| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1125-1 | ||||
Resumo:Lactic acid bacteria (LAB) are important microorganisms for food industries, as they can present technological properties for various applications, including starter cultures, adjuncts, and, some cases, as potential probiotics. Such properties allow the processing and manufacture of differentiated products in texture, flavor and aroma, which confers quality and appreciation, in addition to bioprotective effects. However, these bacteria may acquire the ability to produce substances and metabolites harmful to human health as a result of transfer and/or gene recombination. The aim of this study was to characterize the safety aspects of 38 LAB isolated from food matrices in the region of Sicily, Italy, through phenotypic tests related to their virulence profile, as well as the investigation of antibiotic resistance. These isolates were submitted to tests of hemolytic activity, coagulase and gelatinase production, and DNase activity. For the investigation of antibiotic resistance, the susceptibility test by the disk diffusion method was employed, in which the most relevant antibiotics were selected: ampicillin (AMP/10 ug), oxacillin (OXA/01 ug), trimethoprim/sulfamethoxazole (SUT/25 ug), imipenem (MPI/10 ug), vancomycin (VAN/05 ug), tetracycline (TET/30 ug), clindamycin (CLI/02 ug), chloramphenicol (CLO/30 ug), rifampicin (RIF/05 ug), and erythromycin (ERI/15 ug). The results were interpreted accordingly indication of European Committee on Antimicrobial Susceptibility testing (EUCAST) and Brazilian Committee on Antimicrobial Susceptibility testing (BrCAST). Staphylococcus aureus subsp. aureus ATCC 25932 was used as control in all phenotypic assays. The findings showed that all tested isolates did not present any of the investigated virulence factors: hemolysis, coagulase, gelatinase, and deoxyribonuclease activities. Considering that these phenotypic tests are important to select cultures with technological properties, further studies are needed, mainly related to genes encoding virulence factors to confirm the safety properties. However, LAB isolates presented different frequencies of resistance to the tested antibiotics: AMP (23.68%), OXA (97.37%), SUT (23.68%), MPI (13.16%), VAN (89.47%), TET (92.10%), CLI (65.79%), CLO (15.79%), RIF (81.58%), and ERI (7.90%). Notably, over 89% of the isolates showed resistance to OXA, VAN, and TET, and more than 80% showed resistance against RIF. It is already well studied that several LAB strains can present an intrinsic resistance to antibiotics like VAN and OXA, and there is a growing concern about the emergence of transferable resistant genes against TET. Although LAB present a history of safe use, attention must be given mainly because certain resistance to specific antibiotics can be accelerated due to the indiscriminate use of these substances, as for example, in animal feed. Therefore, in-depth studies related to the transfer of resistance genes individually for each isolate are necessary in order to guarantee the safety of cultures with technological potential for application in food. Palavras-chave: technological potential, antibiotic resistance, virulence profile Agência de fomento:FAPEMIG, CNPq and CAPES | |||||