Antibiotic resistance, hemolysis and biogenic amine production assessments of Leuconostoc and Weissella isolates for kimchi starter development

- The safety of 23 Leuconostoc and 45 Weissella isolates from kimchi were assessed.
- All strains exhibited intrinsic streptomycin resistance.
- All were sensitive to ampicillin, chloramphenicol, erythromycin, and tetracycline.
- Biogenic amine production was strain-specific.
- Nine W. cibaria strains and two W. confusa strains exhibited α-hemolytic activity.

We assessed the antibiotic resistance, hemolysis, and biogenic amine production of 23 Leuconostoc and 45 Weissella strains from kimchi. Antibiotic resistance was determined using the minimum inhibitory concentration (MIC) test and the disk diffusion method. The results from each method were in agreement, except in the case of penicillin G and gentamicin resistance. Based on the two test results, all strains were susceptible to ampicillin, chloramphenicol, erythromycin, and tetracycline, but resistant to streptomycin. The streptomycin resistance displayed by Weissella species may be attributed to intrinsic factors, as seen in other lactic acid bacteria. All strains were susceptible to penicillin G according to the MIC test results. The breakpoint value of the genera Leuconostoc and Weissella for penicillin G was 2 mg/L. Leuconostoc spp. were susceptible to gentamicin, while 11 of the Weissella isolates exhibited 2-fold MIC values compared with Leuconostoc strains, a finding that could not be ascribed to acquired resistance. We further demonstrated that biogenic amine production is strain-specific, and is more common among Weissella spp. than among Leuconostoc spp. Nine W. cibaria strains and two W. confusa strains exhibited α-hemolytic activity, and no β-hemolysis was observed in any of the isolates.