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Ong JS, Taylor TD, Yong CC, Khoo BY, Sasidharan S, Choi SB, Ohno H, Liong MT. Lactobacillus plantarum USM8613 Aids in Wound Healing and Suppresses Staphylococcus aureus Infection at Wound Sites. Probiotics Antimicrob Proteins 2021; 12:125-137. [PMID: 30659503 DOI: 10.1007/s12602-018-9505-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This study aimed to elucidate the targets and mechanisms of anti-staphylococcal effects from bioactive metabolites produced by lactic acid bacteria. We aimed to better understand the safety and efficacy of these bioactive metabolites in in vivo systems, typically at topical sites. The cell-free supernatant and protein-rich fraction from Lactobacillus plantarum USM8613 inhibited staphyloxanthin biosynthesis, reduced (p < 0.05) the cell number of Staphylococcus aureus by 106 CFU/mL and reduced biofilm thickness by 55% in S. aureus-infected porcine skins. Genome-wide analysis and gene expression analysis illustrated the production of several plantaricins, especially the plantaricins EF and JK that enhanced the anti-staphylococcal effects of L. plantarum USM8613. In vivo data using rats showed that the protein-rich fraction from L. plantarum USM8613 exerted wound healing properties via direct inhibition of S. aureus and promoted innate immunity, in which the expression of β-defensin was significantly (p < 0.05) upregulated by 3.8-fold. The protein fraction from L. plantarum USM8613 also significantly enhanced (p < 0.05) the production of cytokines and chemokines through various stages of wound recovery. Using ∆atl S. aureus, the protein-rich fraction from L. plantarum USM8613 exerted inhibitory activity via targeting the atl gene in S. aureus. Taken altogether, our present study illustrates the potential of L. plantarum USM8613 in aiding wound healing, suppressing of S. aureus infection at wound sites and promoting host innate immunity.
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Affiliation(s)
- Jia Sin Ong
- School of Industrial Technology, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Todd D Taylor
- Laboratory for Microbiome Sciences, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.,USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Cheng Chung Yong
- School of Industrial Technology, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Boon Yin Khoo
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Sreenivasan Sasidharan
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Sy Bing Choi
- School of Data Sciences, Perdana University, 43400, Selangor, Malaysia
| | - Hiroshi Ohno
- USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800, Penang, Malaysia. .,Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.
| | - Min Tze Liong
- School of Industrial Technology, Universiti Sains Malaysia, 11800, Penang, Malaysia. .,USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800, Penang, Malaysia.
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Su HN, Li K, Zhao LS, Yuan XX, Zhang MY, Liu SM, Chen XL, Liu LN, Zhang YZ. Structural Visualization of Septum Formation in Staphylococcus warneri Using Atomic Force Microscopy. J Bacteriol 2020; 202:e00294-20. [PMID: 32900866 PMCID: PMC7484183 DOI: 10.1128/jb.00294-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/17/2020] [Indexed: 12/16/2022] Open
Abstract
Cell division of Staphylococcus adopts a "popping" mechanism that mediates extremely rapid separation of the septum. Elucidating the structure of the septum is crucial for understanding this exceptional bacterial cell division mechanism. Here, the septum structure of Staphylococcus warneri was extensively characterized using high-speed time-lapse confocal microscopy, atomic force microscopy, and electron microscopy. The cells of S. warneri divide in a fast popping manner on a millisecond timescale. Our results show that the septum is composed of two separable layers, providing a structural basis for the ultrafast daughter cell separation. The septum is formed progressively toward the center with nonuniform thickness of the septal disk in radial directions. The peptidoglycan on the inner surface of double-layered septa is organized into concentric rings, which are generated along with septum formation. Moreover, this study signifies the importance of new septum formation in initiating new cell cycles. This work unravels the structural basis underlying the popping mechanism that drives S. warneri cell division and reveals a generic structure of the bacterial cell.IMPORTANCE This work shows that the septum of Staphylococcus warneri is composed of two layers and that the peptidoglycan on the inner surface of the double-layered septum is organized into concentric rings. Moreover, new cell cycles of S. warneri can be initiated before the previous cell cycle is complete. This work advances our knowledge about a basic structure of bacterial cell and provides information on the double-layered structure of the septum for bacteria that divide with the "popping" mechanism.
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Affiliation(s)
- Hai-Nan Su
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Kang Li
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Long-Sheng Zhao
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiao-Xue Yuan
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Meng-Yao Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Si-Min Liu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Lu-Ning Liu
- College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
- College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Shin J, Magar KBS, Lee J, Kim KS, Lee YR. Design, synthesis, and discovery of novel oxindoles bearing 3-heterocycles as species-specific and combinatorial agents in eradicating Staphylococcus species. Sci Rep 2019; 9:8012. [PMID: 31527598 PMCID: PMC6746789 DOI: 10.1038/s41598-019-44304-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/14/2019] [Indexed: 01/12/2023] Open
Abstract
A series of new functionalized 3-indolylindolin-2-ones, 3-(1-methylpyrrol-2-yl)indolin-2-ones, and 3-(thiophen-2-yl)indolin-2-ones were synthesized by using novel indium (III)-catalysed reaction of various 3-diazoindolin-2-ones with indoles, 1-methylpyrrole, or thiophene via one-pot procedure. The newly synthesized compounds were characterized and screened for their in vitro antibacterial activity against various Staphylococcus species, including methicillin-resistant Staphylococcus aureus. results revealed that five compounds KS15, KS16, KS17, KS19, and KS20 exhibited potent and specific antibacterial activity against Staphylococcus species albeit inactive against Gram-negative bacteria. Especially, compounds exhibited superior antibacterial potency against Staphylococcus epidermidis compared to the reference drug streptomycin. The most potential compound KS16 also increased the susceptibility of Staphylococcus aureus to ciprofloxacin, gentamicin, kanamycin, and streptomycin. Among them, KS16 was found to be a synergistic compound with gentamicin and kanamycin. Furthermore, the cellular level of autolysin protein was increased from the KS16-treated Staphylococcus aureus cells. Finally, in vitro CCK-8 assays showed that KS16 exhibited no cytotoxicity at the minimum inhibitory concentrations used for killing Staphylococcus species. From all our results, novel oxindole compounds directly have lethal action or boost existing antibiotic power with the reduction of doses and toxicity in the treatment of multidrug-resistant Staphylococcus species.
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Affiliation(s)
- Jonghoon Shin
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan, 46241, Republic of Korea
| | | | - Jungwoon Lee
- Environmental Disease Research Center, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Kwang-Sun Kim
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan, 46241, Republic of Korea.
| | - Yong Rok Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
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Schneewind O, Missiakas DM. Staphylococcal Protein Secretion and Envelope Assembly. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0070-2019. [PMID: 31267890 PMCID: PMC7028390 DOI: 10.1128/microbiolspec.gpp3-0070-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 12/13/2022] Open
Abstract
The highly cross-linked peptidoglycan represents the rigid layer of the bacterial envelope and protects bacteria from osmotic lysis. In Gram-positive bacteria, peptidoglycan also functions as a scaffold for the immobilization of capsular polysaccharide, wall teichoic acid (WTA), and surface proteins. This chapter captures recent development on the assembly of the envelope of Staphylococcus aureus including mechanisms accounting for immobilization of molecules to peptidoglycan as well as hydrolysis of peptidoglycan for the specific release of bound molecules, facilitation of protein secretion across the envelope and cell division. Peptidoglycan, WTA and capsular polysaccharide are directly synthesized onto undecaprenol. Surface proteins are anchored by Sortase A, a membrane-embedded transpeptidase that scans secreted polypeptides for the C-terminal LPXTG motif of sorting signals. The resulting acyl enzyme intermediate is resolved by lipid II, the undecaprenol-bound peptidoglycan precursor. While these pathways share membrane diffusible undecaprenol, assembly of these molecules occurs either at the cross-walls or the cell poles. In S. aureus, the cross-wall represents the site of de novo peptidoglycan synthesis which is eventually split to complete the cell cycle yielding newly divided daughter cells. Peptidoglycan synthesized at the cross-wall is initially devoid of WTA. Conversely, lipoteichoic acid (LTA) synthesis which does not require bactoprenol is seemingly restricted to septal membranes. Similarly, S. aureus distinguishes two types of surface protein precursors. Polypeptides with canonical signal peptides are deposited at the cell poles, whereas precursors with conserved YSIRK-GXXS motif signal peptides traffic to the cross-wall. A model for protein trafficking in the envelope and uneven distribution of teichoic acids is discussed.
