TABLE 1.

In vitro antimicrobial activities of catheters^a

Microorganism	Inoculum	Segment	Zone of inhibition (mm)		Pb
			CS1 catheter	CS2 catheter
S. aureus	106	H	17.7 ± 2.21	16.3 ± 0.14	0.047
	106	V	16.3 ± 1.40	16.4 ± 1.67	0.906
	108	H	16.5 ± 1.60	15.2 ± 0.33	0.019
	108	V	15.5 ± 1.10	15.0 ± 0.77	0.239
S. epidermidis	106	H	18.4 ± 2.24	17.9 ± 1.81	0.497
	106	V	17.4 ± 1.80	16.7 ± 1.14	0.311
	108	H	17.7 ± 1.93	16.4 ± 1.06	0.073
	108	V	16.3 ± 1.62	15.4 ± 0.80	0.087
E. faecalis	106	H	14.4 ± 1.10	12.3 ± 1.44	0.0003
	106	V	13.5 ± 0.87	12.7 ± 0.73	0.014
	108	H	11.8 ± 0.92	11.1 ± 1.44	0.209
	108	V	11.7 ± 0.51	10.8 ± 0.70	0.003
P. aeruginosa	106	H	16.0 ± 0.71	14.4 ± 1.77	0.012
	106	V	14.2 ± 1.23	13.8 ± 1.79	0.473
	108	H	13.9 ± 2.0	13.1 ± 2.30	0.353
	108	V	13.0 ± 2.0	12.3 ± 2.61	0.451
E. cloacae	106	H	9.6 ± 2.13	8.2 ± 0.75	0.050
	106	V	9.2 ± 1.05	8.1 ± 0.55	0.006
	108	H	9.4 ± 1.83	8.4 ± 0.80	0.084
	108	V	9.2 ± 1.10	8.6 ± 0.55	0.102
C. albicans	106	H	13.5 ± 1.29	13.0 ± 1.33	0.323
	106	V	12.8 ± 0.94	12.4 ± 1.35	0.441
	108	H	12.2 ± 0.61	11.2 ± 1.04	0.011
	108	V	11.0 ± 0.53	10.3 ± 0.67	0.006

^aThe activities are presented as those produced after 24 h by horizontal (H) or vertical (V) segments of the commercially available and the experimental catheter on agar plates inoculated with a suspension of 10⁶ or 10⁸ microorganisms/ml. Each value represents the mean ± standard deviation for 12 segments. 

^bTwo-sample t test. Boldface numbers indicate statistically significant differences.