1
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George NL, Bennett EC, Orlando BJ. Guarding the walls: the multifaceted roles of Bce modules in cell envelope stress sensing and antimicrobial resistance. J Bacteriol 2024; 206:e0012324. [PMID: 38869304 PMCID: PMC11270860 DOI: 10.1128/jb.00123-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
Bacteria have developed diverse strategies for defending their cell envelopes from external threats. In Firmicutes, one widespread strategy is to use Bce modules-membrane protein complexes that unite a peptide-detoxifying ABC transporter with a stress response coordinating two-component system. These modules provide specific, front-line defense for a wide variety of antimicrobial peptides and small molecule antibiotics as well as coordinate responses for heat, acid, and oxidative stress. Because of these abilities, Bce modules play important roles in virulence and the development of antibiotic resistance in a variety of pathogens, including Staphylococcus, Streptococcus, and Enterococcus species. Despite their importance, Bce modules are still poorly understood, with scattered functional data in only a small number of species. In this review, we will discuss Bce module structure in light of recent cryo-electron microscopy structures of the B. subtilis BceABRS module and explore the common threads and variations-on-a-theme in Bce module mechanisms across species. We also highlight the many remaining questions about Bce module function. Understanding these multifunctional membrane complexes will enhance our understanding of bacterial stress sensing and may point toward new therapeutic targets for highly resistant pathogens.
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Affiliation(s)
- Natasha L. George
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Department of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan, USA
| | - Ellen C. Bennett
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Department of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan, USA
| | - Benjamin J. Orlando
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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2
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Di Gregorio S, Weltman G, Fabbri C, Fernández S, Zárate S, Smayevsky J, Power P, Campos J, Llarrull LI, Mollerach M. Genetic and Phenotypic Changes Related to the Development of mec-Independent Oxacillin Non-Susceptibility in ST8 Staphylococcus aureus Recovered after Antibiotic Therapy in a Patient with Bacteremia. Antibiotics (Basel) 2024; 13:554. [PMID: 38927220 PMCID: PMC11200602 DOI: 10.3390/antibiotics13060554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/30/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
The mec-independent oxacillin non-susceptible S. aureus (MIONSA) strains represent a great clinical challenge, as they are not easily detected and can lead to treatment failure. However, the responsible molecular mechanisms are still very little understood. Here, we studied four clinical ST8-MSSA-t024 isolates recovered during the course of antibiotic treatment from a patient suffering successive episodes of bacteremia. The first isolates (SAMS1, SAMS2, and SAMS3) were susceptible to cefoxitin and oxacillin. The last one (SA2) was susceptible to cefoxitin, resistant to oxacillin, lacked mec genes, and had reduced susceptibility to teicoplanin. SA2 showed higher β-lactamase activity than SAMS1. However, β-lactamase hyperproduction could not be linked to oxacillin resistance as it was not inhibited by clavulanic acid, and no genetic changes that could account for its hyperproduction were found. Importantly, we hereby report the in vivo acquisition and coexistence of different adaptive mutations in genes associated with peptidoglycan synthesis (pbp2, rodA, stp1, yjbH, and yvqF/vraT), which is possibly related with the development of oxacillin resistance and reduced susceptibility to teicoplanin in SA2. Using three-dimensional models and PBP binding assays, we demonstrated the high contribution of the SA2 PBP2 Ala450Asp mutation to the observed oxacillin resistance phenotype. Our results should be considered as a warning for physicians and microbiologists in the region, as MIONSA detection and treatment represent an important clinical challenge.
