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Krewing M, Mönch E, Bolten A, Niesalla H. Resistance or tolerance? Highlighting the need for precise terminology in the field of disinfection. J Hosp Infect 2024; 150:51-60. [PMID: 38782058 DOI: 10.1016/j.jhin.2024.05.006] [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: 12/19/2023] [Revised: 04/24/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
The terms 'resistance' and 'tolerance' are well defined in the context of antibiotic research. However, in the field of disinfection, these terms are often used synonymously, which creates ambiguity and can lead to misunderstandings and misconceptions. In addition, this inconsistency in terminology makes it difficult to assess the risk of a disinfectant resistance. This general review aims to discuss existing definitions of the terms 'adaptation', 'susceptibility', 'tolerance', 'persistence' and 'resistance' in the light of disinfectants. The most ambiguity is found between tolerance and resistance. Whereas the former describes the not necessarily heritable survival of transient exposure to usually lethal concentrations, resistance is the strictly heritable ability to survive otherwise lethal concentrations of an antimicrobial agent, regardless of exposure time. A simple transfer of experience from antibiotic research is not recommended when assessing the risk of resistance to disinfectants, as there are important differences between antibiotics and disinfectants, although both are antimicrobials: (i) disinfectants are usually applied at concentrations that exceed the minimum inhibitory concentration by orders of magnitude, (ii) the exposure times of disinfectants are in the range of seconds, minutes, or a few hours, (iii) the mode of action of disinfectants is less specific, and (iv) disinfectants often contain more than one active agent with additive or synergistic effects. It is important to recognize that disinfectants, like other antimicrobial agents such as antibiotics, have a dualistic nature and should be used correctly and with caution.
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Affiliation(s)
- M Krewing
- Hartmann Science Center, BODE Chemie GmbH - a Company of the Hartmann Group, Hamburg, Germany.
| | - E Mönch
- BODE Chemie GmbH - a Company of the Hartmann Group, Hamburg, Germany
| | - A Bolten
- BODE Chemie GmbH - a Company of the Hartmann Group, Hamburg, Germany
| | - H Niesalla
- Hartmann Science Center, BODE Chemie GmbH - a Company of the Hartmann Group, Hamburg, Germany
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Colomer-Winter C, Yong AMH, Chong KKL, Veleba M, Choo PY, Gao IH, Matysik A, Ho FK, Chen SL, Kline KA. The HtrA chaperone monitors sortase-assembled pilus biogenesis in Enterococcus faecalis. PLoS Genet 2024; 20:e1011071. [PMID: 39102428 PMCID: PMC11326707 DOI: 10.1371/journal.pgen.1011071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 08/15/2024] [Accepted: 07/09/2024] [Indexed: 08/07/2024] Open
Abstract
Sortase-assembled pili contribute to virulence in many Gram-positive bacteria. In Enterococcus faecalis, the endocarditis and biofilm-associated pilus (Ebp) is polymerized on the membrane by sortase C (SrtC) and attached to the cell wall by sortase A (SrtA). In the absence of SrtA, polymerized pili remain anchored to the membrane (i.e. off-pathway). Here we show that the high temperature requirement A (HtrA) bifunctional chaperone/protease of E. faecalis is a quality control system that clears aberrant off-pathway pili from the cell membrane. In the absence of HtrA and SrtA, accumulation of membrane-bound pili leads to cell envelope stress and partially induces the regulon of the ceftriaxone resistance-associated CroRS two-component system, which in turn causes hyper-piliation and cell morphology alterations. Inactivation of croR in the OG1RF ΔsrtAΔhtrA background partially restores the observed defects of the ΔsrtAΔhtrA strain, supporting a role for CroRS in the response to membrane perturbations. Moreover, absence of SrtA and HtrA decreases basal resistance of E. faecalis against cephalosporins and daptomycin. The link between HtrA, pilus biogenesis and the CroRS two-component system provides new insights into the E. faecalis response to endogenous membrane perturbations.
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Affiliation(s)
- Cristina Colomer-Winter
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Adeline M H Yong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Kelvin K L Chong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Mark Veleba
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Pei Yi Choo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Iris Hanxing Gao
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Artur Matysik
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Foo Kiong Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Swaine L Chen
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Genome #02-01, Singapore, Singapore
| | - Kimberly A Kline
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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Snell A, Manias DA, Elbehery RR, Dunny GM, Willett JLE. Arginine impacts aggregation, biofilm formation, and antibiotic susceptibility in Enterococcus faecalis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596650. [PMID: 38853917 PMCID: PMC11160706 DOI: 10.1101/2024.05.30.596650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Enterococcus faecalis is a commensal bacterium in the gastrointestinal tract (GIT) of humans and other organisms. E. faecalis also causes infections in root canals, wounds, the urinary tract, and on heart valves. E. faecalis metabolizes arginine through the arginine deiminase (ADI) pathway, which converts arginine to ornithine and releases ATP, ammonia, and CO2. E. faecalis arginine metabolism also affects virulence of other pathogens during co-culture. E. faecalis may encounter elevated levels of arginine in the GIT or the oral cavity, where arginine is used as a dental therapeutic. Little is known about how E. faecalis responds to growth in arginine in the absence of other bacteria. To address this, we used RNAseq and additional assays to measure growth, gene expression, and biofilm formation in E. faecalis OG1RF grown in arginine. We demonstrate that arginine decreases E. faecalis biofilm production and causes widespread differential expression of genes related to metabolism, quorum sensing, and polysaccharide synthesis. Growth in arginine also increases aggregation of E. faecalis and promotes decreased susceptibility to the antibiotics ampicillin and ceftriaxone. This work provides a platform for understanding of how the presence of arginine in biological niches affects E. faecalis physiology and virulence of surrounding microbes.
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Affiliation(s)
- Alex Snell
- University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Dawn A. Manias
- University of Minnesota Medical School, Minneapolis, MN, 55455
| | | | - Gary M. Dunny
- University of Minnesota Medical School, Minneapolis, MN, 55455
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4
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Jennings KC, Johnson KE, Hayward MA, Kristich CJ, Salzman NH. CCR2-dependent CX3CR1+ colonic macrophages promote Enterococcus faecalis dissemination. Infect Immun 2024; 92:e0000624. [PMID: 38629806 PMCID: PMC11075457 DOI: 10.1128/iai.00006-24] [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: 01/05/2024] [Accepted: 03/29/2024] [Indexed: 05/08/2024] Open
Abstract
Enterococci are common commensal bacteria that colonize the gastrointestinal tracts of most mammals, including humans. Importantly, these bacteria are one of the leading causes of nosocomial infections. This study examined the role of colonic macrophages in facilitating Enterococcus faecalis infections in mice. We determined that depletion of colonic phagocytes resulted in the reduction of E. faecalis dissemination to the gut-draining mesenteric lymph nodes. Furthermore, we established that trafficking of monocyte-derived CX3CR1-expressing macrophages contributed to E. faecalis dissemination in a manner that was not reliant on CCR7, the conventional receptor involved in lymphatic migration. Finally, we showed that E. faecalis mutants with impaired intracellular survival exhibited reduced dissemination, suggesting that E. faecalis can exploit host immune cell migration to disseminate systemically and cause disease. Our findings indicate that modulation of macrophage trafficking in the context of antibiotic therapy could serve as a novel approach for preventing or treating opportunistic infections by disseminating enteric pathobionts like E. faecalis.
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Affiliation(s)
- Kevin C. Jennings
- Department of Pediatrics, Division of Gastroenterology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kaitlin E. Johnson
- Department of Pediatrics, Division of Gastroenterology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michael A. Hayward
- Department of Pediatrics, Division of Gastroenterology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christopher J. Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Nita H. Salzman
- Department of Pediatrics, Division of Gastroenterology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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5
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Luna-Bulbarela A, Romero-Gutiérrez MT, Tinoco-Valencia R, Ortiz E, Martínez-Romero ME, Galindo E, Serrano-Carreón L. Response of Bacillus velezensis 83 to interaction with Colletotrichum gloeosporioides resembles a Greek phalanx-style formation: A stress resistant phenotype with antibiosis capacity. Microbiol Res 2024; 280:127592. [PMID: 38199003 DOI: 10.1016/j.micres.2023.127592] [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: 10/13/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024]
Abstract
Plant growth-promoting rhizobacteria, such as Bacillus spp., establish beneficial associations with plants and may inhibit the growth of phytopathogenic fungi. However, these bacteria are subject to multiple biotic stimuli from their competitors, causing stress and modifying their development. This work is a study of an in vitro interaction between two model microorganisms of socioeconomic relevance, using population dynamics and transcriptomic approaches. Co-cultures of Bacillus velezensis 83 with the phytopathogenic fungus Colletotrichum gloeosporioides 09 were performed to evaluate the metabolic response of the bacteria under conditions of non-nutritional limitation. The bacterial response was associated with the induction of a stress-resistant phenotype, characterized by a lower specific growth rate, but with antimicrobial production capacity. About 12% of co-cultured B. velezensis 83 coding sequences were differentially expressed, including the up-regulation of the general stress response (sigB regulon), and the down-regulation of alternative carbon sources catabolism (glucose preference). Defense strategies in B. velezensis are a determining factor in order to preserve the long-term viability of its population. Mostly, the presence of the fungus does not affect the expression of antibiosis genes, except for those corresponding to surfactin/bacillomycin D production. Indeed, the up-regulation of antibiosis genes expression is associated with bacterial growth, regardless of the presence of the fungus. This behavior in B. velezensis 83 resembles the strategy used by the classical Greek phalanx formation: by sacrificing growth rate and metabolic versatility, resources can be redistributed to defense (stress resistant phenotype) while maintaining the attack (antibiosis capacity). The presented results are the first characterization of the molecular phenotype at the transcriptome level of a biological control agent under biotic stress caused by a phytopathogen without nutrient limitation.
