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Li J, Lu T, Chu Y, Zhang Y, Zhang J, Fu W, Sun J, Liu Y, Liao X, Zhou Y. Cinnamaldehyde targets SarA to enhance β-lactam antibiotic activity against methicillin-resistant Staphylococcus aureus. MLIFE 2024; 3:291-306. [PMID: 38948140 PMCID: PMC11211666 DOI: 10.1002/mlf2.12121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/02/2024] [Accepted: 02/19/2024] [Indexed: 07/02/2024]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a current global public health problem due to its increasing resistance to the most recent antibiotic therapies. One critical approach is to develop ways to revitalize existing antibiotics. Here, we show that the phytogenic compound cinnamaldehyde (CIN) and β-lactam antibiotic combinations can functionally synergize and resensitize clinical MRSA isolates to β-lactam therapy and inhibit MRSA biofilm formation. Mechanistic studies indicated that the CIN potentiation effect on β-lactams was primarily the result of inhibition of the mecA expression by targeting the staphylococcal accessory regulator sarA. CIN alone or in combination with β-lactams decreased sarA gene expression and increased SarA protein phosphorylation that impaired SarA binding to the mecA promoter element and downregulated virulence genes such as those encoding biofilm, α-hemolysin, and adhesin. Perturbation of SarA-mecA binding thus interfered with PBP2a biosynthesis and this decreased MRSA resistance to β-lactams. Furthermore, CIN fully restored the anti-MRSA activities of β-lactam antibiotics in vivo in murine models of bacteremia and biofilm infections. Together, our results indicated that CIN acts as a β-lactam adjuvant and can be applied as an alternative therapy to combat multidrug-resistant MRSA infections.
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Affiliation(s)
- Jianguo Li
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Tingyin Lu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yuefei Chu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yuejun Zhang
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Jing Zhang
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
- Yantai Fushan Center for Animal Disease Control and PreventionYantaiChina
| | - Wenzhen Fu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Jian Sun
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yahong Liu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Xiao‐Ping Liao
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yu‐Feng Zhou
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
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Kerro Dego O, Vidlund J. Staphylococcal mastitis in dairy cows. Front Vet Sci 2024; 11:1356259. [PMID: 38863450 PMCID: PMC11165426 DOI: 10.3389/fvets.2024.1356259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/06/2024] [Indexed: 06/13/2024] Open
Abstract
Bovine mastitis is one of the most common diseases of dairy cattle. Even though different infectious microorganisms and mechanical injury can cause mastitis, bacteria are the most common cause of mastitis in dairy cows. Staphylococci, streptococci, and coliforms are the most frequently diagnosed etiological agents of mastitis in dairy cows. Staphylococci that cause mastitis are broadly divided into Staphylococcus aureus and non-aureus staphylococci (NAS). NAS is mainly comprised of coagulase-negative Staphylococcus species (CNS) and some coagulase-positive and coagulase-variable staphylococci. Current staphylococcal mastitis control measures are ineffective, and dependence on antimicrobial drugs is not sustainable because of the low cure rate with antimicrobial treatment and the development of resistance. Non-antimicrobial effective and sustainable control tools are critically needed. This review describes the current status of S. aureus and NAS mastitis in dairy cows and flags areas of knowledge gaps.
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Affiliation(s)
- Oudessa Kerro Dego
- Department of Animal Science, University of Tennessee, Knoxville, TN, United States
| | - Jessica Vidlund
- Department of Animal Science, University of Tennessee, Knoxville, TN, United States
- East Tennessee AgResearch and Education Center-Little River Animal and Environmental Unit, University of Tennessee, Walland, TN, United States
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3
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Campbell MJ, Beenken KE, Ramirez AM, Smeltzer MS. Increased production of aureolysin and staphopain A is a primary determinant of the reduced virulence of Staphylococcus aureus sarA mutants in osteomyelitis. mBio 2024; 15:e0338323. [PMID: 38415646 PMCID: PMC11005355 DOI: 10.1128/mbio.03383-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/09/2024] [Indexed: 02/29/2024] Open
Abstract
We previously demonstrated that mutation of sarA in Staphylococcus aureus limits biofilm formation, cytotoxicity for osteoblasts and osteoclasts, and virulence in osteomyelitis, and that all of these phenotypes can be attributed to the increased production of extracellular proteases. Here we extend these studies to assess the individual importance of these proteases alone and in combination with each other using the methicillin-resistant USA300 strain LAC, the methicillin-susceptible USA200 strain UAMS-1, and isogenic sarA mutants that were also unable to produce aureolysin (Aur), staphopain A (ScpA), staphylococcal serine protease A (subsp.), staphopain B (SspB), and the staphylococcal serine protease-like proteins A-F (SplA-F). Biofilm formation was restored in LAC and UAMS-1 sarA mutants by subsequent mutation of aur and scpA, while mutation of aur had the greatest impact on cytotoxicity to mammalian cells, particularly with conditioned medium (CM) from the more cytotoxic strain LAC. However, SDS-PAGE and western blot analysis of CM confirmed that mutation of sspAB was also required to mimic the phenotype of sarA mutants unable to produce any extracellular proteases. Nevertheless, in a murine model of post-traumatic osteomyelitis, mutation of aur and scpA had the greatest impact on restoring the virulence of LAC and UAMS-1 sarA mutants, with concurrent mutation of sspAB and the spl operon having relatively little effect. These results demonstrate that the increased production of Aur and ScpA in combination with each other is a primary determinant of the reduced virulence of S. aureus sarA mutants in diverse clinical isolates including both methicillin-resistant and methicillin-susceptible strains.IMPORTANCEPrevious work established that SarA plays a primary role in limiting the production of extracellular proteases to prevent them from limiting the abundance of S. aureus virulence factors. Eliminating the production of all 10 extracellular proteases in the methicillin-resistant strain LAC has also been shown to enhance virulence in a murine sepsis model, and this has been attributed to the specific proteases Aur and ScpA. The importance of this work lies in our demonstration that the increased production of these same proteases largely accounts for the decreased virulence of sarA mutants in a murine model of post-traumatic osteomyelitis not only in LAC but also in the methicillin-susceptible human osteomyelitis isolate UAMS-1. This confirms that sarA-mediated repression of Aur and ScpA production plays a critical role in the posttranslational regulation of S. aureus virulence factors in diverse clinical isolates and diverse forms of S. aureus infection.
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Affiliation(s)
- Mara J. Campbell
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Karen E. Beenken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Aura M. Ramirez
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mark S. Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Campbell MJ, Beenken KE, Spencer HJ, Jayana B, Hester H, Sahukhal GS, Elasri MO, Smeltzer MS. Comparative evaluation of small molecules reported to be inhibitors of Staphylococcus aureus biofilm formation. Microbiol Spectr 2024; 12:e0314723. [PMID: 38059629 PMCID: PMC10782960 DOI: 10.1128/spectrum.03147-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/09/2023] [Indexed: 12/08/2023] Open
Abstract
IMPORTANCE Because biofilm formation is such a problematic feature of Staphylococcus aureus infections, much effort has been put into identifying biofilm inhibitors. However, the results observed with these compounds are often reported in isolation, and the methods used to assess biofilm formation vary between labs, making it impossible to assess relative efficacy and prioritize among these putative inhibitors for further study. The studies we report address this issue by directly comparing putative biofilm inhibitors using a consistent in vitro assay. This assay was previously shown to maximize biofilm formation, and the results observed with this assay have been proven to be relevant in vivo. Of the 19 compounds compared using this method, many had no impact on biofilm formation under these conditions. Indeed, only one proved effective at limiting biofilm formation without also inhibiting growth.
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Affiliation(s)
- Mara J. Campbell
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Karen E. Beenken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Horace J. Spencer
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Bina Jayana
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Hana Hester
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Gyan S. Sahukhal
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mohamed O. Elasri
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mark S. Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Kim JH, Kim YH, Park BI, Choi NY, Kim KJ. Pinus koraiensis Essential Oil Attenuates the Pathogenicity of Superbacteria by Suppressing Virulence Gene Expression. Molecules 2023; 29:37. [PMID: 38202618 PMCID: PMC10779922 DOI: 10.3390/molecules29010037] [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: 10/18/2023] [Revised: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
In the quest to combat infections attributable to antibiotic-resistant superbacteria, an essential oil derived from the needles of Pinus koraiensis Sieb. et Zucc. (PKEO) has emerged as a promising solution. In this study, we demonstrate that PKEO can be used to inhibit the growth, glucose metabolite acidogenicity, and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Quantitative PCR analysis provided direct evidence that PKEO reduces the mRNA expression of the accessory gene regulator A (agrA) and staphylococcal accessory regulator A (sarA), thereby indicating its inhibitory effect on pathogenic regulatory genes. Chromatographic analyses of PKEO identified terpene hydrocarbons as prominent essential oil constituents. These compounds, notably α-pinene, limonene, and β-caryophyllene, have been established to have antimicrobial properties. Our findings indicate that an oil derived from P. koraiensis can effectively combat antibiotic-resistant strains by disrupting the pathogenicity regulatory system, thereby establishing PKEO as a promising candidate for the treatment of MRSA infections.
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Affiliation(s)
- Ji-Hee Kim
- Department of Convergence Technology for Food Industry, Wonkwang University, Iksan 54538, Republic of Korea;
- Transdisciplinary Major in Learning Health Systems, Department of Health and Safety Convergence Science, Graduate School, Korea University, Seoul 02841, Republic of Korea
| | - Young-Hoi Kim
- Department of Food Science and Technology, College of Agriculture and Life Sciences, Jeonbuk National University, Jeonju 54896, Republic of Korea;
| | - Bog-Im Park
- Department of Food and Nutrition, Kunsan National University, Kunsan 54150, Republic of Korea;
| | - Na-Young Choi
- College of Education, Wonkwang University, Iksan 54538, Republic of Korea
| | - Kang-Ju Kim
- Department of Oral Microbiology, School of Dentistry, Wonkwang University, Iksan 54538, Republic of Korea
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Li JG, Chen XF, Lu TY, Zhang J, Dai SH, Sun J, Liu YH, Liao XP, Zhou YF. Increased Activity of β-Lactam Antibiotics in Combination with Carvacrol against MRSA Bacteremia and Catheter-Associated Biofilm Infections. ACS Infect Dis 2023; 9:2482-2493. [PMID: 38019707 DOI: 10.1021/acsinfecdis.3c00338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
β-Lactam antibiotics are the mainstay for the treatment of staphylococcal infections, but their utility is greatly limited by the emergence and rapid dissemination of methicillin-resistant Staphylococcus aureus (MRSA). Herein, we evaluated the ability of the plant-derived monoterpene carvacrol to act as an antibiotic adjuvant, revitalizing the anti-MRSA activity of β-lactam antibiotics. Increased susceptibility of MRSA to β-lactam antibiotics and significant synergistic activities were observed with carvacrol-based combinations. Carvacrol significantly inhibited MRSA biofilms and reduced the production of exopolysaccharide, polysaccharide intercellular adhesin, and extracellular DNA and showed synergistic biofilm inhibition in combination with β-lactams. Transcriptome analysis revealed profound downregulation in the expression of genes involved in two-component systems and S. aureus infection. Mechanistic studies indicate that carvacrol inhibits the expression of staphylococcal accessory regulator sarA and interferes with SarA-mecA promoter binding that decreases mecA-mediated β-lactam resistance. Consistently, the in vivo experiment also supported that carvacrol restored MRSA sensitivity to β-lactam antibiotic treatments in both murine models of bacteremia and biofilm-associated infection. Our results indicated that carvacrol has a potential role as a combinatorial partner with β-lactam antibiotics to address MRSA infections.
