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Alreshidi MM, Dunstan RH, Macdonald MM, Smith ND, Gottfries J, Roberts TK. Amino acids and proteomic acclimation of Staphylococcus aureus when incubated in a defined minimal medium supplemented with 5% sodium chloride. Microbiologyopen 2019; 8:e00772. [PMID: 30739392 PMCID: PMC6562129 DOI: 10.1002/mbo3.772] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 11/06/2022] Open
Abstract
Staphylococcus aureus is a versatile bacterium that can adapt to survive and grow in a wide range of salt concentrations. This study investigated whether the cells could mount a response to survive a challenge of 5% NaCl in a minimal incubation medium that would not support cell replication. Cells were grown in liquid culture, washed and then incubated for 90 min at 37°C in a medium that contained only glycine and glucose as substrates in PBS plus trace elements. The control cells were compared with a treatment group which was incubated with an additional 5% NaCl. Significantly more glycine was taken up by the cells exposed to 5% NaCl compared with control cells, and both groups consumed 99% of the glucose supplied. The NaCl treated cells had significantly higher cytoplasmic levels of proline and glutamic acid as well as lower levels of alanine and methionine compared with the controls (p < 0.05). The levels of the two major cytoplasmic amino acids, aspartic acid and glycine, remained constant in control and treated cells. Proteomic analyses revealed that 10 proteins showed differential responses between the control and treatment groups. The reductions in proteins were primarily associated with processes of protein biosynthesis, pathogenicity, and cell adhesion. Since cell numbers remained constant during the incubation period in minimal medium, it was concluded that there was no cell division to support population growth. The results provided evidence that the cells in the minimal medium exposed to the NaCl treatment underwent in situ homeostatic changes to adjust to the new environmental conditions. It was proposed that this represented a phenotypic shift to form cells akin to small colony variants, with lower metabolic rates and lower levels of key proteins associated with pathogenicity.
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Affiliation(s)
- Mousa M Alreshidi
- Department of Biology, College of Science, University of Hail, Hail, Saudi Arabia
| | - R Hugh Dunstan
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, Callaghan, New South Wales, Australia
| | - Margaret M Macdonald
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, Callaghan, New South Wales, Australia
| | - Nathan D Smith
- Analytical and Biomolecular Research Facility (ABRF), University of Newcastle, Callaghan, New South Wales, Australia
| | - Johan Gottfries
- Department of Chemistry, Gothenburg University, Gothenburg, Sweden
| | - Tim K Roberts
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, Callaghan, New South Wales, Australia
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103
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Bai JR, Wu YP, Elena G, Zhong K, Gao H. Insight into the effect of quinic acid on biofilm formed byStaphylococcus aureus. RSC Adv 2019; 9:3938-3945. [PMID: 35518066 PMCID: PMC9060517 DOI: 10.1039/c8ra09136f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/22/2019] [Indexed: 01/08/2023] Open
Abstract
The biofilm formation of Staphylococcus aureus on food contact surfaces is the main risk of food contamination. In the present study, we firstly investigated the inhibitory effect of quinic acid (QA) on biofilm formed by S. aureus. Crystal violet staining assay and microscopy analysis clearly showed that QA at sub-MIC concentrations was able to significantly reduce the biofilm biomass and cause a collapse on biofilm architecture. Meanwhile, fibrinogen binding assay showed that QA had obviously effect on the S. aureus bacteria adhesion. XTT reduction assay and confocal laser scanning microscopic images revealed that QA significantly decreased metabolic activity and viability of biofilm cells. In addition, qRT-PCR analysis explored the potential inhibitory mechanism of QA against biofilm formation, which indicated that QA significantly repressed the gene sarA and activated the gene agrA. Moreover, QA exhibited a highly ability to reduce the number of sessile S. aureus cells adhered on the stainless steel. So, it was suggested that QA could be used as a promising antibiofilm agent to control biofilm formation of S. aureus. QA effectively inhibited S. aureus biofilm formation. The key genes of biofilm inhibition induced by QA were agrA and sarA.![]()
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Affiliation(s)
- Jin-Rong Bai
- College of Light Industry
- Textile and Food Engineering and Healthy Food Evaluation Research Center
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Yan-Ping Wu
- College of Light Industry
- Textile and Food Engineering and Healthy Food Evaluation Research Center
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Grosu Elena
- College of Light Industry
- Textile and Food Engineering and Healthy Food Evaluation Research Center
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Kai Zhong
- College of Light Industry
- Textile and Food Engineering and Healthy Food Evaluation Research Center
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Hong Gao
- College of Light Industry
- Textile and Food Engineering and Healthy Food Evaluation Research Center
- Sichuan University
- Chengdu 610065
- P. R. China
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104
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Biofilm Formation by Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains from Hospitalized Patients in Poland. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4657396. [PMID: 30687745 PMCID: PMC6327255 DOI: 10.1155/2018/4657396] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 11/20/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
Biofilm-mediated infections in the hospital environment have a significant negative impact on patient health. This study aimed to investigate biofilm production in vitro and the presence of icaABCD genes in methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains isolated from hospitalized patients. MRSA (73) and MSSA (57) strains were evaluated for biofilm production by the microtiter plate method. The presence of ica operon was investigated by PCR. Out of 130 strains, 99.2% were biofilm producers. Strong biofilms were formed by 39.7% of MRSA and 36.8% of MSSA strains. The highest percentage of strong biofilm producers was found among the strains isolated from sputum and tracheostomy tube (66.7%), nose and catheter (50%), throat (44.4%), and bronchoalveolar washings (43.8%). The strains isolated from bronchoalveolar washings produced significantly more biofilm than strains isolated from wound and anus. The ability of biofilm forming by fecal strains was significantly lower compared to strains from other materials. MRSA strains had significantly higher ability of biofilm formation than MSSA strains (P = 0.000247). The presence of ica operon in MRSA was detected in all strains. Comparison of strong biofilm biomass of the strains with icaABCD, icaABD, and icaAD revealed that strains with icaABCD and icaABD produced highly significantly more biofilm than strains with icaAD. Biofilm forming by both MRSA and MSSA strains indicates high ability of theses strains to persist in hospital environment which increases the risk of disease development in hospitalized patients.
