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Yang J, Zhang L, He X, Gou X, Zong Z, Luo Y. In vitro and in vivo enhancement effect of glabridin on the antibacterial activity of colistin, against multidrug resistant Escherichia coli strains. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 130:155732. [PMID: 38776738 DOI: 10.1016/j.phymed.2024.155732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/19/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND The increase in antimicrobial resistance leads to complications in treatments, prolonged hospitalization, and increased mortality. Glabridin (GLA) is a hydroxyisoflavan from Glycyrrhiza glabra L. that exhibits multiple pharmacological activities. Colistin (COL), a last-resort antibiotic, is increasingly being used in clinic against Gram-negative bacteria. Previous reports have shown that GLA is able to sensitize first line antibiotics such as norfloxacin and vancomycin on Staphylococcus aureus, implying that the use of GLA as an antibiotic adjuvant is a promising strategy for addressing the issue of drug resistance. However, the adjuvant effect on other antibiotics, especially COL, on Gram-negative bacteria such as Escherichia coli has not been studied. PURPOSE The objective of our study was to investigate the targets of GLA and the synergistic effect of GLA and COL in E. coli, and to provide further evidence for the use of GLA as an antibiotic adjuvant to alleviate the problem of drug resistance. METHODS We first investigated the interaction between GLA and enoyl-acyl carrier protein reductase, also called "FabI", through enzyme inhibition assay, differential scanning fluorimetry, isothermal titration calorimetry and molecular docking assay. We tested the transmembrane capacity of GLA on its own and combined it with several antibiotics. The antimicrobial activities of GLA and COL were evaluated against six different susceptible and resistant E. coli in vitro. Their interactions were analyzed using checkerboard assay, time-kill curve and CompuSyn software. A series of sensitivity tests was conducted in E. coli overexpressing the fabI gene. The development of COL resistance in the presence of GLA was tested. The antimicrobial efficacy of GLA and COL in a mouse model of urinary tract infection was assessed. The anti-biofilm effects of GLA and COL were investigated. RESULTS In this study, enzyme kinetic analysis and thermal analysis provided evidence for the interaction between GLA and FabI in E. coli. GLA enhanced the antimicrobial effect of COL and synergistically suppressed six different susceptible and resistant E. coli with COL. Overexpression experiments showed that targeted inhibition of FabI was a key mechanism by which GLA synergistically enhanced COL activity. The combination of GLA and COL slowed the development of COL resistance in E. coli. Combined GLA and COL treatment significantly reduced bacterial load and mitigated urinary tract injury in a mouse model of E. coli urinary tract infection. Additionally, GLA + COL inhibited the formation and eradication of biofilms and the synthesis of curli. CONCLUSION Our findings indicate that GLA synergistically enhances antimicrobial activities of COL by targeting inhibition of FabI in E. coli. GLA is expected to continue to be developed as an antibiotic adjuvant to address drug resistance issues.
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Affiliation(s)
- Jiaxing Yang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Laiying Zhang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xinlian He
- Laboratory of Human Diseases and Immunotherapy, and State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xupeng Gou
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhiyong Zong
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Youfu Luo
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
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2
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Bouhrour N, Nibbering PH, Bendali F. Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens. Pathogens 2024; 13:393. [PMID: 38787246 PMCID: PMC11124157 DOI: 10.3390/pathogens13050393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/29/2024] [Accepted: 05/04/2024] [Indexed: 05/25/2024] Open
Abstract
Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.
