Biofilm and Pathogenesis-Related Proteins in the Foodborne P. fluorescens ITEM 17298 With Distinctive Phenotypes During Cold Storage

Abstract

In food chain, Pseudomonas spp. cause spoilage by reducing shelf life of fresh products, especially during cold storage, with a high economic burden for industries. However, recent studies have shed new light on health risks occurring when they colonize immunocompromised patient tissues. Likewise to P. aeruginosa, they exhibit antibiotic resistance and biofilm formation, responsible for their spread and persistence in the environment. Biofilm formation might be induced by environmental stresses, such as temperature fluctuations causing physiological and metabolic changes exacerbating food spoilage (by protease and pigment synthesis), and the production of adhesion molecules, chemotactic or underestimated virulence factors. In order to provide a new insight into phenotypic biodiversity of Pseudomonas spoilers isolated from cold stored cheese, in this work 19 Pseudomonas spp. were investigated for biofilm, pigments, exopolysaccharide production and motility at low temperature. Only nine strains showed these phenotypic traits and the blue pigmenting cheese strain P. fluorescens ITEM 17298 was the most distinctive. In addition, this strain decreased the survival probability of infected Galleria mellonella larvae, showing, for the first time, a pathogenic potential. Genomic and proteomic analyses performed on the ITEM 17298 planktonic cells treated or not with lactoferrin derived antibiofilm peptides allowed to reveal specific biofilm related-pathways as well as proteins involved in pathogenesis. Indeed, several genes were found related to signaling system by cGMP-dependent protein kinases, cellulose, rhamnolipid and alginate synthesis, antibiotic resistance, adhesion and virulence factors. The proteome of the untreated ITEM 17298, growing at low temperature, showed that most of the proteins associated with biofilm regulation, pigmentation motility, antibiotic resistance and pathogenecity were repressed, or decreased their levels in comparison to that of the untreated cultures. Thus, the results of this work shed light on the complex pathways network allowing psychrotrophic pseudomonads to adapt themselves to

Lactoferrin-Derived Peptides as a Control Strategy against Skinborne Staphylococcal Biofilms

“…According to what was previously shown for gram negative bacteria [30,31], HLF negatively affected biofilm production also by CoN strains; interestingly, MBIC value (2.5 mg/mL) was quite similar (3 mg/mL) to that registered for Pseudomonas spp. after 48 h of incubation in optimal growth medium [30].…”

“…In this perspective, AMPs, with demonstrated antibiofilm activity against Pseudomonas spp. [30,31], were herein assayed against CoP and CoN Staphylococcus biofilm producers. Among all assayed species, some strains belonging to S. epidermidis and S. saprophyticus produced the highest biofilm amount, whilst moderate biofilm amounts were recorded for S. aureus, S. caprae, and S. xylosus, S. epidermidis, and S. saprophyticus species, these being the most occurring species colonizing skin from healthy humans as well as medical implants, urinary catheters, and heart valves [45,46].…”

Genomic Analysis of Three Cheese-Borne Pseudomonas lactis with Biofilm and Spoilage-Associated Behavior

“…Amending the previous description of Pseudomonas spp. ITEM 17298 [ 22 , 24 ], this isolate should be correctly classified as Pseudomonas lactis . Hereinafter, these bacteria will be referred to as P. lactis .…”

“…As widely reported, biofilms are organized structures surrounded by extracellular matrix in which the cells are embedded and protected from the environmental stresses. Recently, biofilms and QS have been suggested as important factors in the deterioration of dairy products, opening new fields of investigation and challenges to counteract spoilage [ 21 , 24 , 51 , 52 ]. In particular, the production of hydrolytic enzymes (extracellular proteases, lipases, glycosidases, and phospholipases) have been demonstrated to be enhanced in QS regulated-biofilms by several bacterial spoilers, including P. fluorescens [ 51 , 52 , 53 ]; thus, innovative antibacterial strategies based on the application of QS inhibitors have been considered promising to prevent food spoilage.…”

“…It has been reported that biofilm plays a role in spoilage by promoting enzyme production and color development [ 21 , 22 ]. Furthermore, biofilm eradication from the dairy environments is generally difficult since they are resistant to common antimicrobial strategies [ 23 , 24 , 25 ] and, thus, they provided a persistent source of contamination.…”