Trade‐off between antibiotic resistance and biological fitness in Acinetobacter sp. strain DR1

Abstract

Rifampicin, a bactericidal antibiotic drug, is routinely used to make an environmental recipient selective in laboratory-conjugation experiments. We noticed, inadvertently, that the rifampicin-resistant Acinetobacter sp. strain DR1, a recently discovered hexadecane-degrading environmental isolate, exhibited a substantial loss of quorum sensing signalling. The domesticated ampicillin-resistant strain, DR1, evidenced more dramatic phenotypic changes than were observed in the rifampicin-resistant cells: a complete loss of quorum sensing, a loss in swimming and swarming motilities, poor fimbrial expression, increased rigidity in membrane fatty acid composition and reduced hexadecane degradation capability. Interestingly, the motility of strain DR1 grown adjacent to a streptomycin-producing Streptomyces griceus was permanently abrogated, where this change was heritable and other phenotypic changes could not be detected. In this study, we have reported for the first time that the in situ acquisition of antibiotic resistance may reduce biological fitness, including losses in the production of quorum sensing signals, motility and substrate utilization, and each antibiotic is associated with different degrees of phenotypic and genetic alterations. Our data also suggested that the domestication of environmental isolates should be approached with caution, as there are phenotypic variations in antibiotic-resistant cells that might not be noticeable unless all possible phenotypic assays are conducted.

Regulatory Activities of Four ArsR Proteins in Agrobacterium tumefaciens 5A

“…E. coli was grown with 50 g/ml Km, 20 g/ml Gen, or 20 g/ml Tc, as required. Constructs were mobilized into A. tumefaciens strains by conjugation with E. coli S17-1 (20,30).…”

“…Bacterial growth was monitored via measurements of the culture optical density by use of a SpectraMax microtiter plate reader (Molecular Devices, CA). Plasmid isolation, gel electrophoresis, transformation, PCR amplification of DNA, and reporter gene assays were conducted as previously described (20,30). When required, the MMNH 4 agar medium was supplemented with 500 g/ml kanamycin (Km) for selection and maintenance of reporter constructs derived from pLSP-KT2lacZ or with 80 g/ml gentamicin (Gen), 20 g/ml tetracycline (Tc), or 15% sucrose to select for/against pJQ200SK for the generation of deletion mutations (see below).…”

Complete Genome Sequence of the Diesel-Degrading Acinetobacter sp. Strain DR1

“…strain DR1 was isolated from the soil of rice paddies, located in Deok-So (Korea University Agricultural Station), in the Kyonggi province of South Korea. Strain DR1 is capable of utilizing aliphatic hydrocarbons and diesel oil (5). Similarly to A. baylyi ADP1, this strain is also competent for natural transformation.…”

“…There are 6 rRNA operons with a 16S, tRNA-Ile, tRNAAla, 23S, 5S organization. The genes studied previously were clearly identified via genome sequencing (4,5,6). The availability of the complete genome sequence of Acinetobacter sp.…”

A design-constraint trade-off underpins the diversity in ecologically important traits in species Escherichia coli

“…Most such studies have focused on trade-offs in plants and animals, whereas the operation of trade-offs has been much less systematically studied with microorganisms. This is unfortunate because in the examples using bacteria and phages, it is clear that microbes are much more amenable to the analysis of not just the effects but also the potential molecular causes of trade-offs (De Paepe and Taddei, 2006;Jessup and Bohannan, 2008;Mroczkowska and Barlow, 2008;Tree et al, 2008;Lang et al, 2009;Lee et al, 2009;Kang and Park, 2010;De Paepe et al, 2011;Taylor and Buckling, 2011). Here, we identify mutually exclusive traits in Escherichia coli to define an ecological trade-off between self-protection and growth affinity in species-wide terms as well as in molecular detail.…”