Blogs / 80beats

A new study has shown that salmonella bacteria use a surprising tactic when they attack a mammal’s intestinal system. A small percentage of the bacteria mount a kamikaze mission from which they’ll never return, but which helps allows the rest of the salmonella bacteria to thrive, spreading the infection and ultimately benefiting the species.

Researchers found that in the early stage of an infection, about 15 percent of the salmonella go on a suicide mission, invading the intestinal walls. There, the immune system handily wipes them out. But that also sets off a wider immune response that, while attacking the salmonella within the gut, also wipes out many other micro-organisms. “This inflammation removes many of the competitors, so the second group which waited outside can proliferate,” said [lead researcher] Martin Ackerman [The New York Times].

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Ninety years after the discovery of the first antibiotic, penicillin, researchers have found an entirely new tactic in the fight against bacteria that cause infectious diseases. Instead of hunting for new ways to kill bacteria, researchers have developed a drug, called LED209, that disarms them, preventing them from releasing the toxins that cause illness.

“The sensors in bacteria are waiting for the right signal to initiate the expression of virulent genes,” [said lead researcher] Vanessa Sperandio…. “Using LED209, we blocked those sensing mechanisms and basically tricked the bacteria to not recognize that they were within the host” [Reuters]. The new technique, which has only been demonstrated in mice so far, could be a boon for researchers who are worried about creating more antibiotic-resistant “superbugs.”

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After over 14 weeks of looking, Food and Drug Administration officials investigating the salmonella outbreak finally have something to go on. In a produce distribution plant in McAllen, Texas they discovered a single pepper tainted with the same strain of salmonella, called salmonella Saintpaul, that has sickened over 1,200 people since April.

The FDA inspectors say the bacteria found on the pepper in McAllen is a genetic match with the samples taken from sick patients. But Monday’s discovery, the equivalent of a fingerprint, doesn’t solve the mystery: Authorities still don’t know where the pepper became tainted — on the farm, or in the McAllen, Texas, plant, or at some stop in between, such as a packing house…. Still, “this genetic match is a very important break in the case,” said Dr. David Acheson, the Food and Drug Administration’s food safety chief [AP].

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Consumers may be avoiding summertime’s ripe, juicy tomatoes needlessly. While the Food and Drug Administration (FDA) blamed the broad salmonella outbreak to fresh tomatoes a month ago, it has recently admitted that it might be wrong about the source of the bacterial contamination, which has sickened over 900 people since April. About 1,700 tomatoes have been tested, and none has contained the Salmonella Saintpaul bacterium implicated in the outbreak. Meanwhile, more people have fallen ill [Los Angeles Times].

FDA inspectors are now considering jalapeno and serrano peppers as possible culprits, along with cilantro; all three ingredients are commonly mixed with tomatoes to make fresh salsa. While the public anxiously awaits answers, the produce industry is enraged: U.S. tomato growers say the salmonella scare has already cost them $100 million, and now pepper and cilantro growers may begin to feel the consumer backlash. “We all put public health first, but you don’t casually crush an industry, deprive poor migrant workers of their pay, bankrupt farmers, have consumers throw out food — without triple-checking all these things,” said Jim Prevor, author of the industry blog the Perishable Pundit [Washington Post].

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The slow-rolling salmonella outbreak in several states has finally got health officials seriously alarmed. Today the FDA asked New Mexico and Texas grocery stores, restaurants, hospitals and schools to stop selling and serving the tomatoes that are thought to carry the salmonella bacteria.

Too bad there’s not a parallel outbreak of bad comedy, because somewhere in the Southwest right now, hundreds of thousands of tomatoes are rotting.

The FDA singled out raw red plum, Roma and round red tomatoes as the possible culprits, and also reminded consumers to stay away from fresh salsa made with tomatoes. The agency also issued recommendations that sound not only sensible, but a bit tastier.

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