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Adams JME, Moulding PB, El-Halfawy OM. Polyamine-Mediated Sensitization of Klebsiella pneumoniae to Macrolides through a Dual Mode of Action. ACS Infect Dis 2024; 10:2183-2195. [PMID: 38695481 DOI: 10.1021/acsinfecdis.4c00157] [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] [Indexed: 06/15/2024]
Abstract
Chemicals bacteria encounter at the infection site could shape their stress and antibiotic responses; such effects are typically undetected under standard lab conditions. Polyamines are small molecules typically overproduced by the host during infection and have been shown to alter bacterial stress responses. We sought to determine the effect of polyamines on the antibiotic response of Klebsiella pneumoniae, a Gram-negative priority pathogen. Interestingly, putrescine and other natural polyamines sensitized K. pneumoniae to azithromycin, a macrolide protein translation inhibitor typically used for Gram-positive bacteria. This synergy was further potentiated in the physiological buffer, bicarbonate. Chemical genomic screens suggested a dual mechanism, whereby putrescine acts at the membrane and ribosome levels. Putrescine permeabilized the outer membrane of K. pneumoniae (NPN and β-lactamase assays) and the inner membrane (Escherichia coli β-galactosidase assays). Chemically and genetically perturbing membranes led to a loss of putrescine-azithromycin synergy. Putrescine also inhibited protein synthesis in an E. coli-derived cell-free protein expression assay simultaneously monitoring transcription and translation. Profiling the putrescine-azithromycin synergy against a combinatorial array of antibiotics targeting various ribosomal sites suggested that putrescine acts as tetracyclines targeting the 30S ribosomal acceptor site. Next, exploiting the natural polyamine-azithromycin synergy, we screened a polyamine analogue library for azithromycin adjuvants, discovering four azithromycin synergists with activity starting from the low micromolar range and mechanisms similar to putrescine. This work sheds light on the bacterial antibiotic responses under conditions more reflective of those at the infection site and provides a new strategy to extend the macrolide spectrum to drug-resistant K. pneumoniae.
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Affiliation(s)
- Joshua M E Adams
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Peri B Moulding
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Omar M El-Halfawy
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt
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2
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García-Romero I, Srivastava M, Monjarás-Feria J, Korankye SO, MacDonald L, Scott NE, Valvano MA. Drug efflux and lipid A modification by 4-L-aminoarabinose are key mechanisms of polymyxin B resistance in the sepsis pathogen Enterobacter bugandensis. J Glob Antimicrob Resist 2024; 37:108-121. [PMID: 38552872 DOI: 10.1016/j.jgar.2024.03.012] [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: 12/16/2023] [Revised: 02/27/2024] [Accepted: 03/14/2024] [Indexed: 04/26/2024] Open
Abstract
OBJECTIVES A concern with the ESKAPE pathogen, Enterobacter bugandensis, and other species of the Enterobacter cloacae complex, is the frequent appearance of multidrug resistance against last-resort antibiotics, such as polymyxins. METHODS Here, we investigated the responses to polymyxin B (PMB) in two PMB-resistant E. bugandensis clinical isolates by global transcriptomics and deletion mutagenesis. RESULTS In both isolates, the genes of the CrrAB-regulated operon, including crrC and kexD, displayed the highest levels of upregulation in response to PMB. ∆crrC and ∆kexD mutants became highly susceptible to PMB and lost the heteroresistant phenotype. Conversely, heterologous expression of CrrC and KexD proteins increased PMB resistance in a sensitive Enterobacter ludwigii clinical isolate and in the Escherichia coli K12 strain, W3110. The efflux pump, AcrABTolC, and the two component regulators, PhoPQ and CrrAB, also contributed to PMB resistance and heteroresistance. Additionally, the lipid A modification with 4-L-aminoarabinose (L-Ara4N), mediated by the arnBCADTEF operon, was critical to determine PMB resistance. Biochemical experiments, supported by mass spectrometry and structural modelling, indicated that CrrC is an inner membrane protein that interacts with the membrane domain of the KexD pump. Similar interactions were modeled for AcrB and AcrD efflux pumps. CONCLUSION Our results support a model where drug efflux potentiated by CrrC interaction with membrane domains of major efflux pumps combined with resistance to PMB entry by the L-Ara4N lipid A modification, under the control of PhoPQ and CrrAB, confers the bacterium high-level resistance and heteroresistance to PMB.
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Affiliation(s)
- Inmaculada García-Romero
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, United Kingdom; Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide, Sevilla, Spain
| | - Mugdha Srivastava
- Functional Genomics & Systems Biology Group, Department of Bioinformatics, Biocenter, Am Hubland, University of Wuerzburg, Wuerzburg, Germany; Core Unit Systems Medicine, University of Wuerzburg, Wuerzburg, Germany
| | - Julia Monjarás-Feria
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Samuel O Korankye
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Lewis MacDonald
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, United Kingdom
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, United Kingdom.
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3
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Naik H, Maiti S, Amaresan N. Microbial volatile compounds (MVCs): an eco-friendly tool to manage abiotic stress in plants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:91746-91760. [PMID: 37531051 DOI: 10.1007/s11356-023-29010-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/23/2023] [Indexed: 08/03/2023]
Abstract
Microbial volatile compounds (MVCs) are produced during the metabolism of microorganisms, are widely distributed in nature, and have significant applications in various fields. To date, several MVCs have been identified. Microbial groups such as bacteria and fungi release many organic and inorganic volatile compounds. They are typically small odorous compounds with low molecular masses, low boiling points, and lipophilic moieties with high vapor pressures. The physicochemical properties of MVCs help them to diffuse more readily in nature and allow dispersal to a more profound distance than other microbial non-volatile metabolites. In natural environments, plants communicate with several microorganisms and respond differently to MVCs. Here, we review the following points: (1) MVCs produced by various microbes including bacteria, fungi, viruses, yeasts, and algae; (2) How MVCs are effective, simple, efficient, and can modulate plant growth and developmental processes; and (3) how MVCs improve photosynthesis and increase plant resistance to various abiotic stressors.
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Affiliation(s)
- Hetvi Naik
- C. G. Bhakta Institute of Biotechnology, Uka Tarsadia University, Maliba Campus, Bardoli, Surat, Gujarat, 394 350, India
| | - Saborni Maiti
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Natarajan Amaresan
- C. G. Bhakta Institute of Biotechnology, Uka Tarsadia University, Maliba Campus, Bardoli, Surat, Gujarat, 394 350, India.
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4
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Bhagwat AC, Saroj SD. Polyamine as a microenvironment factor in resistance to antibiotics. Crit Rev Microbiol 2023:1-10. [PMID: 37339480 DOI: 10.1080/1040841x.2023.2223277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/30/2023] [Accepted: 06/05/2023] [Indexed: 06/22/2023]
Abstract
One of the main issues in modern medicine is the decrease in the efficacy of antibiotic therapy against resistant microorganisms. The advent of antimicrobial resistance has added significantly to the impact of infectious diseases, in number of infections, as well as added healthcare costs. The development of antibiotic tolerance and resistance is influenced by a variety of environmental variables, and it is important to identify these environmental factors as part of any strategy for combating antibiotic resistance. The review aims to emphasize that biogenic polyamines are one of such environmental cues that impacts the antibiotic resistance in bacteria. The biogenic polyamines can help bacteria acquire resistance to antibiotics either by regulating the level of number of porin channels in the outer membrane, by modifying the outer membrane liposaccharides or by protecting macromolecule from antibiotic stress. Thus, understanding the way polyamines function in bacteria can thus be beneficial while designing the drugs to combat diseases.
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Affiliation(s)
- Amrita C Bhagwat
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, Maharashtra, India
| | - Sunil D Saroj
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, Maharashtra, India
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5
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Polymyxin Resistance and Heteroresistance Are Common in Clinical Isolates of Achromobacter Species and Correlate with Modifications of the Lipid A Moiety of Lipopolysaccharide. Microbiol Spectr 2023; 11:e0372922. [PMID: 36519943 PMCID: PMC9927164 DOI: 10.1128/spectrum.03729-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Achromobacter genus includes opportunistic pathogens that can cause chronic infections in immunocompromised patients, especially in people with cystic fibrosis (CF). Treatment of Achromobacter infections is complicated by antimicrobial resistance. In this study, a collection of Achromobacter clinical isolates, from CF and non-CF sources, was investigated for polymyxin B (PmB) resistance. Additionally, the effect of PmB challenge in a subset of isolates was examined and the presence of PmB-resistant subpopulations within the isolates was described. Further, chemical and mass spectrometry analyses of the lipid A of Achromobacter clinical isolates enabled the determination of the most common structures and showed that PmB challenge was associated with lipid A modifications that included the addition of glucosamine and palmitoylation and the concomitant loss of the free phosphate at the C-1 position. This study demonstrates that lipid A modifications associated with PmB resistance are prevalent in Achromobacter and that subresistant populations displaying the addition of positively charged residues and additional acyl chains to lipid A can be selected for and isolated from PmB-sensitive Achromobacter clinical isolates. IMPORTANCE Achromobacter species can cause chronic and potentially severe infections in immunocompromised patients, especially in those with cystic fibrosis. Bacteria cannot be eradicated due to Achromobacter's intrinsic multidrug resistance. We report that intrinsic resistance to polymyxin B (PmB), a last-resort antimicrobial peptide used to treat infections by multiresistant bacteria, is prevalent in Achromobacter clinical isolates; many isolates also display increased resistance upon PmB challenge. Analysis of the lipopolysaccharide lipid A moiety of several Achromobacter species reveals a penta-acylated lipid A, which in the PmB-resistant isolates was modified by the incorporation of glucosamine residues, an additional acyl chain, loss of phosphates, and hydroxylation of acyl chains, all of which can enhance PmB resistance in other bacteria. We conclude that PmB resistance, particularly in Achromobacter isolates from chronic respiratory infections, is a common phenomenon, and that Achromobacter lipid A displays modifications that may confer increased resistance to polymyxins and potentially other antimicrobial peptides.
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6
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Chen Z. Mechanisms and Clinical Relevance of Pseudomonas aeruginosa Heteroresistance. Surg Infect (Larchmt) 2023; 24:27-38. [PMID: 36622941 DOI: 10.1089/sur.2022.349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Abstract Background: Pseudomonas aeruginosa is an opportunistic pathogen that can cause various life-threatening infections. Several unique characteristics make it the ability of survivability and adaptable and develop resistance to antimicrobial agents through multiple mechanisms. Heteroresistance, which is a subpopulation-mediated resistance, has received increasing attention in recent years. Heteroresistance may lead to unexpected treatment failure if not diagnosed in time and treated properly. Therefore, heteroresistant Pseudomonas aeruginosa infections pose considerable problems for hospital-acquired infections. However, the clinical prevalence and implications of Pseudomonas aeruginosa heteroresistance have not been reviewed. Results: In this work, the aspects of the clinically reported heteroresistance of Pseudomonas aeruginosa to commonly used antibiotic agents are reviewed. The prevalence, mechanisms, and clinical relevance of each reported heteroresistant Pseudomonas aeruginosa are discussed.
