Nandi S, Chakraborti A, Bakshi D K, Rani A, Kumar R, Ganguly N K
Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Lett Appl Microbiol. 2002;35(3):237-41. doi: 10.1046/j.1472-765x.2002.01176.x.
To monitor the presence of various pyrogenic exotoxin genes in strains of Streptococcus pyogenes isolated in India.
METHODS & RESULTS: Isolates recovered from pharyngitis (52) and rheumatic fever (RF)/ rheumatic heart disease (RHD) (8) patients were analysed for the presence of toxin genes, speA, speB and speF, by PCR. The specificity of the products was confirmed by restriction enzyme digestion and Southern hybridization. Among the 60 isolates studied, the incidence of speA, speB and speF were 5(8.3%), 56(93.3%) and 53(88.3%), respectively. The expression of these genes was established in representative isolates by RT-PCR.
Comparative analysis of frequency of the speA, speB and speF genes, among pharyngitis and RF/RHD associated isolates, showed higher incidence in RF/RHD (25%, 100%,100%) as compared to pharyngitis patients (5.8%, 92.3%, 86.5%), respectively. SIGNIFICANCE OF STUDY: The presence of the speA gene, which is usually associated with scarlet fever or toxic shock-like syndrome, within few Indian isolates may be indicative of new virulent strains circulating within the Indian community. High distribution of toxin genes among RF/RHD compared to pharyngitis isolates indicate their possible role in increased virulence.
监测在印度分离出的化脓性链球菌菌株中各种热原性外毒素基因的存在情况。
通过聚合酶链反应（PCR）分析从咽炎患者（52例）和风湿热（RF）/风湿性心脏病（RHD）患者（8例）中分离出的菌株，检测毒素基因speA、speB和speF的存在情况。通过限制性内切酶消化和Southern杂交确认产物的特异性。在所研究的60株菌株中，speA、speB和speF的发生率分别为5株（8.3%）、56株（93.3%）和53株（88.3%）。通过逆转录聚合酶链反应（RT-PCR）在代表性菌株中确定了这些基因的表达。
对咽炎相关菌株和RF/RHD相关菌株中speA、speB和speF基因频率的比较分析显示，与咽炎患者（分别为5.8%、92.3%、86.5%）相比，RF/RHD患者中这些基因的发生率更高（分别为25%、100%、100%）。研究意义：在少数印度菌株中存在通常与猩红热或中毒性休克样综合征相关的speA基因，可能表明印度社区内有新的毒力菌株在传播。与咽炎分离株相比，RF/RHD分离株中毒素基因的高分布表明它们可能在增加毒力方面发挥作用。
