FIG 3.

Quantification of total and viable cells (in DNA copies/mL) using oil-enveloped bacteria, a metal bath, and a DNA kit to analyze the V. cholerae VBNC state in an aquatic environment. (A to C) DNA copies/mL were measured using oil-enveloped bacteria, a metal bath, and a DNA kit to analyze total and viable cells. Total cell counts were obtained without PMA treatment, and viable cell counts were obtained after PMA treatment. The dotted line represents the qPCR lower limit of detection, and the dashed line represents the ddPCR lower limit of detection. (D) Live/dead staining of cells in the V. cholerae VBNC state in an aquatic environment (scale bar = 20 μm). Viable cells, which are stained only with SYTO9, appear green; dead bacteria appear red.