scholarly journals Flagellum Density Regulates Proteus mirabilis Swarmer Cell Motility in Viscous Environments

2012 ◽  
Vol 195 (2) ◽  
pp. 368-377 ◽  
Author(s):  
Hannah H. Tuson ◽  
Matthew F. Copeland ◽  
Sonia Carey ◽  
Ryan Sacotte ◽  
Douglas B. Weibel
Keyword(s):  
Cell Motility ◽  
Proteus Mirabilis ◽  
Surface Density ◽  
Environmental Changes ◽  
Cell Length ◽  
Vegetative Cells ◽  
Swarmer Cell ◽  
Indwelling Catheters ◽  
Content Type ◽  
Tract Infections

ABSTRACTProteus mirabilisis an opportunistic pathogen that is frequently associated with urinary tract infections. In the lab,P. mirabiliscells become long and multinucleate and increase their number of flagella as they colonize agar surfaces during swarming. Swarming has been implicated in pathogenesis; however, it is unclear how energetically costly changes inP. mirabiliscell morphology translate into an advantage for adapting to environmental changes. We investigated two morphological changes that occur during swarming—increases in cell length and flagellum density—and discovered that an increase in the surface density of flagella enabled cells to translate rapidly through fluids of increasing viscosity; in contrast, cell length had a small effect on motility. We found that swarm cells had a surface density of flagella that was ∼5 times larger than that of vegetative cells and were motile in fluids with a viscosity that inhibits vegetative cell motility. To test the relationship between flagellum density and velocity, we overexpressed FlhD4C2, the master regulator of the flagellar operon, in vegetative cells ofP. mirabilisand found that increased flagellum density produced an increase in cell velocity. Our results establish a relationship betweenP. mirabilisflagellum density and cell motility in viscous environments that may be relevant to its adaptation during the infection of mammalian urinary tracts and movement in contact with indwelling catheters.

scholarly journals Bacterial Swarming Reduces Proteus mirabilis and Vibrio parahaemolyticus Cell Stiffness and Increases β-Lactam Susceptibility

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
George K. Auer ◽  
Piercen M. Oliver ◽  
Manohary Rajendram ◽  
Ti-Yu Lin ◽  
Qing Yao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Osmotic Pressure ◽  
Proteus Mirabilis ◽  
Vibrio Parahaemolyticus ◽  
Cell Stiffness ◽  
Bending Rigidity ◽  
Vegetative Cells ◽  
Swarmer Cell ◽  
Content Type ◽  
Peptidoglycan Layer

ABSTRACT Swarmer cells of the Gram-negative uropathogenic bacteria Proteus mirabilis and Vibrio parahaemolyticus become long (>10 to 100 μm) and multinucleate during their growth and motility on polymer surfaces. We demonstrated that the increasing cell length is accompanied by a large increase in flexibility. Using a microfluidic assay to measure single-cell mechanics, we identified large differences in the swarmer cell stiffness (bending rigidity) of P. mirabilis (5.5 × 10−22 N m2) and V. parahaemolyticus (1.0 × 10−22 N m2) compared to vegetative cells (1.4 × 10−20 N m2 and 2.2 × 10−22 N m2, respectively). The reduction in bending rigidity (∼2-fold to ∼26-fold) was accompanied by a decrease in the average polysaccharide strand length of the peptidoglycan layer of the cell wall from 28 to 30 disaccharides to 19 to 22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis peptidoglycan thickness from 1.5 nm (vegetative cells) to 1.0 nm (swarmer cells), and electron cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and susceptible to cell wall-modifying antibiotics (compared to vegetative cells)—they were ∼30% more likely to die after 3 h of treatment with MICs of the β-lactams cephalexin and penicillin G. The adaptive cost of “swarming” was offset by the increase in cell susceptibility to physical and chemical changes in their environment, thereby suggesting the development of new chemotherapies for bacteria that leverage swarming for the colonization of hosts and for survival. IMPORTANCE Proteus mirabilis and Vibrio parahaemolyticus are bacteria that infect humans. To adapt to environmental changes, these bacteria alter their cell morphology and move collectively to access new sources of nutrients in a process referred to as “swarming.” We found that changes in the composition and thickness of the peptidoglycan layer of the cell wall make swarmer cells of P. mirabilis and V. parahaemolyticus more flexible (i.e., reduce cell stiffness) and that they become more sensitive to osmotic pressure and cell wall-targeting antibiotics (e.g., β-lactams). These results highlight the importance of assessing the extracellular environment in determining antibiotic doses and the use of β-lactam antibiotics for treating infections caused by swarmer cells of P. mirabilis and V. parahaemolyticus.