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Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637
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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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Abstract
The chapter about the Gram-positive bacterial cell wall gives a brief historical background on the discovery of Gram-positive cell walls and their constituents and microscopic methods applied for studying the Gram-positive cell envelope. Followed by the description of the different chemical building blocks of peptidoglycan and the biosynthesis of the peptidoglycan layers and high turnover of peptidoglycan during bacterial growth. Lipoteichoic acids and wall teichoic acids are highlighted as major components of the cell wall. Characterization of capsules and the formation of extracellular vesicles by Gram-positive bacteria close the section on cell envelopes which have a high impact on bacterial pathogenesis. In addition, the specialized complex and unusual cell wall of mycobacteria is introduced thereafter. Next a short back view is given on the development of electron microscopic examinations for studying bacterial cell walls. Different electron microscopic techniques and methods applied to examine bacterial cell envelopes are discussed in the view that most of the illustrated methods should be available in a well-equipped life sciences orientated electron microscopic laboratory. In addition, newly developed and mostly well-established cryo-methods like high-pressure freezing and freeze-substitution (HPF-FS) and cryo-sections of hydrated vitrified bacteria (CEMOVIS, Cryo-electron microscopy of vitreous sections) are described. At last, modern cryo-methods like cryo-electron tomography (CET) and cryo-FIB-SEM milling (focus ion beam-scanning electron microscopy) are introduced which are available only in specialized institutions, but at present represent the best available methods and techniques to study Gram-positive cell walls under close-to-nature conditions in great detail and at high resolution.
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Affiliation(s)
- Manfred Rohde
- Helmholtz Centre for Infection Research, HZI, Central Facility for Microscopy, ZEIM, Braunschweig, Germany
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Chung M, Borges V, Gomes JP, de Lencastre H, Tomasz A. Phenotypic signatures and genetic determinants of oxacillin tolerance in a laboratory mutant of Staphylococcus aureus. PLoS One 2018; 13:e0199707. [PMID: 29969476 PMCID: PMC6029783 DOI: 10.1371/journal.pone.0199707] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/12/2018] [Indexed: 11/18/2022] Open
Abstract
Addition of β-lactam antibiotics to growing cultures of bacteria inhibit synthesis of the bacterial cell wall peptidoglycan accompanied by killing (loss of viable titer) and lysis (physical disintegration) of the cells. However, it has also been well established that these antibiotics are not effective in killing non-growing or slow-growing bacteria and the mechanism of this "antibiotic tolerance" is not well understood. In this study, we report on the genetic basis and phenotypic properties of an antibiotic tolerant derivative of the methicillin susceptible S. aureus strain 27s. Cultures were exposed to "pulses" of high concentrations of oxacillin followed by outgrowth of the surviving bacteria. This procedure quickly selected for antibiotic tolerant mutants with an increased ability to survive antibiotic treatment without increase in the MIC value for the antibiotic. Such mutants also exhibited longer lag phase, decreased lysis, virtually no change in antibiotic susceptibilities, cross tolerance to D-cycloserine and vancomycin, and increase in biofilm formation in the presence of high concentrations of oxacillin. Whole genome sequencing showed that these altered properties were linked to mutations in the atl and gdpP genes.
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Affiliation(s)
- Marilyn Chung
- Laboratory of Microbiology & Infectious Diseases, The Rockefeller University, New York, New York, United States of America
| | - Vitor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisboa, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisboa, Portugal
| | - Herminia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica António Xavier (ITQB) da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Alexander Tomasz
- Laboratory of Microbiology & Infectious Diseases, The Rockefeller University, New York, New York, United States of America
- * E-mail:
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Ujimine S, Tone S, Saito M, Yamada S. Intracellular morphological changes in Staphylococcus aureus induced by treatment with sodium hypochlorite. Med Mol Morphol 2017; 50:178-184. [PMID: 28516285 DOI: 10.1007/s00795-017-0159-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/08/2017] [Indexed: 12/15/2022]
Abstract
Sodium hypochlorite (NaOCl) is commonly used as a disinfectant; however, its bactericidal mechanism has not yet been clarified. In the present study, the bactericidal mechanism of NaOCl was examined using microscopy and gel electrophoresis techniques with Staphylococcus aureus strain 209P. S. aureus cells treated with 500 and 1000 ppm NaOCl for 5 and 15 min were observed by SEM and TEM. SEM images of the bacterial cells treated with NaOCl showed an irregular surface, with cells being partially invaginated. TEM images of the bacterial cells showed cytoplasmic alterations, accompanied by a partially irregular cellular surface. Under a fluorescence microscope, we clearly observed fluorescence quenching in the 1000 ppm NaOCl-treated cells. Based on these observations, which indicated that NaOCl damaged chromosomal DNA, we next extracted chromosomal DNA from bacterial cells treated with NaOCl and performed agarose gel electrophoresis. Chromosomal DNA was absent in the DNA sample from the bacterial cells treated with 500 ppm NaOCl. From these biochemical results, it was strongly suggested that NaOCl degrades the chromosomal DNA of S. aureus. We consider that the morphological changes in the cytoplasm induced by NaOCl may be related to NaOCl-induced degradation of S. aureus chromosomal DNA.
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Affiliation(s)
- Shiori Ujimine
- Department of Health Science, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama, 701-0193, Japan.
| | - Shigenobu Tone
- Graduate School of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama, 350-0394, Japan
| | - Mineki Saito
- Department of Microbiology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Sakuo Yamada
- Department of Health Science, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama, 701-0193, Japan
- Department of Microbiology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
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Dual Targeting of Cell Wall Precursors by Teixobactin Leads to Cell Lysis. Antimicrob Agents Chemother 2016; 60:6510-6517. [PMID: 27550357 DOI: 10.1128/aac.01050-16] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/06/2016] [Indexed: 01/29/2023] Open
Abstract
Teixobactin represents the first member of a newly discovered class of antibiotics that act through inhibition of cell wall synthesis. Teixobactin binds multiple bactoprenol-coupled cell wall precursors, inhibiting both peptidoglycan and teichoic acid synthesis. Here, we show that the impressive bactericidal activity of teixobactin is due to the synergistic inhibition of both targets, resulting in cell wall damage, delocalization of autolysins, and subsequent cell lysis. We also find that teixobactin does not bind mature peptidoglycan, further increasing its activity at high cell densities and against vancomycin-intermediate Staphylococcus aureus (VISA) isolates with thickened peptidoglycan layers. These findings add to the attractiveness of teixobactin as a potential therapeutic agent for the treatment of infection caused by antibiotic-resistant Gram-positive pathogens.
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Loss of Antibiotic Tolerance in Sod-Deficient Mutants Is Dependent on the Energy Source and Arginine Catabolism in Enterococci. J Bacteriol 2015; 197:3283-93. [PMID: 26260456 DOI: 10.1128/jb.00389-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/31/2015] [Indexed: 01/25/2023] Open
Abstract
UNLABELLED Enterococci are naturally tolerant to typically bactericidal cell wall-active antibiotics, meaning that their growth is inhibited but they are not killed even when exposed to a high concentration of the drug. The molecular reasons for this extraordinary tolerance are still incompletely understood. Previous work showed that resistance to killing collapsed specifically in mutants affected in superoxide dismutase (Sod) activity, arguing that bactericidal antibiotic treatment led to induction of a superoxide burst. In the present work, we show that loss of antibiotic tolerance in ΔsodA mutants of pathogenic enterococci is dependent on the energy source present during antibiotic treatment. Hexoses induce greater killing than the pentose ribose, and no killing was observed with glycerol as the energy source. These results point to glycolytic reactions as crucial for antibiotic-mediated killing of ΔsodA mutants. A transposon mutant library was constructed in Enterococcus faecalis ΔsodA mutants and screened for restored tolerance of vancomycin. Partially restored tolerance was observed in mutants with transposon integrations into intergenic regions upstream of regulators implicated in arginine catabolism. In these mutants, the arginine deiminase operon was highly upregulated. A model for the action of cell wall-active antibiotics in tolerant and nontolerant bacteria is proposed. IMPORTANCE Antibiotic tolerance is a serious clinical concern, since tolerant bacteria have considerably increased abilities to resist killing by bactericidal drugs. Using enterococci as models for highly antibiotic-tolerant pathogens, we showed that tolerance of these bacteria is linked to their superoxide dismutase (Sod), arguing that bactericidal antibiotics induce generation of reactive oxygen species inside cells. Wild-type strains are tolerant because they detoxify these deleterious molecules by the activity of Sod, whereas Sod-deficient strains are killed. This study showed that killing depends on the energy source present during treatment and that an increase in arginine catabolism partially restored tolerance of the Sod mutants. These results are used to propose a mode-of-action model of cell wall-active antibiotics in tolerant and nontolerant bacteria.
