Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

Lam, Joseph S.; Taylor, Véronique L.; Islam, Salim T.; Hao, Youai; Kocı́ncová, Dana

doi:10.3389/fmicb.2011.00118

Cited by 226 publications

(306 citation statements)

References 172 publications

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“…Mutations in the gene cluster regulating the production of alginate were selected by Ab09, and could reduce the efficiency of infection of all the phages. The wzy, wzz2 and wbpL genes are members of the heteropolymeric O-specific antigen biosynthesis cluster in PAO1 (Lam et al, 2011). Gene migA encodes a rhamnosyltransferase involved in LPS core capping (Poon et al, 2008), whereas wapH and dnpA are known to be involved in the synthesis of LPS (Hansen et al, 2007;Liebens et al, 2014), and pgi encodes a glycosyltransferase (Rocchetta et al, 1999).…”

Section: Resultsmentioning

confidence: 99%

“…Spontaneous mutations responsible for phage resistance are frequently related to alterations in the phage receptor (Hyman & Abedon, 2010;Labrie et al, 2010). In P. aeruginosa, adsorption mutants are principally affected in type IV pili, often used as receptors by podoviruses (Chibeu et al, 2009) and siphoviruses, or in LPS, a major virulence factor (King et al, 2009;Lam et al, 2011) involved in the binding of myoviruses. We and others showed that large chromosomal deletions could be selected in bacteria resistant to single or multiple phages.…”

Section: Introductionmentioning

confidence: 99%

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

Latino

2016

Microbiology

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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. aeruginosa strain PAO1 variants resisting infection by different combinations of virulent phages belonging to four genera. The frequency of resistant bacteria was 10 25 for single phage infection and 10 26 for infections with combinations of two or four phages. The genome of 27 variants was sequenced and the comparison with the genome of the parental PAO1 strain allowed the identification of point mutations or small indels. Four additional variants were characterized by a candidate gene approach. In total, 27 independent mutations were observed affecting 14 genes and a regulatory region. The mutations affected genes involved in biosynthesis of type IV pilus, alginate, LPS and O-antigen. Half of the variants possessed changes in homopolymer tracts responsible for frameshift mutations and these phase variation mutants were shown to be unstable. Eleven double mutants were detected. The presence of free phage DNA was observed in association with exclusion of superinfection in half of the variants and no chromosomal mutation could be found in three of them. Upon further growth of these pseudolysogens, some variants with new chromosomal mutations were recovered, presumably due to continuous evolutionary pressure.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Latino

2016

Microbiology

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“…P. aeruginosa is well known for its ability to cause chronic and extensively drug-resistant infections (1). The outer membrane lipopolysaccharide (LPS) layer is a major virulence factor of P. aeruginosa (2). LPS has been linked to antibiotic resistance and immune evasion.…”

mentioning

confidence: 99%

“…LPS has been linked to antibiotic resistance and immune evasion. Furthermore, LPS is one of the receptors that determines the susceptibility of the bacterium to bacteriophages and pyocins (2)(3)(4). Our ability to control P. aeruginosa infections depends on the availability of accurate typing methods.…”

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confidence: 99%

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Application of Whole-Genome Sequencing Data for O-Specific Antigen Analysis and In Silico Serotyping of Pseudomonas aeruginosa Isolates

