Data from: Effects of prior exposure to antibiotics on bacterial adaptation to phages

Understanding adaptation to complex environments requires information
about how exposure to one selection pressure affects adaptation to others.
For bacteria, antibiotics and viral parasites (phages) are two of the most
common selection pressures and are both relevant for treatment of
bacterial infections: increasing antibiotic resistance is generating
significant interest in using phages in addition or as an alternative to
antibiotics. However, we lack knowledge of how exposure to antibiotics
affects bacterial responses to phages. Specifically, it is unclear how the
negative effects of antibiotics on bacterial population growth combine
with any possible mutagenic effects or physiological responses to
influence adaptation to other stressors such as phages, and how this net
effect varies with antibiotic concentration. Here, we experimentally
addressed the effect of pre-exposure to a wide range of antibiotic
concentrations on bacterial responses to phages. Across 10 antibiotics, we
found a strong association between their effects on bacterial population
size and subsequent population growth in the presence of phages (which in
these conditions indicates phage-resistance evolution). We detected some
evidence of mutagenesis among populations treated with fluoroquinolones,
quinolones and β-lactams at sub-lethal doses, but these effects were small
and not consistent across phage treatments. These results show that,
although stressors such as antibiotics can boost adaptation to other
stressors at low concentrations, these effects are weak compared to the
effect of reduced population growth at inhibitory concentrations, which in
our experiments strongly reduced the likelihood of subsequent
phage-resistance evolution.