The Basis for Natural Multiresistance to Phage in .

is responsible for long-term infections and is particularly resistant to treatments when hiding inside the extracellular matrix or biofilms. Phage therapy might represent an alternative to antibiotic treatment, but up to 10% of clinical strains appear to resist multiple phages. We investigated the characteristics of clinical strains naturally resistant to phages and compared them to highly susceptible strains.

Investigation of Pseudomonas aeruginosa strain PcyII-10 variants resisting infection by N4-like phage Ab09 in search for genes involved in phage adsorption.

Bacteria and their bacteriophages coexist and coevolve for the benefit of both in a mutualistic association. Multiple mechanisms are used by bacteria to resist phages in a trade-off between survival and maintenance of fitness. In vitro studies allow inquiring into the fate of virus and host in different conditions aimed at mimicking natural environment.

Impact of FiuA Outer Membrane Receptor Polymorphism on the Resistance of toward Peptidoglycan Lipid II-Targeting PaeM Pyocins.

Certain strains produce a homolog of colicin M, namely, PaeM, that specifically inhibits peptidoglycan biosynthesis of susceptible strains by hydrolyzing the lipid II intermediate precursor. Two variants of this pyocin were identified whose sequences mainly differed in the N-terminal protein moiety, i.e.

Recovery and Characterization of Bacteria Resisting Infection by Lytic Bacteriophage.

Bacteria and bacteriophages coexist and coevolve, bacteriophages being obligatory predators exerting an evolutionary pressure on their prey. Mechanisms in action vary depending on the bacterial genomic content and on the regulation of the bacteriophage cycle. To assess the multiplicity of bacterial genes involved in resistance as well as the changes in the bacteriophage interactions with the bacteria, it is necessary to isolate and investigate large numbers of independent resistant variants.

A carrier state is established in Pseudomonas aeruginosa by phage LeviOr01, a newly isolated ssRNA levivirus.

ssRNA bacteriophages are very abundant but poorly studied, particularly in relation to their effect on bacterial evolution. We isolated a new Pseudomonas aeruginosa levivirus, vB_PaeL_PcyII-10_LeviOr01, from hospital waste water. Its genome comprises 3669 nucleotides and encodes four putative proteins.

Fine structure analysis of lipopolysaccharides in bacteriophage-resistant Pseudomonas aeruginosa PAO1 mutants.

Pseudomonas aeruginosa lipopolysaccharides (LPS) serve as primary receptors for many bacteriophages and, consequently, their biosynthesis is frequently affected in phage-resistant mutants. We previously isolated phage-resistant PAO1 mutants using three different phages, and showed that they were affected in the synthesis of LPS. Here we have investigated in detail the effect of mutations in seven genes involved in different steps of the production of core and oligosaccharide chains.

Large Preferred Region for Packaging of Bacterial DNA by phiC725A, a Novel Pseudomonas aeruginosa F116-Like Bacteriophage.

Bacteriophage vB_PaeP_PAO1_phiC725A (short name phiC725A) was isolated following mitomycin C induction of C7-25, a clinical Pseudomonas aeruginosa strain carrying phiC725A as a prophage. The phiC725A genome sequence shows similarity to F116, a P. aeruginosa podovirus capable of generalized transduction.

Complete Genome Sequences of Pseudomonas aeruginosa Phages vB_PaeP_PcyII-10_P3P1 and vB_PaeM_PcyII-10_PII10A.

vB_PaeP_PcyII-10_P3P1 and vB_PaeM_PcyII-10_PII10A are Pseudomonas aeruginosa bacteriophages belonging, respectively, to the Lit1virus genus of the Podoviridae family and the Pbunavirus genus of the Myoviridae family. Their genomes are 72,778 bp and 65,712 bp long, containing 94 and 93 predicted open reading frames, respectively.

Pseudolysogeny and sequential mutations build multiresistance to virulent bacteriophages in Pseudomonas aeruginosa.

Coevolution between bacteriophages (phages) and their prey is the result of mutualistic interactions. Here, we show that pseudolysogeny is a frequent outcome of infection by virulent phages of Pseudomonas aeruginosa and that selection of resistant bacterial mutants is favoured by continuous production of phages. We investigated the frequency and characteristics of P.

Investigation of a Large Collection of Pseudomonas aeruginosa Bacteriophages Collected from a Single Environmental Source in Abidjan, Côte d'Ivoire.

Twenty two distinct bacteriophages were isolated from sewage water from five locations in the city of Abidjan, Côte d'Ivoire over a two-year period, using a collection of Pseudomonas aeruginosa strains with diverse genotypes. The phages were characterized by their virulence spectrum on a panel of selected P. aeruginosa strains from cystic fibrosis patients and by whole genome sequencing.

A novel Pseudomonas aeruginosa bacteriophage, Ab31, a chimera formed from temperate phage PAJU2 and P. putida lytic phage AF: characteristics and mechanism of bacterial resistance.

A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31) is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2.