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Affiliation(s)
- Sabrina Di Gregorio
- Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autómoma de Buenos Aires 1113, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires 1113, Argentina
| | - Gabriela Weltman
- Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autómoma de Buenos Aires 1113, Argentina
| | - Carolina Fabbri
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires 1113, Argentina
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, Rosario 2000, Argentina
| | - Silvina Fernández
- Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autómoma de Buenos Aires 1113, Argentina
| | - Soledad Zárate
- Laboratorio de Bacteriología, Micología y Parasitología, Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno” (CEMIC), Ciudad Autónoma de Buenos Aires 1431, Argentina
| | - Jorgelina Smayevsky
- Laboratorio de Bacteriología, Micología y Parasitología, Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno” (CEMIC), Ciudad Autónoma de Buenos Aires 1431, Argentina
| | - Pablo Power
- Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autómoma de Buenos Aires 1113, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires 1113, Argentina
| | - Josefina Campos
- Unidad Operativa Centro Nacional de Genómica y Bioinformática, ANLIS Dr. Carlos G. Malbrán, Ciudad Autónoma de Buenos Aires 1282, Argentina
| | - Leticia Irene Llarrull
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires 1113, Argentina
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, Rosario 2000, Argentina
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, Rosario 2000, Argentina
| | - Marta Mollerach
- Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autómoma de Buenos Aires 1113, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires 1113, Argentina
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3
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Cepeda JG, Perona FL, Sanchez IB, Calvo JC, Rico A, Loeches B. Case report: Prosthetic aortic valve endocarditis due to Staphylococcus epidermidis with acquired resistance in the walK gene. Diagn Microbiol Infect Dis 2024; 108:116132. [PMID: 38056190 DOI: 10.1016/j.diagmicrobio.2023.116132] [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: 07/05/2023] [Revised: 10/29/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
We report the case of a patient with infective endocarditis on a prosthetic aortic valve due to Staphylococcus epidermidis, not a candidate for prosthetic replacement surgery. After three months of supressive treatment with dalbavancin, fever reappears, with growth of S. epidermidis. Susceptibility testing showed new-onset resistance to dalbavancin, with a mutation in walK gene.
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Affiliation(s)
- Javier Gonzalez Cepeda
- Internal Medicine, La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain.
| | - Fernando Lázaro Perona
- Microbiology, La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain
| | - Ivan Bloise Sanchez
- Microbiology, La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain
| | - Juana Cacho Calvo
- Microbiology, La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain
| | - Alicia Rico
- Clinical Microbiology and Infectious Diseases Unit. La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain
| | - Belen Loeches
- Clinical Microbiology and Infectious Diseases Unit. La Paz University Hospital. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFECC), P.° de la Castellana, 261, 28046 Madrid, Spain
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4
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Habib G, Gul H, Ahmad P, Hayat A, Rehman MU, Mohamed Moussa I, Elansary HO. Teicoplanin associated gene tcaA inactivation increases persister cell formation in Staphylococcus aureus. Front Microbiol 2023; 14:1241995. [PMID: 37901830 PMCID: PMC10611510 DOI: 10.3389/fmicb.2023.1241995] [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] [Received: 06/18/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Staphylococcus aureus is part of normal human flora and is widely associated with hospital-acquired bacteremia. S. aureus has shown a diverse array of resistance to environmental stresses and antibiotics. Methicillin-resistant S. aureus (MRSA) is on the high priority list of new antibiotics discovery and glycopeptides are considered the last drug of choice against MRSA. S. aureus has developed resistance against glycopeptides and the emergence of vancomycin-intermediate-resistant, vancomycin-resistant, and teicoplanin-resistant strains is globally reported. Teicoplanin-associated genes tcaR-tcaA-tcaB (tcaRAB) is known as the S. aureus glycopeptide resistance operon that is associated with glycopeptide resistance. Here, for the first time, the role of tcaRAB in S. aureus persister cells formation, and ΔtcaA dependent persisters' ability to resuscitate the bacterial population was explored. We recovered a clinical strain of MRSA from a COVID-19 patient which showed a high level of resistance to teicoplanin, vancomycin, and methicillin. Whole genome RNA sequencing revealed that the tcaRAB operon expression was altered followed by high expression of glyS and sgtB. The RNA-seq data revealed a significant decrease in tcaA (p = 0.008) and tcaB (p = 0.04) expression while tcaR was not significantly altered. We knocked down tcaA, tcaB, and tcaR using CRISPR-dCas9 and the results showed that when tcaA was suppressed by dCas9, a significant increase was witnessed in persister cells while tcaB suppression did not induce persistence. The results were further evaluated by creating a tcaA mutant that showed ΔtcaA formed a significant increase in persisters in comparison to the wild type. Based on our findings, we concluded that tcaA is the gene that increases persister cells and glycopeptide resistance and could be a potential therapeutic target in S. aureus.
