Department of Microbiology, JIPMER, Puducherry, India.
Division of Bacteriology, NICED, Kolkata, West Bengal, India.
J Med Microbiol. 2020 Mar;69(3):372-378. doi: 10.1099/jmm.0.001131.
The emergence of novel strains of O1 El Tor biotype has gained attention due to causing several epidemics around the world. Variant strains have evolved as a result of the acquisition of genes that confer extended virulence and pathogenicity. This study aimed to determine the presence of the most recently emerging Haitian-like genetic traits among the isolates from Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, Southern India. We also wanted to detect the prevalence of the sulfamethoxazole and trimethoprim (SXT) element, which is an integrating conjugative element (ICE) and the antimicrobial resistance genes present in our isolates. Identification of Haitian-specific alleles was done by mismatched amplification mutation assay PCR (MAMA-PCR). The presence of SXT elements was carried out by PCR by detecting and genes. Detection of antibiotic resistance determinant, ) for trimethoprim resistance, for tetracycline resistance and ) for azithromycin resistance were targeted by PCR. The MIC of tetracycline, ciprofloxacin and azithromycin was determined by the E-test method. Of the 95 isolates, 60 % of the isolates were found to carry Haitian-specific alleles of , and gene 100 % of the isolates were found to carry SXT elements. All the isolates harboured the four conserved genes of the SXT element, except one which had only , , genes. About 99 % harboured and genes. No and macrolide genes were detected. We observed a progressive increase in the MIC of azithromycin ranging from 0.75 µg ml to 2 µg ml. None of the isolates were the prototype El Tor biotype. All the isolates were a Haitian variant. The presence of SXT elements across all our isolates and their creeping MIC of azithromycin is a matter of concern. Further testing for other genetic determinants of resistance will be carried out in our future studies.
新型 O1 型 El Tor 生物型的出现引起了全球关注，因为它导致了几次大流行。由于获得了赋予扩展毒力和致病性的基因，变异株已经进化。本研究旨在确定印度南部本地治里贾瓦哈拉尔·尼赫鲁研究生医学教育和研究学院分离株中是否存在最近出现的海地样遗传特征。我们还希望检测磺胺甲恶唑和甲氧苄啶（SXT）元素的流行情况，磺胺甲恶唑和甲氧苄啶是一种整合共轭元件（ICE），以及我们分离株中存在的抗生素耐药基因。通过错配扩增突变检测 PCR（MAMA-PCR）鉴定海地特有的等位基因。通过检测 和 基因，通过 PCR 检测 SXT 元件的存在。通过 PCR 检测对甲氧苄啶耐药的 基因、对四环素耐药的 基因和对阿奇霉素耐药的 基因，以确定抗生素耐药决定因素。通过 E 试验法确定四环素、环丙沙星和阿奇霉素的 MIC。在 95 株分离株中，发现 60%的分离株携带海地特定的 、 和 基因等位基因，100%的分离株携带 SXT 元件。所有分离株均携带 SXT 元件的四个保守基因，除了一个只有 、 、 基因。约 99%的分离株携带 基因和 基因。未检测到 基因和大环内酯基因。我们观察到阿奇霉素 MIC 逐渐增加，范围从 0.75 µg ml 至 2 µg ml。没有分离株是原型 El Tor 生物型。所有分离株均为海地变异株。我们所有分离株均存在 SXT 元件，且其阿奇霉素 MIC 不断增加，这令人担忧。在我们未来的研究中，将进行其他耐药基因遗传决定因素的进一步检测。