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105
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Manandhar S, Singh A, Varma A, Pandey S, Shrivastava N. Biofilm Producing Clinical Staphylococcus aureus Isolates Augmented Prevalence of Antibiotic Resistant Cases in Tertiary Care Hospitals of Nepal. Front Microbiol 2018; 9:2749. [PMID: 30538678 PMCID: PMC6277500 DOI: 10.3389/fmicb.2018.02749] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/26/2018] [Indexed: 11/21/2022] Open
Abstract
Staphylococcus aureus, a notorious human pathogen, is a major cause of the community as well as healthcare associated infections. It can cause a diversity of recalcitrant infections mainly due to the acquisition of resistance to multiple drugs, its diverse range of virulence factors, and the ability to produce biofilm in indwelling medical devices. Such biofilm associated chronic infections often lead to increase in morbidity and mortality posing a high socio-economic burden, especially in developing countries. Since biofilm formation and antibiotic resistance function dependent on each other, detection of biofilm expression in clinical isolates would be advantageous in treatment decision. In this premise, we attempt to investigate the biofilm formation and its association with antibiotic resistance in clinical isolates from the patients visiting tertiary health care hospitals in Nepal. Bacterial cells isolated from clinical samples identified as S. aureus were examined for in-vitro biofilm production using both phenotypic and genotypic assays. The S. aureus isolates were also examined for susceptibility patterns of clinically relevant antibiotics as well as inducible clindamycin resistance using standard microbiological techniques and D-test, respectively. Among 161 S. aureus isolates, 131 (81.4%) were methicillin resistant S. aureus (MRSA) and 30 (18.6%) were methicillin sensitive S. aureus (MSSA) strains. Although a majority of MRSA strains (69.6%) showed inducible clindamycin resistance, almost all isolates (97% and 94%) were sensitive toward chloramphenicol and tetracycline, respectively. Detection of in vitro production of biofilm revealed the association of biofilm with methicillin as well as inducible clindamycin resistance among the clinical S. aureus isolates.
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Affiliation(s)
- Sarita Manandhar
- Tri-Chandra Multiple College, Tribhuvan University, Kathmandu, Nepal.,Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Anjana Singh
- Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Shanti Pandey
- The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Neeraj Shrivastava
- Amity Institute of Microbial Technology, Amity University, Noida, India.,Institute of Biotechnology, Zhejiang University, Hangzhou, China
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106
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Rodrigues S, Paillard C, Van Dillen S, Tahrioui A, Berjeaud JM, Dufour A, Bazire A. Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study. Pathogens 2018; 7:pathogens7040092. [PMID: 30486310 PMCID: PMC6313714 DOI: 10.3390/pathogens7040092] [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: 09/28/2018] [Revised: 11/20/2018] [Accepted: 11/23/2018] [Indexed: 02/05/2023] Open
Abstract
Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A flow cell system was employed to grow biofilms to obtain both structural and transcriptomic views of the biofilms. We found that 3615 genes were differentially expressed, confirming that biofilm and planktonic lifestyles are very different. As expected, the differentially expressed genes included those involved in biofilm formation, such as motility- and polysaccharide synthesis-related genes. The data show that quorum sensing is probably mediated by the AI-2/LuxO system in V. tapetis biofilms. The expression of genes encoding the Type VI Secretion System and associated exported proteins are strongly induced, suggesting that V. tapetis activates this virulence factor when living in biofilm.
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Affiliation(s)
- Sophie Rodrigues
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Christine Paillard
- UMR6539, Laboratoire des Sciences de l'Environnement Marin (LEMAR), Centre National de la Recherche Scientifique, Institut Universitaire Européen de la Mer, Université de Brest, UBO, IRD, Ifremer, 29280 Plouzané, France.
| | - Sabine Van Dillen
- DuPont Nutrition and Health, Danisco France SAS, BP10, F-86220 Dangé-Saint-Romain, France.
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University Rouen-Normandy, 27000 Evreux, France.
| | - Jean-Marc Berjeaud
- UMR 7267, Laboratoire d'Ecologie et Biologie des interactions (EBI), Université de Poitiers, 86000 Poitiers, France.
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
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107
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Panda S, Singh DV. Biofilm Formation by ica-Negative Ocular Isolates of Staphylococcus haemolyticus. Front Microbiol 2018; 9:2687. [PMID: 30487781 PMCID: PMC6247817 DOI: 10.3389/fmicb.2018.02687] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/22/2018] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus haemolyticus is the second most frequently isolated CoNS from ocular infections and human blood cultures. In this study, we examined 18 ocular S. haemolyticus isolates for their capacity to form biofilm and conducted detachment assay to determine the composition of the biofilm matrix and involvement of various elements in cell lysis. PCR identified the presence of biofilm-associated genes, and ica operon and CLSM visualized the components of the biofilm matrix. We found that PIA-independent biofilm formation is the characteristic feature of S. haemolyticus isolates, irrespective of the sources of isolation, and protein or DNA or both are the major components of the biofilm matrix. Cell lysis enabling DNA release was an essential step for biofilm attachment during the initial stages of biofilm development. The srtA transcript expression study indicates its role in the early stages of biofilm development. We found the presence of antibiotic resistance genes in the eDNA and gDNA thus suggesting the possible role of biofilm in horizontal gene transfer of antibiotic resistance determinants. The overall study indicates that S. haemolyticus formed the biofilm comprising of protein or DNA or both and srtA play a role in the initial development of biofilm.
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Affiliation(s)
- Sasmita Panda
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Durg Vijai Singh
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
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108
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Kot B, Sytykiewicz H, Sprawka I. Expression of the Biofilm-Associated Genes in Methicillin-Resistant Staphylococcus aureus in Biofilm and Planktonic Conditions. Int J Mol Sci 2018; 19:ijms19113487. [PMID: 30404183 PMCID: PMC6274806 DOI: 10.3390/ijms19113487] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 10/30/2018] [Accepted: 11/02/2018] [Indexed: 11/16/2022] Open
Abstract
The role of genes that are essential for development of Staphylococcus aureus biofilm during infection is not fully known. mRNA from two methicillin-resistant S. aureus strains that formed weak and strong biofilm on polystyrene plates were isolated at five time points from cells grown in biofilm and planktonic culture. Quantitative real-time PCR analysis showed that the expression levels of investigated genes under biofilm conditions were significantly higher than under planktonic conditions. The expression levels of the gene encoding elastin binding protein (ebps) and laminin binding protein (eno) were significantly increased in biofilm at 3 h, both in strongly and weakly adhering strain. The peak expression of fib gene encoding fibrinogen binding protein was found at 6 and 8 h in the case of strongly and weakly adhering strain, respectively. The expression of icaA and icaD genes in both strains was significantly higher under biofilm conditions when comparing to planktonic cells during 12 h. The expression level of the genes encoding binding proteins and the glucosamine polymer polysaccharide intercellular adhesin (PIA) slowly decreased after 24 h. Finally, we found that the expression levels of genes encoding binding factors in weakly adhering strain were significantly lower than in strongly adhering strain.
