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Tang W, Liu Y, Li X, Leng G, Gao J, Wang Y, Yao J, Liu Z, Zhou Q, Xu Y. Microbiological Characteristics of Clinically Isolated Staphylococcus aureus with Different Hemolytic Phenotypes in China. Infect Drug Resist 2024; 17:3273-3287. [PMID: 39104458 PMCID: PMC11299731 DOI: 10.2147/idr.s466416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 07/10/2024] [Indexed: 08/07/2024] Open
Abstract
Purpose This study aimed to investigate the microbiological characteristics of clinically isolated Staphylococcus aureus with different hemolytic phenotypes in China. Materials and Methods Using the three-point inoculation method, the hemolytic phenotypes of 1295 clinically isolated S. aureus strains were detected and categorized. Antimicrobial susceptibility testing of all strains was performed using a VITEK 2 Compact System. After sample size matching, plasma coagulase activity, catalase activity, mRNA expression of hemolysin genes (hla, hlb, hlc, and hld), biofilm formation, growth kinetics, inflammatory response of macrophages and cytotoxicity of S. aureus with different hemolytic phenotypes using the rabbit plasma kit, the catalase test on slides, qRT-PCR, crystal violet staining, the microcultivation assay, the ELISA kits, and the CCK-8 assay, respectively. Results Seven categories of hemolytic phenotypes were identified. Accordingly, strains were categorized into seven different groups, including S. aureus with complete hemolytic phenotype (SCHP), S. aureus with weak hemolytic phenotype (SWHP), S. aureus with incomplete hemolytic phenotype 1 (SIHP-1), SIHP-2, SIHP-3, SIHP-4 and SIHP-5, the last three of which were reported for the first time. Except for the hemolytic phenotype, all seven groups differed in clinical isolation rates, antibiotic resistance profile, plasma coagulase activity, mRNA expression of hemolysin genes, biofilm formation, growth kinetics, inflammatory response of macrophages, and cytotoxicity. Conclusion S. aureus with different hemolytic phenotypes have distinctive microbiological characteristics. Clinical microbiologists need to be vigilant about the hemolytic phenotypes when culturing S. aureus strains, and actively enhance communication with clinicians to optimize the treatment of infection.
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Affiliation(s)
- Wei Tang
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People’s Republic of China
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Ying Liu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, People’s Republic of China
| | - Xin Li
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Guiyun Leng
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Ju Gao
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Yawu Wang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Jie Yao
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Zhou Liu
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Qiang Zhou
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China
| | - Yuanhong Xu
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People’s Republic of China
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Wan Y, Wang X, Bai T, Zheng X, Yang L, Li Q, Wang X. Lysine Inhibits Hemolytic Activity of Staphylococcus aureus and Its Application in Food Model Contaminated with Staphylococcus aureus. Toxins (Basel) 2022; 14:toxins14120867. [PMID: 36548764 PMCID: PMC9786064 DOI: 10.3390/toxins14120867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/14/2022] Open
Abstract
Alpha-hemolysin (Hla) is one of the important exotoxins of Staphylococcus aureus (S. aureus) and can be used as a target to reduce the virulence of S. aureus. This study explored the inhibitory effect of Lysine (Lys) on Hla and its application in food safety. Lys significantly inhibited the expression of Hla at sub-inhibitory concentrations and directly interacted with Hla to interfere with its oligomerization and thus significantly inhibited its hemolytic activity. Notably, Lys attenuated S. aureus damage to mouse small intestine and Caco-2 cells and delayed mouse mortality. In the food model, Lys inhibited the expression of Hla of S. aureus and had no significant effect on the sensory score. Moreover, Lys had no obvious damage effect on the main organs of mice, which indicated that Lys has good biocompatibility and has the potential to be used in the food industry as an anti-S. aureus preparation.
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Ghapanvari P, Taheri M, Jalilian FA, Dehbashi S, Dezfuli AAZ, Arabestani MR. The effect of nisin on the biofilm production, antimicrobial susceptibility and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. Eur J Med Res 2022; 27:173. [PMID: 36076252 PMCID: PMC9461124 DOI: 10.1186/s40001-022-00804-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 09/01/2022] [Indexed: 12/03/2022] Open
Abstract
Objectives Staphylococcus aureus and Pseudomonas aeruginosa were the most common bacteria in nosocomial infections. Different bacteriocins are currently being studied as antibiotics or in conjunction with antibiotics as potential strategies to treat resistant infectious agents. The study aimed to determine nisin's effect on the biofilm production, antimicrobial susceptibility, and biofilm formation of S. aureus and P. aeruginosa. Materials and methods The experimental research tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The experimental study tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The MIC of bacteriocin nisin was determined using the micro broth dilution method, and crystal violet was used to assess the effect of bacteriocin on the biofilm. In addition, L929 cell culture was used to determine the effectiveness of bacteriocin on the isolate under similar cell conditions. Moreover, the MTT assay was used to and evaluate bacteriocin toxicity. In this study, the software Prism version 9 and Graph pad software were utilized. Results The results of this study reveal that the nisin has different activities at different doses and is considered dose-dependent. At various times and doses, nisin inhibits biofilm formation in S. aureus, and P. aeruginosa isolates. Nisin also showed a decreasing survival of the isolates. Antibiotic-resistant bacteria can be made more vulnerable by nisin. Furthermore, nisin treatment affected the production of virulence factors such as hemolysins in S. aureus and had little or a negative effect on P. aeruginosa virulence factors. This medication stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage. Conclusions Antibacterial properties of nicin against S. aureus and P. aeruginosa were successfully studied. This bacteriocin stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage or death. Damage to the membrane among the fundamental causes is reduced membrane potential and enzyme inactivation. Supplementary Information The online version contains supplementary material available at 10.1186/s40001-022-00804-x.
