Bacteria thrive on iron, which is why the “barbaric” custom of bloodletting may have worked. From Germ Study Suggests Bloodletting May Work:
University of Chicago microbiologists report Thursday in the journal Science that the staph germ — a leading cause of pneumonia and other infections — fuels itself with iron in a previously unknown way.Early in staph infections, the germs blow open red blood cells. The Chicago researchers found staph then snatches their oxygen- and iron-carrying component, called heme, and discovered the genes that govern the process.
When they weakened those genes, staph no longer sickened worms or mice, said lead researcher Eric P. Skaar. Next step is hunting drugs to block staph’s iron-stealing ability.
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Now derided as a nonsensical if not barbaric custom, bloodletting was abandoned in the mid-20th century after antibiotics were invented.But the mystery persists: “How could a procedure popular for 2,500 years have really been completely worthless?” Rouault asked.
Bloodletting was used for lots of reasons, many that “didn’t make good sense,” she stressed. But, searching old medical texts, she found that starting in 18th-century France, certain physicians advised it only at the start of a high-fever illness. Even in 1942, medicine’s leading English-language textbook advised early bleeding for high-fever pneumonia.