1
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Lohsen S, Stephens DS. Inducible Mega-Mediated Macrolide Resistance Confers Heteroresistance in Streptococcus pneumoniae. Antimicrob Agents Chemother 2023; 67:e0131922. [PMID: 36847556 PMCID: PMC10019249 DOI: 10.1128/aac.01319-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
In Streptococcus pneumoniae (Spn), the 5.4 to 5.5 kb Macrolide Genetic Assembly (Mega) encodes an efflux pump (Mef[E]) and a ribosomal protection protein (Mel) conferring antibiotic resistance to commonly used macrolides in clinical isolates. We found the macrolide-inducible Mega operon provides heteroresistance (more than 8-fold range in MICs) to 14- and 15-membered ring macrolides. Heteroresistance is commonly missed during traditional clinical resistance screens but is highly concerning as resistant subpopulations can persist despite treatment. Spn strains containing the Mega element were screened via Etesting and population analysis profiling (PAP). All Mega-containing Spn strains screened displayed heteroresistance by PAP. The heteroresistance phenotype was linked to the mRNA expression of the mef(E)/mel operon of the Mega element. Macrolide induction uniformly increased Mega operon mRNA expression across the population, and heteroresistance was eliminated. A deletion of the 5' regulatory region of the Mega operon results in a mutant deficient in induction as well as in heteroresistance. The mef(E)L leader peptide sequence of the 5' regulatory region was required for induction and heteroresistance. Treatment with a noninducing 16-membered ring macrolide antibiotic did not induce the mef(E)/mel operon or eliminate the heteroresistance phenotype. Thus, inducibility of the Mega element by 14- and 15-membered macrolides and heteroresistance are linked in Spn. The stochastic variation in mef(E)/mel expression in a Spn population containing Mega provides the basis for heteroresistance.
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Affiliation(s)
- Sarah Lohsen
- Departments of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David S. Stephens
- Departments of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Departments of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
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2
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Depta J, Niedźwiedzka-Rystwej P. The Phenomenon of Antibiotic Resistance in the Polar Regions: An Overview of the Global Problem. Infect Drug Resist 2023; 16:1979-1995. [PMID: 37034396 PMCID: PMC10081531 DOI: 10.2147/idr.s369023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/02/2022] [Indexed: 04/11/2023] Open
Abstract
The increasing prevalence of antibiotic resistance is a global problem in human and animal health. This leads to a reduction in the therapeutic effectiveness of the measures used so far and to the limitation of treatment options, which may pose a threat to human health and life. The problem of phenomenon of antibiotic resistance affects more and more the polar regions. This is due to the increase in tourist traffic and the number of people staying at research stations, unmodernised sewage systems in inhabited areas, as well as the migration of animals or the movement of microplastics, which may contain resistant bacteria. Research shows that the presence of antibiotic resistance genes is more dominant in zones of human and wildlife influence than in remote areas. In a polluted environment, there is evidence of a direct correlation between human activity and the spread and survival of antibiotic-resistant bacteria. Attention should be paid to the presence of resistance to synthetic and semi-synthetic antibiotics in the polar regions, which is likely to be correlated with human presence and activity, and possible steps to be taken. We need to understand many more aspects of this, such as bacterial epigenetics and environmental stress, in order to develop effective strategies for minimizing the spread of antibiotic resistance genes. Studying the diversity and abundance of antibiotic resistance genes in regions with less anthropogenic activity could provide insight into the diversity of primary genes and explain the historical evolution of antibiotic resistance.
