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Harry L. T. Mobley - One of the best experts on this subject based on the ideXlab platform.
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proteus Mirabilis overview
Methods of Molecular Biology, 2019Co-Authors: Harry L. T. MobleyAbstract:Proteus Mirabilis, a Gram-negative bacterium, commonly causes catheter-associated urinary tract infections, wound infections, gastroenteritis and, in some cases, bacteremia. The phenotypic hallmarks of this bacterium include swarming motility, urease and hemolysin production, and synthesis of numerous adherence fimbriae. While routine bacteriological methodology may often be used to study this pathogen, frequently one requires specialized techniques to investigate the pathogenesis of this species. Here, a brief overview of the discoveries associated with this fascinating bacterium illuminates the need for the development of specialized techniques to further probe the biology of P. Mirabilis.
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vaccination to protect against proteus Mirabilis challenge utilizing the ascending model of urinary tract infection
Methods of Molecular Biology, 2019Co-Authors: Sara N Smith, Stephanie D Himpsl, Harry L. T. MobleyAbstract:Proteus Mirabilis is a major cause of complicated urinary tract infections (UTIs). P. Mirabilis' urease activity hydrolyzes urea and raises urine pH levels, which can catalyze bladder and kidney stone formation. This urolithiasis leads to harder-to-treat infections, possible urinary blockage, and subsequent septicemia. Development of a mucosal vaccine against P. Mirabilis urinary tract infections is critical to protect against this potentially deadly infection process. Here, we describe the methodology necessary to produce a vaccine candidate conjugated to cholera toxin, administer the vaccine via the intranasal route, and test efficacy in a murine transurethral P. Mirabilis infection model.
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mrpj directly regulates proteus Mirabilis virulence factors including fimbriae and type vi secretion during urinary tract infection
Infection and Immunity, 2018Co-Authors: Irina Debnath, Harry L. T. Mobley, Melanie M Pearso, Sara N Smith, Anne M Stringe, Joseph T WadeAbstract:ABSTRACT Proteus Mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs) and urolithiasis. The transcriptional regulator MrpJ inversely modulates two critical aspects of P. Mirabilis UTI progression: fimbria-mediated attachment and flagellum-mediated motility. Transcriptome data indicated a network of virulence-associated genes under MrpJ9s control. Here, we identify the direct gene regulon of MrpJ and its contribution to P. Mirabilis pathogenesis, leading to the discovery of novel virulence targets. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) was used for the first time in a CAUTI pathogen to probe for in vivo direct targets of MrpJ. Selected MrpJ-regulated genes were mutated and assessed for their contribution to UTI using a mouse model. ChIP-seq revealed a palindromic MrpJ binding sequence and 78 MrpJ-bound regions, including binding sites upstream of genes involved in motility, fimbriae, and a type VI secretion system (T6SS). A combinatorial mutation approach established the contribution of three fimbriae (fim8A, fim14A, and pmpA) to UTI and a new pathogenic role for the T6SS in UTI progression. In conclusion, this study (i) establishes the direct gene regulon and an MrpJ consensus binding site and (ii) led to the discovery of new virulence genes in P. Mirabilis UTI, which could be targeted for therapeutic intervention of CAUTI.
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genome wide transposon mutagenesis of proteus Mirabilis essential genes fitness factors for catheter associated urinary tract infection and the impact of polymicrobial infection on fitness requirements
PLOS Pathogens, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Valerie Forsythdeornellas, Alexandra O Johnson, Lili Zhao, Weisheng Wu, Harry L. T. MobleyAbstract:The Gram-negative bacterium Proteus Mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs), which are often polymicrobial. Numerous prior studies have uncovered virulence factors for P. Mirabilis pathogenicity in a murine model of ascending UTI, but little is known concerning pathogenesis during CAUTI or polymicrobial infection. In this study, we utilized five pools of 10,000 transposon mutants each and transposon insertion-site sequencing (Tn-Seq) to identify the full arsenal of P. Mirabilis HI4320 fitness factors for single-species versus polymicrobial CAUTI with Providencia stuartii BE2467. 436 genes in the input pools lacked transposon insertions and were therefore concluded to be essential for P. Mirabilis growth in rich medium. 629 genes were identified as P. Mirabilis fitness factors during single-species CAUTI. Tn-Seq from coinfection with P. stuartii revealed 217/629 (35%) of the same genes as identified by single-species Tn-Seq, and 1353 additional factors that specifically contribute to colonization during coinfection. Mutants were constructed in eight genes of interest to validate the initial screen: 7/8 (88%) mutants exhibited the expected phenotypes for single-species CAUTI, and 3/3 (100%) validated the expected phenotypes for polymicrobial CAUTI. This approach provided validation of numerous previously described P. Mirabilis fitness determinants from an ascending model of UTI, the discovery of novel fitness determinants specifically for CAUTI, and a stringent assessment of how polymicrobial infection influences fitness requirements. For instance, we describe a requirement for branched-chain amino acid biosynthesis by P. Mirabilis during coinfection due to high-affinity import of leucine by P. stuartii. Further investigation of genes and pathways that provide a competitive advantage during both single-species and polymicrobial CAUTI will likely provide robust targets for therapeutic intervention to reduce P. Mirabilis CAUTI incidence and severity.