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Affiliation(s)
- Jian-Guo Li
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Feng Chen
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Ting-Yin Lu
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Jing Zhang
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
- Yantai Fushan Center for Animal Disease Control and Prevention, Fushan, Yantai, Shandong 265500, China
| | - Shu-He Dai
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Jian Sun
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Ya-Hong Liu
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Xiao-Ping Liao
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Yu-Feng Zhou
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
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Francis D, Veeramanickathadathil Hari G, Koonthanmala Subash A, Bhairaddy A, Joy A. The biofilm proteome of Staphylococcus aureus and its implications for therapeutic interventions to biofilm-associated infections. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 138:327-400. [PMID: 38220430 DOI: 10.1016/bs.apcsb.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Staphylococcus aureus is a major healthcare concern due to its ability to inflict life-threatening infections and evolve antibiotic resistance at an alarming pace. It is frequently associated with hospital-acquired infections, especially device-associated infections. Systemic infections due to S. aureus are difficult to treat and are associated with significant mortality and morbidity. The situation is worsened by the ability of S. aureus to form social associations called biofilms. Biofilms embed a community of cells with the ability to communicate with each other and share resources within a polysaccharide or protein matrix. S. aureus establish biofilms on tissues and conditioned abiotic surfaces. Biofilms are hyper-tolerant to antibiotics and help evade host immune responses. Biofilms exacerbate the severity and recalcitrance of device-associated infections. The development of a biofilm involves various biomolecules, such as polysaccharides, proteins and nucleic acids, contributing to different structural and functional roles. Interconnected signaling pathways and regulatory molecules modulate the expression of these molecules. A comprehensive understanding of the molecular biology of biofilm development would help to devise effective anti-biofilm therapeutics. Although bactericidal agents, antimicrobial peptides, bacteriophages and nano-conjugated anti-biofilm agents have been employed with varying levels of success, there is still a requirement for effective and clinically viable anti-biofilm therapeutics. Proteins that are expressed and utilized during biofilm formation, constituting the biofilm proteome, are a particularly attractive target for anti-biofilm strategies. The proteome can be explored to identify potential anti-biofilm drug targets and utilized for rational drug discovery. With the aim of uncovering the biofilm proteome, this chapter explores the mechanism of biofilm formation and its regulation. Furthermore, it explores the antibiofilm therapeutics targeted against the biofilm proteome.
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Affiliation(s)
- Dileep Francis
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India.
| | | | | | - Anusha Bhairaddy
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India
| | - Atheene Joy
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India
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8
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Patel H, Rawat S. A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis. Front Microbiol 2023; 14:1204428. [PMID: 37434702 PMCID: PMC10332168 DOI: 10.3389/fmicb.2023.1204428] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/30/2023] [Indexed: 07/13/2023] Open
Abstract
Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.
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Affiliation(s)
| | - Seema Rawat
- Microbiology Laboratory, School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India
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9
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Tao Z, Wang H, Ke K, Shi D, Zhu L. Flavone inhibits Staphylococcus aureus virulence via inhibiting the sae two component system. Microb Pathog 2023; 180:106128. [PMID: 37148922 DOI: 10.1016/j.micpath.2023.106128] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/08/2023] [Accepted: 04/26/2023] [Indexed: 05/08/2023]
Abstract
The rising prevalence of antibiotic resistance in Staphylococcus aureus calls for the development of innovative antimicrobial agents targeting novel pathways. S. aureus generates various virulence factors that compromise host defense mechanisms. Flavone, a core structure of flavonoids, has been shown to diminish the production of staphyloxanthin and alpha-hemolysin. Nonetheless, the influence of flavone on the majority of other virulence factors in S. aureus and its underlying molecular mechanism remain elusive. In this study, we examined the impact of flavone on the transcriptional profile of S. aureus using transcriptome sequencing. Our findings revealed that flavone substantially downregulated the expression of over 30 virulence factors implicated in immune evasion by the pathogen. Gene set enrichment analysis of the fold change-ranked gene list in relation to the Sae regulon indicated a robust association between flavone-induced downregulation and membership in the Sae regulon. Through the analysis of Sae target promoter-gfp fusion expression patterns, we observed a dose-dependent inhibition of Sae target promoter activity by flavone. Moreover, we discovered that flavone protected human neutrophils from S. aureus-mediated killing. Flavone also decreased the expression of alpha-hemolysin and other hemolytic toxins, resulting in a reduction in S. aureus' hemolytic capacity. Additionally, our data suggested that the inhibitory effect of flavone on the Sae system operates independently of its capacity to lower staphyloxanthin levels. In conclusion, our study proposes that flavone exhibits a broad inhibitory action on multiple virulence factors of S. aureus by targeting the Sae system, consequently diminishing the bacterium's pathogenicity.
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Affiliation(s)
- Zhanhua Tao
- Institute of Eco-Environmental Research, Guangxi Academy of Sciences, Nanning, 530003, Guangxi, China; Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Nanning, 530003, Guangxi, China.
| | - Haoren Wang
- The First Affiliated Hospital of Jiamusi University, Jiamusi, 154002, Heilongjiang, China.
| | - Ke Ke
- Guangxi Academy of Sciences, Nanning, 530003, Guangxi, China.
| | - Deqiang Shi
- Guangxi Academy of Sciences, Nanning, 530003, Guangxi, China.
| | - Libo Zhu
- Guangxi Academy of Sciences, Nanning, 530003, Guangxi, China.
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10
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Peng Q, Tang X, Dong W, Sun N, Yuan W. A Review of Biofilm Formation of Staphylococcus aureus and Its Regulation Mechanism. Antibiotics (Basel) 2022; 12:antibiotics12010012. [PMID: 36671212 PMCID: PMC9854888 DOI: 10.3390/antibiotics12010012] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.
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Affiliation(s)
- Qi Peng
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Xiaohua Tang
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Wanyang Dong
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Ning Sun
- Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
| | - Wenchang Yuan
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
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11
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Alkam D, Jenjaroenpun P, Ramirez AM, Beenken KE, Spencer HJ, Smeltzer MS. The Increased Accumulation of Staphylococcus aureus Virulence Factors Is Maximized in a purR Mutant by the Increased Production of SarA and Decreased Production of Extracellular Proteases. Infect Immun 2021; 89:e00718-20. [PMID: 33468580 PMCID: PMC8090970 DOI: 10.1128/iai.00718-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/14/2021] [Indexed: 01/18/2023] Open
Abstract
Mutation of purR was previously shown to enhance the virulence of Staphylococcus aureus in a murine sepsis model, and this cannot be fully explained by increased expression of genes within the purine biosynthesis pathway. Rather, the increased production of specific S. aureus virulence factors, including alpha toxin and the fibronectin-binding proteins, was shown to play an important role. Mutation of purR was also shown previously to result in increased abundance of SarA. Here, we demonstrate by transposon sequencing that mutation of purR in the USA300 strain LAC increases fitness in a biofilm while mutation of sarA has the opposite effect. Therefore, we assessed the impact of sarA on reported purR-associated phenotypes by characterizing isogenic purR, sarA, and sarA/purR mutants. The results confirmed that mutation of purR results in increased abundance of alpha toxin, protein A, the fibronectin-binding proteins, and SarA, decreased production of extracellular proteases, an increased capacity to form a biofilm, and increased virulence in an osteomyelitis model. Mutation of sarA had the opposite effects on all of these phenotypes and, other than bacterial burdens in the bone, all of the phenotypes of sarA/purR mutants were comparable to those of sarA mutants. Limiting the production of extracellular proteases reversed all of the phenotypes of sarA mutants and most of those of sarA/purR mutants. We conclude that a critical component defining the virulence of a purR mutant is the enhanced production of SarA, which limits protease production to an extent that promotes the accumulation of critical S. aureus virulence factors.
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Affiliation(s)
- Duah Alkam
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Piroon Jenjaroenpun
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Aura M Ramirez
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Karen E Beenken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Horace J Spencer
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mark S Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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12
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Saeed K, Sendi P, Arnold WV, Bauer TW, Coraça-Huber DC, Chen AF, Choe H, Daiss JL, Ghert M, Hickok NJ, Nishitani K, Springer BD, Stoodley P, Sculco TP, Brause BD, Parvizi J, McLaren AC, Schwarz EM. Bacterial toxins in musculoskeletal infections. J Orthop Res 2021; 39:240-250. [PMID: 32255540 PMCID: PMC7541548 DOI: 10.1002/jor.24683] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/27/2020] [Accepted: 04/01/2020] [Indexed: 02/04/2023]
Abstract
Musculoskeletal infections (MSKIs) remain a major health burden in orthopaedics. Bacterial toxins are foundational to pathogenesis in MSKI, but poorly understood by the community of providers that care for patients with MSKI, inducing an international group of microbiologists, infectious diseases specialists, orthopaedic surgeons and biofilm scientists to review the literature in this field to identify key topics and compile the current knowledge on the role of toxins in MSKI, with the goal of illuminating potential impact on biofilm formation and dispersal as well as therapeutic strategies. The group concluded that further research is needed to maximize our understanding of the effect of toxins on MSKIs, including: (i) further research to identify the roles of bacterial toxins in MSKIs, (ii) establish the understanding of the importance of environmental and host factors and in vivo expression of toxins throughout the course of an infection, (iii) establish the principles of drug-ability of antitoxins as antimicrobial agents in MSKIs, (iv) have well-defined metrics of success for antitoxins as antiinfective drugs, (v) design a cocktail of antitoxins against specific pathogens to (a) inhibit biofilm formation and (b) inhibit toxin release. The applicability of antitoxins as potential antimicrobials in the era of rising antibiotic resistance could meet the needs of day-to-day clinicians.
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Affiliation(s)
- Kordo Saeed
- University Hospital Southampton NHS Foundation Trust, Department of Microbiology, Microbiology Innovation and Research Unit (MIRU), Southampton, UK; and University of Southampton, School of Medicine, Southampton UK
| | - Parham Sendi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Infectious Diseases and Hospital Epidemiology/ Department of Orthopaedics and Traumatology, University Hospital Basel, University Basel, Basel, Switzerland
| | - William V. Arnold
- Department of Orthopaedic Surgery, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Thomas W. Bauer
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Hospital for Special Surgery, New York, NY, USA
| | - Débora C. Coraça-Huber
- Research Laboratory for Implant Associated Infections (Biofilm Lab), Experimental Orthopaedics, Department of Orthopaedic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Antonia F. Chen
- Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Hyonmin Choe
- Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Kanagawa, Japan
| | - John L. Daiss
- Center for Musculoskeletal Research, School of Medicine and Dentistry University of Rochester, Rochester, NY, USA
| | - Michelle Ghert
- Department of Surgery, Division of Orthopaedic Surgery, McMaster University, Hamilton, ON, Canada
| | - Noreen J. Hickok
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, USA
| | - Kohei Nishitani
- Department of Orthopaedic Surgery, Kyoto University, Kyoto, Japan
| | - Bryan D. Springer
- OrthoCarolina Hip and Knee Center, Atrium Musculoskeletal Institute, Charlotte, NC, USA
| | - Paul Stoodley
- Departments of Microbial Infection and Immunity and OrthopedicsInfectious Diseases Institute, The Ohio State University, 716 Biomedical Research Tower, 460 West 12th Avenue, Columbus OH, Canada
- National Centre for Microbial Tribology at Southampton (nCATS), National Biofilm Innovation Centre (NBIC), Mechanical Engineering, University of Southampton, Southampton, UK.