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Affiliation(s)
- Barbara Kot
- Department of Microbiology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
| | - Hubert Sytykiewicz
- Department of Biochemistry and Molecular Biology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
| | - Iwona Sprawka
- Department of Biochemistry and Molecular Biology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
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109
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Development and Evaluation of an Injectable Chitosan/β-Glycerophosphate Paste as a Local Antibiotic Delivery System for Trauma Care. J Funct Biomater 2018; 9:jfb9040056. [PMID: 30322006 PMCID: PMC6306749 DOI: 10.3390/jfb9040056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/23/2018] [Accepted: 10/09/2018] [Indexed: 01/03/2023] Open
Abstract
Complex open musculoskeletal wounds are a leading cause of morbidity worldwide, partially due to a high risk of bacterial contamination. Local delivery systems may be used as adjunctive therapies to prevent infection, but they may be nondegradable, possess inadequate wound coverage, or migrate from the wound site. To address this issue, a thermo-responsive, injectable chitosan paste was fabricated by incorporating beta-glycerophosphate. The efficacy of thermo-paste as an adjunctive infection prevention tool was evaluated in terms of cytocompatibility, degradation, antibacterial, injectability, and inflammation properties. In vitro studies demonstrated thermo-paste may be loaded with amikacin and vancomycin and release inhibitory levels for at least 3 days. Further, approximately 60% of thermo-paste was enzymatically degraded within 7 days in vitro. The viability of cells exposed to thermo-paste exceeded ISO 10993-5 standards with approximately 73% relative viability of a control chitosan sponge. The ejection force of thermo-paste, approximately 20 N, was lower than previously studied paste formulations and within relevant clinical ejection force ranges. An in vivo murine biocompatibility study demonstrated that thermo-paste induced minimal inflammation after implantation for 7 days, similar to previously developed chitosan pastes. Results from these preliminary preclinical studies indicate that thermo-paste shows promise for further development as an antibiotic delivery system for infection prevention.
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110
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Staphylococcus aureus Biofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection. mSphere 2018; 3:3/4/e00341-18. [PMID: 30111629 PMCID: PMC6094059 DOI: 10.1128/msphere.00341-18] [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] [Indexed: 01/11/2023] Open
Abstract
The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections. Staphylococcus aureus is a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed that Pseudomonas aeruginosa exhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate if S. aureus biofilm growth in the CF airways is impacted by virus coinfection, we evaluated S. aureus growth on CF AECs. Initial studies showed an increase in S. aureus growth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed with S. aureus CF clinical isolates. Apical conditioned medium from RSV-infected cells promoted S. aureus biofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefits S. aureus biofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterized S. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions of S. aureus and RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation of S. aureus genes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection. IMPORTANCE The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.
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111
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Gunvig A, Andresen MS, Jacobsen T, Borggaard C. Staphtox predictor - A dynamic mathematical model to predict formation of Staphylococcus enterotoxin during heating and fermentation of meat products. Int J Food Microbiol 2018; 285:81-91. [PMID: 30071496 DOI: 10.1016/j.ijfoodmicro.2018.07.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 06/14/2018] [Accepted: 07/22/2018] [Indexed: 11/26/2022]
Abstract
Existing growth models for S. aureus predict growth in relation to temperature, aw/NaCl and pH, and the assessment of probable Staphylococcus enterotoxin (SE) formation is based solely on the number of S. aureus. However, during the production of meat products such as fermented sausages and semi-processed hams, growth of S. aureus is a critical control point in HACCP plans. There is a need to develop a model that evaluates the safety of the product regarding SE formation in relation to the product composition, changes in pH or temperature during the processing and the number of S. aureus in the final product. The objective of the present work is to develop a mathematical model that predicts both the increase in the number of S. aureus and whether SE formation is possible in different meat product processes. A total of 78 experiments were carried out in a meat model system. The experiments covered a range of different temperatures (10-40 °C), pH (4.6-6.0), water phase salt (WPS) (2.2-5.6%) and Sodium nitrite concentrations (0-150 ppm). The meat model system was inoculated with approximately 103 CFU/g of a multi-strain cocktail and incubated at the different temperatures. The cocktail consisted of three strains of S. aureus producing the Staphylococcus enterotoxins A to D (SEA to SED) and a methicillin-resistant strain producing SEG, SEI, SEM, SEN, SEO and SEU. Enumeration of S. aureus was performed several times during the incubation, SE was extracted from samples with >5 log CFU/g, and the SEA-E content was analysed by an ELISA method. Maximum growth rates and lag times calculated from microbiological data, together with temperature, pH, WPS and Sodium nitrite, were used to develop a SE and a growth model. The growth model was developed by training a neural network and the SE model based on logistic regression. The SE and growth models were validated on separate data sets (N = 200 SE model, N = 63 growth model) including both dynamic and static conditions. The SE model predicted all occurrences of toxin formation in the validation data sets. The growth model is a fail-safe model and the prediction errors are comparable to laboratory reproducibility. In conclusion, the models are applicable for predicting the increase in S. aureus and for evaluating if SE formation is likely during processing of meat products. The models are available to producers and other interested parties at www.dmripredict.dk.