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the pathogenic potential of proteus Mirabilis is enhanced by other uropathogens during polymicrobial urinary tract infection
Infection and Immunity, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Alejandra Yep, Alexandra O Johnson, Weisheng Wu, Kathryn A Eaton, Valerie Deornellas, Lona Mody, Harry L. T. MobleyAbstract:ABSTRACT Urinary catheter use is prevalent in health care settings, and polymicrobial colonization by urease-positive organisms, such as Proteus Mirabilis and Providencia stuartii, commonly occurs with long-term catheterization. We previously demonstrated that coinfection with P. Mirabilis and P. stuartii increased overall urease activity in vitro and disease severity in a model of urinary tract infection (UTI). In this study, we expanded these findings to a murine model of catheter-associated UTI (CAUTI), delineated the contribution of enhanced urease activity to coinfection pathogenesis, and screened for enhanced urease activity with other common CAUTI pathogens. In the UTI model, mice coinfected with the two species exhibited higher urine pH values, urolithiasis, bacteremia, and more pronounced tissue damage and inflammation compared to the findings for mice infected with a single species, despite having a similar bacterial burden within the urinary tract. The presence of P. stuartii, regardless of urease production by this organism, was sufficient to enhance P. Mirabilis urease activity and increase disease severity, and enhanced urease activity was the predominant factor driving tissue damage and the dissemination of both organisms to the bloodstream during coinfection. These findings were largely recapitulated in the CAUTI model. Other uropathogens also enhanced P. Mirabilis urease activity in vitro , including recent clinical isolates of Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. We therefore conclude that the underlying mechanism of enhanced urease activity may represent a widespread target for limiting the detrimental consequences of polymicrobial catheter colonization, particularly by P. Mirabilis and other urease-positive bacteria.
Melanie M Pearson - One of the best experts on this subject based on the ideXlab platform.
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from catheter to kidney stone the uropathogenic lifestyle of proteus Mirabilis
Trends in Microbiology, 2017Co-Authors: Allison N Norsworthy, Melanie M PearsonAbstract:Proteus Mirabilis is a model organism for urease-producing uropathogens. These diverse bacteria cause infection stones in the urinary tract and form crystalline biofilms on indwelling urinary catheters, frequently leading to polymicrobial infection. Recent work has elucidated how P. Mirabilis causes all of these disease states. Particularly exciting is the discovery that this bacterium forms large clusters in the bladder lumen that are sites for stone formation. These clusters, and other steps of infection, require two virulence factors in particular: urease and MR/P fimbriae. Highlighting the importance of MR/P fimbriae is the cotranscribed regulator, MrpJ, which globally controls virulence. Overall, P. Mirabilis exhibits an extraordinary lifestyle, and further probing will answer exciting basic microbiological and clinically relevant questions.
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proteus Mirabilis fimbriae and urease dependent clusters assemble in an extracellular niche to initiate bladder stone formation
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Jessica N Schaffer, Allison N Norsworthy, Tungtien Sun, Melanie M PearsonAbstract:The catheter-associated uropathogen Proteus Mirabilis frequently causes urinary stones, but little has been known about the initial stages of bladder colonization and stone formation. We found that P. Mirabilis rapidly invades the bladder urothelium, but generally fails to establish an intracellular niche. Instead, it forms extracellular clusters in the bladder lumen, which form foci of mineral deposition consistent with development of urinary stones. These clusters elicit a robust neutrophil response, and we present evidence of neutrophil extracellular trap generation during experimental urinary tract infection. We identified two virulence factors required for cluster development: urease, which is required for urolithiasis, and mannose-resistant Proteus-like fimbriae. The extracellular cluster formation by P. Mirabilis stands in direct contrast to uropathogenic Escherichia coli, which readily formed intracellular bacterial communities but not luminal clusters or urinary stones. We propose that extracellular clusters are a key mechanism of P. Mirabilis survival and virulence in the bladder.
