚型 s2。16 株菌株中检测到 vacA s1/s2 的组合。 vacA 中部区域分析显示，8（8%）株为 m1，50 株为 m2。36 株菌株中检测到 vacA m1/m2 的组合。s1m2（20%）和 s2m2（20%）基因型是菌株中 vacA 基因最常见的等位基因组合。本研究中检测到多种 vacA 基因型。26%的鉴定菌株同时具有 iceA1 和 iceA2。我们所有的菌株均检测到 ureC（glmM）基因呈阳性。本研究显示 vacA、cagA 和 iceA2 的流行率很高。
