Kanamycin

The in vitro antimicrobial activity tests of methanolic extracts from the SR and RW against three species of fungi (Aspergillus niger, Alternaria alternata, and Penicillium chrysogenum, ATCC 53346, 8741, and 20044) and two species of bacteria (Pseudomonas aeroginosa and Bacillus sp., ATCC 27813 and 15970) were performed using a previously reported method [57 (link)].
Antimicrobial activity assessment of the industrially obtained lavender essential oil samples was performed in vitro on the following microorganisms: Non-pathogenic Gram-positive and Gram-negative strains of Bacillus subtilis NCNM BB-01 (ATCC 33608) and Pseudomonas fluorescens NCNM-PFB-01 (ATCC 25323), phytopathogenic strains of Xanthomonas campestris NCNM BX-01 (ATCC 53196), Erwinia amylovora NCNM BE-01 (ATCC 29780), E. carotovora NCNM BE-03 (ATCC 15713), and fungus strains of Candida utilis NCNM Y-22 (ATCC 44638) and Saccharomyces cerevisiae NCNM Y-20 (ATCC 4117) following a method described elsewhere [58 ].
The compounds Caspofungin and Kanamycin, both from Liofilchem (Roseto degli Abruzzi, Italy), were used as standards for antifungal and antibacterial activity tests.

The antibiotic susceptibilities of three probiotic candidates were assayed using the minimum inhibitory concentration (MIC) test strip method. Nine antibiotic strips were used for testing the bacterial strains, namely, ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, streptomycin, tetracycline, and vancomycin (Liofilchem, Abruzzi, Italy). The bacteria were grown for 18 h at 37 °C in MRS medium. The cells were harvested via centrifugation at 3470× g for 5 min, washed twice with PBS (pH 7.0), and resuspended in PBS to a McFarland turbidity of 0.5. The cell suspensions were inoculated on BHI agar using swabs. The plates were dried for 15 min, and the MIC test strips were placed on the agar surface according to the manufacturer’s instructions. The plates were then incubated at 37 °C, and the results were assessed after 20 h of inoculation, according to the European Food Safety Authority (EFSA) guidelines [23 (link)].

The determination of bacterial sensitivity to selected antibiotics was performed according to the guidelines of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The method was slightly modified to adapt to the tested strain.
Bacterial culture of Lpb. plantarum DB2, grown in MRS broth, was separated from the medium by centrifugation at 6440× g for 10 min and resuspended in sterile water, with OD values adjusted to 0.5 ± 0.05. The cell suspension was applied to MRS agar plates by uniformly swabbing a cotton swab, previously immersed in the suspension, in three directions. After inoculation, discs of the tested antibiotics (Liofilchem S.r.l., Roseto degli Abruzzi, Italy) were placed on the inoculated MRS agar. The plates were then incubated at 37 °C, and after 24 h, the appearance of inhibition zones was observed, indicating the sensitivity of the tested strain to the antibiotic.
In this study, the sensitivity of lactic acid bacteria isolate DB2 to the following antibiotics was investigated: ampicillin (10 µg), erythromycin (15 µg), gentamicin (10 µg), kanamycin (30 µg), clindamycin (10 µg), chloramphenicol (10 µg), streptomycin (10 µg), tetracycline (30 µg), and vancomycin (30 µg) (Liofilchem S.r.l., Roseto degli Abruzzi, Italy).