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Zheng L, Yan M, Fan F, Ji Y. The Essential WalK Histidine Kinase and WalR Regulator Differentially Mediate Autolysis of Staphylococcus aureus RN4220. JOURNAL OF NATURE AND SCIENCE 2015; 1:e111. [PMID: 26052549 PMCID: PMC4457336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The two-component regulatory system, WalR/WalK is necessary for growth of different gram-positive bacteria, including Staphylococcus aureus. In present study, we confirmed the essentiality of both the histidine kinase protein WalK and the response regulator WalR for growth using S. aureus RN4220 strain and demonstrated that the histidine kinase protein WalK and the response regulator WalR function differently in regulation of staphylococcal autolysis. The down-regulation of walR expression effectively inhibited Triton X-100-induced lysis and had a weak impact on bacterial tolerance to penicillin induced cell lysis. In contrast, the down-regulation of walK expression had no influence on either Triton X-100- or penicillin-caused autolysis. Moreover, we determined the effect of WalR and WalK on bacterial hydrolase activity using a zymogram analysis. The results showed that the cell lysate of down-regulated walR expression mutant displayed several bands of decreased cell wall hydrolytic activities; however, the down-regulation of WalK had no dramatic impact on the hydrolytic activities. Furthermore, we examined the impact of WalR on the transcription of cidA associated with staphylococcal autolysis, and the results showed that the down-regulation of WalR led to decreased transcription of cidA in the log phase of growth. Taken together, the above results suggest that the essential WalR response regulator and the essential WalK histidine kinase might differently control bacterial lysis in RN4220 strain.
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Affiliation(s)
- Li Zheng
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota. 1971 Commonwealth Ave. St. Paul. MN 55108, USA
| | - Meiying Yan
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota. 1971 Commonwealth Ave. St. Paul. MN 55108, USA
| | - Frank Fan
- Promega Corporation, Madison, WI 53711, USA
| | - Yinduo Ji
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota. 1971 Commonwealth Ave. St. Paul. MN 55108, USA
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Bacteriocin protein BacL1 of Enterococcus faecalis targets cell division loci and specifically recognizes L-Ala2-cross-bridged peptidoglycan. J Bacteriol 2014; 197:286-95. [PMID: 25368300 DOI: 10.1128/jb.02203-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Bacteriocin 41 (Bac41) is produced from clinical isolates of Enterococcus faecalis and consists of two extracellular proteins, BacL1 and BacA. We previously reported that BacL1 protein (595 amino acids, 64.5 kDa) is a bacteriolytic peptidoglycan D-isoglutamyl-L-lysine endopeptidase that induces cell lysis of E. faecalis when an accessory factor, BacA, is copresent. However, the target of BacL1 remains unknown. In this study, we investigated the targeting specificity of BacL1. Fluorescence microscopy analysis using fluorescent dye-conjugated recombinant protein demonstrated that BacL1 specifically localized at the cell division-associated site, including the equatorial ring, division septum, and nascent cell wall, on the cell surface of target E. faecalis cells. This specific targeting was dependent on the triple repeat of the SH3 domain located in the region from amino acid 329 to 590 of BacL1. Repression of cell growth due to the stationary state of the growth phase or to treatment with bacteriostatic antibiotics rescued bacteria from the bacteriolytic activity of BacL1 and BacA. The static growth state also abolished the binding and targeting of BacL1 to the cell division-associated site. Furthermore, the targeting of BacL1 was detectable among Gram-positive bacteria with an L-Ala-L-Ala-cross-bridging peptidoglycan, including E. faecalis, Streptococcus pyogenes, or Streptococcus pneumoniae, but not among bacteria with alternate peptidoglycan structures, such as Enterococcus faecium, Enterococcus hirae, Staphylococcus aureus, or Listeria monocytogenes. These data suggest that BacL1 specifically targets the L-Ala-L-Ala-cross-bridged peptidoglycan and potentially lyses the E. faecalis cells during cell division.
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Grilo IR, Ludovice AM, Tomasz A, de Lencastre H, Sobral RG. The glucosaminidase domain of Atl - the major Staphylococcus aureus autolysin - has DNA-binding activity. Microbiologyopen 2014; 3:247-56. [PMID: 24585695 PMCID: PMC3996572 DOI: 10.1002/mbo3.165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/08/2014] [Accepted: 01/20/2014] [Indexed: 11/08/2022] Open
Abstract
In this communication, we describe evidence demonstrating the capacity of Atl, the major Staphylococcus aureus autolytic enzyme to bind DNA. Electrophoretic mobility shift assays (EMSA) show that both the Atl protein and the endo-β-N-acetylglucosaminidase (GL) domain were able to bind DNA of nonspecific sequence. The implications of this unexpected observation for the physiology of S. aureus remain to be explored.
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Affiliation(s)
- Inês R Grilo
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, 2780, Oeiras, Portugal
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Abstract
The cytoplasmic membrane of most bacteria is surrounded by a more or less thick murein layer (peptidoglycan) that protects the protoplast from mechanical damage, osmotic rupture and lysis. When bacteria are dividing processes are initiated stepwise that involve DNA replication, constriction of the membranes, cell growth, biosynthesis of new murein, and finally the generation of two daughter cells. As the daughter cells are still covalently interlinked by the murein network they must be separated by specific peptidoglycan hydrolases, also referred to as autolysins. In staphylococci, the major autolysin (Atl) and its processed products N-acetylmuramoyl-l-alanine amidase (AM) and endo-β-N-acetylglucosaminidase (GL) have been in the research focus for long time. This review addresses phenotypic consequences of atl mutants, impact of Atl in virulence, the mechanism of targeting to the septum region, regulation of atl, the structure of the amidase and the repeat regions, as well as the phylogeny of Atl and its use in Staphylococcus genus and species typing.
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Chen C, Krishnan V, Macon K, Manne K, Narayana SVL, Schneewind O. Secreted proteases control autolysin-mediated biofilm growth of Staphylococcus aureus. J Biol Chem 2013; 288:29440-52. [PMID: 23970550 PMCID: PMC3795244 DOI: 10.1074/jbc.m113.502039] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus epidermidis, a commensal of humans, secretes Esp protease to prevent Staphylococcus aureus biofilm formation and colonization. Blocking S. aureus colonization may reduce the incidence of invasive infectious diseases; however, the mechanism whereby Esp disrupts biofilms is unknown. We show here that Esp cleaves autolysin (Atl)-derived murein hydrolases and prevents staphylococcal release of DNA, which serves as extracellular matrix in biofilms. The three-dimensional structure of Esp was revealed by x-ray crystallography and shown to be highly similar to that of S. aureus V8 (SspA). Both atl and sspA are necessary for biofilm formation, and purified SspA cleaves Atl-derived murein hydrolases. Thus, S. aureus biofilms are formed via the controlled secretion and proteolysis of autolysin, and this developmental program appears to be perturbed by the Esp protease of S. epidermidis.
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Affiliation(s)
- Chen Chen
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637
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16
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Hyo Y, Yamada S, Fukutsuji K, Harada T. Thickening of the cell wall in macrolide-resistant Staphylococcus aureus. Med Mol Morphol 2013; 46:217-24. [PMID: 23408211 DOI: 10.1007/s00795-013-0027-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 11/21/2012] [Indexed: 10/27/2022]
Abstract
Macrolides are widely used at low dosage for long-term therapy of chronic sinusitis. Twenty clinical macrolide-resistant Staphylococcus aureus strains were morphologically compared with 10 clinical macrolide-sensitive strains. PCR amplification was performed to determine the presence of four known macrolide resistance genes. Transmission electron microscopy revealed significantly thicker cell walls in clinical macrolide-resistant strains. Even though the ultrastructural characteristics were shared by all macrolide-resistant strains, they were not associated with the presence or absence of the known macrolide-resistance genes. We also demonstrated that macrolide-resistant mutant strains derived in vitro from a macrolide-sensitive parent strain had thickened cell walls and did not harbor the known macrolide-resistance genes. These results, therefore, revealed that macrolide-resistant S. aureus strains have thickened cell walls as a common ultrastructural characteristic and that cell wall thickening is likely mediated by an unknown gene which is unrelated to any known macrolide resistance gene.
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Affiliation(s)
- Yukiyoshi Hyo
- Department of Otolaryngology, Kawasaki Medical School, 577 Matsusima, Kurasiki, Okayama, 701-0192, Japan,
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17
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Antimicrobial effects of Burow's solution on Staphylococcus aureus and Pseudomonas aeruginosa. Med Mol Morphol 2012; 45:66-71. [PMID: 22718290 DOI: 10.1007/s00795-011-0540-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 02/08/2011] [Indexed: 10/28/2022]
Abstract
Burow's solution has been shown to be effective against chronic suppurative otitis media and otitis externa. We demonstrated that Burow's solution had antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa, inducing ultrastructural changes in these bacteria in vitro. S. aureus strain 209P and P. aeruginosa strain IID1130 were treated with 13% Burow's solution. Viable cell counts were determined to measure bactericidal effects. Ultrastructural changes in cells of both strains were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Viable cell counting revealed that S. aureus cells treated with Burow's solution were killed within 30 min. The viable cell count of P. aeruginosa was reduced by 1 × 10(7) colony-forming units/ml (CFU/ml) after a 60-min treatment. SEM examination of S. aureus revealed blebbing on the surface of bacterial cells, whereas TEM revealed undulating deformation of the bacterial cell wall, diluted cytoplasm, and cell membrane detachment. SEM observations of P. aeruginosa revealed a more apparent undulating deformation of the bacterial cell surface. TEM observations also revealed deformations in the bacterial cell wall and diluted cytoplasm in both bacteria. These findings show that Burow's solution is active against S. aureus and P. aeruginosa, resulting in damage to the cell wall.