scholarly journals New Aspects of RpoE in Uropathogenic Proteus mirabilis

2014 ◽  
Vol 83 (3) ◽  
pp. 966-977 ◽  
Author(s):  
Ming-Che Liu ◽  
Kuan-Ting Kuo ◽  
Hsiung-Fei Chien ◽  
Yi-Lin Tsai ◽  
Shwu-Jen Liaw
Keyword(s):  
Urinary Tract ◽  
Virulence Factors ◽  
Stress Responses ◽  
Proteus Mirabilis ◽  
Immune Cell ◽  
Polymyxin B ◽  
Urothelial Cells ◽  
Cationic Antimicrobial Peptide ◽  
Content Type ◽  
Tract Infections

Proteus mirabilisis a common human pathogen causing recurrent or persistent urinary tract infections (UTIs). The underlying mechanisms forP. mirabilisto establish UTIs are not fully elucidated. In this study, we showed that loss of the sigma factor E (RpoE), mediating extracytoplasmic stress responses, decreased fimbria expression, survival in macrophages, cell invasion, and colonization in mice but increased the interleukin-8 (IL-8) expression of urothelial cells and swarming motility. This is the first study to demonstrate that RpoE modulated expression of MR/P fimbriae by regulatingmrpI, a gene encoding a recombinase controlling the orientation of MR/P fimbria promoter. By real-time reverse transcription-PCR, we found that the IL-8 mRNA amount of urothelial cells was induced significantly by lipopolysaccharides extracted fromrpoEmutant but not from the wild type. These RpoE-associated virulence factors should be coordinately expressed to enhance the fitness ofP. mirabilisin the host, including the avoidance of immune attacks. Accordingly,rpoEmutant-infected mice displayed more immune cell infiltration in bladders and kidneys during early stages of infection, and therpoEmutant had a dramatically impaired ability of colonization. Moreover, it is noteworthy that urea (the major component in urine) and polymyxin B (a cationic antimicrobial peptide) can induce expression ofrpoEby the reporter assay, suggesting that RpoE might be activated in the urinary tract. Altogether, our results indicate that RpoE is important in sensing environmental cues of the urinary tract and subsequently triggering the expression of virulence factors, which are associated with the fitness ofP. mirabilis, to build up a UTI.

scholarly journals Tamm-Horsfall Protein Protects the Urinary Tract againstCandida albicans

2018 ◽  
Vol 86 (12) ◽  
Author(s):  
Alison Coady ◽  
Anissa R. Ramos ◽  
Joshua Olson ◽  
Victor Nizet ◽  
Kathryn A. Patras
Keyword(s):  
Urinary Tract ◽  
Fungal Pathogens ◽  
Treatment Strategies ◽  
Immune Defense ◽  
Renal Physiology ◽  
Bladder Epithelium ◽  
Indwelling Catheters ◽  
Content Type ◽  
Tract Infections

ABSTRACTUrinary tract infections (UTIs) caused by the human fungal pathogenCandida albicansand related species are prevalent in hospitalized patients, especially those on antibiotic therapy, with indwelling catheters, or with predisposing conditions such as diabetes or immunodeficiency. Understanding of key host defenses againstCandidaUTI is critical for developing effective treatment strategies. Tamm-Horsfall glycoprotein (THP) is the most abundant urine protein, with multiple roles in renal physiology and bladder protection. THP protects against bacterial UTI by blocking bacterial adherence to the bladder epithelium, but its role in defense against fungal pathogens is not yet described. Here we demonstrate that THP restricts colonization of the urinary tract byC. albicans. THP binds toC. albicanshyphae, but not the yeast form, in a manner dependent on fungal expression of the Als3 adhesion glycoprotein. THP directly blocksC. albicansadherence to bladder epithelial cellsin vitro, and THP-deficient mice display increased fungal burden in aC. albicansUTI model. This work outlines a previously unknown role for THP as an essential component for host immune defense against fungal urinary tract infection.

scholarly journals Transcriptome of Proteus mirabilis in the Murine Urinary Tract: Virulence and Nitrogen Assimilation Gene Expression