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Affiliation(s)
- Zhao Chen
- College of Pharmaceutical Science, Collaborative Innovation Center of Yangtza River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, P.R. China
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7
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Zhang D, Qin Q, Qiao L. Mass spectrometry profiling of single bacterial cells reveals metabolic regulation during antibiotics induced bacterial filamentation. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.107938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Naguib M, Feldman N, Zarodkiewicz P, Shropshire H, Biamis C, El-Halfawy OM, McCain J, Dezanet C, Décout JL, Chen Y, Cosa G, Valvano MA. An evolutionary conserved detoxification system for membrane lipid-derived peroxyl radicals in Gram-negative bacteria. PLoS Biol 2022; 20:e3001610. [PMID: 35580139 PMCID: PMC9113575 DOI: 10.1371/journal.pbio.3001610] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/18/2022] [Indexed: 11/30/2022] Open
Abstract
How double-membraned Gram-negative bacteria overcome lipid peroxidation is virtually unknown. Bactericidal antibiotics and superoxide ion stress stimulate the transcription of the Burkholderia cenocepacia bcnA gene that encodes a secreted lipocalin. bcnA gene orthologs are conserved in bacteria and generally linked to a conserved upstream gene encoding a cytochrome b561 membrane protein (herein named lcoA, lipocalin-associated cytochrome oxidase gene). Mutants in bcnA, lcoA, and in a gene encoding a conserved cytoplasmic aldehyde reductase (peroxidative stress-associated aldehyde reductase gene, psrA) display enhanced membrane lipid peroxidation. Compared to wild type, the levels of the peroxidation biomarker malondialdehyde (MDA) increase in the mutants upon exposure to sublethal concentrations of the bactericidal antibiotics polymyxin B and norfloxacin. Microscopy with lipid peroxidation-sensitive fluorescent probes shows that lipid peroxyl radicals accumulate at the bacterial cell poles and septum and peroxidation is associated with a redistribution of anionic phospholipids and reduced antimicrobial resistance in the mutants. We conclude that BcnA, LcoA, and PsrA are components of an evolutionary conserved, hitherto unrecognized peroxidation detoxification system that protects the bacterial cell envelope from lipid peroxyl radicals.
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Affiliation(s)
- Marwa Naguib
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
- Department of Microbiology and Immunology, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt
| | - Nicolás Feldman
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
| | - Paulina Zarodkiewicz
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
| | - Holly Shropshire
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Christina Biamis
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
| | - Omar M. El-Halfawy
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, Saskatchewan, Canada
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Julia McCain
- Department of Chemistry and Quebec Center for Advanced Materials, McGill University, Montreal, Québec, Canada
| | - Clément Dezanet
- Department of Molecular Pharmacochemistry, Université Grenoble Alpes/CNRS, Grenoble, France
| | - Jean-Luc Décout
- Department of Molecular Pharmacochemistry, Université Grenoble Alpes/CNRS, Grenoble, France
| | - Yin Chen
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Gonzalo Cosa
- Department of Chemistry and Quebec Center for Advanced Materials, McGill University, Montreal, Québec, Canada
| | - Miguel A. Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
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9
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Perry EK, Meirelles LA, Newman DK. From the soil to the clinic: the impact of microbial secondary metabolites on antibiotic tolerance and resistance. Nat Rev Microbiol 2022; 20:129-142. [PMID: 34531577 PMCID: PMC8857043 DOI: 10.1038/s41579-021-00620-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2021] [Indexed: 02/08/2023]
Abstract
Secondary metabolites profoundly affect microbial physiology, metabolism and stress responses. Increasing evidence suggests that these molecules can modulate microbial susceptibility to commonly used antibiotics; however, secondary metabolites are typically excluded from standard antimicrobial susceptibility assays. This may in part account for why infections by diverse opportunistic bacteria that produce secondary metabolites often exhibit discrepancies between clinical antimicrobial susceptibility testing results and clinical treatment outcomes. In this Review, we explore which types of secondary metabolite alter antimicrobial susceptibility, as well as how and why this phenomenon occurs. We discuss examples of molecules that opportunistic and enteric pathogens either generate themselves or are exposed to from their neighbours, and the nuanced impacts these molecules can have on tolerance and resistance to certain antibiotics.
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Affiliation(s)
- Elena K Perry
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Lucas A Meirelles
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
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10
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Bacterial heteroresistance: an evolving novel way to combat antibiotics. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00820-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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11
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Wang KH, Zheng DH, Yuan GQ, Lin W, Li QQ. A yceI Gene Involves in the Adaptation of Ralstonia solanacearum to Methyl Gallate and Other Stresses. Microorganisms 2021; 9:microorganisms9091982. [PMID: 34576877 PMCID: PMC8472277 DOI: 10.3390/microorganisms9091982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
Ralstonia solanacearum is a plant-pathogenic bacterium causing plant bacterial wilt, and can be strongly inhibited by methyl gallate (MG). Our previous transcriptome sequencing of MG-treated R. solanacearum showed that the yceI gene AVT05_RS03545 of Rs-T02 was up-regulated significantly under MG stress. In this study, a deletion mutant (named DM3545) and an over-expression strain (named OE3545) for yceI were constructed to confirm this hypothesis. No significant difference was observed among the growth of wild-type strain, DM3545 and OE3545 strains without MG treatment. Mutant DM3545 showed a lower growth ability than that of the wild type and OE3545 strains under MG treatment, non-optimal temperature, or 1% NaCl. The ability of DM3545 for rhizosphere colonization was lower than that of the wild-type and OE3545 strains. The DM3545 strain showed substantially reduced virulence toward tomato plants than its wild-type and OE3545 counterpart. Moreover, DM3545 was more sensitive to MG in plants than the wild-type and OE3545 strains. These results suggest that YceI is involved in the adaptability of R. solanacearum to the presence of MG and the effect of other tested abiotic stresses. This protein is also possibly engaged in the virulence potential of R. solanacearum.
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Affiliation(s)
| | | | | | | | - Qi-Qin Li
- Correspondence: (D.-H.Z.); (Q.-Q.L.)
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12
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Zhang Q, Lin L, Pan Y, Chen J. Characterization of Tigecycline-Heteroresistant Klebsiella pneumoniae Clinical Isolates From a Chinese Tertiary Care Teaching Hospital. Front Microbiol 2021; 12:671153. [PMID: 34413834 PMCID: PMC8369762 DOI: 10.3389/fmicb.2021.671153] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/12/2021] [Indexed: 12/02/2022] Open
Abstract
Tigecycline has been used as one of the therapeutic choices for the treatment of infections caused by multidrug-resistant Klebsiella pneumoniae. However, the emergence of tigecycline heteroresistance has led to great challenges in treating these infections. The purpose of this study was to investigate whether tigecycline-heteroresistant K. pneumoniae (TGCHR-Kp) exists in clinical isolates, and to further characterize the underlying molecular mechanisms involved in the development of tigecycline-resistant subpopulations. Of the 268 tigecycline-susceptible clinical K. pneumoniae isolates, 69 isolates were selected as tigecycline-heteroresistant candidates in the preliminary heteroresistant phenotypic selection by a modified disk diffusion method, and only 21 strains were confirmed as TGCHR-Kp by the population analysis profile (PAP). Pulsed-field gel electrophoresis (PFGE) analysis demonstrated that all the parental TGCHR-Kp isolates were clonally unrelated, and colonies confirmed as the heteroresistant subpopulation showed no significant differences from their respective parental TGCHR-Kp isolates. Efflux pump inhibitors reversed the tigecycline susceptibility in heteroresistant subpopulations. Mutations in the ramR and soxR genes lead to upregulation of the ramA and soxS transcriptional regulators, which in turn induced overexpression of the AcrAB-TolC efflux pump genes in TGCHR-Kps-resistant subpopulations. Moreover, mutations of rpsJ were also found in resistant subpopulations, which suggested that the rpsJ mutation may also lead to tigecycline resistance. Time-kill assays showed that the efficacy of tigecycline against TGCHR-Kps was weakened, whereas the number of resistant subpopulations was enriched by the presence of tigecycline. Our findings imply that the presence of TGCHR-Kps in clinical strains causes severe challenges for tigecycline therapy in clinical practice.
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Affiliation(s)
- Qiaoyu Zhang
- Department of Nosocomial Infection Control, Fujian Medical University Union Hospital, Fuzhou, China
| | - Liping Lin
- Department of Laboratory Medicine, School of Medical Technology and Engineering, Fujian Medical University, Fuzhou, China
| | - Yuhong Pan
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, China
| | - Jiansen Chen
- Department of Nosocomial Infection Control, Fujian Medical University Union Hospital, Fuzhou, China
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13
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Patel JS, Norambuena J, Al-Tameemi H, Ahn YM, Perryman AL, Wang X, Daher SS, Occi J, Russo R, Park S, Zimmerman M, Ho HP, Perlin DS, Dartois V, Ekins S, Kumar P, Connell N, Boyd JM, Freundlich JS. Bayesian Modeling and Intrabacterial Drug Metabolism Applied to Drug-Resistant Staphylococcus aureus. ACS Infect Dis 2021; 7:2508-2521. [PMID: 34342426 DOI: 10.1021/acsinfecdis.1c00265] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present the application of Bayesian modeling to identify chemical tools and/or drug discovery entities pertinent to drug-resistant Staphylococcus aureus infections. The quinoline JSF-3151 was predicted by modeling and then empirically demonstrated to be active against in vitro cultured clinical methicillin- and vancomycin-resistant strains while also exhibiting efficacy in a mouse peritonitis model of methicillin-resistant S. aureus infection. We highlight the utility of an intrabacterial drug metabolism (IBDM) approach to probe the mechanism by which JSF-3151 is transformed within the bacteria. We also identify and then validate two mechanisms of resistance in S. aureus: one mechanism involves increased expression of a lipocalin protein, and the other arises from the loss of function of an azoreductase. The computational and experimental approaches, discovery of an antibacterial agent, and elucidated resistance mechanisms collectively hold promise to advance our understanding of therapeutic regimens for drug-resistant S. aureus.