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Affiliation(s)
- Parnia Ghapanvari
- Microbiology department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh junction, Hamadan, Iran
| | - Mohammad Taheri
- Microbiology department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh junction, Hamadan, Iran
| | - Farid Aziz Jalilian
- Department of Virology, School of Medicine, University of Hamadan, Pajoohesh junction, Hamadan, Iran
| | - Sanaz Dehbashi
- Microbiology department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh junction, Hamadan, Iran
| | - Aram Asareh Zadegan Dezfuli
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapour University of Medical Sciences, Hamadan, Iran
| | - Mohammad Reza Arabestani
- Microbiology department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh junction, Hamadan, Iran. .,School of Medicine, Nutrition Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
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Gao P, Wei Y, Wan RE, Wong KW, Iu HTV, Tai SSC, Li Y, Yam HCB, Halebeedu Prakash P, Chen JHK, Ho PL, Yuen KY, Davies J, Kao RYT. Subinhibitory Concentrations of Antibiotics Exacerbate Staphylococcal Infection by Inducing Bacterial Virulence. Microbiol Spectr 2022; 10:e0064022. [PMID: 35758685 PMCID: PMC9431598 DOI: 10.1128/spectrum.00640-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/17/2022] [Indexed: 01/24/2023] Open
Abstract
Antibiotics are widely used for the treatment of bacterial infections. However, injudicious use of antibiotics based on an empirical method may lead to the emergence of resistant strains. Despite appropriate administration of antibiotics, their concentrations may remain subinhibitory in the body, due to individual variations in tissue distribution and metabolism rates. This may promote bacterial virulence and complicate the treatment strategies. To investigate whether the administration of certain classes of antibiotics will induce bacterial virulence and worsen the infection under in vivo conditions. Different classes of antibiotics were tested in vitro for their ability to induce virulence in a methicillin-resistant S. aureus strain Mu3 and clinical isolates. Antibiotic-induced pathogenicity was assessed in vivo using mouse peritonitis and bacteremia models. In vitro, β-lactam antibiotics and tetracyclines induced the expression of multiple surface-associated virulence factors as well as the secretion of toxins. In peritonitis and bacteremia models, mice infected with MRSA and treated with ampicillin, ceftazidime, or tetracycline showed enhanced bacterial pathogenicity. The release of induced virulence factors in vivo was confirmed in a histological examination. Subinhibitory concentrations of antibiotics belonging to β-lactam and tetracycline aggravated infection by inducing staphylococcal virulence in vivo. Thus, when antibiotics are required, it is preferable to employ combination therapy and to initiate the appropriate treatment plan, following diagnosis. Our findings emphasize the risks associated with antibiotic-based therapy and underline the need for alternative therapeutic options. IMPORTANCE Antibiotics are widely applied to treat infectious diseases. Empirically treatment with incorrect antibiotics, or even correct antibiotics always falls into subinhibitory concentrations, due to dosing, distribution, or secretion. In this study, we have systematically evaluated in vitro virulence induction effect of antibiotics and in vivo exacerbated infection. The major highlight of this work is to prove the β-lactam and tetracyclines antibiotics exacerbated disease is due to their induction effect on staphylococcal virulence. This phenomenon is common and suggests that if β-lactam antibiotics remain the first line of defense during empirical therapy, we either need to increase patient reliability or the treatment approach may improve in the future when paired with anti-virulence drugs.
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Affiliation(s)
- Peng Gao
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Yuanxin Wei
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Rachel Evelyn Wan
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Ka Wing Wong
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Ho Ting Venice Iu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Sherlock Shing Chiu Tai
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Yongli Li
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Hin Cheung Bill Yam
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Pradeep Halebeedu Prakash
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Jonathan Hon Kwan Chen
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
- Department of Microbiology, Queen Mary Hospital, Pok Fu Lam, Hong Kong
| | - Pak Leung Ho
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
- Department of Microbiology, Queen Mary Hospital, Pok Fu Lam, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases and the Research Centre of Infection and Immunology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Carol Yu Centre for Infection, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Kwok Yung Yuen
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
- Department of Microbiology, Queen Mary Hospital, Pok Fu Lam, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases and the Research Centre of Infection and Immunology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Julian Davies
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Richard Yi Tsun Kao
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases and the Research Centre of Infection and Immunology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
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Hsiung RT, Fang WT, LePage BA, Hsu SA, Hsu CH, Chou JY. In Vitro Properties of Potential Probiotic Indigenous Yeasts Originating from Fermented Food and Beverages in Taiwan. Probiotics Antimicrob Proteins 2021; 13:113-124. [PMID: 32472389 DOI: 10.1007/s12602-020-09661-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Probiotics are live microorganisms that may be able to help prevent and treat some illnesses. Most probiotics on the market are bacterial, primarily Lactobacillus. Yeast are an inevitable part of the microbiota of various fermented foods and beverages and have several beneficial properties that bacteria do not have. In this study, yeast strains were isolated from fermented food and beverages. Various physiological features of the candidate probiotic isolates were preliminarily investigated, including bile salt and acid tolerance, cell surface hydrophobicity, autoaggregation, antioxidant activity, and β-galactosidase activity. Several yeast strains with probiotic potential were selected. Overall, Kluyveromyces marxianus JYC2614 adapted well to the bile salt and acid tolerance test; it also had favorable autoaggregation and good cell-surface hydrophobicity. Klu. marxianus JYC2610 grew well according to the bile salt and acid tolerance test and performed well regarding cell surface hydrophobicity and β-galactosidase activity. Selected yeast species can survive in a gastrointestinal environment and should be further evaluated in vivo as probiotics in the future. Our findings should encourage further studies on the application of the strains in this study as food and feed supplements.
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Affiliation(s)
- Ruo-Ting Hsiung
- Department of Biology, National Changhua University of Education, Changhua, 500, Taiwan
| | - Wei-Ta Fang
- Graduate Institute of Environmental Education, National Taiwan Normal University, Taipei, 116, Taiwan
| | - Ben A LePage
- Pacific Gas and Electric Company, 3401 Crow Canyon Road,, San Ramon, CA, 94583, USA.,Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103, USA
| | - Shih-An Hsu
- Department of Biology, National Changhua University of Education, Changhua, 500, Taiwan
| | - Chia-Hsuan Hsu
- School of Forestry and Resource Conservation, National Taiwan University, Taipei City, 10617, Taiwan
| | - Jui-Yu Chou
- Department of Biology, National Changhua University of Education, Changhua, 500, Taiwan.
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Pandey S, Sahukhal GS, Elasri MO. The msaABCR Operon Regulates Persister Formation by Modulating Energy Metabolism in Staphylococcus aureus. Front Microbiol 2021; 12:657753. [PMID: 33936014 PMCID: PMC8079656 DOI: 10.3389/fmicb.2021.657753] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen that causes chronic, systemic infections, and the recalcitrance of these infections is mainly due to the presence of persister cells, which are a bacterial subpopulation that exhibits extreme, yet transient, antibiotic tolerance accompanied by a transient halt in growth. However, upon cessation of antibiotic treatment, a resumption in growth of persister cells causes recurrence of infections and treatment failure. Previously, we reported the involvement of msaABCR in several important staphylococcal phenotypes, including the formation of persister cells. Additionally, observations of the regulation of several metabolic genes by the msaABCR operon in transcriptomics and proteomics analyses have suggested its role in the metabolic activities of S. aureus. Given the importance of metabolism in persister formation as our starting point, in this study we demonstrated how the msaABCR operon regulates energy metabolism and subsequent antibiotic tolerance. We showed that deletion of the msaABCR operon results in increased tricarboxylic acid (TCA) cycle activity, accompanied by increased cellular ATP content and higher NADH content in S. aureus cells. We also showed that msaABCR (through MsaB) represses the ccpE and ndh2 genes, thereby regulating TCA cycle activity and the generation of membrane potential, respectively. Together, the observations from this study led to the conclusion that msaABCR operon deletion induces a metabolically hyperactive state, leading to decreased persister formation in S. aureus.
