Mookerjee Subham, Batabyal Prasenjit, Halder Madhumanti, Palit Anup
Division of Bacteriology, National Institute of Cholera & Enteric Diseases (Indian Council of Medical Research), P-33, Scheme-XM, CIT Road, Beliaghata, Kolkata 700 010, India.
Division of Bacteriology, National Institute of Cholera & Enteric Diseases (Indian Council of Medical Research), P-33, Scheme-XM, CIT Road, Beliaghata, Kolkata 700 010, India.
J Virol Methods. 2014 Nov;208:115-8. doi: 10.1016/j.jviromet.2014.07.036. Epub 2014 Aug 12.
Conventional procedures for qualitative assessment of coliphage are time consuming multiple step approach for achieving results. A modified and rapid technique has been introduced for determination of coliphage contamination among potable water sources during water borne outbreaks. During December 2013, 40 water samples from different potable water sources, were received for water quality analyses, from a jaundice affected Municipality of West Bengal, India. Altogether, 30% water samples were contaminated with coliform (1-20 cfu/ml) and 5% with E. coli (2-5 cfu/ml). Among post-outbreak samples, preponderance of coliform has decreased (1-4 cfu/ml) with total absence of E. coli. While standard technique has detected 55% outbreak samples with coliphage contamination, modified technique revealed that 80%, double than that of bacteriological identification rate, were contaminated with coliphages (4-20 pfu/10 ml). However, post-outbreak samples were detected with 1-5 pfu/10 ml coliphages among 20% samples. Coliphage detection rate through modified technique was nearly double (50%) than that of standard technique (27.5%). In few samples (with coliform load of 10-100 cfu/ml), while modified technique could detect coliphages among six samples (10-20 pfu/10 ml), standard protocol failed to detect coliphage in any of them. An easy, rapid and accurate modified technique has thereby been implemented for coliphage assessment from water samples. Coliform free water does not always signify pathogen free potable water and it is demonstrated that coliphage is a more reliable 'biomarker' to ascertain contamination level in potable water.
传统的大肠杆菌噬菌体定性评估程序是一种耗时的多步骤方法才能得出结果。一种经过改进的快速技术已被引入，用于在水源性疾病暴发期间测定饮用水源中的大肠杆菌噬菌体污染情况。2013年12月，从印度西孟加拉邦一个受黄疸影响的市政当局接收了40份来自不同饮用水源的水样进行水质分析。总共，30%的水样被大肠菌群污染（1 - 20 cfu/ml），5%被大肠杆菌污染（2 - 5 cfu/ml）。在暴发后的样本中，大肠菌群的优势度有所下降（1 - 4 cfu/ml），且完全没有大肠杆菌。虽然标准技术检测出55%的暴发样本被大肠杆菌噬菌体污染，但改进技术显示，80%的样本被大肠杆菌噬菌体污染（4 - 20 pfu/10 ml），是细菌学鉴定率的两倍。然而，在暴发后的样本中，20%的样本检测到1 - 5 pfu/10 ml的大肠杆菌噬菌体。通过改进技术的大肠杆菌噬菌体检测率几乎是标准技术（27.5%）的两倍（50%）。在少数样本（大肠菌群载量为10 - 100 cfu/ml）中，改进技术能在6个样本中检测到大肠杆菌噬菌体（10 - 20 pfu/10 ml），而标准方法在任何样本中都未能检测到大肠杆菌噬菌体。因此，一种简便、快速且准确的改进技术已被用于水样中大肠杆菌噬菌体的评估。无大肠菌群的水并不总是意味着饮用水无病原体，并且已证明大肠杆菌噬菌体是确定饮用水污染水平更可靠的“生物标志物”。