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Affiliation(s)
- Jimmy S. Patel
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
| | - Javiera Norambuena
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Hassan Al-Tameemi
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Yong-Mo Ahn
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
| | - Alexander L. Perryman
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
| | - Xin Wang
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
| | - Samer S. Daher
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
| | - James Occi
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University − New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Riccardo Russo
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University − New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Steven Park
- Public Health Research Institute, Rutgers University − New Jersey Medical School, 225 Warren St, Newark, New Jersey 07103, United States
| | - Matthew Zimmerman
- Public Health Research Institute, Rutgers University − New Jersey Medical School, 225 Warren St, Newark, New Jersey 07103, United States
| | - Hsin-Pin Ho
- Public Health Research Institute, Rutgers University − New Jersey Medical School, 225 Warren St, Newark, New Jersey 07103, United States
| | - David S. Perlin
- Public Health Research Institute, Rutgers University − New Jersey Medical School, 225 Warren St, Newark, New Jersey 07103, United States
| | - Véronique Dartois
- Public Health Research Institute, Rutgers University − New Jersey Medical School, 225 Warren St, Newark, New Jersey 07103, United States
| | - Sean Ekins
- Collaborations in Chemistry, 5616 Hilltop Needmore Road, Fuquay-Varina, North Carolina 27526, United States
| | - Pradeep Kumar
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University − New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Nancy Connell
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University − New Jersey Medical School, Newark, New Jersey 07103, United States
| | - Jeffrey M. Boyd
- Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Joel S. Freundlich
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University − New Jersey Medical School, 185 South Orange Ave, Newark, New Jersey 07103, United States
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University − New Jersey Medical School, Newark, New Jersey 07103, United States
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14
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Sandri A, Haagensen JAJ, Veschetti L, Johansen HK, Molin S, Malerba G, Signoretto C, Boaretti M, Lleo MM. Adaptive Interactions of Achromobacter spp. with Pseudomonas aeruginosa in Cystic Fibrosis Chronic Lung Co-Infection. Pathogens 2021; 10:pathogens10080978. [PMID: 34451442 PMCID: PMC8400197 DOI: 10.3390/pathogens10080978] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/17/2021] [Accepted: 07/26/2021] [Indexed: 12/23/2022] Open
Abstract
In the lungs of patients with cystic fibrosis (CF), the main pathogen Pseudomonas aeruginosa is often co-isolated with other microbes, likely engaging in inter-species interactions. In the case of chronic co-infections, this cohabitation can last for a long time and evolve over time, potentially contributing to the clinical outcome. Interactions involving the emerging pathogens Achromobacter spp. have only rarely been studied, reporting inhibition of P. aeruginosa biofilm formation. To evaluate the possible evolution of such interplay, we assessed the ability of Achromobacter spp. isolates to affect the biofilm formation of co-isolated P. aeruginosa strains during long-term chronic co-infections. We observed both competition and cohabitation. An Achromobacter sp. isolate secreted exoproducts interfering with the adhesion ability of a co-isolated P. aeruginosa strain and affected its biofilm formation. Conversely, a clonal Achromobacter sp. strain later isolated from the same patient, as well as two longitudinal strains from another patient, did not show similar competitive behavior against its P. aeruginosa co-isolates. Genetic variants supporting the higher virulence of the competitive Achromobacter sp. isolate were found in its genome. Our results confirm that both inter-species competition and cohabitation are represented during chronic co-infections in CF airways, and evolution of these interplays can happen even at the late stages of chronic infection.
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Affiliation(s)
- Angela Sandri
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Janus Anders Juul Haagensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; (J.A.J.H.); (S.M.)
| | - Laura Veschetti
- Laboratory of Computational Genomics, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (G.M.)
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark;
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Søren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; (J.A.J.H.); (S.M.)
| | - Giovanni Malerba
- Laboratory of Computational Genomics, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (G.M.)
| | - Caterina Signoretto
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Marzia Boaretti
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
| | - Maria M. Lleo
- Department of Diagnostics and Public Health, Section of Microbiology, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy; (A.S.); (C.S.); (M.B.)
- Correspondence: ; Tel.: +39-045-802-7194
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15
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Panta PR, Doerrler WT. A link between pH homeostasis and colistin resistance in bacteria. Sci Rep 2021; 11:13230. [PMID: 34168215 PMCID: PMC8225787 DOI: 10.1038/s41598-021-92718-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/14/2021] [Indexed: 12/15/2022] Open
Abstract
Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this remain unclear. Here, we report that ∆dbcA displays alkaline pH/bicarbonate sensitivity and propose a role of DbcA in extreme colistin resistance of B. thailandensis by maintaining cytoplasmic pH homeostasis. We found that alkaline pH or presence of sodium bicarbonate displays a synergistic effect with colistin against not only extremely colistin resistant species like B. thailandensis and Serratia marcescens, but also a majority of Gram-negative and Gram-positive bacteria tested, suggesting a link between cytoplasmic pH homeostasis and colistin resistance across species. We found that lowering the level of oxygen in the growth media or supplementation of fermentable sugars such as glucose not only alleviated alkaline pH stress, but also increased colistin resistance in most bacteria tested, likely by avoiding cytoplasmic alkalinization. Our observations suggest a previously unreported link between pH, oxygen, and colistin resistance. We propose that maintaining optimal cytoplasmic pH is required for colistin resistance in a majority of bacterial species, consistent with the emerging link between cytoplasmic pH homeostasis and antibiotic resistance.
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Affiliation(s)
- Pradip R Panta
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - William T Doerrler
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA.
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16
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Lopes SP, Jorge P, Sousa AM, Pereira MO. Discerning the role of polymicrobial biofilms in the ascent, prevalence, and extent of heteroresistance in clinical practice. Crit Rev Microbiol 2021; 47:162-191. [PMID: 33527850 DOI: 10.1080/1040841x.2020.1863329] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antimicrobial therapy is facing a worrisome and underappreciated challenge, the phenomenon of heteroresistance (HR). HR has been gradually documented in clinically relevant pathogens (e.g. Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia spp., Acinetobacter baumannii, Klebsiella pneumoniae, Candida spp.) towards several drugs and is believed to complicate the clinical picture of chronic infections. This type of infections are typically mediated by polymicrobial biofilms, wherein microorganisms inherently display a wide range of physiological states, distinct metabolic pathways, diverging refractory levels of stress responses, and a complex network of chemical signals exchange. This review aims to provide an overview on the relevance, prevalence, and implications of HR in clinical settings. Firstly, related terminologies (e.g. resistance, tolerance, persistence), sometimes misunderstood and overlapped, were clarified. Factors generating misleading HR definitions were also uncovered. Secondly, the recent HR incidences reported in clinically relevant pathogens towards different antimicrobials were annotated. The potential mechanisms underlying such occurrences were further elucidated. Finally, the link between HR and biofilms was discussed. The focus was to recognize the presence of heterogeneous levels of resistance within most biofilms, as well as the relevance of polymicrobial biofilms in chronic infectious diseases and their role in resistance spreading. These topics were subject of a critical appraisal, gaining insights into the ascending clinical implications of HR in antimicrobial resistance spreading, which could ultimately help designing effective therapeutic options.
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Affiliation(s)
- Susana Patrícia Lopes
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Paula Jorge
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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17
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Liao W, Lin J, Jia H, Zhou C, Zhang Y, Lin Y, Ye J, Cao J, Zhou T. Resistance and Heteroresistance to Colistin in Escherichia coli Isolates from Wenzhou, China. Infect Drug Resist 2020; 13:3551-3561. [PMID: 33116674 PMCID: PMC7553605 DOI: 10.2147/idr.s273784] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/15/2020] [Indexed: 12/20/2022] Open
Abstract
Background Colistin is being administered as last-line therapy for patients that have failed to respond to other available antibiotics that are active against Escherichia coli. The underlying mechanisms of colistin resistance and heteroresistance remain largely uncharacterized. The present study investigated the mechanisms of resistance and heteroresistance to colistin in Escherichia coli isolates from Wenzhou, China. Materials and Methods Colistin resistance was detected by the broth microdilution method (BMD). Colistin heteroresistance was determined by population analysis profiles (PAPs). The polymerase chain reaction (PCR) was conducted to detect mcr-1, mcr-2, mcr-3, pmrA, pmrB, phoP, phoQ and mgrB, and quantitative real-time PCR (qRT-PCR) was used to determine the expression levels of mcr-1, pmrC, pmrA and pmrB. Lipid A characterization was conducted by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Results 0.69% (2/291) of Escherichia coli strains were resistant to colistin, whereas the heteroresistance rate reached 1.37% (4/291). mcr-1, the mobile colistin-resistance gene, was present in the two resistant isolates. The substitutions in PmrB were detected in the two heteroresistant isolates. The transcripts levels of the pmrCAB operon were upregulated in two of the heteroresistant isolates. carbonylcyanide m-chlorophenylhydrazone (CCCP) was able to reverse colistin resistance of all isolates tested and exhibited a significantly higher effect on colistin-heteroresistant isolates. MALDI-TOF MS indicated that the additional phosphoethanolamine (PEtn) moieties in lipid A profiles were present both in colistin-resistant and heteroresistant isolates. Conclusion The present study was the first to investigate the differential mechanisms between colistin resistance and heteroresistance. The development of colistin heteroresistance should be addressed in future clinical surveillance.
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Affiliation(s)
- Wenli Liao
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jie Lin
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Huaiyu Jia
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Cui Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Ying Zhang
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Yishuai Lin
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianzhong Ye
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianming Cao
- Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
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18
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Banerji R, Kanojiya P, Patil A, Saroj SD. Polyamines in the virulence of bacterial pathogens of respiratory tract. Mol Oral Microbiol 2020; 36:1-11. [PMID: 32979241 DOI: 10.1111/omi.12315] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/24/2020] [Accepted: 09/16/2020] [Indexed: 12/11/2022]
Abstract
Polyamines are positively charged hydrocarbons that are essential for the growth and cellular maintenance in prokaryotes and eukaryotes. Polyamines have been demonstrated to play a role in bacterial pathogenicity and biofilm formation. However, the role of extracellular polyamines as a signaling molecule in the regulation of virulence is not investigated in detail. The bacterial pathogens residing in the respiratory tract remain asymptomatic for an extended period; however, the factors that lead to symptomatic behavior are poorly understood. Further investigation to understand the relation between the host-secreted factors and virulence of pathogenic bacteria in the respiratory tract may provide insights into the pathogenesis of respiratory tract infections. Polyamines produced within the bacterial cell are generally sequestered. Therefore, the pool of extracellular polyamines formed by secretion of the commensals and the host may be one of the signaling molecules that might contribute toward the alterations in the expression of virulence factors in bacterial pathogens. Besides, convergent mechanisms of polyamine biosynthesis do exist across the border of species and genus level. Also, several novel polyamine transporters in the host and bacteria remain yet to be identified. The review focuses on the role of polyamines in the expression of virulence phenotypes and biofilm formation of the respiratory tract pathogens.
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Affiliation(s)
- Rajashri Banerji
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Poonam Kanojiya
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Amrita Patil
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Sunil D Saroj
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
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19
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Abstract
Despite increasing evidence suggesting that antibiotic heteroresistance can lead to treatment failure, the significance of this phenomena in the clinic is not well understood, because many clinical antibiotic susceptibility testing approaches lack the resolution needed to reliably classify heteroresistant strains. Here we present G0790, a new globomycin analog and potent inhibitor of the Escherichia coli type II signal peptidase LspA. We demonstrate that in addition to previously known mechanisms of resistance to LspA inhibitors, unstable genomic amplifications containing lspA can lead to modest yet biologically significant increases in LspA protein levels that confer a heteroresistance phenotype. Clinical development of antibiotics with novel mechanisms of action to kill pathogenic bacteria is challenging, in part, due to the inevitable emergence of resistance. A phenomenon of potential clinical importance that is broadly overlooked in preclinical development is heteroresistance, an often-unstable phenotype in which subpopulations of bacterial cells show decreased antibiotic susceptibility relative to the dominant population. Here, we describe a new globomycin analog, G0790, with potent activity against the Escherichia coli type II signal peptidase LspA and uncover two novel resistance mechanisms to G0790 in the clinical uropathogenic E. coli strain CFT073. Building on the previous finding that complete deletion of Lpp, the major Gram-negative outer membrane lipoprotein, leads to globomycin resistance, we also find that an unexpectedly modest decrease in Lpp levels mediated by insertion-based disruption of regulatory elements is sufficient to confer G0790 resistance and increase sensitivity to serum killing. In addition, we describe a heteroresistance phenotype mediated by genomic amplifications of lspA that result in increased LspA levels sufficient to overcome inhibition by G0790 in culture. These genomic amplifications are highly unstable and are lost after as few as two subcultures in the absence of G0790, which places amplification-containing resistant strains at high risk of being misclassified as susceptible by routine antimicrobial susceptibility testing. In summary, our study uncovers two vastly different mechanisms of resistance to LspA inhibitors in E. coli and emphasizes the importance of considering the potential impact of unstable and heterogenous phenotypes when developing antibiotics for clinical use.