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Affiliation(s)
- Gul Habib
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Haji Gul
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
- Faculty of Veterinary and Animal Sciences, Gomal University, Dera Ismail Khan, Pakistan
| | - Prevez Ahmad
- Department of Physics, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Azam Hayat
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Mujaddad Ur Rehman
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Ihab Mohamed Moussa
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hosam O. Elansary
- Plant Production Department, College of Food & Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
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5
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Balancing the Virulence and Antimicrobial Resistance in VISA DAP-R CA-MRSA Superbug. Antibiotics (Basel) 2022; 11:antibiotics11091159. [PMID: 36139939 PMCID: PMC9495084 DOI: 10.3390/antibiotics11091159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/23/2022] Open
Abstract
Background: Methicillin-resistant Staphylococcus aureus (MRSA) with intermediate resistance to Vancomycin (VISA) is reported worldwide. These strains frequently emerge among hospital-associated (HA)-MRSA and rarely within community-acquired (CA)-MRSA. Here, the genomic and transcriptomic adaptations distinguishing VISA daptomycin resistant (DAP-R) CA-MRSA, which emerged in a hospitalized patient under glycopeptide treatment, were explored. Methods: Whole-genome sequencing, RNA-Seq and bioinformatics were carried out. Results: Our CA-MRSA clustered in the USA400 lineage showing additional antimicrobial resistance (AMR) versus DAP and glycopeptides. Resistomics revealed adaptations related to glycopeptide, daptomycin and rifampin resistance (mprF nsSNPS and overexpression of glycopeptide and daptomycin-resistance related genes). Similar changes were detected in virulence traits (agrA HI-nsSNPs and toxin gene underexpression), in which a decrease was observed despite the abundance of virulence-related genes. Our results predicted a balance in adaptations, decreasing the virulence and biological costs to support the co-occurrence of extensive AMR in a hypervirulent genomic background. Conclusion: Our data show that VISA DAP-R CA-MRSA shifts the potential hypervirulent behavior of CA-MRSA towards the acquisition and maintenance of extensive AMR, by a decrease in virulence and biological costs mediated by a “compensatory modulatory mutation” silencing the Agr quorum-sensing cascade.
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Vimberg V, Buriánková K, Mazumdar A, Branny P, Novotná GB. Role of membrane proteins in bacterial resistance to antimicrobial peptides. Med Res Rev 2021; 42:1023-1036. [PMID: 34796517 DOI: 10.1002/med.21869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 09/19/2021] [Accepted: 10/21/2021] [Indexed: 11/07/2022]
Abstract
Several natural antimicrobial peptides (AMPs), including the novel semisynthetic lipoglycopeptide antibiotics telavancin, dalbavancin, and oritavancin, have been approved for clinical use to address the growing problem of multiple antibiotic-resistant Gram-positive bacterial infections. Nevertheless, the efficacy of these antibiotics has already been compromised. The SARS-CoV-2 pandemic led to the increased clinical use of all antibiotics, further promoting the development of bacterial resistance. Therefore, it is critical to gain a deeper understanding of the role of resistance mechanisms to minimize the consequential risks of long-term antibiotic use and misuse. Here, we summarize for the first time the current knowledge of resistance mechanisms that have been shown to cause resistance to clinically used AMPs, with particular focus on membrane proteins that have been reported to interfere with the activity of AMPs by affecting the binding of AMPs to bacteria.
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Affiliation(s)
- Vladimir Vimberg
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Karolína Buriánková
- Laboratory of Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Aninda Mazumdar
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Pavel Branny
- Laboratory of Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Gabriela B Novotná
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
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7
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Application and Perspectives of MALDI-TOF Mass Spectrometry in Clinical Microbiology Laboratories. Microorganisms 2021; 9:microorganisms9071539. [PMID: 34361974 PMCID: PMC8307939 DOI: 10.3390/microorganisms9071539] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/06/2021] [Accepted: 07/18/2021] [Indexed: 12/11/2022] Open
Abstract
Early diagnosis of severe infections requires of a rapid and reliable diagnosis to initiate appropriate treatment, while avoiding unnecessary antimicrobial use and reducing associated morbidities and healthcare costs. It is a fact that conventional methods usually require more than 24–48 h to culture and profile bacterial species. Mass spectrometry (MS) is an analytical technique that has emerged as a powerful tool in clinical microbiology for identifying peptides and proteins, which makes it a promising tool for microbial identification. Matrix assisted laser desorption ionization–time of flight MS (MALDI–TOF MS) offers a cost- and time-effective alternative to conventional methods, such as bacterial culture and even 16S rRNA gene sequencing, for identifying viruses, bacteria and fungi and detecting virulence factors and mechanisms of resistance. This review provides an overview of the potential applications and perspectives of MS in clinical microbiology laboratories and proposes its use as a first-line method for microbial identification and diagnosis.