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proteus Mirabilis and urinary tract infections
Microbiology spectrum, 2015Co-Authors: Jessica N Schaffer, Melanie M PearsonAbstract:Proteus Mirabilis is a Gram-negative bacterium and is well known for its ability to robustly swarm across surfaces in a striking bulls’-eye pattern. Clinically, this organism is most frequently a pathogen of the urinary tract, particularly in patients undergoing long-term catheterization. This review covers P. Mirabilis with a focus on urinary tract infections (UTI), including disease models, vaccine development efforts, and clinical perspectives. Flagella-mediated motility, both swimming and swarming, is a central facet of this organism. The regulation of this complex process and its contribution to virulence is discussed, along with the type VI-secretion system-dependent intra-strain competition, which occurs during swarming. P. Mirabilis uses a diverse set of virulence factors to access and colonize the host urinary tract, including urease and stone formation, fimbriae and other adhesins, iron and zinc acquisition, proteases and toxins, biofilm formation, and regulation of pathogenesis. While significant advances in this field have been made, challenges remain to combatting complicated UTI and deciphering P. Mirabilis pathogenesis.
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transcriptome of proteus Mirabilis in the murine urinary tract virulence and nitrogen assimilation gene expression
Infection and Immunity, 2011Co-Authors: Melanie M Pearson, Sara N Smith, Alejandra Yep, Harry L. T. MobleyAbstract:The enteric bacterium Proteus Mirabilis is a common cause of complicated urinary tract infections. In this study, microarrays were used to analyze P. Mirabilis gene expression in vivo from 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 downregulated in vivo compared to in vitro broth culture. Genes upregulated in vivo encoded mannose-resistant Proteus-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 gene glnA (glutamine synthetase) was repressed in vivo, while gdhA (glutamate dehydrogenase) was upregulated in vivo. Contrary to our expectations, ammonia availability due to urease activity in P. Mirabilis did not drive this gene expression. A gdhA mutant was growth deficient in minimal medium with citrate as the sole carbon source, and loss of gdhA resulted in a significant fitness defect in the mouse model of urinary tract infection. Unlike Escherichia coli, which represses gdhA and upregulates glnA in vivo and cannot utilize citrate, the data suggest that P. Mirabilis uses glutamate dehydrogenase to monitor carbon-nitrogen balance, and this ability contributes to the pathogenic potential of P. Mirabilis in the urinary tract.
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transcriptome of swarming proteus Mirabilis
Infection and Immunity, 2010Co-Authors: Melanie M Pearson, Sara N Smith, David A Rasko, Harry L. T. MobleyAbstract:Proteus Mirabilis, a member of the Enterobacteriaceae and an opportunistic pathogen, is especially problematic as a urinary tract pathogen in catheterized patients, those with spinal cord injury, or those with anatomical abnormality of the urinary tract (reviewed in reference 16). This urease-positive bacterium causes an increase in urinary pH and the production of kidney and bladder stones (25, 39). In addition, urinary catheters become encrusted and even blocked during P. Mirabilis infections (45). As our population continues to age, resulting in larger numbers of catheterized patients in hospitals and nursing homes, this organism will likely be of special concern as an agent of nosocomial infections. Particularly worrisome is the more frequent appearance of multidrug-resistant strains of P. Mirabilis (17, 47). P. Mirabilis was first characterized in 1885 by G. Hauser for its ability to swarm over agar surfaces, resulting in a characteristic bull's-eye pattern (reviewed in reference 65). During the swarm process, P. Mirabilis differentiates into very long (>50 μm), multinucleate, highly motile hyperflagellated cells (65). At intervals, swarm cells slow down or cease movement and dedifferentiate into shorter rod-shaped cells in what is known as the consolidation phase. Repeated cycles of swarming and consolidation lead to the bull's-eye pattern. Reflecting this phenotype, P. Mirabilis was named for the Greek god Proteus, who was able to change form at will to avoid questioning (65). Flagellum-mediated swarming, accompanied by cell elongation, has been observed in other bacterial species, including Escherichia coli, Salmonella enterica serovar Typhimurium, Serratia marcescens, Vibrio parahaemolyticus, and Pseudomonas aeruginosa (reviewed in references 22, 28, and 61). However, it should be noted that swarming by these species requires a much lower agar concentration and lacks the characteristic cyclic pattern of swarming and consolidation. Thus, swarming by these other species is analogous but not identical to the robust swarming activity of P. Mirabilis. Numerous studies have been conducted in an effort to understand how and why P. Mirabilis swarms, yet despite some advances, much remains unknown. However, it has been definitively demonstrated that flagella (2, 8) and chemotaxis (12) are necessary for swarming. Polysaccharides (including lipopolysaccharides [LPS]) (10, 26), extracellular matrix components (57), and fatty acids (40) may also play roles in helping P. Mirabilis to move across solid surfaces. Putrescine (59) and glutamine (3) represent signals involved in the initiation of swarming. Cell density may also play a