Effects of metronidazole on growth of Gardnerella vaginalis ATCC 14018, probiotic Lactobacillus rhamnosus GR-1 and vaginal isolate Lactobacillus plantarum KCA

Figures & data

Table I.  Vaginally defined medium + 0.5% proteose peptone (VDMP).

Component	100 ml	1000 ml	Final concentration
Part I
NaCl	0.35 g	3.5 g	0.06 M
KCl	0.15 g	1.5 g	0.20 M
K2HPO4	0.17 g	1.7 g	0.01 M
Dextrose	1.08 g	10.8 g	0.06 M
Cysteine HCl	0.05 g	0.5 g	0.003 M
Proteose peptone	0.5 g	5 g	0.5%
Part II
1. Glycogen	2.0 ml	20.0 ml	0.1%
2. Mucin type 1-S (Sigma M3895)	2.0 ml	20.0 ml	0.025%
3. Tween 20	1.0 ml	10.0 ml	0.02%
4. Urea	0.125 ml	1.25 ml	0.05%
5. Vitamin K	0.1 ml	1.0 ml	0.0001%
6. Hemin	0.1 ml	1.0 ml	0.0005%
7. Albumin (BSA)	4.0 ml	40.0 ml	0.2%
8. MgSO4	0.5 ml	5.0 ml	0.03%
9. NaHCO3	0.1 ml	1.0 ml	0.004%

Figure 1.  Growth curve kinetics of 10% overnight broth culture of G. vaginalis, L. rhamnosus GR-1, and L. plantarum KCA in VDMP.

Figure 2.  Growth stimulation of L. rhamnosus GR-1 in 64 µg/ml and 256 µg/ml metronidazole. Note the growth stimulation of L. rhamnosus GR-1 between 0 and 10 h of incubation at 64 µg/ml of metronidazole compared with 0 µg/ml.

Figure 3.  Growth of L. plantarum KCA in metronidazole.

Figure 4.  Comparative growth inhibition of G. vaginalis, L. rhamnosus GR-1, and L. plantarum KCA in metronidazole.

Table II.  Percentage of growth inhibition of lactobacilli in different concentrations of metronidazole in the presence of vaginally defined medium with peptone.

	Metronidazole concentrations (µg/ml)
Tested strains	64	128	256	512	1000	2000	3000	4000	5000	6000	7000	8000
GR-1	* + 3	0.4	* + 2	5.1	7.4	27.3	51.8	71.5	79.1	82.5	83.4	86.5
KCA	6.9	16.5	4.6	4.6	13.3	45.4	55.9	68.9	77.9	80.8	83.7	84.8.
G. vag	* + 0.2	* + 0.2	1.5	9.5	49.3	63.7	72.2	76.7	80.1	80.2	83.1	84.1

GR-1, Lactobacillus rhamnosus GR-1; KCA, Lactobacillus plantarum KCA; G. vag, Gardnerella vaginalis.

*Growth stimulation (percentage mean optical density values above the mean control).