Table 1 .

Presence of bacterial growth on each agar plate cultured

	Presence of bacteria
Bottle number	Sample 1	Sample 2	Sample 3	Sample 4	Sample 5	Sample 6
1	Positive	Negative	Negative	Negative
2	Negative	Negative	Negative
3	Negative	Negative	Negative	Negative	Negative
4	Negative	Positive	Negative	Negative	Negative	Negative
5	Negative
6	Negative	Negative
7	Negative	Negative
8	Negative
9	Negative	Negative	Negative	Negative
10	Negative	Negative
11	Negative
12	Negative	Negative	Negative	Negative	Positive	Negative
13	Negative	Negative
14	Negative	Negative	Negative	Positive
15	Negative
16	Negative	Negative
17	Negative	Negative
18	Negative	Negative	Negative	Negative	Negative

Every bottle of chlorhexidine was used a different number of times before being discarded, therefore the number of samples taken from each bottle was different. The blank cells indicate that no further samples were taken from the bottle of that row.