2011 ◽  
Vol 79 (7) ◽  
pp. 2619-2631 ◽  
Author(s):  
Melanie M. Pearson ◽  
Alejandra Yep ◽  
Sara N. Smith ◽  
Harry L. T. Mobley
Keyword(s):  
Gene Expression ◽  
Urinary Tract ◽  
Glutamate Dehydrogenase ◽  
Proteus Mirabilis ◽  
Transcriptional Analysis ◽  
Broth Culture ◽  
Pathogenic Potential ◽  
Content Type ◽  
Tract Infections

ABSTRACTThe enteric bacteriumProteus mirabilisis a common cause of complicated urinary tract infections. In this study, microarrays were used to analyzeP. mirabilisgene expressionin vivofrom experimentally infected mice. Urine was collected at 1, 3, and 7 days postinfection, and RNA was isolated from bacteria in the urine for transcriptional analysis. Across nine microarrays, 471 genes were upregulated and 82 were downregulatedin vivocompared toin vitrobroth culture. Genes upregulatedin vivoencoded mannose-resistantProteus-like (MR/P) fimbriae, urease, iron uptake systems, amino acid and peptide transporters, pyruvate metabolism enzymes, and a portion of the tricarboxylic acid (TCA) cycle enzymes. Flagella were downregulated. Ammonia assimilation geneglnA(glutamine synthetase) was repressedin vivo, whilegdhA(glutamate dehydrogenase) was upregulatedin vivo. Contrary to our expectations, ammonia availability due to urease activity inP. mirabilisdid not drive this gene expression. AgdhAmutant was growth deficient in minimal medium with citrate as the sole carbon source, and loss ofgdhAresulted in a significant fitness defect in the mouse model of urinary tract infection. UnlikeEscherichia coli, which repressesgdhAand upregulatesglnAin vivoand cannot utilize citrate, the data suggest thatP. mirabilisuses glutamate dehydrogenase to monitor carbon-nitrogen balance, and this ability contributes to the pathogenic potential ofP. mirabilisin the urinary tract.

scholarly journals Identification of virulence determinants in uropathogenic Proteus mirabilis using signature-tagged mutagenesis

2008 ◽  
Vol 57 (9) ◽  
pp. 1068-1078 ◽  
Author(s):  
Stephanie D. Himpsl ◽  
C. Virginia Lockatell ◽  
J. Richard Hebel ◽  
David E. Johnson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Mouse Model ◽  
Proteus Mirabilis ◽  
Virulence Determinants ◽  
Indwelling Catheters ◽  
Cba Mice ◽  
Transposon Mutants ◽  
Tract Infections

The Gram-negative bacterium Proteus mirabilis causes urinary tract infections (UTIs) in individuals with long-term indwelling catheters or those with functional or structural abnormalities of the urinary tract. Known virulence factors include urease, haemolysin, fimbriae, flagella, DsbA, a phosphate transporter and genes involved in cell-wall synthesis and metabolism, many of which have been identified using the technique of signature-tagged mutagenesis (STM). To identify additional virulence determinants and to increase the theoretical coverage of the genome, this study generated and assessed 1880 P. mirabilis strain HI4320 mutants using this method. Mutants with disruptions in genes vital for colonization of the CBA mouse model of ascending UTI were identified after performing primary and secondary in vivo screens in approximately 315 CBA mice, primary and secondary in vitro screens in both Luria broth and minimal A medium to eliminate mutants with minor growth deficiencies, and co-challenge competition experiments in approximately 500 CBA mice. After completion of in vivo screening, a total of 217 transposon mutants were attenuated in the CBA mouse model of ascending UTI. Following in vitro screening, this number was reduced to 196 transposon mutants with a probable role in virulence. Co-challenge competition experiments confirmed significant attenuation for 37 of the 93 transposon mutants tested, being outcompeted by wild-type HI4320. Following sequence analysis of the 37 mutants, transposon insertions were identified in genes including the peptidyl-prolyl isomerases surA and ppiA, glycosyltransferase cpsF, biopolymer transport protein exbD, transcriptional regulator nhaR, one putative fimbrial protein, flagellar M-ring protein fliF and hook protein flgE, and multiple metabolic genes.

scholarly journals Microevolution infimHGene of Mucosa-Associated Escherichia coli Strains Isolated from Pediatric Patients with Inflammatory Bowel Disease

