Selective antimicrobials were used to increase the sensitivity of the assay for detecting resistant E. coli strains among a mix of resistant and susceptible strains within the stool sample.
Melittin-selected bacteria did not survive significantly better than the ancestral population, but there was significantly more variance in this group than in the rest of the data set together (F-test, F = 2.48, df = 8, 64, P < 0.05), suggesting a more diverse mix of resistant and nonresistant clones in this inoculum than in those in other treatments.
Mapping of resistance was approached by mixing the resistant and susceptible genomes followed by selection for resistance after one round of backcrosses.
Campylobacter strains were isolated using standard FDA methodology and also by a modified method that included FQ-supplemented agar medium to identify resistant strains among a mix of susceptible and resistant strains.
The ciprofloxacin supplement enabled the authors to identify FQ-resistant Campylobacter isolates from among a mix of susceptible and resistant strains.
Assuming free mixing of drug-susceptible and drug-resistant capsids and relative abundances that reflect the ratio of their genomes, the data argue that about twenty subunits, or one third, of the capsid proteins must be drug-susceptible to poison the complex.
Compared with monocultures of susceptible or less resilient species, mixing more resistant or resilient species with less susceptible and less resilient species can reduce damage or lessen the reduction in ecosystem function following some biotic disturbances.
In making a case against products spiked with antibacterials, he explained: "Like antibiotics, antibacterials can alter the mix of bacteria; they simultaneously kill susceptible bacteria and promote the growth of resistant strains.
The dynamics of resistant alleles is essentially driven by their genetic dominance, by the degree of host-population mixing, and by the selective pressure exerted by drugs.
Many isolated cases of resistant virus have been found.