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Affiliation(s)
- Agustín Luna-Bulbarela
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico; Agro&Biotecnia S. de R.L. de C.V., Limones 8, Amate Redondo, 62334 Cuernavaca, Morelos, Mexico
| | - María Teresa Romero-Gutiérrez
- Technological Innovation Department, Tlajomulco University Center, University of Guadalajara, 45641 Tlajomulco de Zúñiga, Jalisco, Mexico; Translational Bioengineering Department, Exact Sciences and Engineering University Center, Universidad de Guadalajara, Blvd. Marcelino García Barragán #1421, 44430 Guadalajara, Jalisco, Mexico
| | - Raunel Tinoco-Valencia
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico
| | - Ernesto Ortiz
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico
| | - María Esperanza Martínez-Romero
- Ecología Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Av. Universidad s/n, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico
| | - Enrique Galindo
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico; Agro&Biotecnia S. de R.L. de C.V., Limones 8, Amate Redondo, 62334 Cuernavaca, Morelos, Mexico
| | - Leobardo Serrano-Carreón
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico; Agro&Biotecnia S. de R.L. de C.V., Limones 8, Amate Redondo, 62334 Cuernavaca, Morelos, Mexico.
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Li Y, Li B, Guo X, Wang H, Cheng L. Applications of quaternary ammonium compounds in the prevention and treatment of oral diseases: State-of-the-art and future directions. J Dent 2023; 137:104678. [PMID: 37634613 DOI: 10.1016/j.jdent.2023.104678] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023] Open
Abstract
OBJECTIVES The aim of this review is to comprehensively summarize the state-of-the-art developments of quaternary ammonium compounds (QACs) in the prevention and treatment of oral diseases. By discussing the structural diversity and the potential killing mechanism, we try to offer some insights for the future research of QACs. DATA, SOURCES & STUDY SELECTION A literature search was conducted in electronic databases (Web of Science, PubMed, Medline, and Scopus). Publications that involved the applications of QACs, especially those related to the prevention and treatment of oral diseases, are included. RESULTS We have reviewed the relevant research on QACs over the past two decades. The research results indicate that the current applications are mainly focused on dental material modification and direct pharmacological interventions. Concurrently, challenges such as potential risks to normal tissues and impediments in drug resistance and microbial persistence present certain application constraints. The latest studies have encompassed the exploration of smart materials and nanoparticle formulations. CONCLUSIONS The killing mechanism may possess a threshold related to charge density. However, the exact process remains enigmatic. The structural diversity and the exploration of intelligent materials and nanoparticle formulations provide directions in development of novel QACs. CLINICAL SIGNIFICANCE The intricate oral anatomy, combined with the multifaceted oral microbiome, necessitates specialized materials for the targeted prevention and treatment of oral pathologies. QACs represent a cohort of compounds distinguished by potent anti-infective and anti-tumor attributes. Innovations in intelligent materials and nanoparticle formulations amplify their potential in significantly advancing the prevention and therapeutic interventions for oral diseases.
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Affiliation(s)
- Yiling Li
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
| | - Bolei Li
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xiao Guo
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
| | - Haohao Wang
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China.
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7
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Robertson EB, Willett JLE. Streptococcus mutans inhibits the growth of Enterococcus via the non-ribosomal cyclic peptide mutanobactin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557362. [PMID: 37745448 PMCID: PMC10515869 DOI: 10.1101/2023.09.12.557362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Enterococcus faecalis is a Gram-positive commensal bacterium in the gastrointestinal tract and an opportunistic pathogen. Enterococci are a leading cause of nosocomial infections, treatment of which is complicated by intrinsic and acquired antibiotic resistance mechanisms. Additionally, E. faecalis has been associated with various oral diseases, and it is frequently implicated in the failure of endodontic treatment. For establishment and persistence in a microbial community, E. faecalis must successfully compete against other bacteria. Streptococcal species play an important role in the establishment of the oral microbiome and co-exist with Enterococcus in the small intestine, yet the nature of interactions between E. faecalis and oral streptococci remains unclear. Here, we describe a mechanism by which Streptococcus mutans inhibits the growth of E. faecalis and other Gram-positive pathogens through the production of mutanobactin, a cyclic lipopeptide. Mutanobactin is produced by a polyketide synthase-nonribosomal peptide synthetase hybrid system encoded by the mub locus. Mutanobactin-producing S. mutans inhibits planktonic and biofilm growth of E. faecalis and is also active against other Enterococcus species and Staphylococcus aureus. Mutanobactin damages the cell envelope of E. faecalis, similar to other lipopeptide antibiotics like daptomycin. E. faecalis resistance to mutanobactin is mediated by the virulence factor gelatinase, a secreted metalloprotease. Our results highlight the anti-biofilm potential of the microbial natural product mutanobactin, provide insight into how E. faecalis interacts with other organisms in the human microbiome, and demonstrate the importance of studying E. faecalis dynamics within polymicrobial communities.
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Affiliation(s)
- Ethan B. Robertson
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455 USA
| | - Julia L. E. Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455 USA
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M S, N RP, Rajendrasozhan S. Bacterial redox response factors in the management of environmental oxidative stress. World J Microbiol Biotechnol 2022; 39:11. [PMID: 36369499 DOI: 10.1007/s11274-022-03456-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
Abstract
Bacteria evolved to survive in the available environmental chemosphere via several cellular mechanisms. A rich pool of antioxidants and stress regulators plays a significant role in the survival of bacteria in unfavorable environmental conditions. Most of the microbes exhibit resistant phenomena in toxic environment niches. Naturally, bacteria possess efficient thioredoxin reductase, glutaredoxin, and peroxiredoxin redox systems to handle environmental oxidative stress. Further, an array of transcriptional regulators senses the oxidative stress conditions. Transcription regulators, such as OxyR, SoxRS, PerR, UspA, SsrB, MarA, OhrR, SarZ, etc., sense and transduce bacterial oxidative stress responses. The redox-sensitive transcription regulators continuously recycle the utilized antioxidant enzymes during oxidative stress. These regulators promote the expression of antioxidant enzymes such as superoxide dismutase, catalase, and peroxides that overcome oxidative insults. Therefore, the transcriptional regulations maintain steady-state activities of antioxidant enzymes representing the resistance against host cell/environmental oxidative insults. Further, the redox system provides reducing equivalents to synthesize biomolecules, thereby contributing to cellular repair mechanisms. The inactive transcriptional regulators in the undisturbed cells are activated by oxidative stress. The oxidized transcriptional regulators modulate the expression of antioxidant and cellular repair enzymes to survive in extreme environmental conditions. Therefore, targeting these antioxidant systems and response regulators could alter cellular redox homeostasis. This review presents the mechanisms of different redox systems that favor bacterial survival in extreme environmental oxidative stress conditions.
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Affiliation(s)
- Sudharsan M
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, Chidambaram, Tamil Nadu, 608 002, India
| | - Rajendra Prasad N
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, Chidambaram, Tamil Nadu, 608 002, India.
