Why in News:

• A study commissioned by the Union Water Resources Ministry to probe the “unique properties” of the Ganga found that the river water contains a significantly higher proportion of organisms with antibacterial properties.

Background:

• The study, ‘Assessment of Water Quality and Sediment To Understand Special Properties of River Ganga,’ began in 2016 and was conducted by the Nagpur-based National Environmental Engineering and Research Institute (NEERI), a CSIR lab. The NEERI team was tasked with assessing the water quality for “radiological, microbiological and biological” parameters in the Bhagirathi (a feeder river of the Ganga) and the Ganga at 20 sampling stations.
• As part of the assessment, five pathogenic species of bacteria (Escherichia, Enterobacter, Salmonella, Shigella, Vibrio) were selected and isolated from the Ganga, Yamuna and the Narmada and their numbers compared with the bacteriophages present in the river water. Because bacteriophages are a kind of virus that kill bacteria, they are frequently found in proximity to each other.

Why Bacteriophages For Removal of Fecal Coliform?

• The Ganges is a lifeline to millions of people in India and the backbone of spiritual life for the country’s Hindu majority. Many believe the river is self-cleansing and has healing powers. Indeed, its water has demonstrated bactericidal activity (the ability to kill bacteria). And although this mystery is still unfolding, it appears to be related to bacteriophages (or phages). And these viruses that infect and kill bacteria could provide a useful alternative to antibiotics in the form of phage therapy.
• Known as the national river of India, the Ganges originates in the western Himalayas and flows to Bangladesh. The river has great spiritual significance to Hindus, who worship it as the goddess Ganga. Its water, popularly called “Ganga Jal”, is considered sacred and is used in many religious rituals.
• From a scientific perspective, the mysterious claim that the Ganges possesses self-cleansing and healing properties is particularly interesting. In fact, the river has been shown to have antibacterial properties and it can retain high amounts of dissolved oxygen, even in extremely polluted conditions.
• As early as 1896, the British bacteriologist Ernest Hankin studied the bactericidal properties of Ganges water. He found that colonies of cholera bacteria that thrived in tap water quickly died in Ganges water. He pursued his experiment by using boiled Ganges water and filtered Ganges water. To his surprise, while the filtered water continued to show an antibacterial effect, the boiled water did not. This clearly indicated that the factor responsible for the water’s bactericidal properties was heat labile (altered by heat) but not not filterable, at least not with the porcelain Pasteur filters Hankin used in his experiment.
• Two decades later, a Canadian microbiologist identified the factor that may explain the mystery of the Ganges. In 1916, Felix d’Herelle was working at the Institute Pasteur in Paris when he discovered phages. Phages are composed of proteins that trap genetic material. They also exhibit properties—difficult to filter and heat labile—that correspond perfectly to what Hankin had observed in Ganges water.
• This suggests the Ganges is heavily populated with phages. They are essentially harmless to humans because they are highly strain specific. For example, phages that infect the cholera bacterium can only infect the cholera bacterium and no other bacteria. Of course, the fact these phages often target bacteria that cause deadly diseases is an added bonus.
• Phages are also a potential tool for treating diseases caused by bacteria. In particular, their specificity is something antibiotics do not possess. In other words, unlike antibiotics, phages can neatly kill the pathogen without harming the natural flora also present in the body (like the lactobacilli in your gut, which aid digestion). The development of phage therapy was attempted in the United States during the early 20th century. However, it was discontinued because of a limited understanding of phages, as well as the arrival of cheaper antibiotics. Today, phage therapy is once again being researched at a time when antibiotic resistance is becoming a major concern, many strains of bacteria have become resistant to antibiotics because of the misuse or overuse of the antibiotics themselves. Therefore, the potential of phage therapy as a replacement for antibiotics is very promising.
• From the Ganges’ longstanding reputation for self-cleansing to a potential solution for antibiotic resistance, phages and phage therapy bridge the gap between an ancient belief and modern medicine