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Affiliation(s)
- A Gunvig
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark.
| | - M S Andresen
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
| | - T Jacobsen
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
| | - C Borggaard
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
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112
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Tarsia C, Danielli A, Florini F, Cinelli P, Ciurli S, Zambelli B. Targeting Helicobacter pylori urease activity and maturation: In-cell high-throughput approach for drug discovery. Biochim Biophys Acta Gen Subj 2018; 1862:2245-2253. [PMID: 30048738 DOI: 10.1016/j.bbagen.2018.07.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/12/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Helicobacter pylori is a bacterium strongly associated with gastric cancer. It thrives in the acidic environment of the gastric niche of large portions of the human population using a unique adaptive mechanism that involves the catalytic activity of the nickel-dependent enzyme urease. Targeting urease represents a key strategy for drug design and H. pylori eradication. METHOD Here, we describe a novel method to screen, directly in the cellular environment, urease inhibitors. A ureolytic Escherichia coli strain was engineered by cloning the entire urease operon in an expression plasmid and used to test in-cell urease inhibition with a high-throughput colorimetric assay. A two-plasmid system was further developed to evaluate the ability of small peptides to block the protein interactions that lead to urease maturation. RESULTS The developed assay is a robust cellular model to test, directly in the cell environment, urease inhibitors. The efficacy of a co-expressed peptide to affect the interaction between UreF and UreD, two accessory proteins necessary for urease activation, was observed. This event involves a process that occurs through folding upon binding, pointing to the importance of intrinsically disordered hot spots in protein interfaces. CONCLUSIONS The developed system allows the concomitant screening of a large number of drug candidates that interfere with the urease activity both at the level of the enzyme catalysis and maturation. GENERAL SIGNIFICANCE As inhibition of urease has the potential of being a global antibacterial strategy for a large number of infections, this work paves the way for the development of new candidates for antibacterial drugs.
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Affiliation(s)
- Cinzia Tarsia
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Alberto Danielli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Francesca Florini
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Paolo Cinelli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Stefano Ciurli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Barbara Zambelli
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy.
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113
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Kim CY, Lee M, Lee K, Yoon SS, Lee I. Network-based genetic investigation of virulence-associated phenotypes in methicillin-resistant Staphylococcus aureus. Sci Rep 2018; 8:10796. [PMID: 30018396 PMCID: PMC6050336 DOI: 10.1038/s41598-018-29120-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 07/02/2018] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus is a gram-positive bacterium that causes a wide range of infections. Recently, the spread of methicillin-resistant S. aureus (MRSA) strains has seriously reduced antibiotic treatment options. Anti-virulence strategies, the objective of which is to target the virulence instead of the viability of the pathogen, have become widely accepted as a means of avoiding the emergence of new antibiotic-resistant strains. To increase the number of anti-virulence therapeutic options, it is necessary to identify as many novel virulence-associated genes as possible in MRSA. Co-functional networks have proved useful for mapping gene-to-phenotype associations in various organisms. Herein, we present StaphNet (www.inetbio.org/staphnet), a genome-scale co-functional network for an MRSA strain, S. aureus subsp. USA300_FPR3757. StaphNet, which was constructed by the integration of seven distinct types of genomics data within a Bayesian statistics framework, covers approximately 94% of the coding genome with a high degree of accuracy. We implemented a companion web server for network-based gene prioritization of the phenotypes of 31 different S. aureus strains. We demonstrated that StaphNet can effectively identify genes for virulence-associated phenotypes in MRSA. These results suggest that StaphNet can facilitate target discovery for the development of anti-virulence drugs to treat MRSA infection.
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Affiliation(s)
- Chan Yeong Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Muyoung Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Keehoon Lee
- Department of Microbiology and Immunology, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Sang Sun Yoon
- Department of Microbiology and Immunology, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Korea.
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Lim SY, Teh CSJ, Thong KL. Biofilm-Related Diseases and Omics: Global Transcriptional Profiling of Enterococcus faecium Reveals Different Gene Expression Patterns in the Biofilm and Planktonic Cells. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2018; 21:592-602. [PMID: 29049010 DOI: 10.1089/omi.2017.0119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Enterococcus faecium is an opportunistic pathogen with a remarkable ability to acquire resistance toward multiple antibiotics, including those of last-resort drugs such as vancomycin and daptomycin. The occurrence of vancomycin-resistant E. faecium is on the rise and there is a need to understand the virulence of this organism. One of the factors that contributes to the virulence is the ability to form biofilms. Since bacteria in biofilm state are more resistant to antibiotics and host immune response, understanding the molecular mechanism of biofilm development is important to control biofilm-related diseases. The aim of this study was to determine the global gene expression profiles of an E. faecium strain, VREr5, during the early event of sessile growth compared with its planktonic phase through RNA-sequencing approach. The results clearly illustrated distinct expression profiles of the planktonic and biofilm cells. A total of 177 genes were overexpressed in the biofilm cells. Most of them encode for proteins involved in adherence, such as the ebpABCfm locus. Genes associated with plasmid replication, gene exchange, and protein synthesis were also upregulated during the early event of biofilm development. Furthermore, the transcriptome analysis also identified genes such as fsrB, luxS, and spx that might suppress biofilm formation in VREr5. The putative biofilm-related bee locus was found to be downregulated. These new findings could provide caveats for future studies on the regulation and maintenance of biofilm and development of biomarkers for biofilm-related diseases.
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Affiliation(s)
- Shu Yong Lim
- 1 Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur, Malaysia
| | - Cindy Shuan Ju Teh
- 2 Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- 1 Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur, Malaysia
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115
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Influence of subinhibitory concentrations of NH125 on biofilm formation & virulence factors of Staphylococcus aureus. Future Med Chem 2018; 10:1319-1331. [PMID: 29846088 DOI: 10.4155/fmc-2017-0286] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
AIM l-benzyl-3-cetyl-2-methylimidazolium iodide (NH125) can inhibit Staphylococcus aureus growth. We investigated the effects of sub-MIC concentrations of NH125 on S. aureus biofilm and virulence. Methodology & results: Three strains of S. aureus were tested. Sub-lethal concentrations of NH125 repressed biofilm formation. At partial sub-MICs, NH125 downregulated the expression of most virulence, while strain-dependent effects were found in the production of α-hemolysin, δ-hemolysin, coagulase and nuclease. In Galleria mellonella model, methicillin-resistant S. aureus pre-exposed to NH125 demonstrated significantly lower killing (p = 0.032 for 1/16 and 1/8 MICs; 0.008 for 1/4 MIC; and 0.001 for 1/2 MIC). CONCLUSION Sub-MIC concentrations of NH125 inhibited biofilm formation and virulence of S. aureus. These findings provide further support for evaluating the clinical efficacy of NH125 in staphylococcal infection.
