Veterinary researchers use human antibodies to combat virulent bacteria
by Donna Boynton

Researchers at the Cummings School have developed a way to treat the early onset of illnesses caused by a virulent strain of E. coli bacteria.

Infectious disease expert Saul Tzipori has been working for eight years to find a treatment for the E. coli strain that was linked to the recent illnesses caused by bagged spinach. © PAUL KAPTEYN/TELEGRAM & GAZETTE

Dr. Saul Tzipori, an infectious disease expert, and a team of researchers on the Grafton campus have been working for eight years on a human antibody treatment for Escherichia coli 0157, or E. coli 0157.

The treatment is now being produced by Worcester-based Biovest for clinical trials in humans that are expected to take place by spring at Tufts-New England Medical Center. The announcement of the treatment comes at a time when scores of people are recovering from a nationwide outbreak of E. coli 0157 that has been linked to bagged spinach.

E. coli is a common bacteria present in most mammals, including humans, and in avian species. There are five different categories of E. coli, with the most virulent to humans being the 0157 strain, said Tzipori, professor of biomedical sciences. He said that particular strain did not emerge until the mid-1980s, after a fast-food-related outbreak in Oregon and Michigan caused by undercooked hamburger.

This strain of E. coli, though treatable in adults, is more damaging and sometimes fatal in children. E. coli 0157 causes illnesses that first present themselves as diarrhea in adults before progressing to bloody diarrhea. The bloody diarrhea is caused by a toxin produced by the 0157 strain, and it usually takes a person three to seven days to recover, Tzipori said.

“In kids, this is much more devastating,” he noted. In children, the toxin enters the bloodstream and can affect several organs, particularly the kidneys. The strain can cause hemolytic uremic syndrome (HUS), a complication affecting the kidneys, and in some cases, causing death.

However, the recent spinach outbreak severely sickened adults. Reports estimate that 187 got sick, and 97 of those were hospitalized. “This is a huge number by normal standards,” Tzipori said, adding that it is unknown how many of the adults who are fully recovered from the E. coli outbreak will have residual kidney damage that will be discovered later.

Tzipori said the recent outbreak is troubling because this strain of E. coli doesn’t usually sicken adults to the point where hospitalization is required.

Tzipori, who has also received a $25 million, seven-year biodefense contract from the National Institutes of Health to study water- and food-borne diseases, assembled the team of researchers eight years ago to develop a therapy that targets the toxin produced by the 0157 strain of E. coli bacteria. The immune-based therapy borne of the study uses specific human antibodies to target the toxin.

“It really acts like your own vacuum, intercepting the toxin molecules and deactivating them so they won’t affect the kidney or brain,” he said.

In preclinical trials, the antibodies were administered to pigs infected with E. coli strain after the onset of diarrhea to protect against the development of systemic kidney and brain damage. The treatment was successful.

“We believe it is best used when people show up with bloody diarrhea,” Tzipori said. “It won’t prevent the diarrhea, but it will certainly prevent the complications.”

This story is reprinted with permission of the Worcester Telegram & Gazette.