role in the transition between swarming and consolidation phases (53) and in the initiation of swarming (11); however, a luxS mutant of P. Mirabilis swarms normally (56). Mutagenesis and library screens have identified several regulators of swarming motility, including rsbA (11), ccmA (31), umoA, umoB, umoC, umoD (20), wosA (30), disA (58), and the Lon protease (14). Multiple virulence factors are also upregulated during swarming, including hemolysin, urease, and the Zap metalloprotease (4, 62). In the clinical setting, swarming may present an issue for patients with indwelling urinary catheters. P. Mirabilis swarms across the surface of both latex and silicone urinary catheters (35, 54), thus gaining access to the bladder. Rapid colonization of catheter surfaces, coupled with catheter encrustation resulting from urease production, makes P. Mirabilis a particularly troublesome pathogen in the hospital setting. The recent sequencing and annotation of the P. Mirabilis HI4320 genome (52) allowed for the construction of a P. Mirabilis microarray. In this report, the first use of microarrays to study P. Mirabilis gene expression, we investigated the transcriptome of this organism during its swarming and consolidation phases and contrasted gene expression during these phases with expression during logarithmic-phase broth culture. Both swarming and consolidation phases were monitored in real time. Only the edges of colonies in swarming or consolidation phases, confirmed by both Gram staining and microscopic observation of motility in intact colonies, were collected so that only the youngest cells of the colony were analyzed. Selected genes identified by microarray analysis were mutated and assessed for their effect on swarm behavior and virulence in a mouse model of ascending urinary tract infection. The necessity of active protein synthesis during swarming was also investigated.
Sara N Smith - One of the best experts on this subject based on the ideXlab platform.
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indwelling urinary catheter model of proteus Mirabilis infection
Methods of Molecular Biology, 2019Co-Authors: Sara N Smith, Chelsie E ArmbrusteAbstract:Uncomplicated urinary tract infections, especially those caused by Escherichia coli, have historically been widely studied. However, complicated urinary tract infections are presenting ever increasing healthcare challenges, particularly with Proteus Mirabilis. P. Mirabilis is often found on indwelling urinary catheters causing monomicrobial and polymicrobial catheter-associated urinary tract infection (CAUTI). Widespread antibiotic resistance, combined with the ability of P. Mirabilis to form urinary calculi during infection, warrants further investigation of this pathogen and its host interaction in an infection model that more closely mimics the presence of an indwelling urinary catheter. Here, we describe the methods necessary to establish a murine model of P. Mirabilis CAUTI.
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vaccination to protect against proteus Mirabilis challenge utilizing the ascending model of urinary tract infection
Methods of Molecular Biology, 2019Co-Authors: Sara N Smith, Stephanie D Himpsl, Harry L. T. MobleyAbstract:Proteus Mirabilis is a major cause of complicated urinary tract infections (UTIs). P. Mirabilis' urease activity hydrolyzes urea and raises urine pH levels, which can catalyze bladder and kidney stone formation. This urolithiasis leads to harder-to-treat infections, possible urinary blockage, and subsequent septicemia. Development of a mucosal vaccine against P. Mirabilis urinary tract infections is critical to protect against this potentially deadly infection process. Here, we describe the methodology necessary to produce a vaccine candidate conjugated to cholera toxin, administer the vaccine via the intranasal route, and test efficacy in a murine transurethral P. Mirabilis infection model.
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mrpj directly regulates proteus Mirabilis virulence factors including fimbriae and type vi secretion during urinary tract infection
Infection and Immunity, 2018Co-Authors: Irina Debnath, Harry L. T. Mobley, Melanie M Pearso, Sara N Smith, Anne M Stringe, Joseph T WadeAbstract:ABSTRACT Proteus Mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs) and urolithiasis. The transcriptional regulator MrpJ inversely modulates two critical aspects of P. Mirabilis UTI progression: fimbria-mediated attachment and flagellum-mediated motility. Transcriptome data indicated a network of virulence-associated genes under MrpJ9s control. Here, we identify the direct gene regulon of MrpJ and its contribution to P. Mirabilis pathogenesis, leading to the discovery of novel virulence targets. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) was used for the first time in a CAUTI pathogen to probe for in vivo direct targets of MrpJ. Selected MrpJ-regulated genes were mutated and assessed for their contribution to UTI using a mouse model. ChIP-seq revealed a palindromic MrpJ binding sequence and 78 MrpJ-bound regions, including binding sites upstream of genes involved in motility, fimbriae, and a type VI secretion system (T6SS). A combinatorial mutation approach established the contribution of three fimbriae (fim8A, fim14A, and pmpA) to UTI and a new pathogenic role for the T6SS in UTI progression. In conclusion, this study (i) establishes the direct gene regulon and an MrpJ consensus binding site and (ii) led to the discovery of new virulence genes in P. Mirabilis UTI, which could be targeted for therapeutic intervention of CAUTI.