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20
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Huang L, Feng Y, Zong Z. Heterogeneous resistance to colistin in Enterobacter cloacae complex due to a new small transmembrane protein. J Antimicrob Chemother 2020; 74:2551-2558. [PMID: 31169899 DOI: 10.1093/jac/dkz236] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/28/2019] [Accepted: 05/05/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Enterobacter strains can display heterogeneous resistance (heteroresistance) to colistin but the mechanisms remain largely unknown. We investigated potential mechanisms of colistin heteroresistance in an Enterobacter clinical strain, WCHECl-1060, and found a new mechanism. METHODS Strain WCHECl-1060 was subjected to WGS to identify known colistin resistance mechanisms. Tn5 insertional mutagenesis, gene knockout and complementation and shotgun cloning were employed to investigate unknown colistin heteroresistance mechanisms. RNA sequencing was performed to link the newly identified mechanism with known ones. RESULTS We showed that the phoP gene [encoding part of the PhoP-PhoQ two-component system (TCS)], the dedA(Ecl) gene (encoding an inner membrane protein of the DedA family) and the tolC gene (encoding part of the AcrAB-TolC efflux pump) are required for colistin heteroresistance. We identified a new gene, ecr, encoding a 72 amino acid transmembrane protein, which was able to mediate colistin heteroresistance. We then performed RNA sequencing and transcriptome analysis and found that in the presence of ecr the expression of phoP and the arnBCADTEF operon, which synthesizes and transfers l-Ara4N to lipid A, was increased significantly. CONCLUSIONS The small protein encoded by ecr represents a new colistin heteroresistance mechanism and is likely to mediate colistin heteroresistance via the PhoP-PhoQ TCS to act on the arnBCADTEF operon.
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Affiliation(s)
- Liang Huang
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Public Health Clinical Center of Chengdu, Chengdu, China
| | - Yu Feng
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China
| | - Zhiyong Zong
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China.,Department of Infection Control, West China Hospital, Sichuan University, Chengdu, China
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21
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Netzker T, Shepherdson EMF, Zambri MP, Elliot MA. Bacterial Volatile Compounds: Functions in Communication, Cooperation, and Competition. Annu Rev Microbiol 2020; 74:409-430. [PMID: 32667838 DOI: 10.1146/annurev-micro-011320-015542] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacteria produce a multitude of volatile compounds. While the biological functions of these deceptively simple molecules are unknown in many cases, for compounds that have been characterized, it is clear that they serve impressively diverse purposes. Here, we highlight recent studies that are uncovering the volatile repertoire of bacteria, and the functional relevance and impact of these molecules. We present work showing the ability of volatile compounds to modulate nutrient availability in the environment; alter the growth, development, and motility of bacteria and fungi; influence protist and arthropod behavior; and impact plant and animal health. We further discuss the benefits associated with using volatile compounds for communication and competition, alongside the challenges of studying these molecules and their functional roles. Finally, we address the opportunities these compounds present from commercial, clinical, and agricultural perspectives.
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Affiliation(s)
- Tina Netzker
- Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada; , , ,
| | - Evan M F Shepherdson
- Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada; , , ,
| | - Matthew P Zambri
- Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada; , , ,
| | - Marie A Elliot
- Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada; , , ,
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22
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Zwe YH, Yuk HG. Prior exposure of agriculture cephalosporin ceftiofur impaired conjugation of bla CTX-M-65 gene-bearing plasmid in Salmonella Saintpaul. J Appl Microbiol 2020; 129:1552-1565. [PMID: 32544260 DOI: 10.1111/jam.14749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/24/2020] [Accepted: 05/29/2020] [Indexed: 11/29/2022]
Abstract
AIMS Although a link between agricultural cephalosporin use and resistance in Salmonella has been demonstrated with the drug ceftiofur, the underlying mechanism of the correlation is unclear. This study investigated the impact of ceftiofur exposure in S. Saintpaul on ceftriaxone resistance, the gene expression and the conjugative transfer of the blaCTX-M-65 gene. METHODS AND RESULTS Prior ceftiofur exposure caused a twofold increase in MIC from 1024 to 2048 µg ml-1 towards ceftriaxone and increased the enzymatic activity of BlaCTX-M-65 2·2 folds from 3·46 to 7·67 nmol nitrocefin hydrolysed min-1 . A threefold upregulation in gene expression of the blaCTX-M-65 gene was also observed. Donors exposed to ceftiofur subsequently demonstrated a 2·5-fold decrease in transfer efficiency. CONCLUSIONS Prior exposure of S. Saintpaul to ceftiofur led to increased phenotypic resistance towards ceftriaxone while its ability to spread the cephalosporin resistance through conjugation, conversely, was impaired. SIGNIFICANCE AND IMPACT OF THE STUDY Findings from this study shed light on one possible mechanism in which agricultural cephalosporin exposure in Salmonella may subsequently impact clinical treatment. The finding that cephalosporin exposure in donors may hinder the subsequent spread of resistance instead of aiding it up was counter-intuitive.
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Affiliation(s)
- Y H Zwe
- Department of Food Science and Technology, National University of Singapore, Singapore
| | - H G Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
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23
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Banousi A, Evangelopoulos DS, Stylianakis A, Fandridis E, Chatziioannou S, Sipsas NV, Pneumaticos SG. A comparative study of heterogeneous antibiotic resistance of microbial populations in conventional periprosthetic tissue cultures and sonication fluid cultures of orthopaedics explanted prostheses. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2020; 30:1307-1318. [PMID: 32449081 DOI: 10.1007/s00590-020-02704-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/11/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND "Heterogeneity" describes a phenomenon where subpopulations of seemingly isogenic bacteria exhibit a range of susceptibilities to a particular antibiotic. We aim to investigate the frequency of heterogeneity among microbes isolated from infected prostheses, and its possible correlation with microbial resistance. METHODS Between May 2014 and June 2019, we investigated 234 patients, at our institution, undergoing revision arthroplasty because of loosening of the prostheses or because of periprosthetic joint infection. All patients had periprosthetic tissue culture, sonication of prosthesis and direct inoculation of Sonication fluid into blood culture bottles. We assessed the presence of heterogeneity among all pathogens isolated from infected prostheses. RESULTS Using standard non-microbiological criteria to determine periprosthetic joint infection, it was found that 143 patient (61.1%) had aseptic loosening while 91 patients (38.9%) had periprosthetic joint infection. Comparing the two methods, the results of our study showed that the method of sonication was significantly more sensitive than tissue culture [91% (83-96) vs. 43% (33-54); p < 0.005]. In this study, heterogeneity was reported in 15 cases, 16.5% of all infections and 6.4% in the total population. In our study, Staphylococcus epidermidis was the most commonly isolated strain followed by Staphylococcus aureus, at a rate of 35.2% and 19.8%, respectively. Antibiotics in which the microorganisms exhibited heterogeneous bacterial behavior most frequently were Gendamicin (5.3%), Vancomycin (4.9%). CONCLUSION There is increasing evidence that heterogeneity can lead to therapeutic failure and that the detection of this phenotype is a prerequisite for a proper antibiotic choice to have a successful therapeutic effect.
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Affiliation(s)
- Angeliki Banousi
- 3rd Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
| | - Dimitrios S Evangelopoulos
- 3rd Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Antonios Stylianakis
- Laboratory of Implant Associated Infections, Department of Microbiology, General Hospital KAT, Athens, Greece
| | - Emmanouil Fandridis
- Hand-Upper Limb and Microsurgery Department, General Hospital KAT, Athens, Greece
| | - Sofia Chatziioannou
- Nuclear Medicine Division, PET/CT section, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece
- 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, General University Hospital "ATTIKON", Athens, Greece
| | - Nikolaos V Sipsas
- Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Spyridon G Pneumaticos
- 3rd Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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24
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Campos ACDC, Andrade NL, Couto N, Mutters NT, de Vos M, Rosa ACDP, Damasco PV, Lo Ten Foe JR, Friedrich AW, Chlebowicz-Flissikowska MA, Rossen JWA. Characterization of fosfomycin heteroresistance among multidrug-resistant Escherichia coli isolates from hospitalized patients in Rio de Janeiro, Brazil. J Glob Antimicrob Resist 2020; 22:584-593. [PMID: 32389792 DOI: 10.1016/j.jgar.2020.04.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/06/2020] [Accepted: 04/17/2020] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES Urinary tract infections (UTIs) caused by multidrug-resistant Escherichia coli have become a major medical concern. Old antibiotics such as fosfomycin have become an alternative therapeutic option due to their effectiveness and, as a result, fosfomycin is now used as a first-line drug for the treatment of UTIs in many countries. Despite low resistance rates, fosfomycin heteroresistance, defined as a phenomenon where subpopulations of bacteria are resistant to high antibiotic concentrations whereas most of the bacteria are susceptible, is an underestimated problem. METHODS The frequency of heteroresistance in E. coli isolated from hospitalized patients in Brazil and its effect on susceptibility of E. coli in biofilms was studied and the isolates were molecularly characterized to reveal the mechanisms behind their fosfomycin heteroresistance using whole-genome sequencing. RESULTS A higher frequency of fosfomycin heteroresistance compared with other studies was found. In biofilms, most heteroresistant isolates were less sensitive to fosfomycin than control isolates and showed overexpression of metabolic genes thereby increasing their survival rate. Molecular characterization showed that some resistant subpopulations derived from heteroresistant isolates had a defect in their fosfomycin uptake system caused by mutations in transporter and regulatory genes, whereas others overexpressed the murA gene. None to minor effects on bacterial fitness were observed. Oxidative stress protection, virulence and metabolic genes were differentially expressed in resistant subpopulations and heteroresistant isolates. CONCLUSION Frequent detection of heteroresistance in UTIs may play a role in the failure of antibiotic treatments and should therefore be more carefully diagnosed.
