Resistance to oxidative stress caused by ceftazidime and piperacillin in a biofilm of Pseudomonas

Abstract

The capacity to form a biofilm was evaluated in Pseudomonas aeruginosa isolated from patients with lung and urinary infections. Adherence, development of microcolonies and slime formation varied in the studied strains. P. aeruginosa P63 isolated from cystic fibrosis (CF) exhibited important microcolony formation with the densest biofilm, and was selected to study the oxidative stress produced with ceftazidime and piperacillin by means of chemiluminescence (CL) in cell suspensions and biofilm. P. aeruginosa strain P63 was compared with P69; both were sensitive to ceftazidime and showed increase of reactive species of oxygen (ROS) in the presence of this antibiotic. P. aeruginosas P69 exhibited resistance to piperacillin and low ROS production, while piperacillin-sensitive strain P63 showed high oxidative stress with this antibiotic. Piperacillin stimulated oxidative stress, increasing ROS production only in the sensitive strain. Higher antibiotic concentrations were necessary to augment ROS in bacteria biofilm than in suspension. Incubation of P63 strain with ceftazidime or piperacillin in the presence of its own extracellular matrix (EM) or sodium alginate stimulated lesser oxidative stress and slower decrease of ROS than in the absence of these polysaccharides. A variant, V(10), obtained from strain P63 showed more sensitivity to the antibiotics than the wild-type, and concomitantly exhibited higher production of ROS in the presence of both the antibiotics studied.

Antioxidative mechanisms protect resistant strains of Staphylococcus aureus against ciprofloxacin oxidative damage

“…In this way, we have demonstrated that ciprofloxacin, ceftazidime, piperacillin and chloramphenicol can generate an increase of superoxide anion in bacterial species with different degrees of defence against oxidative metabolism [5]. Also, a relationship was observed between resistance to oxidative stress and the concomitant resistance to antibiotics in biofilms of different bacteria species [21].…”

Antimicrobial resistance, respiratory tract infections and role of biofilms in lung infections in cystic fibrosis patients

“…During antibiotic treatment, maturation of the biofilm is associated with attenuated oxidative stress [111,112] and reduced lethality by OH - [110]. This reduced susceptibility of mature biofilm may result from the stratified physiology of biofilm [73,113] enabling protection from oxidative stress in populations with low aerobic metabolic activity due to maturation in zones with limited availability of O 2 and nutrients.…”

“…On the other hand formation of ROS in biofilm during antibiotic treatment has long been recognized and includes P. aeruginosa treated with ceftazidime or piperacillin [111,112]and B. cenocepacia treated with tobramycin [90].…”

Selfprotective smart orthopedic implants

“…One major difficulty in treating such infections is inability of the antibiotics to penetrate and destroy the biofilm [75][76][77]. The resistance of the biofilm to antibiotics is hypothesized to be the result of several protective mechanisms including a low diffusion rate within the slime and a decreased metabolic state of bacteria within the biofilm [65,[78][79][80][81][82]. Because of the inability of systemic antibiotics to penetrate biofilms, removal of the implant and delivery of local antibiotics using methylmethacrylate cement is currently considered the gold standard for treatment of periprosthetic infection [83,84].…”