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Lama A, Pané-Farré J, Chon T, Wiersma AM, Sit CS, Vederas JC, Hecker M, Nakano MM. Response of methicillin-resistant Staphylococcus aureus to amicoumacin A. PLoS One 2012; 7:e34037. [PMID: 22479511 PMCID: PMC3316591 DOI: 10.1371/journal.pone.0034037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 02/21/2012] [Indexed: 11/18/2022] Open
Abstract
Amicoumacin A exhibits strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), hence we sought to uncover its mechanism of action. Genome-wide transcriptome analysis of S. aureus COL in response to amicoumacin A showed alteration in transcription of genes specifying several cellular processes including cell envelope turnover, cross-membrane transport, virulence, metabolism, and general stress response. The most highly induced gene was lrgA, encoding an antiholin-like product, which is induced in cells undergoing a collapse of Δψ. Consistent with the notion that LrgA modulates murein hydrolase activity, COL grown in the presence of amicoumacin A showed reduced autolysis, which was primarily caused by lower hydrolase activity. To gain further insight into the mechanism of action of amicoumacin A, a whole genome comparison of wild-type COL and amicoumacin A-resistant mutants isolated by a serial passage method was carried out. Single point mutations generating codon substitutions were uncovered in ksgA (encoding RNA dimethyltransferase), fusA (elongation factor G), dnaG (primase), lacD (tagatose 1,6-bisphosphate aldolase), and SACOL0611 (a putative glycosyl transferase). The codon substitutions in EF-G that cause amicoumacin A resistance and fusidic acid resistance reside in separate domains and do not bring about cross resistance. Taken together, these results suggest that amicoumacin A might cause perturbation of the cell membrane and lead to energy dissipation. Decreased rates of cellular metabolism including protein synthesis and DNA replication in resistant strains might allow cells to compensate for membrane dysfunction and thus increase cell survivability.
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Affiliation(s)
- Amrita Lama
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Jan Pané-Farré
- Institute for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Tai Chon
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Anna M. Wiersma
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Clarissa S. Sit
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - John C. Vederas
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael Hecker
- Institute for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Michiko M. Nakano
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Beaverton, Oregon, United States of America
- * E-mail:
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19
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Frankel MB, Hendrickx APA, Missiakas DM, Schneewind O. LytN, a murein hydrolase in the cross-wall compartment of Staphylococcus aureus, is involved in proper bacterial growth and envelope assembly. J Biol Chem 2011; 286:32593-605. [PMID: 21784864 PMCID: PMC3173183 DOI: 10.1074/jbc.m111.258863] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 07/20/2011] [Indexed: 02/02/2023] Open
Abstract
Cell cycle progression for the spherical microbe Staphylococcus aureus requires the coordinated synthesis and remodeling of peptidoglycan. The majority of these rearrangements takes place at the mid-cell, in a compartment designated the cross-wall. Secreted polypeptides endowed with a YSIRK-G/S signal peptide are directly delivered to the cross-wall compartment. One such YSIRK-containing protein is the murein hydrolase LytN. lytN mutations precipitate structural damage to the cross-wall and interfere with staphylococcal growth. Overexpression of lytN also affects growth and triggers rupture of the cross-wall. The lytN phenotype can be reversed by the controlled expression of lytN but not by adding purified LytN to staphylococcal cultures. LytN harbors LysM and CHAP domains, the latter of which functions as both an N-acetylmuramoyl-L-alanine amidase and D-alanyl-glycine endopeptidase. Thus, LytN secretion into the cross-wall promotes peptidoglycan separation and completion of the staphylococcal cell cycle.
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Affiliation(s)
- Matthew B. Frankel
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637
| | | | | | - Olaf Schneewind
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637
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20
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Sianglum W, Srimanote P, Wonglumsom W, Kittiniyom K, Voravuthikunchai SP. Proteome analyses of cellular proteins in methicillin-resistant Staphylococcus aureus treated with rhodomyrtone, a novel antibiotic candidate. PLoS One 2011; 6:e16628. [PMID: 21326597 PMCID: PMC3033880 DOI: 10.1371/journal.pone.0016628] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 01/05/2011] [Indexed: 11/19/2022] Open
Abstract
The ethanolic extract from Rhodomyrtus tomentosa leaf exhibited good antibacterial activities against both methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus ATCC 29213. Its minimal inhibitory concentration (MIC) values ranged from 31.25–62.5 µg/ml, and the minimal bactericidal concentration (MBC) was 250 µg/ml. Rhodomyrtone, an acylphloroglucinol derivative, was 62.5–125 times more potent at inhibiting the bacteria than the ethanolic extract, the MIC and MBC values were 0.5 µg/ml and 2 µg/ml, respectively. To provide insights into antibacterial mechanisms involved, the effects of rhodomyrtone on cellular protein expression of MRSA have been investigated using proteomic approaches. Proteome analyses revealed that rhodomyrtone at subinhibitory concentration (0.174 µg/ml) affected the expression of several major functional classes of whole cell proteins in MRSA. The identified proteins involve in cell wall biosynthesis and cell division, protein degradation, stress response and oxidative stress, cell surface antigen and virulence factor, and various metabolic pathways such as amino acid, carbohydrate, energy, lipid, and nucleotide metabolism. Transmission electron micrographs confirmed the effects of rhodomyrtone on morphological and ultrastructural alterations in the treated bacterial cells. Biological processes in cell wall biosynthesis and cell division were interrupted. Prominent changes including alterations in cell wall, abnormal septum formation, cellular disintegration, and cell lysis were observed. Unusual size and shape of staphylococcal cells were obviously noted in the treated MRSA. These pioneer findings on proteomic profiling and phenotypic features of rhodomyrtone-treated MRSA may resolve its antimicrobial mechanisms which could lead to the development of a new effective regimen for the treatment of MRSA infections.
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Affiliation(s)
- Wipawadee Sianglum
- Department of Microbiology and Natural Products Research Center, Faculty of Science, Prince of Songkla University, Songkla, Thailand
| | - Potjanee Srimanote
- Graduate Study, Faculty of Allied Health Sciences, Thammasat University, Pathumtanee, Thailand
| | - Wijit Wonglumsom
- Department of Clinical Microbiology, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Kanokwan Kittiniyom
- Department of Clinical Microbiology, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Supayang P. Voravuthikunchai
- Department of Microbiology and Natural Products Research Center, Faculty of Science, Prince of Songkla University, Songkla, Thailand
- * E-mail:
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21
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Yu X, Zheng L, Yang J, Lei T, Ji Y. Characterization of essential enolase in Staphylococcus aureus. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0532-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Ueta M, Wada C, Wada A. Formation of 100S ribosomes in Staphylococcus aureus by the hibernation promoting factor homolog SaHPF. Genes Cells 2009; 15:43-58. [PMID: 20015224 DOI: 10.1111/j.1365-2443.2009.01364.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In the stationary growth phase of Escherichia coli, the 70S ribosomes are dimerized by the ribosome modulation factor (RMF) and hibernation promoting factor (HPF) proteins to form 100S ribosomes, which lose translational activity. In this study we found 100S ribosomes in the gram-positive bacterium Staphylococcus aureus, which has an HPF homolog (named SaHPF) but no RMF homolog. Unlike in E. coli, 100S ribosomes exist in all growth phases of S. aureus, with the highest levels at the transition from the exponential phase to the stationary phase. To find the key factors involved in 100S formation, we analyzed proteins associated with crude ribosomes using radical-free and highly reducing 2-D PAGE and MALDI TOF/MS. Only the SaHPF levels changed in parallel with the changes in 100S levels. SaHPF bound preferentially to 70S components in 100S ribosomes, with a molar ratio of 1 : 1 relative to the 70S, but some SaHPF was also detected in free 70S ribosomes. High-salt washing of the crude ribosomes released SaHPF and dissociated the 100S ribosomes to their 70S components. When these 70S components were incubated with purified SaHPF in vitro, they re-associated to form 100S. These results suggest that SaHPF is a key protein involved in 100S ribosome formation in S. aureus.