et al. 2016

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Accurate typing methods are required for efficient infection control. The emergence of whole-genome sequencing (WGS) technologies has enabled the development of genome-based methods applicable for routine typing and surveillance of bacterial pathogens. In this study, we developed the Pseudomonas aeruginosa serotyper (PAst) program, which enabled in silico serotyping of P. aeruginosa isolates using WGS data. PAst has been made publically available as a web service and aptly facilitates highthroughput serotyping analysis. The program overcomes critical issues such as the loss of in vitro typeability often associated with P. aeruginosa isolates from chronic infections and quickly determines the serogroup of an isolate based on the sequence of the O-specific antigen (OSA) gene cluster. Here, PAst analysis of 1,649 genomes resulted in successful serogroup assignments in 99.27% of the cases. This frequency is rarely achievable by conventional serotyping methods. The limited number of nontypeable isolates found using PAst was the result of either a complete absence of OSA genes in the genomes or the artifact of genomic misassembly. With PAst, P. aeruginosa serotype data can be obtained from WGS information alone. PAst is a highly efficient alternative to conventional serotyping methods in relation to outbreak surveillance of serotype O12 and other high-risk clones, while maintaining backward compatibility to historical serotype data. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a major cause of mortality and morbidity among hospitalized and compromised patients, including those with cystic fibrosis (CF). P. aeruginosa is well known for its ability to cause chronic and extensively drug-resistant infections (1). The outer membrane lipopolysaccharide (LPS) layer is a major virulence factor of P. aeruginosa (2). LPS has been linked to antibiotic resistance and immune evasion. Furthermore, LPS is one of the receptors that determines the susceptibility of the bacterium to bacteriophages and pyocins (2-4). Our ability to control P. aeruginosa infections depends on the availability of accurate typing methods. Previously, serotyping was a benchmark typing method for P. aeruginosa. In the 1980s, the International Antigenic Typing Scheme (IATS) was established to classify the species P. aeruginosa into 20 serotypes (O1 to O20) (5-7). Today, serotyping is infrequently used in the clinic for typing purposes, mainly because of the time-consuming protocol, the need for a continuous supply of serotype-specific antisera, and a high prevalence of polyagglutinating or nontypeable isolates.The loss of P. aeruginosa typeability has been known for decades and has often been linked to bacteria isolated from chronic infections, where typeability is lost over time during the course of infection (8, 9). A study performed by Pirnay et al. (10) showed that 65% of all P. aeruginosa isolates examined were either non-or multitypeable and therefore assigning a particular serotype to these strains would be difficult. The occur...

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On the Antibacterial Activity of Azacarboxylate Ligands: Lowered Metal Ion Affinities for Bis‐amide Derivatives of EDTA do not mean Reduced Activity

Mulla

Beecroft

Pál

et al. 2018

Chemistry A European J

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EDTA is widely used as an inhibitor of bacterial growth, affecting the uptake and control of metal ions by microorganisms. We describe the synthesis and characterisation of two symmetrical bis-amide derivatives of EDTA, featuring glycyl or pyridyl substituents: AmGly and AmPy . Metal ion affinities (logK) have been evaluated for a range of metals (Mg , Ca , Fe , Mn , Zn ), revealing less avid binding compared to EDTA. The solid-state structures of AmGly and of its Mg complex have been determined crystallographically. The latter shows an unusual 7-coordinate, capped octahedral Mg centre. The antibacterial activities of the two ligands and of EDTA have been evaluated against a range of health-relevant bacterial species, three Gram negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) and a Gram positive (Staphylococcus aureus). The AmPy ligand is the only one that displays a significant inhibitory effect against K. pneumoniae, but is less effective against the other organisms. AmGly exhibits a more powerful inhibitory effect against E. coli at lower concentrations than EDTA (<3 mm) or AmPy , but loses its efficacy at higher concentrations. The growth inhibition of EDTA and AmGly on mutant E. coli strains with defects in outer-membrane lipopolysaccharide (LPS) structures has been assessed to provide insight into the unexpected behaviour. Taken together, the results contradict the assumption of a simple link between metal ion affinity and antimicrobial efficacy.

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Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

Cited by 226 publications

References 172 publications

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

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

Application of Whole-Genome Sequencing Data for O-Specific Antigen Analysis and In Silico Serotyping of Pseudomonas aeruginosa Isolates

On the Antibacterial Activity of Azacarboxylate Ligands: Lowered Metal Ion Affinities for Bis‐amide Derivatives of EDTA do not mean Reduced Activity

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