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genome wide transposon mutagenesis of proteus Mirabilis essential genes fitness factors for catheter associated urinary tract infection and the impact of polymicrobial infection on fitness requirements
PLOS Pathogens, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Valerie Forsythdeornellas, Alexandra O Johnson, Lili Zhao, Weisheng Wu, Harry L. T. MobleyAbstract:The Gram-negative bacterium Proteus Mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs), which are often polymicrobial. Numerous prior studies have uncovered virulence factors for P. Mirabilis pathogenicity in a murine model of ascending UTI, but little is known concerning pathogenesis during CAUTI or polymicrobial infection. In this study, we utilized five pools of 10,000 transposon mutants each and transposon insertion-site sequencing (Tn-Seq) to identify the full arsenal of P. Mirabilis HI4320 fitness factors for single-species versus polymicrobial CAUTI with Providencia stuartii BE2467. 436 genes in the input pools lacked transposon insertions and were therefore concluded to be essential for P. Mirabilis growth in rich medium. 629 genes were identified as P. Mirabilis fitness factors during single-species CAUTI. Tn-Seq from coinfection with P. stuartii revealed 217/629 (35%) of the same genes as identified by single-species Tn-Seq, and 1353 additional factors that specifically contribute to colonization during coinfection. Mutants were constructed in eight genes of interest to validate the initial screen: 7/8 (88%) mutants exhibited the expected phenotypes for single-species CAUTI, and 3/3 (100%) validated the expected phenotypes for polymicrobial CAUTI. This approach provided validation of numerous previously described P. Mirabilis fitness determinants from an ascending model of UTI, the discovery of novel fitness determinants specifically for CAUTI, and a stringent assessment of how polymicrobial infection influences fitness requirements. For instance, we describe a requirement for branched-chain amino acid biosynthesis by P. Mirabilis during coinfection due to high-affinity import of leucine by P. stuartii. Further investigation of genes and pathways that provide a competitive advantage during both single-species and polymicrobial CAUTI will likely provide robust targets for therapeutic intervention to reduce P. Mirabilis CAUTI incidence and severity.
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the pathogenic potential of proteus Mirabilis is enhanced by other uropathogens during polymicrobial urinary tract infection
Infection and Immunity, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Alejandra Yep, Alexandra O Johnson, Weisheng Wu, Kathryn A Eaton, Valerie Deornellas, Lona Mody, Harry L. T. MobleyAbstract:ABSTRACT Urinary catheter use is prevalent in health care settings, and polymicrobial colonization by urease-positive organisms, such as Proteus Mirabilis and Providencia stuartii, commonly occurs with long-term catheterization. We previously demonstrated that coinfection with P. Mirabilis and P. stuartii increased overall urease activity in vitro and disease severity in a model of urinary tract infection (UTI). In this study, we expanded these findings to a murine model of catheter-associated UTI (CAUTI), delineated the contribution of enhanced urease activity to coinfection pathogenesis, and screened for enhanced urease activity with other common CAUTI pathogens. In the UTI model, mice coinfected with the two species exhibited higher urine pH values, urolithiasis, bacteremia, and more pronounced tissue damage and inflammation compared to the findings for mice infected with a single species, despite having a similar bacterial burden within the urinary tract. The presence of P. stuartii, regardless of urease production by this organism, was sufficient to enhance P. Mirabilis urease activity and increase disease severity, and enhanced urease activity was the predominant factor driving tissue damage and the dissemination of both organisms to the bloodstream during coinfection. These findings were largely recapitulated in the CAUTI model. Other uropathogens also enhanced P. Mirabilis urease activity in vitro , including recent clinical isolates of Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. We therefore conclude that the underlying mechanism of enhanced urease activity may represent a widespread target for limiting the detrimental consequences of polymicrobial catheter colonization, particularly by P. Mirabilis and other urease-positive bacteria.
Chelsie E Armbruster - One of the best experts on this subject based on the ideXlab platform.
