FIG. 1.

Schematic map of bmeABC in B. fragilis. The main figure consists of a hypothetical operon composed of bmeA (a mexA homolog), bmeB (a mexB homolog), and bmeC (an oprM homolog). A schematic diagram of the insertion-mediated mutagenesis is included. For example, the pGERM recombinant carrying an internal DNA fragment of bmeB (indicated by the black hexagon) is integrated into the recipient by a single homologous recombination event (crossed black lines) to result in FMB271, a disruption mutant of bmeB. Small arrows indicate positions and directions of primers. Abbreviations: ERY^s, erythromycin sensitive; ERY^r, erythromycin resistant; ermG, erythromycin-resistant marker for Bacteroides spp.