Genomes comparison of two Proteus mirabilis clones showing varied swarming ability.

BACKGROUND: Proteus mirabilis is a Gram-negative bacteria most noted for its involvement with catheter-associated urinary tract infections. It is also known for its multicellular migration over solid surfaces, referred to as 'swarming motility'. Here we analyzed the genomic sequences of two P. mirabilis isolates, designated K38 and K39, which exhibit varied swarming ability. METHODS AND RESULTS: The isolates genomes were sequenced using Illumina NextSeq sequencer, resulting in about 3.94 Mbp, with a GC content of 38.6%, genomes. Genomes were subjected for in silico comparative investigation. We revealed that, despite a difference in swarming motility, the isolates showed high genomic relatedness (up to 100% ANI similarity), suggesting that one of the isolates probably originated from the other. CONCLUSIONS: The genomic sequences will allow us to investigate the mechanism driving this intriguing phenotypic heterogeneity between closely related P. mirabilis isolates. Phenotypic heterogeneity is an adaptive strategy of bacterial cells to several environmental pressures. It is also an important factor related to their pathogenesis. Therefore, the availability of these genomic sequences will facilitate studies that focus on the host-pathogen interactions during catheter-associated urinary tract infections.

Loop-Mediated Isothermal Amplification of DNA (LAMP) as an Alternative Method for Determining Bacteria in Wound Infections.

The increasing number of patients with chronic wounds requires the development of quick and accurate diagnostics methods. One of the key and challenging aspects of treating ulcers is to control wound infection. Early detection of infection is essential for the application of suitable treatment methods, such as systemic antibiotics or other antimicrobial agents. Clinically, the most frequently used method for detecting microorganisms in wounds is through a swab and culture on appropriate media. This test has major limitations, such as the long bacterial growth time and the selectivity of bacterial growth. This article presents an overview of molecular methods for detecting bacteria in wounds, including real-time polymerase chain reaction (rtPCR), quantitative polymerase chain reaction (qPCR), genotyping, next-generation sequencing (NGS), and loop-mediated isothermal amplification (LAMP). We focus on the LAMP method, which has not yet been widely used to detect bacteria in wounds, but it is an interesting alternative to conventional detection methods. LAMP does not require additional complicated equipment and provides the fastest detection time for microorganisms (approx. 30 min reaction). It also allows the use of many pairs of primers in one reaction and determination of up to 15 organisms in one sample. Isothermal amplification of DNA is currently the easiest and most economical method for microbial detection in wound infection. Direct visualization of the reaction with dyes, along with omitting DNA isolation, has increased the potential use of this method.

A benzimidazole-based ruthenium(IV) complex inhibits Pseudomonas aeruginosa biofilm formation by interacting with siderophores and the cell envelope, and inducing oxidative stress.

Pseudomonas aeruginosa biofilm-associated infections are a serious medical problem, and new compounds and therapies acting through novel mechanisms are much needed. Herein, the authors report a ruthenium(IV) complex that reduces P. aeruginosa PAO1 biofilm formation by 84%, and alters biofilm morphology and the living-to-dead cell ratio at 1 mM concentration. Including the compound in the culture medium altered the pigments secreted by PAO1, and fluorescence spectra revealed a decrease in pyoverdine. Scanning electron microscopy showed that the ruthenium complex did not penetrate the bacterial cell wall, but accumulated on external cell structures. Fluorescence quenching experiments indicated strong binding of the ruthenium complex to both plasmid DNA and bovine serum albumin. Formamidopyrimidine DNA N-glycosylase (Fpg) protein digestion of plasmid DNA isolated after ruthenium(IV) complex treatment revealed the generation of oxidative stress, which was further proved by the observed upregulation of catalase and superoxide dismutase gene expression.

Draft Genome Sequences of Proteus mirabilis K1609 and K670: A Model Strains for Territoriality Examination.

Proteus mirabilis is a pathogenic Gram-negative bacterium characterized by its ability to swarm across surfaces, which frequently leads to colonization of the urinary tract and causes severe infections. P. mirabilis strains are also well known from their self-recognition phenomenon, referred to as Dienes phenomenon. In this study, we present novel aspect of self-recognition, which is a hierarchy in terms of strains territoriality. We report the draft genome sequences of P. mirabilis K1609 and K670 strains exhibiting the strongest and the weakest territoriality, respectively. Our results indicated that K1609 is closely related to strain BB2000, a model system for self-recognition, comparing with the K670. We annotated genes associated with recognition of kin and swarming initiation control and indicated polymorphisms by which observed differences in territoriality might results from. The phenotypic and genomic features of both strains reveal their application as a model organisms for studying not only the mechanisms of kin-recognition but also strains territoriality, thus providing new approach to the phenomenon. Availability of these genome sequences may facilitate understanding of the interactions between P. mirabilis strains.