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a rare opportunist morganella morganii decreases severity of polymicrobial catheter associated urinary tract infection
Infection and Immunity, 2019Co-Authors: Brian S. Learman, Aimee L. Brauer, Kathryn A Eaton, Chelsie E ArmbrusterAbstract:ABSTRACT Catheter-associated urinary tract infections (CAUTIs) are common hospital-acquired infections and frequently polymicrobial, which complicates effective treatment. However, few studies experimentally address the consequences of polymicrobial interactions within the urinary tract, and the clinical significance of polymicrobial bacteriuria is not fully understood. Proteus Mirabilis is one of the most common causes of monomicrobial and polymicrobial CAUTI and frequently cocolonizes with Enterococcus faecalis, Escherichia coli, Providencia stuartii, and Morganella morganii. P. Mirabilis infections are particularly challenging due to its potent urease enzyme, which facilitates formation of struvite crystals, catheter encrustation, blockage, and formation of urinary stones. We previously determined that interactions between P. Mirabilis and other uropathogens can enhance P. Mirabilis urease activity, resulting in greater disease severity during experimental polymicrobial infection. Our present work reveals that M. morganii acts on P. Mirabilis in a contact-independent manner to decrease urease activity. Furthermore, M. morganii actively prevents urease enhancement by E. faecalis, P. stuartii, and E. coli. Importantly, these interactions translate to modulation of disease severity during experimental CAUTI, predominantly through a urease-dependent mechanism. Thus, products secreted by multiple bacterial species in the milieu of the catheterized urinary tract can directly impact prognosis.
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d-Serine Degradation by Proteus Mirabilis Contributes to Fitness during Single-Species and Polymicrobial Catheter-Associated Urinary Tract Infection
American Society for Microbiology, 2019Co-Authors: Aimee L. Brauer, Alexandra O Johnson, Ashley N. White, Brian S. Learman, Chelsie E ArmbrusterAbstract:Urinary tract infections are among the most common health care-associated infections worldwide, the majority of which involve a urinary catheter (CAUTI). Our recent investigation of CAUTIs in nursing home residents identified Proteus Mirabilis, Enterococcus species, and Escherichia coli as the three most common organisms. These infections are also often polymicrobial, and we identified Morganella morganii, Enterococcus species, and Providencia stuartii as being more prevalent during polymicrobial CAUTI than single-species infection. Our research therefore focuses on identifying “core” fitness factors that are highly conserved in P. Mirabilis and that contribute to infection regardless of the presence of these other organisms. In this study, we determined that the ability to degrade d-serine, the most abundant d-amino acid in urine and serum, strongly contributes to P. Mirabilis fitness within the urinary tract, even when competing for nutrients with another organism. d-Serine uptake and degradation therefore represent potential targets for disruption of P. Mirabilis infections.Proteus Mirabilis is a common cause of catheter-associated urinary tract infection (CAUTI) and secondary bacteremia, which are frequently polymicrobial. We previously utilized transposon insertion-site sequencing (Tn-Seq) to identify novel fitness factors for colonization of the catheterized urinary tract during single-species and polymicrobial infection, revealing numerous metabolic pathways that may contribute to P. Mirabilis fitness regardless of the presence of other cocolonizing organisms. One such “core” fitness factor was d-serine utilization. In this study, we generated isogenic mutants in d-serine dehydratase (dsdA), d-serine permease (dsdX), and the divergently transcribed activator of the operon (dsdC) to characterize d-serine utilization in P. Mirabilis and explore the contribution of this pathway to fitness during single-species and polymicrobial infection. P. Mirabilis was capable of utilizing either d- or l-serine as a sole carbon or nitrogen source, and dsdA, dsdX, and dsdC were each specifically required for d-serine degradation. This capability was highly conserved among P. Mirabilis isolates, although not universal among uropathogens: Escherichia coli and Morganella morganii utilized d-serine, while Providencia stuartii and Enterococcus faecalis did not. d-Serine utilization did not contribute to P. Mirabilis growth in urine ex vivo during a 6-h time course but significantly contributed to fitness during single-species and polymicrobial CAUTI during a 96-h time course, regardless of d-serine utilization by the coinfecting isolate. d-Serine utilization also contributed to secondary bacteremia during CAUTI as well as survival in a direct bacteremia model. Thus, we propose d-serine utilization as a core fitness factor in P. Mirabilis and a possible target for disruption of infection