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116
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Endoribonuclease YbeY Is Linked to Proper Cellular Morphology and Virulence in Brucella abortus. J Bacteriol 2018; 200:JB.00105-18. [PMID: 29632093 DOI: 10.1128/jb.00105-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/03/2018] [Indexed: 12/14/2022] Open
Abstract
The YbeY endoribonuclease is one of the best-conserved proteins across the kingdoms of life. In the present study, we demonstrated that YbeY in Brucella abortus is linked to a variety of important activities, including proper cellular morphology, mRNA transcript levels, and virulence. Deletion of ybeY in B. abortus led to a small-colony phenotype when the bacteria were grown on agar medium, as well as to significant aberrations in the morphology of the bacterial cell as evidenced by electron microscopy. Additionally, compared to the parental strain, the ΔybeY strain was significantly attenuated in both macrophage and mouse models of infection. The ΔybeY strain also showed increased sensitivities to several in vitro-applied stressors, including bile acid, hydrogen peroxide, SDS, and paraquat. Transcriptomic analysis revealed that a multitude of mRNA transcripts are dysregulated in the ΔybeY strain, and many of the identified mRNAs encode proteins involved in metabolism, nutrient transport, transcriptional regulation, and flagellum synthesis. We subsequently constructed gene deletion strains of the most highly dysregulated systems, and several of the YbeY-linked gene deletion strains exhibited defects in the ability of the bacteria to survive and replicate in primary murine macrophages. Taken together, these data establish a clear role for YbeY in the biology and virulence of Brucella; moreover, this work further illuminates the highly varied roles of this widely conserved endoribonuclease in bacteria.IMPORTANCEBrucella spp. are highly efficient bacterial pathogens of animals and humans, causing significant morbidity and economic loss worldwide, and relapse of disease often occurs following antibiotic treatment of human brucellosis. As such, novel therapeutic strategies to combat Brucella infections are needed. Ribonucleases in the brucellae are understudied, and these enzymes represent elements that may be potential targets for future treatment approaches. The present work demonstrates the importance of the YbeY endoribonuclease for cellular morphology, efficient control of mRNA levels, and virulence in B. abortus Overall, the results of this study advance our understanding of the critical roles of YbeY in the pathogenesis of the intracellular brucellae and expand our understanding of this highly conserved RNase.
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Blanchette KA, Wenke JC. Current therapies in treatment and prevention of fracture wound biofilms: why a multifaceted approach is essential for resolving persistent infections. J Bone Jt Infect 2018; 3:50-67. [PMID: 29761067 PMCID: PMC5949568 DOI: 10.7150/jbji.23423] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/16/2018] [Indexed: 12/13/2022] Open
Abstract
Traumatic orthopedic injuries, particularly extremity wounds, are a significant cause of morbidity. Despite prophylactic antibiotic treatment and surgical intervention, persistent infectious complications can and do occur. Persistent bacterial infections are often caused by biofilms, communities of antibiotic tolerant bacteria encased within a matrix. The structural and metabolic differences in this mode of growth make treatment difficult. Herein, we describe both established and novel, experimental treatments targeted at various stages of wound healing that are specifically aimed at reducing and eliminating biofilm bacteria. Importantly, the highly tolerant nature of these bacterial communities suggests that most singular approaches could be circumvented and a multifaceted, combinatorial approach will be the most effective strategy for treating these complicated infections.
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Affiliation(s)
| | - Joseph C Wenke
- US Army Institute of Surgical Research, Ft Sam Houston, TX
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118
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Sritharadol R, Hamada M, Kimura S, Ishii Y, Srichana T, Tateda K. Mupirocin at Subinhibitory Concentrations Induces Biofilm Formation in Staphylococcus aureus. Microb Drug Resist 2018; 24:1249-1258. [PMID: 29653478 DOI: 10.1089/mdr.2017.0290] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Mupirocin is a useful antibiotic against superficial skin infections. We compared the impact of mupirocin with a cephalosporin, a fluoroquinolone, an aminoglycoside, and a macrolide on planktonic cell growth and biofilm formation of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA). MATERIALS AND METHODS Minimum inhibitory concentration (MIC) of mupirocin was determined against S. aureus strains used in this study. Biofilm formation of S. aureus strains exposed to mupirocin was quantified by crystal violet staining assay. Moreover, biofilm structure and viability of the biofilm cells were visualized by Live/Dead staining assay. Biofilm-related gene expression was investigated by quantitative real-time PCR. RESULTS MRSA USA300 clone was resistant to mupirocin with MIC of 1,024 mg/L, while MRSA ATCC-43300 and MSSA ATCC-29213 were susceptible with MICs of 0.03 mg/L. Planktonic cell growth of the S. aureus strains was inhibited by mupirocin in a dose-dependent manner. However, some of the low concentrations of mupirocin less than the MICs promoted biofilm formation. Confocal laser scanning microscopy of the biofilm structures and cell viabilities showed established biofilms of slightly higher cell density in the mupirocin treated groups, especially in the MRSA USA300 clone. Gene expression of RNAIII in planktonic cells and biofilms of MRSA USA300 clone showed the highest upregulation after initial exposure to sub-MIC of mupirocin followed by downregulation, whereas the other antibiotics showed various fluctuations. CONCLUSION The results showed that subinhibitory concentrations of mupirocin promoted biofilm formation of S. aureus, in particular the MRSA USA300 clone.