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Affiliation(s)
- Julia Depta
- Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland
| | - Paulina Niedźwiedzka-Rystwej
- Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland
- Correspondence: Paulina Niedźwiedzka-Rystwej, Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland, Tel +48 91 444 15 15, Email
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3
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Dewachter L, Dénéréaz J, Liu X, de Bakker V, Costa C, Baldry M, Sirard JC, Veening JW. Amoxicillin-resistant Streptococcus pneumoniae can be resensitized by targeting the mevalonate pathway as indicated by sCRilecs-seq. eLife 2022; 11:75607. [PMID: 35748540 PMCID: PMC9363119 DOI: 10.7554/elife.75607] [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: 11/16/2021] [Accepted: 06/23/2022] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance in the important opportunistic human pathogen Streptococcus pneumoniae is on the rise. This is particularly problematic in the case of the β-lactam antibiotic amoxicillin, which is the first-line therapy. It is therefore crucial to uncover targets that would kill or resensitize amoxicillin-resistant pneumococci. To do so, we developed a genome-wide, single-cell based, gene silencing screen using CRISPR interference called sCRilecs-seq (subsets of CRISPR interference libraries extracted by fluorescence activated cell sorting coupled to next generation sequencing). Since amoxicillin affects growth and division, sCRilecs-seq was used to identify targets that are responsible for maintaining proper cell size. Our screen revealed that downregulation of the mevalonate pathway leads to extensive cell elongation. Further investigation into this phenotype indicates that it is caused by a reduced availability of cell wall precursors at the site of cell wall synthesis due to a limitation in the production of undecaprenyl phosphate (Und-P), the lipid carrier that is responsible for transporting these precursors across the cell membrane. The data suggest that, whereas peptidoglycan synthesis continues even with reduced Und-P levels, cell constriction is specifically halted. We successfully exploited this knowledge to create a combination treatment strategy where the FDA-approved drug clomiphene, an inhibitor of Und-P synthesis, is paired up with amoxicillin. Our results show that clomiphene potentiates the antimicrobial activity of amoxicillin and that combination therapy resensitizes amoxicillin-resistant S. pneumoniae. These findings could provide a starting point to develop a solution for the increasing amount of hard-to-treat amoxicillin-resistant pneumococcal infections. Streptococcus pneumoniae is a bacterium that can cause pneumonia, meningitis and other life-threatening illnesses in humans. Currently, many S. pneumoniae infections are treated with the antibiotic amoxicillin, which kills the bacteria by weakening a structure known as the cell wall that surrounds each bacterium. However, more and more S. pneumoniae cells are becoming resistant to amoxicillin, making it harder to treat such infections. We need new ways to effectively treat S. pneumoniae infections in humans. One potential strategy would be to combine amoxicillin with another drug that boosts the activity of amoxicillin so that it is able to kill the resistant bacteria. Two drugs that both target the same process in cells are more likely to boost each other’s activity. Therefore, Dewachter et al. decided to search for another drug that also weakens the cell wall of S. pneumoniae. The team first developed a new screening approach called sCRilecs-seq to silence individual genes in single S. pneumoniae cells. By looking at many cells that each had a different gene that was no longer active, the team were able to identify several genes that when silenced resulted in the cells becoming longer than normal cells (a sign the bacteria may have weak cell walls). Further experiments revealed that the cell walls of these bacteria were weaker than normal cells due to a shortage in a cell wall building material known as undecaprenyl phosphate. Dewachter et al. then demonstrated that combining an existing drug known as clomiphene – which is known to inhibit undecaprenyl phosphate production and is currently used to treat infertility in humans – together with amoxicillin is able to effectively kill S. pneumoniae that are resistant to amoxicillin alone. Clomiphene also boosted the activity of amoxicillin against S. pneumoniae that remain sensitive to the antibiotic. Before this new drug combination may be used to help treat S. pneumoniae infections in human patients, further experiments will be needed to find out the optimum dose of clomiphene to use with amoxicillin. In the future, the new screening approach developed by Dewachter et al. may also prove useful to other researchers studying a wide range of biological questions.