| | - Thomas P. Sculco
- Department of Orthopaedic Surgery, Weill Cornell Medicine, Hospital for Special Surgery, New York, NY, USA
| | - Barry D. Brause
- Department of Infectious Diseases, Weill Cornell Medicine, Hospital for Special Surgery, New York, NY, USA
| | - Javad Parvizi
- Department of Orthopaedics, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Alex C. McLaren
- Department of Orthopaedic Surgery, University of Arizona, College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Edward M. Schwarz
- Center for Musculoskeletal Research, Department of Orthopaedics, University of Rochester, Rochester, NY, USA
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13
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Petrie LE, Leonard AC, Murphy J, Cox G. Development and validation of a high-throughput whole cell assay to investigate Staphylococcus aureus adhesion to host ligands. J Biol Chem 2020; 295:16700-16712. [PMID: 32978256 PMCID: PMC7864066 DOI: 10.1074/jbc.ra120.015360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/22/2020] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus adhesion to the host's skin and mucosae enables asymptomatic colonization and the establishment of infection. This process is facilitated by cell wall-anchored adhesins that bind to host ligands. Therapeutics targeting this process could provide significant clinical benefits; however, the development of anti-adhesives requires an in-depth knowledge of adhesion-associated factors and an assay amenable to high-throughput applications. Here, we describe the development of a sensitive and robust whole cell assay to enable the large-scale profiling of S. aureus adhesion to host ligands. To validate the assay, and to gain insight into cellular factors contributing to adhesion, we profiled a sequence-defined S. aureus transposon mutant library, identifying mutants with attenuated adhesion to human-derived fibronectin, keratin, and fibrinogen. Our screening approach was validated by the identification of known adhesion-related proteins, such as the housekeeping sortase responsible for covalently linking adhesins to the cell wall. In addition, we also identified genetic loci that could represent undescribed anti-adhesive targets. To compare and contrast the genetic requirements of adhesion to each host ligand, we generated a S. aureus Genetic Adhesion Network, which identified a core gene set involved in adhesion to all three host ligands, and unique genetic signatures. In summary, this assay will enable high-throughput chemical screens to identify anti-adhesives and our findings provide insight into the target space of such an approach.
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Affiliation(s)
- Laurenne E Petrie
- College of Biological Sciences, Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Allison C Leonard
- College of Biological Sciences, Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Julia Murphy
- College of Biological Sciences, Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Georgina Cox
- College of Biological Sciences, Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
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14
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Ramirez AM, Beenken KE, Byrum SD, Tackett AJ, Shaw LN, Gimza BD, Smeltzer MS. SarA plays a predominant role in controlling the production of extracellular proteases in the diverse clinical isolates of Staphylococcus aureus LAC and UAMS-1. Virulence 2020; 11:1738-1762. [PMID: 33258416 PMCID: PMC7738309 DOI: 10.1080/21505594.2020.1855923] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/12/2020] [Accepted: 11/18/2020] [Indexed: 12/26/2022] Open
Abstract
Using DNA affinity chromatography we demonstrate that the S. aureus regulatory proteins MgrA, Rot, SarA, and SarS bind DNA baits derived from the promoter regions associated with the genes encoding aureolysin, ScpAB, SspABC, and SplA-F. Three of four baits also bound SarR and SarZ, the exception in both cases being the ScpAB-associated bait. Using the USA300, methicillin-resistant strain LAC and the USA200, methicillin-sensitive strain UAMS-1, we generated mutations in the genes encoding each of these proteins alone and in combination with sarA and examined the impact on protease production, the accumulation of high molecular weight proteins, and biofilm formation. These studies confirmed that multiple regulatory loci are involved in limiting protease production to a degree that impacts all of these phenotypes, but also demonstrate that sarA plays a predominant role in this regard. Using sarA mutants unable to produce individual proteases alone and in combination with each other, we also demonstrate that the increased production of aureolysin and ScpA is particularly important in defining the biofilm-deficient phenotype of LAC and UAMS-1 sarA mutants, while aureolysin alone plays a key role in defining the reduced accumulation of alpha toxin and overall cytotoxicity as assessed using both osteoblasts and osteoclasts.
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Affiliation(s)
- Aura M. Ramirez
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Karen E. Beenken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Stephanie D. Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, and Arkansas Children’s Research Institute, Little Rock, AR, USA
| | - Alan J. Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, and Arkansas Children’s Research Institute, Little Rock, AR, USA
| | - Lindsey N. Shaw
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL
| | - Brittney D. Gimza
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL
| | - Mark S. Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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15
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Sahukhal GS, Tucci M, Benghuzzi H, Wilson G, Elasri MO. The role of the msaABCR operon in implant-associated chronic osteomyelitis in Staphylococcus aureus USA300 LAC. BMC Microbiol 2020; 20:324. [PMID: 33109085 PMCID: PMC7590495 DOI: 10.1186/s12866-020-01964-8] [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: 10/31/2019] [Accepted: 09/02/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The msaABCR operon regulates several staphylococcal phenotypes such as biofilm formation, capsule production, protease production, pigmentation, antibiotic resistance, and persister cells formation. The msaABCR operon is required for maintaining the cell wall integrity via affecting peptidoglycan cross-linking. The msaABCR operon also plays a role in oxidative stress defense mechanism, which is required to facilitate persistent and recurrent staphylococcal infections. Staphylococcus aureus is the most frequent cause of chronic implant-associated osteomyelitis (OM). The CA-MRSA USA300 strains are predominant in the United States and cause severe infections, including bone and joint infections. RESULTS The USA300 LAC strain caused significant bone damage, as evidenced by the presence of severe bone necrosis with multiple foci of sequestra and large numbers of multinucleated osteoclasts. Intraosseous survival and biofilm formation on the K-wires by USA300 LAC strains was pronounced. However, the msaABCR deletion mutant was attenuated. We observed minimal bone necrosis, with no evidence of intramedullary abscess and/or fibrosis, along reduced intraosseous bacterial population and significantly less biofilm formation on the K-wires by the msaABCR mutant. microCT analysis of infected bone showed significant bone loss and damage in the USA300 LAC and complemented strain, whereas the msaABCR mutant's effect was reduced. In addition, we observed increased osteoblasts response and new bone formation around the K-wires in the bone infected by the msaABCR mutant. Whole-cell proteomics analysis of msaABCR mutant cells showed significant downregulation of proteins, cell adhesion factors, and virulence factors that interact with osteoblasts and are associated with chronic OM caused by S. aureus. CONCLUSION This study showed that deletion of msaABCR operon in USA300 LAC strain lead to defective biofilm in K-wire implants, decreased intraosseous survival, and reduced cortical bone destruction. Thus, msaABCR plays a role in implant-associated chronic osteomyelitis by regulating extracellular proteases, cell adhesions factors and virulence factors. However additional studies are required to further define the contribution of msaABCR-regulated molecules in osteomyelitis pathogenesis.
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Affiliation(s)
- Gyan S Sahukhal
- Present Address: Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406, USA.
| | - Michelle Tucci
- Department of Orthopaedics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Hamed Benghuzzi
- Department of Orthopaedics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Gerri Wilson
- Department of Orthopaedics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Mohamed O Elasri
- Present Address: Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406, USA
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16
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Salzer A, Keinhörster D, Kästle C, Kästle B, Wolz C. Small Alarmone Synthetases RelP and RelQ of Staphylococcus aureus Are Involved in Biofilm Formation and Maintenance Under Cell Wall Stress Conditions. Front Microbiol 2020; 11:575882. [PMID: 33072039 PMCID: PMC7533549 DOI: 10.3389/fmicb.2020.575882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/25/2020] [Indexed: 12/15/2022] Open
Abstract
The stringent response is characterized by the synthesis of the alarmone (p)ppGpp. The phenotypic consequences resulting from (p)ppGpp accumulation vary among species, and for several pathogenic bacteria, it has been shown that the activation of the stringent response strongly affects biofilm formation and maintenance. In Staphylococcus aureus, (p)ppGpp can be synthesized by the RelA/SpoT homolog Rel upon amino acid deprivation or by the two small alarmone synthetases RelP and RelQ under cell wall stress. We found that relP and relQ increase biofilm formation under cell wall stress conditions induced by a subinhibitory vancomycin concentration. However, the effect of (p)ppGpp on biofilm formation is independent of the regulators CodY and Agr. Biofilms formed by the strain HG001 or its (p)ppGpp-defective mutants are mainly composed of extracellular DNA and proteins. Furthermore, the induction of the RelPQ-mediated stringent response contributes to biofilm-related antibiotic tolerance. The proposed (p)ppGpp-inhibiting peptide DJK-5 shows bactericidal and biofilm-inhibitory activity. However, a non-(p)ppGpp-producing strain is even more vulnerable to DJK-5. This strongly argues against the assumption that DJK-5 acts via (p)ppGpp inhibition. In summary, RelP and RelQ play a major role in biofilm formation and maintenance under cell wall stress conditions.
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Affiliation(s)
| | | | | | | | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
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17
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020; 84:e00026-19. [PMID: 32792334 PMCID: PMC7430342 DOI: 10.1128/mmbr.00026-19] [Citation(s) in RCA: 302] [Impact Index Per Article: 75.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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18
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19/asset/e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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19
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Forson AM, van der Mei HC, Sjollema J. Impact of solid surface hydrophobicity and micrococcal nuclease production on Staphylococcus aureus Newman biofilms. Sci Rep 2020; 10:12093. [PMID: 32694559 PMCID: PMC7374737 DOI: 10.1038/s41598-020-69084-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/02/2020] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is commonly associated with biofilm-related infections and contributes to the large financial loss that accompany nosocomial infections. The micrococcal nuclease Nuc1 enzyme limits biofilm formation via cleavage of eDNA, a structural component of the biofilm matrix. Solid surface hydrophobicity influences bacterial adhesion forces and may as well influence eDNA production. Therefore, it is hypothesized that the impact of Nuc1 activity is dependent on surface characteristics of solid surfaces. For this reason, this study investigated the influence of solid surface hydrophobicity on S. aureus Newman biofilms where Nuc1 is constitutively produced. To this end, biofilms of both a wild-type and a nuc1 knockout mutant strain, grown on glass, salinized glass and Pluronic F-127-coated silanized glass were analysed. Results indicated that biofilms can grow in the presence of Nuc1 activity. Also, Nuc1 and solid surface hydrophobicity significantly affected the biofilm 3D-architecture. In particular, biofilm densities of the wild-type strain on hydrophilic surfaces appeared higher than of the mutant nuc1 knockout strain. Since virulence is related to bacterial cell densities, this suggests that the virulence of S. aureus Newman biofilms is increased by its nuclease production in particular on a hydrophilic surface.