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Affiliation(s)
- Rutthapol Sritharadol
- 1 Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University , Hat Yai, Songkhla, Thailand .,2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine , Tokyo, Japan
| | - Masakaze Hamada
- 2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine , Tokyo, Japan
| | - Soichiro Kimura
- 2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine , Tokyo, Japan
| | - Yoshikazu Ishii
- 2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine , Tokyo, Japan
| | - Teerapol Srichana
- 1 Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University , Hat Yai, Songkhla, Thailand
| | - Kazuhiro Tateda
- 2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine , Tokyo, Japan
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119
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Lee S, Kim S, Lee H, Ha J, Lee J, Choi Y, Oh H, Yoon Y, Choi KH. icaA Gene of Staphylococcus aureus Responds to NaCl, Leading to Increased Biofilm Formation. J Food Prot 2018; 81:412-416. [PMID: 29446687 DOI: 10.4315/0362-028x.jfp-17-238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to elucidate the role of the icaA gene in biofilm formation of Staphylococcus aureus exposed to NaCl. The icaA-deletion mutant of S. aureus ATCC 13565 was constructed with the temperature-sensitive plasmid pIMAY. Microtiter plate assays were performed to confirm biofilm formation for both the wild type and the mutant at 0% (control), 2, 4, and 6% NaCl. The microtiter plate assay revealed that biofilm formation by the wild type increased ( P < 0.05) as NaCl concentration increased, but biofilm formation of the mutant was not affected by NaCl concentration. Biofilm formation by the mutant was lower ( P < 0.05) than that by the wild type. These results indicate that icaA plays an important role in biofilm formation by S. aureus when the pathogen is exposed to NaCl.
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Affiliation(s)
- Soomin Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Sejeong Kim
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Heeyoung Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Jimyeong Ha
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Jeeyeon Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Yukyung Choi
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Hyemin Oh
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | | | - Kyoung-Hee Choi
- 2 Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54896, Korea
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120
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van Dissel D, Willemse J, Zacchetti B, Claessen D, Pier GB, van Wezel GP. Production of poly-β-1,6-N-acetylglucosamine by MatAB is required for hyphal aggregation and hydrophilic surface adhesion by Streptomyces. MICROBIAL CELL 2018; 5:269-279. [PMID: 29850464 PMCID: PMC5972031 DOI: 10.15698/mic2018.06.635] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Streptomycetes are multicellular filamentous microorganisms, and major producers of industrial enzymes and bioactive compounds such as antibiotics and anticancer drugs. The mycelial lifestyle plays an important role in the productivity during industrial fermentations. The hyphae of liquid-grown streptomycetes can self-aggregate into pellets, which hampers their industrial exploitation. Here we show that the Mat complex, which is required for pellet formation, catalyzes the synthesis of extracellular poly-β-1,6-N-acetylglucosamine (PNAG) in the model organisms Streptomyces coelicolor and Streptomyces lividans. Extracellular accumulation of PNAG allows Streptomyces to attach to hydrophilic surfaces, while attachment to hydrophobic surfaces requires a cellulase-degradable extracellular polymer (EPS) produced by CslA. Over-expression of matAB was sufficient to restore pellet formation to cslA null mutants of S. lividans. The two EPS systems together increase the robustness of mycelial pellets. These new insights allow better control of liquid-culture morphology of streptomycetes, which may be harnessed to improve growth and industrial exploitation of these highly versatile natural product and enzyme producers.
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Affiliation(s)
- Dino van Dissel
- Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Joost Willemse
- Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Boris Zacchetti
- Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Dennis Claessen
- Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Gilles P van Wezel
- Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
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121
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Kong C, Chee CF, Richter K, Thomas N, Abd Rahman N, Nathan S. Suppression of Staphylococcus aureus biofilm formation and virulence by a benzimidazole derivative, UM-C162. Sci Rep 2018; 8:2758. [PMID: 29426873 PMCID: PMC5807447 DOI: 10.1038/s41598-018-21141-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans – S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
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Affiliation(s)
- Cin Kong
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor, Malaysia.,Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, 43500, Semenyih, Selangor, Malaysia
| | - Chin-Fei Chee
- Nanotechnology & Catalysis Research Centre, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Katharina Richter
- Department of Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide, Adelaide, South Australia, Australia.,Adelaide Biofilm Test Facility, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - Nicky Thomas
- Adelaide Biofilm Test Facility, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia.,School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Noorsaadah Abd Rahman
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor, Malaysia.
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Roles of Staphylococcus aureus Mnh1 and Mnh2 Antiporters in Salt Tolerance, Alkali Tolerance, and Pathogenesis. J Bacteriol 2018; 200:JB.00611-17. [PMID: 29263099 PMCID: PMC5809693 DOI: 10.1128/jb.00611-17] [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: 10/11/2017] [Accepted: 12/08/2017] [Indexed: 01/19/2023] Open
Abstract
Staphylococcus aureus has three types of cation/proton antiporters. The type 3 family includes two multisubunit Na+/H+ (Mnh) antiporters, Mnh1 and Mnh2. These antiporters are clusters of seven hydrophobic membrane-bound protein subunits. Mnh antiporters play important roles in maintaining cytoplasmic pH in prokaryotes, enabling their survival under extreme environmental stress. In this study, we investigated the physiological roles and catalytic properties of Mnh1 and Mnh2 in S. aureus. Both Mnh1 and Mnh2 were cloned separately into a pGEM3Z+ vector in the antiporter-deficient KNabc Escherichia coli strain. The catalytic properties of the antiporters were measured in everted (inside out) vesicles. The Mnh1 antiporter exhibited a significant exchange of Na+/H+ cations at pH 7.5. Mnh2 showed a significant exchange of both Na+/H+ and K+/H+ cations, especially at pH 8.5. Under elevated salt conditions, deletion of the mnhA1 gene resulted in a significant reduction in the growth rate of S. aureus in the range of pH 7.5 to 9. Deletion of mnhA2 had similar effects but mainly in the range of pH 8.5 to 9.5. Double deletion of mnhA1 and mnhA2 led to a severe reduction in the S. aureus growth rate mainly at pH values above 8.5. The effects of functional losses of both antiporters in S. aureus were also assessed via their support of virulence in a mouse in vivo infection model. Deletion of the mnhA1 gene led to a major loss of S. aureus virulence in mice, while deletion of mnh2 led to no change in virulence. IMPORTANCE This study focuses on the catalytic properties and physiological roles of Mnh1 and Mnh2 cation/proton antiporters in S. aureus and their contributions under different stress conditions. The Mnh1 antiporter was found to have catalytic activity for Na+/H+ antiport, and it plays a significant role in maintaining halotolerance at pH 7.5 while the Mnh2 antiporter has catalytic antiporter activities for Na+/H+ and K+/H+ that have roles in both osmotolerance and halotolerance in S. aureus. Study of S. aureus with a single deletion of either mnhA1 or mnhA2 was assessed in an infection model of mice. The result shows that mnhA1, but not mnhA2, plays a major role in S. aureus virulence.