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Affiliation(s)
- Nesrine Bouhrour
- Laboratoire de Microbiologie Appliquée, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria;
| | - Peter H. Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, The Netherlands;
| | - Farida Bendali
- Laboratoire de Microbiologie Appliquée, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria;
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3
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Heffernan JR, Wildenthal JA, Tran H, Katumba GL, McCoy WH, Henderson JP. Yersiniabactin is a quorum-sensing autoinducer and siderophore in uropathogenic Escherichia coli. mBio 2024; 15:e0027723. [PMID: 38236035 PMCID: PMC10865836 DOI: 10.1128/mbio.00277-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 12/07/2023] [Indexed: 01/19/2024] Open
Abstract
Siderophores are secreted ferric ion chelators used to obtain iron in nutrient-limited environmental niches, including human hosts. While all Escherichia coli express the enterobactin (Ent) siderophore system, isolates from patients with urinary tract infections additionally express the genetically distinct yersiniabactin (Ybt) siderophore system. To determine whether the Ent and Ybt systems are functionally redundant for iron uptake, we compared the growth of different isogenic siderophore biosynthetic mutants in the presence of transferrin, a human iron-binding protein. We observed that Ybt expression does not compensate for deficient Ent expression following low-density inoculation. Using transcriptional and product analysis, we found this non-redundancy to be attributable to a density-dependent transcriptional stimulation cycle in which Ybt functions as an autoinducer. These results distinguish the Ybt system as a combined quorum-sensing and siderophore system. These functions may reflect Ybt as a public good within bacterial communities or as an adaptation to confined, subcellular compartments in infected hosts. This combined functionality may contribute to the extraintestinal pathogenic potential of E. coli and related Enterobacterales.IMPORTANCEPatients with urinary tract infections are often infected with Escherichia coli strains carrying adaptations that increase their pathogenic potential. One of these adaptations is the accumulation of multiple siderophore systems, which scavenge iron for nutritional use. While iron uptake is important for bacterial growth, the increased metabolic costs of siderophore production could diminish bacterial fitness during infections. In a siderophore-dependent growth condition, we show that the virulence-associated yersiniabactin siderophore system in uropathogenic E. coli is not redundant with the ubiquitous E. coli enterobactin system. This arises not from differences in iron-scavenging activity but because yersiniabactin is preferentially expressed during bacterial crowding, leaving bacteria dependent upon enterobactin for growth at low cell density. Notably, this regulatory mode arises because yersiniabactin stimulates its own expression, acting as an autoinducer in a previously unappreciated quorum-sensing system. This unexpected result connects quorum-sensing with pathogenic potential in E. coli and related Enterobacterales.
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Affiliation(s)
- James R. Heffernan
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - John A. Wildenthal
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hung Tran
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - George L. Katumba
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - William H. McCoy
- Division of Dermatology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey P. Henderson
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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4
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Zou Z, Obernuefemann CLP, Singh P, Pinkner JS, Xu W, Nye TM, Dodson KW, Almqvist F, Hultgren SJ, Caparon MG. Dihydrothiazolo ring-fused 2-pyridone antimicrobial compounds treat Streptococcus pyogenes skin and soft tissue infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.02.573960. [PMID: 38260261 PMCID: PMC10802287 DOI: 10.1101/2024.01.02.573960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
We have developed GmPcides from a peptidomimetic dihydrothiazolo ring-fused 2-pyridone scaffold that have antimicrobial activities against a broad-spectrum of Gram-positive pathogens. Here we examine the treatment efficacy of GmPcides using skin and soft tissue infection (SSTI) and biofilm formation models by Streptococcus pyogenes. Screening our compound library for minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations identified GmPcide PS757 as highly active against S. pyogenes. Treatment of S. pyogenes biofilm with PS757 revealed robust efficacy against all phases of biofilm formation by preventing initial biofilm development, ceasing biofilm maturation and eradicating mature biofilm. In a murine model of S. pyogenes SSTI, subcutaneous delivery of PS757 resulted in reduced levels of tissue damage, decreased bacterial burdens and accelerated rates of wound-healing, which were associated with down-regulation of key virulence factors, including M protein and the SpeB cysteine protease. These data demonstrate that GmPcides show considerable promise for treating S. pyogenes infections.
