Antimicrobial activity and antibiotic susceptibility of Lactobacillus and Bifidobacterium spp. intended for use as starter and probiotic cultures

Figures & data

Table 1. Lactobacillus and Bifidobacterium strains included in this study and source of isolation.

Strain	Source of isolation
L. bulgaricus: L. b 1; L. b 2; L. b 5; L. b 6; L. b 7E L. plantarum: L. pl 24-4B L. brevis: L. br 1	Home-made yoghurt
L. casei: L. c L-4 L. rhamnosus: L. rh Lio2 L. paracasei: L. parac 4k	Home-made cheese
L. helveticus: L. h N11; L. h N12; L. h 3 L. lactis: L. lc L-14	Yellow cheese whey
L. acidophilus: L. a 10	Plant origin-melon
L. helveticus: L. h AFA	Blue-green algae
L. plantarum: L. pl 24-5D	Pickle
L. plantarum: L. pl 24-2L; L. pl 24-3L	Raw-fermented sausages
L. acidophilus: L. a L-1 L. helveticus: L. h 108 L. rhamnosus: L. rh Lio1 B. longum: B. lg L-1 B. bifidum: B. bf L-2 B. animalis subsp. lactis: B. lc L-3	Baby faeces
L. fermentum: L. f 1	Saliva

Figure 1. Antimicrobial activity of Lactobacillus and Bifidobacterium strains against Staphylococcus aureus NBIMCC 3703: (A) aCFS and nCFS; (B) aCFW and nCFW. *pH values of acid CFSs and acid CFWs.

Figure 2. Antimicrobial activity of Lactobacillus and Bifidobacterium strains against Bacillus cereus NBIMCC 1085: (A) aCFS and nCFS; (B) aCFW and nCFW. *pH values of acid CFSs and acid CFWs.

Figure 3. Antimicrobial activity of Lactobacillus and Bifidobacterium strains against Escherichia coli NBIMCC 3702: (A) aCFS and nCFS; (B) aCFW and nCFW. *pH values of acid CFSs and acid CFWs.

Table 2. MIC (μg/mL) of antimicrobials for Lactobacillus and Bifidobacterium strains determined by E-test®.

	Susceptibility to the following antibiotic MIC (μg/mL)
Tested strain	AM	VM	GM	KM	SM	EM	CM	TC	CL
EFSA L. acidophilus group*	1	2	16	64	16	1	1	4	4
L. a L-1	0.125	1	12	>256^R	6	0.75	4^R	0.75	1.5
L. a 10	0.19	0.19	0.25	8	0.50	0.032	0.19	0.75	1.5
EFSA obligate homofermentative*	1	2	16	16	16	1	1	4	4
L. h N11	1	0.50	2	4	6	0.25	0.50	1	3
L. h N12	0.094	0.094	1.5	12	0.50	0.064	0.125	1	2
L. h AFA	0.047	0.094	0.094	12	0.50	0.064	0.19	0.19	2
L. h 108	0.032	0.38	0.75	12	0.75	0.023	0.50	0.75	0.032
L. h 3	0.023	1	2	16	4	0.50	0.75	1	2
L. b 7E	0.19	0.25	0.75	6	12	<0.016	0.032	0.125	4
L. b 1	0.023	0.38	1	8	4	<0.016	0.023	0.50	4
L. b 2	0.047	0.38	0.75	6	4	< 0.016	0.023	0.50	3
L. b 5	0.064	0.75	1.5	6	4	<0.016	0.016	0.50	3
L. b 6	0.125	0.38	1	8	6	< 0.016	0.023	0.25	4
L. lc L-14	0.094	0.25	2	12	12	<0.016	0.047	0.75	0.094
EFSA L. casei/paracasei*	4	n.r.	32	64	64	1	1	4	4
L. c L-4	0.19	>256	<0.016	12	4	0.19	2^R	1	8^R
L. parac 4k	0.50	>256	0.19	32	32	0.125	<0.016	<0.016	3
EFSA L. rhamnosus*	4	n.r.	16	64	32	1	1	8	4
L. rh Lio1	0.75	>256	0.75	12	>1024^R	1	0.75	0.50	4
L. rh Lio2	0.19	>256	<0.016	4	4	0.023	0.19	0.19	3
EFSA L. plantarum/pentosus*	2	n.r.	16	64	n.r.	1	2	32	8
L. pl 24-2L	0.38	>256	3	32	24	0.75	2	16	4
L. pl 24-3L	0.75	>256	4	48	32	1	2	24	4
L. pl 24-5D	1	>256	4	48	64	0.75	0.75	24	6
L. pl 24-4B	0.75	>256	3	48	48	0.75	1	16	4
EFSA obligate heterofermentative*	2	n.r.	16	32	64	1	1	8	4
L. br 1	0.38	>256	2	64^R	16	0.19	12^R	6	4
L. f 1	0.023	>256	0.38	12	4	0.38	<0.016	0.38	1.5
EFSA Bifidobacterium*	2	2	64	n.r.	128	1	1	8	4
B. lg L-1	<0.016	0.50	2	12	2	0.023	0.023	1	3
B. bf L-2	<0.016	0.38	2	8	2	0.023	0.023	0.75	2
B. lc L-3	0.047	0.75	3	12	4	0.064	0.50	1	3

Note: AM – ampicillin, VM – vancomycin, GM – gentamicin, KM – kanamycin, SM – streptomycin, EM – erythromycin, CM – clindamycin, TC – tetracycline, CL – chloramphenicol.

*Strains with MIC higher than the breakpoints are considered as resistant (R) according to EFSA.[4].

n.r. – not required.

The bold values are reference values given by EFSA. [4] and that is why they are visually emphasized. This would allow easier comparison with the values obtained for the tested strains.

Guidance on the assessment of bacterial susceptibility to antimicrobials of human and veterinary importance. EFSA J. 2012;10(6):2740–2750.

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