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Yang J, Ren X, Zhang X, Wang X, Zhang R, Bai P, Du B, Li L, Zhao S, Qin Y, Zhang R. Mechanistic and kinetic insights into size-dependent activity in ultra-small Pt/CNTs nanozymes during antibacterial process. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.104238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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10
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Timmler SB, Kellogg SL, Atkinson SN, Little JL, Djorić D, Kristich CJ. CroR Regulates Expression of pbp4(5) to Promote Cephalosporin Resistance in Enterococcus faecalis. mBio 2022; 13:e0111922. [PMID: 35913163 PMCID: PMC9426447 DOI: 10.1128/mbio.01119-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/14/2022] [Indexed: 11/30/2022] Open
Abstract
Enterococcus faecalis is an opportunistic pathogen and a major cause of severe nosocomial infections. Treatment options against enterococcal infections are declining due to the resistance of enterococci to numerous antibiotics. A key risk factor for developing enterococcal infections is treatment with cephalosporin antibiotics, to which enterococci are intrinsically resistant. For susceptible organisms, cephalosporins inhibit bacterial growth by acylating the active site of penicillin-binding proteins (PBPs), key enzymes that catalyze peptidoglycan cross-linking. Two specific PBPs of enterococci, Pbp4(5) and PbpA(2b), exhibit low reactivity toward cephalosporins, allowing these PBPs to cross-link peptidoglycan in the presence of cephalosporins to drive resistance in enterococci, but the mechanisms by which these PBPs are regulated are poorly understood. The CroS/R two-component signal transduction system (TCS) is also required for cephalosporin resistance. Activation of CroS/R by cephalosporins leads to CroR-dependent changes in gene expression. However, the specific genes regulated by CroS/R that are responsible for cephalosporin resistance remain largely unknown. In this study, we characterized CroR-dependent transcriptome remodeling by RNA-seq, identifying pbp4(5) as a CroR regulon member in multiple, diverse lineages of E. faecalis. Through genetic analysis of the pbp4(5) and croR promoters, we uncovered a CroR-dependent regulatory motif. Mutations in this motif to disrupt CroR-dependent upregulation of pbp4(5) in the presence of cell wall stress resulted in a reduction of resistance to cephalosporins in E. faecalis, demonstrating that enhanced production of Pbp4(5) and likely other proteins involved in peptidoglycan biogenesis by the CroS/R system drives enterococcal cephalosporin resistance. IMPORTANCE Investigation into molecular mechanisms used by enterococci to subvert cephalosporin antibiotics is imperative for preventing and treating life-threatening infections. In this study, we used genetic means to investigate the functional output of the CroS/R TCS required for enterococcal resistance to cephalosporins. We found that enhanced production of the penicillin-binding protein Pbp4(5) upon exposure to cell wall stress was mediated by CroS/R and was critical for intrinsic cephalosporin resistance of E. faecalis.
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Affiliation(s)
- Sarah B. Timmler
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Stephanie L. Kellogg
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Samantha N. Atkinson
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Jaime L. Little
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Dušanka Djorić
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christopher J. Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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11
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Antimicrobial tolerance and its role in the development of resistance: Lessons from enterococci. Adv Microb Physiol 2022; 81:25-65. [PMID: 36167442 DOI: 10.1016/bs.ampbs.2022.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacteria have developed resistance against every antimicrobial in clinical use at an alarming rate. There is a critical need for more effective use of antimicrobials to both extend their shelf life and prevent resistance from arising. Significantly, antimicrobial tolerance, i.e., the ability to survive but not proliferate during antimicrobial exposure, has been shown to precede the development of bona fide antimicrobial resistance (AMR), sparking a renewed and rapidly increasing interest in this field. As a consequence, problematic infections for the first time are now being investigated for antimicrobial tolerance, with increasing reports demonstrating in-host evolution of antimicrobial tolerance. Tolerance has been identified in a wide array of bacterial species to all bactericidal antimicrobials. Of particular interest are enterococci, which contain the opportunistic bacterial pathogens Enterococcus faecalis and Enterococcus faecium. Enterococci are one of the leading causes of hospital-acquired infection and possess intrinsic tolerance to a number of antimicrobial classes. Persistence of these infections in the clinic is of growing concern, particularly for the immunocompromised. Here, we review current known mechanisms of antimicrobial tolerance, and include an in-depth analysis of those identified in enterococci with implications for both the development and prevention of AMR.
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12
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Identification of Enterococcus faecalis in Different Clonal Lineages with the Pulsed-Field Gel Electrophoresis Method in Imam Khomeini Hospital, Ilam, Iran. Jundishapur J Microbiol 2021. [DOI: 10.5812/jjm.118955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Due to the importance of identifying the source of infectious agents, different typing methods have been developed, among which the pulsed-field gel electrophoresis (PFGE) method is known as the gold standard for bacteria. Also, Enterococcus faecalis is classified as a nosocomial infection. Objectives: The current study aimed to identify the source of E. faecalis by the PFGE method. Methods: Bacteria were collected from all cases of urinary tract infections. Then, the identification process was performed. All isolates were evaluated for vancomycin resistance, and then PFGE was carried out. Results: The results of disk diffusion showed that 54% of the isolates showed resistance to vancomycin. Also, 4% of the isolates were intermediate, and 42% showed sensitivity to vancomycin. Afterwards, the PCR of the VanA gene was performed to confirm the results of disk diffusion. Thus, 48 out of 54 (88.8%) isolates had the VanA gene, and none of the four intermediate isolates had the VanA gene. Our results demonstrated that 54 isolates were vancomycin-resistant, and 50 different pulsotypes groups were identified. Conclusions: Our findings showed the isolates of E. faecalis were from different clonal lineages.
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13
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Chen Y, Wang P, Hao H, Hong J, Li H, Ji S, Li A, Gao R, Dong J, Han X, Liang M, Wang D, Li Y. Thermal Atomization of Platinum Nanoparticles into Single Atoms: An Effective Strategy for Engineering High-Performance Nanozymes. J Am Chem Soc 2021; 143:18643-18651. [PMID: 34726407 DOI: 10.1021/jacs.1c08581] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Although great progress has been made in artificial enzyme engineering, their catalytic performance is far from satisfactory as alternatives of natural enzymes. Here, we report a novel and efficient strategy to access high-performance nanozymes via direct atomization of platinum nanoparticles (Pt NPs) into single atoms by reversing the thermal sintering process. Atomization of Pt NPs into single atoms makes metal catalytic sites fully exposed and results in engineerable structural and electronic properties, thereby leading to dramatically enhanced enzymatic performance. As expected, the as-prepared thermally stable Pt single-atom nanozyme (PtTS-SAzyme) exhibited remarkable peroxidase-like catalytic activity and kinetics, far exceeding the Pt nanoparticle nanozyme. The following density functional theory calculations revealed that the engineered P and S atoms not only promote the atomization process from Pt NPs into PtTS-SAzyme but also endow single-atom Pt catalytic sites with a unique electronic structure owing to the electron donation of P atoms, as well as the electron acceptance of N and S atoms, which simultaneously contribute to the substantial enhancement of the enzyme-like catalytic performance of PtTS-SAzyme. This work demonstrates that thermal atomization of the metal nanoparticle-based nanozymes into single-atom nanozymes is an effective strategy for engineering high-performance nanozymes, which opens up a new way to rationally design and optimize artificial enzymes to mimic natural enzymes.
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Affiliation(s)
- Yuanjun Chen
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Peixia Wang
- Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Haigang Hao
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
| | - Juanji Hong
- Experimental Center of Advanced Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Haijing Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Shufang Ji
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ang Li
- Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100024, China
| | - Rui Gao
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
| | - Juncai Dong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaodong Han
- Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100024, China
| | - Minmin Liang
- Experimental Center of Advanced Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Dingsheng Wang
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yadong Li
- Department of Chemistry, Tsinghua University, Beijing 100084, China
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Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis. mBio 2020; 11:mBio.01101-20. [PMID: 33082254 PMCID: PMC7587440 DOI: 10.1128/mbio.01101-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Enterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology. Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication.
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Léger L, Budin-Verneuil A, Cacaci M, Benachour A, Hartke A, Verneuil N. β-Lactam Exposure Triggers Reactive Oxygen Species Formation in Enterococcus faecalis via the Respiratory Chain Component DMK. Cell Rep 2020; 29:2184-2191.e3. [PMID: 31747593 DOI: 10.1016/j.celrep.2019.10.080] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 09/19/2019] [Accepted: 10/18/2019] [Indexed: 01/15/2023] Open
Abstract
Whereas the primary actions of β-lactams are well characterized, their downstream effects are less well understood. Although their targets are extracellular, β-lactams stimulate respiration in Escherichia coli leading to increased intracellular accumulation of reactive oxygen species (ROS). Here, we show that β-lactams over a large concentration range trigger a strong increase in ROS production in Enterococcus faecalis under aerobic, but not anaerobic, conditions. Both amoxicillin, to which the bacterium is susceptible, and cefotaxime, to which E. faecalis is resistant, triggers this response. This stimulation of ROS formation depends mainly on demethylmenaquinone (DMK), a component of the E. faecalis respiratory chain, but in contrast to E. coli is observed only in the absence of respiration. Our results suggest that in E. faecalis, β-lactams increase electron flux through the respiratory chain, thereby stimulating the auto-oxidation of reduced DMK in the absence of respiration, which triggers increased extracellular ROS production.