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Affiliation(s)
- Zongsen Zou
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Chloe L P Obernuefemann
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Pardeep Singh
- Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden
| | - Jerome S Pinkner
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Wei Xu
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Taylor M Nye
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Karen W Dodson
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | | | - Scott J Hultgren
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Michael G Caparon
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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5
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Nye TM, Zou Z, Obernuefemann CLP, Pinkner JS, Lowry E, Kleinschmidt K, Bergeron K, Klim A, Dodson KW, Flores-Mireles AL, Walker JN, Wong DG, Desai A, Caparon MG, Hultgren SJ. Microbial co-occurrences on catheters from long-term catheterized patients. Nat Commun 2024; 15:61. [PMID: 38168042 PMCID: PMC10762172 DOI: 10.1038/s41467-023-44095-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024] Open
Abstract
Catheter-associated urinary tract infections (CAUTIs), a common cause of healthcare-associated infections, are caused by a diverse array of pathogens that are increasingly becoming antibiotic resistant. We analyze the microbial occurrences in catheter and urine samples from 55 human long-term catheterized patients collected over one year. Although most of these patients were prescribed antibiotics over several collection periods, their catheter samples remain colonized by one or more bacterial species. Examination of a total of 366 catheter and urine samples identify 13 positive and 13 negative genus co-occurrences over 12 collection periods, representing associations that occur more or less frequently than expected by chance. We find that for many patients, the microbial species composition between collection periods is similar. In a subset of patients, we find that the most frequently sampled bacteria, Escherichia coli and Enterococcus faecalis, co-localize on catheter samples. Further, co-culture of paired isolates recovered from the same patients reveals that E. coli significantly augments E. faecalis growth in an artificial urine medium, where E. faecalis monoculture grows poorly. These findings suggest novel strategies to collapse polymicrobial CAUTI in long-term catheterized patients by targeting mechanisms that promote positive co-associations.
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Affiliation(s)
- Taylor M Nye
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Zongsen Zou
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Chloe L P Obernuefemann
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Jerome S Pinkner
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Erin Lowry
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Kent Kleinschmidt
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Karla Bergeron
- Department of Surgery, Division of Urologic Surgery, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Aleksandra Klim
- Department of Surgery, Division of Urologic Surgery, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Karen W Dodson
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA
| | - Ana L Flores-Mireles
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jennifer N Walker
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Daniel Garrett Wong
- Department of Surgery, Division of Urologic Surgery, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Alana Desai
- Department of Surgery, Division of Urologic Surgery, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Michael G Caparon
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA.
| | - Scott J Hultgren
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO, 63110-1093, USA.
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6
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Zou Z, Robinson JI, Steinberg LK, Henderson JP. Uropathogenic Escherichia coli wield enterobactin-derived catabolites as siderophores. J Biol Chem 2024; 300:105554. [PMID: 38072063 PMCID: PMC10788543 DOI: 10.1016/j.jbc.2023.105554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/20/2023] [Accepted: 12/05/2023] [Indexed: 12/19/2023] Open
Abstract
Uropathogenic Escherichia coli (UPEC) secrete multiple siderophore types to scavenge extracellular iron(III) ions during clinical urinary tract infections, despite the metabolic costs of biosynthesis. Here, we find the siderophore enterobactin (Ent) and its related products to be prominent components of the iron-responsive extracellular metabolome of a model UPEC strain. Using defined Ent biosynthesis and import mutants, we identify lower molecular weight dimeric exometabolites as products of incomplete siderophore catabolism, rather than prematurely released biosynthetic intermediates. In E. coli, iron acquisition from iron(III)-Ent complexes requires intracellular esterases that hydrolyze the siderophore. Although UPEC are equipped to consume the products of completely hydrolyzed Ent, we find that Ent and its derivatives may be incompletely hydrolyzed to yield products with retained siderophore activity. These results are consistent with catabolic inefficiency as means to obtain more than one iron ion per siderophore molecule. This is compatible with an evolved UPEC strategy to maximize the nutritional returns from metabolic investments in siderophore biosynthesis.