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Affiliation(s)
- Ana Carolina da C Campos
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Inmunologia e Parasitologia, Boulevard 28 de Setembro, 77 - Vila Isabel, RJ-20551-030, Rio de Janeiro, Brazil; University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Nathália L Andrade
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Inmunologia e Parasitologia, Boulevard 28 de Setembro, 77 - Vila Isabel, RJ-20551-030, Rio de Janeiro, Brazil
| | - Natacha Couto
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Nico T Mutters
- Heidelberg University Hospital, Center for Infectious Diseases, Medical Microbiology and Hygiene, Im Neuenheimer Feld 672, 69120, Heidelberg, Germany
| | - Marjon de Vos
- University of Groningen, Institute for Evolutionary Life Sciences, Linnaeusborg 5(th) floor, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Ana Cláudia de P Rosa
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Inmunologia e Parasitologia, Boulevard 28 de Setembro, 77 - Vila Isabel, RJ-20551-030, Rio de Janeiro, Brazil
| | - Paulo V Damasco
- Universidade do Estado do Rio de Janeiro, Departamento de Doenças Infecciosas e Parasitárias, Boulevard 28 de Setembro, 77 - Vila Isabel, RJ-20551-030, Rio de Janeiro, Brazil; Universidade Federal do Estado do Rio de Janeiro, Departamento de Doenças Infecciosas e Parasitárias, R. Voluntários da Pátria, 107 - Botafogo, RJ- 22270-000, Rio de Janeiro, Brazil
| | - Jerome R Lo Ten Foe
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Alex W Friedrich
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Monika A Chlebowicz-Flissikowska
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - John W A Rossen
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
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Zwe YH, Chin SF, Kohli GS, Aung KT, Yang L, Yuk HG. Whole genome sequencing (WGS) fails to detect antimicrobial resistance (AMR) from heteroresistant subpopulation of Salmonella enterica. Food Microbiol 2020; 91:103530. [PMID: 32539974 DOI: 10.1016/j.fm.2020.103530] [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: 04/30/2019] [Revised: 03/28/2020] [Accepted: 04/22/2020] [Indexed: 10/24/2022]
Abstract
Due to rapidly falling costs, whole genome sequencing (WGS) is becoming an essential tool in the surveillance of antimicrobial resistance (AMR) in Salmonella enterica. Although there have been many recent works evaluating the accuracy of WGS in predicting AMR from a large number of Salmonella isolates, little attention has been devoted to deciphering the underlying causes of disagreement between the WGS genotype and experimentally determined AMR phenotype. This study analyzed the genomes of six S. enterica isolates previously obtained from raw chicken which exhibited disagreements between WGS genotype and AMR phenotype. A total of five WGS false negative predictions toward ampicillin, amoxicillin/clavulanate, colistin, and fosfomycin resistance were presented in conjunction with their corresponding empirical phenotypic and/or genetic evidence of heteroresistance. A further case study highlighting the inherent limitations of WGS to detect the underlying genetic mechanisms of colistin heteroresistance was presented. These findings implicate heteroresistance as an underlying cause for false negative WGS-based AMR predictions in S. enterica and suggest that widespread use of WGS in the surveillance of AMR in food isolates might severely underestimate true resistance rates.
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Affiliation(s)
- Ye Htut Zwe
- Department of Food Science and Technology, National University of Singapore, Singapore
| | - Seow Fong Chin
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Gurjeet Singh Kohli
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; Alfred Wegener-Institut Helmholtz-Zentrum für Polarund Meeresforschung, Bremerhaven, Germany
| | - Kyaw Thu Aung
- National Centre for Food Science, Singapore Food Agency, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore; School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Jeungpyeong-gun, Chungbuk, Republic of Korea.
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Acquisition of Colistin Resistance Links Cell Membrane Thickness Alteration with a Point Mutation in the lpxD Gene in Acinetobacter baumannii. Antibiotics (Basel) 2020; 9:antibiotics9040164. [PMID: 32268563 PMCID: PMC7235794 DOI: 10.3390/antibiotics9040164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 02/04/2023] Open
Abstract
Acinetobacter baumannii is one of the most common causes of nosocomial infections in intensive care units. Its ability to acquire diverse mechanisms of resistance limits the therapeutic choices for its treatment. This especially concerns colistin, which has been reused recently as a last-resort drug against A. baumannii. Here, we explored the impact of gaining colistin resistance on the susceptibility of A. baumannii to other antibiotics and linked colistin resistance acquisition to a gene mutation in A. baumannii. The susceptibility of 95 A. baumannii isolates revealed that 89 isolates were multi-drug resistance (MDR), and nine isolates were resistant to colistin. Subsequently, three isolates, i.e., MS48, MS50, and MS64, exhibited different resistance patterns when colistin resistance was induced and gained resistance to almost all tested antibiotics. Upon TEM examination, morphological alterations were reported for all induced isolates and a colistin-resistant clinical isolate (MS34Col-R) compared to the parental sensitive strains. Finally, genetic alterations in PmrB and LpxACD were assessed, and a point mutation in LpxD was identified in the MS64Col-R and MS34Col-R mutants, corresponding to Lys117Glu substitution in the lipid-binding domain. Our findings shed light on the implications of using colistin in the treatment of A. baumannii, especially at sub-minimum inhibitory concentrations concentrations, since cross-resistance to other classes of antibiotics may emerge, beside the rapid acquisition of resistance against colistin itself due to distinct genetic events.
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27
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Chen L, Lin J, Lu H, Zhang X, Wang C, Liu H, Zhang X, Li J, Cao J, Zhou T. Deciphering colistin heteroresistance in Acinetobacter baumannii clinical isolates from Wenzhou, China. J Antibiot (Tokyo) 2020; 73:463-470. [DOI: 10.1038/s41429-020-0289-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 01/01/2020] [Accepted: 01/30/2020] [Indexed: 11/09/2022]
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28
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Bai B, Lin Z, Pu Z, Xu G, Zhang F, Chen Z, Sun X, Zheng J, Li P, Deng Q, Yu Z. In vitro Activity and Heteroresistance of Omadacycline Against Clinical Staphylococcus aureus Isolates From China Reveal the Impact of Omadacycline Susceptibility by Branched-Chain Amino Acid Transport System II Carrier Protein, Na/Pi Cotransporter Family Protein, and Fibronectin-Binding Protein. Front Microbiol 2019; 10:2546. [PMID: 31787948 PMCID: PMC6856048 DOI: 10.3389/fmicb.2019.02546] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022] Open
Abstract
Omadacycline (Omad), a new tetracycline (Tet)-class broad-spectrum aminomethylcycline, has been reported to exhibit excellent potency against Gram-positive bacteria, including Staphylococcus aureus and Enterococci. The aim of this study was to evaluate the in vitro activity and heteroresistance characteristics of Omad in clinical S. aureus isolates from China and investigate Omad resistance mechanisms. A sample of 263 non-duplicate clinical S. aureus isolates [127 methicillin-resistant (MRSA) and 136 methicillin-sensitive (MSSA)] were collected retrospectively. Our data indicated that Omad exhibited excellent in vitro activity against both MRSA and MSSA. Omad heteroresistance frequencies were 3.17% (4/126) in MRSA and 12.78% (17/133) in MSSA. No mutations in Tet target sites, (five 16SrRNA copies and 30S ribosomal protein S10) were present in heteroresistance-derived clones, whereas Tet target site mutations contribute to induced Omad resistance in S. aureus in vitro. RNA sequencing (RNA-Seq) revealed that overexpression of branched-chain amino acid transport system II carrier protein and Na/Pi cotransporter family protein contributes to Omad heteroresistance emergence. Whole-genome sequencing demonstrated that the genetic mutation of fibronectin-binding protein (FnBP) could increase the Omad MIC. In conclusion, Omad heteroresistance risk should be considered in clinical isolates with MICs ≥ 0.5 mg/L and Omad susceptibility in S. aureus may be affected by efflux pump proteins (i.e., a branched-chain amino acid transport system II carrier protein and an Na/Pi cotransporter family protein), and FnBP.
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Affiliation(s)
- Bing Bai
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Zhiwei Lin
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Zhangya Pu
- Key Laboratory of Viral Hepatitis of Hunan Province, Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha, China
| | - Guangjian Xu
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Fan Zhang
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Zhong Chen
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Xiang Sun
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| | - Jinxin Zheng
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| | - Peiyu Li
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Qiwen Deng
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infections, Shenzhen Nanshan People's Hospital and the 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Quality Control Center of Hospital Infection Management of Shenzhen, Shenzhen Nanshan People's Hospital, Guangdong Medical University, Shenzhen, China
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Resistance and Heteroresistance to Colistin in Pseudomonas aeruginosa Isolates from Wenzhou, China. Antimicrob Agents Chemother 2019; 63:AAC.00556-19. [PMID: 31383654 DOI: 10.1128/aac.00556-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/28/2019] [Indexed: 01/26/2023] Open
Abstract
The goal was to investigate the mechanisms of colistin resistance and heteroresistance in Pseudomonas aeruginosa clinical isolates. Colistin resistance was determined by the broth microdilution method. Colistin heteroresistance was evaluated by population analysis profiling. Time-kill assays were also conducted. PCR sequencing was performed to detect the resistance genes among (hetero)resistant isolates, and quantitative real-time PCR assays were performed to determine their expression levels. Pulsed-field gel electrophoresis and multilocus sequence typing were performed. Lipid A characteristics were determined via matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS). Two resistant isolates and 9 heteroresistant isolates were selected in this study. Substitutions in PmrB were detected in 2 resistant isolates. Among heteroresistant isolates, 8 of 9 heteroresistant isolates had nonsynonymous PmrB substitutions, and 2 isolates, including 1 with a PmrB substitution, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were upregulated in PmrB- or PhoQ-substituted isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of the pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-l-arabinose (l-Ara4N) moieties in lipid A profiles in (hetero)resistant isolates. In conclusion, both colistin resistance and heteroresistance in P. aeruginosa in this study mainly involved alterations of the PmrAB regulatory system. There were strong associations between mutations in specific genetic loci for lipid A synthesis and regulation of modifications to lipid A. The transition of colistin heteroresistance to resistance should be addressed in future clinical surveillance.
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Nair RR, Sharan D, Ajitkumar P. A Minor Subpopulation of Mycobacteria Inherently Produces High Levels of Reactive Oxygen Species That Generate Antibiotic Resisters at High Frequency From Itself and Enhance Resister Generation From Its Major Kin Subpopulation. Front Microbiol 2019; 10:1842. [PMID: 31456773 PMCID: PMC6700507 DOI: 10.3389/fmicb.2019.01842] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/26/2019] [Indexed: 12/17/2022] Open
Abstract
Antibiotic-exposed bacteria produce elevated levels of reactive oxygen species (ROS), to which either they succumb or get mutated genome-wide to generate antibiotic resisters. We recently showed that mycobacterial cultures contained two subpopulations, short-sized cells (SCs; ∼10%) and normal/long-sized cells (NCs; ∼90%). The SCs were significantly more antibiotic-susceptible than the NCs. It implied that the SCs might naturally be predisposed to generate significantly higher levels of ROS than the NCs. This in turn could make the SCs more susceptible to antibiotics or generate more resisters as compared to the NCs. Investigation into this possibility showed that the SCs in the actively growing mid-log phase culture naturally generated significantly high levels of superoxide, as compared to the equivalent NCs, due to the naturally high expression of a specific NADH oxidase in the SCs. This caused labile Fe2+ leaching from 4Fe-4S proteins and elevated H2O2 formation through superoxide dismutation. Thus, the SCs of both Mycobacterium smegmatis and Mycobacterium tuberculosis inherently contained significantly higher levels of H2O2 and labile Fe2+ than the NCs. This in turn produced significantly higher levels of hydroxyl radical through Fenton reaction, promoting enhanced antibiotic resister generation from the SCs than from the NCs. The SCs, when mixed back with the NCs, at their natural proportion in the actively growing mid-log phase culture, enhanced antibiotic resister generation from the NCs, to a level equivalent to that from the unfractionated whole culture. The enhanced antibiotic resister generation from the NCs in the reconstituted SCs-NCs natural mixture was found to be due to the high levels of H2O2 secreted by the SCs. Thus, the present work unveils and documents the metabolic designs of two mycobacterial subpopulations where one subpopulation produces high ROS levels, despite higher susceptibility, to generate significantly higher number of antibiotic resisters from itself and to enhance resister generation from its kin subpopulation. These findings show the existence of an inherent natural mechanism in both the non-pathogenic and pathogenic mycobacteria to generate antibiotic resisters. The presence of the SCs and the NCs in the pulmonary tuberculosis patients’ sputum, reported by us earlier, alludes to the clinical significance of the study.