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Affiliation(s)
- Shanti Pandey
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Gyan S Sahukhal
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Mohamed O Elasri
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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7
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Feng W, Zhang L, Yuan Q, Wang Y, Yao P, Xia P, Sun F. Effect of sub-minimal inhibitory concentration ceftazidime on the pathogenicity of uropathogenic Escherichia coli. Microb Pathog 2021; 151:104748. [PMID: 33484810 DOI: 10.1016/j.micpath.2021.104748] [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: 10/06/2020] [Revised: 01/04/2021] [Accepted: 01/14/2021] [Indexed: 11/18/2022]
Abstract
Uropathogenic Escherichia coli (UPEC) is the most prevalent causative agent of urinary tract infections (UTIs). The pathogenicity of UPEC relies on the expression of virulence factors which could be regulated by intercellular signal molecules. Our previous study found that sub-minimal inhibitory concentration ceftazidime (sub-MIC CAZ) could inhibit the biofilm formation of E. coli by luxS/AI-2 or indole. Therefore, we speculated that sub-MIC CAZ might affect the pathogenic capacity of UPEC. In this study, the results showed that sub-MIC CAZ could significantly inhibit the adhesion ability, biofilm formation and swimming and swarming motilities of UPEC isolated from recurrent UTI patient. Meanwhile, obvious decreased hemolytic activity and cytotoxicity were observed in CAZ-pretreated UPEC. Furthermore, qRT-PCR results confirmed the downregulating ability of CAZ on the expression of adhesion genes, motility genes, toxin gene and signal molecule synthesis genes, which are important for virulence and biofilm formation of UPEC. Pre-treatment of UPEC with sub-MIC CAZ resulted in the reduced adhesion to human bladder epithelial cell 5637 and the decreased numbers of intracellular bacterial communities in cells. Consistent with the results in vitro, the pretreatment of CAZ resulted in the reduction of UPEC load in the bladder and the less severity of UPEC-induced inflammation compared with control group. The present study results indicated that sub-MIC CAZ could decrease the pathogenicity of UPEC and might be served as an effective antimicrobial agent to combat recurrent UTI caused by UPEC.
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Affiliation(s)
- Wei Feng
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Lei Zhang
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Chongqing Healthcare Security Administration, Chongqing, 401120, China
| | - Qian Yuan
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Yu Wang
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Pu Yao
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Peiyuan Xia
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
| | - Fengjun Sun
- Department of Pharmacy, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
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The Role of Subinhibitory Concentrations of Daptomycin and Tigecycline in Modulating Virulence in Staphylococcus aureus. Antibiotics (Basel) 2021; 10:antibiotics10010039. [PMID: 33401579 PMCID: PMC7823975 DOI: 10.3390/antibiotics10010039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/06/2020] [Accepted: 12/17/2020] [Indexed: 11/28/2022] Open
Abstract
Staphylococcus aureus (S. aureus) infections are notoriously complicated by the ability of the organism to grow in biofilms and are difficult to eradicate with antimicrobial therapy. The purpose of the current study was to clarify the influence of sub-inhibitory concentrations (sub-MICs) of daptomycin and tigecycline antibiotics on biofilm adhesion factors and exoproteins expressions by S. aureus clinical isolates. Six clinical isolates representing positive biofilm S. aureus clones (3 methicillin-sensitive S. aureus (MSSA) and 3 methicillin-resistant S. aureus (MRSA)) were grown with sub-MICs (0.5 MIC) of two antibiotics (daptomycin and tigecycline) for 12 h of incubation. RNA extracted from culture pellets was used via relative quantitative real-time-PCR (qRT-PCR) to determine expression of specific adhesion (fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno) and biofilm (icaADBC) genes. To examine the effect of sub-MIC of these antibiotics on the expression of extracellular proteins, samples from the culture supernatants of six isolates were collected after 12 h of treatment with or without tigecycline in order to profile protein production via 2D gel sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D gel-SDS-PAGE). Sub-MIC treatment of all clinical MRSA and MSSA strains with daptomycin or tigecycline dramatically induced or suppressed fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno, and icaADBC gene expression. Furthermore, sub-MIC use of tigecycline significantly reduced the total number of separated protein spots across all the isolates, as well as decreasing production of certain individual proteins. Collectively, this study showed very different responses in terms of both gene expression and protein secretion across the various isolates. In addition, our results suggest that sub-MIC usage of daptomycin and tigecycline could signal virulence induction by S. aureus via the regulation of biofilm adhesion factor genes and exoproteins. If translating findings to the clinical treatment of S. aureus, the therapeutic regimen should be adapted depending on antibiotic, the virulence factor and strain type.
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Abstract
One of the foremost challenges of drug discovery in any therapeutic area is that of solidifying the correlation between in vitro activity and clinical efficacy. Between these is the confirmation that affecting a particular target in vivo will lead to a therapeutic benefit. In antibacterial drug discovery, there is a key advantage from the start, since the targets are bacteria-therefore, it is simple to ascertain in vitro whether a drug has the desired effect, i.e., bacterial cell inhibition or killing, and to understand the mechanism by which that occurs. The downstream criteria, whether a compound reaches the infection site and achieves appropriately high levels to affect bacterial viability, can be evaluated in animal models of infection. In this way animal models of infection can be a highly valuable and predictive bridge between in vitro drug discovery and early clinical evaluation.The Gram-positive pathogen Staphylococcus aureus causes a wide variety of infections in humans (Archer, Clin Infect Dis 26:1179-1181, 1998), and has been said to be able to infect every tissue type. Fortunately, over the years a great deal of effort has been expended toward developing infection models in rodents using this organism, with good success. This chapter describes the advantages, setups, and outcome measurements of the rodent models most used in drug discovery for S. aureus. Mouse models will be the focus of this chapter, as they are the most economical and thus most commonly used, but a rat infection model is included as well.
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Tang F, Li L, Meng XM, Li B, Wang CQ, Wang SQ, Wang TL, Tian YM. Inhibition of alpha-hemolysin expression by resveratrol attenuates Staphylococcus aureus virulence. Microb Pathog 2019; 127:85-90. [DOI: 10.1016/j.micpath.2018.11.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 11/19/2018] [Accepted: 11/19/2018] [Indexed: 12/24/2022]
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11
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Ping O, Ruixue Y, Jiaqiang D, Kaiyu W, Jing F, Yi G, Xiaoli H, Defang C, Weimin L, Li T, Lizi Y. Subinhibitory Concentrations of Prim-O-Glucosylcimifugin Decrease the Expression of Alpha-Hemolysin in Staphylococcus aureus (USA300). EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2018; 2018:7579808. [PMID: 30105064 PMCID: PMC6076931 DOI: 10.1155/2018/7579808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/09/2018] [Indexed: 11/18/2022]
Abstract
Staphylococcus aureus (S. aureus), an important opportunistic pathogen in human and animal, causes a series of diseases in the impairing of immunity of host and even then death. Alpha-hemolysin (Hla), a primary virulence factor, plays a major role in the pathogenic progress of S. aureus, especially in pneumonia. Prim-O-glucosylcimifugin (POG), a nature chromone compound, is an active ingredient in many Chinese Medicines. In this study, POG investigated the inhibitory effect of the secretion of Hla in S. aureus strain USA300 at the subinhibitory concentrations. The hemolysis assays and western blotting assays showed that POG can decrease the production of Hla in the USA300 growth cell cultures in a dose-dependent manner. The results of RT-PCR revealed that reduction of Hla was related to inhibit the transcription of hla and RNAIII. In the cells experiment, POG was proved to protect A549 cells from Hla-medicated injury. In conclusion, POG was shown the capacity of decreased the production of S. aureus Hla. POG can be developed as a candidate agent to treat S. aureus infections against Hla.