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Affiliation(s)
- Loïc Léger
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
| | | | - Margherita Cacaci
- Università Cattolica del Sacro Cuore, Instituto di Microbiologia, Rome, Italy
| | - Abdellah Benachour
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
| | - Axel Hartke
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France.
| | - Nicolas Verneuil
- UR Risques Microbiens, Normandie Univ, UNICAEN, U2RM, 14000 Caen, France
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16
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Li J, Wang J, Liu W, Hayashi T, Itoh K, Onodera S, Ikejima T. Metformin protects Escherichia coli from bleomycin-induced bactericide via enhanced generation of hydrogen peroxide. Free Radic Res 2020; 54:64-75. [PMID: 31905044 DOI: 10.1080/10715762.2019.1703968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Bleomycin is a glycopeptide antibiotic that is widely employed in the therapy of a range of lymphomas and germ cell tumours. But the therapeutic efficacy of bleomycin is limited by development of lung fibrosis. The cytotoxicity of bleomycin is mostly ascribed to mitochondrial DNA (mtDNA) damage, while a protective effect of metformin against bleomycin-induced lung fibrosis results from the inhibition of mitochondrial complex I. Since mitochondria and bacteria have certain similarities in structure and function, we used Escherichia coli for simplification in the present work to investigate the relationship between metformin and bleomycin with apparently opposite effects on mitochondrial DNA damage. Bleomycin lethality to E. coli was ameliorated by metformin treatment accompanying further increase of the level of reactive oxygen species. Catalase but not superoxide dismutases attenuated the protective effect of metformin. Meanwhile, treatment with hydrogen peroxide enhanced the protection, indicating that metformin may protect E. coli from bleomycin-induced bactericide via enhanced generation of hydrogen peroxide. Moreover, silibinin, a hepatoprotective polyphenolic flavonoid attenuates the cytotoxicity of bleomycin to E. coli via enhanced generation of hydrogen peroxide as well. This bacterial model in place of mitochondria can provide us with easier screening for the molecules with capability of reducing the bleomycin side effect.
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Affiliation(s)
- Jian Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, P. R. China
| | - Jiaojiao Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, P. R. China
| | - Weiwei Liu
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, P. R. China
| | - Toshihiko Hayashi
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, P. R. China.,Department of Chemistry and Life Science, School of Advanced Engineering, Kogakuin University, Hachioji, Japan
| | | | | | - Takashi Ikejima
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, P. R. China.,Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research & Development, Shenyang Pharmaceutical University, Shenyang, P. R. China
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17
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Ni H, Xiong Z, Mohsin A, Guo M, Petkovic H, Chu J, Zhuang Y. Study on a two-component signal transduction system RimA1A2 that negatively regulates oxytetracycline biosynthesis in Streptomyces rimosus M4018. BIORESOUR BIOPROCESS 2019. [DOI: 10.1186/s40643-019-0238-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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18
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Role of epaQ, a Previously Uncharacterized Enterococcus faecalis Gene, in Biofilm Development and Antimicrobial Resistance. J Bacteriol 2019; 201:JB.00078-19. [PMID: 30910809 DOI: 10.1128/jb.00078-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022] Open
Abstract
Enterococcus faecalis is a commensal of the human gastrointestinal tract; it is also an opportunistic pathogen and one of the leading causes of hospital-acquired infections. E. faecalis produces biofilms that are highly resistant to antibiotics, and it has been previously reported that certain genes of the epa operon contribute to biofilm-associated antibiotic resistance. Despite several studies examining the epa operon, many gene products of this operon remain annotated as hypothetical proteins. Here, we further explore the epa operon; we identified epaQ, currently annotated as encoding a hypothetical membrane protein, as being important for biofilm formation in the presence of the antibiotic daptomycin. Mutants with disruptions of epaQ were more susceptible to daptomycin relative to the wild type, suggesting its importance in biofilm-associated antibiotic resistance. Furthermore, the ΔepaQ mutant exhibited an altered biofilm architectural arrangement and formed small aggregates in liquid cultures. Our cumulative data show that epa mutations result in altered polysaccharide content, increased cell surface hydrophobicity, and decreased membrane potential. Surprisingly, several epa mutations significantly increased resistance to the antibiotic ceftriaxone, indicating that the way in which the epa operon impacts antibiotic resistance is antibiotic dependent. These results further define the key role of epa in antibiotic resistance in biofilms and in biofilm architecture.IMPORTANCE E. faecalis is a common cause of nosocomial infection, has a high level of antibiotic resistance, and forms robust biofilms. Biofilm formation is associated with increased antibiotic resistance. Therefore, a thorough understanding of biofilm-associated antibiotic resistance is important for combating resistance. Several genes from the epa operon have previously been implicated in biofilm-associated antibiotic resistance, pathogenesis, and competitive fitness in the GI tract, but most genes in this locus remain uncharacterized. Here, we examine epaQ, which has not been characterized functionally. We show that the ΔepaQ mutant exhibits reduced biofilm formation in the presence of daptomycin, altered biofilm architecture, and increased resistance to ceftriaxone, further expanding our understanding of the contribution of this operon to intrinsic enterococcal antibiotic resistance and biofilm growth.
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19
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Hyoju SK, Zaborin A, Keskey R, Sharma A, Arnold W, van den Berg F, Kim SM, Gottel N, Bethel C, Charnot-Katsikas A, Jianxin P, Adriaansens C, Papazian E, Gilbert JA, Zaborina O, Alverdy JC. Mice Fed an Obesogenic Western Diet, Administered Antibiotics, and Subjected to a Sterile Surgical Procedure Develop Lethal Septicemia with Multidrug-Resistant Pathobionts. mBio 2019; 10:e00903-19. [PMID: 31363025 PMCID: PMC6667615 DOI: 10.1128/mbio.00903-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/08/2019] [Indexed: 12/22/2022] Open
Abstract
Despite antibiotics and sterile technique, postoperative infections remain a real and present danger to patients. Recent estimates suggest that 50% of the pathogens associated with postoperative infections have become resistant to the standard antibiotics used for prophylaxis. Risk factors identified in such cases include obesity and antibiotic exposure. To study the combined effect of obesity and antibiotic exposure on postoperative infection, mice were allowed to gain weight on an obesogenic Western-type diet (WD), administered antibiotics and then subjected to an otherwise recoverable sterile surgical injury (30% hepatectomy). The feeding of a WD alone resulted in a major imbalance of the cecal microbiota characterized by a decrease in diversity, loss of Bacteroidetes, a bloom in Proteobacteria, and the emergence of antibiotic-resistant organisms among the cecal microbiota. When WD-fed mice were administered antibiotics and subjected to 30% liver resection, lethal sepsis, characterized by multiple-organ damage, developed. Notable was the emergence and systemic dissemination of multidrug-resistant (MDR) pathobionts, including carbapenem-resistant, extended-spectrum β-lactamase-producing Serratia marcescens, which expressed a virulent and immunosuppressive phenotype. Analysis of the distribution of exact sequence variants belonging to the genus Serratia suggested that these strains originated from the cecal mucosa. No mortality or MDR pathogens were observed in identically treated mice fed a standard chow diet. Taken together, these results suggest that consumption of a Western diet and exposure to certain antibiotics may predispose to life-threating postoperative infection associated with MDR organisms present among the gut microbiota.IMPORTANCE Obesity remains a prevalent and independent risk factor for life-threatening infection following major surgery. Here, we demonstrate that when mice are fed an obesogenic Western diet (WD), they become susceptible to lethal sepsis with multiple organ damage after exposure to antibiotics and an otherwise-recoverable surgical injury. Analysis of the gut microbiota in this model demonstrates that WD alone leads to loss of Bacteroidetes, a bloom of Proteobacteria, and evidence of antibiotic resistance development even before antibiotics are administered. After antibiotics and surgery, lethal sepsis with organ damage developed in in mice fed a WD with the appearance of multidrug-resistant pathogens in the liver, spleen, and blood. The importance of these findings lies in exposing how the selective pressures of diet, antibiotic exposure, and surgical injury can converge on the microbiome, resulting in lethal sepsis and organ damage without the introduction of an exogenous pathogen.
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Affiliation(s)
- Sanjiv K Hyoju
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Alexander Zaborin
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Robert Keskey
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Anukriti Sharma
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Wyatt Arnold
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Fons van den Berg
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
- Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Sangman M Kim
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Neil Gottel
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Cindy Bethel
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
| | | | - Peng Jianxin
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
- Guangdong Province Hospital of Chinese Medicine, China
| | - Carleen Adriaansens
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
- Department of Surgery, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Emily Papazian
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Jack A Gilbert
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Olga Zaborina
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - John C Alverdy
- Department of Surgery, University of Chicago, Chicago, Illinois, USA
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Adaptation to Adversity: the Intermingling of Stress Tolerance and Pathogenesis in Enterococci. Microbiol Mol Biol Rev 2019; 83:83/3/e00008-19. [PMID: 31315902 DOI: 10.1128/mmbr.00008-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterococcus is a diverse and rugged genus colonizing the gastrointestinal tract of humans and numerous hosts across the animal kingdom. Enterococci are also a leading cause of multidrug-resistant hospital-acquired infections. In each of these settings, enterococci must contend with changing biophysical landscapes and innate immune responses in order to successfully colonize and transit between hosts. Therefore, it appears that the intrinsic durability that evolved to make enterococci optimally competitive in the host gastrointestinal tract also ideally positioned them to persist in hospitals, despite disinfection protocols, and acquire new antibiotic resistances from other microbes. Here, we discuss the molecular mechanisms and regulation employed by enterococci to tolerate diverse stressors and highlight the role of stress tolerance in the biology of this medically relevant genus.