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Affiliation(s)
- Liselot Dewachter
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Julien Dénéréaz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Xue Liu
- Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, China
| | - Vincent de Bakker
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | | | | | | | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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4
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Mohamed MA, Nasr M, Elkhatib WF, Eltayeb WN, Elshamy AA, El-Sayyad GS. Nanobiotic formulations as promising advances for combating MRSA resistance: susceptibilities and post-antibiotic effects of clindamycin, doxycycline, and linezolid. RSC Adv 2021; 11:39696-39706. [PMID: 35494109 PMCID: PMC9044563 DOI: 10.1039/d1ra08639a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/08/2021] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial activity and post-antibiotic effects (PAEs) are both important parameters in determination of the dosage regimen of antimicrobial agents. In the present study, antimicrobial activity and PAEs of clindamycin, doxycycline, linezolid, and their nanobiotic formulations were evaluated against two methicillin resistant Staphylococcus aureus clinical isolates (MRSA) encoded (MRSA-S1 and MRSA-S2). Nanobiotic formulations increased the susceptibility of MRSA isolates by 4–64 folds as compared to their conventional ones. The PAE values were determined after exposure of MRSA isolates for 1 h to 10× the MICs of the tested antibiotics. The duration of PAEs were recorded after bacterial growth in Mueller Hinton broth (MHB) free from antibiotic has been restored. The PAE values for MRSA-S1 were 2.5 h for the conventional antibiotics. However, the PAEs for nanobiotics were 4 h for both clindamycin and linezolid, while 3 h for doxycycline. For MRSA-S2, linezolid and linezolid nanobiotics PAEs were 3 h. PAEs of clindamycin and clindamycin nanobiotics were 3.75 h and 4 h, respectively. Doxycycline and doxycycline nanobiotics revealed the same PAEs patterns of 3.5 h. The findings of the current study may positively influence the pharmacodynamics of the antibiotics and consequently the dosage regimen of nanobiotics as well as on their clinical outcome. Novel nanobiotic formulations of clindamycin, doxycycline, and linezolid were evaluated for the post-antibiotic effects against biofilm forming methicillin resistant Staphylococcus aureus (MRSA).![]()
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Affiliation(s)
- Mennatallah A Mohamed
- Microbiology Department, Faculty of Pharmacy, Misr International University Cairo 19648 Egypt
| | - Maha Nasr
- Pharmaceutics and Industrial Pharmacy Department, Faculty of Pharmacy, Ain Shams University, African Union Organization St. Abbassia Cairo 11566 Egypt
| | - Walid F Elkhatib
- Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, African Union Organization St. Abbassia Cairo 11566 Egypt +20-2-24051107 +20-2-24051120.,Department of Microbiology & Immunology, Faculty of Pharmacy, Galala University New Galala City Suez Egypt
| | - Wafaa N Eltayeb
- Microbiology Department, Faculty of Pharmacy, Misr International University Cairo 19648 Egypt
| | - Aliaa A Elshamy
- Microbiology and Public Health Department, Faculty of Pharmacy and Drug Technology, Heliopolis University for Sustainable Development Cairo Belbes Road Cairo 11788 Egypt
| | - Gharieb S El-Sayyad
- Department of Microbiology & Immunology, Faculty of Pharmacy, Galala University New Galala City Suez Egypt.,Drug Radiation Research Department, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA) Cairo Egypt +20-2-22749298 +20-2-22727413
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5
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Akiyama T, Kim M. Stochastic response of bacterial cells to antibiotics: its mechanisms and implications for population and evolutionary dynamics. Curr Opin Microbiol 2021; 63:104-108. [PMID: 34325154 DOI: 10.1016/j.mib.2021.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/22/2021] [Accepted: 07/01/2021] [Indexed: 11/20/2022]
Abstract
The effectiveness of antibiotics against bacterial infections has been declining due to the emergence of resistance. Precisely understanding the response of bacteria to antibiotics is critical to maximizing antibiotic-induced bacterial eradication while minimizing the emergence of antibiotic resistance. Cell-to-cell heterogeneity in antibiotic susceptibility is observed across various bacterial species for a wide range of antibiotics. Heterogeneity in antibiotic susceptibility is not always due to the genetic differences. Rather, it can be caused by non-genetic mechanisms such as stochastic gene expression and biased partitioning upon cell division. Heterogeneous susceptibility leads to the stochastic growth and death of individual cells and stochastic fluctuations in population size. These fluctuations have important implications for the eradication of bacterial populations and the emergence of genotypic resistance.
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Affiliation(s)
- Tatsuya Akiyama
- Department of Physics, Emory University, Atlanta, GA, 30322, USA; Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, 30322, USA
| | - Minsu Kim
- Department of Physics, Emory University, Atlanta, GA, 30322, USA; Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, 30322, USA; Emory Antibiotic Resistance Center, Emory University, Atlanta, GA, 30322, USA.