2012 ◽  
Vol 80 (4) ◽  
pp. 1408-1417 ◽  
Author(s):  
Valerio Iebba ◽  
Maria Pia Conte ◽  
Maria Stefania Lepanto ◽  
Giovanni Di Nardo ◽  
Floriana Santangelo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Pediatric Patients ◽  
Environmental Changes ◽  
Mucosal Inflammation ◽  
Content Type ◽  
E Coli ◽  
Inflammatory Bowel ◽  
Tract Infections

ABSTRACTSeveral studies reported increased numbers of mucosa-associatedEscherichia colistrains in patients with inflammatory bowel disease (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC). The majority ofE. colistrains possess type 1 fimbriae, whose tip fibrillum protein, FimH, naturally undergoes amino acid replacements, an important process in the adaptation of commensalE. colistrains to environmental changes, like those observed in IBD and urinary tract infections. In this study, we analyzed mutational patterns in thefimHgene of 52 mucosa-associatedE. colistrains isolated from IBD and non-IBD pediatric patients, in order to investigate microevolution of this genetic trait. FimH-positive strains were also phylogenetically typed and tested for their adhesive ability on Caco-2 cells. Specific FimH alleles for each grouping feature were found. Mutations G66S and V27A were related to CD, while mutations A242V, V163A, and T74I were attributed to UC. Otherwise, the G66S, N70S, and S78N mutations were specifically attributed to B2/D phylogroups. The N70S and A119V mutations were related to adhesiveE. colistrains. Phylogroup B2, adhesive, and IBDE. colistrains showed a higher site substitution rate (SSR) in thefimHgene, together with a higher number of mutations. The degree of naïve mucosal inflammation was related to specific FimH alleles. Moreover, we could suggest that the V27A mutation is pathoadaptive for the CD intestinal habitat, while we could also suggest that both the N70S and S78N mutations are related to the more virulentE. coliB2 phylogroup. In conclusion, we found some FimH variants that seem to be more involved than others in the evolution of IBD pathogenesis.

scholarly journals Complete Genome Sequence of Proteus mirabilis Phage Myduc

2019 ◽  
Vol 8 (47) ◽  
Author(s):  
Jennifer Tran ◽  
Lauren Lessor ◽  
Chandler O’Leary ◽  
Jason Gill ◽  
Mei Liu
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Genome Sequence ◽  
Proteus Mirabilis ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
Small Genome ◽  
Tract Infections

Proteus mirabilis as a nosocomial pathogen is often the cause of urinary tract infections. This announcement describes the complete genome sequence of a P. mirabilis myophage named Myduc. Phage Myduc is related to Enterobacteria phage phiEcoM-GJ1, which belongs to a group of myophages with small genome sizes (52,000 to 56,000 bp) possessing a T7-like RNA polymerase.

scholarly journals Distinct Residues Contribute to Motility Repression and Autoregulation in the Proteus mirabilis Fimbria-Associated Transcriptional Regulator AtfJ

2016 ◽  
Vol 198 (15) ◽  
pp. 2100-2112 ◽  
Author(s):  
Nadine J. Bode ◽  
Kun-Wei Chan ◽  
Xiang-Peng Kong ◽  
Melanie M. Pearson
Keyword(s):  
Proteus Mirabilis ◽  
Structural Model ◽  
Mutational Analysis ◽  
Transcriptional Start Site ◽  
Three Dimensional ◽  
Transcriptional Regulator ◽  
Content Type ◽  
Terminal Domain ◽  
Wide Range ◽  
Tract Infections

