TABLE 3.

Numbers of ampicillin resistance genes (bla_TEM), expressed as percentages of the respective genomic DNA of the sample

Day	Ampicillin group						P1A recombinant β-lactamase group						Ampicillin plus P1A recombinant β-lactamase group
	n	Mean	SEM	Min	Max	Prevalence	n	Mean	SEM	Min	Max	Prevalence	n	Mean	SEM	Min	Max	Prevalence
Baseline	12	0	0	0	0.0006	1/12	12	0.0006	0.0006	0	0.0068	3/12	12	0.001	0.0007	0	0.0086	3/12
Day 3	12	11.642a,b	8.8986	0	107.49	8/12	12	0	0	0	0.0004	1/12	12	0.0014b	0.0005	0	0.0047	5/12
Day 4	11	7.8243b	6.5669	0	74.085	5/11	12	0	0	0	0	0/12	12	0.0005b	0.0004	0	0.0043	2/12
Day 5	11	6.2559a,b	5.5761	0	61.888	6/11	12	0	0	0	0.0004	1/12	12	0.0081b	0.0066	0	0.0795	2/12
Day 12	12	0.2392a	0.2273	0	2.7377	6/12	12	0.0007	0.0006	0	0.0074	2/12	12	0.0084	0.0052	0	0.0569	3/12

^aThere were statistically significant increases on day 3 (P < 0.008), day 5 (P < 0.03), and day 12 (P < 0.03).

^bThere were statistically significant differences between the groups receiving ampicillin and ampicillin plus P1A recombinant β-lactamase on day 3 (P < 0.02), day 4 (P < 0.01), and day 5 (P < 0.01).