Getting a stomach bug is bad enough. But a new outbreak of salmonella bacteria spread by raw turkey that has sickened nearly 100 people across several US states has a troubling wrinkle to it: The germ at fault is likely also resistant to multiple antibiotics.
On Thursday, the US Centers for Disease Control and Prevention (CDC) reported that between November and 11 July, at least 90 people from 26 states have been infected with the same strain of Salmonella Reading. Forty were hospitalised, though none have died. Many of the people interviewed by the CDC reported they had eaten or exposed themselves to turkey products just before becoming sick. In two cases, the victims said they lived in a household where their pets ate raw turkey pet food.
There doesn’t appear to be a single common source for the outbreak. The same strain was found in a variety of tested raw turkey pet foods, raw turkey products and live turkeys in different states, indicating it might be running wild throughout the turkey industry. Both the CDC and the United States Department of Agriculture have reached out to industry representatives and “asked about steps that they may be taking to reduce Salmonella contamination,” the agency said.
The CDC is cautioning people to wash their hands and cooking areas after handling raw turkey, not to wash raw poultry before cooking it, and to throughly cook their birds. Generally, it recommends not feeding your precious pet any raw food at all.
Most people who catch a nasty strain of Salmonella become sick within 12 to 72 hours of being exposed to it. They experience anywhere from four to seven days of gastrointestinal hell, developing diarrhoea, fever, and stomach cramps. Though it usually doesn’t require urgent treatment like antibiotics, it can rarely become life-threatening if the germ finds its way into the bloodstream and reaches other parts of the body.
Some, but not all, of the samples of the outbreak strain showed signs of resistance to as many as six different antibiotics at once. The antibiotics aren’t regularly used to treat Salmonella in people, so it likely won’t be any harder to fight off than usual. But superbugs can hurt us in other ways.
Even harmless bacteria can loan other disease-causing bacteria their resistance genes through free-moving bits of DNA called plasmids. And there’s ample evidence that the spread of many dangerous resistance genes—including those that provide protection against the last resort antibiotics we have available for some infections—has been boosted by the use of antibiotics on farms.
The outbreak is possibly also a sign that US farmers are still routinely using antibiotics on livestock, despite a federal mandate that went into effect in 2017 trying to at least slow down the practice.
On 1 January of last year, the US Food and Drug Administration issued new rules that barred the use of antibiotics in livestock as growth promoters. But the rules still allowed farmers to use some antibiotics as a preventative treatment, so long as their use was approved by a veterinarian. A third of the antibiotics included on that list have no limits on how long they could be used, which prompted critics to worry that companies could exploit the loophole to maintain business as usual.
There’s some evidence the rules led to real changes. A 2017 FDA report found that US sales of animal antibiotics dropped 10 per cent in 2016, when the rules were going through their final tweaks. It was the first drop seen since the FDA started collecting data on sales in 2009.
Given this latest outbreak, though, it seems it’s too early to hope that farms won’t continue to be a breeding ground for superbugs.