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Pettersen JS, Nielsen FD, Andreassen PR, Møller-Jensen J, Jørgensen M. A comprehensive analysis of pneumococcal two-component system regulatory networks. NAR Genom Bioinform 2024; 6:lqae039. [PMID: 38650915 PMCID: PMC11034029 DOI: 10.1093/nargab/lqae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Two-component systems are key signal-transduction systems that enable bacteria to respond to a wide variety of environmental stimuli. The human pathogen, Streptococcus pneumoniae (pneumococcus) encodes 13 two-component systems and a single orphan response regulator, most of which are significant for pneumococcal pathogenicity. Mapping the regulatory networks governed by these systems is key to understand pneumococcal host adaptation. Here we employ a novel bioinformatic approach to predict the regulons of each two-component system based on publicly available whole-genome sequencing data. By employing pangenome-wide association studies (panGWAS) to predict genotype-genotype associations for each two-component system, we predicted regulon genes of 11 of the pneumococcal two-component systems. Through validation via next-generation RNA-sequencing on response regulator overexpression mutants, several top candidate genes predicted by the panGWAS analysis were confirmed as regulon genes. The present study presents novel details on multiple pneumococcal two-component systems, including an expansion of regulons, identification of candidate response regulator binding motifs, and identification of candidate response regulator-regulated small non-coding RNAs. We also demonstrate a use for panGWAS as a complementary tool in target gene identification via identification of genotype-to-genotype links. Expanding our knowledge on two-component systems in pathogens is crucial to understanding how these bacteria sense and respond to their host environment, which could prove useful in future drug development.
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Affiliation(s)
- Jens Sivkær Pettersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Flemming Damgaard Nielsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
| | | | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Mikkel Girke Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Du J, Huang S, Wu M, Chen S, Zhou W, Zhan L, Huang X. Dlt operon regulates physiological function and cariogenic virulence in Streptococcus mutans. Future Microbiol 2023; 18:225-233. [PMID: 37097048 DOI: 10.2217/fmb-2022-0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Streptococcus mutans is one of the major cariogenic pathogens in the oral cavity. The dlt operon is responsible for the process of D-alanylation of lipoteichoic acid and is related to the virulence of S. mutans. The dlt operon contributes to the adhesion, biofilm formation, stress response, interspecies competitiveness and autolysis of S. mutans. In addition, we have summarized the possible regulatory networks of the dlt operon. This review highlights the significant role of the dlt operon in S. mutans and provides new ideas for ecological caries prevention.
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Affiliation(s)
- Jingyun Du
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Shan Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Minjing Wu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
- Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Shuai Chen
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Wen Zhou
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Ling Zhan
- Division of Pediatric Dentistry, Department of Orofacial Sciences, Department of Preventive & Restorative Dental Sciences, University of California, San Francisco, CA, USA
| | - Xiaojing Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College & University, School & Hospital of Stomatology, Fujian Medical University, Fuzhou, China
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Wu M, Huang S, Du J, Li Y, Jiang S, Zhan L, Huang X. D-alanylation of lipoteichoic acid contributes to biofilm formation and acidogenesis capacity of Streptococcusmutans. Microb Pathog 2022; 169:105666. [PMID: 35811023 DOI: 10.1016/j.micpath.2022.105666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/15/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND D-alanylation of Lipoteichoic acid (LTA) is considered to be essential for virulence factors expression in Gram-positive microorganism. The effects of the D-alanylation of LTA on biofilm formation and acidogenesis of Streptococcus mutans (S. mutans) are still not clearly understood. AIM This study was designed to investigate the impact of D-alanylation of LTA on biofilm formation and acidogenesis of S. mutans and explore the related mechanisms. METHODS AND MATERIAL We compared the biofilm formation process by fluorescence microscope observation of LTA D-alanylation blocking strain with that of the wildtype strain. Auto-aggregation, cell surface charge, and polysaccharide production assays were performed to investigate the related mechanisms. pH drop assay and glycolysis pH drop-down analysis were carried out to evaluate the acidogenesis capacity of S. mutans after LTA D-alanylation blocking. To identify the biofilm formation and adhesive-related genes expressions of S. mutans mutant, qRT-PCR was performed. RESULTS After blocking off the D-alanylation of LTA, S. mutans could not form the three-dimensional structural biofilm, in which cells were scattered on the substratum as small clusters. The auto-aggregation was prompted due to the mutant strain cell morphology change (*p < 0.05). Furthermore, more negative charges were found on the mutant strain cells surfaces and fewer water-insoluble glucans were produced in mutant biofilm (*p < 0.05). The adhesion capacity of the S. mutans biofilm was impaired after LTA D-alanylation blocking (*p < 0.05). Biofilm formation and adhesive-related genes expressions decreased (*p < 0.05), especially at the early stages of biofilm formation. S. mutans mutant strains exhibited suppressed acidogenesis because its glycolytic activity was impaired. CONCLUSION The results of this study suggest that blocking of LTA D-alanylation disrupts normal biofilm formation in S. mutans predominantly if not entirely by altering intercellular auto-aggregation, cell adhesion, and extracellular matrix formation. Moreover, our study results suggest that the LTA D-alanylation plays an important role in S. mutans acidogenesis by altering glycolytic activity. These findings add to the knowledge about mechanisms underlying biofilm formation and acid tolerance in S. mutans.