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21
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Ctt1 catalase activity potentiates antifungal azoles in the emerging opportunistic pathogen Saccharomyces cerevisiae. Sci Rep 2019; 9:9185. [PMID: 31235707 PMCID: PMC6591360 DOI: 10.1038/s41598-019-45070-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022] Open
Abstract
Fungi respond to antifungal drugs by increasing their antioxidant stress response. How this impacts antifungal efficacy remains controversial and not well understood. Here we examine the role of catalase activity in the resistance of Saccharomyces cerevisiae to the common antifungals, fluconazole and miconazole, for which we report minimum inhibitory concentrations (MICs) of 104 and 19 μM, respectively. At sub-MIC concentrations, fluconazole and miconazole stimulate catalase activity 2-3-fold but, unexpectedly, deletion of cytosolic catalase (ctt1) makes cells more resistant to these azoles and to clotrimazole, itraconazole and posaconazole. On the other hand, upregulating Ctt1 activity by preconditioning with 0.2 mM H2O2 potentiates miconazole 32-fold and fluconazole 4-fold. Since H2O2 preconditioning does not alter the resistance of ctt1Δ cells, which possess negligible catalase activity, we link azole potentiation with Ctt1 upregulation. In contrast, sod2Δ cells deleted for mitochondrial superoxide dismutase are 4–8-fold more azole sensitive than wild-type cells, revealing that Sod2 activity protects cells against azole toxicity. In fact, the ctt1Δ mutant has double the Sod2 activity of wild-type cells so ctt1 deletion increases azole resistance in part by Sod2 upregulation. Notably, deletion of peroxisomal/mitochondrial cta1 or cytosolic sod1 does not alter fluconazole or miconazole potency.
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Sortase-Dependent Proteins Promote Gastrointestinal Colonization by Enterococci. Infect Immun 2019; 87:IAI.00853-18. [PMID: 30804098 DOI: 10.1128/iai.00853-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/18/2019] [Indexed: 12/19/2022] Open
Abstract
The human gastrointestinal tract (GIT) is inhabited by a dense microbial community of symbionts. Enterococci are among the earliest members of this community and remain core members of the GIT microbiota throughout life. Enterococci have also recently emerged as opportunistic pathogens and major causes of nosocomial infections. Although recognized as a prerequisite for infection, colonization of the GIT by enterococci remains poorly understood. One way that bacteria adapt to dynamic ecosystems like the GIT is through the use of their surface proteins to sense and interact with components of their immediate environment. In Gram-positive bacteria, a subset of surface proteins relies on an enzyme called sortase for covalent attachment to the cell wall. Here, we show that the housekeeping sortase A (SrtA) enzyme promotes intestinal colonization by enterococci. Furthermore, we show that the enzymatic activity of SrtA is key to the ability of Enterococcus faecalis to bind mucin (a major component of the GIT mucus). We also report the GIT colonization phenotypes of E. faecalis mutants lacking selected sortase-dependent proteins (SDPs). Further examination of the mucin binding ability of these mutants suggests that adhesion to mucin contributes to intestinal colonization by E. faecalis.
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23
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Yan Y, Wang Y, Wang W, Zhou S, Wang J, Guo J. Comparison of short-term dosing ferrous ion and nanoscale zero-valent iron for rapid recovery of anammox activity from dissolved oxygen inhibition. WATER RESEARCH 2019; 153:284-294. [PMID: 30735958 DOI: 10.1016/j.watres.2019.01.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/25/2019] [Accepted: 01/27/2019] [Indexed: 06/09/2023]
Abstract
As obligate anaerobes, anammox bacteria are sensitive to oxygen, which might hinder the maximization of anammox activity. However, there are very few effective strategies to rapidly recover anammox activity after its deterioration under exposure of oxygen. In this study, the activity recovery of anammox bacteria encountering dissolved oxygen (DO) exposure (0.2 and 2.0 mg L-1) were compared by three strategies in short-term experiments, nZVI, Fe(II) dosing, and N2 purging. nZVI is more effective in recovering anammox activity with a high DO exposure (2 mg L-1), compared to a low DO exposure (0.2 mg L-1). After inhibiting by 2.0 mg L-1 DO, anammox activity recovery (normalized to the control) was ranked in the order of nZVI (5 mg L-1) addition (63 ± 8.2%) > Fe(II) (5 mg L-1) addition (41 ± 8.0%) >N2 purging (39 ± 4.0%). In contrast to Fe(II) ion additions, the shell structure of nZVI combined with the buffering effect of biomass-extracellular polysaccharide (EPS) prevented the sharp pH variation and excessive dissolved Fe(II)/Fe(III) in solution. Under such circumstances, nZVI addition (5 and 25 mg L-1) increased the intracellular reactive oxygen species (ROS) to a moderate level (<200%), which might be responsible for the better activity recovery of anammox than that of Fe(II) addition and N2 purging. Specifically, 5 mg L-1 nZVI dosage moderately enhanced the intracellular O2- production (∼150% of the control) after scavenging 2.0 mg L-1 DO, and the anammox activity recovered better than that of both 5 and 25 mg L-1 Fe(II) ions additions. However, high dosage nZVI (75 mg L-1) inhibited anammox activity in spite of low or high DO exposure. Our findings elucidate that appropriate amount of nZVI (short-term dosing) can rapidly recover anammox activity when anammox bacteria encountering oxygen exposure accidentally and could be useful in facilitating the robust operation of anammox-based processes.
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Affiliation(s)
- Yuan Yan
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China.
| | - Weigang Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Shuai Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Junjie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Jianhua Guo
- Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD, 4072, Australia
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Dąbrowska M, Komsta Ł, Opoka W, Starek M. Chemometric analysis of chromatographic data in stability investigation of cephalosporins. ACTA CHROMATOGR 2018. [DOI: 10.1556/1326.2017.00341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- M. Dąbrowska
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688 Krakow, Poland
| | - Ł. Komsta
- Department of Medicinal Chemistry, Medical University of Lublin, 4 Jaczewskiego St, 20-090 Lublin, Poland
| | - W. Opoka
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688 Krakow, Poland
| | - M. Starek
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688 Krakow, Poland
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25
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Oladeinde A, Lipp E, Chen CY, Muirhead R, Glenn T, Cook K, Molina M. Transcriptome Changes of Escherichia coli, Enterococcus faecalis, and Escherichia coli O157:H7 Laboratory Strains in Response to Photo-Degraded DOM. Front Microbiol 2018; 9:882. [PMID: 29867797 PMCID: PMC5953345 DOI: 10.3389/fmicb.2018.00882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/17/2018] [Indexed: 11/26/2022] Open
Abstract
In this study, we investigated gene expression changes in three bacterial strains (Escherichia coli C3000, Escherichia coli O157:H7 B6914, and Enterococcus faecalis ATCC 29212), commonly used as indicators of water quality and as control strains in clinical, food, and water microbiology laboratories. Bacterial transcriptome responses from pure cultures were monitored in microcosms containing water amended with manure-derived dissolved organic matter (DOM), previously exposed to simulated sunlight for 12 h. We used RNA sequencing (RNA-seq) and quantitative real-time reverse transcriptase (qRT-PCR) to compare differentially expressed temporal transcripts between bacteria incubated in microcosms containing sunlight irradiated and non-irradiated DOM, for up to 24 h. In addition, we used whole genome sequencing simultaneously with RNA-seq to identify single nucleotide variants (SNV) acquired in bacterial populations during incubation. These results indicate that E. coli and E. faecalis have different mechanisms for removal of reactive oxygen species (ROS) produced from irradiated DOM. They are also able to produce micromolar concentrations of H2O2 from non-irradiated DOM, that should be detrimental to other bacteria present in the environment. Notably, this study provides an assessment of the role of two conjugative plasmids carried by the E. faecalis and highlights the differences in the overall survival dynamics of environmentally-relevant bacteria in the presence of naturally-produced ROS.