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Affiliation(s)
- Zongsen Zou
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St Louis, Missouri, USA; Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - John I Robinson
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St Louis, Missouri, USA; Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Lindsey K Steinberg
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St Louis, Missouri, USA; Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Jeffrey P Henderson
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St Louis, Missouri, USA; Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA.
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7
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Ljubetic BM, Mohammad A, Durrani B, Dobberfuhl AD. Pathophysiologic Insights into the Transition from Asymptomatic Bacteriuria to Urinary Tract Infection. Curr Urol Rep 2023; 24:533-540. [PMID: 37856072 DOI: 10.1007/s11934-023-01183-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2023] [Indexed: 10/20/2023]
Abstract
PURPOSE OF REVIEW Asymptomatic bacteriuria (ASB) can be found in the general population but it is more common in catheterized patients. Some patients develop urinary tract infections (UTI) and others stay asymptomatic throughout time. The scientific community lacks a pathophysiologic explanation of why asymptomatic bacteriuria stays asymptomatic most of the time, and why and how it sometimes transitions to UTI. In an attempt to bridge this gap in knowledge, a summary of the current literature is conducted on the pathophysiologic differences between ASB and UTI, beyond their clinical differences. RECENT FINDINGS ASB and UTI cannot be differentiated just by their phylogroup or number of virulence factors. The difference may be in their metabolism gene expression. The literature lacks a pathophysiological explanation of the transition from ASB to UTI, and recent discoveries suggest that metabolic gene expression may hold the key.
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Affiliation(s)
- Bernardita M Ljubetic
- Department of Urology, Center for Academic Medicine, Urology-5656, Stanford University School of Medicine, 453 Quarry Road, Palo Alto, CA, 94304, USA
| | - Ashu Mohammad
- Department of Urology, Center for Academic Medicine, Urology-5656, Stanford University School of Medicine, 453 Quarry Road, Palo Alto, CA, 94304, USA
| | - Butool Durrani
- Department of Internal Medicine, Aga Khan University Hospital, National Stadium Rd, Karachi, Karachi City, Pakistan
| | - Amy D Dobberfuhl
- Department of Urology, Center for Academic Medicine, Urology-5656, Stanford University School of Medicine, 453 Quarry Road, Palo Alto, CA, 94304, USA.
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8
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Maillard JY, Centeleghe I. How biofilm changes our understanding of cleaning and disinfection. Antimicrob Resist Infect Control 2023; 12:95. [PMID: 37679831 PMCID: PMC10483709 DOI: 10.1186/s13756-023-01290-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 08/15/2023] [Indexed: 09/09/2023] Open
Abstract
Biofilms are ubiquitous in healthcare settings. By nature, biofilms are less susceptible to antimicrobials and are associated with healthcare-associated infections (HAI). Resistance of biofilm to antimicrobials is multifactorial with the presence of a matrix composed of extracellular polymeric substances and eDNA, being a major contributing factor. The usual multispecies composition of environmental biofilms can also impact on antimicrobial efficacy. In healthcare settings, two main types of biofilms are present: hydrated biofilms, for example, in drains and parts of some medical devices and equipment, and environmental dry biofilms (DSB) on surfaces and possibly in medical devices. Biofilms act as a reservoir for pathogens including multi-drug resistant organisms and their elimination requires different approaches. The control of hydrated (drain) biofilms should be informed by a reduction or elimination of microbial bioburden together with measuring biofilm regrowth time. The control of DSB should be measured by a combination of a reduction or elimination in microbial bioburden on surfaces together with a decrease in bacterial transfer post-intervention. Failure to control biofilms increases the risk for HAI, but biofilms are not solely responsible for disinfection failure or shortcoming. The limited number of standardised biofilm efficacy tests is a hindrance for end users and manufacturers, whilst in Europe there are no approved standard protocols. Education of stakeholders about biofilms and ad hoc efficacy tests, often academic in nature, is thus paramount, to achieve a better control of biofilms in healthcare settings.