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Affiliation(s)
- Ouyang Ping
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Yang Ruixue
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Deng Jiaqiang
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Wang Kaiyu
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Fang Jing
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Geng Yi
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Huang Xiaoli
- College of Animal Science and Technology, Sichuan Agriculture University, Chengdu, China
| | - Chen Defang
- College of Animal Science and Technology, Sichuan Agriculture University, Chengdu, China
| | - Lai Weimin
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Tang Li
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
| | - Yin Lizi
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, China
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An Ointment Consisting of the Phage Lysin LysGH15 and Apigenin for Decolonization of Methicillin-Resistant Staphylococcus aureus from Skin Wounds. Viruses 2018; 10:v10050244. [PMID: 29734776 PMCID: PMC5977237 DOI: 10.3390/v10050244] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is a common and dangerous pathogen that causes various infectious diseases. Skin damage, such as burn wounds, are at high risk of Staphylococcus aureus colonization and infection, which increases morbidity and mortality. The phage lysin LysGH15 exhibits highly efficient lytic activity against methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. Apigenin (api) significantly decreases haemolysis of rabbit erythrocytes caused by S. aureus and shows anti-inflammatory function. LysGH15 and api were added to Aquaphor to form an LysGH15-api-Aquaphor (LAA) ointment. The LAA ointment simultaneously exhibited bactericidal activity against S. aureus and inhibited haemolysis. In an LAA-treated mouse model of an MRSA-infected skin wound, the mean bacterial colony count decreased to approximately 102 CFU/mg at 18 h after treatment (and the bacteria became undetectable at 96 h), whereas the mean count in untreated mice was approximately 105 CFU/mg of tissue. The LAA ointment also reduced the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IFN-γ) and accelerated wound healing in the mouse model. These data demonstrate the potential efficacy of a combination of LysGH15 and api for use as a topical antimicrobial agent against S. aureus.
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Abstract
Staphylococcus aureus is often involved in severe infections, in which the effects of bacterial virulence factors have great importance. Antistaphylococcal regimens should take into account the different effects of antibacterial agents on the expression of virulence factors and on the host's immune response. A PubMed literature search was performed to select relevant articles on the effects of antibiotics on staphylococcal toxin production and on the host immune response. Information was sorted according to the methods used for data acquisition (bacterial strains, growth models, and antibiotic concentrations) and the assays used for readout generation. The reported mechanisms underlying S. aureus virulence modulation by antibiotics were reviewed. The relevance of in vitro observations is discussed in relation to animal model data and to clinical evidence extracted from case reports and recommendations on the management of toxin-related staphylococcal diseases. Most in vitro data point to a decreased level of virulence expression upon treatment with ribosomally active antibiotics (linezolid and clindamycin), while cell wall-active antibiotics (beta-lactams) mainly increase exotoxin production. In vivo studies confirmed the suppressive effect of clindamycin and linezolid on virulence expression, supporting their utilization as a valuable management strategy to improve patient outcomes in cases of toxin-associated staphylococcal disease.
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Gottschalk S, Ingmer H, Thomsen LE. The lysine-peptoid hybrid LP5 maintain activity under physiological conditions and affects virulence gene expression in Staphylococcus aureus. Peptides 2016; 78:24-9. [PMID: 26851701 DOI: 10.1016/j.peptides.2016.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 01/26/2023]
Abstract
The antimicrobial peptide, LP5, is a lysine-peptoid hybrid, with antimicrobial activity against clinically relevant bacteria. Here, we investigated how various environmental conditions affect the antimicrobial activity of LP5 against Staphylococcus aureus (S. aureus). We found that LP5 maintained activity under host physiological conditions of NaCl, MgCl2 and pH. However, when exposed to serum, LP5 lost activity. Furthermore, when increasing NaCl concentration and lowering pH, the peptide showed reduces activity. When investigating the tolerance mechanisms of S. aureus toward antimicrobial peptides, we found that LP5 was protease resistant. However, the dltA and vraF genes, involved in reducing the net anionic charge of the bacterial cell envelope and sensing of antimicrobial peptides, respectively, played a role in the tolerance of S. aureus against LP5. In addition, the exposure of S. aureus to sub-inhibitory concentrations of LP5 affected the expression of the major virulence factors of S. aureus, revealing a potential as anti-virulence compound. Thus, these results show how environmental factors affect the peptide efficiency and further add to the knowledge on how the peptide affects S. aureus, which is crucial information for designing new peptides for optimizing antimicrobial therapy.
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Affiliation(s)
- Sanne Gottschalk
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.
| | - Line E Thomsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark.
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Savijoki K, Skogman M, Fallarero A, Nyman TA, Sukura A, Vuorela P, Varmanen P. Penicillin G increases the synthesis of a suicidal marker (CidC) and virulence (HlgBC) proteins in Staphylococcus aureus biofilm cells. Int J Med Microbiol 2016; 306:69-74. [PMID: 26725755 DOI: 10.1016/j.ijmm.2015.11.006] [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] [Received: 08/04/2015] [Revised: 10/30/2015] [Accepted: 11/29/2015] [Indexed: 10/22/2022] Open
Abstract
The present study reports the effect of Penicillin G (PenG) on the proteome dynamics of the Staphylococcus aureus strain Newman during biofilm mode of growth. The viability of the 18-h-old biofilm cells challenged with PenG at the concentration of 1mgmL(-1) was first assessed by plate counting, resazurin and LIVE/DEAD fluorescence staining, which indicated that the viability was reduced by ∼35% and ∼90% at 2h and 24h, respectively, after the addition of PenG. Subsequent two-dimensional difference gel electrophoresis (2D DIGE) assay of the treated and non-treated biofilm cells at the indicated time points revealed 45 proteins showing time- and treatment-specific change (1.5-fold, p<0.01). The 2D DIGE results suggested that the PenG-induced decrease in viability was accompanied by an increased synthesis of pyruvate oxidase (CidC), a suicidal marker known to potentiate acetate-dependent cell death in S. aureus. Increased abundance was also found for the TCA cycle associated malate-quinone oxidoreductase (Mqo), the ClpC ATPase, the HlgBC toxin and phage-associated proteins, which suggests that surviving cells have induced these activities as a last effort to overcome lethal doses of PenG. Proteomic results also revealed that the surviving cells were likely to strengthen their peptidoglycan due to the increased abundance of cell-wall biogenesis associated proteins, FemA and Pbp2; a phenomenon associated with dormancy in S. aureus.