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Affiliation(s)
- Abigail M Forson
- University of Groningen, University Medical Centre Groningen, Department of Biomedical Engineering, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Henny C van der Mei
- University of Groningen, University Medical Centre Groningen, Department of Biomedical Engineering, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Jelmer Sjollema
- University of Groningen, University Medical Centre Groningen, Department of Biomedical Engineering, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
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20
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SpoVG Modulates Cell Aggregation in Staphylococcus aureus by Regulating sasC Expression and Extracellular DNA Release. Appl Environ Microbiol 2020; 86:AEM.00591-20. [PMID: 32444467 PMCID: PMC7376557 DOI: 10.1128/aem.00591-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/06/2020] [Indexed: 11/20/2022] Open
Abstract
This study revealed that SpoVG can modulate cell aggregation by repressing sasC expression and extracellular DNA (eDNA) release. Furthermore, we have demonstrated the potential linkage between cell aggregation and antibiotic resistance. Our findings provide novel insights into the regulatory mechanisms of SpoVG involved in cell aggregation and in biofilm development and formation in Staphylococcus aureus. Biofilm formation is involved in numerous Staphylococcus aureus infections such as endocarditis, septic arthritis, osteomyelitis, and infections of indwelling medical devices. In these diseases, S. aureus forms biofilms as cell aggregates interspersed in host matrix material. Here, we have observed that the level of cell aggregation was significantly higher in the isogenic spoVG-deletion strain than in the wild-type strain. Reverse transcription-quantitative PCR data indicated that SpoVG could repress the expression of sasC, which codes for S. aureus surface protein C and is involved in cell aggregation and biofilm accumulation. Electromagnetic mobility shift assay demonstrated that SpoVG could specifically bind to the promoter region of sasC, indicating that SpoVG is a negative regulator and directly represses the expression of sasC. In addition, deletion of the SasC aggregation domain in the spoVG-deletion strain indicated that high-level expression of sasC could be the underlying cause of significantly increased cell aggregation formation. Our previous study showed that SpoVG is involved in oxacillin resistance of methicillin-resistant S. aureus by regulating the expression of genes involved in cell wall synthesis and degradation. In this study, we also found that SpoVG was able to negatively modulate the S. aureus drug tolerance under conditions of a high concentration of oxacillin treatment. These findings can broaden our understanding of the regulation of biofilm formation and drug tolerance in S. aureus. IMPORTANCE This study revealed that SpoVG can modulate cell aggregation by repressing sasC expression and extracellular DNA (eDNA) release. Furthermore, we have demonstrated the potential linkage between cell aggregation and antibiotic resistance. Our findings provide novel insights into the regulatory mechanisms of SpoVG involved in cell aggregation and in biofilm development and formation in Staphylococcus aureus.
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21
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Vollaro A, Esposito A, Esposito EP, Zarrilli R, Guaragna A, De Gregorio E. PYED-1 Inhibits Biofilm Formation and Disrupts the Preformed Biofilm of Staphylococcus aureus. Antibiotics (Basel) 2020; 9:E240. [PMID: 32397205 PMCID: PMC7277567 DOI: 10.3390/antibiotics9050240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
Pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1 (PYED-1), a heterocyclic corticosteroid derivative of deflazacort, exhibits broad-spectrum antibacterial activity against Gram-negative and Gram-positive bacteria. Here, we investigated the effect of PYED-1 on the biofilms of Staphylococcus aureus, an etiological agent of biofilm-based chronic infections such as osteomyelitis, indwelling medical device infections, periodontitis, chronic wound infections, and endocarditis. PYED-1 caused a strong reduction in biofilm formation in a concentration dependent manner. Furthermore, it was also able to completely remove the preformed biofilm. Transcriptional analysis performed on the established biofilm revealed that PYED-1 downregulates the expression of genes related to quorum sensing (agrA, RNAIII, hld, psm, and sarA), surface proteins (clfB and fnbB), secreted toxins (hla, hlb, and lukD), and capsular polysaccharides (capC). The expression of genes that encode two main global regulators, sigB and saeR, was also significantly inhibited after treatment with PYED-1. In conclusion, PYED-1 not only effectively inhibited biofilm formation, but also eradicated preformed biofilms of S. aureus, modulating the expression of genes related to quorum sensing, surface and secreted proteins, and capsular polysaccharides. These results indicated that PYED-1 may have great potential as an effective antibiofilm agent to prevent S. aureus biofilm-associated infections.
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Affiliation(s)
- Adriana Vollaro
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy;
| | - Anna Esposito
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy;
| | - Eliana Pia Esposito
- Department of Public Health, University of Naples Federico II, 80131 Naples, Italy; (E.P.E.); (R.Z.)
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, 80131 Naples, Italy; (E.P.E.); (R.Z.)
| | - Annalisa Guaragna
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy;
| | - Eliana De Gregorio
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy;
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22
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Ramirez AM, Byrum SD, Beenken KE, Washam C, Edmondson RD, Mackintosh SG, Spencer HJ, Tackett AJ, Smeltzer MS. Exploiting Correlations between Protein Abundance and the Functional Status of saeRS and sarA To Identify Virulence Factors of Potential Importance in the Pathogenesis of Staphylococcus aureus Osteomyelitis. ACS Infect Dis 2020; 6:237-249. [PMID: 31722523 PMCID: PMC7294808 DOI: 10.1021/acsinfecdis.9b00291] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We used a murine model of postsurgical osteomyelitis (OM) to evaluate the relative virulence of the Staphylococcus aureus strain LAC and five isogenic variants that differ in the functional status of saeRS and sarA relative to each other. LAC and a variant in which saeRS activity is increased (saeC) were comparably virulent to each other, while ΔsaeRS, ΔsarA, ΔsaeRS/ΔsarA, and saeC/ΔsarA mutants were all attenuated to a comparable degree. Phenotypic comparisons including a mass-based proteomics approach that allowed us to assess the number and abundance of full-length proteins suggested that mutation of saeRS attenuates virulence in our OM model owing primarily to the decreased production of S. aureus virulence factors, while mutation of sarA does so owing to protease-mediated degradation of these same virulence factors. This was confirmed by demonstrating that eliminating protease production restored virulence to a greater extent in a LAC sarA mutant than in the isogenic saeRS mutant. Irrespective of the mechanism involved, mutation of saeRS or sarA was shown to result in reduced accumulation of virulence factors of potential importance. Thus, using our proteomics approach we correlated the abundance of specific proteins with virulence in these six strains and identified 14 proteins that were present in a significantly increased amount (log2 ≥ 5.0) in both virulent strains by comparison to all four attenuated strains. We examined biofilm formation and virulence in our OM model using a LAC mutant unable to produce one of these 14 proteins, specifically staphylocoagulase. The results confirmed that mutation of coa limits biofilm formation and, to a lesser extent, virulence in our OM model, although in both cases the limitation was reduced by comparison to the isogenic sarA mutant.
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Affiliation(s)
- Aura M. Ramirez
- Department of Microbiology
and Immunology, College of Medicine, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 511, Little Rock, Arkansas 72205, United States
| | - Stephanie D. Byrum
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 516, Little Rock, Arkansas 72205, United States,Arkansas
Children’s Research Institute, 1 Children’s Way, Little Rock, Arkansas 72202, United States
| | - Karen E. Beenken
- Department of Microbiology
and Immunology, College of Medicine, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 511, Little Rock, Arkansas 72205, United States
| | - Charity Washam
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 516, Little Rock, Arkansas 72205, United States,Arkansas
Children’s Research Institute, 1 Children’s Way, Little Rock, Arkansas 72202, United States
| | - Rick D. Edmondson
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 516, Little Rock, Arkansas 72205, United States
| | - Samuel G. Mackintosh
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 516, Little Rock, Arkansas 72205, United States
| | - Horace J. Spencer
- Department of Biostatistics, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, Arkansas 72205, United States
| | - Alan J. Tackett
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 516, Little Rock, Arkansas 72205, United States,Arkansas
Children’s Research Institute, 1 Children’s Way, Little Rock, Arkansas 72202, United States
| | - Mark S. Smeltzer
- Department of Microbiology
and Immunology, College of Medicine, University
of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 511, Little Rock, Arkansas 72205, United States,Department
of Orthopaedic Surgery, University of Arkansas
for Medical Sciences, 4301 W. Markham Street, Slot 531, Little Rock, Arkansas 72205, United States,Phone: 501-686-7958. E-mail:
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23
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The Impacts of msaABCR on sarA-Associated Phenotypes Are Different in Divergent Clinical Isolates of Staphylococcus aureus. Infect Immun 2020; 88:IAI.00530-19. [PMID: 31740526 PMCID: PMC6977130 DOI: 10.1128/iai.00530-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022] Open
Abstract
The staphylococcal accessory regulator (sarA) plays an important role in Staphylococcus aureus infections, including osteomyelitis, and the msaABCR operon has been implicated as an important factor in modulating expression of sarA Thus, we investigated the contribution of msaABCR to sarA-associated phenotypes in the S. aureus clinical isolates LAC and UAMS-1. Mutation of msaABCR resulted in reduced production of SarA and a reduced capacity to form a biofilm in both strains. Biofilm formation was enhanced in a LAC msa mutant by restoring the production of SarA, but this was not true in a UAMS-1 msa mutant. Similarly, extracellular protease production was increased in a LAC msa mutant but not a UAMS-1 msa mutant. This difference was reflected in the accumulation and distribution of secreted virulence factors and in the impact of extracellular proteases on biofilm formation in a LAC msa mutant. Most importantly, it was reflected in the relative impact of mutating msa as assessed in a murine osteomyelitis model, which had a significant impact in LAC but not in UAMS-1. In contrast, mutation of sarA had a greater impact on all of these in vitro and in vivo phenotypes than mutation of msaABCR, and it did so in both LAC and UAMS-1. These results suggest that, at least in osteomyelitis, it would be therapeutically preferable to target sarA rather than msaABCR to achieve the desired clinical result, particularly in the context of divergent clinical isolates of S. aureus.
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24
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Stochastic Expression of Sae-Dependent Virulence Genes during Staphylococcus aureus Biofilm Development Is Dependent on SaeS. mBio 2020; 11:mBio.03081-19. [PMID: 31937649 PMCID: PMC6960292 DOI: 10.1128/mbio.03081-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The intricate process of biofilm formation in the human pathogen Staphylococcus aureus involves distinct stages during which a complex mixture of matrix molecules is produced and modified throughout the developmental cycle. Early in biofilm development, a subpopulation of cells detaches from its substrate in an event termed "exodus" that is mediated by SaePQRS-dependent stochastic expression of a secreted staphylococcal nuclease, which degrades extracellular DNA within the matrix, causing the release of cells and subsequently allowing for the formation of metabolically heterogenous microcolonies. Since the SaePQRS regulatory system is involved in the transcriptional control of multiple S. aureus virulence factors, the expression of several additional virulence genes was examined within a developing biofilm by introducing fluorescent gene reporter plasmids into wild-type S. aureus and isogenic regulatory mutants and growing these strains in a microfluidic system that supplies the bacteria with a constant flow of media while simultaneously imaging developing biofilms in 5-min intervals. This study demonstrated that multiple virulence genes, including nuc, were expressed stochastically within a specialized subpopulation of cells in nascent biofilms. We demonstrated that virulence genes regulated by SaePQRS were stochastically expressed in nearly all strains examined whereas Agr-regulated genes were expressed more homogenously within maturing microcolonies. The commonly used Newman strain contains a variant of SaeS (SaeSP) that confers constitutive kinase activity to the protein and caused this strain to lack the stochastic expression pattern observed in other strain backgrounds. Importantly, repair of the SaeSP allele resulting in reversion to the well-conserved SaeS L allele found in other strains restored stochastic expression in this strain.IMPORTANCE Staphylococcus aureus is an important human pathogen capable of colonizing diverse tissue types and inducing severe disease in both immunocompromised and otherwise healthy individuals. Biofilm infections caused by this bacterial species are of particular concern because of their persistence, even in the face of intensive therapeutic intervention. The results of the current study demonstrate the stochastic nature of Sae-mediated virulence gene expression in S. aureus and indicate that this regulatory system may function as a "bistable switch" in a manner similar to that seen with regulators controlling competence gene expression in Bacillus subtilis and persister cell formation in Escherichia coli The results of this study provide a new perspective on the complex mechanisms utilized by S. aureus during the establishment of infections.
