Supplementary Material for: Relative Strengths and Regulation of Different Promoter-Associated Sequences for Various blaSHV Genes and Their Relationships to β-Lactam Resistance
<p><b><i>Aims:</i></b> This work investigated the relative strengths of different <i>bla</i><sub>SHV</sub> promoter-associated sequences and their regulation function in <i>bla</i><sub>SHV</sub> expression and β-lactam resistance. <b><i>Methods:</i></b> Recombinant plasmids with the promoter-associated sequences (P-W, P-S, P-IS, and P-WPD), <i>tac</i> promoter, and combined fragments of promoter and <i>bla</i><sub>SHV</sub> were separately constructed and transformed into <i>Escherichia coli</i>
DH5α. The relative strengths of the promoters indicated by the
intensities of green fluorescent protein and the mRNA expression levels
of <i>bla</i><sub>SHV</sub> were compared. The minimum inhibitory concentration and extended spectrum β-lactamase phenotypes were evaluated. <b><i>Results:</i></b> The relative strengths were ranked as P-<i>tac</i>
> P-WPD > P-IS > P-S > P-W. The mRNA expression and
β-lactam resistance levels of the different promoter-associated sequence
groups were generally consistent with the strength rank, but the extent
of <i>gfp</i> and <i>bla</i><sub>SHV</sub> mRNA levels varied
significantly in each group. The β-lactam resistance levels were
inconsistent with the strength rank in certain <i>bla</i><sub>SHV</sub> groups. In relation to the different promoter-associated sequences,<i> bla</i><sub>SHV-ESBLs</sub> displayed significantly different change modes of β-lactam resistance compared with <i>bla</i><sub>SHV-non-ESBLs</sub>. <b><i>Conclusion:</i></b> The mRNA expression and β-lactam resistance of the <i>bla</i><sub>SHV</sub>
showed consistencies and inconsistencies with the strengths of the
promoter-associated sequences. The mechanisms accounting for these
discrepancies need further investigation.</p