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Affiliation(s)
- Masami Ueta
- Yoshida Biological Laboratory, 11-1, Takehanasotoda-cho, Yamashina-ku, Kyoto 607-8081, Japan
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23
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Kawai M, Yamagishi JI. Mechanisms of action of acriflavine: electron microscopic study of cell wall changes induced in Staphylococcus aureus by acriflavine. Microbiol Immunol 2009; 53:481-6. [PMID: 19703241 DOI: 10.1111/j.1348-0421.2009.00151.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The antimicrobial action of acriflavine, a quaternary ammonium compound, on Staphylococcus aureus was studied by electron microscopic observation. The bactericidal activity of acriflavine was dose-dependent over the 4 hr of exposure time. Scanning electron micrographs showed a wavy wrinkled cell surface following treatment with acriflavine. Transmission electron micrographs showed thickened cell walls following treatment with acriflavine. Acriflavine-induced cell wall thickness seemed to affect both the peripheral and cross walls, but was reversible after treatment removal. These findings indicate that cell wall thickness is a characteristic phenotype of S. aureus exposed to acriflavine. It is therefore believed that cell wall thickness plays an important role in the mechanism of action of acriflavine.
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Affiliation(s)
- Mako Kawai
- Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji, Hyogo
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24
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Trotonda MP, Xiong YQ, Memmi G, Bayer AS, Cheung AL. Role of mgrA and sarA in methicillin-resistant Staphylococcus aureus autolysis and resistance to cell wall-active antibiotics. J Infect Dis 2009; 199:209-18. [PMID: 19072553 DOI: 10.1086/595740] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND We have previously shown the importance of mgrA and sarA in controlling autolysis of Staphylococcus aureus, with MgrA and SarA both being negative regulators of murein hydrolases. METHODS In this study, we analyzed the effects of mgrA and sarA on antibiotic-mediated lysis in vitro and on the responses to cell wall-active antibiotic therapy in an experimental endocarditis model by use of 2 representative MRSA strains: the laboratory strain COL and the community-acquired clinical strain MW2. RESULTS We found that mgrA and sarA independently down-regulated sarV (a marker for autolysis), although the alteration in sarV expression did not correlate directly with the autolysis profiles of single mgrA and sarA mutants. Importantly, the mgrA/sarA double mutants of both strains were more autolytic than the single mutants in vitro. We demonstrated that, despite equivalent intrinsic virulences of the parent strains and their isogenic mgrA/sarA double mutants in the endocarditis model, oxacillin and vancomycin treatment of the mgrA/sarA double mutants yielded significant reductions in vegetation bacterial densities in vivo, compared with treatment of their respective parent strains. CONCLUSIONS These results suggest that down-regulation of mgrA/sarA in combination with use of cell wall-active antibiotics may represent a novel approach to treat MRSA infections.
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Affiliation(s)
- María Pilar Trotonda
- Department of Microbiology, Dartmouth Medical School, Hanover, New Hampshire, USA
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25
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Hyo Y, Yamada S, Harada T. Characteristic cell wall ultrastructure of a macrolide-resistant Staphylococcus capitis strain isolated from a patient with chronic sinusitis. Med Mol Morphol 2008; 41:160-4. [PMID: 18807142 DOI: 10.1007/s00795-008-0409-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 06/02/2008] [Indexed: 10/21/2022]
Abstract
Fourteen-membered-ring macrolides have an antiinflammatory effect, in addition to their antibacterial effect, and are widely used at low dosages for long-term therapy for chronic inflammatory disease such as diffuse pan-bronchiolitis and chronic sinusitis. A macrolide-resistant coagulase-negative staphylococcal strain was obtained from the maxillary sinus of a patient with chronic sinusitis, who failed long-term macrolide therapy. The isolated strain was characterized as Staphylococcus capitis and had an MIC for erythromycin greater than 128 microg/ml. Morphological observation demonstrated that this macrolide-resistant S. capitis strain had a thicker cell wall than macrolide-sensitive S. capitis strains. Moreover, the strain was not carrying any other than the four genes that are known mainly to encode for macrolide resistance in S. aureus. Therefore, the strain had an unknown macrolide-resistance mechanism that might be related to cell wall thickening.
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Affiliation(s)
- Yukiyoshi Hyo
- Department of Otolaryngology, Kawasaki Medical School, 577 Matsusima, Kurasiki, Okayama, Japan.
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26
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Antignac A, Sieradzki K, Tomasz A. Perturbation of cell wall synthesis suppresses autolysis in Staphylococcus aureus: evidence for coregulation of cell wall synthetic and hydrolytic enzymes. J Bacteriol 2007; 189:7573-80. [PMID: 17827298 PMCID: PMC2168716 DOI: 10.1128/jb.01048-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial peptidoglycan hydrolases are considered to have destructive potential, which in the presence of inhibitory concentrations of cell wall synthesis inhibitors is involved in cell lysis. Therefore, the expression and activity of autolytic enzymes must be tightly regulated in growing cells. We describe here a series of experiments undertaken to examine further the coordination between cell wall synthesis and degradation. Cell growth in the presence of subinhibitory concentrations of beta-lactam antibiotics was used to determine the effects of the partial inhibition of cell wall synthesis on the status of the autolytic system in Staphylococcus aureus. Our results revealed that, despite increased in vitro hydrolysis of cell walls by autolytic enzymes due to hypo-cross-linked peptidoglycans, cells grown in the presence of beta-lactams were dramatically less prone to autolysis as a result of decreased transcription and enzymatic activities of several major autolytic enzymes. Similar repression of autolytic enzymatic activity and transcription was also observed when cell wall synthesis was disturbed by lowering the level of transcription of pbpB, the gene encoding the major transpeptidase in S. aureus. Our data show that the perturbation of cell wall synthesis in growing cells of S. aureus induces strong repression of the autolytic system and provide evidence for transcriptional regulation between cell wall synthetic and hydrolytic enzymes.
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Affiliation(s)
- Aude Antignac
- Laboratory of Microbiology, The Rockefeller University, 1230 York Ave., New York, NY 10021, USA
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27
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Matias VRF, Beveridge TJ. Cryo-electron microscopy of cell division in Staphylococcus aureus reveals a mid-zone between nascent cross walls. Mol Microbiol 2007; 64:195-206. [PMID: 17376082 DOI: 10.1111/j.1365-2958.2007.05634.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cryo-electron microscopy of frozen-hydrated thin sections permits the observation of the real distribution of mass in biological specimens allowing the native structure of bacteria to be seen, including the natural orientation of their surface layers. Here, we use this approach to study the fine ultrastructure of the division site, or septum, of Staphylococcus aureus D(2)C. Frozen-hydrated sections revealed a differentiated cell wall at the septum, showing two high-density regions sandwiched between three low-density zones. The two zones adjacent to the membrane appeared as an extension of the periplasmic space seen in this organism's cell envelope and showed no distinguishing structures within them. Immediately next to these were higher-density zones that corresponded to nascent cross walls of the septum. Unexpectedly, a rather broad low-density zone was seen separating cross walls in the septum. This mid-zone of low density appeared inflated and without visible structures in isolated cell walls, which showed only the high-density zones of the septum. Here, we suggest that frozen-hydrated thin sections have captured a highly fragile septal region, the mid-zone, which results from the dynamic action of autolysis and actively separates daughter cells during division. The two zones next to the membranes are periplasmic spaces. Immediately next to these are the growing cross walls composed of peptidoglycan, teichoic acid and protein.
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Affiliation(s)
- Valério R F Matias
- Department of Molecular and Cellular Biology College of Biological Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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28
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Yamada S, Hyo Y, Ohmori S, Ohuchi M. Role of ciprofloxacin in its synergistic effect with fosfomycin on drug-resistant strains of Pseudomonas aeruginosa. Chemotherapy 2007; 53:202-9. [PMID: 17356268 DOI: 10.1159/000100811] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 04/21/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND The aim of this study was to investigate the synergistic effect of ciprofloxacin (CPFX) and fosfomycin (FOM) on CPFX-resistant Pseudomonas aeruginosa strains. METHODS The synergistic effect was evaluated using the fractional inhibitory concentration index, acute bactericidal effect and morphological observation. RESULTS In the fractional inhibitory concentration index experiments, the combination of CPFX with FOM showed a synergistic effect in 20 of 74 (27.0%) strains of P. aeruginosa. From the morphological observations, it was determined that CPFX affected the outer membrane structure. CPFX combined with FOM caused striking morphological changes, resulting in bacteriolysis. A time lag experiment suggested that the addition of CPFX prior to FOM produced more pronounced bactericidal activity than the addition of FOM prior to CPFX. CONCLUSIONS These results indicate that the combination of CPFX with FOM induces a synergistic effect on CPFX-resistant P. aeruginosa strains. The role of CPFX is thought to be related to damage of the outer membrane, enhancing FOM penetration.