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8
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Su M, Davis MH, Peterson J, Solis-Lemus C, Satola SW, Read TD. Effect of genetic background on the evolution of Vancomycin-Intermediate Staphylococcus aureus (VISA). PeerJ 2021; 9:e11764. [PMID: 34306830 PMCID: PMC8284308 DOI: 10.7717/peerj.11764] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/22/2021] [Indexed: 11/20/2022] Open
Abstract
Vancomycin-intermediate Staphylococcus aureus (VISA) typically arises through accumulation of chromosomal mutations that alter cell-wall thickness and global regulatory pathways. Genome-based prediction of VISA requires understanding whether strain background influences patterns of mutation that lead to resistance. We used an iterative method to experimentally evolve three important methicillin-resistant S. aureus (MRSA) strain backgrounds-(CC1, CC5 and CC8 (USA300)) to generate a library of 120 laboratory selected VISA isolates. At the endpoint, isolates had vancomycin MICs ranging from 4 to 10 μg/mL. We detected mutations in more than 150 genes, but only six genes (already known to be associated with VISA from prior studies) were mutated in all three background strains (walK, prs, rpoB, rpoC, vraS, yvqF). We found evidence of interactions between loci (e.g., vraS and yvqF mutants were significantly negatively correlated) and rpoB, rpoC, vraS and yvqF were more frequently mutated in one of the backgrounds. Increasing vancomycin resistance was correlated with lower maximal growth rates (a proxy for fitness) regardless of background. However, CC5 VISA isolates had higher MICs with fewer rounds of selection and had lower fitness costs than the CC8 VISA isolates. Using multivariable regression, we found that genes differed in their contribution to overall MIC depending on the background. Overall, these results demonstrated that VISA evolved through mutations in a similar set of loci in all backgrounds, but the effect of mutation in common genes differed with regard to fitness and contribution to resistance in different strains.
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Affiliation(s)
- Michelle Su
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Michelle H Davis
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Jessica Peterson
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Claudia Solis-Lemus
- Wisconsin Institute for Discovery and Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sarah W Satola
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Timothy D Read
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia, USA.,Department of Dermatology, School of Medicine, Emory University, Atlanta, Georgia, USA
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Liu WT, Chen EZ, Yang L, Peng C, Wang Q, Xu Z, Chen DQ. Emerging resistance mechanisms for 4 types of common anti-MRSA antibiotics in Staphylococcus aureus: A comprehensive review. Microb Pathog 2021; 156:104915. [PMID: 33930416 DOI: 10.1016/j.micpath.2021.104915] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/02/2021] [Accepted: 04/06/2021] [Indexed: 01/10/2023]
Abstract
Staphylococcus aureus is one of the leading hospital-associated and community-associated pathogens, which has caused a global public health concern. The emergence of methicillin-resistant S. aureus (MRSA) along with the widespread use of different classes of antibiotics has become a significant therapeutic challenge. Antibiotic resistance is a disturbing problem that poses a threat to humans. Treatment options for S. aureus resistant to β-lactam antibiotics include glycopeptide antibiotic, cyclic lipopeptide antibiotic, cephalosporins and oxazolidinone antibiotic. The most representative types of these antibiotics are vancomycin, daptomycin, ceftaroline and linezolid. The frequent use of the first-line drug vancomycin for MRSA treatment has increased the number of resistant strains, namely vancomycin intermediate resistant S. aureus (VISA) and vancomycin resistant S. aureus (VRSA). A systematic literature review of relevant published studies in PubMed before 2020 was conducted. In recent years, there have been some reports on the relevant resistant mechanisms of vancomycin, daptomycin, ceftaroline and linezolid. In this review, we have summarized the antibiotic molecular modes of action and different gene mutants at the whole-genome level, which will aid in further development on new drugs for effective MRSA treatment based on describing different resistance mechanisms of classic antibiotics.
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Affiliation(s)
- Wan-Ting Liu
- Microbiome Medicine Center, Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, China
| | - En-Zhong Chen
- Microbiome Medicine Center, Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, China
| | - Ling Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Chen Peng
- Department of Laboratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Qun Wang
- Department of Laboratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Zhenbo Xu
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China; College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN38163, USA; Research Institute for Food Nutrition and Human Health, Guangzhou, 510640, China; Home Economics Technology, Rajamangala University of Technology Phra Nakhon, Bangkok, Thailand.
| | - Ding-Qiang Chen
- Microbiome Medicine Center, Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, China.
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Chamon RC, Marques LM, Timenetsky J, da Costa Rachid CT, Ferreira RB, de Oliveira TL, Glatthardt T, de Oliveira Moreira L, dos Santos KR. Genome Sequence of a Highly Virulent pvl-positive Vancomycin intermediate- resistant Staphylococcus aureus Sequence Type 30. Curr Genomics 2020; 21:128-137. [PMID: 32655307 PMCID: PMC7324871 DOI: 10.2174/1389202921666200327105756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/16/2020] [Accepted: 03/16/2020] [Indexed: 11/22/2022] Open
Abstract
Background:
Staphylococcus aureus isolates expressing the Panton-Valentine Leukocidin
(PVL) have been related to a wide range of diseases. Recently, pvl-positive community-associated
methicillin-resistant S. aureus belonging to USA1100 (ST30/CC30/SCCmec IV) lineage has emerged
in Brazilian hospitals.