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Harraghy N, Seiler S, Jacobs K, Hannig M, Menger MD, Herrmann M. Advances in in Vitro and in Vivo Models for Studying the Staphylococcal Factors Involved in Implant Infections. Int J Artif Organs 2018; 29:368-78. [PMID: 16705605 DOI: 10.1177/039139880602900406] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Implant infections due to staphylococci are one of the greatest threats facing patients receiving implant devices. For many years researchers have sought to understand the mechanisms involved in the adherence of the bacterium to the implanted device and the formation of the unique structure, the biofilm, which protects the indwelling bacteria from the host defence and renders them resistant to antibiotic treatment. A major goal has been to develop in vitro and in vivo models that adequately reflect the real-life situation. From the simple microtiter plate assay and scanning electron microscopy, tools for studying adherence and biofilm formation have since evolved to include specialised equipment for studying adherence, flow cell systems, real-time analysis of biofilm formation using reporter gene assays both in vitro and in vivo, and a wide variety of animal models. In this article, we discuss advances in the last few years in selected in vitro and in vivo models as well as future developments in the study of adherence and biofilm formation by the staphylococci.
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Affiliation(s)
- N Harraghy
- Institute of Medical Microbiology and Hygiene, University of Saarland, Homburg/Saar, Germany.
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Neopane P, Nepal HP, Shrestha R, Uehara O, Abiko Y. In vitro biofilm formation by Staphylococcus aureus isolated from wounds of hospital-admitted patients and their association with antimicrobial resistance. Int J Gen Med 2018; 11:25-32. [PMID: 29403304 PMCID: PMC5779313 DOI: 10.2147/ijgm.s153268] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Introduction Staphylococcus aureus including methicillin-resistant S. aureus (MRSA) has the propensity to form biofilms, and causes significant mortality and morbidity in the patients with wounds. Our aim was to study the in vitro biofilm-forming ability of S. aureus isolated from wounds of hospitalized patients and their association with antimicrobial resistance. Materials and methods Forty-three clinical isolates of S. aureus were obtained from 150 pus samples using standard microbiological techniques. Biofilm formation in these isolates was detected by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby–Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test. Results Biofilm formation was observed in 30 (69.8%) and 28 (65.1%) isolates of S. aureus via TCP method and TM, respectively. Biofilm-producing S. aureus exhibited a higher incidence of antimicrobial resistance when compared with the biofilm nonproducers (P<0.05). Importantly, 86.7% of biofilm-producing S. aureus were multidrug resistant (MDR), whereas all the biofilm nonproducers were non-MDR (P<0.05). Large proportions (43.3%) of biofilm producers were identified as MRSA; however, none of the biofilm nonproducers were found to be MRSA (P<0.05). Conclusion Both the in vitro methods showed that S. aureus isolated from wound infection of hospitalized patients have high degree of biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by S. aureus and their antimicrobial resistance profile may lead to the early treatment of the wound infection.
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Affiliation(s)
- Puja Neopane
- Department of Microbiology, Chitwan Medical College and Teaching Hospital, Bharatpur, Nepal.,Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - Hari Prasad Nepal
- Department of Microbiology, Trinity School of Medicine, Kingstown, St. Vincent and the Grenadines
| | - Rojeet Shrestha
- School of Medicine, Washington University of Barbados, St. Philip, Barbados
| | - Osamu Uehara
- Division of Disease Control and Molecular Epidemiology, Department of Oral Growth and Development, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - Yoshihiro Abiko
- Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Japan
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Antimicrobial activity of 1,3,4-oxadiazole derivatives against planktonic cells and biofilm of Staphylococcus aureus. Future Med Chem 2018; 10:283-296. [PMID: 29334249 DOI: 10.4155/fmc-2017-0159] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
AIM Staphylococcus aureus is a major cause of severe hospital-acquired infections, and biofilm formation is an important part of staphylococcal pathogenesis. Therefore, developing new antimicrobial agents against both planktonic cells and biofilm of S. aureus is a major challenge. RESULTS Three 1,3,4-oxadiazole derivatives exhibited antimicrobial activity against seven S. aureus strains in vitro, with minimum inhibitory concentrations ranging from 4 to 32 μg/ml. At 4 × minimum inhibitory concentration, all compounds killed cells within 24 h, demonstrating bactericidal activity. In addition to their effects against planktonic cells, these compounds prevented biofilm formation in a dose-dependent manner, with inhibitory concentrations for biofilm formation ranging from 8 to 32 μg/ml. Interestingly, higher concentrations of these compounds were effective against mature biofilms and all compounds downregulated the transcription of the biofilm-related gene spa. CONCLUSION We report three new 1,3,4-oxadiazole derivatives that have bactericidal activity and could provide as alternatives to combat S. aureus.
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Manandhar S, Singh A, Varma A, Pandey S, Shrivastava N. Biofilm Producing Clinical Staphylococcus aureus Isolates Augmented Prevalence of Antibiotic Resistant Cases in Tertiary Care Hospitals of Nepal. Front Microbiol 2018. [PMID: 30538678 DOI: 10.3389/fmicb.2018.02749/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
Staphylococcus aureus, a notorious human pathogen, is a major cause of the community as well as healthcare associated infections. It can cause a diversity of recalcitrant infections mainly due to the acquisition of resistance to multiple drugs, its diverse range of virulence factors, and the ability to produce biofilm in indwelling medical devices. Such biofilm associated chronic infections often lead to increase in morbidity and mortality posing a high socio-economic burden, especially in developing countries. Since biofilm formation and antibiotic resistance function dependent on each other, detection of biofilm expression in clinical isolates would be advantageous in treatment decision. In this premise, we attempt to investigate the biofilm formation and its association with antibiotic resistance in clinical isolates from the patients visiting tertiary health care hospitals in Nepal. Bacterial cells isolated from clinical samples identified as S. aureus were examined for in-vitro biofilm production using both phenotypic and genotypic assays. The S. aureus isolates were also examined for susceptibility patterns of clinically relevant antibiotics as well as inducible clindamycin resistance using standard microbiological techniques and D-test, respectively. Among 161 S. aureus isolates, 131 (81.4%) were methicillin resistant S. aureus (MRSA) and 30 (18.6%) were methicillin sensitive S. aureus (MSSA) strains. Although a majority of MRSA strains (69.6%) showed inducible clindamycin resistance, almost all isolates (97% and 94%) were sensitive toward chloramphenicol and tetracycline, respectively. Detection of in vitro production of biofilm revealed the association of biofilm with methicillin as well as inducible clindamycin resistance among the clinical S. aureus isolates.