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Affiliation(s)
- Rashmi Ravindran Nair
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Deepti Sharan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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31
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Rizvanov AA, Haertlé T, Bogomolnaya L, Talebi Bezmin Abadi A. Helicobacter pylori and Its Antibiotic Heteroresistance: A Neglected Issue in Published Guidelines. Front Microbiol 2019; 10:1796. [PMID: 31456763 PMCID: PMC6700363 DOI: 10.3389/fmicb.2019.01796] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/22/2019] [Indexed: 12/19/2022] Open
Abstract
“Heteroresistance” is a widely applied term that characterizes most of the multidrug-resistant microorganisms. In microbiological practice, the word “heteroresistance” indicates diverse responses to specific antibiotics by bacterial subpopulations in the same patient. These resistant subpopulations of heteroresistant strains do not respond to antibiotic therapy in vitro or in vivo. Presently, there is no standard protocol available for the treatment of infections caused by heteroresistant Helicobacter pylori in clinical settings, at least according to recent guidelines. Thus, there is a definite need to open a new discussion on how to recognize, how to screen, and how to eliminate those problematic strains in clinical and environmental samples. Since there is great interest in developing new strategies to improve the eradication rate of anti-H. pylori treatments, the presence of heteroresistant strains/clones among clinical isolates of the bacteria should be taken into account. Indeed, increased knowledge of gastroenterologists about the existence of heteroresistance phenomena is highly required. Moreover, the accurate breakpoints should be examined/determined in order to have a solid statement of heteroresistance among the H. pylori isolates. The primary definition of heteroresistance was about coexistence of both resistant and susceptible isolates at the similar gastric microniche at once, while we think that it can be happened subsequently as well. The new guidelines should include a personalized aspect in the standard protocol to select a precise, effective antibiotic therapy for infected patients and also address the problems of regional antibiotic susceptibility profiles.
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Affiliation(s)
- Albert A Rizvanov
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Thomas Haertlé
- Biopolymers Interactions Assemblies, Institut National de la Recherche Agronomique, Nantes, France.,Department of Animal Nutrition and Feed Management, Poznan University of Life Sciences, Poznań, Poland.,Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Lydia Bogomolnaya
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia.,Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Amin Talebi Bezmin Abadi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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32
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Isayenko OY, Knysh OV, Kotsar OV, Ryzhkova TN, Dyukareva GI. Evaluation of anti-microbial activity of filtrates of Lactobacillus rhamnosus and Saccharomyces boulardii against antibiotic-resistant gram-negative bacteria. REGULATORY MECHANISMS IN BIOSYSTEMS 2019. [DOI: 10.15421/021937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The article presents the results of the first study on the influence of biologically active substances Lactobacillus rhamnosus GG ATCC 53103 and Saccharomyces boulardii, obtained according to the author`s method, on growth of gram-negative bacteria with broad medical resistance: Pseudomonas aeruginosa PR, Klebsiella pneumoniae PR, Lelliottia amnigena (Enterobacter amnigenus) PR using the spectrophotometric method. Disintegrates of L. rhamnosus GG and S. boulardii were obtained using low-frequency ultrasound processing of suspension of probiotic strains, and metabolites – through cultivation of lactobacteria and saccharomycetes in disintegrates of probiotic microorganisms. To samples of test-cultures with studied filtrates of disintegrates or metabolites we added growth medium and cultivated them (period of monitoring was 5- and 24-hours). Results of the studies were expressed as the percentage of inhibition of increment in polyresistant gram-negative bacteria under the impact of biologically active substances of probiotic microorganisms. Five-hour incubation of test-strains with the studied samples of lactobacteria led to inhibition of their growth properties by 85.6–96.7%. Growth of bacteria under the impact of substances of saccharomycetes was inhibted by 45.1–92.5%. Twenty-four hour exposure of the test-cultures in filtrates of L. rhamnosus GG and S. boulardii caused 100% inhibition of P. aeruginosa and L. amnigena polyresistant strains. Temporal interval of cultivation directly proportionally affected the extent of inhibition of growth of microorganisms: we determined direct correlation dependence within 0.789–0.991. Maximum inhibition of increment of the studied pathogens was observed under the influence of metabolites of lactobacteria, obtained by cultivating primary producers in their disintegrate. We determined a high level of anti-microbial activity of metabolites from L. rhamnosus GG and S. boulardii obtained by cultivation of probiotics in disintegrates against bacteria resistant to a broad range of preparations, which allows us to consider these substances as promising for development of anti-microbial preparations of a new generation against etiologically significant antibiotic-resistant gram-negative microorganisms.
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Lurchachaiwong W, Ruksasiri S, Wassanarungroj P, Serichantalergs O, Bodhidatta L, Crawford J, Shrestha SK, Pandey P. Determination of azithromycin heteroresistant Campylobacter jejuni in traveler's diarrhea. Gut Pathog 2019; 11:19. [PMID: 31080519 PMCID: PMC6501284 DOI: 10.1186/s13099-019-0301-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/22/2019] [Indexed: 11/10/2022] Open
Abstract
Campylobacter is the most common cause of traveler's diarrhea (TD) and human bacterial gastroenteritis. A heteroresistant Campylobacter jejuni (C. jejuni) isolate, identified by microbiological methods and characterized with molecular techniques, was obtained from a traveler in Nepal suffering TD. The presence of atypical colonies within the clear zone of inhibition was the first evidence of an atypical phenotype, leading to additional characterization of this heteroresistant strain. Antimicrobial susceptibility testing (AST) and population analysis profiling (PAP) demonstrated heteroresistance to azithromycin (AZM), a first-line antibiotic treatment for Campylobacter infections. Molecular analysis indicated a point mutation occurred on the 23S rRNA gene at the A2075G transitions, and the number of mutated gene copies was proportional to AZM resistance. Heteroresistant C. jejuni subpopulations from acute TD are likely underestimated, which may lead to treatment failures, as was the case for this patient. The presence of a heteroresistant strain in a high antibiotic environment may select for additional drug resistance and enable distribution into hospital and local communities.
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Affiliation(s)
- Woradee Lurchachaiwong
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - Supaporn Ruksasiri
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - Patcharawalai Wassanarungroj
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - Oralak Serichantalergs
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - Ladaporn Bodhidatta
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - John Crawford
- 1Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand
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Knysh OV, Isayenko OY, Voyda YV, Kizimenko OO, Babych YM. Influence of cell-free extracts of Bifidobacterium bifidum and Lactobacillus reuteri on proliferation and biofilm formation by Escherichia coli and Pseudomonas aeruginosa. REGULATORY MECHANISMS IN BIOSYSTEMS 2019. [DOI: 10.15421/021938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The development of new effective preparations for the correction of microecological disorders based on probiotic derivatives requires a comprehensive study of the biological activity of the latter. We studied the proliferative activity and biofilm formation by clinical isolates: Escherichia coli and Pseudomonas aeruginosa under the influence of cell-free extracts containing structural components and metabolites of the Bifidobacterium bifidum and Lactobacillus reuteri probiotic strains. Cell-free extracts were obtained from disintegrates and cultures of probiotics. Disintegrates were prepared by cyclic freezing-thawing of probiotic cell suspensions. The cultures were obtained by cultivating probiotic microorganisms in their own disintegrates. The obtained disintegrates and cultures were filtered. The proliferative activity of the test cultures was studied using the spectrophotometric microtiter plate method after an hour-long exposure in undiluted cell-free extracts and subsequent cultivation in a nutrient medium containing 30%vol of the studied extracts at 37 °C for 24 hours. The biofilm formation of the test cultures was studied with 30% vol content of cell-free extracts in the cultivation medium using the spectrophotometric microtiter plate method. All the studied extracts exerted a similar effect on the proliferative activity and biofilm formation by E. coli and P. aeruginosa. Exposure of the test cultures in all undiluted extracts during an hour led to a significant decrease in the optical density of the test samples: optical density of the test wells ranged from 36.5% to 49.8% of the control wells. The test cultures that were exposed to the extracts: filtrate of L. reuteri disintegrate (L), filtrate of В. bifidum disintegrate (B) and filtrate of В. bifidum culture, grown in В. bifidum disintegrate (MB) after dilution and subsequent cultivation over the next 24 hours completely restored the ability to proliferate. The proliferative activity of the test cultures that were exposed to the extracts: filtrate of L. reuteri culture, grown in L. reuteri disintegrate (ML) and filtrate of L. reuteri culture, grown in L. reuteri disintegrate supplemented with 0.8 M glycerol and 0.4 M glucose (MLG), was significantly inhibited after dilution and subsequent cultivation. The inhibition indices calculated for the ML extract were: 25.9% (E. coli) and 53.0% (P. aeruginosa). Inhibition indices calculated for the MLG extract were: 62.0% (E. coli) and 96.9% (P. aeruginosa). MLG extract had more pronounced inhibitory effect on the proliferation of the test cultures than ML extract. All the studied extracts exerted significant inhibitory effect on the biofilm formation of the test cultures. Analysis of the results of the study shows that cell-free extracts of L. reuteri culture grown in its disintegrate without supplementation or supplemented with glycerol and glucose have the highest antimicrobial activity and can be used as metabiotics to prevent overgrowth of potentially pathogenic bacteria, as well as inoculation and proliferation of pathogenic gram-negative bacteria in the gastrointestinal tract. They can be used alone or in combination with cellular probiotics to enhance their probiotic action. This study encourages further careful investigation of the biochemical composition of cell-free extracts and clarifying the mechanism of their action.
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Abstract
Bacteria exposed to stress mediated by sublethal antibiotic concentrations respond by adaptive mechanisms leading to an overall increase of antibiotic resistance. One of these mechanisms involves the release of bacterial proteins called lipocalins, which have the ability to sequester antibiotics in the extracellular space before they reach bacterial cells. We speculated that interfering with lipocalin-mediated antibiotic binding could enhance the efficacy of antibiotics to kill bacteria. In this work, we report that when combined with bactericidal antibiotics, vitamin E contributes to enhance bacterial killing both in vitro and in vivo. This adjuvant effect of vitamin E requires the presence of BcnA, a bacterial lipocalin produced by the cystic fibrosis pathogen Burkholderia cenocepacia. Since most bacteria produce lipocalins like BcnA, we propose that our findings could be translated into making novel antibiotic adjuvants to potentiate bacterial killing by existing antibiotics. Burkholderia cenocepacia is an opportunistic Gram-negative bacterium that causes serious respiratory infections in patients with cystic fibrosis. Recently, we discovered that B. cenocepacia produces the extracellular bacterial lipocalin protein BcnA upon exposure to sublethal concentrations of bactericidal antibiotics. BcnA captures a range of antibiotics outside bacterial cells, providing a global extracellular mechanism of antimicrobial resistance. In this study, we investigated water-soluble and liposoluble forms of vitamin E as inhibitors of antibiotic binding by BcnA. Our results demonstrate that in vitro, both vitamin E forms bind strongly to BcnA and contribute to reduce the MICs of norfloxacin (a fluoroquinolone) and ceftazidime (a β-lactam), both of them used as model molecules representing two different chemical classes of antibiotics. Expression of BcnA was required for the adjuvant effect of vitamin E. These results were replicated in vivo using the Galleria mellonella larva infection model whereby vitamin E treatment, in combination with norfloxacin, significantly increased larva survival upon infection in a BcnA-dependent manner. Together, our data suggest that vitamin E can be used to increase killing by bactericidal antibiotics through interference with lipocalin binding. IMPORTANCE Bacteria exposed to stress mediated by sublethal antibiotic concentrations respond by adaptive mechanisms leading to an overall increase of antibiotic resistance. One of these mechanisms involves the release of bacterial proteins called lipocalins, which have the ability to sequester antibiotics in the extracellular space before they reach bacterial cells. We speculated that interfering with lipocalin-mediated antibiotic binding could enhance the efficacy of antibiotics to kill bacteria. In this work, we report that when combined with bactericidal antibiotics, vitamin E contributes to enhance bacterial killing both in vitro and in vivo. This adjuvant effect of vitamin E requires the presence of BcnA, a bacterial lipocalin produced by the cystic fibrosis pathogen Burkholderia cenocepacia. Since most bacteria produce lipocalins like BcnA, we propose that our findings could be translated into making novel antibiotic adjuvants to potentiate bacterial killing by existing antibiotics.