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6
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Liu X, Kimmey JM, Matarazzo L, de Bakker V, Van Maele L, Sirard JC, Nizet V, Veening JW. Exploration of Bacterial Bottlenecks and Streptococcus pneumoniae Pathogenesis by CRISPRi-Seq. Cell Host Microbe 2020; 29:107-120.e6. [PMID: 33120116 DOI: 10.1016/j.chom.2020.10.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/27/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that causes invasive diseases, including pneumonia, with greater health risks upon influenza A virus (IAV) co-infection. To facilitate pathogenesis studies in vivo, we developed an inducible CRISPR interference system that enables genome-wide fitness testing in one sequencing step (CRISPRi-seq). We applied CRISPRi-seq to assess bottlenecks and identify pneumococcal genes important in a murine pneumonia model. A critical bottleneck occurs at 48 h with few bacteria causing systemic infection. This bottleneck is not present during IAV superinfection, facilitating identification of pneumococcal pathogenesis-related genes. Top in vivo essential genes included purA, encoding adenylsuccinate synthetase, and the cps operon required for capsule production. Surprisingly, CRISPRi-seq indicated no fitness-related role for pneumolysin during superinfection. Interestingly, although metK (encoding S-adenosylmethionine synthetase) was essential in vitro, it was dispensable in vivo. This highlights advantages of CRISPRi-seq over transposon-based genetic screens, as all genes, including essential genes, can be tested for pathogenesis potential.
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Affiliation(s)
- Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Jacqueline M Kimmey
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Laura Matarazzo
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Laurye Van Maele
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Jean-Claude Sirard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland.
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7
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Alexander HK, MacLean RC. Stochastic bacterial population dynamics restrict the establishment of antibiotic resistance from single cells. Proc Natl Acad Sci U S A 2020; 117:19455-19464. [PMID: 32703812 PMCID: PMC7431077 DOI: 10.1073/pnas.1919672117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A better understanding of how antibiotic exposure impacts the evolution of resistance in bacterial populations is crucial for designing more sustainable treatment strategies. The conventional approach to this question is to measure the range of concentrations over which resistant strain(s) are selectively favored over a sensitive strain. Here, we instead investigate how antibiotic concentration impacts the initial establishment of resistance from single cells, mimicking the clonal expansion of a resistant lineage following mutation or horizontal gene transfer. Using two Pseudomonas aeruginosa strains carrying resistance plasmids, we show that single resistant cells have <5% probability of detectable outgrowth at antibiotic concentrations as low as one-eighth of the resistant strain's minimum inhibitory concentration (MIC). This low probability of establishment is due to detrimental effects of antibiotics on resistant cells, coupled with the inherently stochastic nature of cell division and death on the single-cell level, which leads to loss of many nascent resistant lineages. Our findings suggest that moderate doses of antibiotics, well below the MIC of resistant strains, may effectively restrict de novo emergence of resistance even though they cannot clear already-large resistant populations.
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Affiliation(s)
- Helen K Alexander
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - R Craig MacLean
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
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8
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Antibiotic Resistance and Epigenetics: More to It than Meets the Eye. Antimicrob Agents Chemother 2020; 64:AAC.02225-19. [PMID: 31740560 DOI: 10.1128/aac.02225-19] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery of antibiotics in the last century is considered one of the most important achievements in the history of medicine. Antibiotic usage has significantly reduced morbidity and mortality associated with bacterial infections. However, inappropriate use of antibiotics has led to emergence of antibiotic resistance at an alarming rate. Antibiotic resistance is regarded as a major health care challenge of this century. Despite extensive research, well-documented biochemical mechanisms and genetic changes fail to fully explain mechanisms underlying antibiotic resistance. Several recent reports suggest a key role for epigenetics in the development of antibiotic resistance in bacteria. The intrinsic heterogeneity as well as transient nature of epigenetic inheritance provides a plausible backdrop for high-paced emergence of drug resistance in bacteria. The methylation of adenines and cytosines can influence mutation rates in bacterial genomes, thus modulating antibiotic susceptibility. In this review, we discuss a plethora of recently discovered epigenetic mechanisms and their emerging roles in antibiotic resistance. We also highlight specific epigenetic mechanisms that merit further investigation for their role in antibiotic resistance.