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Affiliation(s)
- Adelumola Oladeinde
- National Exposure Research Laboratory, Student Volunteer, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States.,Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Erin Lipp
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Chia-Ying Chen
- National Exposure Research Laboratory, National Research Council Associate, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States
| | | | - Travis Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Kimberly Cook
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, GA, United States
| | - Marirosa Molina
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States
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Doyle LE, Marsili E. Weak electricigens: A new avenue for bioelectrochemical research. BIORESOURCE TECHNOLOGY 2018; 258:354-364. [PMID: 29519634 DOI: 10.1016/j.biortech.2018.02.073] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 05/20/2023]
Abstract
Electroactivity appears to be a phylogenetically diverse trait independent of cell wall classification, with both Gram-negative and Gram-positive electricigens reported. While numerous electricigens have been observed, the majority of research focuses on a select group of highly electroactive species. Under favorable conditions, many microorganisms can be considered electroactive, either through their own mechanisms or exogenously-added mediators, producing a weak current. Such microbes should not be dismissed based on their modest electroactivity. Rather, they may be key to understanding what drives extracellular electron transfer in response to transient limitations of electron acceptor or donor, with implications for the study of pathogens and industrial bioprocesses. Due to their low electroactivity, such populations are difficult to grow in bioelectrochemical systems and characterise with electrochemistry. Here, a critical review of recent research on weak electricigens is provided, with a focus on the methodology and the overall relevance to microbial ecology and bioelectrochemical systems.
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Affiliation(s)
- Lucinda E Doyle
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Enrico Marsili
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore.
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Convergence of PASTA Kinase and Two-Component Signaling in Response to Cell Wall Stress in Enterococcus faecalis. J Bacteriol 2018; 200:JB.00086-18. [PMID: 29632091 DOI: 10.1128/jb.00086-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/03/2018] [Indexed: 12/20/2022] Open
Abstract
Two common signal transduction mechanisms used by bacteria to sense and respond to changing environments are two-component systems (TCSs) and eukaryote-like Ser/Thr kinases and phosphatases (eSTK/Ps). Enterococcus faecalis is a Gram-positive bacterium and a serious opportunistic pathogen that relies on both a TCS and an eSTK/P pathway for intrinsic resistance to cell wall-targeting antibiotics. The TCS consists of a histidine kinase (CroS) and a response regulator (CroR) that become activated upon exposure of cells to cell wall-targeting antibiotics, leading to a modulation of gene expression. The eSTK/P pathway consists of a transmembrane kinase (IreK) and its cognate phosphatase (IreP), which act antagonistically to mediate antibiotic resistance through an unknown mechanism. Because both CroS/R and IreK/P contribute to enterococcal resistance toward cell wall-targeting antibiotics, we hypothesized that these signaling systems are intertwined. To test this hypothesis, we analyzed CroR phosphorylation and CroS/R-dependent gene expression to probe the influence of IreK and IreP on CroS/R signaling. In addition, we analyzed the phosphorylation state of CroS, which revealed the IreK-dependent phosphorylation of a Thr residue important for CroS function. Our results are consistent with a model in which IreK positively influences CroR-dependent gene expression through the phosphorylation of CroS to promote antimicrobial resistance in E. faecalis IMPORTANCE Two-component signaling systems (TCSs) and eukaryote-like Ser/Thr kinases (eSTKs) are used by bacteria to sense and adapt to changing environments. Understanding how these pathways are regulated to promote bacterial survival is critical for a more complete understanding of bacterial stress responses and physiology. The opportunistic pathogen Enterococcus faecalis relies on both a TCS (CroS/R) and an eSTK (IreK) for intrinsic resistance to cell wall-targeting antibiotics. We probed the relationship between CroS/R and IreK, revealing the convergence of IreK and the sensor kinase CroS to enhance signaling through CroS/R and increase antimicrobial resistance in E. faecalis This newly described example of eSTK/TCS convergence adds to our understanding of the signaling networks mediating antimicrobial resistance in E. faecalis.
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Cai JY, Wang YY, Ma K, Hou YN, Yao GD, Hayashi T, Itoh K, Tashiro SI, Onodera S, Ikejima T. Salicylate induces reactive oxygen species and reduces ultraviolet C susceptibility in Staphylococcus aureus. FEMS Microbiol Lett 2018; 365:4931717. [PMID: 29546276 DOI: 10.1093/femsle/fny056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 03/06/2018] [Indexed: 11/13/2022] Open
Abstract
This study demonstrates that growth of Staphylococcus aureus in the presence of salicylate reduces ultraviolet C (UVC)-induced cell death and increases the generation of reactive oxygen species (ROS). In addition, compounds that scavenge ROS (N-acetylcysteine, glutathione, catalase and superoxide dismutase) reverse the increased UVC survival induced by growth in the presence of salicylate, while ROS donors (tert-butylhydroperoxide, H2O2 and NaClO) enhance survival of salicylate challenged cultures. Collectively, these findings suggest that ROS production induced by growth in the presence of salicylate protects S. aureus from UVC-induced cell death.
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Affiliation(s)
- Jia-Yi Cai
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yuan-Yuan Wang
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China.,Department of Drug Discover and Development, Shanghai FrontHealth Pharmaceutical Technology Company, Shanghai 201203, China
| | - Kai Ma
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yong-Na Hou
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Guo-Dong Yao
- School of Traditional Chinese Materia Medica, Key Laboratory of Structure-Based Drug Design & Discovery (Ministry of Education), Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Toshihiko Hayashi
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Kikuji Itoh
- Biochemical Center, Japan SLC, Inc., Shizuoka 431-1103, Japan
| | - Shin-Ichi Tashiro
- Department of Medical Education & Primary Care, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Satoshi Onodera
- Department of Clinical and Pharmaceutical Sciences, Showa Pharmaceutical University, Tokyo 194-8543, Japan
| | - Takashi Ikejima
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
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Muller C, Massier S, Le Breton Y, Rincé A. The role of the CroR response regulator in resistance of Enterococcus faecalis to D-cycloserine is defined using an inducible receiver domain. Mol Microbiol 2017; 107:416-427. [PMID: 29205552 DOI: 10.1111/mmi.13891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/28/2017] [Accepted: 12/01/2017] [Indexed: 11/28/2022]
Abstract
Enterococcus faecalis is an opportunistic multidrug-resistant human pathogen causing severe nosocomial infections. Previous investigations revealed that the CroRS two-component regulatory pathway likely displays a pleiotropic role in E. faecalis, involved in virulence, macrophage survival, oxidative stress response as well as antibiotic resistance. Therefore, CroRS represents an attractive potential new target for antibiotherapy. In this report, we further explored CroRS cellular functions by characterizing the CroR regulon: the 'domain swapping' method was applied and a CroR chimera protein was generated by fusing the receiver domain from NisR to the output domain from CroR. After demonstrating that the chimera CroR complements a croR gene deletion in E. faecalis (stress response, virulence), we conducted a global gene expression analysis using RNA-Seq and identified 50 potential CroR targets involved in multiple cellular functions such as cell envelope homeostasis, substrate transport, cell metabolism, gene expression regulation, stress response, virulence and antibiotic resistance. For validation, CroR direct binding to several candidate targets was demonstrated by EMSA. Further, this work identified alr, the gene encoding the alanine racemase enzyme involved in E. faecalis resistance to D-cycloserine, a promising antimicrobial drug to treat enterococcal infections, as a member of the CroR regulon.
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Affiliation(s)
- Cécile Muller
- Normandie Univ, UNICAEN, U2RM - Unité de Recherche Risques Microbiens, Caen, France
| | - Sébastien Massier
- Normandie Univ, UNICAEN, U2RM - Unité de Recherche Risques Microbiens, Caen, France
| | - Yoann Le Breton
- Normandie Univ, UNICAEN, U2RM - Unité de Recherche Risques Microbiens, Caen, France
| | - Alain Rincé
- Normandie Univ, UNICAEN, U2RM - Unité de Recherche Risques Microbiens, Caen, France
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Modulators of Enterococcus faecalis Cell Envelope Integrity and Antimicrobial Resistance Influence Stable Colonization of the Mammalian Gastrointestinal Tract. Infect Immun 2017; 86:IAI.00381-17. [PMID: 29038125 DOI: 10.1128/iai.00381-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/09/2017] [Indexed: 02/07/2023] Open
Abstract
The Gram-positive bacterium Enterococcus faecalis is both a colonizer of the gastrointestinal tract (GIT) and an agent of serious nosocomial infections. Although it is typically required for pathogenesis, GIT colonization by E. faecalis is poorly understood. E. faecalis tolerates high concentrations of GIT antimicrobials, like cholate and lysozyme, leading us to hypothesize that resistance to intestinal antimicrobials is essential for long-term GIT colonization. Analyses of E. faecalis mutants exhibiting defects in antimicrobial resistance revealed that IreK, a determinant of envelope integrity and antimicrobial resistance, is required for long-term GIT colonization. IreK is a member of the PASTA kinase protein family, bacterial transmembrane signaling proteins implicated in the regulation of cell wall homeostasis. Among several determinants of cholate and lysozyme resistance in E. faecalis, IreK was the only one found to be required for intestinal colonization, emphasizing the importance of this protein to enterococcal adaptation to the GIT. By studying ΔireK suppressor mutants that recovered the ability to colonize the GIT, we identified two conserved enterococcal proteins (OG1RF_11271 and OG1RF_11272) that function antagonistically to IreK and interfere with cell envelope integrity, antimicrobial resistance, and GIT colonization. Our data suggest that IreK, through its kinase activity, inhibits the actions of these proteins. IreK, OG1RF_11271, and OG1RF_11272 are found in all enterococci, suggesting that their effect on GIT colonization is universal across enterococci. Thus, we have defined conserved genes in the enterococcal core genome that influence GIT colonization through their effect on enterococcal envelope integrity and antimicrobial resistance.