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Tzeng YL, Berman Z, Toh E, Bazan JA, Turner AN, Retchless AC, Wang X, Nelson DE, Stephens DS. Heteroresistance to the model antimicrobial peptide polymyxin B in the emerging Neisseria meningitidis lineage 11.2 urethritis clade: mutations in the pilMNOPQ operon. Mol Microbiol 2018; 111:254-268. [PMID: 30338585 DOI: 10.1111/mmi.14153] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2018] [Indexed: 02/02/2023]
Abstract
Clusters of Neisseria meningitidis (Nm) urethritis among primarily heterosexual males in multiple US cities have been attributed to a unique non-encapsulated meningococcal clade (the US Nm urethritis clade, US_NmUC) within the hypervirulent clonal complex 11. Resistance to antimicrobial peptides (AMPs) is a key feature of urogenital pathogenesis of the closely related species, Neisseria gonorrhoeae. The US_NmUC isolates were found to be highly resistant to the model AMP, polymyxin B (PmB, MICs 64-256 µg ml-1 ). The isolates also demonstrated stable subpopulations of heteroresistant colonies that showed near total resistant to PmB (MICs 384-1024 µg ml-1 ) and colistin (MIC 256 µg ml-1 ) as well as enhanced LL-37 resistance. This is the first observation of heteroresistance in N. meningitidis. Consistent with previous findings, overall PmB resistance in US_NmUC isolates was due to active Mtr efflux and LptA-mediated lipid A modification. However, whole genome sequencing, variant analyses and directed mutagenesis revealed that the heteroresistance phenotypes and very high-level AMP resistance were the result of point mutations and IS1655 element movement in the pilMNOPQ operon, encoding the type IV pilin biogenesis apparatus. Cross-resistance to other classes of antibiotics was also observed in the heteroresistant colonies. High-level resistance to AMPs may contribute to the pathogenesis of US_NmUC.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Zachary Berman
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Evelyn Toh
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jose A Bazan
- Division of Infectious Diseases, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, 43210, USA.,Sexual Health Clinic, Columbus Public Health, Columbus, OH, 43210, USA
| | - Abigail Norris Turner
- Division of Infectious Diseases, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, 43210, USA
| | - Adam C Retchless
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Xin Wang
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - David S Stephens
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, 30322, USA
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Machado D, Antunes J, Simões A, Perdigão J, Couto I, McCusker M, Martins M, Portugal I, Pacheco T, Batista J, Toscano C, Viveiros M. Contribution of efflux to colistin heteroresistance in a multidrug resistant Acinetobacter baumannii clinical isolate. J Med Microbiol 2018; 67:740-749. [DOI: 10.1099/jmm.0.000741] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Diana Machado
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
| | - Jéssica Antunes
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
| | - Ana Simões
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
- Present address: Instituto Nacional de Investigação Agrária e Veterinária, I.P, Lisboa, Portugal
| | - João Perdigão
- iMed.ULisboa, Instituto de Investigação do Medicamento, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal
| | - Isabel Couto
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
| | - Matthew McCusker
- School of Food Science and Environmental Health, College of Sciences and Health, Dublin Institute of Technology, Dublin, Ireland
| | - Marta Martins
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Isabel Portugal
- iMed.ULisboa, Instituto de Investigação do Medicamento, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal
| | - Teresa Pacheco
- Serviço de Patologia Clínica, Laboratório de Microbiologia Clínica e Biologia Molecular – Hospital de Egas Moniz – Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal
| | - Judite Batista
- Serviço de Patologia Clínica, Laboratório de Microbiologia Clínica e Biologia Molecular – Hospital de Egas Moniz – Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal
| | - Cristina Toscano
- Serviço de Patologia Clínica, Laboratório de Microbiologia Clínica e Biologia Molecular – Hospital de Egas Moniz – Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal
| | - Miguel Viveiros
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
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38
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Slachmuylders L, Van Acker H, Brackman G, Sass A, Van Nieuwerburgh F, Coenye T. Elucidation of the mechanism behind the potentiating activity of baicalin against Burkholderia cenocepacia biofilms. PLoS One 2018; 13:e0190533. [PMID: 29293658 PMCID: PMC5749847 DOI: 10.1371/journal.pone.0190533] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/16/2017] [Indexed: 11/19/2022] Open
Abstract
Reduced antimicrobial susceptibility due to resistance and tolerance has become a serious threat to human health. An approach to overcome this reduced susceptibility is the use of antibiotic adjuvants, also known as potentiators. These are compounds that have little or no antibacterial effect on their own but increase the susceptibility of bacterial cells towards antimicrobial agents. Baicalin hydrate, previously described as a quorum sensing inhibitor, is such a potentiator that increases the susceptibility of Burkholderia cenocepacia J2315 biofilms towards tobramycin. The goal of the present study is to elucidate the molecular mechanisms behind the potentiating activity of baicalin hydrate and related flavonoids. We first determined the effect of multiple flavonoids on susceptibility of B. cenocepacia J2315 towards tobramycin. Increased antibiotic susceptibility was most pronounced in combination with apigenin 7-O-glucoside and baicalin hydrate. For baicalin hydrate, also other B. cepacia complex strains and other antibiotics were tested. The potentiating effect was only observed for aminoglycosides and was both strain- and aminoglycoside-dependent. Subsequently, gene expression was compared between baicalin hydrate treated and untreated cells, in the presence and absence of tobramycin. This revealed that baicalin hydrate affected cellular respiration, resulting in increased reactive oxygen species production in the presence of tobramycin. We subsequently showed that baicalin hydrate has an impact on oxidative stress via several pathways including oxidative phosphorylation, glucarate metabolism and by modulating biosynthesis of putrescine. Furthermore, our data strongly suggest that the influence of baicalin hydrate on oxidative stress is unrelated to quorum sensing. Our data indicate that the potentiating effect of baicalin hydrate is due to modulating the oxidative stress response, which in turn leads to increased tobramycin-mediated killing.
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Affiliation(s)
- Lisa Slachmuylders
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Gilles Brackman
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Andrea Sass
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | | | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- * E-mail:
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39
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El-Halfawy OM, Naguib MM, Valvano MA. Novel antibiotic combinations proposed for treatment of Burkholderia cepacia complex infections. Antimicrob Resist Infect Control 2017; 6:120. [PMID: 29204272 PMCID: PMC5702217 DOI: 10.1186/s13756-017-0279-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/17/2017] [Indexed: 12/15/2022] Open
Abstract
Effective strategies to manage Burkholderia cepacia complex (Bcc) infections in cystic fibrosis (CF) patients are lacking. We tested combinations of clinically available antibiotics and show that moxifloxacin-ceftazidime could inhibit 16 Bcc clinical isolates at physiologically achievable concentrations. Adding low dose of colistin improved the efficacy of the combo, especially at conditions mimicking CF respiratory secretions.
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Affiliation(s)
- Omar M El-Halfawy
- Department of Microbiology and Immunology, University of Western Ontario, London, ON Canada.,Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Marwa M Naguib
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Health Sciences Building, 97 Lisburn Road, Belfast, BT9 7BL UK.,Department of Microbiology and Immunology, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt
| | - Miguel A Valvano
- Department of Microbiology and Immunology, University of Western Ontario, London, ON Canada.,Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Health Sciences Building, 97 Lisburn Road, Belfast, BT9 7BL UK
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40
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Tang Y, Cawthraw S, Bagnall MC, Gielbert AJ, Woodward MJ, Petrovska L. Identification of temperature regulated factors of Campylobacter jejuni and their potential roles in virulence. AIMS Microbiol 2017; 3:885-898. [PMID: 31294195 PMCID: PMC6604965 DOI: 10.3934/microbiol.2017.4.885] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/24/2017] [Indexed: 12/23/2022] Open
Abstract
Campylobacter jejuni is the major cause of bacterial gastroenteritis in man, while it is generally regarded as a commensal of the avian gut. Consumption and handling of contaminated poultry meat products are major risk factors for human infection. The body temperature in man (37 °C) and chickens (42 °C) differ markedly, and differential gene regulation and protein expression at different temperatures may in part explain the behaviour in the two hosts. We performed proteomics analyses with C. jejuni cells grown at 37 °C and 42 °C. Time-of-flight mass spectrometry (Q-Tof) analysis was carried out after samples were digested with the Filter-Aided Sample Preparation (FASP) method and peptides were fractionated by strong anion exchanges. Differentially regulated proteins were identified by Mascot and Scaffold analyses. Triple quadrupole (QQQ) mass spectrometer analysis confirmed that a total of 33 proteins were differentially regulated between 37 °C and 42 °C. Several upregulated proteins were selected for their corresponding gene knock-out mutants to be tested for their virulence in the Galleria mellonella model. To correlate with other tissue/animal models, the GADH mutant was selected for its reduced ability to colonize chickens. At 37 °C, the mutants of outer membrane protein Omp50 and Chaperone GroEL significantly increased virulence; while at 42 °C, the mutants of YceI, Omp50, and GADH reduced virulence against Galleria mellonella compared with the wild type strains. The results of current and previous studies indicate that GADH is a virulent factor in G. mellonella and a colonization factor in chickens. The workflow of this study may prove a new way to identify stress related virulent factors. The implications of these findings are discussed for pathogenesis in the model and other hosts.
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Affiliation(s)
- Yue Tang
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Shaun Cawthraw
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Mary C Bagnall
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Adriana J Gielbert
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Martin J Woodward
- Food and Nutritional Sciences, University of Reading, Whiteknights, Reading RG6 6AP, UK
| | - Liljana Petrovska
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
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41
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42
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In Vitro Activity of Colistin and Trimethoprim/Sulfamethoxazole Against Consortia of Multidrug Resistant Non-Fermenting Gram-Negative Bacilli Isolated from Lower Respiratory Tract. Jundishapur J Microbiol 2017. [DOI: 10.5812/jjm.43081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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43
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In Vitro Activity of Colistin and Trimethoprim/Sulfamethoxazole Against Consortia of Multidrug Resistant Non-Fermenting Gram-Negative Bacilli Isolated from Lower Respiratory Tract. Jundishapur J Microbiol 2017. [DOI: 10.5812/jjm.14034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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44
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Yoshida M, Reyes SG, Tsuda S, Horinouchi T, Furusawa C, Cronin L. Time-programmable drug dosing allows the manipulation, suppression and reversal of antibiotic drug resistance in vitro. Nat Commun 2017; 8:15589. [PMID: 28593940 PMCID: PMC5472167 DOI: 10.1038/ncomms15589] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/11/2017] [Indexed: 12/30/2022] Open
Abstract
Multi-drug strategies have been attempted to prolong the efficacy of existing antibiotics, but with limited success. Here we show that the evolution of multi-drug-resistant Escherichia coli can be manipulated in vitro by administering pairs of antibiotics and switching between them in ON/OFF manner. Using a multiplexed cell culture system, we find that switching between certain combinations of antibiotics completely suppresses the development of resistance to one of the antibiotics. Using this data, we develop a simple deterministic model, which allows us to predict the fate of multi-drug evolution in this system. Furthermore, we are able to reverse established drug resistance based on the model prediction by modulating antibiotic selection stresses. Our results support the idea that the development of antibiotic resistance may be potentially controlled via continuous switching of drugs.
