Anaerobic culture conditions favor biofilm-like phenotypes inPseudomonas aeruginosaisolates from patients with cystic fibrosis

Abstract

Pseudomonas aeruginosa causes chronic infections in the lungs of cystic fibrosis (CF) individuals and remains the leading cause of morbidity and mortality associated with the disease. Biofilm growth and phenotypic diversification are factors thought to contribute to this organism's persistence. Most studies have focused on laboratory isolates such as strain PAO1, and there are relatively few reports characterizing the properties of CF strains, especially under decreased oxygen conditions such as occur in the CF lung. This study compared the phenotypic and functional properties of P. aeruginosa from chronically infected CF adults with those of strain PAO1 and other clinical non-CF isolates under aerobic and anaerobic culture conditions. The CF isolates overall displayed a reduced ability to form biofilms in standard in vitro short-term models. They also grew more slowly in culture, and exhibited decreased adherence to glass and decreased motilities (swimming, swarming and twitching). All of these characteristics were markedly accentuated by anaerobic growth conditions. Moreover, the CF strain phenotypes were not readily reversed by culture manipulations designed to encourage planktonic growth. The CF strains were thus inherently different from strain PAO1 and most of the other non-CF clinical P. aeruginosa isolates tested. In vitro models used to research CF isolate biofilm growth need to take the above properties of these strains into account.

Vitamin B 12 -Mediated Restoration of Defective Anaerobic Growth Leads to Reduced Biofilm Formation in Pseudomonas aeruginosa

“…Of note, it was clearly demonstrated that the oxygen potential was decreased inside this thick mucous layer (56). Importantly, the results of previous studies by our group and others have revealed that P. aeruginosa, when grown by anaerobic respiration, forms robust biofilms (29,57,60). These data further implicate the clinical relevance of the biofilm mode of bacterial growth inside the mucous airway of CF patients.…”

The sensor kinase PhoQ mediates virulence in Pseudomonas aeruginosa

“…Thus, it seems likely that the biofilm defect in this strain was multi-factorial, given the large number of genes differentially regulated in the phoQ mutant. As P. aeruginosa growth in the cystic fibrosis lung has been proposed to be biofilm-like (Garcia-Medina et al, 2005;O'May et al, 2006) this PhoQ-dependent adaptation may help protect the bacteria from the host. If true, this may explain why the phoQ mutant, deficient in biofilm formation, was deficient in survival in the rat lung.…”

Bovine Lactoferrin Inhibits the Efficiency of Invasion of Respiratory A549 Cells of Different Iron-Regulated Morphological Forms of Pseudomonas Aeruginosa and Burkholderia Cenocepacia

“…Interestingly, it has been recently reported that biofilm produced by strains of P. aeruginosa and B. cenocepacia is favoured by environmental stimuli, including oxygen deficiency and iron availability (3,18). With regard to iron, the concentration of iron and Lf in damaged CF respiratory tissues is high if compared to that of healthy controls (4)(5)19).…”