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Affiliation(s)
- Minjing Wu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China; Stomatological Hospital, Southern Medical University, Guangzhou, China.
| | - Shan Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China.
| | - Jingyun Du
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Yijun Li
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Shan Jiang
- Southern Medical University, Shenzhen Stomatology Hospital (Pingshan), China
| | - Ling Zhan
- Division of Pediatric Dentistry, Department of Orofacial Sciences, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, USA.
| | - Xiaojing Huang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China.
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Enoxacin-based derivatives: antimicrobial and antibiofilm agent: a biology-oriented drug synthesis (BIODS) approach. Future Med Chem 2022; 14:947-962. [PMID: 35695000 DOI: 10.4155/fmc-2022-0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: To find alternative molecules against Klebsiella pneumonia, Proteus mirabilis and methicillin-resistant Staphylococcus aureus, new enoxacin derivatives were synthesized and screened. Methods: All derivatives exhibited promising antibacterial activities as compared to standard enoxacin (2 μg/ml) and standard cefixime (82 μg/ml). Compounds 2, 3 and 5 significantly downregulated the gene expression of biofilm-forming genes. Conclusion: Based on our results, these molecules may serve as potential drug candidates to cure several bacterial infections in the future.
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Yang X, Peng W, Wang N, Dou B, Yang F, Chen H, Yuan F, Bei W. Role of the Two-Component System CiaRH in the Regulation of Efflux Pump SatAB and Its Correlation with Fluoroquinolone Susceptibility. Microbiol Spectr 2022; 10:e0041722. [PMID: 35638854 PMCID: PMC9241815 DOI: 10.1128/spectrum.00417-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/04/2022] [Indexed: 11/26/2022] Open
Abstract
Streptococcus suis is an important pathogen in both pigs and humans. Although the diseases associated with S. suis can typically be treated with antibiotics, such use has resulted in a sustained increase in drug resistance. Bacteria can sense and respond to antibiotics via two-component systems (TCSs). In this study, the TCS CiaRH was identified as playing an important role in the susceptibility of S. suis to fluoroquinolones (FQs). We found that a ΔciaRH mutant possessed lower susceptibility to FQs than the wild-type strain, with no observed growth defects at the tested concentrations and lower levels of intracellular drugs and dye. Proteomic data revealed that the levels of SatA and SatB expression were upregulated in the ΔciaRH mutant compared with their levels in the wild-type strain. The satA and satB genes encode a narrow-spectrum FQ efflux pump. The phenomena associated with combined ciaRH-and-satAB deletion mutations almost returned the ΔciaRH ΔsatAB mutant to the phenotype of the wild-type strain compared to the phenotype of the ΔciaRH mutant, suggesting that the resistance of the ΔciaRH strain to FQs could be attributed to satAB overexpression. Moreover, SatAB expression was regulated by CiaR (a response regulator of CiaRH) and SatR (a regulator of the MarR family). The ciaRH genes were consistently downregulated in response to antibiotic stress. The results of electrophoretic mobility shift assays (EMSAs) and affinity assays revealed that both regulator proteins directly controlled the ABC transporter proteins SatAB. Together, the results show that cascade-mediated regulation of antibiotic export by CiaRH is crucial for the ability of S. suis to adapt to conditions of antibiotic pressure. Our study may provide a new target for future antibiotic research and development. IMPORTANCE Streptococcus suis is a zoonotic pathogen with high incidence and mortality rates in both swine and humans. Following antibiotic treatment, the organism has evolved many resistance mechanisms, among which efflux pump overexpression can promote drug extrusion from the cell. This study clarified the role of CiaRH in fluoroquinolone resistance. A mutant with the ciaRH genes deleted showed decreased susceptibility to the antibiotics tested, an invariant growth rate, and reduced intracellular efflux pump substrates. This research also demonstrated that overexpression of the efflux pump SatAB was the main cause of ΔciaRH resistance. In addition, CiaR could combine with the promoter region of satAB to further directly suppress target gene transcription. Simultaneously, satAB was also directly regulated by SatR. Our findings may provide novel insights for the development of drug targets and help to exploit corresponding inhibitors to combat bacterial multidrug resistance.
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Affiliation(s)
- Xia Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Wei Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Ningning Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Beibei Dou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fengming Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fangyan Yuan
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
- Guangxi Yangxiang Co., Ltd., Guigang, China
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Jiang N, Zhao S, Wang S, Lu Z. Proteomics of Streptococcus mutans to Reveal the Antibiofilm Formation Mechanism of Ag/ZnO Nanocomposites with Light-Emitting Diode Radiation. Int J Nanomedicine 2021; 16:7741-7757. [PMID: 34848957 PMCID: PMC8612293 DOI: 10.2147/ijn.s333432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/30/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction As a biofilm-associated disease, dental caries benefits from nanoparticle (NP)-based therapies. Streptococcus mutans (S. mutans) is a primary aetiologic agent for dental caries development. We successfully applied a synergistic therapy of Ag/ZnO nanocomposites combined with light-emitting diode (LED) radiation to inhibit S. mutans biofilms. However, the antibiofilm mechanism has not been fully elucidated, and little is known about the biofilm formation ability of bacteria that survive NP-based therapies. Methods This study explored the antibiofilm formation mechanism of this synergistic therapy by an integrated approach based upon proteomics. Results Synergistic therapy killed 99.8% of bacteria, while the biofilm formation ability of 0.2% surviving bacteria was inhibited. The proteomic responses of S. mutans to synergistic therapy were comprehensively characterized to unveil the mechanism of bacterial death and biofilm formation inhibition of the surviving bacteria. In total, 55 differentially expressed proteins (12 upregulated and 43 downregulated) were recorded. The bioinformatic analysis demonstrated that cellular integrity damage and regulated expression of structure-associated proteins were the main reasons for bacterial death. In addition, the proteomic study indicated the potential inhibition of metabolism in surviving bacteria and provided a biofilm-related network consisting of 17 differentially expressed proteins, explaining the multiantibiofilm formation actions. Finally, we reported and verified the inhibitory effects of synergistic therapy on sucrose metabolism and D-alanine metabolism, which disturbed the biofilm formation of surviving bacteria. Conclusion Our findings demonstrated that synergistic therapy killed most bacteria and inhibited the surviving bacteria from forming biofilms. Furthermore, the antibiofilm formation mechanism was revealed by proteomics analysis of S. mutans after synergistic therapy and subsequent metabolic studies. Our success may provide a showcase to explore the antibiofilm formation mechanism of NP-based therapies using proteomic studies.