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Affiliation(s)
- Kirsi Savijoki
- Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Finland; Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Finland.
| | - Malena Skogman
- Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Finland
| | - Adyary Fallarero
- Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Finland
| | - Tuula A Nyman
- Institute of Biotechnology, University of Helsinki, Finland
| | - Antti Sukura
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Finland
| | - Pia Vuorela
- Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Finland
| | - Pekka Varmanen
- Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Finland
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Gottschalk S, Gottlieb CT, Vestergaard M, Hansen PR, Gram L, Ingmer H, Thomsen LE. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus. J Med Microbiol 2015; 64:1504-1513. [DOI: 10.1099/jmm.0.000177] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Sanne Gottschalk
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
| | - Caroline T. Gottlieb
- National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Martin Vestergaard
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
| | - Paul R. Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Lone Gram
- Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
| | - Line E. Thomsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
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Stapels DAC, Kuipers A, von Köckritz-Blickwede M, Ruyken M, Tromp AT, Horsburgh MJ, de Haas CJC, van Strijp JAG, van Kessel KPM, Rooijakkers SHM. Staphylococcus aureus protects its immune-evasion proteins against degradation by neutrophil serine proteases. Cell Microbiol 2015; 18:536-45. [PMID: 26418545 DOI: 10.1111/cmi.12528] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/20/2015] [Indexed: 12/12/2022]
Abstract
Neutrophils store large quantities of neutrophil serine proteases (NSPs) that contribute, via multiple mechanisms, to antibacterial immune defences. Even though neutrophils are indispensable in fighting Staphylococcus aureus infections, the importance of NSPs in anti-staphylococcal defence is yet unknown. However, the fact that S. aureus produces three highly specific inhibitors for NSPs [the extracellular adherence proteins (EAPs) Eap, EapH1 and EapH2], suggests that these proteases are important for host defences against this bacterium. In this study we demonstrate that NSPs can inactivate secreted virulence factors of S. aureus and that EAP proteins function to prevent this degradation. Specifically, we find that a large group of S. aureus immune-evasion proteins is vulnerable to proteolytic inactivation by NSPs. In most cases, NSP cleavage leads to functional inactivation of virulence proteins. Interestingly, proteins with similar immune-escape functions appeared to have differential cleavage sensitivity towards NSPs. Using targeted mutagenesis and complementation analyses in S. aureus, we demonstrate that all EAP proteins can protect other virulence factors from NSP degradation in complex bacterial supernatants. These findings show that NSPs inactivate S. aureus virulence factors. Moreover, the protection by EAP proteins can explain why this antibacterial function of NSPs was masked in previous studies. Furthermore, our results indicate that therapeutic inactivation of EAP proteins can help to restore the natural host immune defences against S. aureus.
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Affiliation(s)
- D A C Stapels
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - A Kuipers
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M von Köckritz-Blickwede
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - M Ruyken
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - A T Tromp
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M J Horsburgh
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - C J C de Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - J A G van Strijp
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - K P M van Kessel
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - S H M Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
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Combination Therapy of LysGH15 and Apigenin as a New Strategy for Treating Pneumonia Caused by Staphylococcus aureus. Appl Environ Microbiol 2015; 82:87-94. [PMID: 26475103 DOI: 10.1128/aem.02581-15] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 10/10/2015] [Indexed: 01/11/2023] Open
Abstract
Pneumonia is one of the most prevalent Staphylococcus aureus-mediated diseases, and the treatment of this infection is becoming challenging due to the emergence of multidrug-resistant S. aureus, especially methicillin-resistant S. aureus (MRSA) strains. It has been reported that LysGH15, the lysin derived from phage GH15, displays high efficiency and a broad lytic spectrum against MRSA and that apigenin can markedly diminish the alpha-hemolysin of S. aureus. In this study, the combination therapy of LysGH15 and apigenin was evaluated in vitro and in a mouse S. aureus pneumonia model. No mutual adverse influence was detected between LysGH15 and apigenin in vitro. In animal experiments, the combination therapy showed a more effective treatment effect than LysGH15 or apigenin monotherapy (P < 0.05). The bacterial load in the lungs of mice administered the combination therapy was 1.5 log units within 24 h after challenge, whereas the loads in unprotected mice or mice treated with apigenin or LysGH15 alone were 10.2, 4.7, and 2.6 log units, respectively. The combination therapy group showed the best health status, the lowest ratio of wet tissue to dry tissue of the lungs, the smallest amount of total protein and cells in the lung, the fewest pathological manifestations, and the lowest cytokine level compared with the other groups (P < 0.05). With regard to its better protective efficacy, the combination therapy of LysGH15 and apigenin exhibits therapeutic potential for treating pneumonia caused by MRSA. This paper reports the combination therapy of lysin and natural products derived from traditional Chinese medicine.
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Shi C, Zhao X, Li W, Meng R, Liu Z, Liu M, Guo N, Yu L. Inhibitory effect of totarol on exotoxin proteins hemolysin and enterotoxins secreted by Staphylococcus aureus. World J Microbiol Biotechnol 2015; 31:1565-73. [PMID: 26193949 DOI: 10.1007/s11274-015-1905-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/16/2015] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus (S. aureus) causes a wide variety of infections, which are of major concern worldwide. S. aureus produces multiple virulence factors, resulting in food infection and poisoning. These virulence factors include hyaluronidases, proteases, coagulases, lipases, deoxyribonucleases and enterotoxins. Among the extracellular proteins produced by S. aureus that contribute to pathogenicity, the exotoxins α-hemolysin, staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin B (SEB) are thought to be of major significance. Totarol, a plant extract, has been revealed to inhibit the proliferation of several pathogens effectively. However, there are no reports on the effects of totarol on the production of α-hemolysin, SEA or SEB secreted by S. aureus. The aim of this study was to evaluate the effects of totarol on these three exotoxins. Hemolysis assay, western blotting and real-time reverse transcriptase-PCR assay were performed to identify the influence of graded subinhibitory concentrations of totarol on the production of α-hemolysin and the two major enterotoxins, SEA and SEB, by S. aureus in a dose-dependent manner. Moreover, an enzyme linked immunosorbent assay showed that the TNF-α production of RAW264.7 cells stimulated by S. aureus supernatants was inhibited by subinhibitory concentrations of totarol. Form the data, we propose that totarol could potentially be used as a promising natural compound in the food and pharmaceutical industries.
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Affiliation(s)
- Ce Shi
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China
| | - Xingchen Zhao
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China
| | - Wenli Li
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China
| | - Rizeng Meng
- Jilin Entry-Exit Inspection and Quarantine Bureau, Changchun, 130062, People's Republic of China
| | - Zonghui Liu
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China
| | - Mingyuan Liu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Na Guo
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China.
| | - Lu Yu
- Department of Food Quality and Safety, Jilin University, Changchun, 130062, People's Republic of China
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Wang J, Zhou X, Liu S, Li G, Shi L, Dong J, Li W, Deng X, Niu X. Morin hydrate attenuates Staphylococcus aureus virulence by inhibiting the self-assembly of α-hemolysin. J Appl Microbiol 2015; 118:753-63. [PMID: 25564958 DOI: 10.1111/jam.12743] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 12/17/2014] [Accepted: 12/23/2014] [Indexed: 11/26/2022]
Abstract
AIMS To investigate the mechanism by which morin hydrate inhibits the haemolytic activity of α-hemolysin (Hla), a channel-forming toxin that is important for the pathogenesis of disease in experimental animals, and its therapeutic effect against Staphylococcus aureus pneumonia in a mouse model. METHODS AND RESULTS The results from the in vitro (haemolysis, western blot and cytotoxicity assays) and in vivo (mouse model of intranasal lung infection) experiments indicated that morin hydrate, a natural compound with little anti-Staph. aureus activity, could effectively antagonize the cytolytic activity of Hla, alleviate human lung cell injury, and protect against mortality of Staph. aureus pneumonia in a mouse model of infection. Molecular dynamics simulations, free energy calculations and mutagenesis assays were further employed to determine the catalytic mechanism of inhibition, which indicated that a direct binding of morin to the 'Stem' domain of Hla (residues I107 and T109) and the concomitant change in conformation led to the inhibition of the self-assembly of the heptameric transmembrane pore, thus inhibiting the biological activity of Hla for cell lysis. CONCLUSIONS Morin inhibited Staph. aureus virulence via inhibiting the haemolytic activity of α-hemolysin. SIGNIFICANCE AND IMPACT OF THE STUDY These findings suggested that morin is a promising candidate for the development of anti-virulence therapeutic agents for the treatment of Staph. aureus infections.
