Lactobacillus rhamnosus and Staphylococcus epidermidis in gut microbiota: in vitro antimicrobial resistance

AMB Express

Table 1 Comparative table between the different MIC, IC₅₀ and MBC of Lactobacillus rhamnosus GG, Staphylococcus epidermidis 444 and the co-culture of both strains

	Inhibitory Concentration (IC50)
	Lysozyme (mg/mL)								Oxytetracycline hydrochloride (μg/mL)
	With EDTA				Without EDTA				Without lysozyme-EDTA	With lysozyme-EDTA
	pH2	pH6	pH7.5	pH8.5	pH2	pH6	pH7.5	pH8.5	pH 7.5
L. rhamnosus GG	ND	ND	30	ND	ND	ND	ND	ND	152	90
S. epidermidis 444	ND	22	18	50	ND	ND	26	ND	130	1.22
Co-culture strains	ND	ND	26	ND	ND	ND	ND	ND	ND	10.93
L. rhamnosus GG	ND	ND	80	ND	ND	ND	ND	ND	700	ND
S. epidermidis 444	ND	40	40	80	ND	ND	ND	ND	700	ND
Co-culture strains	ND	ND	80	ND	ND	ND	ND	ND	700	ND

	Minimum Bactericidal Concentration (MBC) at pH 7.5
	lysozyme-EDTA (IC₅₀) (mg/mL)	Oxytetracycline hydrochloride (μg/mL)
L. rhamnosus GG	30	700
S. epidermidis 444	18	700
Co-culture strains	26	700

	Minimal Complete Biofilm Eradication Concentration (MCBEC50) at pH 7.5
	Lysozyme (mg/mL)		Oxytetracycline hydrochloride (μg/mL)
	With EDTA	Without EDTA	Without lysozyme-EDTA	With lysozyme-EDTA
L. rhamnosus GG	50	66	ND	1144
S. epidermidis 444	26	30	ND	24
Co-culture strains	30	ND	ND	1464

ND indicates that MIC, IC₅₀ and MCBEC₅₀ was not detectable.
Different MCBEC₅₀ of Lactobacillus rhamnosus GG, Staphylococcus epidermidis 444 biofilms and the co-culture of both strains were also compared. All tests were performed at pH 7.5