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Affiliation(s)
- Mari Yoshida
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
| | | | - Soichiro Tsuda
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
| | - Takaaki Horinouchi
- Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
| | - Chikara Furusawa
- Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Leroy Cronin
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
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45
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Antibiotic Capture by Bacterial Lipocalins Uncovers an Extracellular Mechanism of Intrinsic Antibiotic Resistance. mBio 2017; 8:mBio.00225-17. [PMID: 28292982 PMCID: PMC5350466 DOI: 10.1128/mbio.00225-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The potential for microbes to overcome antibiotics of different classes before they reach bacterial cells is largely unexplored. Here we show that a soluble bacterial lipocalin produced by Burkholderia cenocepacia upon exposure to sublethal antibiotic concentrations increases resistance to diverse antibiotics in vitro and in vivo These phenotypes were recapitulated by heterologous expression in B. cenocepacia of lipocalin genes from Pseudomonas aeruginosa, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus Purified lipocalin bound different classes of bactericidal antibiotics and contributed to bacterial survival in vivo Experimental and X-ray crystal structure-guided computational studies revealed that lipocalins counteract antibiotic action by capturing antibiotics in the extracellular space. We also demonstrated that fat-soluble vitamins prevent antibiotic capture by binding bacterial lipocalin with higher affinity than antibiotics. Therefore, bacterial lipocalins contribute to antimicrobial resistance by capturing diverse antibiotics in the extracellular space at the site of infection, which can be counteracted by known vitamins.IMPORTANCE Current research on antibiotic action and resistance focuses on targeting essential functions within bacterial cells. We discovered a previously unrecognized mode of general bacterial antibiotic resistance operating in the extracellular space, which depends on bacterial protein molecules called lipocalins. These molecules are highly conserved in most bacteria and have the ability to capture different classes of antibiotics outside bacterial cells. We also discovered that liposoluble vitamins, such as vitamin E, overcome in vitro and in vivo antibiotic resistance mediated by bacterial lipocalins, providing an unexpected new alternative to combat resistance by using this vitamin or its derivatives as antibiotic adjuvants.
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46
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Heteroresistance to Fluconazole Is a Continuously Distributed Phenotype among Candida glabrata Clinical Strains Associated with In Vivo Persistence. mBio 2016; 7:mBio.00655-16. [PMID: 27486188 PMCID: PMC4981708 DOI: 10.1128/mbio.00655-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida glabrata causes persistent infections in patients treated with fluconazole and often acquires resistance following exposure to the drug. Here we found that clinical strains of C. glabrata exhibit cell-to-cell variation in drug response (heteroresistance). We used population analysis profiling (PAP) to assess fluconazole heteroresistance (FLCHR) and to ask if it is a binary trait or a continuous phenotype. Thirty (57.6%) of 52 fluconazole-sensitive clinical C. glabrata isolates met accepted dichotomous criteria for FLCHR. However, quantitative grading of FLCHR by using the area under the PAP curve (AUC) revealed a continuous distribution across a wide range of values, suggesting that all isolates exhibit some degree of heteroresistance. The AUC correlated with rhodamine 6G efflux and was associated with upregulation of the CDR1 and PDH1 genes, encoding ATP-binding cassette (ABC) transmembrane transporters, implying that HetR populations exhibit higher levels of drug efflux. Highly FLCHRC. glabrata was recovered more frequently than nonheteroresistant C. glabrata from hematogenously infected immunocompetent mice following treatment with high-dose fluconazole (45.8% versus 15%, P = 0.029). Phylogenetic analysis revealed some phenotypic clustering but also variations in FLCHR within clonal groups, suggesting both genetic and epigenetic determinants of heteroresistance. Collectively, these results establish heteroresistance to fluconazole as a graded phenotype associated with ABC transporter upregulation and fluconazole efflux. Heteroresistance may explain the propensity of C. glabrata for persistent infection and the emergence of breakthrough resistance to fluconazole. Heteroresistance refers to variability in the response to a drug within a clonal cell population. This phenomenon may have crucial importance for the way we look at antimicrobial resistance, as heteroresistant strains are not detected by standard laboratory susceptibility testing and may be associated with failure of antimicrobial therapy. We describe for the first time heteroresistance to fluconazole in C. glabrata, a finding that may explain the propensity of this pathogen to acquire resistance following exposure to fluconazole and to persist despite treatment. We found that, rather than being a binary all-or-none trait, heteroresistance was a continuously distributed phenotype associated with increased expression of genes that encode energy-dependent drug efflux transporters. Moreover, we show that heteroresistance is associated with failure of fluconazole to clear infection with C. glabrata. Together, these findings provide an empirical framework for determining and quantifying heteroresistance in C. glabrata.
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47
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Hjort K, Nicoloff H, Andersson DI. Unstable tandem gene amplification generates heteroresistance (variation in resistance within a population) to colistin in Salmonella enterica. Mol Microbiol 2016; 102:274-289. [PMID: 27381382 DOI: 10.1111/mmi.13459] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 11/30/2022]
Abstract
Heteroresistance, a phenomenon where subpopulations of a bacterial isolate exhibit different susceptibilities to an antibiotic, is a growing clinical problem where the underlying genetic mechanisms in most cases remain unknown. We isolated colistin resistant mutants in Escherichia coli and Salmonella enterica serovar Typhimurium at different concentrations of colistin. Genetic analysis showed that genetically stable pmrAB point mutations were responsible for colistin resistance during selection at high drug concentrations for both species and at low concentrations for E. coli. In contrast, for S. Typhimurium mutants selected at low colistin concentrations, amplification of different large chromosomal regions conferred a heteroresistant phenotype. All amplifications included the pmrD gene, which encodes a positive regulator that up-regulates proteins that modify lipid A, and as a result increase colistin resistance. Inactivation and over-expression of the pmrD gene prevented and conferred resistance, respectively, demonstrating that the PmrD protein is required and sufficient to confer resistance. The heteroresistance phenotype is explained by the variable gene dosage of pmrD in a population, where sub-populations with different copy number of the pmrD gene show different levels of colistin resistance. We propose that variability in gene copy number of resistance genes can explain the heteroresistance observed in clinically isolated pathogenic bacteria.
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Affiliation(s)
- Karin Hjort
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Hervé Nicoloff
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
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48
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Loutet SA, El-Halfawy OM, Jassem AN, López JMS, Medarde AF, Speert DP, Davies JE, Valvano MA. Identification of synergists that potentiate the action of polymyxin B against Burkholderia cenocepacia. Int J Antimicrob Agents 2015; 46:376-80. [PMID: 26187366 DOI: 10.1016/j.ijantimicag.2015.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/19/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
Abstract
Burkholderia cenocepacia and other members of the Burkholderia cepacia complex (BCC) are highly multidrug-resistant bacteria that cause severe pulmonary infections in patients with cystic fibrosis. A screen of 2686 compounds derived from marine organisms identified molecules that could synergise with polymyxin B (PMB) to inhibit the growth of B. cenocepacia. At 1 μg/mL, five compounds synergised with PMB and inhibited the growth of B. cenocepacia by ≥70% compared with growth in PMB alone. Follow-up testing revealed that one compound from the screen, the aminocoumarin antibiotic novobiocin, synergised with PMB and colistin against tobramycin-resistant clinical isolates of B. cenocepacia and Burkholderia multivorans. In parallel, we show that novobiocin sensitivity is common among BCC species and that these bacteria are even more susceptible to an alternative aminocoumarin, clorobiocin, which also had an additive effect with PMB against B. cenocepacia. These studies support using aminocoumarin antibiotics to treat BCC infections and show that synergisers can be found to increase the efficacy of antimicrobial peptides and polymyxins against BCC bacteria.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Omar M El-Halfawy
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Agatha N Jassem
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | | | | | - David P Speert
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada; Department of Pathology, University of British Columbia, Vancouver, BC, Canada
| | - Julian E Davies
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Miguel A Valvano
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; Centre for Infection and Immunity, Queen's University Belfast, Belfast, UK.
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49
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Abstract
"Heteroresistance" describes a phenomenon where subpopulations of seemingly isogenic bacteria exhibit a range of susceptibilities to a particular antibiotic. Unfortunately, a lack of standard methods to determine heteroresistance has led to inappropriate use of this term. Heteroresistance has been recognized since at least 1947 and occurs in Gram-positive and Gram-negative bacteria. Its clinical relevance may be considerable, since more resistant subpopulations may be selected during antimicrobial therapy. However, the use of nonstandard methods to define heteroresistance, which are costly and involve considerable labor and resources, precludes evaluating the clinical magnitude and severity of this phenomenon. We review the available literature on antibiotic heteroresistance and propose recommendations for definitions and determination criteria for heteroresistant bacteria. This will help in assessing the global clinical impact of heteroresistance and developing uniform guidelines for improved therapeutic outcomes.
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Tavares-Carreón F, Patel KB, Valvano MA. Burkholderia cenocepacia and Salmonella enterica ArnT proteins that transfer 4-amino-4-deoxy-l-arabinose to lipopolysaccharide share membrane topology and functional amino acids. Sci Rep 2015; 5:10773. [PMID: 26030265 PMCID: PMC5377068 DOI: 10.1038/srep10773] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/01/2015] [Indexed: 12/27/2022] Open
Abstract
We recently demonstrated that incorporation of 4-amino-4-deoxy-l-arabinose (l-Ara4N) to the lipid A moiety of lipopolysaccharide (LPS) is required for transport of LPS to the outer membrane and viability of the Gram-negative bacterium Burkholderia cenocepacia. ArnT is a membrane protein catalyzing the transfer of l-Ara4N to the LPS molecule at the periplasmic face of the inner membrane, but its topology and mechanism of action are not well characterized. Here, we elucidate the topology of ArnT and identify key amino acids that likely contribute to its enzymatic function. PEGylation assays using a cysteineless version of ArnT support a model of 13 transmembrane helices and a large C-terminal region exposed to the periplasm. The same topological configuration is proposed for the Salmonella enterica serovar Typhimurium ArnT. Four highly conserved periplasmic residues in B. cenocepacia ArnT, tyrosine-43, lysine-69, arginine-254 and glutamic acid-493, were required for activity. Tyrosine-43 and lysine-69 span two highly conserved motifs, 42RYA44 and 66YFEKP70, that are found in ArnT homologues from other species. The same residues in S. enterica ArnT are also needed for function. We propose these aromatic and charged amino acids participate in either undecaprenyl phosphate-l-Ara4N substrate recognition or transfer of l-Ara4N to the LPS.
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Affiliation(s)
- Faviola Tavares-Carreón
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Kinnari B Patel
- Centre for Infection and Immunity, Queen's University Belfast, Belfast, BT9 7AE, United Kingdom
| | - Miguel A Valvano
- 1] Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada [2] Centre for Infection and Immunity, Queen's University Belfast, Belfast, BT9 7AE, United Kingdom
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