Objective:
The aim of this work was to sequence the genome of a pvl-positive USA1100 Vancomycin-
Intermediate-Resistant S. aureus (VISA) isolate from Rio de Janeiro, Brazil.
Methods:
The 13420 genome was sequenced using the HiSeq 2500 platform. The draft genome, plasmids
annotation, and genome analysis were performed using RAST. Comparison of the relative pvl
gene expression of six S. aureus isolates was performed by qRT-PCR.
Results:
The isolate presented the ϕPVL phage codifying for the H2b PVL protein isoform, and another
prophage carrying a PVL variant named lukF and lukS-PV.2. The 13420 genome presented a
high number of virulence determinants, such as genes codifying for serine-protease proteins, enterotoxins
(egc), the immune evasion cluster (IEC), adhesion proteins, spermine/spermidine acetyltransferase
gene (blt), superantigen-like proteins, as well as the ica operon. Point mutations at vraS, tcaA,
and tcaB genes were detected. Moreover, the PVL mRNA relative expression of the 13420 isolate was
five times higher than mRNA PVL levels of the USA300/ST8 reference strain.
Conclusion:
We described for the first time the genome sequence of a VISA isolate harboring two
pvl-associated genes and other virulence factors that may improve the USA1100/ST30 lineage fitness
and impact its pathogenicity and spreading at Brazilian hospitals.
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Affiliation(s)
- Raiane C. Chamon
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lucas M. Marques
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Bahia, Brazil
| | - Jorge Timenetsky
- Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Caio T.C. da Costa Rachid
- Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rosana B.R. Ferreira
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tamara L.R. de Oliveira
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thais Glatthardt
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lilian de Oliveira Moreira
- Laboratorio de Bacteriologia e Imunologia Clinica, Departamento de Analises Clínicas e Toxicologicas, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kátia R.N. dos Santos
- Laboratorio de Infeccao Hospitalar, Departamento de Microbiologia Medica, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Bakthavatchalam YD, Babu P, Munusamy E, Dwarakanathan HT, Rupali P, Zervos M, John Victor P, Veeraraghavan B. Genomic insights on heterogeneous resistance to vancomycin and teicoplanin in Methicillin-resistant Staphylococcus aureus: A first report from South India. PLoS One 2019; 14:e0227009. [PMID: 31887179 PMCID: PMC6936811 DOI: 10.1371/journal.pone.0227009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/09/2019] [Indexed: 12/28/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infection is an important clinical concern in patients, and is often associated with significant disease burden and metastatic infections. There is an increasing evidence of heterogeneous vancomycin-intermediate S. aureus (hVISA) associated treatment failure. In this study, we aim to understand the molecular mechanism of teicoplanin resistant MRSA (TR-MRSA) and hVISA. A total of 482 MRSA isolates were investigated for these phenotypes. Of the tested isolates, 1% were identified as TR-MRSA, and 12% identified as hVISA. A highly diverse amino acid substitution was observed in tcaRAB, vraSR, and graSR genes in TR-MRSA and hVISA strains. Interestingly, 65% of hVISA strains had a D148Q mutation in the graR gene. However, none of the markers were reliable in differentiating hVISA from TR-MRSA. Significant pbp2 upregulation was noted in three TR-MRSA strains, which had teicoplanin MICs of 16 or 32 μg/ml, whilst significant pbp4 downregulation was not noted in these strains. In our study, multiple mutations were identified in the candidate genes, suggesting a complex evolutionary pathway involved in the development of TR-MRSA and hVISA strains.
