Serratia has dark history in region / Army test in 1950 may have changed microbial ecology

Chronicle graphic by John Blanchard Chronicle graphic by John Blanchard Image 1 of / 1 Caption Close Serratia has dark history in region / Army test in 1950 may have changed microbial ecology 1 / 1 Back to Gallery

Serratia is a bacterium that some doctors and residents of the Bay Area have been familiar with for many years.

In 1950, government officials believed that serratia did not cause disease. That belief was later used as a justification for a secret post-World War II Army experiment that became a notorious disaster tale about the microbe.

The Army used serratia to test whether enemy agents could launch a biological warfare attack on a port city such as San Francisco from a location miles offshore.

For six days in late September 1950, a small military vessel near San Francisco sprayed a huge cloud of serratia particles into the air while the weather favored dispersal.

Then the Army went looking to find out where it landed. Serratia is known for forming bright red colonies when a soil or water sample is streaked on a culture medium -- a property that made it ideal for the bio-warfare experiment.

Army tests showed that the bacterial cloud had exposed hundreds of thousands of people in a broad swath of Bay Area communities including Sausalito, Albany, Berkeley, Oakland, San Leandro, San Francisco, Daly City and Colma, according to reports that later were declassified. Soon after the spraying, 11 people came down with hard-to-treat infections at the old Stanford University Hospital in San Francisco. By November, one man had died. Edward Nevin, 75, a retired Pacific Gas and Electric Co. worker recovering from a prostate operation, had succumbed to an infection with Serratia marcescens that attacked his heart valves.

The outbreak was so unusual that the Stanford doctors wrote it up for a medical journal. But the medics and Nevin's relatives didn't find out about the Army experiment for nearly 26 years, when a series of secret military experiments came to light.

The Chronicle's David Perlman, who reported on the revelations in 1976, found no evidence that the Army had alerted health authorities before it blanketed the region with bacteria. As the news surfaced, doctors started wondering whether the Army experiment that seeded the Bay Area with serratia two decades earlier might be responsible for heart valve infections then cropping up as well as serious infections seen among intravenous drug users in the '60s and '70s, said Dr. Lee Riley, a professor of infectious disease at UC Berkeley.

Before the 1950 experiment, serratia was not a common environmental bacteria in the Bay Area nor did it frequently cause hospital infections, Riley said.

Some people now speculate that descendants of the Army germs are still causing infections here today, he said. The secret bio-warfare test might have permanently changed the microbial ecology of the region, the theory goes. But to prove it, researchers would need to take a DNA fingerprint of the Army strain for comparison with today's microbes.

In 2001, Serratia marcescens surfaced again as the culprit behind another fatal public health crisis in the Bay Area. Patients were coming down with a painful, hard-to-treat form of meningitis. Public health experts traced the infection to Doc's Pharmacy in Walnut Creek, which mixed some of its own drug products, a legal practice.

At Doc's, investigators found numerous sources of potential contamination -- some stemming from lapses in sterile procedures others from a bubbling tropical fish tank -- in the area where the drug formulas were handled. Among the preparations Doc's had sold was a form of cortisone injected into the spines of dozens of patients with back pain.

One of those patients, a healthy, 47-year-old Concord man named George Stahl, died the day after his injection. At first, doctors believed that the death was due to a burst blood vessel. It wasn't discovered until his autopsy that he had died from a massive serratia infection.

In the meantime, more patients had received the contaminated shots. Doctors raced to identify and treat them. In the end, of the 38 people dosed with antibiotics, three people died and 10 were hospitalized.

Serratia marcescens: History of trouble

The bacteria behind the loss of half this year's U.S. flu vaccine supply is Serratia marcescens, whose characteristic red colonies are shown here under the microscope.

1950: In a secret germ warfare experiment, the Army sprays a vast cloud of Serratiamarcescens over the Bay Area from a vessel in waters off San Francisco. The bacteria blanketed the city and surrounding communities in a circle from Sausalito through the East Bay to Colma.

1950: Shortly after the spraying, 11 patients at the old Stanford University Hospital in San Francisco develop unusually tough infections, and one dies. Serratia destroyed theheart valves of Edward Nevin, 75.

1976: The Army experiment is made public. Nevin's son Edward Nevin Jr. learns his father's death may have been caused by the secret test. Doctors wonder whether the Army germs established a microbial population that caused other infections in the 1960s and1970s.

2001: Meningitis outbreak after Serratia marcescens contaminates spinal injections prepared by Doc's Pharmacy in Walnut Creek. Three die and 10 hospitalized among the 38 treated.

2004: Emeryville biotechnology firm Chiron Corp.'s stock dives when its entire store of flu vaccine, made in England, is declared unsafe due to contamination with Serratia marcescens.

Sources: Michigan State University Communication Technology Lab, MicrobeZoo, Project. Shirley Owens and Catherine McGowan; text by Bernadette Tansey