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25
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Gudeta DD, Lei MG, Lee CY. Contribution of hla Regulation by SaeR to Staphylococcus aureus USA300 Pathogenesis. Infect Immun 2019; 87:e00231-19. [PMID: 31209148 PMCID: PMC6704604 DOI: 10.1128/iai.00231-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/11/2019] [Indexed: 02/08/2023] Open
Abstract
The SaeRS two-component system in Staphylococcus aureus is critical for regulation of many virulence genes, including hla, which encodes alpha-toxin. However, the impact of regulation of alpha-toxin by Sae on S. aureus pathogenesis has not been directly addressed. Here, we mutated the SaeR-binding sequences in the hla regulatory region and determined the contribution of this mutation to hla expression and pathogenesis in strain USA300 JE2. Western blot analyses revealed drastic reduction of alpha-toxin levels in the culture supernatants of SaeR-binding mutant in contrast to the marked alpha-toxin production in the wild type. The SaeR-binding mutation had no significant effect on alpha-toxin regulation by Agr, MgrA, and CcpA. In animal studies, we found that the SaeR-binding mutation did not contribute to USA300 JE2 pathogenesis using a rat infective endocarditis model. However, in a rat skin and soft tissue infection model, the abscesses on rats infected with the mutant were significantly smaller than the abscesses on those infected with the wild type but similar to the abscesses on those infected with a saeR mutant. These studies indicated that there is a direct effect of hla regulation by SaeR on pathogenesis but that the effect depends on the animal model used.
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Affiliation(s)
- Dereje D Gudeta
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mei G Lei
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Chia Y Lee
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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26
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Azmi K, Qrei W, Abdeen Z. Screening of genes encoding adhesion factors and biofilm production in methicillin resistant strains of Staphylococcus aureus isolated from Palestinian patients. BMC Genomics 2019; 20:578. [PMID: 31299899 PMCID: PMC6624993 DOI: 10.1186/s12864-019-5929-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/24/2019] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Intercellular adhesion and biofilm production by Staphylococcus aureus makes these bacteria resistant to antimicrobial therapy. Here, Methicillin-resistant Staphylococcus aureus (MRSA) strains were characterized and the prevalence of genes encoding adhesion factors and biofilm formation was determined. RESULTS All 248 MRSA isolates identified by cefoxitin disc diffusion were positive for the mecA gene. SCCmec-IV was the most frequently detected genotype (92.7%) and SCCmec-IVa was also very prevalent (84.3%). The quantitative microtiter plate assay showed that all the isolates were able to produce biofilm with levels ranging from high (21%) to moderate (46.4%) to low (32.7%). All the strains possessed the icaD/icaA genes and produced biofilm (P < 0.05). None of the isolates possessed the bap gene. Furthermore, 94.8% of the isolates were positive for eno, 80.2% for clfA and for clfB, 78.2% for fnbA, 76.2% for ebps, 62.2% for fib, 39.9% for cna and 29.0% for fnbB. Also, nearly 69.8% of the isolates were positive for the gene sarA. All four agr groups were present: agr group 1 was predominant with 39.5%; agr group 3. agr group 2 and 3 strains carried more toxin-producing genes, and frequently produced more toxin. Sixty-six (26.6%) of the strains were multidrug resistant. All were vancomycin sensitive. Agr group I is more resistant to ciprofloxacin and gentamicin while agr group III is more resistant to erythromycin. Maximum sensitivity was to gentamicin and SXT, and they could be considered drugs of choice for controlling MRSA mediated infections in this region. CONCLUSIONS Biofilm development in MRSA might be an ica dependent and one needs to investigate the involvement of other global regulators, agr and sarA, and their contribution to the biofilm phenotype, as the high rate of biofilm production among the studied strains of S. aureus.
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Affiliation(s)
- Kifaya Azmi
- Biochemistry and Molecular Biology Department, Al-Quds Nutrition and Health Research Institute, Faculty of Medicine, Al-Quds University, Abu Deis, The West Bank, Palestine. .,Al-Quds Public Health Society, Jerusalem, Palestine. .,Faculty of Medicine, Al-Quds Nutrition and Health Research Institute, Al-Quds University, Abu-Deis, P.O. Box 20760, The West Bank, Palestine.
| | - Walaa Qrei
- Al-Quds Public Health Society, Jerusalem, Palestine
| | - Ziad Abdeen
- Al-Quds Public Health Society, Jerusalem, Palestine.,Faculty of Medicine, Al-Quds Nutrition and Health Research Institute, Al-Quds University, Abu-Deis, P.O. Box 20760, The West Bank, Palestine
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27
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Graf AC, Leonard A, Schäuble M, Rieckmann LM, Hoyer J, Maass S, Lalk M, Becher D, Pané-Farré J, Riedel K. Virulence Factors Produced by Staphylococcus aureus Biofilms Have a Moonlighting Function Contributing to Biofilm Integrity. Mol Cell Proteomics 2019; 18:1036-1053. [PMID: 30850421 PMCID: PMC6553939 DOI: 10.1074/mcp.ra118.001120] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/19/2019] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is the causative agent of various biofilm-associated infections in humans causing major healthcare problems worldwide. This type of infection is inherently difficult to treat because of a reduced metabolic activity of biofilm-embedded cells and the protective nature of a surrounding extracellular matrix (ECM). However, little is known about S. aureus biofilm physiology and the proteinaceous composition of the ECM. Thus, we cultivated S. aureus biofilms in a flow system and comprehensively profiled intracellular and extracellular (ECM and flow-through (FT)) biofilm proteomes, as well as the extracellular metabolome compared with planktonic cultures. Our analyses revealed the expression of many pathogenicity factors within S. aureus biofilms as indicated by a high abundance of capsule biosynthesis proteins along with various secreted virulence factors, including hemolysins, leukotoxins, and lipases as a part of the ECM. The activity of ECM virulence factors was confirmed in a hemolysis assay and a Galleria mellonella pathogenicity model. In addition, we uncovered a so far unacknowledged moonlighting function of secreted virulence factors and ribosomal proteins trapped in the ECM: namely their contribution to biofilm integrity. Mechanistically, it was revealed that this stabilizing effect is mediated by the strong positive charge of alkaline virulence factors and ribosomal proteins in an acidic ECM environment, which is caused by the release of fermentation products like formate, lactate, and acetate because of oxygen limitation in biofilms. The strong positive charge of these proteins most likely mediates electrostatic interactions with anionic cell surface components, eDNA, and anionic metabolites. In consequence, this leads to strong cell aggregation and biofilm stabilization. Collectively, our study identified a new molecular mechanism during S. aureus biofilm formation and thus significantly widens the understanding of biofilm-associated S. aureus infections - an essential prerequisite for the development of novel antimicrobial therapies.
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Affiliation(s)
- Alexander C Graf
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Anne Leonard
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Manuel Schäuble
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Lisa M Rieckmann
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Juliane Hoyer
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Sandra Maass
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Michael Lalk
- §Institute of Biochemistry, Department of Cellular Biochemistry and Metabolomics
| | - Dörte Becher
- ¶Institute of Microbiology, Department of Microbial Proteomics; University of Greifswald, Germany
| | - Jan Pané-Farré
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology
| | - Katharina Riedel
- From the ‡Institute of Microbiology, Department of Microbial Physiology and Molecular Biology;
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28
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Hall JW, Lima BP, Herbomel GG, Gopinath T, McDonald L, Shyne MT, Lee JK, Kreth J, Ross KF, Veglia G, Herzberg MC. An intramembrane sensory circuit monitors sortase A-mediated processing of streptococcal adhesins. Sci Signal 2019; 12:12/580/eaas9941. [PMID: 31064885 DOI: 10.1126/scisignal.aas9941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial adhesins mediate adhesion to substrates and biofilm formation. Adhesins of the LPXTG family are posttranslationally processed by the cell membrane-localized peptidase sortase A, which cleaves the LPXTG motif. This generates a short C-terminal peptide (C-pep) that remains in the cell membrane, whereas the mature adhesin is incorporated into the cell wall. Genes encoding adhesins of the oral bacterium Streptococcus gordonii were differentially expressed depending on whether the bacteria were isolated from saliva or dental plaque and appeared to be coordinately regulated. Deletion of sspA and sspB (sspAB), both of which encode LPXTG-containing adhesins, unexpectedly enhanced adhesion and biofilm formation. C-peps produced from a model LPXTG-containing adhesin localized to the cell membrane and bound to and inhibited the intramembrane sensor histidine kinase SGO_1180, thus preventing activation of the cognate response regulator SGO_1181. The absence of SspAB C-peps induced the expression of the scaCBA operon encoding the lipoprotein adhesin ScaA, which was sufficient to preserve and even enhance biofilm formation. This C-pep-driven regulatory circuit also exists in pathogenic streptococci and is likely conserved among Gram-positive bacteria. This quality control mechanism ensures that the bacteria can form biofilms under diverse environmental conditions and may play a role in optimizing adhesion and biofilm formation.
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Affiliation(s)
- Jeffrey W Hall
- Department of Biological and Diagnostic Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bruno P Lima
- Department of Biological and Diagnostic Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Tata Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - LeAnna McDonald
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael T Shyne
- Biostatistical Design and Analysis Center (BDAC), Clinical and Translational Science Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - John K Lee
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Karen F Ross
- Department of Biological and Diagnostic Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark C Herzberg
- Department of Biological and Diagnostic Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
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29
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Abstract
Staphylococcus aureus is one of the most important human pathogens that is responsible for a variety of diseases ranging from skin and soft tissue infections to endocarditis and sepsis. In recent decades, the treatment of staphylococcal infections has become increasingly difficult as the prevalence of multi-drug resistant strains continues to rise. With increasing mortality rates and medical costs associated with drug resistant strains, there is an urgent need for alternative therapeutic options. Many innovative strategies for alternative drug development are being pursued, including disruption of biofilms, inhibition of virulence factor production, bacteriophage-derived antimicrobials, anti-staphylococcal vaccines, and light-based therapies. While many compounds and methods still need further study to determine their feasibility, some are quickly approaching clinical application and may be available in the near future.
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30
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Abstract
Staphylococci, with the leading species Staphylococcus aureus and Staphylococcus epidermidis, are the most frequent causes of infections on indwelling medical devices. The biofilm phenotype that those bacteria adopt during device-associated infection facilitates increased resistance to antibiotics and host immune defenses. This review presents and discusses the molecular mechanisms contributing to staphylococcal biofilm development and their in-vivo importance. Furthermore, it summarizes current strategies for the development of therapeutics against staphylococcal biofilm-associated infection.