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Affiliation(s)
- Nan Jiang
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, 430205, People's Republic of China
| | - Shuaiwei Zhao
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, 430205, People's Republic of China
| | - Shilei Wang
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, 430205, People's Republic of China
| | - Zhong Lu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, 430205, People's Republic of China
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He LY, Le YJ, Guo Z, Li S, Yang XY. The Role and Regulatory Network of the CiaRH Two-Component System in Streptococcal Species. Front Microbiol 2021; 12:693858. [PMID: 34335522 PMCID: PMC8317062 DOI: 10.3389/fmicb.2021.693858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/15/2021] [Indexed: 11/13/2022] Open
Abstract
Pathogenic streptococcal species are responsible for a broad spectrum of human diseases ranging from non-invasive and localized infections to more aggressive and life-threatening diseases, which cause great economic losses worldwide. Streptococci possess a dozen two-component systems (TCSs) that play important roles in the response to different environmental changes and adjust the expression of multiple genes to successfully colonize and infect host cells. In this review, we discuss the progress in the study of a conserved TCS named CiaRH in pathogenic or opportunistic streptococci including Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus mutans, Streptococcus gordonii, Streptococcus sanguinis, and Streptococcus suis, focusing on the function and regulatory networks of CiaRH, which will provide a promising strategy for the exploration of novel antistreptococcal therapies. This review highlights the important role of CiaRH and provides an important basis for the development of antistreptococcal drugs and vaccines.
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Affiliation(s)
- Li-Yuan He
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Yao-Jin Le
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Zhong Guo
- Center for Biological Science and Technology, Beijing Normal University, Zhuhai, China
| | - Sha Li
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Xiao-Yan Yang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
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Wu M, Huang S, Du J, Jiang S, Cai Z, Zhan L, Huang X. Role of D-alanylation of Streptococcus mutans lipoteichoic acid in interspecies competitiveness. Mol Oral Microbiol 2021; 36:233-242. [PMID: 33977670 DOI: 10.1111/omi.12344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The D-alanylation of lipoteichoic acid (LTA) is essential for the physiological metabolism of Streptococcus mutans (S. mutans). This study was designed to investigate the influence of D-alanylation of LTA on interspecies competitiveness of S. mutans. METHODS The process of D-alanylation was blocked by the inactivation of dltC. Agar competition assays, conditioned medium assays, and qRT-PCR were used to evaluate the production of antimicrobial compounds in S. mutans mutant. Dual-species biofilm was formed to investigate the competitiveness of S. mutans mutant cocultured with S. sanguinis or S. gordonii. RESULTS S. mutans mutant could not produce antimicrobial compounds efficiently when cocultured with commensal bacteria (*p < 0.05). The mutant showed compromised competitiveness in dual-species biofilms. The ratio of the mutant in dual-species biofilms decreased, and the terminal pH of the culture medium in mutant groups (mutant+S. sanguinis/S. gordonii) was higher than that in wild-type groups (*p < 0.05). Scanning electron microscope (SEM) showed weaker demineralization of enamel treated with dual-species biofilms consisting of mutant and commensal bacteria. CONCLUSION D-Alanylation is involved in interspecies competitiveness of S. mutans within oral biofilm by regulating mutacins and lactic acid production, which may modulate the profiles of dental biofilms. Results provide new insights into dental caries prevention and treatment.
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Affiliation(s)
- Minjing Wu
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China.,Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Shan Huang
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Jingyun Du
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Shan Jiang
- School of Stomatology, Shenzhen University Health Science Center, Shenzhen, China
| | - Zhiyu Cai
- Department of Stomatology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Ling Zhan
- Division of Pediatric Dentistry, Department of Orofacial Sciences, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, CA, USA
| | - Xiaojing Huang
- Fujian Key Laboratory of Oral Diseases &, Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
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Ridyard KE, Overhage J. The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent. Antibiotics (Basel) 2021; 10:antibiotics10060650. [PMID: 34072318 PMCID: PMC8227053 DOI: 10.3390/antibiotics10060650] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.
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Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation. Molecules 2020; 25:molecules25092232. [PMID: 32397430 PMCID: PMC7249192 DOI: 10.3390/molecules25092232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/02/2020] [Accepted: 05/05/2020] [Indexed: 11/19/2022] Open
Abstract
Dental caries is a diet–biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.