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Djorić D, Kristich CJ. Extracellular SalB Contributes to Intrinsic Cephalosporin Resistance and Cell Envelope Integrity in Enterococcus faecalis. J Bacteriol 2017; 199:e00392-17. [PMID: 28874409 PMCID: PMC5686589 DOI: 10.1128/jb.00392-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/30/2017] [Indexed: 11/20/2022] Open
Abstract
Enterococci are major causes of hospital-acquired infections. Intrinsic resistance to cephalosporins is a universal trait among clinically relevant enterococci. Cephalosporin resistance enables enterococci to proliferate to high densities in the intestines of patients undergoing cephalosporin treatment, a precursor to the emergence of infection. However, the genetic and biochemical mechanisms of intrinsic cephalosporin resistance in enterococci are not well understood. A two-component signal transduction system, CroR/S, is required for cephalosporin resistance in enterococci. Although the CroR/S regulon is not well defined, one gene reported to be CroR dependent in Enterococcus faecalis JH2-2 encodes an extracellular putative peptidoglycan hydrolase, SalB. To test the hypothesis that SalB is responsible for CroR-dependent cephalosporin resistance, we examined ΔsalB mutants in multiple genetic lineages of E. faecalis, revealing that SalB is required not only for intrinsic cephalosporin resistance but also for maintenance of cell envelope integrity in the absence of antibiotic stress. The N-terminal signal sequence is necessary for SalB secretion, and secretion is required for SalB to promote cephalosporin resistance. Functional dissection revealed that the C-terminal SCP domain of SalB is essential for biological activity and identified three residues within the SCP domain that are required for the stability and function of SalB. Additionally, we found that in contrast to what is seen in E. faecalis JH2-2, SalB is not regulated by the CroR/S two-component system in E. faecalis OG1, suggesting diversity in the CroR/S regulon among distinct lineages of E. faecalis IMPORTANCE Resistance to cephalosporins is universal among clinically relevant enterococci, enabling enterococcal proliferation to high densities in the intestines of patients undergoing cephalosporin treatment, a precursor to the emergence of infection. Disabling cephalosporin resistance could therefore reduce the incidence of enterococcal infections. However, the genetic and biochemical mechanisms of cephalosporin resistance are not well understood. The significance of this work is the identification of a novel extracellular factor (SalB) that promotes cephalosporin resistance in E. faecalis, which could potentially serve as a target for therapeutics that impair enterococcal cephalosporin resistance. Additionally, our work highlights the importance of the C-terminal SCP domain of SalB, including several conserved residues within the SCP domain, for the ability of SalB to promote cephalosporin resistance.
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Affiliation(s)
- Dušanka Djorić
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Growth- and Stress-Induced PASTA Kinase Phosphorylation in Enterococcus faecalis. J Bacteriol 2017; 199:JB.00363-17. [PMID: 28808126 DOI: 10.1128/jb.00363-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/04/2017] [Indexed: 12/22/2022] Open
Abstract
Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes Such PASTA kinases regulate critical processes, including antibiotic resistance, cell division, toxin production, and virulence, and are essential for viability in certain organisms. Based on in vitro studies with purified extracellular and intracellular fragments of PASTA kinases, a model for signaling has been proposed, in which the extracellular PASTA domains bind currently undefined ligands (typically thought to be peptidoglycan, or fragments thereof) to drive kinase dimerization, which leads to enhanced kinase autophosphorylation and enhanced phosphorylation of substrates. However, this model has not been rigorously tested in vivoEnterococcus faecalis is a Gram-positive intestinal commensal and major antibiotic-resistant opportunistic pathogen. In E. faecalis, the PASTA kinase IreK drives intrinsic resistance to cell wall-active antimicrobials, suggesting that such antimicrobials may trigger IreK signaling. Here we show that IreK responds to cell wall stress in vivo by enhancing its phosphorylation and that of a downstream substrate. This response requires both the extracellular PASTA domains and specific phosphorylatable residues in the kinase domain. Thus, our results provide in vivo evidence, with an intact full-length PASTA kinase in its native physiological environment, that supports the prevailing model of PASTA kinase signaling. In addition, we show that IreK responds to a signal associated with growth and/or cell division, in the absence of cell wall-active antimicrobials. Surprisingly, the ability of IreK to respond to growth and/or division does not require the extracellular PASTA domains, suggesting that IreK monitors multiple parameters for sensory input in vivoIMPORTANCE Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes and regulate critical processes. The prevailing model for signaling by PASTA kinases proposes that the extracellular PASTA domains bind ligands to drive kinase dimerization, enhanced autophosphorylation, and enhanced phosphorylation of substrates. However, this model has not been rigorously tested in vivo We show that the PASTA kinase IreK of Enterococcus faecalis responds to cell wall stress in vivo by enhancing its phosphorylation and that of a downstream substrate. This response requires the PASTA domains and phosphorylatable residues in the kinase domain. Thus, our results provide in vivo evidence, with an intact full-length PASTA kinase in its native physiological environment, that supports the prevailing model of PASTA kinase signaling.
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Cai JY, Wang YY, Ma K, Hou YN, Li J, Yao GD, Liu WW, Otkur W, Hayashi T, Itoh K, Tashiro SI, Ikejima T. Silibinin protects Staphylococcus aureus from UVC-induced bactericide via enhanced generation of reactive oxygen species. RSC Adv 2017. [DOI: 10.1039/c7ra03981f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
ROS produced by silibinin suppresses UVC-inducedStaphylococcus aureuscell death.
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Bhatty M, Camacho MI, Gonzalez-Rivera C, Frank KL, Dale JL, Manias DA, Dunny GM, Christie PJ. PrgU: a suppressor of sex pheromone toxicity in Enterococcus faecalis. Mol Microbiol 2016; 103:398-412. [PMID: 27785854 DOI: 10.1111/mmi.13563] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Upon sensing of the peptide pheromone cCF10, Enterococcus faecalis cells carrying pCF10 produce three surface adhesins (PrgA, PrgB or Aggregation Substance, PrgC) and the Prg/Pcf type IV secretion system and, in turn, conjugatively transfer the plasmid at high frequencies to recipient cells. Here, we report that cCF10 induction is highly toxic to cells sustaining a deletion of prgU, a small orf located immediately downstream of prgB on pCF10. Upon pheromone exposure, these cells overproduce the Prg adhesins and display impaired envelope integrity, as evidenced by antibiotic susceptibility, misplaced division septa and cell lysis. Compensatory mutations in regulatory loci controlling expression of pCF10-encoded prg/pcf genes, or constitutive PrgU overproduction, block production of the Prg adhesins and render cells insensitive to pheromone. Cells engineered to overproduce PrgB, even independently of other pCF10-encoded proteins, have severely compromised cell envelopes and strong growth defects. PrgU has an RNA-binding fold, and prgB-prgU gene pairs are widely distributed among E. faecalis isolates and other enterococcal and staphylococcal species. Together, our findings support a model in which PrgU proteins represent a novel class of RNA-binding regulators that act to mitigate toxicity accompanying overproduction of PrgB-like adhesins in E. faecalis and other clinically-important Gram-positive species.
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Affiliation(s)
- Minny Bhatty
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Martha I Camacho
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Christian Gonzalez-Rivera
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Kristi L Frank
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Jennifer L Dale
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Dawn A Manias
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
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D'Ercole S, Spoto G, Trentini P, Tripodi D, Petrini M. In vitro inactivation of Enterococcus faecalis with a led device. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 160:172-7. [DOI: 10.1016/j.jphotobiol.2016.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 03/29/2016] [Accepted: 04/06/2016] [Indexed: 12/13/2022]
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Hoff JS, Kristich CJ. Thymidylate Limitation Potentiates Cephalosporin Activity toward Enterococci via an Exopolysaccharide-Based Mechanism. ACS Chem Biol 2016; 11:1561-8. [PMID: 27008338 DOI: 10.1021/acschembio.5b01041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Multidrug resistant enterococci are major causes of nosocomial infections. Prior therapy with cephalosporins increases the risk of developing an enterococcal infection due to the intrinsic resistance of enterococci to these antibiotics. While progress has been made toward understanding the genetic and biochemical mechanisms of cephalosporin resistance, available data indicate that as-yet-unidentified resistance factors must exist. Here, we describe results of a screen to identify small molecules capable of sensitizing enterococci to broad-spectrum cephalosporins. We found that both Enterococcus faecalis and Enterococcus faecium were sensitized to broad and expanded-spectrum cephalosporins when thymidylate production was impaired, whether by direct inhibition of thymidylate synthase, or by limiting production of cofactors required for its activity. Cephalosporin potentiation is the result of altered exopolysaccharide production due to reduced dTDP-glucose synthesis. Hence, exopolysaccharide production is a previously undescribed contributor to the intrinsic cephalosporin resistance of enterococci and serves as a new target for antienterococcal therapeutics.