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Affiliation(s)
| | - Priyanka Babu
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | - Elakkiya Munusamy
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | | | - Priscilla Rupali
- Infectious Diseases Training and Research Center (IDTRC), Christian Medical College, Vellore, India
| | - Marcus Zervos
- Infectious Diseases, Henry Ford Health System, Detroit, Michigan, United States of America
| | - Peter John Victor
- Department of critical care unit, Christian Medical College, Vellore, India
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
- * E-mail:
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12
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Cong Y, Yang S, Rao X. Vancomycin resistant Staphylococcus aureus infections: A review of case updating and clinical features. J Adv Res 2019; 21:169-176. [PMID: 32071785 PMCID: PMC7015472 DOI: 10.1016/j.jare.2019.10.005] [Citation(s) in RCA: 233] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/02/2019] [Accepted: 10/09/2019] [Indexed: 01/08/2023] Open
Abstract
MRSA infection is a global threat to public health. Vancomycin is one of the first-line drugs for the treatment of MRSA infections. MRSA with complete resistance to vancomycin have emerged in recent years. The total number of VRSA isolates is updated in this paper. Resistance mechanisms, characteristics of VRSA infections, as well as clinical treatments are reviewed.
The infection caused by methicillin-resistant Staphylococcus aureus (MRSA) is a global threat to public health. Vancomycin remains one of the first-line drugs for the treatment of MRSA infections. However, S. aureus isolates with complete resistance to vancomycin have emerged in recent years. Vancomycin-resistant S. aureus (VRSA) is mediated by a vanA gene cluster, which is transferred from vancomycin-resistant enterococcus. Since the first VRSA isolate was recovered from Michigan, USA in 2002, 52 VRSA strains have been isolated worldwide. In this paper, we review the latest progresses in VRSA, highlighting its resistance mechanism, characteristics of VRSA infections, as well as clinical treatments.
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Affiliation(s)
- Yanguang Cong
- Department of Clinical Laboratory, Traditional Medicine Hospital Affiliated to Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Sijin Yang
- Department of Cardiovascular Disease, Traditional Medicine Hospital Affiliated to Southwest Medical University, Luzhou, Sichuan 646000, China
| | - Xiancai Rao
- Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Chongqing 400038, China
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13
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Abstract
Dating back to the 1960s, initial studies on the staphylococcal cell wall were driven by the need to clarify the mode of action of the first antibiotics and the resistance mechanisms developed by the bacteria. During the following decades, the elucidation of the biosynthetic path and primary composition of staphylococcal cell walls was propelled by advances in microbial cell biology, specifically, the introduction of high-resolution analytical techniques and molecular genetic approaches. The field of staphylococcal cell wall gradually gained its own significance as the complexity of its chemical structure and involvement in numerous cellular processes became evident, namely its versatile role in host interactions, coordination of cell division and environmental stress signaling.This chapter includes an updated description of the anatomy of staphylococcal cell walls, paying particular attention to information from the last decade, under four headings: high-resolution analysis of the Staphylococcus aureus peptidoglycan; variations in peptidoglycan composition; genetic determinants and enzymes in cell wall synthesis; and complex functions of cell walls. The latest contributions to a more precise picture of the staphylococcal cell envelope were possible due to recently developed state-of-the-art microscopy and spectroscopy techniques and to a wide combination of -omics approaches, that are allowing to obtain a more integrative view of this highly dynamic structure.
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Affiliation(s)
- Rita Sobral
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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14
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Silveira ACO, Caierão J, Silva CI, Anzai EK, McCulloch JA, d'Azevedo PA, Sincero TCM. Impact of mutations in hVISA isolates on decreased susceptibility to vancomycin, through population analyses profile - area under curve (PAP-AUC). Diagn Microbiol Infect Dis 2019; 95:114854. [PMID: 31366440 DOI: 10.1016/j.diagmicrobio.2019.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 04/10/2019] [Accepted: 06/06/2019] [Indexed: 10/26/2022]
Abstract
We analyzed sequences of graSR, vraSR, walKR and rpoB genes in hVISA from Brazil. Five isolates showed mutations in at least one gene. rpoB H481N and graS T224I were the most frequent mutations, followed by graR D148Q and walK A468T. Our study reinforces the heterogeneity of genetic patterns among hVISA.
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Affiliation(s)
- A C O Silveira
- UFSC - Federal University of Santa Catarina, Florianópolis, - SC, Brazil; FURB - Regional University of Blumenau, Blumenau, - SC, Brazil.
