qPCR EXPRESSION PROFILING OF GENES ENCODING POTENTIAL VIRULENCE FACTORS AND QUORUM SENSING IN Streptococcus uberis BIOFILMS

MOLIVA, MELINA VANESA; PIANZZOLA MARÍA JULIA; MARÍA INÉS SIRI; REINOSO, ELINA BEATRIZ

Congreso; Reunión conjunta SAIB-SAMIGE 2020; 2020

Streptococcus uberis is the main environmental agent causing mastitis in dairy cattle. The pathogenesis is attributed to a combination of extracellular factors and properties such as adherence and biofilm formation. S. uberis infections can be both persistent and resistant to antimicrobial treatment. The goal of the present study was to evaluate the expression levels of two virulence associated genes (sua and hasA/C) and one related to quorum sensing (luxS) and competence (comX) of S. uberis strains growth under planktonic and biofilm conditions at different times. Four S. uberis strains (SU23, SU50, SU150 and SU216), previously characterized according to their ability to produce biofilm were used in this study. Total RNA was isolated from biofilm and planktonic cultures at 24, 48 and 72 h. Relative expression levels of the genes were determined by Relative Quantitative Real Time PCR (qPCR). Glyceraldehyde-3-phosphate dehydrogenase (gapdh) was used as reference gene and the comparative threshold cycle method (2 ?ΔΔCt) was applicated. Results indicated that sua (related to adherence), hasA and hasC (involved in capsule formation) showed a significant increase level expression in the late phase of biofilm formation at 48 h compared with planktonic cultures (p