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Affiliation(s)
- Jean-Yves Maillard
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB, Wales, UK.
| | - Isabella Centeleghe
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB, Wales, UK
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9
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Zou Z, Robinson JI, Steinberg LK, Henderson JP. Uropathogenic Escherichia coli wield enterobactin-derived catabolites as siderophores. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550588. [PMID: 37546885 PMCID: PMC10402112 DOI: 10.1101/2023.07.25.550588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Uropathogenic E. coli (UPEC) secrete multiple siderophore types to scavenge extracellular iron(III) ions during clinical urinary tract infections, despite the metabolic costs of biosynthesis. Here we find the siderophore enterobactin and its related products to be prominent components of the iron-responsive extracellular metabolome of a model UPEC strain. Using defined enterobactin biosynthesis and import mutants, we identify lower molecular weight, dimeric exometabolites as products of incomplete siderophore catabolism, rather than prematurely released biosynthetic intermediates. In E. coli, iron acquisition from iron(III)-enterobactin complexes requires intracellular esterases that hydrolyze the siderophore. Although UPEC are equipped to consume the products of completely hydrolyzed enterobactin, we find that enterobactin and its derivatives may be incompletely hydrolyzed to yield products with retained siderophore activity. These results are consistent with catabolic inefficiency as means to obtain more than one iron ion per siderophore molecule. This is compatible with an evolved UPEC strategy to maximize the nutritional returns from metabolic investments in siderophore biosynthesis.
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Affiliation(s)
- Zongsen Zou
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - John I. Robinson
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lindsey K. Steinberg
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey P. Henderson
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
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10
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Heffernan JR, Katumba GL, McCoy WH, Henderson JP. Yersiniabactin is a quorum sensing autoinducer and siderophore in uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.09.527953. [PMID: 36798367 PMCID: PMC9934619 DOI: 10.1101/2023.02.09.527953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Siderophores are secreted ferric ion chelators used to obtain iron in nutrient-limited environmental niches, including human hosts. While all E. coli encode the enterobactin (Ent) siderophore system, isolates from patients with urinary tract infections additionally encode the genetically distinct yersiniabactin (Ybt) siderophore system. To determine whether the Ent and Ybt systems are functionally redundant for iron uptake, we compared growth of different isogenic siderophore biosynthesis mutants in the presence of transferrin, a human iron-binding protein. We observed that the Ybt system does not compensate for loss of the Ent system during siderophore-dependent, low density growth. Using transcriptional and product analysis, we found that this non-redundancy is attributable to a density-dependent transcriptional stimulation cycle in which Ybt assume an additional autoinducer function. These results distinguish the Ybt system as a combined quorum-sensing and siderophore system. These functions may reflect Ybt as a public good within bacterial communities or as an adaptation to confined, subcellular compartments in infected hosts. The efficiency of this arrangement may contribute to the extraintestinal pathogenic potential of E. coli and related Enterobacterales. IMPORTANCE Urinary tract infections (UTIs) are one of the most common human bacterial infections encountered by physicians. Adaptations that increase the pathogenic potential of commensal microbes such as E.coli are of great interest. One potential adaptation observed in clinical isolates is accumulation of multiple siderophore systems, which scavenge iron for nutritional use. While iron uptake is important for bacterial growth, the increased metabolic costs of siderophore production could diminish bacterial fitness during infections. In a siderophore-dependent growth conditions, we show that the virulence-associated yersiniabactin siderophore system in uropathogenic E. coli is not redundant with the ubiquitous E. coli enterobactin system. This arises not from differences in iron scavenging activity but because yersiniabactin is preferentially expressed during bacterial crowding, leaving bacteria dependent upon enterobactin for growth at low cell density. Notably, this regulatory mode arises because yersiniabactin stimulates its own expression, acting as an autoinducer in a previously unappreciated quorum-sensing system. This unexpected result connects quorum-sensing with pathogenic potential in E. coli and related Enterobacterales.
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