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Updated: Mar 1, 2026
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR
Published on: November 4, 2016
Host-pathogen interactions in bovine mammary epithelial cells and HeLa cells by Staphylococcus aureus isolated from
Ivana G Castilho1, Stéfani Thais Alves Dantas1, Hélio Langoni2
1Department of Microbiology and Immunology, Institute of Bioscience, São Paulo State University, Botucatu-SP, 18.618-689, Brazil.
Abstract:
Staphylococcus aureus is a common pathogen that causes subclinical bovine mastitis due to several virulence factors. In this study, we analyzed S. aureus isolates collected from the milk of cows with subclinical mastitis that had 8 possible combinations of bap, icaA, and icaD genes, to determine their capacity to produce biofilm on biotic (bovine primary mammary epithelial cells and HeLa cells) and abiotic (polystyrene microplates) surfaces, and their ability to adhere to and invade these cells. We also characterized isolates for microbial surface components recognizing adhesive matrix molecules (MSCRAMM) and agr genes, and for their susceptibility to cefquinome sulfate in the presence of biofilm. All isolates adhered to and invaded both cell types, but invasion indexes were higher in bovine primary mammary epithelial cells. Using tryptic soy broth + 1% glucose on abiotic surfaces, 5 out of 8 isolates were biofilm producers, but only the bap+icaA+icaD+ isolate was positive in Dulbecco's Modified Eagle's medium. The production of biofilm on biotic surfaces occurred only with this isolate and only on HeLa cells, because the invasion index for bovine primary mammary epithelial cells was too high, making it impossible to use these cells in this assay. Of the 5 biofilm producers in tryptic soy broth + 1% glucose, 4 presented with the bap/fnbA/clfA/clfB/eno/fib/ebpS combination, and all were protected from cefquinome sulfate. We found no predominance of any agr group. The high invasive potential of S. aureus made it impossible to observe biofilm in bovine primary mammary epithelial cells, and we concluded that cells with lower invasion rates, such as HeLa cells, were more appropriate for this assay.
Insights
This study shows that Staphylococcus aureus biofilm production in bovine mastitis is gene-dependent and influenced by cell type. HeLa cells are better for studying biofilm formation than bovine mammary cells due to lower invasion rates.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Staphylococcus aureus causes subclinical bovine mastitis.
- Virulence factors contribute to S. aureus pathogenicity.
- Understanding biofilm formation is crucial for mastitis control.
Purpose of the Study:
- Analyze S. aureus isolates from bovine mastitis.
- Determine biofilm production capacity on biotic and abiotic surfaces.
- Assess adherence, invasion, and antibiotic susceptibility.
Main Methods:
- Analyzed 8 S. aureus isolate combinations of bap, icaA, and icaD genes.
- Assessed biofilm production on polystyrene microplates, bovine mammary epithelial cells, and HeLa cells.
- Characterized isolates for MSCRAMM, agr genes, and antibiotic susceptibility.
Main Results:
- All isolates adhered to and invaded both cell types; invasion was higher in bovine cells.
- 5 of 8 isolates produced biofilm on abiotic surfaces; only bap+icaA+icaD+ isolate produced biofilm in DMEM.
- Biofilm production on HeLa cells was observed with the bap+icaA+icaD+ isolate; bovine cells were unsuitable due to high invasion.
- 4 of 5 biofilm producers had specific gene combinations and were protected from cefquinome sulfate.
Conclusions:
- S. aureus exhibits variable biofilm production based on gene combinations and surface type.
- HeLa cells are more suitable than bovine mammary epithelial cells for studying S. aureus biofilm formation due to lower invasion rates.
- Biofilm formation in S. aureus bovine mastitis isolates confers protection against cefquinome sulfate.
