Growth conditions affect biofilms of Staphylococcus aureus producing mastitis: Contribution of MALDI-TOF-MS to strain characterization

CÁCERES, MARÍA EMILIA; LEDESMA, MARTÍN MANUEL; LOMBARTE SERRAT, ANDREA; VAY, CARLOS; SORDELLI, DANIEL OSCAR; GIACOMODONATO, MÓNICA NANCY; BUZZOLA, FERNANDA ROXANA

Current Research in Microbial Sciences

Elsevier

Año: 2021 vol. 2

2666-5174

Bovine mastitis is a disease of dairy cattle prevalent throughout the world that causes alterations in the qualityand composition of milk, compromising technological performance. Staphylococcus aureus is one of the mostimportant pathogens that produce clinical, subclinical, and chronic mastitis. Biofilms are considered a virulencefactor necessary for the survival of S. aureus in the mammary gland. Its zoonotic potential is important not onlyfor the dairy industry sector but also for public health. This study aimed to evaluate the effect of differentgrowing culture conditions on the biofilm formation of S. aureus isolated from mastitis and to test the MALDITOF-MS?s ability to discriminate among different biofilm formation levels. Fluids commonly found in the dairyenvironment were incorporated to approach the pathogen?s behavior in natural surroundings. PIA productionwas also evaluated. All strains were able to form high biofilms in TSB, TSBg, and milk. Milk changed the behaviorof some strains which formed more biofilms in this medium than in TSBg. The free iron medium CTSBg and milkwhey inhibited the biofilm formation of the most strains. MALDI-TOF-MS performance was an excellent tool todiscriminate between high, moderate, and low biofilm producers strains of S. aureus in each media, confirmingthe results of crystal violet assay. PIA production was variable among the strains and showed a media-dependentbehavior. Our data highlights the importance of considering the growing conditions that mimic the natural onesto the study of biofilm formation in vitro.