ABSTRACTProteus mirabiliscontributes to a significant number of catheter-associated urinary tract infections, where coordinated regulation of adherence and motility is critical for ascending disease progression. Previously, the mannose-resistantProteus-like (MR/P) fimbria-associated transcriptional regulator MrpJ has been shown to both repress motility and directly induce the transcription of its own operon; in addition, it affects the expression of a wide range of cellular processes. Interestingly, 14 additionalmrpJparalogs are included in theP. mirabilisgenome. Looking at a selection of MrpJ paralogs, we discovered that these proteins, which consistently repress motility, also have nonidentical functions that include cross-regulation of fimbrial operons. A subset of paralogs, including AtfJ (encoded by the ambient temperature fimbrial operon), Fim8J, and MrpJ, are capable of autoinduction. We identified an element of theatfpromoter extending from 487 to 655 nucleotides upstream of the transcriptional start site that is responsive to AtfJ, and we found that AtfJ directly binds this fragment. Mutational analysis of AtfJ revealed that its two identified functions, autoregulation and motility repression, are not invariably linked. Residues within the DNA-binding helix-turn-helix domain are required for motility repression but not necessarily autoregulation. Likewise, the C-terminal domain is dispensable for motility repression but is essential for autoregulation. Supported by a three-dimensional (3D) structural model, we hypothesize that the C-terminal domain confers unique regulatory capacities on the AtfJ family of regulators.IMPORTANCEBalancing adherence with motility is essential for uropathogens to successfully establish a foothold in their host.Proteus mirabilisuses a fimbria-associated transcriptional regulator to switch between these antagonistic processes by increasing fimbrial adherence while simultaneously downregulating flagella. The discovery of multiple related proteins, many of which also function as motility repressors, encoded in theP. mirabilisgenome has raised considerable interest as to their functionality and potential redundancy in this organism. This study provides an important advance in this field by elucidating the nonidentical effects of these paralogs on a molecular level. Our mechanistic studies of one member of this group, AtfJ, shed light on how these differing functions may be conferred despite the limited sequence variety exhibited by the paralogous proteins.

scholarly journals Complete Genome Sequence of Proteus mirabilis Siphophage Saba

2019 ◽  
Vol 8 (41) ◽  
Author(s):  
James Nguyen ◽  
Laith Harb ◽  
Russell Moreland ◽  
Mei Liu ◽  
Jason J. Gill ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Proteus Mirabilis ◽  
Genome Annotation ◽  
Complete Genome ◽  
Enteric Bacterium ◽  
Gram Negative ◽  
Content Type ◽  
Protein Levels ◽  
Tract Infections

Proteus mirabilis is a Gram-negative enteric bacterium associated with complicated human urinary tract infections. Here, we present the complete genome annotation for P. mirabilis siphophage Saba. With a 60,056-bp genome and 75 predicted genes, Saba is most similar at the nucleotide and protein levels to phage Chi and Chi-like viruses.

scholarly journals Regulation of the Min Cell Division Inhibition Complex by the Rcs Phosphorelay in Proteus mirabilis

2015 ◽  
Vol 197 (15) ◽  
pp. 2499-2507 ◽  
Author(s):  
Kristen E. Howery ◽  
Katy M. Clemmer ◽  
Emrah Şimşek ◽  
Minsu Kim ◽  
Philip N. Rather
Keyword(s):  
Cell Division ◽  
Cell Differentiation ◽  
Proteus Mirabilis ◽  
Cell Elongation ◽  
Response Regulator ◽  
Swarmer Cell ◽  
Content Type ◽  
Expression Of Genes ◽  
Rapid Amplification

ABSTRACTA key regulator of swarming inProteus mirabilisis the Rcs phosphorelay, which repressesflhDC, encoding the master flagellar regulator FlhD4C2. Mutants inrcsB, the response regulator in the Rcs phosphorelay, hyperswarm on solid agar and differentiate into swarmer cells in liquid, demonstrating that this system also influences the expression of genes central to differentiation. To gain a further understanding of RcsB-regulated genes involved in swarmer cell differentiation, transcriptome sequencing (RNA-Seq) was used to examine the RcsB regulon. Among the 133 genes identified,minCandminD, encoding cell division inhibitors, were identified as RcsB-activated genes. A third gene,minE, was shown to be part of an operon withminCD. To examineminCDEregulation, theminpromoter was identified by 5′ rapid amplification of cDNA ends (5′-RACE), and both transcriptionallacZfusions and quantitative real-time reverse transcriptase (qRT) PCR were used to confirm that theminCDEoperon was RcsB activated. Purified RcsB was capable of directly binding theminCpromoter region. To determine the role of RcsB-mediated activation ofminCDEin swarmer cell differentiation, a polarminCmutation was constructed. This mutant formed minicells during growth in liquid, produced shortened swarmer cells during differentiation, and exhibited decreased swarming motility.IMPORTANCEThis work describes the regulation and role of the MinCDE cell division system inP. mirabilisswarming and swarmer cell elongation. Prior to this study, the mechanisms that inhibit cell division and allow swarmer cell elongation were unknown. In addition, this work outlines for the first time the RcsB regulon inP. mirabilis. Taken together, the data presented in this study begin to address howP. mirabiliselongates upon contact with a solid surface.

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