| | - J Caierão
- UFRGS - Federal University of Rio Grande do Sul, Porto Alegre, - RS, Brazil
| | - C I Silva
- UFSC - Federal University of Santa Catarina, Florianópolis, - SC, Brazil
| | - E K Anzai
- FURB - Regional University of Blumenau, Blumenau, - SC, Brazil
| | - J A McCulloch
- USP - University of São Paulo, São Paulo, - SP, Brazil
| | - P A d'Azevedo
- UFCSPA - Federal University of Health Sciences of Porto Alegre, Porto Alegre, - RS, Brazil
| | - T C M Sincero
- UFSC - Federal University of Santa Catarina, Florianópolis, - SC, Brazil
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15
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Abstract
Staphylococcus aureus is capable of becoming resistant to all classes of antibiotics clinically available and resistance can develop through de novo mutations in chromosomal genes or through acquisition of horizontally transferred resistance determinants. This review covers the most important antibiotics available for treatment of S. aureus infections and a special emphasis is dedicated to the current knowledge of the wide variety of resistance mechanisms that S. aureus employ to withstand antibiotics. Since resistance development has been inevitable for all currently available antibiotics, new therapies are continuously under development. Besides development of new small molecules affecting cell viability, alternative approaches including anti-virulence and bacteriophage therapeutics are being investigated and may become important tools to combat staphylococcal infections in the future.
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16
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Wu D, Wang Z, Wang H, Sun L, Chen Y, Ji S, Shi K, Yu Y. Predominance of ST5-II-t311 clone among healthcare-associated methicillin-resistant Staphylococcus aureus isolates recovered from Zhejiang, China. Int J Infect Dis 2018; 71:107-112. [PMID: 29698703 DOI: 10.1016/j.ijid.2018.04.798] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/17/2018] [Accepted: 04/17/2018] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES To determine the molecular characteristics and antimicrobial susceptibility of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) in Zhejiang Province. METHODS A total of 391 HA-MRSA isolates were collected from 12 hospitals in five cities of Zhejiang Province, between January 2012 and May 2013. Susceptibility to vancomycin, teicoplanin, linezolid, tigecycline, and daptomycin was determined. Resistant isolates were screened for resistance mutations. Ten isolates from each hospital were then chosen at random for molecular typing. RESULTS The isolates showed good susceptibility to all five anti-MRSA agents; only five sporadic non-susceptible isolates were detected. CC5/ST5-MRSA-II-t311 (39/120, 32.5%) was found to be the predominant HA-MRSA clone and was spread between the different hospitals in Hangzhou. CC5/ST5-MRSA-II-t002 was the most prevalent clone in Ningbo, while CC239/ST239-MRSA was epidemic only in certain hospitals in Wenzhou and Shaoxing. Fifteen ST59 isolates (15/120, 12.5%) were identified among the HA-MRSA isolates. CONCLUSIONS CC5/ST5-MRSA-II-t311 has become the predominant HA-MRSA clone in Hangzhou, Zhejiang Province. ST59 MRSA has spread into hospitals. The isolates showed good susceptibility to all five anti-MRSA agents.
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Affiliation(s)
- Dandan Wu
- Department of Infectious Diseases, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zhengan Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haiping Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lu Sun
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Department of Hospital Epidemiology and Infection Control, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shujuan Ji
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Keren Shi
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, Zhejiang, China.
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17
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Lin LC, Chang SC, Ge MC, Liu TP, Lu JJ. Novel single-nucleotide variations associated with vancomycin resistance in vancomycin-intermediate Staphylococcus aureus. Infect Drug Resist 2018; 11:113-123. [PMID: 29403293 PMCID: PMC5783010 DOI: 10.2147/idr.s148335] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Prolonged vancomycin usage may cause methicillin-resistant Staphylococcus aureus to become vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA). Mechanisms of vancomycin resistance of VISA and hVISA are still unclear. In this study, analyses of nucleotide sequence variations in 30 vancomycin-sensitive S. aureus (VSSA), 41 hVISA and 16 VISA isolates revealed 29 single-nucleotide variations in 12 genes (fmtC, graR, graS, htrA, mecA, pbp2, pbp4, srtA, tcaA, upps, vicK and vraR) that are related to cell wall synthesis or the two-component system. Six of these 29 single-nucleotide variations were novel and resulted in the following amino acid changes: Q692E in FmtC; T278I, P306L and I311T in HtrA; and I63V and K101E in Upps. Since P306L and I311T in HtrA and I63V in Upps were present in the majority (76.7%–86.7%) of VSSA isolates, these three amino acid variations may not be associated with vancomycin resistance. The other three amino acid variations (T278I in HtrA, K101E in Upps and Q692E in FmtC) were present in the majority (87.5%–93.8%) of hVISA and VISA isolates, but only in a small number (22.9%–25.7%) of VSSA isolates, suggesting that they are associated with vancomycin resistance.