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Affiliation(s)
- J Wang
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
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Anti-virulence potential of eugenyl acetate against pathogenic bacteria of medical importance. Antonie van Leeuwenhoek 2015; 107:703-10. [DOI: 10.1007/s10482-014-0364-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/18/2014] [Indexed: 01/22/2023]
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Abstract
One of the foremost challenges of drug discovery in any therapeutic area is that of solidifying the correlation between in vitro activity and clinical efficacy. Between these is the confirmation that affecting a particular target in vivo will lead to a therapeutic benefit. In antibacterial drug discovery, there is a key advantage from the start, since the targets are bacteria-therefore, it is simple to ascertain in vitro whether a drug has the desired effect, i.e., bacterial cell inhibition or killing, and to understand the mechanism by which that occurs. The downstream criteria, whether a compound reaches the infection site and achieves appropriately high levels to affect bacterial viability, can be evaluated in animal models of infection. In this way animal models of infection can be a highly valuable and predictive bridge between in vitro drug discovery and early clinical evaluation.The Gram-positive pathogen Staphylococcus aureus causes a wide variety of infections in humans (Archer, Clin Infect Dis 26:1179-1181, 1998) and has been said to be able to infect every tissue type. Fortunately, over the years a great deal of effort has been expended toward developing infection models in rodents using this organism, with good success. This chapter will describe the advantages, methods, and outcome measurements of the rodent models most used in drug discovery for S. aureus. Mouse models will be the focus of this chapter, as they are the most economical and thus most commonly used, but a rat infection model is included as well.
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Tang F, Li WH, Zhou X, Liu YH, Li Z, Tang YS, Kou X, Wang SD, Bao M, Qu LD, Li M, Li B. Puerarin protects against Staphylococcus aureus-induced injury of human alveolar epithelial A549 cells via downregulating alpha-hemolysin secretion. Microb Drug Resist 2013; 20:357-63. [PMID: 24372183 DOI: 10.1089/mdr.2013.0104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Alpha-hemolysin, a secreted pore-forming toxin, plays an indispensable role in the pathogenicity of Staphylococcus aureus. In this study, the antimicrobial activity of puerarin against S. aureus was investigated; as a result, puerarin showed no influence on the growth of this organism. However, hemolysis and western blotting assays showed that puerarin concentration dependently inhibited the secretion of alpha-hemolysin at low concentrations. Real-time RT-PCR assay was further employed to evaluate the transcriptional level of hla, the gene encoding alpha-hemolysin, and RNAIII, an effector molecule of the agr system. The results indicated that the RNAIII expression and subsequent hla transcription were also inhibited by puerarin in a dose-dependent manner. Furthermore, puerarin significantly prevented human alveolar epithelial A549 cells from S. aureus-induced injury. Thereby, puerarin may be considered as a potential candidate for the development of antivirulence drugs in the treatment of S. aureus-mediated infections.
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Affiliation(s)
- Feng Tang
- 1 College of Animal Husbandry and Veterinary, Liaoning Medical University , Jinzhou, China
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Dai XH, Li HE, Lu CJ, Wang JF, Dong J, Wei JY, Zhang Y, Wang X, Tan W, Deng XM, Zhao SH, Zhang MJ. Liquiritigenin prevents Staphylococcus aureus-mediated lung cell injury via inhibiting the production of α-hemolysin. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2013; 15:390-399. [PMID: 23464667 DOI: 10.1080/10286020.2013.771344] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Staphylococcus aureus is a significant Gram-positive bacterium that is associated with a broad spectrum of diseases ranging from minor skin infections to lethal pneumonia, endocarditis, and toxinoses. α-Hemolysin is one of the most important exotoxins that contribute to the pathogenesis of S. aureus infections. Liquiritigenin is one of the most significant active components in licorice. In this study, hemolysis, western blot, and real-time reverse transcription-PCR assays were performed to investigate the impact of liquiritigenin on the production of S. aureus α-hemolysin. The results showed that low concentrations of liquiritigenin remarkably decreased S. aureus α-hemolysin production in a dose-dependent manner. Using live/dead cell staining and lactate dehydrogenase assays, we found that liquiritigenin could protect human lung cells (A549) from α-hemolysin-mediated injury. The data indicated that this compound could potentially be useful in developing drugs aiming at staphylococcal α-hemolysin.
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Affiliation(s)
- Xiao-Han Dai
- College of Veterinary Medicine, Jilin University, Changchun, China.
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Niu X, Qiu J, Wang X, Gao X, Dong J, Wang J, Li H, Zhang Y, Dai X, Lu C, Deng X. Molecular insight into the inhibition mechanism of cyrtominetin to α-hemolysin by molecular dynamics simulation. Eur J Med Chem 2013; 62:320-8. [PMID: 23376250 DOI: 10.1016/j.ejmech.2013.01.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 01/04/2013] [Accepted: 01/08/2013] [Indexed: 11/16/2022]
Abstract
The protein α-hemolysin (α-HL) is a self-assembling exotoxin that binds to the membrane of a susceptible host cell. In this paper, experimental studies show that cyrtominetin (CTM) can inhibit the hemolytic activity of α-HL. To understand how CTM can affect hemolytic activity, molecular dynamics simulations were carried out for α-HL-CTM complex and these results were compared with the crystal structure of monomeric α-HL. With this approach, the analysis revealed that the inhibition of CTM involves CTM directly binding to α-HL. Due to the binding of CTM, the conformation of the critical "Loop" region was restrained. This mechanism was confirmed by the experimental data. These findings indicate that CTM hinders the lysis activity of α-HL through a novel mechanism.
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Affiliation(s)
- Xiaodi Niu
- Department of Food Quality and Safety, Jilin University, Changchun 130062, China
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Dong J, Qiu J, Wang J, Li H, Dai X, Zhang Y, Wang X, Tan W, Niu X, Deng X, Zhao S. Apigenin alleviates the symptoms of Staphylococcus aureus pneumonia by inhibiting the production of alpha-hemolysin. FEMS Microbiol Lett 2012; 338:124-31. [PMID: 23113475 DOI: 10.1111/1574-6968.12040] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022] Open
Abstract
Staphylococcus aureus is a common human pathogenic bacteria that can cause serious infections, including lethal staphylococcal pneumonia. The development of antimicrobial resistance has limited treatment options for this pathogen; consequently, novel antibiotics and strategies are urgently desired to combat these infections. In recent years, virulence factors secreted by pathogenic microorganisms have been developed as targets for drug discovery. Alpha-hemolysin, a pore-forming cytotoxin that is secreted by most S. aureus strains, is essential for the pathogenesis of S. aureus pneumonia. In this study, we report that apigenin, a compound extracted from parsley that has no antimicrobial activity vs. S. aureus in vitro, can remarkably decrease the production of α-hemolysin at low concentrations. When added to the A549 cells and S. aureus co-culture system, apigenin protected A549 cells from α-hemolysin-mediated injury. Furthermore, in vivo tests indicated that apigenin alleviated injury of the lung tissue and decreased cytokine levels in the bronchoalveolar lavage fluid in the mouse model of S. aureus pneumonia.