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9
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Bacterial Heterogeneity and Antibiotic Survival: Understanding and Combatting Persistence and Heteroresistance. Mol Cell 2019; 76:255-267. [DOI: 10.1016/j.molcel.2019.09.028] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 12/20/2022]
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10
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Wu TF, Chen YC, Wang WC, Fang YC, Fukuoka S, Pride DT, Pak OS. A Rapid and Low-Cost Pathogen Detection Platform by Using a Molecular Agglutination Assay. ACS CENTRAL SCIENCE 2018; 4:1485-1494. [PMID: 30555900 PMCID: PMC6276042 DOI: 10.1021/acscentsci.8b00447] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Indexed: 05/10/2023]
Abstract
Rapid and low-cost pathogen diagnostic approaches are critical for clinical decision-making procedures. Cultivating bacteria often takes days to identify pathogens and provide antimicrobial susceptibilities. The delay in diagnosis may result in compromised treatment and inappropriate antibiotic use. Over the past decades, molecular-based techniques have significantly shortened pathogen identification turnaround time with high accuracy. However, these assays often use complex fluorescent labeling and nucleic acid amplification processes, which limit their use in resource-limited settings. In this work, we demonstrate a wash-free molecular agglutination assay with a straightforward mixing and incubation step that significantly simplifies procedures of molecular testing. By targeting the 16S rRNA gene of pathogens, we perform a rapid pathogen identification within 30 min on a dark-field imaging microfluidic cytometry platform. The dark-field images with low background noise can be obtained using a narrow beam scanning technique with off-the-shelf complementary metal oxide semiconductor (CMOS) imagers such as smartphone cameras. We utilize a machine learning algorithm to deconvolute topological features of agglutinated clusters and thus quantify the abundance of bacteria. Consequently, we unambiguously distinguish Escherichia coli positive from other E. coli negative among 50 clinical urinary tract infection samples with 96% sensitivity and 100% specificity. Furthermore, we also apply this quantitative detection approach to achieve rapid antimicrobial susceptibility testing within 3 h. This work exhibits easy-to-use protocols, high sensitivity, and short turnaround time for point-of-care testing uses.
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Affiliation(s)
- Tsung-Feng Wu
- VOR,
Inc., Atkinson Hall #1412,
9500 Gilman Drive, La Jolla, California 92093, United States
- (T.-F.W.) E-mail:
| | - Yu-Chen Chen
- VOR,
Inc., Atkinson Hall #1412,
9500 Gilman Drive, La Jolla, California 92093, United States
| | - Wei-Chung Wang
- VOR,
Inc., Atkinson Hall #1412,
9500 Gilman Drive, La Jolla, California 92093, United States
| | - Yen-Chi Fang
- VOR,
Inc., Atkinson Hall #1412,
9500 Gilman Drive, La Jolla, California 92093, United States
| | - Scott Fukuoka
- Department
of Bioengineering, Santa Clara University, 500 El Camino Real, Santa Clara, California 95053, United States
| | - David T. Pride
- Department
of Pathology, University of California at
San Diego, 9500 Gilman Drive #0612, La Jolla, California 92093, United States
| | - On Shun Pak
- Department
of Mechanical Engineering, Santa Clara University, 500 El Camino Real, Santa Clara, California 95053, United States
- (O.S.P.) E-mail:
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11
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Dockerty P, Edens JG, Tol MB, Morales Angeles D, Domenech A, Liu Y, Hirsch AKH, Veening JW, Scheffers DJ, Witte MD. Bicyclic enol cyclocarbamates inhibit penicillin-binding proteins. Org Biomol Chem 2018; 15:894-910. [PMID: 28045164 DOI: 10.1039/c6ob01664b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Natural products form attractive leads for the development of chemical probes and drugs. The antibacterial lipopeptide Brabantamide A contains an unusual enol cyclocarbamate and we used this scaffold as inspiration for the synthesis of a panel of enol cyclocarbamate containing compounds. By equipping the scaffold with different groups, we identified structural features that are essential for antibacterial activity. Some of the derivatives block incorporation of hydroxycoumarin carboxylic acid-amino d-alanine into the newly synthesized peptidoglycan. Activity-based protein-profiling experiments revealed that the enol carbamates inhibit a specific subset of penicillin-binding proteins in B. subtilis and S. pneumoniae.
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Affiliation(s)
- Paul Dockerty
- Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands.
| | - Jerre G Edens
- Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands.
| | - Menno B Tol
- Molecular Microbiology, Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Danae Morales Angeles
- Molecular Microbiology, Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Arnau Domenech
- Molecular Genetics, Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Yun Liu
- Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands.
| | - Anna K H Hirsch
- Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands.
| | - Jan-Willem Veening
- Molecular Genetics, Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Dirk-Jan Scheffers
- Molecular Microbiology, Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Martin D Witte
- Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands.