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Affiliation(s)
- Sakuo Yamada
- Department of Microbiology, Kawasaki Medical School, Okayama, Japan
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29
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Zheng L, Yu C, Bayles K, Lasa I, Ji Y. Conditional mutation of an essential putative glycoprotease eliminates autolysis in Staphylococcus aureus. J Bacteriol 2007; 189:2734-42. [PMID: 17237169 PMCID: PMC1855823 DOI: 10.1128/jb.01806-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our previous studies demonstrated that a putative Staphylococcus aureus glycoprotease (Gcp) is essential for bacterial survival, indicating that Gcp may be a novel target for developing antibacterial agents. However, the biological function of Gcp is unclear. In order to elucidate the reason that Gcp is required for growth, we examined the role of Gcp in bacterial autolysis, which is an important biological process for bacterial growth. Using both a spacp-regulated gcp expression strain and a TetR-regulated gcp antisense expression strain, we found that the down-regulation of gcp expression can effectively inhibit Triton X-100-induced lysis, eliminate penicillin- and vancomycin-caused cell lysis, and dramatically increase tolerance to hydrolases. Moreover, we determined whether resistance to lysis is due to a defect in murein hydrolase activity by using a zymogram analysis. The results showed that the cell lysate of a down-regulated gcp expression mutant displayed several bands of decreased murein hydrolytic activity. Furthermore, we explored the potential mechanism of Gcp's involvement in autolysis and demonstrated that Gcp may function independently from several key autolysins (Atl, LytM, and LytN) and regulators (ArlRS, Mgr/Rat, and CidA). Taken together, the above results indicate that the essential Gcp is involved in the modification of substrates of murein hydrolases as well as in the regulation of expression and/or activity of some murein hydrolases, which, in turn, may play important roles in bacterial viability.
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Affiliation(s)
- Li Zheng
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1971 Commonwealth Ave., St. Paul, MN 55108, USA
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30
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Renzoni A, Barras C, François P, Charbonnier Y, Huggler E, Garzoni C, Kelley WL, Majcherczyk P, Schrenzel J, Lew DP, Vaudaux P. Transcriptomic and functional analysis of an autolysis-deficient, teicoplanin-resistant derivative of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2006; 50:3048-61. [PMID: 16940101 PMCID: PMC1563528 DOI: 10.1128/aac.00113-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The molecular basis of glycopeptide-intermediate S. aureus (GISA) isolates is not well defined though frequently involves phenotypes such as thickened cell walls and decreased autolysis. We have exploited an isogenic pair of teicoplanin-susceptible (strain MRGR3) and teicoplanin-resistant (strain 14-4) methicillin-resistant S. aureus strains for detailed transcriptomic profiling and analysis of altered autolytic properties. Strain 14-4 displayed markedly deficient Triton X-100-triggered autolysis compared to its teicoplanin-susceptible parent, although microarray analysis paradoxically did not reveal significant reductions in expression levels of major autolytic genes atl, lytM, and lytN, except for sle1, which showed a slight decrease. The most important paradox was a more-than-twofold increase in expression of the cidABC operon in 14-4 compared to MRGR3, which was correlated with decreased expression of autolysis negative regulators lytSR and lrgAB. In contrast, the autolysis-deficient phenotype of 14-4 was correlated with both increased expression of negative autolysis regulators (arlRS, mgrA, and sarA) and decreased expression of positive regulators (agr RNAII and RNAIII). Quantitative bacteriolytic assays and zymographic analysis of concentrated culture supernatants showed a striking reduction in Atl-derived, extracellular bacteriolytic hydrolase activities in 14-4 compared to MRGR3. This observed difference was independent of the source of cell wall substrate (MRGR3 or 14-4) used for analysis. Collectively, our results suggest that altered autolytic properties in 14-4 are apparently not driven by significant changes in the transcription of key autolytic effectors. Instead, our analysis points to alternate regulatory mechanisms that impact autolysis effectors which may include changes in posttranscriptional processing or export.
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Affiliation(s)
- Adriana Renzoni
- Service of Infectious Diseases, University Hospitals of Geneva, CH-1211 Geneva 14, Switzerland
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Biswas R, Voggu L, Simon UK, Hentschel P, Thumm G, Götz F. Activity of the major staphylococcal autolysin Atl. FEMS Microbiol Lett 2006; 259:260-8. [PMID: 16734789 DOI: 10.1111/j.1574-6968.2006.00281.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The major autolysin of Staphylococcus aureus (AtlA) and of Staphylococcus epidermidis (AtlE) are well-studied enzymes. Here we created an atlA deletion mutant in S. aureus that formed large cell clusters and was biofilm-negative. In electron micrographs, the mutant cells were distinguished by rough outer cell surface. The mutant could be complemented using the atlE gene from S. epidermidis. To study the role of the repetitive sequences of atlE, we expressed in Escherichia coli the amidase domain encoded by the gene, carrying no repeat regions (amiE) or two repeat regions (amiE-R1,2), or the three repeat regions alone (R1,2,3) as N-terminal His-tag fusion proteins. Only slight differences in the cell wall lytic activity between AmiE and AmiE-R1,2 were observed. The repetitive sequences exhibit a good binding affinity to isolated peptidoglycan and might contribute to the targeting of the amidase to the substrate. AmiE and AmiE-R1,2 have a broad substrate specificity as shown by similar activities with peptidoglycan lacking wall teichoic acid, O-acetylation, or both. As the amidase activity of AtlA and AtlE has not been proved biochemically, we used purified AmiE-R1,2 to determine the exact peptidoglycan cleavage site. We provide the first evidence that the amidase indeed cleaves the amide bond between N-acetyl muramic acid and L-alanine.
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Affiliation(s)
- Raja Biswas
- Microbial Genetics, Universität Tübingen, Tübingen, Germany
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Kajimura J, Fujiwara T, Yamada S, Suzawa Y, Nishida T, Oyamada Y, Hayashi I, Yamagishi JI, Komatsuzawa H, Sugai M. Identification and molecular characterization of anN-acetylmuramyl-l-alanine amidase Sle1 involved in cell separation ofStaphylococcus aureus. Mol Microbiol 2005; 58:1087-101. [PMID: 16262792 DOI: 10.1111/j.1365-2958.2005.04881.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We purified a peptidoglycan hydrolase involved in cell separation from a Staphylococcus aureus atl null mutant and identified its gene. Characterization of the gene product shows a 32 kDa N-acetylmuramyl-L-alanine amidase that we designated Sle1. Analysis of peptidoglycan digests showed Sle1 preferentially cleaved N-acetylmuramyl-L-Ala bonds in dimeric cross-bridges that interlink the two murein strands in the peptidoglycan. An insertion mutation of sle1 impaired cell separation and induced S. aureus to form clusters suggesting Sle1 is involved in cell separation of S. aureus. The Sle1 mutant revealed a significant decrease in pathogenesis using an acute infection mouse model. Atl is the major autolysin of S. aureus, which has been implicated in cell separation of S. aureus. Generation of an atl/sle1 double mutant revealed that the mutant cell separation was heavily impaired suggesting that S. aureus uses two peptidoglycan hydrolases, Atl and Sle1, for cell separation. Unlike Atl, Sle1 is not directly involved in autolysis of S. aureus.
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Affiliation(s)
- Junko Kajimura
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi Hiroshima City, Hiroshima 734-8553, Japan
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Korsak D, Liebscher S, Vollmer W. Susceptibility to antibiotics and beta-lactamase induction in murein hydrolase mutants of Escherichia coli. Antimicrob Agents Chemother 2005; 49:1404-9. [PMID: 15793119 PMCID: PMC1068617 DOI: 10.1128/aac.49.4.1404-1409.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antibiotic susceptibilities and capabilities to induce beta-lactamases were studied in multiple Escherichia coli murein (peptidoglycan) hydrolase mutants. E. coli mutants lacking either three amidases, three amidases and one lytic transglycosylase, or six lytic transglycosylases showed higher levels of susceptibility to bacitracin, erythromycin, gallidermin, and vancomycin than the wild type. Mutant cells without three amidases lost viability in the presence of vancomycin and gallidermin, whereas the wild type was resistant to both antibiotics. Beta-lactamase induction was studied after introduction of a plasmid carrying the ampC and ampR genes. Upon addition of cefoxitin to the growth medium, the wild type as well as a mutant lacking all known amidases and DD-endopeptidases induced beta-lactamase, whereas a mutant lacking all known lytic transglycosylases was unable to induce beta-lactamase, showing that lytic transglycosylase activity is essential for beta-lactamase induction. Consequently, cells lacking lytic transglycosylase activity lysed in the presence of penicillin, despite the presence of the inducible beta-lactamase system. We discuss the potential of murein hydrolase inhibitors for antibiotic therapy.