The role of Proteus mirabilis cell wall features in biofilm formation.

Biofilms formed by Proteus mirabilis strains are a serious medical problem, especially in the case of urinary tract infections. Early stages of biofilm formation, such as reversible and irreversible adhesion, are essential for bacteria to form biofilm and avoid eradication by antibiotic therapy. Adhesion to solid surfaces is a complex process where numerous factors play a role, where hydrophobic and electrostatic interactions with solid surface seem to be substantial. Cell surface hydrophobicity and electrokinetic potential of bacterial cells depend on their surface composition and structure, where lipopolysaccharide, in Gram-negative bacteria, is prevailing. Our studies focused on clinical and laboratory P. mirabilis strains, where laboratory strains have determined LPS structures. Adherence and biofilm formation tests revealed significant differences between strains adhered in early stages of biofilm formation. Amounts of formed biofilm were expressed by the absorption of crystal violet. Higher biofilm amounts were formed by the strains with more negative values of zeta potential. In contrast, high cell surface hydrophobicity correlated with low biofilm amount.

Into the understanding the multicellular lifestyle of Proteus mirabilis on solid surfaces.

Indwelling urinary catheterization can lead to the development of catheter-associated urinary tract infections (CAUTIs), an important type of nosocomial infection, as well as other medical issues among institutionalized adults. Recently, Proteus mirabilis was highlighted as the important cause of CAUTIs. The pathogenicity of P. mirabilis is dependent on two multicellular types of surface colonization: the adherence and swarming motility. Adhesion, mostly mediated by fimbrial and nonfimbrial adhesins, is important for the initiation of biofilm formation. Moreover, the production of urease frequently results in biofilm crystallization, which leads to the blockage of catheters. The heterologous polymeric matrix of the biofilm offers protection against antibiotics and the host immune system. P. mirabilis displays remarkable motility abilities. After contact with solid surfaces, hyper-flagellated cells are able to rapidly migrate. The importance of swarming motility in CAUTIs development remains controversial; however, it was indicated that swarming cells were able to co-express other virulence factors. Furthermore, flagella are strong immunomodulating proteins. On the other hand, both biofilm formation and swarming motility implicates multiple inter- and intraspecies interactions, which might contribute to the pathogenicity.

Draft Genome of Proteus mirabilis Serogroup O18 Elaborating Phosphocholine-Decorated O Antigen.

Proteus mirabilis is a pathogenic, Gram-negative, rod-shaped bacterium that causes ascending urinary tract infections. Swarming motility, urease production, biofilm formation, and the properties of its lipopolysaccharide (LPS) are all factors that contribute to the virulence of this bacterium. Uniquely, members of the O18 serogroup elaborate LPS molecules capped with O antigen polymers built of pentasaccharide repeats; these repeats are modified with a phosphocholine (ChoP) moiety attached to the proximal sugar of each O unit. Decoration of the LPS with ChoP is an important surface modification of many pathogenic and commensal bacteria. The presence of ChoP on the bacterial envelope is correlated with pathogenicity, as decoration with ChoP plays a role in bacterial adhesion to mucosal surfaces, resistance to antimicrobial peptides and sensitivity to complement-mediated killing in several species. The genome of P. mirabilis O18 is 3.98 Mb in size, containing 3,762 protein-coding sequences and an overall GC content of 38.7%. Annotation performed using the RAST Annotation Server revealed genes associated with choline phosphorylation, uptake and transfer. Moreover, amino acid sequence alignment of the translated licC gene revealed it to be homologous to LicC from Streptococcus pneumoniae encoding CTP:phosphocholine cytidylyltransferase. Recognized homologs are located in the O antigen gene clusters of Proteus species, near the wzx gene encoding the O antigen flippase, which translocates lipid-linked O units across the inner membrane. This study reveals the genes potentially engaged in LPS decoration with ChoP in P. mirabilis O18.