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12
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Rosenthal K, Oehling V, Dusny C, Schmid A. Beyond the bulk: disclosing the life of single microbial cells. FEMS Microbiol Rev 2017; 41:751-780. [PMID: 29029257 PMCID: PMC5812503 DOI: 10.1093/femsre/fux044] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 09/08/2017] [Indexed: 01/08/2023] Open
Abstract
Microbial single cell analysis has led to discoveries that are beyond what can be resolved with population-based studies. It provides a pristine view of the mechanisms that organize cellular physiology, unbiased by population heterogeneity or uncontrollable environmental impacts. A holistic description of cellular functions at the single cell level requires analytical concepts beyond the miniaturization of existing technologies, defined but uncontrolled by the biological system itself. This review provides an overview of the latest advances in single cell technologies and demonstrates their potential. Opportunities and limitations of single cell microbiology are discussed using selected application-related examples.
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Affiliation(s)
- Katrin Rosenthal
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | - Verena Oehling
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | - Christian Dusny
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
| | - Andreas Schmid
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
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13
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Quorum sensing integrates environmental cues, cell density and cell history to control bacterial competence. Nat Commun 2017; 8:854. [PMID: 29021534 PMCID: PMC5636887 DOI: 10.1038/s41467-017-00903-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 08/03/2017] [Indexed: 01/08/2023] Open
Abstract
Streptococcus pneumoniae becomes competent for genetic transformation when exposed to an autoinducer peptide known as competence-stimulating peptide (CSP). This peptide was originally described as a quorum-sensing signal, enabling individual cells to regulate competence in response to population density. However, recent studies suggest that CSP may instead serve as a probe for sensing environmental cues, such as antibiotic stress or environmental diffusion. Here, we show that competence induction can be simultaneously influenced by cell density, external pH, antibiotic-induced stress, and cell history. Our experimental data is explained by a mathematical model where the environment and cell history modify the rate at which cells produce or sense CSP. Taken together, model and experiments indicate that autoinducer concentration can function as an indicator of cell density across environmental conditions, while also incorporating information on environmental factors or cell history, allowing cells to integrate cues such as antibiotic stress into their quorum-sensing response. This unifying perspective may apply to other debated quorum-sensing systems. Peptide CSP regulates natural competence in pneumococci and has been proposed as a quorum-sensing signal or a probe for sensing environmental cues. Here, the authors show that CSP levels can indeed act as an indicator of cell density and also incorporate information on environmental factors or cell history.
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14
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Transcriptional Repressor PtvR Regulates Phenotypic Tolerance to Vancomycin in Streptococcus pneumoniae. J Bacteriol 2017; 199:JB.00054-17. [PMID: 28484041 DOI: 10.1128/jb.00054-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/26/2017] [Indexed: 02/05/2023] Open
Abstract
Reversible or phenotypic tolerance to antibiotics within microbial populations has been implicated in treatment failure of chronic infections and development of persister cells. However, the molecular mechanisms regulating phenotypic drug tolerance are largely unknown. In this study, we identified a four-gene operon in Streptococcus pneumoniae that contributes to phenotypic tolerance to vancomycin (ptv). RNA sequencing, quantiative reverse transcriptase PCR, and transcriptional luciferase reporter experiments revealed that transcription of the ptv operon (consisting of ptvR, ptvA, ptvB, and ptvC) is induced by exposure to vancomycin. Further investigation showed that transcription of the ptv operon is repressed by PtvR, a PadR family repressor. Transcriptional induction of the ptv operon by vancomycin was achieved by transcriptional derepression of this locus, which was mediated by PtvR. Importantly, fully derepressing ptvABC by deleting ptvR or overexpressing the ptv operon with an exogenous promoter significantly enhanced vancomycin tolerance. Gene deletion analysis revealed that PtvA, PtvB, and PtvC are all required for the PtvR-regulated phenotypic tolerance to vancomycin. Finally, the results of an electrophoretic mobility shift assay with recombinant PtvR showed that PtvR represses the transcription of the ptv operon by binding to two palindromic sequences within the ptv promoter. Together, the ptv locus represents an inducible system in S. pneumoniae in response to stressful conditions, including those caused by antibiotics.IMPORTANCE Reversible or phenotypic tolerance to antibiotics within microbial populations is associated with treatment failure of bacterial diseases, but the underlying mechanisms regulating phenotypic drug tolerance remain obscure. This study reports our finding of a multigene locus that contributes to inducible tolerance to vancomycin in Streptococcus pneumoniae, an important opportunistic human pathogen. The vancomycin tolerance phenotype depends on the PtvR transcriptional repressor and three predicted membrane-associated proteins encoded by the ptv locus. This represents the first example of a gene locus in S. pneumoniae that is responsible for antibiotic tolerance and has important implications for further understanding bacterial responses and phenotypic tolerance to antibiotic treatment in this and other pathogens.