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Identification of Pneumococcal Factors Affecting Pneumococcal Shedding Shows that the dlt Locus Promotes Inflammation and Transmission. mBio 2019; 10:mBio.01032-19. [PMID: 31213554 PMCID: PMC6581856 DOI: 10.1128/mbio.01032-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a common cause of respiratory tract and invasive infection. The overall effectiveness of immunization with the organism’s capsular polysaccharide depends on its ability to block colonization of the upper respiratory tract and thereby prevent host-to-host transmission. Because of the limited coverage of current pneumococcal vaccines, we carried out an unbiased in vivo transposon mutagenesis screen to identify pneumococcal factors other than its capsular polysaccharide that affect transmission. One such candidate was expressed by the dlt locus, previously shown to add d-alanine onto the pneumococcal lipoteichoic acid present on the bacterial cell surface. This modification protects against host antimicrobials and augments host inflammatory responses. The latter increases secretions and bacterial shedding from the upper respiratory tract to allow for transmission. Thus, this study provides insight into a mechanism employed by the pneumococcus to successfully transit from one host to another. Host-to-host transmission is a necessary but poorly understood aspect of microbial pathogenesis. Herein, we screened a genomic library of mutants of the leading respiratory pathogen Streptococcus pneumoniae generated by mariner transposon mutagenesis (Tn-Seq) to identify genes contributing to its exit or shedding from the upper respiratory tract (URT), the limiting step in the organism’s transmission in an infant mouse model. Our analysis focused on genes affecting the bacterial surface that directly impact interactions with the host. Among the multiple factors identified was the dlt locus, which adds d-alanine onto lipoteichoic acids (LTA) and thereby increases Toll-like receptor 2-mediated inflammation and resistance to antimicrobial peptides. The more robust proinflammatory response in the presence of d-alanylation promotes secretions that facilitate pneumococcal shedding and allows for transmission. Expression of the dlt locus is controlled by the CiaRH system, which senses cell wall stress in response to antimicrobial activity, including in response to lysozyme, the most abundant antimicrobial along the URT mucosa. Accordingly, in a lysM−/− host, there was no longer an effect of the dlt locus on pneumococcal shedding. Thus, our findings demonstrate how a pathogen senses the URT milieu and then modifies its surface characteristics to take advantage of the host response for transit to another host.
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Castillo Pedraza MC, Rosalen PL, de Castilho ARF, Freires IDA, de Sales Leite L, Faustoferri RC, Quivey RG, Klein MI. Inactivation of Streptococcus mutans genes lytST and dltAD impairs its pathogenicity in vivo. J Oral Microbiol 2019; 11:1607505. [PMID: 31143407 PMCID: PMC6522913 DOI: 10.1080/20002297.2019.1607505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/19/2022] Open
Abstract
Background: Streptococcus mutans orchestrates the development of a biofilm that causes dental caries in the presence of dietary sucrose, and, in the bloodstream, S. mutans can cause systemic infections. The development of a cariogenic biofilm is dependent on the formation of an extracellular matrix rich in exopolysaccharides, which contains extracellular DNA (eDNA) and lipoteichoic acids (LTAs). While the exopolysaccharides are virulence markers, the involvement of genes linked to eDNA and LTAs metabolism in the pathogenicity of S. mutans remains unclear. Objective and Design: In this study, a parental strain S. mutans UA159 and derivative strains carrying single gene deletions were used to investigate the role of eDNA (ΔlytS and ΔlytT), LTA (ΔdltA and ΔdltD), and insoluble exopolysaccharides (ΔgtfB) in virulence in a rodent model of dental caries (rats) and a systemic infection model (Galleria mellonella larvae). Results: Fewer carious lesions were observed on smooth and sulcal surfaces of enamel and dentin of the rats infected with ∆lytS, ∆dltD, and ΔgtfB (vs. the parental strain). Moreover, strains carrying gene deletions prevented the killing of larvae (vs. the parental strain). Conclusions: Altogether, these findings indicate that inactivation of lytST and dltAD impaired S. mutans cariogenicity and virulence in vivo.
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Affiliation(s)
- Midian C Castillo Pedraza
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | - Pedro L Rosalen
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Aline Rogéria Freire de Castilho
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil.,Department of Pediatric Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Irlan de Almeida Freires
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Luana de Sales Leite
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | | | - Robert G Quivey
- Center for Oral Biology, University of Rochester, Rochester, NY, USA
| | - Marlise I Klein
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
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13
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Arii K, Kawada‐Matsuo M, Oogai Y, Noguchi K, Komatsuzawa H. Single mutations in BraRS confer high resistance against nisin A in Staphylococcus aureus. Microbiologyopen 2019; 8:e791. [PMID: 30656859 PMCID: PMC6854852 DOI: 10.1002/mbo3.791] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 01/09/2023] Open
Abstract
Nisin A is a lantibiotic produced by Lactococcus lactis that is widely used as a food preservative. In Staphylococcus aureus, the BraRS two‐component system (TCS) senses nisin A and regulates the expression of the ABC transporter VraDE, which is responsible for nisin A resistance. In this study, we exposed S. aureus to a sub‐minimum inhibition concentration of nisin A and obtained three spontaneous mutants that were highly resistant to this lantibiotic, designated as SAN (S. aureus nisin resistant) 1, SAN8, and SAN87. In the wild‐type S. aureus strain, VraDE expression was induced by nisin A. In contrast, SAN8 and SAN87 showed constitutively high VraDE expression, even in the absence of nisin A, while SAN1 showed higher BraRS expression, which resulted in high VraDE expression in the presence of nisin A. We identified a single mutation in the promoter region of braXRS in SAN1, whereas SAN8 and SAN87 had single mutations in braR and braS, respectively. Interestingly, even the unphosphorylated form of the mutant BraR protein induced VraDE expression. These results indicate that conformational changes in BraS or BraR resulting from the point mutations may result in the constitutive expression of VraDE, allowing S. aureus to adapt to high concentrations of nisin A.
