Biofilm Formation on Biotic and Abiotic Surfaces in the Presence of Antimicrobials by Escherichia coli Isolates from Cases of Bovine Mastitis

Abstract

Escherichia coli is a highly adaptive microorganism, and its ability to form biofilms under certain conditions can be critical for antimicrobial resistance. The adhesion of four E. coli isolates from bovine mastitis to bovine mammary alveolar (MAC-T) cells, biofilm production on a polystyrene surface, and the expression profiles of the genes fliC, csgA, fimA, and luxS in the presence of enrofloxacin, gentamicin, co-trimoxazole, and ampicillin at half of the MIC were investigated. Increased adhesion of E. coli isolates in the presence of antimicrobials was not observed; however, increased internalization of some isolates was observed by confocal microscopy. All of the antimicrobials induced the formation of biofilms by at least one isolate, whereas enrofloxacin and co-trimoxazole decreased biofilm formation by at least one isolate. Quantitative PCR analysis revealed that all four genes were differentially expressed when bacteria were exposed to subinhibitory concentrations of antimicrobials, with expression altered on the order of 1.5-to 22-fold. However, it was not possible to associate gene expression with induction or reduction of biofilm formation in the presence of the antimicrobials. Taken together, the results demonstrate that antimicrobials could induce biofilm formation by some isolates, in addition to inducing MAC-T cell invasion, a situation that might occur in vivo, potentially resulting in a bacterial reservoir in the udder, which might explain some cases of persistent mastitis in herds.

The Antimicrobial Effect of a Commercial Mixture of Natural Antimicrobials Against Escherichia coli O157:H7

“…EPS plays a key role in the biofilm architecture and provides increased resistance to different types of stresses (e.g. host immune responses, osmotic and oxidative stresses antimicrobial agents) (Hentzer et al 2003;Rivas et al 2010;Silva et al 2014). Quorum sensing (QS) constitutes a global regulatory mechanism for different physiological functions of E. coli as well as for virulence factors including biofilm formation (Sperandio et al 2001).…”

Bergenin Plays an Anti-Inflammatory Role via the Modulation of MAPK and NF-κB Signaling Pathways in a Mouse Model of LPS-Induced Mastitis

“…Mastitis is the inflammation of the mammary gland, caused by infecting pathogenic microorganisms [3,4]. Escherichia coli is the primary gram-negative bacterial pathogen that causes mastitis [5]. E. coli and its toxins may damage mammary epithelial cells and induce the epithelial cells to release inflammatory cytokines, causing an acute, severe inflammatory response [6].…”

Inhibition ofEscherichia coliinvasion into bovine mammary epithelial cells previously infected byMycobacterium aviumsubsp.paratuberculosis

“…Besides the presence of bacteria, it was verified that other factors may influence the process of invasion in mammary cells. Silva et al (2014) verified that the subinhibitory concentrations of antimicrobials in the medium increased the internalization capacity of E. coli isolated from bovine mastitis in MAC-T cells, but did not alter the adhesion. This fact suggests that the internalization process is not necessarily associated with the adherence ability.…”