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Affiliation(s)
- Dorota Korsak
- Institute of Microbiology, Faculty of Biology, Warsaw University, Poland
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Fisher JF, Meroueh SO, Mobashery S. Bacterial resistance to beta-lactam antibiotics: compelling opportunism, compelling opportunity. Chem Rev 2005; 105:395-424. [PMID: 15700950 DOI: 10.1021/cr030102i] [Citation(s) in RCA: 684] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Ogino H, Wachi M, Ishii A, Iwai N, Nishida T, Yamada S, Nagai K, Sugai M. FtsZ-dependent localization of GroEL protein at possible division sites. Genes Cells 2004; 9:765-71. [PMID: 15330853 DOI: 10.1111/j.1365-2443.2004.00770.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
When Escherichia coli is treated with penicillin, the envelopes bulge at the centre of the cells and the cells then lyse. The bulges expand into vesicle-like structures termed penicillin-induced vesicles. We have developed a method to isolate these structures and have shown that they contain mainly membrane proteins plus a high concentration of a 60 kDa protein. The N-terminal amino acid sequence of the protein is identical to that of GroEL protein. Western blotting analysis using anti-GroEL antibody showed that GroEL is indeed concentrated in the vesicles. Indirect immuno-fluorescence microscopy showed that GroEL protein is localized at the centre of the cells at the site of formation of FtsZ-rings. Localization of GroEL is dependent on FtsZ but not other Fts proteins. GroEL mutants formed elongated cells having no or asymmetrically localized FtsZ-rings at the restrictive temperature. These findings suggest a possible role of the GroEL protein in cell division.
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Affiliation(s)
- Hidetaka Ogino
- Department of Bioengineering, Tokyo Institute of Technology, 4259-B-38 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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36
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Touhami A, Jericho MH, Beveridge TJ. Atomic force microscopy of cell growth and division in Staphylococcus aureus. J Bacteriol 2004; 186:3286-95. [PMID: 15150213 PMCID: PMC415778 DOI: 10.1128/jb.186.11.3286-3295.2004] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The growth and division of Staphylococcus aureus was monitored by atomic force microscopy (AFM) and thin-section transmission electron microscopy (TEM). A good correlation of the structural events of division was found using the two microscopies, and AFM was able to provide new additional information. AFM was performed under water, ensuring that all structures were in the hydrated condition. Sequential images on the same structure revealed progressive changes to surfaces, suggesting the cells were growing while images were being taken. Using AFM small depressions were seen around the septal annulus at the onset of division that could be attributed to so-called murosomes (Giesbrecht et al., Arch. Microbiol. 141:315-324, 1985). The new cell wall formed from the cross wall (i.e., completed septum) after cell separation and possessed concentric surface rings and a central depression; these structures could be correlated to a midline of reactive material in the developing septum that was seen by TEM. The older wall, that which was not derived from a newly formed cross wall, was partitioned into two different surface zones, smooth and gel-like zones, with different adhesive properties that could be attributed to cell wall turnover. The new and old wall topographies are equated to possible peptidoglycan arrangements, but no conclusion can be made regarding the planar or scaffolding models.
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Affiliation(s)
- Ahmed Touhami
- Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5
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Rohrer S, Maki H, Berger-Bächi B. What makes resistance to methicillin heterogeneous? J Med Microbiol 2003; 52:605-607. [PMID: 12867551 DOI: 10.1099/jmm.0.05176-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Susanne Rohrer
- University of Zürich, Institute of Medical Microbiology, Gloriastr. 32, CH-8028 Zürich, Switzerland
| | - Hideki Maki
- University of Zürich, Institute of Medical Microbiology, Gloriastr. 32, CH-8028 Zürich, Switzerland
| | - Brigitte Berger-Bächi
- University of Zürich, Institute of Medical Microbiology, Gloriastr. 32, CH-8028 Zürich, Switzerland
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Ingavale SS, Van Wamel W, Cheung AL. Characterization of RAT, an autolysis regulator in Staphylococcus aureus. Mol Microbiol 2003; 48:1451-66. [PMID: 12791130 DOI: 10.1046/j.1365-2958.2003.03503.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In trying to identify genetic loci involved in the regulation of cap5 genes in Staphylococcus aureus, we isolated a transposon mutant that exhibited a growth defect, enhanced autolysis and increased sensitivity to Triton X-100 and penicillin, attributable in part to increased murein hydrolase activity. Analysis of the chromosomal sequence flanking the transposon insertion site revealed that the gene disrupted in the mutant encodes an open reading frame of 147 amino acids. We named this gene rat, which stands for regulator of autolytic activity. Sequence analysis indicated that Rat is homologous to the MarR and, to a lesser extent, the SarA protein families. Mutations in rat resulted in decreased expression of known autolytic regulators lytSR, lrgAB and arlRS. Gel shift studies indicated that Rat binds to the lytRS and arlRS promoters, thus confirming Rat as a DNA-binding protein to these known repressors of autolytic activity. As anticipated, rat appears to be a negative regulator of autolysin genes including lytM and lytN. These data suggest that the rat gene product is an important regulator of autolytic activity in S. aureus.
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Affiliation(s)
- S S Ingavale
- Department of Microbiology, Dartmouth Medical School, Hanover, NH 03755, USA
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Rohrer S, Berger-Bächi B. FemABX peptidyl transferases: a link between branched-chain cell wall peptide formation and beta-lactam resistance in gram-positive cocci. Antimicrob Agents Chemother 2003; 47:837-46. [PMID: 12604510 PMCID: PMC149326 DOI: 10.1128/aac.47.3.837-846.2003] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- S Rohrer
- Institute of Medical Microbiology, University of Zürich, Switzerland
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40
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Takahashi J, Komatsuzawa H, Yamada S, Nishida T, Labischinski H, Fujiwara T, Ohara M, Yamagishi JI, Sugai M. Molecular characterization of an atl null mutant of Staphylococcus aureus. Microbiol Immunol 2003; 46:601-12. [PMID: 12437027 DOI: 10.1111/j.1348-0421.2002.tb02741.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
atl is a gene encoding a bifunctional peptidoglycan hydrolase of Staphylococcus aureus. The gene product of atl is a 138 kDa protein that has an amidase domain and a glucosaminidase domain, and undergoes processing to generate two major peptidoglycan hydrolases, a 51 kDa glucosaminidase and a 62 kDa amidase in culture supernatant. An atl null mutant was isolated by allelic replacement and characterized. The mutant grew in clusters and sedimented when grown in broth culture. Analysis of peptidoglycan prepared from the wild type and the mutant revealed that there were no differences in muropeptide composition or in glycan chain length distribution. On the other hand, the atl mutation resulted in pleiotropic effects on cell surface nature. The mutant cells showed complete inhibition of metabolic turnover of cell wall peptidoglycan and revealed a rough outer cell wall surface. The mutation also decreased the amount of protein non-covalently bound to the cell surface and altered the protein profile, but did not affect proteins covalently associated with the cell wall. Lysis of growing cells treated with otherwise lytic concentration of penicillin G was completely inhibited in the mutant, but that of non-growing cells was not affected by the mutation. The atl mutation did not significantly affect the ability of S. aureus to provoke an acute infection when inoculated intraperitoneally in a mouse sepsis model. These results further support the supposition that atl gene products are involved in cell separation, cell wall turnover and penicillin-induced lysis of the cells.
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Affiliation(s)
- Junko Takahashi
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, Japan
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41
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Affiliation(s)
- A L Koch
- Department of Biology, Indiana University, 1001 E. Third St., Bloomington, IN 47405-6801, USA.
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42
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Takano M, Oshida T, Yasojima A, Yamada M, Okagaki C, Sugai M, Suginaka H, Matsushita T. Modification of autolysis by synthetic peptides derived from the presumptive binding domain of Staphylococcus aureus autolysin. Microbiol Immunol 2001; 44:463-72. [PMID: 10941929 DOI: 10.1111/j.1348-0421.2000.tb02521.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The autolytic cell wall hydrolase of Staphylococcus aureus, Atl, contains three highly cationic repeats in the central region of the amino acid sequence, and the repeats are presumed to have the role of binding the enzyme to some components on the cell surface. To explain the possible function of the repeats, we synthesized a number of 10- to 30-mer oligopeptides based on the Atl amino acid sequence (Thr432-Lys610) containing repeat 1, and examined their effects on the autolysis of S. aureus cells. When the peptides were added to a cell suspension of S. aureus under low ionic strength conditions, five peptides, A10, A11, A14, A16 and B9, showed immediate increases in optical density (OD) of the cell suspension accompanied by decreases in viable cell counts. After the immediate increases, the ODs for A10 and A14 changed little in the first 2 hr. In contrast, the ODs for A11 and A16 decreased rapidly. When peptide A10 was added to suspensions of heat-killed whole cells, crude cell walls and a crude peptidoglycan preparation, their ODs were increased approximately 2-fold. In contrast, the OD was not increased when the peptide was added to a suspension of pure peptidoglycan from which anionic polymers had been removed. Light microscopic and transmission electron microscopic study showed that A10 and A14 inhibited autolysis and that A11 and A16 induced autolysis earlier than the control. These results suggest strongly that the peptides adsorb to and precipitate on the anionic cell surface polymers such as teichoic acid and lipoteichoic acid via ionic interaction. The effects of peptides on the autolysis may be the results of the modification of S. aureus autolysin activities. These peptides, especially the 10-mer peptide B9 (PGTKLYTVPW) that represents the C-terminal half of A10 and N-terminal half of A11, may be important segments for Atl to bind to the cell surface.