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Affiliation(s)
- Kaoru Arii
- Department of Oral MicrobiologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
- Department of PeriodontologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Miki Kawada‐Matsuo
- Department of Oral MicrobiologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Yuichi Oogai
- Department of Oral MicrobiologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Kazuyuki Noguchi
- Department of PeriodontologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Hitoshi Komatsuzawa
- Department of Oral MicrobiologyKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
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14
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Wood BM, Santa Maria JP, Matano LM, Vickery CR, Walker S. A partial reconstitution implicates DltD in catalyzing lipoteichoic acid d-alanylation. J Biol Chem 2018; 293:17985-17996. [PMID: 30237166 PMCID: PMC6240853 DOI: 10.1074/jbc.ra118.004561] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/27/2018] [Indexed: 12/19/2022] Open
Abstract
Modifications to the Gram-positive bacterial cell wall play important roles in antibiotic resistance and pathogenesis, but the pathway for the d-alanylation of teichoic acids (DLT pathway), a ubiquitous modification, is poorly understood. The d-alanylation machinery includes two membrane proteins of unclear function, DltB and DltD, which are somehow involved in transfer of d-alanine from a carrier protein inside the cell to teichoic acids on the cell surface. Here, we probed the role of DltD in the human pathogen Staphylococcus aureus using both cell-based and biochemical assays. We first exploited a known synthetic lethal interaction to establish the essentiality of each gene in the DLT pathway for d-alanylation of lipoteichoic acid (LTA) and confirmed this by directly detecting radiolabeled d-Ala-LTA both in cells and in vesicles prepared from mutant strains of S. aureus We developed a partial reconstitution of the pathway by using cell-derived vesicles containing DltB, but no other components of the d-alanylation pathway, and showed that d-alanylation of previously formed lipoteichoic acid in the DltB vesicles requires the presence of purified and reconstituted DltA, DltC, and DltD, but not of the LTA synthase LtaS. Finally, based on the activity of DltD mutants in cells and in our reconstituted system, we determined that Ser-70 and His-361 are essential for d-alanylation activity, and we propose that DltD uses a catalytic dyad to transfer d-alanine to LTA. In summary, we have developed a suite of assays for investigating the bacterial DLT pathway and uncovered a role for DltD in LTA d-alanylation.
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Affiliation(s)
- B McKay Wood
- From the Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - John P Santa Maria
- From the Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Leigh M Matano
- From the Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Christopher R Vickery
- From the Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Suzanne Walker
- From the Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115.
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15
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Molecular mechanisms of polymyxin resistance and detection of mcr genes. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2018; 163:28-38. [PMID: 30439931 DOI: 10.5507/bp.2018.070] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/26/2018] [Indexed: 12/12/2022] Open
Abstract
Antibiotic resistance is an ever-increasing global problem. Major commercial antibiotics often fail to fight common bacteria, and some pathogens have become multi-resistant. Polymyxins are potent bactericidal antibiotics against gram-negative bacteria. Known resistance to polymyxin includes intrinsic, mutational and adaptive mechanisms, with the recently described horizontally acquired resistance mechanisms. In this review, we present several strategies for bacteria to develop enhanced resistance to polymyxins, focusing on changes in the outer membrane, efflux and other resistance determinants. Better understanding of the genes involved in polymyxin resistance may pave the way for the development of new and effective antimicrobial agents. We also report novel in silico tested primers for PCR assay that may be able distinguish colistin-resistant isolates carrying the plasmid-encoded mcr genes and will assist in combating the spread of colistin resistance in bacteria.
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16
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Hirt H, Hall JW, Larson E, Gorr SU. A D-enantiomer of the antimicrobial peptide GL13K evades antimicrobial resistance in the Gram positive bacteria Enterococcus faecalis and Streptococcus gordonii. PLoS One 2018; 13:e0194900. [PMID: 29566082 PMCID: PMC5864073 DOI: 10.1371/journal.pone.0194900] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/12/2018] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial peptides represent an alternative to traditional antibiotics that may be less susceptible to bacterial resistance mechanisms by directly attacking the bacterial cell membrane. However, bacteria have a variety of defense mechanisms that can prevent cationic antimicrobial peptides from reaching the cell membrane. The L- and D-enantiomers of the antimicrobial peptide GL13K were tested against the Gram-positive bacteria Enterococcus faecalis and Streptococcus gordonii to understand the role of bacterial proteases and cell wall modifications in bacterial resistance. GL13K was derived from the human salivary protein BPIFA2. Minimal inhibitory concentrations were determined by broth dilution and a serial assay used to determine bacterial resistance. Peptide degradation was determined in a bioassay utilizing a luminescent strain of Pseudomonas aeruginosa to detect peptide activity. Autolysis and D-alanylation-deficient strains of E. faecalis and S. gordonii were tested in autolysis assays and peptide activity assays. E. faecalis protease inactivated L-GL13K but not D-GL13K, whereas autolysis did not affect peptide activity. Indeed, the D-enantiomer appeared to kill the bacteria prior to initiation of autolysis. D-alanylation mutants were killed by L-GL13K whereas this modification did not affect killing by D-GL13K. The mutants regained resistance to L-GL13K whereas bacteria did not gain resistance to D-GL13K after repeated treatment with the peptides. D-alanylation affected the hydrophobicity of bacterial cells but hydrophobicity alone did not affect GL13K activity. D-GL13K evades two resistance mechanisms in Gram-positive bacteria without giving rise to substantial new resistance. D-GL13K exhibits attractive properties for further antibiotic development.