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31
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De Backer S, Sabirova J, De Pauw I, De Greve H, Hernalsteens JP, Goossens H, Malhotra-Kumar S. Enzymes Catalyzing the TCA- and Urea Cycle Influence the Matrix Composition of Biofilms Formed by Methicillin-Resistant Staphylococcus aureus USA300. Microorganisms 2018; 6:microorganisms6040113. [PMID: 30380651 PMCID: PMC6313315 DOI: 10.3390/microorganisms6040113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/17/2018] [Accepted: 10/25/2018] [Indexed: 11/21/2022] Open
Abstract
In methicillin-sensitive Staphylococcus aureus (MSSA), the tricarboxylic acid (TCA) cycle is known to negatively regulate production of the major biofilm-matrix exopolysaccharide, PIA/PNAG. However, methicillin-resistant S. aureus (MRSA) produce a primarily proteinaceous biofilm matrix, and contribution of the TCA-cycle therein remains unclear. Utilizing USA300-JE2 Tn-mutants (NARSA) in genes encoding TCA- and urea cycle enzymes for transduction into a prolific biofilm-forming USA300 strain (UAS391-Erys), we studied the contribution of the TCA- and urea cycle and of proteins, eDNA and PIA/PNAG, to the matrix. Genes targeted in the urea cycle encoded argininosuccinate lyase and arginase (argH::Tn and rocF::Tn), and in the TCA-cycle encoded succinyl-CoA synthetase, succinate dehydrogenase, aconitase, isocitrate dehydrogenase, fumarate hydratase class II, and citrate synthase II (sucC::Tn, sdhA/B::Tn, acnA::Tn, icd::Tn, fumC::Tn and gltA::Tn). Biofilm formation was significantly decreased under no flow and flow conditions by argH::Tn, fumC::Tn, and sdhA/B::Tn (range OD492 0.374−0.667; integrated densities 2.065−4.875) compared to UAS391-EryS (OD492 0.814; integrated density 10.676) (p ≤ 0.008). Cellular and matrix stains, enzymatic treatment (Proteinase K, DNase I), and reverse-transcriptase PCR-based gene-expression analysis of fibronectin-binding proteins (fnbA/B) and the staphylococcal accessory regulator (sarA) on pre-formed UAS391-Erys and Tn-mutant biofilms showed: (i) < 1% PIA/PNAG in the proteinaceous/eDNA matrix; (ii) increased proteins under no flow and flow in the matrix of Tn mutant biofilms (on average 50 and 51 (±11)%) compared to UAS391-Erys (on average 22 and 25 (±4)%) (p < 0.001); and (iii) down- and up-regulation of fnbA/B and sarA, respectively, in Tn-mutants compared to UAS391-EryS (0.62-, 0.57-, and 2.23-fold on average). In conclusion, we show that the biofilm matrix of MRSA-USA300 and the corresponding Tn mutants is PIA/PNAG-independent and are mainly composed of proteins and eDNA. The primary impact of TCA-cycle inactivation was on the protein component of the biofilm matrix of MRSA-USA300.
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Affiliation(s)
- Sarah De Backer
- Department of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Julia Sabirova
- Department of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Ines De Pauw
- Department of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Henri De Greve
- Structural & Molecular Microbiology, VIB-VUB Center for Structural Biology, 1050 Brussels, Belgium.
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
| | | | - Herman Goossens
- Department of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Surbhi Malhotra-Kumar
- Department of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, 2610 Wilrijk, Belgium.
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32
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Byrum S, Loughran AJ, Beenken KE, Orr LM, Storey AJ, Mackintosh SG, Edmondson RD, Tackett AJ, Smeltzer MS. Label-Free Proteomic Approach to Characterize Protease-Dependent and -Independent Effects of sarA Inactivation on the Staphylococcus aureus Exoproteome. J Proteome Res 2018; 17:3384-3395. [PMID: 30209945 PMCID: PMC6209314 DOI: 10.1021/acs.jproteome.8b00288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The staphylococcal accessory regulator A ( sarA) impacts the extracellular accumulation of Staphylococcus aureus virulence factors at the level of intracellular production and extracellular protease-mediated degradation. We previously used a proteomics approach that measures protein abundance of all proteoforms to demonstrate that mutation of sarA results in increased levels of extracellular proteases and assesses the impact of this on the accumulation of S. aureus exoproteins. Our previous approach was limited as it did not take into account that large, stable proteolytic products from a given protein could result in false negatives when quantified by total proteoforms. Here, our goal was to use an expanded proteomics approach utilizing a dual quantitative method for measuring abundance at both the total proteoform and full-length exoprotein levels to alleviate these false negatives and thereby provide for characterization of protease-dependent and -independent effects of sarA mutation on the S. aureus exoproteome. Proteins present in conditioned medium from overnight, stationary phase cultures of the USA300 strain LAC, an isogenic sarA mutant, and a sarA mutant unable to produce any of the known extracellular proteases ( sarA/protease) were resolved using one-dimensional gel electrophoresis. Quantitative proteomic comparisons of sarA versus sarA/protease mutants identified proteins that were cleaved in a protease-dependent manner owing to mutation of sarA, and comparisons of sarA/protease mutant versus the LAC parent strain identified proteins in which abundance was altered in a sarA mutant in a protease-independent manner. Furthermore, the proteins uniquely identified by the full-length data analysis approach eliminated false negatives observed in the total proteoform analysis. This expanded approach provided for a more comprehensive analysis of the impact of mutating sarA on the S. aureus exoproteome.
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Affiliation(s)
- Stephanie
D. Byrum
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States,Arkansas
Children’s Research Institute, 13 Children’s Way, Little Rock, Arkansas 72202, United States
| | - Allister J. Loughran
- Department
of Microbiology and Immunology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Karen E. Beenken
- Department
of Microbiology and Immunology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Lisa M. Orr
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Aaron J. Storey
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Samuel G. Mackintosh
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Ricky D. Edmondson
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States
| | - Alan J. Tackett
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States,Arkansas
Children’s Research Institute, 13 Children’s Way, Little Rock, Arkansas 72202, United States,E-mail:
| | - Mark S. Smeltzer
- Department
of Microbiology and Immunology, University
of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, United States,E-mail: , Phone: (501) 686-7958
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33
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Wermser C, Lopez D. Identification of Staphylococcus aureus genes involved in the formation of structured macrocolonies. MICROBIOLOGY-SGM 2018; 164:801-815. [PMID: 29638209 DOI: 10.1099/mic.0.000660] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The human pathogen Staphylococcus aureus causes difficult-to-eradicate biofilm-associated infections that generally become chronic. Understanding the genetic regulation of biofilm formation in S. aureus is central to a precise definition of the conditions and genes involved in development of chronic biofilm-associated infections. Biofilm-related genes have been detected by comparing mutants using the classical submerged biofilm formation assay, in which cells adhere to the bottom of a well containing culture medium. We recently developed an alternative biofilm formation model for S. aureus, based on macrocolony formation on agar plates, comparable to an assay used to study biofilm formation in a few other bacterial species. As organism features are the result of environmental conditions as well as of genes, we used a genome-wide collection of transposon-mapped mutants in this macrocolony assay to seek S. aureus developmental genes and pathways not identified by the classical biofilm formation assay. We identified routes related to glucose and purine metabolism and clarified their regulatory link to macrocolony formation. Our study demonstrates that formation of microbial communities must be correlated to specific growth conditions, and the role of metabolism must be considered in S. aureus biofilm formation and thus, in the development of chronic infections.
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Affiliation(s)
- Charlotte Wermser
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany.,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany
| | - Daniel Lopez
- Research Centre for Infectious Diseases (ZINF), University of Würzburg, Würzburg 97080, Germany.,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg 97080, Germany.,National Centre for Biotechnology, Spanish National Research Council (CNB-CSIC), Madrid 28049, Spain
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34
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Balamurugan P, Praveen Krishna V, Bharath D, Lavanya R, Vairaprakash P, Adline Princy S. Staphylococcus aureus Quorum Regulator SarA Targeted Compound, 2-[(Methylamino)methyl]phenol Inhibits Biofilm and Down-Regulates Virulence Genes. Front Microbiol 2017; 8:1290. [PMID: 28744275 PMCID: PMC5504099 DOI: 10.3389/fmicb.2017.01290] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/27/2017] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus is a widely acknowledged Gram-positive pathogen for forming biofilm and virulence gene expressions by quorum sensing (QS), a cell to cell communication process. The quorum regulator SarA of S. aureus up-regulates the expression of many virulence factors including biofilm formation to mediate pathogenesis and evasion of the host immune system in the late phases of growth. Thus, inhibiting the production or blocking SarA protein might influence the down-regulation of biofilm and virulence factors. In this context, here we have synthesized 2-[(Methylamino)methyl]phenol, which was specifically targeted toward the quorum regulator SarA through in silico approach in our previous study. The molecule has been evaluated in vitro to validate its antibiofilm activity against clinical S. aureus strains. In addition, antivirulence properties of the inhibitor were confirmed with the observation of a significant reduction in the expression of representative virulence genes like fnbA, hla and hld that are governed under S. aureus QS. Interestingly, the SarA targeted inhibitor showed negligible antimicrobial activity and markedly reduced the minimum inhibitory concentration of conventional antibiotics when used in combination making it a more attractive lead for further clinical tests.
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Affiliation(s)
- P Balamurugan
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
| | - V Praveen Krishna
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
| | - D Bharath
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
| | - Raajaraam Lavanya
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
| | - Pothiappan Vairaprakash
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
| | - S Adline Princy
- Quorum Sensing Laboratory, Centre for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA UniversityThanjavur, India
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Silva LN, Da Hora GCA, Soares TA, Bojer MS, Ingmer H, Macedo AJ, Trentin DS. Myricetin protects Galleria mellonella against Staphylococcus aureus infection and inhibits multiple virulence factors. Sci Rep 2017; 7:2823. [PMID: 28588273 PMCID: PMC5460262 DOI: 10.1038/s41598-017-02712-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/18/2017] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen related to a variety of life-threatening infections but for which antimicrobial resistance is liming the treatment options. We report here that myricetin, but not its glycosylated form, can remarkably decrease the production of several S. aureus virulence factors, including adhesion, biofilm formation, hemolysis and staphyloxanthin production, without interfering with growth. Myricetin affects both surface proteins and secreted proteins which indicate that its action is unrelated to inhibition of the agr quorum sensing system. Analysis of virulence related gene expression and computational simulations of pivotal proteins involved in pathogenesis demonstrate that myricetin downregulates the saeR global regulator and interacts with sortase A and α-hemolysin. Furthermore, Myr confers a significant degree of protection against staphylococcal infection in the Galleria mellonella model. The present findings reveal the potential of Myr as an alternative multi-target antivirulence candidate to control S. aureus pathogenicity.
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Affiliation(s)
- L N Silva
- Centro de Biotecnologia do Estado do Rio Grande do Sul, Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 91501-970, Brazil
- Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 90610-000, Brazil
| | - G C A Da Hora
- Departmento de Química Fundamental, Universidade Federal de Pernambuco, Recife-PE, 50670-901, Brazil
| | - T A Soares
- Departmento de Química Fundamental, Universidade Federal de Pernambuco, Recife-PE, 50670-901, Brazil
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden
| | - M S Bojer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, 1870, Denmark
| | - H Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, 1870, Denmark
| | - A J Macedo
- Centro de Biotecnologia do Estado do Rio Grande do Sul, Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 91501-970, Brazil.
- Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 90610-000, Brazil.
| | - D S Trentin
- Centro de Biotecnologia do Estado do Rio Grande do Sul, Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 91501-970, Brazil
- Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, 90610-000, Brazil
- Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre-RS, 90050-170, Brazil
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36
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Moormeier DE, Bayles KW. Staphylococcus aureus biofilm: a complex developmental organism. Mol Microbiol 2017; 104:365-376. [PMID: 28142193 DOI: 10.1111/mmi.13634] [Citation(s) in RCA: 291] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 12/11/2022]
Abstract
Chronic biofilm-associated infections caused by Staphylococcus aureus often lead to significant increases in morbidity and mortality, particularly when associated with indwelling medical devices. This has triggered a great deal of research attempting to understand the molecular mechanisms that control S. aureus biofilm formation and the basis for the recalcitrance of these multicellular structures to antibiotic therapy. The purpose of this review is to summarize our current understanding of S. aureus biofilm development, focusing on the description of a newly-defined, five-stage model of biofilm development and the mechanisms required for each stage. Importantly, this model includes an alternate view of the processes involved in microcolony formation in S. aureus and suggests that these structures originate as a result of stochastically regulated metabolic heterogeneity and proliferation within a maturing biofilm population, rather than a subtractive process involving the release of cell clusters from a thick, unstructured biofilm. Importantly, it is proposed that this new model of biofilm development involves the genetically programmed generation of metabolically distinct subpopulations of cells, resulting in an overall population that is better able to adapt to rapidly changing environmental conditions.
