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Updated: Oct 11, 2025
Automated, High-Throughput Detection of Bacterial Adherence to Host Cells
Published on: September 17, 2021
Evaluation of the relative expression of genes associated with adherence after different hours of co-culture between
Aluminé S Fessia1, Liliana M Odierno2
1Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Abstract:
Streptococcus uberis is an environmental pathogen associated with subclinical and clinical IMI in both lactating and non-lactating cows. RC19 strain was isolated from a cow with subclinical mastitis, qualitatively classified as moderate biofilm producer in Todd Hewitt medium (THB), and it showed a high value of the adhered bacteria (CFU/ml). Hence, the aims of this study were (a) to determine ability to adhere to and internalize into epithelial cells MAC-T for 1, 2 and 3 h, (b) to evaluate the relative expression of adherence-associated genes from co-cultures of S. uberis with MAC-T cells at 1, 2 and 3 h. We hypothesized that upon contact with bovine mammary epithelial cells, S. uberis upregulates adherence-associated genes encoding adhesins, which enable it a higher adherence to and/or internalization into host cells. Four to six genes increased their R with regard to the control after initial contact with MAC-T cells (group 1) at 1, 2 and 3 h. The highest value of R was observed at 2 h after co-culture between RC19 and MAC-T cells.
Insights
Streptococcus uberis, a mastitis-causing pathogen, increases its adherence and internalization into bovine mammary cells by upregulating specific genes. This occurs within hours of contact, highlighting a rapid response mechanism.
Area of Science:
- Veterinary Microbiology
- Bovine Mastitis Pathogenesis
- Molecular Biology
Background:
- Streptococcus uberis is a significant environmental pathogen causing intramammary infections (IMI) in dairy cows.
- The RC19 strain of S. uberis, isolated from subclinical mastitis, exhibits moderate biofilm production and high bacterial adhesion.
- Understanding bacterial-host cell interactions is crucial for managing mastitis.
Purpose of the Study:
- To investigate the adherence and internalization capabilities of S. uberis RC19 into MAC-T bovine mammary epithelial cells.
- To evaluate the gene expression of adherence-associated factors in S. uberis during co-culture with MAC-T cells.
- To test the hypothesis that S. uberis upregulates adhesin-encoding genes upon contact with host cells.
Main Methods:
- Co-culturing S. uberis RC19 with MAC-T cells for 1, 2, and 3 hours.
- Quantifying bacterial adherence and internalization using colony-forming units (CFU/ml).
- Measuring the relative expression of adherence-associated genes using RT-qPCR.
Main Results:
- S. uberis demonstrated adherence to and internalization into MAC-T cells over a 3-hour period.
- The relative expression of four to six adherence-associated genes increased significantly after initial contact with MAC-T cells.
- Peak gene expression was observed at the 2-hour mark of co-culture.
Conclusions:
- Streptococcus uberis rapidly upregulates adherence-associated genes upon interaction with bovine mammary epithelial cells.
- This upregulation likely contributes to enhanced bacterial adherence and/or internalization, facilitating host cell colonization.
- Findings provide insights into the molecular mechanisms underlying S. uberis mastitis pathogenesis.
