Scientists have found dangerous drug-resistant ¡°superbacteria¡± off beaches in Rio de Janeiro that will host Olympic swimming events and in a lagoon where rowing and canoe athletes will compete when the games start Aug. 5.

The findings from two unpublished academic studies concern Rio¡¯s most popular spots for tourists and greatly increase the areas known to be infected by the microbes normally found only in hospitals.

They also heighten concerns that Rio¡¯s sewage-infested waterways are unsafe.