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Affiliation(s)
- Jing Dong
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China
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Capsaicin protects mice from community-associated methicillin-resistant Staphylococcus aureus pneumonia. PLoS One 2012; 7:e33032. [PMID: 22427935 PMCID: PMC3299732 DOI: 10.1371/journal.pone.0033032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 02/08/2012] [Indexed: 11/20/2022] Open
Abstract
Background α-toxin is one of the major virulence factors secreted by most Staphylococcus aureus strains, which played a central role in the pathogenesis of S. aureus pneumonia. The aim of this study was to investigate the impact of capsaicin on the production of α-toxin by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain USA 300 and to further assess its performance in the treatment of CA-MRSA pneumonia in a mouse model. Methodology/Principal Findings The in vitro effects of capsaicin on α-toxin production by S. aureus USA 300 were determined using hemolysis, western blot, and real-time RT-PCR assays. The influence of capsaicin on the α-toxin-mediated injury of human alveolar epithelial cells was determined using viability and cytotoxicity assays. Mice were infected intranasally with S. aureus USA300; the in vivo protective effects of capsaicin against S. aureus pneumonia were assessed by monitoring the mortality, histopathological changes and cytokine levels. Low concentrations of capsaicin substantially decreased the production of α-toxin by S. aureus USA 300 without affecting the bacterial viability. The addition of capsaicin prevented α-toxin-mediated human alveolar cell (A549) injury in co-culture with S. aureus. Furthermore, the in vivo experiments indicated that capsaicin protected mice from CA-MRSA pneumonia caused by strain USA 300. Conclusions/Significance Capsaicin inhibits the production of α-toxin by CA-MRSA strain USA 300 in vitro and protects mice from CA-MRSA pneumonia in vivo. However, the results need further confirmation with other CA-MRSA lineages. This study supports the views of anti-virulence as a new antibacterial approach for chemotherapy.
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Reduced aeration affects the expression of the NorB efflux pump of Staphylococcus aureus by posttranslational modification of MgrA. J Bacteriol 2012; 194:1823-34. [PMID: 22287526 DOI: 10.1128/jb.06503-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that at acid pH, the transcription of norB, encoding the NorB efflux pump, increases due to a reduction in the phosphorylation level of MgrA, which in turn leads to a reduction in bacterial killing by moxifloxacin, a substrate of the NorB efflux pump. In this study, we demonstrated that reduced oxygen levels did not affect the transcript levels of mgrA but modified the dimerization of the MgrA protein, which remained mostly in its monomeric form. Under reduced aeration, we also observed a 21.7-fold increase in the norB transcript levels after 60 min of growth that contributed to a 4-fold increase in the MICs of moxifloxacin and sparfloxacin for Staphylococcus aureus RN6390. The relative proportions of MgrA in monomeric and dimeric forms were altered by treatment with H(2)O(2), but incubation of purified MgrA with extracts of cells grown under reduced but not normal aeration prevented MgrA from being converted to its dimeric DNA-binding form. This modification was associated with cleavage of a fragment of the dimerization domain of MgrA without change in MgrA phosphorylation and an increase in transcript levels of genes encoding serine proteases in cells incubated at reduced aeration. Taken together, these data suggest that modification of MgrA by proteases underlies the reversal of its repression of norB and increased resistance to NorB substrates in response to reduced-aeration conditions, illustrating a third mechanism of posttranslational modification, in addition to oxidation and phosphorylation, that modulates the regulatory activities of MgrA.
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Li HE, Qiu JZ, Yang ZQ, Dong J, Wang JF, Luo MJ, Pan J, Dai XH, Zhang Y, Song BL, Deng XM. Glycyrrhetinic acid protects mice from Staphylococcus aureus pneumonia. Fitoterapia 2011; 83:241-8. [PMID: 22085765 DOI: 10.1016/j.fitote.2011.10.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/24/2011] [Accepted: 10/31/2011] [Indexed: 11/18/2022]
Abstract
In the present study, the antimicrobial activity of glycyrrhetinic acid (GA) against Staphylococcus aureus, and its influence on the production of S. aureus alpha-haemolysin (Hla) were investigated, along with the in vivo activity of GA against S. aureus-induced pneumonia. GA could not inhibit the growth of S. aureus, but the secretion of Hla by S. aureus was significantly inhibited by low concentrations of GA in a dose-dependent manner. Furthermore, in vivo data show that GA provides protection against staphylococcal pneumonia in a murine model system.
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Affiliation(s)
- Hong-en Li
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun 130062, PR China
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Wang J, Qiu J, Dong J, Li H, Luo M, Dai X, Zhang Y, Leng B, Niu X, Zhao S, Deng X. Chrysin protects mice from Staphylococcus aureus pneumonia. J Appl Microbiol 2011; 111:1551-8. [DOI: 10.1111/j.1365-2672.2011.05170.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Qiu J, Luo M, Wang J, Dong J, Li H, Leng B, Zhang Q, Dai X, Zhang Y, Niu X, Deng X. Isoalantolactone protects against Staphylococcus aureus pneumonia. FEMS Microbiol Lett 2011; 324:147-55. [DOI: 10.1111/j.1574-6968.2011.02397.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/23/2011] [Accepted: 08/24/2011] [Indexed: 12/16/2022] Open
Affiliation(s)
- Jiazhang Qiu
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Mingjing Luo
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Jianfeng Wang
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Jing Dong
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Hongen Li
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Bingfeng Leng
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Qian Zhang
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Xiaohan Dai
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Yu Zhang
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
| | - Xiaodi Niu
- College of Quartermaster Technology; Jilin University; Changchun; China
| | - Xuming Deng
- Key Laboratory of Zoonosis; Ministry of Education; Institute of Zoonosis; College of Animal Science and Veterinary Medicine; Jilin University; Changchun; China
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32
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Goss CH, Muhlebach MS. Review: Staphylococcus aureus and MRSA in cystic fibrosis. J Cyst Fibros 2011; 10:298-306. [PMID: 21719362 DOI: 10.1016/j.jcf.2011.06.002] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 05/27/2011] [Accepted: 06/03/2011] [Indexed: 01/31/2023]
Abstract
BACKGROUND Staphylococcus aureus (S. aureus) is one of the earliest bacteria detected in infants and children with cystic fibrosis (CF). The rise of methicillin resistant S. aureus (MRSA) in the last 10 years has caused a lot of attention to this organism. RESULTS The aim of this review is to provide a general overview of methicillin sensitive S. aureus (MSSA) and MRSA, discuss special aspects of S. aureus in cystic fibrosis, and to review treatment concepts. Microbiology of the organism will be reviewed along with data regarding the epidemiology of both MSSA and MRSA. Antibiotic treatments both in regards to acute management and eradication of MSSA and MRSA will be reviewed. Prophylaxis of MSSA in CF remains controversial. Treatment with anti-staphylococcal agents reduces the infection rate with MSSA but may lead to a higher rate of infection with P. aeruginosa. In regards to MRSA, there is a paucity of clinical data regarding approaches to eradication. CONCLUSIONS To advance the care of CF patients, controlled clinical trials are urgently needed to find the optimal approach to treating CF patients who are infected with either MSSA or MRSA.