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Affiliation(s)
- M Takano
- Pharmaceutical Development Research Laboratory, Tanabe Seiyaku Co., Ltd., Saitama, Japan
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43
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Caldelari I, Loeliger B, Langen H, Glauser MP, Moreillon P. Deregulation of the arginine deiminase (arc) operon in penicillin-tolerant mutants of Streptococcus gordonii. Antimicrob Agents Chemother 2000; 44:2802-10. [PMID: 10991863 PMCID: PMC90154 DOI: 10.1128/aac.44.10.2802-2810.2000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Penicillin tolerance is an incompletely understood phenomenon that allows bacteria to resist drug-induced killing. Tolerance was studied with independent Streptococcus gordonii mutants generated by cyclic exposure to 500 times the MIC of penicillin. Parent cultures lost 4 to 5 log(10) CFU/ml of viable counts/24 h. In contrast, each of four independent mutant cultures lost < or =2 log(10) CFU/ml/24 h. The mutants had unchanged penicillin-binding proteins but contained increased amounts of two proteins with respective masses of ca. 50 and 45 kDa. One mutant (Tol1) was further characterized. The two proteins showing increased levels were homologous to the arginine deiminase and ornithine carbamoyl transferase of other gram-positive bacteria and were encoded by an operon that was >80% similar to the arginine-deiminase (arc) operon of these organisms. Partial nucleotide sequencing and insertion inactivation of the S. gordonii arc locus indicated that tolerance was not a direct consequence of arc alteration. On the other hand, genetic transformation of tolerance by Tol1 DNA always conferred arc deregulation. In nontolerant recipients, arc was repressed during exponential growth and up-regulated during postexponential growth. In tolerant transformants, arc was constitutively expressed. Tol1 DNA transformed tolerance at the same rate as transformation of a point mutation (10(-2) to 10(-3)). The tolerance mutation mapped on a specific chromosomal fragment but was physically distant from arc. Importantly, arc deregulation was observed in most (6 of 10) of additional independent penicillin-tolerant mutants. Thus, although not exclusive, the association between arc deregulation and tolerance was not fortuitous. Since penicillin selection mimicked the antibiotic pressure operating in the clinical environment, arc deregulation might be an important correlate of naturally occurring tolerance and help in understanding the mechanism(s) underlying this clinically problematic phenotype.
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Affiliation(s)
- I Caldelari
- Division of Infectious Diseases, Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland
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Abstract
The Staphylococcus aureus lrgAB operon was recently shown to inhibit extracellular murein hydrolase activity and increase tolerance to penicillin. Further characterization of this operon could provide novel insight into the dynamics of S. aureus cell wall metabolism and the mechanism of penicillin-induced lethality.
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Affiliation(s)
- K W Bayles
- Dept of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052, USA
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45
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Foreman-Wykert AK, Weinrauch Y, Elsbach P, Weiss J. Cell-wall determinants of the bactericidal action of group IIA phospholipase A2 against Gram-positive bacteria. J Clin Invest 1999; 103:715-21. [PMID: 10074489 PMCID: PMC408128 DOI: 10.1172/jci5468] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We have shown previously that a group IIA phospholipase A2 (PLA2) is responsible for the potent bactericidal activity of inflammatory fluids against many Gram-positive bacteria. To exert its antibacterial activity, this PLA2 must first bind and traverse the bacterial cell wall to produce the extensive degradation of membrane phospholipids (PL) required for bacterial killing. In this study, we have examined the properties of the cell-wall that may determine the potency of group IIA PLA2 action. Inhibition of bacterial growth by nutrient deprivation or a bacteriostatic antibiotic reversibly increased bacterial resistance to PLA2-triggered PL degradation and killing. Conversely, pretreatment of Staphylococcus aureus or Enterococcus faecium with subinhibitory doses of beta-lactam antibiotics increased the rate and extent of PL degradation and/or bacterial killing after addition of PLA2. Isogenic wild-type (lyt+) and autolysis-deficient (lyt-) strains of S. aureus were equally sensitive to the phospholipolytic action of PLA2, but killing and lysis was much greater in the lyt+ strain. Thus, changes in cell-wall cross-linking and/or autolytic activity can modulate PLA2 action either by affecting enzyme access to membrane PL or by the coupling of massive PL degradation to autolysin-dependent killing and bacterial lysis or both. Taken together, these findings suggest that the bacterial envelope sites engaged in cell growth may represent preferential sites for the action and cytotoxic consequences of group IIA PLA2 attack against Gram-positive bacteria.
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Affiliation(s)
- A K Foreman-Wykert
- Department of Microbiology, New York University School of Medicine, New York 10016, USA
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46
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Navarre WW, Schneewind O. Surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. Microbiol Mol Biol Rev 1999; 63:174-229. [PMID: 10066836 PMCID: PMC98962 DOI: 10.1128/mmbr.63.1.174-229.1999] [Citation(s) in RCA: 925] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins.
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Affiliation(s)
- W W Navarre
- Department of Microbiology & Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA
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47
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Giesbrecht P, Kersten T, Maidhof H, Wecke J. Staphylococcal cell wall: morphogenesis and fatal variations in the presence of penicillin. Microbiol Mol Biol Rev 1998; 62:1371-414. [PMID: 9841676 PMCID: PMC98950 DOI: 10.1128/mmbr.62.4.1371-1414.1998] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The primary goal of this review is to provide a compilation of the complex architectural features of staphylococcal cell walls and of some of their unusual morphogenetic traits including the utilization of murosomes and two different mechanisms of cell separation. Knowledge of these electron microscopic findings may serve as a prerequisite for a better understanding of the sophisticated events which lead to penicillin-induced death. For more than 50 years there have been controversial disputes about the mechanisms by which penicillin kills bacteria. Many hypotheses have tried to explain this fatal event biochemically and mainly via bacteriolysis. However, indications that penicillin-induced death of staphylococci results from overall biochemical defects or from a fatal attack of bacterial cell walls by bacteriolytic murein hydrolases were not been found. Rather, penicillin, claimed to trigger the activity of murein hydrolases, impaired autolytic wall enzymes of staphylococci. Electron microscopic investigations have meanwhile shown that penicillin-mediated induction of seemingly minute cross wall mistakes is the very reason for this killing. Such "morphogenetic death" taking place at predictable cross wall sites and at a predictable time is based on the initiation of normal cell separations in those staphylococci in which the completion of cross walls had been prevented by local penicillin-mediated impairment of the distribution of newly synthesized peptidoglycan; this death occurs because the high internal pressure of the protoplast abruptly kills such cells via ejection of some cytoplasm during attempted cell separation. An analogous fatal onset of cell partition is considered to take place without involvement of a detectable quantity of autolytic wall enzymes ("mechanical cell separation"). The most prominent feature of penicillin, the disintegration of bacterial cells via bacteriolysis, is shown to represent only a postmortem process resulting from shrinkage of dead cells and perturbation of the cytoplasmic membrane. Several schematic drawings have been included in this review to facilitate an understanding of the complex morphogenetic events.
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Młynarczyk A, Młynarczyk G, Jeljaszewicz J. The genome of Staphylococcus aureus: a review. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1998; 287:277-314. [PMID: 9638861 DOI: 10.1016/s0934-8840(98)80165-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The genome of Staphylococcus aureus consists of a single circular chromosome (2.7-2.8 mbp) plus an assortment of extrachromosomal accessory genetic elements: conjugative and nonconjugative plasmids, mobile elements (IS, Tn, Hi), prophages and other variable elements. Plasmids (1-60 kbp) are classified into 4 classes and there are 15 known incompatibility groups. Mobile elements of the genome (0.8-18 kbp) appear in the chromosome or in plasmids of classes II and III. Prophages (45-60 kbp) are integrated in the bacterial chromosome, and they are UV- or mitomycin-inducible. Temperate bacteriophages of S. aureus are members of the Siphoviridae and the serological groups A, B and F occur most frequently. In the paper presented, the characteristics of chromosome, plasmids, transposons and other genetic elements of S. aureus genome are given and an alphabetical list of known genes of this species is included.
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