The low levels of fimbriae expression observed may be linked to loss of adhesion to hexadecane droplets, reduced membrane permeability, or diminished motility. Membrane integrity and permeability may play important roles in many bacterial stress responses. Our data demonstrated for the first time that, in addition to the plasmid replication burden, the plasmid-encoded membrane bound efflux pump encoded by tetH gene is important for altering bacterial physiology and phenotypes such as peroxide resistance, membrane permeability, and fimbria expression. Physical incorporation of the efflux pump into the membrane appears to be critical for altering membrane integrity. The efflux pump protein encoded by TetH in pAST2 contains 400 amino acids with an unusual 11 transmembrane domains; most tetracycline efflux pumps, such as TetA, contain 12 transmembrane helices. The TetH protein belongs to the major facilitator superfamily of transporters, which has little specificity. In many bacterial genomes, membrane-transport proteins comprise only 0.1–1.0% of the total proteins, and the expression of many membrane proteins is very low under typical conditions. Our data demonstrated that high expression of the plasmid-encoded TetH altered the physiological status of cells, including hydrogen peroxide resistance, ALK5 Inhibitor II reduction of motility, and altered fimbria expression. Modulation of biological fitness by the plasmid-mediated tetracycline resistance TetH efflux pump may be attributed to the interference of the plasmidencoded membrane-bound tetracycline efflux pump. In conclusion, the significant alteration of bacterial membrane integrity caused by the plasmid-mediated efflux pump affects bacterial phenotype and biological fitness in the environment. Picornaviruses are a family of positive-sense single stranded RNA viruses within the order Picornavirales. They can cause intestinal, respiratory, neurological, cardiac, hepatic, mucocutaneous, and systemic diseases of varying severity in humans and animals. Currently, five different types of IRES element that direct cap-independent translation initiation on the viral RNA to produce the polyprotein have been identified from the primary sequence, secondary structure, location of the initiation codon and activity in different cell types. In most picornaviruses, the polyprotein encoded by the ORF is cleaved into four structural viral particle proteins and seven non structural proteins. PSV infections have been associated with a wide spectrum of symptoms ranging from asymptomatic infection to clinical signs including diarrhea, pneumonia, polioencephalomyelitis, and reproductive disorders. Although PSVs can be important pathogens because of their wide distribution and high prevalence, the near-complete genomic sequences of only three PSV strains have been reported previously; one from the U.K. and two from China. This prompted us to characterize the full-length genetic properties of Korean PSV strains.