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Affiliation(s)
- Helmut Hirt
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Jeffrey W. Hall
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Elliot Larson
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Sven-Ulrik Gorr
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
- * E-mail:
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17
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Hall CW, Mah TF. Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria. FEMS Microbiol Rev 2018; 41:276-301. [PMID: 28369412 DOI: 10.1093/femsre/fux010] [Citation(s) in RCA: 819] [Impact Index Per Article: 136.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/22/2017] [Indexed: 02/06/2023] Open
Abstract
Biofilms are surface-attached groups of microbial cells encased in an extracellular matrix that are significantly less susceptible to antimicrobial agents than non-adherent, planktonic cells. Biofilm-based infections are, as a result, extremely difficult to cure. A wide range of molecular mechanisms contribute to the high degree of recalcitrance that is characteristic of biofilm communities. These mechanisms include, among others, interaction of antimicrobials with biofilm matrix components, reduced growth rates and the various actions of specific genetic determinants of antibiotic resistance and tolerance. Alone, each of these mechanisms only partially accounts for the increased antimicrobial recalcitrance observed in biofilms. Acting in concert, however, these defences help to ensure the survival of biofilm cells in the face of even the most aggressive antimicrobial treatment regimens. This review summarises both historical and recent scientific data in support of the known biofilm resistance and tolerance mechanisms. Additionally, suggestions for future work in the field are provided.
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18
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Khan AK, Ahmed A, Hussain M, Khan IA, Ali SA, Farooq AD, Faizi S. Antibiofilm potential of 16-oxo-cleroda-3, 13(14) E-diene-15 oic acid and its five new γ-amino γ-lactone derivatives against methicillin resistant Staphylococcus aureus and Streptococcus mutans. Eur J Med Chem 2017; 138:480-490. [DOI: 10.1016/j.ejmech.2017.06.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 06/23/2017] [Accepted: 06/28/2017] [Indexed: 12/18/2022]
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19
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Antibacterial effect on mature biofilms of oral streptococci and antioxidant activity of 3β,6β,16β-trihydroxylup-20(29)-ene from Combretum leprosum. Med Chem Res 2017. [DOI: 10.1007/s00044-017-2022-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Wang Z, Shen Y, Haapasalo M. Antibiofilm peptides against oral biofilms. J Oral Microbiol 2017; 9:1327308. [PMID: 28748031 PMCID: PMC5508375 DOI: 10.1080/20002297.2017.1327308] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 05/01/2017] [Accepted: 04/12/2017] [Indexed: 12/21/2022] Open
Abstract
The oral cavity is a major entry point for bacteria and other microorganisms. Oral biofilms are formed by mixed communities of microorganisms embedded in an exopolysaccharide matrix. Biofilms forming on dental hard or soft tissue are the major cause of caries and endodontic and periodontal disease. Human oral biofilms exhibit high resistance to antimicrobial agents. Antibiofilm peptides constitute a diverse class of host-defense molecules that act to combat invasion and infection with biofilms. Different in vitro and in vivo biofilm models with quantitative analysis have been established to provide predictable platforms for the evaluation of the antibiofilm effect of oral antibiofilm peptides. These peptides have engendered considerable interest in the past decades as potential alternatives to traditional disinfecting agents due to their ability to target bacterial biofilms specifically, leading to the prevention of biofilm formation and destruction of pre-existing biofilms by Gram-positive and -negative bacterial pathogens and fungi. At the same time, challenges associated with the application of these antibiofilm peptides in dental practice also exist. The production of effective, nontoxic, and stable antibiofilm peptides is desired in both academic and industrial fields. This review focuses on the antibiofilm properties of current synthetic peptides and their application in different areas of dentistry.
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Affiliation(s)
- Zhejun Wang
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Markus Haapasalo
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
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21
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Marsh PD, Do T, Beighton D, Devine DA. Influence of saliva on the oral microbiota. Periodontol 2000 2017; 70:80-92. [PMID: 26662484 DOI: 10.1111/prd.12098] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2015] [Indexed: 11/28/2022]
Abstract
Saliva plays a major role in determining the composition and activity of the oral microbiota, via a variety of mechanisms. Molecules, mainly from saliva, form a conditioning film on oral surfaces, thus providing receptors for bacterial attachment. The attached cells use saliva components, such as glycoproteins, as their main source of nutrients for growth. Oral bacteria work sequentially and in a concerted manner to catabolize these structurally complex molecules. Saliva also buffers the pH in the biofilm to around neutrality, creating an environment which is conducive to the growth of many oral bacteria that provide important benefits to the host. Components of the adaptive and innate host defences are delivered by saliva, and these often function synergistically, and at sublethal concentrations, so a complex relationship develops between the host and the resident microbiota. Dysbiosis can occur rapidly if the flow of saliva is perturbed.
