In vitro assessment of the probiotic potential of lactobacilli isolated from Minas artisanal cheese produced in the Araxá region, Minas Gerais state, Brazil

Abstract

Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.

Probiotic Characteristics of Lactobacillus brevis KT38-3 Isolated from an Artisanal Tulum Cheese

“…In our previous study, the supernatant obtained from the L. brevis KT16-2 strain was found to have a broader antimicrobial activity spectrum, including activity against M-R S. epidermidis and M&V-R S. warneri ( Kunduhoglu and Hacioglu, 2021 ). Silva et al (2019) determined that the L. brevis A6, B16 and E35 strains produce bacteriocin-like antimicrobial peptides against Escherichia coli , Enterococcus faecalis , L. monocytogenes, Salmonella Tyhimurium and Shigella flexneri . However, Fonseca et al (2021) reported that the L. brevis CCMA 1284 strain had no antimicrobial effect on any indicator test bacteria such as E. coli CDC 055, B. cereus ATCC 14579, S. aureus ATCC 5674 and L. monocytogenes ATCC 19117.…”

“…1 ). Results from studies on the antibiotic sensitivity of the different L. brevis strains showed that the sensitivity was strain-specific ( Fang et al, 2018 ; Fonseca et al, 2021 ; Jamaly et al, 2011 ; Pavli et al, 2016 ; Silva et al, 2019 ; Somashekaraiah et al, 2019 ). However, it must be shown genotypically whether they carry transferable antibiotic resistance genes or not.…”

“…As a result, it was determined that L. brevis KT38-3 was sensitive to all tested antibiotics except streptomycin (I), erythromycin (I), gentamicin (I) and nalidixic acid (R) (Figure 2). Results from studies on the antibiotic sensitivity of the different L. brevis strains showed that the sensitivity was strain-specific (Jamaly et al, 2011;Pavli et al, 2016;Fang et al, 2018;Silva et al, 2019;Somashekaraiah et al, 2019;Fonseca et al, 2021). However, it must be shown genotypically whether they carry transferable antibiotic resistance genes or not.…”

Antagonistic activity of lactic acid bacteria isolated from Minas artisanal cheeses against Brucella abortus

“…A total of 18 LAB (Table 1) and three B. abortus strains were used in this study. LAB strains were isolated from Minas artisanal cheeses produced in three regions (Canastra, Campos das Vertentes, and Araxá) located in Minas Gerais, Brazil (Castro et al, 2016;Luiz et al, 2016;Resende et al, 2011;Sales, 2015;Sant'anna et al, 2017), and the strains were selected based on their inhibitory potential against some bacterial pathogens, as assessed by previous studies using spot-on-lawn antagonism tests (Andrade et al, 2014;Costa et al, 2013;Sant'anna et al, 2017;Silva et al, 2019). B. abortus reference strains 2308 and 544 (ATCC 23448) (Miranda et al, 2015;Poester et al, 2006) and B. abortus field strain 2683 (biovar 3, isolated from milk) (Dorneles et al, 2014) were used as an indicator of bacteria in antimicrobial activity tests.…”

“…E. coli ATCC 25922 (Andrade et al, 2014;Oliveira et al, 2018;Sant'anna et al, 2017;Silva et al, 2019) was used as a susceptible control. It was grown on MacConkey agar (BD) at 37°C for 24 h. The colonies were resuspended in PBS until an OD of 0.08−0.13, corresponding to 10 8 UFC/mL.…”