It's well known that antibiotics can disrupt our gut bacteria. But when mosquitoes snack on blood laced with antibiotics, the same can happen to their microbiome. And that depletion of gut bacteria actually increases mosquitoes' susceptibility to the malaria parasite. Meaning they may be more likely to host and then spread the disease-causing protozoan. That's according to a study in the journal Nature Communications. [Mathilde Gendrin et al, Antibiotics in ingested human blood affect the mosquito microbiota and capacity to transmit malaria]

Researchers fed mosquitoes the blood of children infected with the malaria parasite. They added a penicillin-streptomycin antibiotic cocktail to some samples, and a control solution to others. Turns out the mosquitoes that sucked the blood doped with antibiotics were more likely to pick up the parasite. And those mosquitoes appeared to gain some benefit from the antibiotics too—they lived longer and had more offspring than the other mosquitoes in the tests. So these commonly used antibiotics made the insects a more powerful vector for malaria.

Some antibiotics, of course, do inhibit malaria transmission. Doxycycline, for example, is sometimes taken as a malaria prophylactic. 

"Different antibiotics may have different impacts. Which could translate into an opposite effect than what we demonstrated in the paper." Study author George Christophides, of Imperial College London. 

He says this interaction is especially worth considering for patients with malaria as well as tuberculosis or HIV—because treatment of those conditions can involve receiving antibiotics for months. "TB and HIV prevalence in malaria-endemic countries is huge. So if all these people are taking antibiotics, we must know what they do on malaria transmission." Christophides and his colleagues are now investigating those connections—to make sure certain antibiotics don't turn the mosquito into a whole new kind of 'superbug.'

—Christopher Intagliata

[The above text is a transcript of this podcast.]

[Scientific American is part of Nature Publishing Group.]