Bacteriophages

Ernest Hankin was a British bacteriologist in India in the 1890s studying malaria and cholera. In 1896, he reported that there was something in the Ganges and Jumma rivers that exerted an antibacterial effect against cholera, an effect that continued even after the river waters were passed through a porcelain filter, which held back bacteria. He theorized that this substance was responsible for limiting the spread of the cholera epidemic but proceeded no further in studying this mysterious, invisible substance.

During the early 1900s, the English bacteriologist Frederick Twort was engaged in experiments growing bacteria in an artificial media and noted that some bacteria were killed by an unknown agent, which he designated an “essential substance.” This substance passed through porcelain filters and required bacteria for growth; he thought that it was possibly a virus. His report, published in 1915, was largely ignored for decades. Further work was interrupted by World War I and the lack of funding.

Félix d’Hérelle was a French Canadian microbiologist working at the Pasteur Institute in Paris. As did Twort, d’Hérelle observed the effects of an “invisible antagonist microbe . . . of the dysentery bacillus” that passed through a porcelain filter. He recognized that he had discovered a virus he dubbed a bacteriophage (“bacteria eater”), or simply phage, which he reported in 1917. Although he appeared to be cognizant of Twort’s prior finding, he failed to adequately acknowledge it and largely claimed credit for the discovery. Sensing its antibacterial potential, in 1919, d’Hérelle tested phage in a Paris children’s hospital for the treatment of dysentery and was later involved with establishing a commercial laboratory that produced five different phage preparations as treatments against different bacterial infections.

A bacteriophage (or phage) is a virus that infects bacteria. The phage consists of a capsid head, which encloses its DNA, and a protein tail with fibers by which the phage attaches to a bacterium.

The initial enthusiasm for phages—bacterial viruses that selectively attach to one or a few bacterial hosts and kill them by lysis (destruction by dissolution)—as antibacterial agents waned after the introduction of antibiotics in the 1940s. Interest was renewed in the 1990s when drug-resistant bacteria emerged. Phages continue to be used to treat bacterial infections in Russia and Eastern Europe and experimentally as model systems to study multiplication of viruses.