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15
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Liu X, Gallay C, Kjos M, Domenech A, Slager J, van Kessel SP, Knoops K, Sorg RA, Zhang JR, Veening JW. High-throughput CRISPRi phenotyping identifies new essential genes in Streptococcus pneumoniae. Mol Syst Biol 2017; 13:931. [PMID: 28490437 PMCID: PMC5448163 DOI: 10.15252/msb.20167449] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Genome‐wide screens have discovered a large set of essential genes in the opportunistic human pathogen Streptococcus pneumoniae. However, the functions of many essential genes are still unknown, hampering vaccine development and drug discovery. Based on results from transposon sequencing (Tn‐seq), we refined the list of essential genes in S. pneumoniae serotype 2 strain D39. Next, we created a knockdown library targeting 348 potentially essential genes by CRISPR interference (CRISPRi) and show a growth phenotype for 254 of them (73%). Using high‐content microscopy screening, we searched for essential genes of unknown function with clear phenotypes in cell morphology upon CRISPRi‐based depletion. We show that SPD_1416 and SPD_1417 (renamed to MurT and GatD, respectively) are essential for peptidoglycan synthesis, and that SPD_1198 and SPD_1197 (renamed to TarP and TarQ, respectively) are responsible for the polymerization of teichoic acid (TA) precursors. This knowledge enabled us to reconstruct the unique pneumococcal TA biosynthetic pathway. CRISPRi was also employed to unravel the role of the essential Clp‐proteolytic system in regulation of competence development, and we show that ClpX is the essential ATPase responsible for ClpP‐dependent repression of competence. The CRISPRi library provides a valuable tool for characterization of pneumococcal genes and pathways and revealed several promising antibiotic targets.
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Affiliation(s)
- Xue Liu
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands.,Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Clement Gallay
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Morten Kjos
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands.,Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Arnau Domenech
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Sebastiaan P van Kessel
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Kèvin Knoops
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Robin A Sorg
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands .,Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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16
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Levin-Reisman I, Ronin I, Gefen O, Braniss I, Shoresh N, Balaban NQ. Antibiotic tolerance facilitates the
evolution of resistance. Science 2017; 355:826-830. [DOI: 10.1126/science.aaj2191] [Citation(s) in RCA: 634] [Impact Index Per Article: 90.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/16/2017] [Indexed: 12/24/2022]
Abstract
Controlled experimental evolution during
antibiotic treatment can help to explain the
processes leading to antibiotic resistance in
bacteria. Recently, intermittent antibiotic
exposures have been shown to lead rapidly to the
evolution of tolerance—that is, the ability to
survive under treatment without developing
resistance. However, whether tolerance delays or
promotes the eventual emergence of resistance is
unclear. Here we used in vitro evolution
experiments to explore this question. We found
that in all cases, tolerance preceded resistance.
A mathematical population-genetics model showed
how tolerance boosts the chances for resistance
mutations to spread in the population. Thus,
tolerance mutations pave the way for the rapid
subsequent evolution of resistance. Preventing the
evolution of tolerance may offer a new strategy
for delaying the emergence of resistance.