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Affiliation(s)
- Jessica S. Hoff
- Department of Microbiology
and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Christopher J. Kristich
- Department of Microbiology
and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Fisher JF, Mobashery S. β-Lactam Resistance Mechanisms: Gram-Positive Bacteria and Mycobacterium tuberculosis. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025221. [PMID: 27091943 DOI: 10.1101/cshperspect.a025221] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The value of the β-lactam antibiotics for the control of bacterial infection has eroded with time. Three Gram-positive human pathogens that were once routinely susceptible to β-lactam chemotherapy-Streptococcus pneumoniae, Enterococcus faecium, and Staphylococcus aureus-now are not. Although a fourth bacterium, the acid-fast (but not Gram-positive-staining) Mycobacterium tuberculosis, has intrinsic resistance to earlier β-lactams, the emergence of strains of this bacterium resistant to virtually all other antibiotics has compelled the evaluation of newer β-lactam combinations as possible contributors to the multidrug chemotherapy required to control tubercular infection. The emerging molecular-level understanding of these resistance mechanisms used by these four bacteria provides the conceptual framework for bringing forward new β-lactams, and new β-lactam strategies, for the future control of their infections.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
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Functional Dissection of the CroRS Two-Component System Required for Resistance to Cell Wall Stressors in Enterococcus faecalis. J Bacteriol 2016; 198:1326-36. [PMID: 26883822 DOI: 10.1128/jb.00995-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/05/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Bacteria use two-component signal transduction systems (TCSs) to sense and respond to environmental changes via a conserved phosphorelay between a sensor histidine kinase and its cognate response regulator. The opportunistic pathogen Enterococcus faecalis utilizes a TCS comprised of the histidine kinase CroS and the response regulator CroR to mediate resistance to cell wall stresses such as cephalosporin antibiotics, but the molecular details by which CroRS promotes cephalosporin resistance have not been elucidated. Here, we analyzed mutants of E. faecalis carrying substitutions in CroR and CroS to demonstrate that phosphorylated CroR drives resistance to cephalosporins, and that CroS exhibits kinase and phosphatase activities to control the level of CroR phosphorylation in vivo. Deletion of croS in various lineages of E. faecalis revealed a CroS-independent mechanism for CroR phosphorylation and led to the identification of a noncognate histidine kinase capable of influencing CroR (encoded by OG1RF_12162; here called cisS). Further analysis of this TCS network revealed that both systems respond to cell wall stress. IMPORTANCE TCSs allow bacteria to sense and respond to many different environmental conditions. The opportunistic pathogen Enterococcus faecalis utilizes the CroRS TCS to mediate resistance to cell wall stresses, including clinically relevant antibiotics such as cephalosporins and glycopeptides. In this study, we use genetic and biochemical means to investigate the relationship between CroRS signaling and cephalosporin resistance in E. faecalis cells. Through this, we uncovered a signaling network formed between the CroRS TCS and a previously uncharacterized TCS that also responds to cell wall stress. This study provides mechanistic insights into CroRS signaling and cephalosporin resistance in E. faecalis.
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Suraju MO, Lalinde-Barnes S, Sanamvenkata S, Esmaeili M, Shishodia S, Rosenzweig JA. The effects of indoor and outdoor dust exposure on the growth, sensitivity to oxidative-stress, and biofilm production of three opportunistic bacterial pathogens. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 538:949-958. [PMID: 26363607 DOI: 10.1016/j.scitotenv.2015.08.063] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/09/2015] [Accepted: 08/12/2015] [Indexed: 06/05/2023]
Abstract
Within the last decade, many studies have highlighted the radical changes in the components of indoor and outdoor dust. For example, agents like automobile emitted platinum group elements and different kinds of organic phthalates and esters have been reported to be accumulating in the biosphere. Humans consistently face dermal, respiratory, and dietary exposures to these particles while indoors and outdoors. In fact, dust particulate matter has been associated with close to 500,000 deaths per year in Europe and about 200,000 deaths per year in the United States. To date, there has been limited examination of the physiological impact of indoor and outdoor dust exposure on normal flora microbes. In this study, the effect of indoor- and outdoor-dust exposure on three opportunistic bacterial species (Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa) was assessed. Specifically, bacterial growth, oxidative stress resistance, and biofilm production were measured following indoor- and outdoor-dust exposures. Studies were conducted in nutritionally-rich and -poor environments typically encountered by bacteria. Surprisingly, indoor-dust (200μg/mL), enhanced the growth of all three bacterial species in nutrient-poor conditions, but slowed growth in nutrient-rich conditions. In nutrient-rich medium, 100μg/mL exposure of either indoor- or outdoor-dust resulted in significantly reduced oxidative stress resistance in E. coli. Most interestingly, dust (indoor and outdoor), either in nutrient-rich or -poor conditions, significantly increased biofilm production in all three bacterial species. These data suggest that indoor and outdoor dust, can modify opportunistic bacteria through altering growth, sensitivity to oxidative stress, and their virulence potential through enhanced biofilm formation.
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Affiliation(s)
- Mohammed O Suraju
- Department of Biology, Texas Southern University, 3100, Cleburne St, Houston, TX 77099, United States
| | - Sloan Lalinde-Barnes
- DeBakey High School for Health Professions, 3100 Shenandoah St, Houston, TX 77021, United States
| | - Sachindra Sanamvenkata
- DeBakey High School for Health Professions, 3100 Shenandoah St, Houston, TX 77021, United States
| | - Mahsa Esmaeili
- Department of Environmental and Interdisciplinary Sciences, Texas Southern University, Houston, TX 77099, United States
| | - Shishir Shishodia
- Department of Biology, Texas Southern University, 3100, Cleburne St, Houston, TX 77099, United States
| | - Jason A Rosenzweig
- Department of Biology, Texas Southern University, 3100, Cleburne St, Houston, TX 77099, United States; Department of Environmental and Interdisciplinary Sciences, Texas Southern University, Houston, TX 77099, United States.
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Dale JL, Cagnazzo J, Phan CQ, Barnes AMT, Dunny GM. Multiple roles for Enterococcus faecalis glycosyltransferases in biofilm-associated antibiotic resistance, cell envelope integrity, and conjugative transfer. Antimicrob Agents Chemother 2015; 59:4094-105. [PMID: 25918141 PMCID: PMC4468649 DOI: 10.1128/aac.00344-15] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/21/2015] [Indexed: 12/31/2022] Open
Abstract
The emergence of multidrug-resistant bacteria and the limited availability of new antibiotics are of increasing clinical concern. A compounding factor is the ability of microorganisms to form biofilms (communities of cells encased in a protective extracellular matrix) that are intrinsically resistant to antibiotics. Enterococcus faecalis is an opportunistic pathogen that readily forms biofilms and also has the propensity to acquire resistance determinants via horizontal gene transfer. There is intense interest in the genetic basis for intrinsic and acquired antibiotic resistance in E. faecalis, since clinical isolates exhibiting resistance to multiple antibiotics are not uncommon. We performed a genetic screen using a library of transposon (Tn) mutants to identify E. faecalis biofilm-associated antibiotic resistance determinants. Five Tn mutants formed wild-type biofilms in the absence of antibiotics but produced decreased biofilm biomass in the presence of antibiotic concentrations that were subinhibitory to the parent strain. Genetic determinants responsible for biofilm-associated antibiotic resistance include components of the quorum-sensing system (fsrA, fsrC, and gelE) and two glycosyltransferase (GTF) genes (epaI and epaOX). We also found that the GTFs play additional roles in E. faecalis resistance to detergent and bile salts, maintenance of cell envelope integrity, determination of cell shape, polysaccharide composition, and conjugative transfer of the pheromone-inducible plasmid pCF10. The epaOX gene is located in a variable extended region of the enterococcal polysaccharide antigen (epa) locus. These data illustrate the importance of GTFs in E. faecalis adaptation to diverse growth conditions and suggest new targets for antimicrobial design.
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Affiliation(s)
- Jennifer L Dale
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Julian Cagnazzo
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Chi Q Phan
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Aaron M T Barnes
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Gary M Dunny
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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