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Affiliation(s)
- Derek E Moormeier
- Center for Staphylococcal Research, Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kenneth W Bayles
- Center for Staphylococcal Research, Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
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Figueiredo AMS, Ferreira FA, Beltrame CO, Côrtes MF. The role of biofilms in persistent infections and factors involved in ica-independent biofilm development and gene regulation in Staphylococcus aureus. Crit Rev Microbiol 2017; 43:602-620. [PMID: 28581360 DOI: 10.1080/1040841x.2017.1282941] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Staphylococcus aureus biofilms represent a unique micro-environment that directly contribute to the bacterial fitness within hospital settings. The accumulation of this structure on implanted medical devices has frequently caused the development of persistent and chronic S. aureus-associated infections, which represent an important social and economic burden worldwide. ica-independent biofilms are composed of an assortment of bacterial products and modulated by a multifaceted and overlapping regulatory network; therefore, biofilm composition can vary among S. aureus strains. In the microniches formed by biofilms-produced by a number of bacterial species and composed by different structural components-drug refractory cell subpopulations with distinct physiological characteristics can emerge and result in therapeutic failures in patients with recalcitrant bacterial infections. In this review, we highlight the importance of biofilms in the development of persistence and chronicity in some S. aureus diseases, the main molecules associated with ica-independent biofilm development and the regulatory mechanisms that modulate ica-independent biofilm production, accumulation, and dispersion.
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Affiliation(s)
- Agnes Marie Sá Figueiredo
- a Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
| | - Fabienne Antunes Ferreira
- b Departamento de Microbiologia, Imunologia e Parasitologia , Campus Universitário Setor F, Bloco A. Florianópolis, Universidade Federal de Santa Catarina , Florianopolis , Brazil
| | - Cristiana Ossaille Beltrame
- a Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
| | - Marina Farrel Côrtes
- a Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
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VfrB Is a Key Activator of the Staphylococcus aureus SaeRS Two-Component System. J Bacteriol 2017; 199:JB.00828-16. [PMID: 28031278 DOI: 10.1128/jb.00828-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 12/22/2022] Open
Abstract
In previous studies, we identified the fatty acid kinase virulence factor regulator B (VfrB) as a potent regulator of α-hemolysin and other virulence factors in Staphylococcus aureus In this study, we demonstrated that VfrB is a positive activator of the SaeRS two-component regulatory system. Analysis of vfrB, saeR, and saeS mutant strains revealed that VfrB functions in the same pathway as SaeRS. At the transcriptional level, the promoter activities of SaeRS class I (coa) and class II (hla) target genes were downregulated during the exponential growth phase in the vfrB mutant, compared to the wild-type strain. In addition, saePQRS expression was decreased in the vfrB mutant strain, demonstrating a need for this protein in the autoregulation of SaeRS. The requirement for VfrB-mediated activation was circumvented when SaeS was constitutively active due to an SaeS (L18P) substitution. Furthermore, activation of SaeS via human neutrophil peptide 1 (HNP-1) overcame the dependence on VfrB for transcription from class I Sae promoters. Consistent with the role of VfrB in fatty acid metabolism, hla expression was decreased in the vfrB mutant with the addition of exogenous myristic acid. Lastly, we determined that aspartic acid residues D38 and D40, which are predicted to be key to VfrB enzymatic activity, were required for VfrB-mediated α-hemolysin production. Collectively, this study implicates VfrB as a novel accessory protein needed for the activation of SaeRS in S. aureusIMPORTANCE The SaeRS two-component system is a key regulator of virulence determinant production in Staphylococcus aureus Although the regulon of this two-component system is well characterized, the activation mechanisms, including the specific signaling molecules, remain elusive. Elucidating the complex regulatory circuit of SaeRS regulation is important for understanding how the system contributes to disease causation by this pathogen. To this end, we have identified the fatty acid kinase VfrB as a positive regulatory modulator of SaeRS-mediated transcription of virulence factors in S. aureus In addition to describing a new regulatory aspect of SaeRS, this study establishes a link between fatty acid kinase activity and virulence factor regulation.
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The Staphylococcus aureus AirSR Two-Component System Mediates Reactive Oxygen Species Resistance via Transcriptional Regulation of Staphyloxanthin Production. Infect Immun 2017; 85:IAI.00838-16. [PMID: 27872240 DOI: 10.1128/iai.00838-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/18/2016] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus is an important opportunistic pathogen and is the etiological agent of many hospital- and community-acquired infections. The golden pigment, staphyloxanthin, of S. aureus colonies distinguishes it from other staphylococci and related Gram-positive cocci. Staphyloxanthin is the product of a series of biosynthetic steps that produce a unique membrane-embedded C30 golden carotenoid and is an important antioxidant. We observed that a strain with an inducible airR overexpression cassette had noticeably increased staphyloxanthin production compared to the wild-type strain under aerobic culturing conditions. Further analysis revealed that depletion or overproduction of the AirR response regulator resulted in a corresponding decrease or increase in staphyloxanthin production and susceptibility to killing by hydrogen peroxide, respectively. Furthermore, the genetic elimination of staphyloxanthin during AirR overproduction abolished the protective phenotype of increased staphyloxanthin production in a whole-blood survival assay. Promoter reporter and gel shift assays determined that the AirR response regulator is a direct positive regulator of the staphyloxanthin-biosynthetic operon, crtOPQMN, but is epistatic to alternative sigma factor B. Taken together, these data indicate that AirSR positively regulates the staphyloxanthin-biosynthetic operon crtOPQMN, promoting survival of S. aureus in the presence of oxidants.
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40
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Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus. PLoS One 2016; 11:e0168305. [PMID: 28005941 PMCID: PMC5179057 DOI: 10.1371/journal.pone.0168305] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 11/30/2016] [Indexed: 02/04/2023] Open
Abstract
Staphylococcus aureus is a serious human pathogen and antibiotic resistant, community-associated strains, such as the methicillin resistant S. aureus (MRSA) strain USA300, continue to spread. To avoid resistance, anti-virulence therapy has been proposed where toxicity is targeted rather than viability. Previously we have shown that norlichexanthone, a small non-reduced tricyclic polyketide produced by fungi and lichens, reduces expression of hla encoding α-hemolysin as well as the regulatory RNAIII of the agr quorum sensing system in S. aureus 8325-4. The aim of the present study was to further characterise the mode of action of norlichexanthone and its effect on biofilm formation. We find that norlichexanthone reduces expression of both hla and RNAIII also in strain USA300. Structurally, norlichexanthone resembles ω-hydroxyemodin that recently was shown to bind the agr two component response regulator, AgrA, which controls expression of RNAIII and the phenol soluble modulins responsible for human neutrophil killing. We show that norlichexanthone reduces S. aureus toxicity towards human neutrophils and interferes directly with AgrA binding to its DNA target. In contrast to ω-hydroxyemodin however, norlichexanthone reduces staphylococcal biofilm formation. Transcriptomic analysis revealed that genes regulated by the SaeRS two-component system are repressed by norlichexanthone when compared to untreated cells, an effect that was mitigated in strain Newman carrying a partially constitutive SaeRS system. Our data show that norlichexanthone treatment reduces expression of key virulence factors in CA-MRSA strain USA300 via AgrA binding and represses biofilm formation.
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41
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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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42
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Liu Q, Yeo WS, Bae T. The SaeRS Two-Component System of Staphylococcus aureus. Genes (Basel) 2016; 7:genes7100081. [PMID: 27706107 PMCID: PMC5083920 DOI: 10.3390/genes7100081] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/23/2016] [Indexed: 12/20/2022] Open
Abstract
In the Gram-positive pathogenic bacterium Staphylococcus aureus, the SaeRS twocomponent system (TCS) plays a major role in controlling the production of over 20 virulence factors including hemolysins, leukocidins, superantigens, surface proteins, and proteases. The SaeRS TCS is composed of the sensor histidine kinase SaeS, response regulator SaeR, and two auxiliary proteins SaeP and SaeQ. Since its discovery in 1994, the sae locus has been studied extensively, and its contributions to staphylococcal virulence and pathogenesis have been well documented and understood; however, the molecular mechanism by which the SaeRS TCS receives and processes cognate signals is not. In this article, therefore, we review the literature focusing on the signaling mechanism and its interaction with other global regulators.
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Affiliation(s)
- Qian Liu
- Department of Laboratory Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.
| | - Won-Sik Yeo
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.
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43
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Impact of sarA and Phenol-Soluble Modulins on the Pathogenesis of Osteomyelitis in Diverse Clinical Isolates of Staphylococcus aureus. Infect Immun 2016; 84:2586-94. [PMID: 27354444 DOI: 10.1128/iai.00152-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/18/2016] [Indexed: 12/21/2022] Open
Abstract
We used a murine model of acute, posttraumatic osteomyelitis to evaluate the virulence of two divergent Staphylococcus aureus clinical isolates (the USA300 strain LAC and the USA200 strain UAMS-1) and their isogenic sarA mutants. The results confirmed that both strains caused comparable degrees of osteolysis and reactive new bone formation in the acute phase of osteomyelitis. Conditioned medium (CM) from stationary-phase cultures of both strains was cytotoxic to cells of established cell lines (MC3TC-E1 and RAW 264.7 cells), primary murine calvarial osteoblasts, and bone marrow-derived osteoclasts. Both the cytotoxicity of CM and the reactive changes in bone were significantly reduced in the isogenic sarA mutants. These results confirm that sarA is required for the production and/or accumulation of extracellular virulence factors that limit osteoblast and osteoclast viability and that thereby promote bone destruction and reactive bone formation during the acute phase of S. aureus osteomyelitis. Proteomic analysis confirmed the reduced accumulation of multiple extracellular proteins in the LAC and UAMS-1 sarA mutants. Included among these were the alpha class of phenol-soluble modulins (PSMs), which were previously implicated as important determinants of osteoblast cytotoxicity and bone destruction and repair processes in osteomyelitis. Mutation of the corresponding operon reduced the cytotoxicity of CM from both UAMS-1 and LAC cultures for osteoblasts and osteoclasts. It also significantly reduced both reactive bone formation and cortical bone destruction by CM from LAC cultures. However, this was not true for CM from cultures of a UAMS-1 psmα mutant, thereby suggesting the involvement of additional virulence factors in such strains that remain to be identified.
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44
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Beltrame CO, Côrtes MF, Bandeira PT, Figueiredo AMS. Optimization of the RNeasy Mini Kit to obtain high-quality total RNA from sessile cells of Staphylococcus aureus. ACTA ACUST UNITED AC 2016; 48:1071-6. [PMID: 26517334 PMCID: PMC4661022 DOI: 10.1590/1414-431x20154734] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 07/23/2015] [Indexed: 12/20/2022]
Abstract
Biofilm formed by Staphylococcus aureus is considered an important
virulence trait in the pathogenesis of infections associated with implantable medical
devices. Gene expression analyses are important strategies for determining the
mechanisms involved in production and regulation of biofilm. Obtaining intact RNA
preparations is the first and most critical step for these studies. In this article,
we describe an optimized protocol for obtaining total RNA from sessile cells of
S. aureus using the RNeasy Mini Kit. This method essentially
consists of a few steps, as follows: 1) addition of acetone-ethanol to sessile cells,
2) lysis with lysostaphin at 37°C/10 min, 3) vigorous mixing, 4) three cycles of
freezing and thawing, and 5) purification of the lysate in the RNeasy column. This
simple pre-kit procedure yields high-quality total RNA from planktonic and sessile
cells of S. aureus.