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Affiliation(s)
- Irit Levin-Reisman
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Irine Ronin
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Orit Gefen
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ilan Braniss
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Noam Shoresh
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Nathalie Q. Balaban
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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17
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Collective Resistance in Microbial Communities by Intracellular Antibiotic Deactivation. PLoS Biol 2016; 14:e2000631. [PMID: 28027306 PMCID: PMC5189934 DOI: 10.1371/journal.pbio.2000631] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/23/2016] [Indexed: 11/29/2022] Open
Abstract
The structure and composition of bacterial communities can compromise antibiotic efficacy. For example, the secretion of β-lactamase by individual bacteria provides passive resistance for all residents within a polymicrobial environment. Here, we uncover that collective resistance can also develop via intracellular antibiotic deactivation. Real-time luminescence measurements and single-cell analysis demonstrate that the opportunistic human pathogen Streptococcus pneumoniae grows in medium supplemented with chloramphenicol (Cm) when resistant bacteria expressing Cm acetyltransferase (CAT) are present. We show that CAT processes Cm intracellularly but not extracellularly. In a mouse pneumonia model, more susceptible pneumococci survive Cm treatment when coinfected with a CAT-expressing strain. Mathematical modeling predicts that stable coexistence is only possible when antibiotic resistance comes at a fitness cost. Strikingly, CAT-expressing pneumococci in mouse lungs were outcompeted by susceptible cells even during Cm treatment. Our results highlight the importance of the microbial context during infectious disease as a potential complicating factor to antibiotic therapy. Antibiotic-resistant bacterial infections are on the rise and pose a serious threat to society. The influence of genetic resistance mechanisms on antibiotic therapy is well described. However, other factors, such as epigenetic resistance or the impact of the environment on antibiotic therapy, are less well understood. Here, we describe and characterize a mechanism of noninherited antibiotic resistance that enables the survival and outgrowth of genetically susceptible bacteria during antibiotic therapy. We show that bacteria expressing the resistance factor chloramphenicol (Cm) acetyltransferase (CAT) can potently deactivate Cm in their immediate environment. The reduced Cm concentration then allows for the outgrowth of genetically susceptible bacteria in the same environment. Mathematical modeling demonstrates the presence of a parameter space in which stable coexistence between Cm-susceptible and -resistant bacteria is possible during antibiotic therapy, which we validated using single-cell analyses. Strikingly, mixed culture experiments in which mice were infected with both Cm-susceptible and -resistant pneumococci revealed that Cm-sensitive “freeloader” bacteria even outcompeted resistant bacteria during antibiotic therapy. Together, we show that the microbial context during infection is a potential complicating factor to antibiotic treatment outcomes.
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The biofilm inhibitor Carolacton inhibits planktonic growth of virulent pneumococci via a conserved target. Sci Rep 2016; 6:29677. [PMID: 27404808 PMCID: PMC4939601 DOI: 10.1038/srep29677] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/21/2016] [Indexed: 12/13/2022] Open
Abstract
New antibacterial compounds, preferentially exploiting novel cellular targets, are urgently needed to fight the increasing resistance of pathogens against conventional antibiotics. Here we demonstrate that Carolacton, a myxobacterial secondary metabolite previously shown to damage Streptococcus mutans biofilms, inhibits planktonic growth of Streptococcus pneumoniae TIGR4 and multidrug-resistant clinical isolates of serotype 19A at nanomolar concentrations. A Carolacton diastereomer is inactive in both streptococci, indicating a highly specific interaction with a conserved cellular target. S. mutans requires the eukaryotic-like serine/threonine protein kinase PknB and the cysteine metabolism regulator CysR for susceptibility to Carolacton, whereas their homologues are not needed in S. pneumoniae, suggesting a specific function for S. mutans biofilms only. A bactericidal effect of Carolacton was observed for S. pneumoniae TIGR4, with a reduction of cell numbers by 3 log units. The clinical pneumonia isolate Sp49 showed immediate growth arrest and cell lysis, suggesting a bacteriolytic effect of Carolacton. Carolacton treatment caused a reduction in membrane potential, but not membrane integrity, and transcriptome analysis revealed compensatory reactions of the cell. Our data show that Carolacton might have potential for treating pneumococcal infections.
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19
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Fisher JF, Mobashery S. β-Lactam Resistance Mechanisms: Gram-Positive Bacteria and Mycobacterium tuberculosis. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025221. [PMID: 27091943 DOI: 10.1101/cshperspect.a025221] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The value of the β-lactam antibiotics for the control of bacterial infection has eroded with time. Three Gram-positive human pathogens that were once routinely susceptible to β-lactam chemotherapy-Streptococcus pneumoniae, Enterococcus faecium, and Staphylococcus aureus-now are not. Although a fourth bacterium, the acid-fast (but not Gram-positive-staining) Mycobacterium tuberculosis, has intrinsic resistance to earlier β-lactams, the emergence of strains of this bacterium resistant to virtually all other antibiotics has compelled the evaluation of newer β-lactam combinations as possible contributors to the multidrug chemotherapy required to control tubercular infection. The emerging molecular-level understanding of these resistance mechanisms used by these four bacteria provides the conceptual framework for bringing forward new β-lactams, and new β-lactam strategies, for the future control of their infections.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
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