title: Biofilm production and beta-lactamic resistance in Brazilian Staphylococcus aureus isolates from bovine mastitis.
abstract: Staphylococcus spp. play an important role in the etiology of bovine mastitis. Staphylococcus aureus is considered the most relevant species due to the production of virulence factors such as slime, which is required for biofilm formation. This study aimed to evaluate biofilm production and its possible relation to beta-lactamic resistance in 20 S. aureus isolates from bovine mastitic milk. The isolates were characterized by pheno-genotypic and MALDI TOF-MS assays and tested for genes such as icaA, icaD, bap, agr RNAIII, agr I, agr II, agr III, and agr IV, which are related to slime production and its regulation. Biofilm production in microplates was evaluated considering the intervals determined along the bacterial growth curve. In addition, to determine the most suitable time interval for biofilm analysis, scanning electron microscopy was performed. Furthermore, genes such as mecA and blaZ that are related to beta-lactamic resistance and oxacillin susceptibility were tested. All the studied isolates were biofilm producers and mostly presented icaA and icaD. The Agr type II genes were significantly prevalent. According to the SEM, gradual changes in the bacterial arrangement were observed during biofilm formation along the growth curve phases, and the peak was reached at the stationary phase. In this study, the penicillin resistance was related to the production of beta-lactamase, and the high minimal bactericidal concentration for cefoxitin was possibly associated with biofilm protection. Therefore, further studies are warranted to better understand biofilm formation, possibly contributing to our knowledge about bacterial resistance in vivo.
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Viviane Figueira
authors.initials: VF
authors.lastname: Marques
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Cássia Couto da
authors.initials: CC
authors.lastname: Motta
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Bianca da Silva
authors.initials: BD
authors.lastname: Soares
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Dayanne Araújo de
authors.initials: DA
authors.lastname: Melo
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Instituto de Veterinária (IV), Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Shana de Mattos de Oliveira
authors.initials: SM
authors.lastname: Coelho
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil.
authors.forename: Irene da Silva
authors.initials: ID
authors.lastname: Coelho
authors.affiliation: Instituto Oswaldo Cruz - Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Helene Santos
authors.initials: HS
authors.lastname: Barbosa
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Microbiologia e Imunologia Veterinária, Seropédica, Rio de Janeiro, RJ, Brazil. Electronic address: miliane@ufrrj.br.
authors.forename: Miliane Moreira Soares de
authors.initials: MM
authors.lastname: Souza
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D002417:Cattle; D005260:Female; D056726:Genetic Association Studies; D008414:Mastitis, Bovine / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D020543:Proteome; D040901:Proteomics / Q000379:methods; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D015534:Trans-Activators / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics; D018440:beta-Lactam Resistance
chemical_list: C095698:Agr protein, Staphylococcus aureus; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D020543:Proteome; D015534:Trans-Activators; D037521:Virulence Factors
keywords: Agr types; Antimicrobial resistance; Biofilm; Mastitis