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Affiliation(s)
- Lee-Chung Lin
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Shih-Cheng Chang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Mao-Cheng Ge
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Tsui-Ping Liu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
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18
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Luciferase Reporter Gene System to Detect Cell Wall Stress Stimulon Induction in Staphylococcus aureus. Methods Mol Biol 2018; 1440:139-50. [PMID: 27311670 DOI: 10.1007/978-1-4939-3676-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Luciferase reporter gene fusions provide an extremely rapid and sensitive tool for measuring the induction or repression of stress responses in bacteria. Staphylococcus aureus activates the expression of a cell wall stress stimulon (CWSS) in response to the inhibition or disruption of cell wall synthesis. The highly sensitive promoter-reporter gene fusion construct psas016 p-luc+ can be used to quantify and compare any changes in CWSS expression levels and induction kinetics. Potential uses of this system include identifying and characterizing novel cell wall-targeting antibacterial agents, identifying genomic loci influencing cell envelope synthesis and detecting changes in CWSS expression that could be linked to decreased antibiotic susceptibility profiles in clinical isolates.
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Tran TT, Miller WR, Shamoo Y, Arias CA. Targeting cell membrane adaptation as a novel antimicrobial strategy. Curr Opin Microbiol 2016; 33:91-96. [PMID: 27458841 DOI: 10.1016/j.mib.2016.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 01/19/2023]
Abstract
Emergence of antibiotic resistance is an example of the incredible plasticity of bacteria to survive in all environments. The search for new antibiotics active against traditional targets is more challenging due not only to the lack of novel natural products to fulfill the current clinical needs against multidrug-resistant (MDR) bacteria, but also for the possible 'collateral' effects on the human microbiota. Thus, non-traditional approaches to combat MDR bacteria have been proposed. Here, we discuss the possibility of targeting the membrane response to the antibiotic attack (cell membrane adaptation) as a viable strategy to increase the activity of current antimicrobials, enhance the activity of the innate immune system and prevent development of resistance during therapy using the three-component regulatory system LiaFSR of enterococci as a model.
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Affiliation(s)
- Truc T Tran
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States
| | - William R Miller
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States
| | - Yousif Shamoo
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX, United States
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States; Molecular Genetics and Antimicrobial Resistance Unit, Universidad El Bosque, Bogota, Colombia; International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia.
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Comparative mechanistic studies of brilacidin, daptomycin, and the antimicrobial peptide LL16. Antimicrob Agents Chemother 2014; 58:5136-45. [PMID: 24936592 DOI: 10.1128/aac.02955-14] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Brilacidin (PMX30063) has shown potent bactericidal activity against drug-resistant and -susceptible strains of multiple Gram-negative and Gram-positive pathogens. In this study, we demonstrate that brilacidin causes membrane depolarization in the Gram-positive bacterium Staphylococcus aureus, to an extent comparable to that caused by the lipopeptidic drug daptomycin. Transcriptional profiling of Staphylococcus aureus by deep sequencing shows that the global response to brilacidin treatment is well correlated to those of treatment with daptomycin and the cationic antimicrobial peptide LL37 and mostly indicates abrogation of cell wall and membrane functions. Furthermore, the upregulation of various chaperones and proteases by brilacidin and daptomycin indicates that cytoplasmic protein misfolding stress may be a contributor to the mechanism of action of these drugs. These stress responses were orchestrated mainly by three two-component systems, GraSR, VraSR, and NsaSR, which have been implicated in virulence and drug resistance against other clinically available antibiotics.
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Genome sequence-based discriminator for vancomycin-intermediate Staphylococcus aureus. J Bacteriol 2013; 196:940-8. [PMID: 24363339 DOI: 10.1128/jb.01410-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Vancomycin is the mainstay of treatment for patients with Staphylococcus aureus infections, and reduced susceptibility to vancomycin is becoming increasingly common. Accordingly, the development of rapid and accurate assays for the diagnosis of vancomycin-intermediate S. aureus (VISA) will be critical. We developed and applied a genome-based machine-learning approach for discrimination between VISA and vancomycin-susceptible S. aureus (VSSA) using 25 whole-genome sequences. The resulting machine-learning model, based on 14 gene parameters, including 3 molecular typing markers and 11 genes implicated in reduced vancomycin susceptibility, is able to unambiguously distinguish between the VISA and VSSA isolates analyzed here despite the fact that they do not form evolutionarily distinct groups. As such, the model is able to discriminate based on specific genomic markers of antibiotic susceptibility rather than overall sequence relatedness. Subsequent evaluation of the model using leave-one-out validation yielded a classification accuracy of 84%. The machine-learning approach described here provides a generalized framework for the application of genome sequence analysis to the classification of bacteria that differ with respect to clinically relevant phenotypes and should be particularly useful in defining the genomic features that underlie antibiotic resistance.
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