A Time Course Study of Production of Virulence Factors by Biofilms of Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is an epitome of opportunistic pathogens. It is the third most common pathogen associated with hospital acquired catheter associated urinary tract infections (CAUTIs). This pathogen forms biofilms on the surface of indwelling catheters which are resistant to antimicrobial agents as well as to host defense mechanisms leading to chronicity and recurrence of infections. In the present study, elaboration of virulence factors by immature and mature biofilm cells of P. aeruginosa was assessed in vitro. It was observed that with increase in time period of biofilm generation from 1 to 4 day (immature biofilms) there was increase in elaboration of majority of virulence traits. However 5 day old biofilms (mature biofilms) were least producers of all the virulence determinants which continued till 7 th day. Implications of these findings in relation to urinary tract infections caused by biofilms of P. aeruginosa have been discussed.

Prototype Development of the Intelligent Hydrogel Wound Dressing and Its Efficacy in the Detection of Model Pathogenic Wound Biofilms

“…A time course analysis of in vitro P. aeruginosa biofilms previously showed increased secretion of all virulence factors as biofilms matured up to day 4. 39,40 A significant dressing response therefore was believed to be triggered by increased production of virulence factors associated with actively growing biofilms. In contrast to S. aureus, the response elicited by P. aeruginosa biofilms was correlated with the age of biofilms, with the strongest response triggered by the oldest biofilms (Figure S2).…”

“…Except for 24 h growth showing a relatively sparse surface coverage by biofilms, the MDR appeared to display higher levels of biofilm formation between 48 and 72 h as assessed subjectively by CLSM visualization (Figure 8). As the secretion of virulence factors was closely related to the healthy growing condition of biofilm, 39,40 this could explain the enhanced dressing response by 72 h dynamic biofilm over the colony biofilm of the same species (Figure 9). However, the exact levels of biofilm formed per unit surface area in the distinct models were not calculated, and it also remains probable that the differences observed are predominantly a function of biofilm density achievable in each system.…”

Surveillance of Fluoroquinolone-Resistant Clinical Isolates of <i>Pseudomonas aeruginosa</i>

“…P. aeruginosa typically infects injured, burned, immune deficient, or immunocompromised patients and causes a variety of infections. The bacterium has various virulence determinants, such as adhesins [3], toxins [4], capsules [5], and biofilms [6], and is also frequently resistant to many commonly used antibiotics [7]. Though many strains of P. aeruginosa are susceptible to cephalosporins, carbenicillin, gentamicin, tobramycin, colistin, polymyxin, and fluoroquinolones, strains resistant to those antibiotics are increasing in medical care facilities and isolation of the multidrug-resistant strain have been reported [8][9][10][11][12].…”