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genome wide transposon mutagenesis of proteus Mirabilis essential genes fitness factors for catheter associated urinary tract infection and the impact of polymicrobial infection on fitness requirements
PLOS Pathogens, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Valerie Forsythdeornellas, Alexandra O Johnson, Lili Zhao, Weisheng Wu, Harry L. T. MobleyAbstract:The Gram-negative bacterium Proteus Mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs), which are often polymicrobial. Numerous prior studies have uncovered virulence factors for P. Mirabilis pathogenicity in a murine model of ascending UTI, but little is known concerning pathogenesis during CAUTI or polymicrobial infection. In this study, we utilized five pools of 10,000 transposon mutants each and transposon insertion-site sequencing (Tn-Seq) to identify the full arsenal of P. Mirabilis HI4320 fitness factors for single-species versus polymicrobial CAUTI with Providencia stuartii BE2467. 436 genes in the input pools lacked transposon insertions and were therefore concluded to be essential for P. Mirabilis growth in rich medium. 629 genes were identified as P. Mirabilis fitness factors during single-species CAUTI. Tn-Seq from coinfection with P. stuartii revealed 217/629 (35%) of the same genes as identified by single-species Tn-Seq, and 1353 additional factors that specifically contribute to colonization during coinfection. Mutants were constructed in eight genes of interest to validate the initial screen: 7/8 (88%) mutants exhibited the expected phenotypes for single-species CAUTI, and 3/3 (100%) validated the expected phenotypes for polymicrobial CAUTI. This approach provided validation of numerous previously described P. Mirabilis fitness determinants from an ascending model of UTI, the discovery of novel fitness determinants specifically for CAUTI, and a stringent assessment of how polymicrobial infection influences fitness requirements. For instance, we describe a requirement for branched-chain amino acid biosynthesis by P. Mirabilis during coinfection due to high-affinity import of leucine by P. stuartii. Further investigation of genes and pathways that provide a competitive advantage during both single-species and polymicrobial CAUTI will likely provide robust targets for therapeutic intervention to reduce P. Mirabilis CAUTI incidence and severity.
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the pathogenic potential of proteus Mirabilis is enhanced by other uropathogens during polymicrobial urinary tract infection
Infection and Immunity, 2017Co-Authors: Chelsie E Armbruster, Sara N Smith, Alejandra Yep, Alexandra O Johnson, Weisheng Wu, Kathryn A Eaton, Valerie Deornellas, Lona Mody, Harry L. T. MobleyAbstract:ABSTRACT Urinary catheter use is prevalent in health care settings, and polymicrobial colonization by urease-positive organisms, such as Proteus Mirabilis and Providencia stuartii, commonly occurs with long-term catheterization. We previously demonstrated that coinfection with P. Mirabilis and P. stuartii increased overall urease activity in vitro and disease severity in a model of urinary tract infection (UTI). In this study, we expanded these findings to a murine model of catheter-associated UTI (CAUTI), delineated the contribution of enhanced urease activity to coinfection pathogenesis, and screened for enhanced urease activity with other common CAUTI pathogens. In the UTI model, mice coinfected with the two species exhibited higher urine pH values, urolithiasis, bacteremia, and more pronounced tissue damage and inflammation compared to the findings for mice infected with a single species, despite having a similar bacterial burden within the urinary tract. The presence of P. stuartii, regardless of urease production by this organism, was sufficient to enhance P. Mirabilis urease activity and increase disease severity, and enhanced urease activity was the predominant factor driving tissue damage and the dissemination of both organisms to the bloodstream during coinfection. These findings were largely recapitulated in the CAUTI model. Other uropathogens also enhanced P. Mirabilis urease activity in vitro , including recent clinical isolates of Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. We therefore conclude that the underlying mechanism of enhanced urease activity may represent a widespread target for limiting the detrimental consequences of polymicrobial catheter colonization, particularly by P. Mirabilis and other urease-positive bacteria.
