G6PDH enzymatic activity detected in CM and WCL of the four OC, SIN, NR and T B. clausi strains grown aerobically at 37°C in LB medium to stationary growth phase. CM and bacterial cells were harvested and assayed as described in Materials and Methods. G6PDH activity in CM was compared with that associated with deliberately lysed cell (WCL). The data shown are the means of measurements from three independent experiments. 0.01 units of G6PDH were assayed as a control in each experiment.