Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns' endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, ...

BACKGROUND AND OBJECTIVES The properties of neuraminidase produced by P. aeruginosa strain PAO1 during growth in a defined medium (BHI) was examined and compared with some neuraminidase features of K. pneumoniae in this investigation. MATERIALS AND METHODS The enzyme was isolated from concentrated culture supernatants of P. aeruginosa which was used in a sensitive fluorometric assay by using ...

Pseudomonas aeruginosa is an opportunistic pathogen that may cause severe infections in humans and other vertebrates. In addition, a human clinical isolate of P. aeruginosa, strain PA14, also causes disease in a variety of nonvertebrate hosts, including plants, Caenorhabditis elegans, and the greater wax moth, Galleria mellonella. This has led to the development of a multihost pathogenesis syst...

Antibodies to the lipopolysaccharide O antigen of Pseudomonas aeruginosa mediate high-level immunity, but protective epitopes have proven to be poorly immunogenic, while nonprotective or minimally protective O-antigen epitopes often elicit the best immune responses. With the goal of developing a broadly protective P. aeruginosa vaccine, we used a gene replacement system based on the Flp recombi...

Quorum sensing (QS) in Pseudomonas aeruginosa regulates the production of many virulence factors and plays an important role in the pathogenesis of P. aeruginosa infection. N-acyl homoserine lactones (AHL) are major QS signal molecules. Recently, a novel AHL-lactonase enzyme, AiiM, has been identified. The aim of this study was to evaluate the effect of AiiM on the virulence of P. aeruginosa in...

The aim of the present study was to elucidate the effect of the macrolide antibiotic azithromycin on Pseudomonas aeruginosa. We studied the susceptibility to azithromycin in P. aeruginosa PAO1 using a killing assay. PAO1 cells at the exponential growth phase were resistant to azithromycin. In contrast, PAO1 cells at the stationary growth phase were sensitive to azithromycin. The divalent cation...

We investigated the regulation of the psbA and pvdA pyoverdine biosynthesis genes, which encode the L-ornithine N(5)-oxygenase homologues in Pseudomonas strain B10 and Pseudomonas aeruginosa PAO1, respectively. We demonstrate that pyoverdine(B10), as the end product of its biosynthetic pathway, is a key participant of the control circuit regulating its own production in Pseudomonas strain B10. ...

The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase that removes the fatty acid side chain from the homoserine lactone (HSL) nucleus of AHL-dependent qu...

Pseudomonas aeruginosa is a leading cause of blinding corneal ulcers worldwide. To determine the role of type III secretion in the pathogenesis of P. aeruginosa keratitis, corneas of C57BL/6 mice were infected with P. aeruginosa strain PAO1 or PAK, which expresses ExoS, ExoT, and ExoY, but not ExoU. PAO1- and PAK-infected corneas developed severe disease with pronounced opacification and rapid ...

The expression of many virulence factors in Pseudomonas aeruginosa is dependent upon environmental conditions, including iron levels, oxygen, temperature, and osmolarity. The virulence of P. aeruginosa PAO1 is influenced by the iron- and oxygen-regulated gene encoding the alternative sigma factor PvdS, which is regulated through the ferric uptake regulator (Fur). We observed that overexpression...