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increased incidence of urolithiasis and bacteremia during proteus Mirabilis and providencia stuartii coinfection due to synergistic induction of urease activity
The Journal of Infectious Diseases, 2014Co-Authors: Chelsie E Armbruster, Sara N Smith, Alejandra Yep, Harry L. T. MobleyAbstract:Catheter-associated urinary tract infection (CaUTI), the most common health care-associated infection worldwide, accounts for up to 40% of hospital-acquired infections [1]. Data compiled over the last 30 years indicate that up to 86% of CaUTIs are polymicrobial, involving combinations of Proteus Mirabilis, Providencia stuartii, Morganella morganii, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae [2–9]. P. Mirabilis and P. stuartii are two of the most common causes of CaUTI, and the most consistently found to co-colonize [2, 5, 6, 8–10]. Both species are resistant to numerous antibiotics and have a remarkable ability to persist within the urinary tract despite catheter changes and antibiotic treatment [5, 6, 9]. Potential complications of CaUTI caused by P. Mirabilis or P. stuartii include catheter blockage and urolithiasis due to urease activity. P. Mirabilis is thought to be the main species responsible for crystalline biofilm formation on catheters and the resulting blockage, and P. stuartii is generally the second most common species isolated from blocked indwelling catheters [6, 10, 11]. Experimentally, a high inoculum of P. Mirabilis (2 × 1010 CFU/mL) results in urolithiasis and severe pyelonephritis, while loss of urease activity severely reduces colonization, prevents stone formation, and limits kidney damage, indicating that urease is a major contributing factor to both the severity and persistence of P. Mirabilis UTI [12–16]. P. stuartii BE2467 appears to possess two seemingly identical urease enzymes, one plasmid-encoded and one chromosomal [17], although the specific contribution of P. stuartii urease to colonization and severity of infection has yet to be addressed. Notably, urease activity in both of these species is induced by the presence of urea [18–20]. Bacteremia is another complication of P. Mirabilis and P. stuartii CaUTI. In long term care facilities, bacteriuria is the source for 45%–55% of bacteremias [1]. Indeed, UTI is a common source of bacteremia for both P. Mirabilis and P. stuartii [21–26]. Similar to bacteriuria, bacteremia in patients with long-term catheterization is also frequently polymicrobial [1, 26, 27]. It has been reported that 25% of P. Mirabilis bacteremias and up to 51% of P. stuartii bacteremias are polymicrobial [22, 25, 28], suggesting that P. stuartii and P. Mirabilis may promote development of bacteremia by other species or are more likely to reach the bloodstream during a polymicrobial infection. This is notable as the mortality rate for polymicrobial bacteremia is increased compared to the already high mortality rate of P. Mirabilis or P. stuartii monospecies bacteremia [25, 26]. Despite the staggering data suggesting co-colonization and possible cooperation between P. Mirabilis and P. stuartii, the impact of coinfection by these species has yet to be addressed experimentally. In this study, we used a mouse model of ascending UTI to determine the impact of P. Mirabilis and P. stuartii coinfection on bacterial persistence, bacteremia, and urolithiasis, as well as the impact of urease on these parameters. The results clearly demonstrate that coinfection increases the incidence of urolithiasis and bacteremia in a urease-dependent manner and indicate synergistic induction of urease activity during co-culture.
Jessica N Schaffer - One of the best experts on this subject based on the ideXlab platform.
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proteus Mirabilis fimbriae and urease dependent clusters assemble in an extracellular niche to initiate bladder stone formation
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Jessica N Schaffer, Allison N Norsworthy, Tungtien Sun, Melanie M PearsonAbstract:The catheter-associated uropathogen Proteus Mirabilis frequently causes urinary stones, but little has been known about the initial stages of bladder colonization and stone formation. We found that P. Mirabilis rapidly invades the bladder urothelium, but generally fails to establish an intracellular niche. Instead, it forms extracellular clusters in the bladder lumen, which form foci of mineral deposition consistent with development of urinary stones. These clusters elicit a robust neutrophil response, and we present evidence of neutrophil extracellular trap generation during experimental urinary tract infection. We identified two virulence factors required for cluster development: urease, which is required for urolithiasis, and mannose-resistant Proteus-like fimbriae. The extracellular cluster formation by P. Mirabilis stands in direct contrast to uropathogenic Escherichia coli, which readily formed intracellular bacterial communities but not luminal clusters or urinary stones. We propose that extracellular clusters are a key mechanism of P. Mirabilis survival and virulence in the bladder.
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proteus Mirabilis and urinary tract infections
Microbiology spectrum, 2015Co-Authors: Jessica N Schaffer, Melanie M PearsonAbstract:Proteus Mirabilis is a Gram-negative bacterium and is well known for its ability to robustly swarm across surfaces in a striking bulls’-eye pattern. Clinically, this organism is most frequently a pathogen of the urinary tract, particularly in patients undergoing long-term catheterization. This review covers P. Mirabilis with a focus on urinary tract infections (UTI), including disease models, vaccine development efforts, and clinical perspectives. Flagella-mediated motility, both swimming and swarming, is a central facet of this organism. The regulation of this complex process and its contribution to virulence is discussed, along with the type VI-secretion system-dependent intra-strain competition, which occurs during swarming. P. Mirabilis uses a diverse set of virulence factors to access and colonize the host urinary tract, including urease and stone formation, fimbriae and other adhesins, iron and zinc acquisition, proteases and toxins, biofilm formation, and regulation of pathogenesis. While significant advances in this field have been made, challenges remain to combatting complicated UTI and deciphering P. Mirabilis pathogenesis.