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Qiu J, Jiang Y, Xia L, Xiang H, Feng H, Pu S, Huang N, Yu L, Deng X. Subinhibitory concentrations of licochalcone A decrease alpha-toxin production in both methicillin-sensitive and methicillin-resistantStaphylococcus aureusisolates. Lett Appl Microbiol 2010; 50:223-9. [DOI: 10.1111/j.1472-765x.2009.02783.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Henderson LC, Li J, Nation RL, Velkov T, Pfeffer FM. Developing an anion host for lipid A binding and antibacterial activity. Chem Commun (Camb) 2010; 46:3197-9. [DOI: 10.1039/b925135a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Phillips JR, Tripp TJ, Regelmann WE, Schlievert PM, Wangensteen OD. Staphylococcal alpha-toxin causes increased tracheal epithelial permeability. Pediatr Pulmonol 2006; 41:1146-52. [PMID: 16998922 DOI: 10.1002/ppul.20501] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Staphylococcus aureus is an important cause of pulmonary infections. The role of S. aureus alpha-toxin as a virulence factor is unclear. We hypothesized that airway epithelium is a target of S. aureus alpha-toxin and that exposure of airway epithelium to alpha-toxin results in damage to the airway epithelium. To examine the hypothesis that alpha-toxin is capable of independently producing airway epithelium damage as measured by permeability and morphometry, an isolated whole mouse trachea test apparatus was developed. In vitro epithelial permeability (P) was calculated and digital micrographs were analyzed morphometrically. Purified S. aureus alpha-toxin produced a significant increase in tracheal epithelial P (P < 0.05). Morphometric analysis revealed the ratio of adherent tracheal epithelium attached to the basement membrane divided by the total length of the basement membrane decreased in a dose-dependent manner with 1 microg/ml alpha-toxin and 10 microg/ml alpha-toxin (P < 0.05). We developed a novel isolated whole mouse trachea test apparatus for the measurement of tracheal epithelium damage. Increased P and separation of the tracheal epithelium from the basement membrane occurred after S. aureus alpha-toxin exposure. We conclude that mammalian airway epithelium is a target of S. aureus alpha-toxin.
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Affiliation(s)
- James R Phillips
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Fernandez J. In vivo animal models: quantitative models used for identifying antibacterial agents. CURRENT PROTOCOLS IN PHARMACOLOGY 2006; Chapter 13:Unit13A.5. [PMID: 22294173 DOI: 10.1002/0471141755.ph13a05s34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Determining the in vivo bactericidal potential of novel agents is critical for selecting drug candidates. Described in this unit are two protocols that measure the amount of bacterial killing under very different conditions. The mouse pouch protocol is a rapid assay that provides efficacy data in an acute infection, whereas the rabbit tissue cage protocol assesses the ability of a compound to eradicate bacteria in a chronic abscess infection. Data from these tests, along with those from other qualitative and quantitative assays, are important for defining antibacterial efficacy in vivo.
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Affiliation(s)
- Jeffrey Fernandez
- Johnson & Johnson Pharmaceutical Research and Development, L.L.C., Raritan, New Jersey, USA
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Paul K, Rietschel E, Ballmann M, Griese M, Worlitzsch D, Shute J, Chen C, Schink T, Döring G, van Koningsbruggen S, Wahn U, Ratjen F. Effect of Treatment with Dornase Alpha on Airway Inflammation in Patients with Cystic Fibrosis. Am J Respir Crit Care Med 2004; 169:719-25. [PMID: 14684561 DOI: 10.1164/rccm.200307-959oc] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Recombinant human deoxyribonuclease (rhDNase) has been shown to improve lung function and reduce the number of pulmonary exacerbations in patients with cystic fibrosis (CF), but its long-term effect on airway inflammation remains unknown. In this study, we used bronchoalveolar lavage (BAL) to investigate the long-term effect of rhDNase on inflammation in patients with CF having mild lung disease. A total of 105 patients with CF (> or =5 years of age) having normal lung function were randomized to receive rhDNase (2.5 mg/day) or no rhDNase. Patients with a normal percentage of neutrophils in BAL fluid at baseline were not randomized and served as the control group. The percentage of neutrophils in the pooled BAL sample was similar in both randomized groups at baseline. A significant increase in neutrophils was observed over the 3-year study period in both untreated patients and control subjects, whereas neutrophils remained unchanged in patients treated with rhDNase. Elastase activities and interleukin-8 concentrations also increased in untreated patients and remained stable in patients on rhDNase. We conclude that in patients with CF, an increase in neutrophilic airway inflammation is found that is positively influenced by rhDNase treatment.
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Affiliation(s)
- Karl Paul
- Department of Pediatric Pneumology and Immunology, Charité, Germany
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Bronner S, Jehl F, Peter JD, Ploy MC, Renault C, Arvis P, Monteil H, Prevost G. Moxifloxacin efficacy and vitreous penetration in a rabbit model of Staphylococcus aureus endophthalmitis and effect on gene expression of leucotoxins and virulence regulator factors. Antimicrob Agents Chemother 2003; 47:1621-9. [PMID: 12709331 PMCID: PMC153310 DOI: 10.1128/aac.47.5.1621-1629.2003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial endophthalmitis is a serious complication of ocular surgery and of eye trauma; the leading causative organisms are Staphylococcus aureus strains. Tissue damage is due both to the host inflammatory response and to toxin synthesis by bacteria. Systemic treatment remains difficult because most antibiotics show poor ocular penetration. Moxifloxacin (MXF), a novel fluoroquinolone, was evaluated for its penetration into the vitreous of normal rabbit eyes and of eyes of rabbits infected for 24 h with methicillin-susceptible and methicillin-resistant S. aureus (MSSA and MRSA) following a single intravenous administration of 5 or 20 mg/kg. MXF penetration was rapid and efficient regardless of the dose, ranging from 28 to 52%. An inflammatory state of the vitreous significantly increased penetration after the 20-mg/kg dose, with penetration reaching 52%. Concentrations determined in the vitreous cavity following a 20-mg/kg administration showed a 3.5-fold decrease of the bacterial density within 5 h for MSSA (MIC, 0.125 micro g/ml) and a 1.6-fold decrease for MRSA (MIC, 4 micro g/ml) strains, respectively. By using a semiquantitative reverse transcription-PCR method, the expression of luk-PV and hlgCB, but not hlgA, encoding staphylococcal leukotoxins, was detected in the vitreous without MXF treatment. A slight decrease in the expression of leucotoxins and sarA, agr, and sigB virulence regulatory factors was observed 1 h following the administration of 5 mg of MXF per kg.
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Affiliation(s)
- Stéphane Bronner
- Institut de Bactériologie, Faculté de Médecine, Université Louis Pasteur-Hôpitaux Universitaires de Strasbourg, F-67000 Strasbourg, France
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