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Affiliation(s)
- C O Beltrame
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - M F Côrtes
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - P T Bandeira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - A M S Figueiredo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
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Ramundo MS, Beltrame CO, Botelho AMN, Coelho LR, Silva-Carvalho MC, Ferreira-Carvalho BT, Nicolás MF, Guedes IA, Dardenne LE, O'Gara J, Figueiredo AMS. A unique SaeS allele overrides cell-density dependent expression of saeR and lukSF-PV in the ST30-SCCmecIV lineage of CA-MRSA. Int J Med Microbiol 2016; 306:367-80. [PMID: 27265234 DOI: 10.1016/j.ijmm.2016.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/06/2016] [Accepted: 05/08/2016] [Indexed: 12/11/2022] Open
Abstract
ST30 (CC30)-SCCmec IV (USA1100) is one of the most common community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) lineages. ST30 isolates typically carry lukSF-PV genes encoding the Panton-Valentine leukocidin (PVL) and are responsible for outbreaks of invasive infections worldwide. In this study, twenty CC30 isolates were analyzed. All were very susceptible to non-β-lactam antimicrobials, 18/20 harbored the lukSF-PV genes, only 1/20 exhibited agr-rnaIII dysfunction, and the majority was not able to form biofilm on inert surfaces. Analysis of lukSF-PV temporal regulation revealed that opposite to other CA-MRSA isolates, these genes were more highly expressed in early log phase than in stationary phase. This inverted lukSF-PV temporal expression was associated with a similar pattern of saeRS expression in the ST30 isolates, namely high level expression in log phase and reduced expression in stationary phase. Reduced saeRS expression in stationary phase was associated with low expression levels of the sae regulators, agr and agr-upregulator sarA, which activate the stationary phase sae-P1 promoter and overexpression of agr-RNAIII restored the levels of saeR and lukSF-PV trancripts in stationary phase. Altered SaeRS activity in the ST30 isolates was attributed to amino acid substitutions (N227S, E268K and S351T) in the HTPase_c domain of SaeS (termed SaeS(SKT)). Complementation of a USA300 saeS mutant with the saeS(SKT) and saeS alleles under the direction of the log phase sae-P3 promoter revealed that saeR and lukSF-PV transcription levels were more significantly activated by saeS(SKT) than saeS. In summary our data identify a unique saeS allele (saeS(SKT)) which appears to override cell-density dependent SaeR and PVL expression in ST30 CA-MRSA isolates. Further studies to determine the contribution of saeS(SKT) allele to the pathogenesis of infections caused by ST30 isolates are merited.
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Affiliation(s)
- Mariana Severo Ramundo
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
| | - Cristiana Ossaille Beltrame
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
| | - Ana Maria Nunes Botelho
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
| | - Leonardo Rocchetto Coelho
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
| | - Maria Cicera Silva-Carvalho
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
| | | | | | | | | | - James O'Gara
- School of Natural Sciences, Microbiology Department, NUI Galway, Galway, Ireland.
| | - Agnes Marie Sá Figueiredo
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, RJ, Brazil.
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XerC Contributes to Diverse Forms of Staphylococcus aureus Infection via agr-Dependent and agr-Independent Pathways. Infect Immun 2016; 84:1214-1225. [PMID: 26857575 DOI: 10.1128/iai.01462-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/02/2016] [Indexed: 02/06/2023] Open
Abstract
We demonstrate that mutation of xerC, which reportedly encodes a homologue of an Escherichia coli recombinase, limits biofilm formation in the methicillin-resistant Staphylococcus aureus strain LAC and the methicillin-sensitive strain UAMS-1. This was not due to the decreased production of the polysaccharide intracellular adhesin (PIA) in either strain because the amount of PIA was increased in a UAMS-1xerC mutant and undetectable in both LAC and its isogenic xerC mutant. Mutation of xerC also resulted in the increased production of extracellular proteases and nucleases in both LAC and UAMS-1, and limiting the production of either class of enzymes increased biofilm formation in the isogenic xerC mutants. More importantly, the limited capacity to form a biofilm was correlated with increased antibiotic susceptibility in both strains in the context of an established biofilm in vivo. Mutation of xerC also attenuated virulence in a murine bacteremia model, as assessed on the basis of the bacterial loads in internal organs and overall lethality. It also resulted in the decreased accumulation of alpha toxin and the increased accumulation of protein A. These findings suggest that xerC may impact the functional status of agr. This was confirmed by demonstrating the reduced accumulation of RNAIII and AgrA in LAC and UAMS-1xerC mutants. However, this cannot account for the biofilm-deficient phenotype of xerC mutants because mutation of agr did not limit biofilm formation in either strain. These results demonstrate that xerC contributes to biofilm-associated infections and acute bacteremia and that this is likely due to agr-independent and -dependent pathways, respectively.
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47
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Yokoi KJ, Kuzuwa S, Iwasaki SI, Yamakawa A, Taketo A, Kodaira KI. Aureolysin of Staphylococcus warneri M accelerates its proteolytic cascade, and participates in biofilm formation. Biosci Biotechnol Biochem 2016; 80:1238-42. [PMID: 27008278 DOI: 10.1080/09168451.2016.1148576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The aureolysin (Aur) gene of S. warneri M (aurWM) was cloned and sequenced. Analyses of the aurWM-inactivated mutant (S. warneri Mau) suggested that AurWM was probably associated with efficient processing of the PROM protease (homolog of V8/SspA serine protease), whereas considerable amount of mature-PROC protease (homolog of SspB cysteine protease) accumulated without AurWM. Additionally, AurWM appeared to affect biofilm formation in an uncertain suppressive way.
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Affiliation(s)
- Ken-Ji Yokoi
- a Food Biochemistry Division , Toyama prefectural Food Research Institute , Toyama , Japan
| | - Shinya Kuzuwa
- b Molecular Biology Group, Faculty of Engineering , Toyama University , Toyama , Japan
| | - Shu-Ichi Iwasaki
- c Quality Control Group , White Food Industry Co. Ltd. , Nanto , Japan
| | - Ayanori Yamakawa
- d Biochemistry Division, Department of Material Science , Wakayama National College of Technology , Wakayama , Japan
| | - Akira Taketo
- e Department of Applied Physics and Chemistry , Fukui University of Technology , Fukui , Japan
| | - Ken-Ichi Kodaira
- b Molecular Biology Group, Faculty of Engineering , Toyama University , Toyama , Japan
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Tranchemontagne ZR, Camire RB, O'Donnell VJ, Baugh J, Burkholder KM. Staphylococcus aureus Strain USA300 Perturbs Acquisition of Lysosomal Enzymes and Requires Phagosomal Acidification for Survival inside Macrophages. Infect Immun 2016; 84:241-53. [PMID: 26502911 PMCID: PMC4694005 DOI: 10.1128/iai.00704-15] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 10/22/2015] [Indexed: 02/08/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) causes invasive, drug-resistant skin and soft tissue infections. Reports that S. aureus bacteria survive inside macrophages suggest that the intramacrophage environment may be a niche for persistent infection; however, mechanisms by which the bacteria might evade macrophage phagosomal defenses are unclear. We examined the fate of the S. aureus-containing phagosome in THP-1 macrophages by evaluating bacterial intracellular survival and phagosomal acidification and maturation and by testing the impact of phagosomal conditions on bacterial viability. Multiple strains of S. aureus survived inside macrophages, and in studies using the MRSA USA300 clone, the USA300-containing phagosome acidified rapidly and acquired the late endosome and lysosome protein LAMP1. However, fewer phagosomes containing live USA300 bacteria than those containing dead bacteria associated with the lysosomal hydrolases cathepsin D and β-glucuronidase. Inhibiting lysosomal hydrolase activity had no impact on intracellular survival of USA300 or other S. aureus strains, suggesting that S. aureus perturbs acquisition of lysosomal enzymes. We examined the impact of acidification on S. aureus intramacrophage viability and found that inhibitors of phagosomal acidification significantly impaired USA300 intracellular survival. Inhibition of macrophage phagosomal acidification resulted in a 30-fold reduction in USA300 expression of the staphylococcal virulence regulator agr but had little effect on expression of sarA, saeR, or sigB. Bacterial exposure to acidic pH in vitro increased agr expression. Together, these results suggest that S. aureus survives inside macrophages by perturbing normal phagolysosome formation and that USA300 may sense phagosomal conditions and upregulate expression of a key virulence regulator that enables its intracellular survival.
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Affiliation(s)
| | - Ryan B Camire
- Department of Nursing, University of New England, Biddeford, Maine, USA
| | | | - Jessfor Baugh
- Department of Biology, University of New England, Biddeford, Maine, USA
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49
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Bhattacharya M, Wozniak DJ, Stoodley P, Hall-Stoodley L. Prevention and treatment of Staphylococcus aureus biofilms. Expert Rev Anti Infect Ther 2015; 13:1499-516. [PMID: 26646248 DOI: 10.1586/14787210.2015.1100533] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
S. aureus colonizes both artificial and tissue surfaces in humans causing chronic persistent infections that are difficult to cure. It is a notorious pathogen due to its antibiotic recalcitrance and phenotypic adaptability, both of which are facilitated by its ability to develop biofilms. S. aureus biofilms challenge conventional anti-infective approaches, most notably antibiotic therapy. Therefore there is an unmet need to develop and include parallel approaches that target S. aureus biofilm infections. This review discusses two broad anti-infective strategies: (1) preventative approaches (anti-biofilm surface coatings, the inclusion of biofilm-specific vaccine antigens); and (2) approaches aimed at eradicating established S. aureus biofilms, particularly those associated with implant infections. Advances in understanding the distinct nature of S. aureus biofilm development and pathogenesis have led to growing optimism in S. aureus biofilm targeted anti-infective strategies. Further research is needed however, to see the successful administration and validation of these approaches to the diverse types of infections caused by S. aureus biofilms from multiple clinical strains.
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Affiliation(s)
- Mohini Bhattacharya
- a Department of Microbiology , The Ohio State University , Columbus , OH , USA
| | - Daniel J Wozniak
- a Department of Microbiology , The Ohio State University , Columbus , OH , USA.,b Department of Microbial Infection and Immunity , The Ohio State University College of Medicine , Columbus , OH , USA.,c The Center for Microbial Interface Biology, The Ohio State University , Columbus , OH , USA
| | - Paul Stoodley
- b Department of Microbial Infection and Immunity , The Ohio State University College of Medicine , Columbus , OH , USA.,c The Center for Microbial Interface Biology, The Ohio State University , Columbus , OH , USA.,d Department of Orthopedics , The Ohio State University College of Medicine , Columbus , OH , USA.,e Department of Engineering Sciences, National Centre for Advanced Tribology at Southampton (nCATS) , University of Southampton , Southampton , UK
| | - Luanne Hall-Stoodley
- b Department of Microbial Infection and Immunity , The Ohio State University College of Medicine , Columbus , OH , USA.,c The Center for Microbial Interface Biology, The Ohio State University , Columbus , OH , USA
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Methicillin-Resistant Staphylococcus aureus Grown on Vancomycin-Supplemented Screening Agar Displays Enhanced Biofilm Formation. Antimicrob Agents Chemother 2015; 59:7906-10. [PMID: 26459889 DOI: 10.1128/aac.00568-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/30/2015] [Indexed: 11/20/2022] Open
Abstract
Brain heart infusion agar containing 3 mg/liter vancomycin (BHI-V3) was used to screen for heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA). There was markedly greater biofilm formation by isolates that grew on BHI-V3 than by strains that did not grow on BHI-V3. Increased biofilm formation by hVISA may be mediated by FnbA- and polysaccharide intercellular adhesin-dependent pathways, and upregulation of atlA and sarA may also contribute to enhanced biofilm formation by hVISA upon prolonged exposure to vancomycin.
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