Another question, still unanswered, regards the modes by which antibiotic resistance in water may be relevant for human health. Because antibiotic resistance is harbored and transferred by bacteria, a better understanding of the bacterial diversity and ecology may bring interesting insights into the modes of resistance dissemination from and into humans. This approach is now possible because numerous studies conducted worldwide have explored the bacterial diversity in water habitats over the last decades. In parallel, the human microbiome project has stimulated the thorough characterization of the diversity of bacteria that permanently or transiently can colonize the human body. The combination of both datasets may bring interesting information for the discussion of antibiotic resistance transmission from water to humans and vice versa.