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22
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Kawada-Matsuo M, Komatsuzawa H. Role of Streptococcus mutans two-component systems in antimicrobial peptide resistance in the oral cavity. JAPANESE DENTAL SCIENCE REVIEW 2017; 53:86-94. [PMID: 28725299 PMCID: PMC5501732 DOI: 10.1016/j.jdsr.2016.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 10/14/2016] [Accepted: 12/08/2016] [Indexed: 01/24/2023] Open
Abstract
Approximately 100 trillion microorganisms exist in the oral cavity. For the commensal bacteria of the oral cavity, it is important to adapt to environmental stimuli, including human- or bacteria-derived antimicrobial agents. Recently, bacterial-specific signal transduction regulatory systems, called two-component systems (TCSs), which appear to be focused on sensing and adapting to the environment, were discovered. Streptococcus mutans is an oral commensal bacteria and is also known as a cariogenic bacteria. Although the virulence factors of S. mutans have been well demonstrated, the mechanism underlying the adaptation of the species to the oral cavity is poorly understood. S. mutans UA159 has 15 sets of TCSs. Among them, several have been demonstrated to be involved in acid tolerance, competence and biofilm formation. Recently, together with our findings, it was demonstrated that 5 TCSs were involved in resistance to antimicrobial agents. Furthermore, another TCS was associated with the production of bacteriocin. Six of 15 TCSs are associated with antimicrobial agents, implying that S. mutans can survive in the oral cavity by resisting various antimicrobial peptides. In this review, we highlight the role of antimicrobial peptides in the oral cavity.
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Affiliation(s)
- Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Hitoshi Komatsuzawa
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
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23
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The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms. Int J Antimicrob Agents 2016; 48:298-304. [DOI: 10.1016/j.ijantimicag.2016.06.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/27/2016] [Accepted: 06/05/2016] [Indexed: 11/23/2022]
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24
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LaRock CN, Nizet V. Cationic antimicrobial peptide resistance mechanisms of streptococcal pathogens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3047-54. [PMID: 25701232 DOI: 10.1016/j.bbamem.2015.02.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/04/2015] [Accepted: 02/07/2015] [Indexed: 02/06/2023]
Abstract
Cationic antimicrobial peptides (CAMPs) are critical front line contributors to host defense against invasive bacterial infection. These immune factors have direct killing activity toward microbes, but many pathogens are able to resist their effects. Group A Streptococcus, group B Streptococcus and Streptococcus pneumoniae are among the most common pathogens of humans and display a variety of phenotypic adaptations to resist CAMPs. Common themes of CAMP resistance mechanisms among the pathogenic streptococci are repulsion, sequestration, export, and destruction. Each pathogen has a different array of CAMP-resistant mechanisms, with invasive disease potential reflecting the utilization of several mechanisms that may act in synergy. Here we discuss recent progress in identifying the sources of CAMP resistance in the medically important Streptococcus genus. Further study of these mechanisms can contribute to our understanding of streptococcal pathogenesis, and may provide new therapeutic targets for therapy and disease prevention. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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Affiliation(s)
- Christopher N LaRock
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Medicine and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA; Rady Children's Hospital, San Diego, CA, USA.
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25
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Shoji M, Takeshita T, Maruyama F, Inaba H, Imai K, Kawada-Matsuo M. [Recent advances in the field of oral bacteriology]. Nihon Saikingaku Zasshi 2015; 70:333-338. [PMID: 26028214 DOI: 10.3412/jsb.70.333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The oral cavity is inhabited by more than 600 bacterial species; these species compete for nutrients or coexist in order to survive along with the indigenous population. Extreme conditions are prevalent in the oral cavity, and these conditions are influenced by our immunity and variations in nutrition, temperature, and pH. Pathogens that cause dental caries or periodontal disease can survive in these extreme environments; these pathogens are virulent and can cause several diseases. Therefore, research on oral bacteriology is warranted to analyze the virulence factors of these bacteria as well as to ascertain environmental stress responses, interactions between bacteria and human immunity, comparisons of bacterial genomes, and oral microflora. In this review, we provide new data in the fields of bacteriology, immunology, and genomics and describe recent advances in the field of oral bacteriology.
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Affiliation(s)
- Mikio Shoji
- Department of Microbiology and Oral Infection, Unit of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University
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26
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27
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Caswell CC, Oglesby-Sherrouse AG, Murphy ER. Sibling rivalry: related bacterial small RNAs and their redundant and non-redundant roles. Front Cell Infect Microbiol 2014; 4:151. [PMID: 25389522 PMCID: PMC4211561 DOI: 10.3389/fcimb.2014.00151] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/07/2014] [Indexed: 11/13/2022] Open
Abstract
Small RNA molecules (sRNAs) are now recognized as key regulators controlling bacterial gene expression, as sRNAs provide a quick and efficient means of positively or negatively altering the expression of specific genes. To date, numerous sRNAs have been identified and characterized in a myriad of bacterial species, but more recently, a theme in bacterial sRNAs has emerged: the presence of more than one highly related sRNAs produced by a given bacterium, here termed sibling sRNAs. Sibling sRNAs are those that are highly similar at the nucleotide level, and while it might be expected that sibling sRNAs exert identical regulatory functions on the expression of target genes based on their high degree of relatedness, emerging evidence is demonstrating that this is not always the case. Indeed, there are several examples of bacterial sibling sRNAs with non-redundant regulatory functions, but there are also instances of apparent regulatory redundancy between sibling sRNAs. This review provides a comprehensive overview of the current knowledge of bacterial sibling sRNAs, and also discusses important questions about the significance and evolutionary implications of this emerging class of regulators.
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Affiliation(s)
- Clayton C Caswell
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD Regional College of Veterinary Medicine, Virginia Tech Blacksburg, VA, USA
| | - Amanda G Oglesby-Sherrouse
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, MD, USA ; Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, MD, USA
| | - Erin R Murphy
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine Athens, OH, USA
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28
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McLeod FSA, Simmonds RS. Penicillin facilitates the entry of antisense constructs into Streptococcus mutans. FEMS Microbiol Lett 2013; 349:25-31. [PMID: 24111714 DOI: 10.1111/1574-6968.12286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 09/13/2013] [Indexed: 12/01/2022] Open
Abstract
Antisense oligonucleotides (AS-ODN) target genes in a sequence-specific manner inhibit gene function and have potential use as antimicrobial agents. Cell barriers, such as peptidoglycan, cell surface proteins and lipopolysaccharide membranes, prevent delivery of AS-ODN into the bacterial cell, limiting their use as an effective treatment option. The β-lactam antibiotic penicillin was examined for its ability to deliver phosphorothioate oligodeoxyribonucleotides (PS-ODNs) and γ(32) P-ODN into Streptococcus mutans OMZ175. Treatment of lag-phase S. mutans OMZ175 cells with penicillin and FBA (PS-ODN targeting the fructose-biphosphate aldolase gene), resulted in prolonged suppression of growth (> 24 h) and fba expression (656.9 ± 194.4-fold decrease at 5 h). Suppression of both cell growth and fba expression corresponded with a greater amount of γ(32) P-ODN becoming cell associated, with a maximum γ(32) P-ODN concentration per cell achieved 5 h after penicillin treatment (6.50 ± 1.39 × 10(8) molecules per CFU). This study confirms that for S. mutans OMZ175, the peptidoglycan layer acts as a major barrier preventing AS-ODN penetration and suggests that the use of agents such as penicillin that interfere with peptidoglycan integrity can significantly increase the uptake of PS-ODN by these cells.
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Affiliation(s)
- Felicity S A McLeod
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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29
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da Silva BR, de Freitas VAA, Carneiro VA, Arruda FVS, Lorenzón EN, de Aguiar ASW, Cilli EM, Cavada BS, Teixeira EH. Antimicrobial activity of the synthetic peptide Lys-a1 against oral streptococci. Peptides 2013; 42:78-83. [PMID: 23340019 DOI: 10.1016/j.peptides.2012.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/03/2012] [Accepted: 12/03/2012] [Indexed: 11/30/2022]
Abstract
The peptide LYS-[TRP(6)]-Hy-A1 (Lys-a1) is a synthetic derivative of the peptide Hy-A1, initially isolated from the frog species Hypsiboas albopunctatus. According to previous research, it is a molecule with broad antimicrobial activity. The objective of this study was to evaluate the antimicrobial activity of the synthetic peptide Lys-a1 (KIFGAIWPLALGALKNLIK-NH2) on the planktonic and biofilm growth of oral bacteria. The methods used to evaluate antimicrobial activity include the following: determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in microtiter plates for growth in suspension and quantification of biomass by crystal violet staining and counting of colony forming units for biofilm growth. The microorganisms Streptococcus oralis, Streptococcus sanguinis, Streptococcus parasanguinis, Streptococcus salivarius, Streptococcus mutans and Streptococcus sobrinus were grown in Brain Heart Infusion broth at 37°C under atmospheric pressure with 10% CO2. The peptide was solubilized in 0.1% acetic acid (v/v) at various concentrations (500-1.9 μg mL(-1)). Chlorhexidine gluconate 0.12% was used as the positive control, and BHI culture medium was used as the negative control. The tested peptide demonstrated a remarkable antimicrobial effect, inhibiting the planktonic and biofilm growth of all strains tested, even at low concentrations. Thus, the peptide Lys-a1 is an important source for potential antimicrobial agents, especially for the control and prevention of microbial biofilms, which is one of the most important factors in cariogenic processes.
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Affiliation(s)
- Bruno Rocha da Silva
- BioMol Group/DPML/LIBS, Integrate Biomolecules Laboratory, Federal University of Ceara, Fortaleza, CE, Brazil
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dpr and sod in Streptococcus mutans are involved in coexistence with S. sanguinis, and PerR is associated with resistance to H2O2. Appl Environ Microbiol 2012; 79:1436-43. [PMID: 23263955 DOI: 10.1128/aem.03306-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Large numbers of bacteria coexist in the oral cavity. Streptococcus sanguinis, one of the major bacteria in dental plaque, produces hydrogen peroxide (H(2)O(2)), which interferes with the growth of other bacteria. Streptococcus mutans, a cariogenic bacterium, can coexist with S. sanguinis in dental plaque, but to do so, it needs a means of detoxifying the H(2)O(2) produced by S. sanguinis. In this study, we investigated the association of three oxidative stress factors, Dpr, superoxide dismutase (SOD), and AhpCF, with the resistance of S. sanguinis to H(2)O(2). The knockout of dpr and sod significantly increased susceptibility to H(2)O(2), while the knockout of ahpCF had no apparent effect on susceptibility. In particular, dpr inactivation resulted in hypersensitivity to H(2)O(2). Next, we sought to identify the factor(s) involved in the regulation of these oxidative stress genes and found that PerR negatively regulated dpr expression. The knockout of perR caused increased dpr expression levels, resulting in low-level susceptibility to H(2)O(2) compared with the wild type. Furthermore, we evaluated the roles of perR, dpr, and sod when S. mutans was cocultured with S. sanguinis. Culturing of the dpr or sod mutant with S. sanguinis showed a significant decrease in the S. mutans population ratio compared with the wild type, while the perR mutant increased the ratio. Our results suggest that dpr and sod in S. mutans are involved in coexistence with S. sanguinis, and PerR is associated with resistance to H(2)O(2) in regulating the expression of Dpr.
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