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Affiliation(s)
- Sarita Manandhar
- Tri-Chandra Multiple College, Tribhuvan University, Kathmandu, Nepal
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Anjana Singh
- Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Shanti Pandey
- The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Neeraj Shrivastava
- Amity Institute of Microbial Technology, Amity University, Noida, India
- Institute of Biotechnology, Zhejiang University, Hangzhou, China
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127
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Antimicrobial Effects of Violacein against Planktonic Cells and Biofilms of Staphylococcus aureus. Molecules 2017; 22:molecules22101534. [PMID: 28946655 PMCID: PMC6151432 DOI: 10.3390/molecules22101534] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/07/2017] [Accepted: 09/09/2017] [Indexed: 11/16/2022] Open
Abstract
Violacein is an indole compound, produced by Chromobacterium violaceum, a bacteria present in tropical and subtropical areas. Among its numerous biological activities, its antimicrobial potential stands out. This study aims to determine the antimicrobial activity of VIO on S. aureus in planktonic culture and biofilms. VIO showed excellent antimicrobial activity in inhibiting and killing S. aureus in planktonic cultures and biofilm formation. The minimum bactericidal concentration (5 μg/mL) of VIO caused the death of S. aureus after 3-4 h of exposure and the minimum inhibitory concentration (1.25 μg/mL) of VIO inhibited bacterial growth within the first 8 h of contact. Biofilm formation was also strongly inhibited by VIO (1.25 μg/mL), in contrast to the higher resistance verified for S. aureus in mature biofilm (40 μg/mL). The high bacterial metabolic activity favored VIO activity; however, the good activity observed during phases of reduced metabolism indicates that VIO action involves more than one mechanism. Thus, VIO is a promising molecule for the development of an antimicrobial drug for the eradication of S. aureus infections.
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128
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Blanchette KA, Prabhakara R, Shirtliff ME, Wenke JC. Inhibition of fracture healing in the presence of contamination by Staphylococcus aureus: Effects of growth state and immune response. J Orthop Res 2017; 35:1845-1854. [PMID: 28387956 DOI: 10.1002/jor.23573] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/29/2017] [Indexed: 02/04/2023]
Abstract
Extremity injuries comprise a significant portion of trauma, affecting quality of life, financial burden, and return to duty. Bacterial contamination is commonly associated with failure to heal, despite antibiotic treatment, suggesting that additional therapies must be developed to combat these complications. Treatment failure is likely due to the presence of resistant microbial communities known as biofilms. Biofilm bacteria are able to elicit a direct inhibition of healing through a multitude of known factors. However, they likely also inhibit healing through alteration of the inflammatory response. As inflammation is a critical step in fracture healing, how the presence of biofilm bacteria shifts this response to one that is suboptimal for healing is an important consideration that is currently understudied. The profile of inflammatory factors in response to biofilm bacteria is unique and distinct from those induced during normal healing or by planktonic bacteria alone. This review will examine the presence of inflammatory factors during normal healing and those induced by contaminating bacteria, and will discuss how these differences may ultimately lead to nonunion. Specifically, this review will focus on the Th1/Th2/Th17 type inflammatory responses and how shifts in the balance of these responses during infection can lead to both ineffective clearance and disruption of fracture healing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1845-1854, 2017.
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Affiliation(s)
- Krystle A Blanchette
- US Army Institute of Surgical Research, 3698 Chambers Pass STE B, JBSA Ft Sam, Houston 78234-7767, Texas
| | | | | | - Joseph C Wenke
- US Army Institute of Surgical Research, 3698 Chambers Pass STE B, JBSA Ft Sam, Houston 78234-7767, Texas
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129
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Abstract
The staphylococci comprise a diverse genus of Gram-positive, nonmotile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. Staphylococcus aureus and Staphylococcus epidermidis are major sources of hospital-acquired infections and are the most common causes of surgical site infections and medical device-associated bloodstream infections. The ability of staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device infections, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the staphylococcus genus and how this mode of growth impacts the host.
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130
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Woo SG, Lee SM, Lee SY, Lim KH, Ha EJ, Kim SH, Eom YB. The effectiveness of anti-biofilm and anti-virulence properties of dihydrocelastrol and dihydrocelastryl diacetate in fighting against methicillin-resistant Staphylococcus aureus. Arch Microbiol 2017; 199:1151-1163. [DOI: 10.1007/s00203-017-1386-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/06/2017] [Accepted: 05/04/2017] [Indexed: 01/03/2023]
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131
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Jørgensen NP, Hansen K, Andreasen CM, Pedersen M, Fuursted K, Meyer RL, Petersen E. Hyperbaric Oxygen Therapy is Ineffective as an Adjuvant to Daptomycin with Rifampicin Treatment in a Murine Model of Staphylococcus aureus in Implant-Associated Osteomyelitis. Microorganisms 2017; 5:microorganisms5020021. [PMID: 28441320 PMCID: PMC5488092 DOI: 10.3390/microorganisms5020021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 12/16/2022] Open
Abstract
Implant-associated infections caused by bacterial biofilms are difficult to treat. Surgical intervention is often necessary to cure the patient, as the antibiotic recalcitrance of biofilms renders them untreatable with conventional antibiotics. Intermittent hyperbaric oxygen treatment (HBOT) has been proposed as an adjuvant to conventional antibiotic treatment and it has been speculated that combining HBOT with antibiotics could improve treatment outcomes for biofilm infections. In this study we addressed whether HBOT could improve treatment outcomes of daptomycin and rifampicin combination therapy. The effect of HBOT on the treatment outcomes of daptomycin and rifampicin against implant-associated osteomyelitis was quantified in a murine model. In total, 80 mice were randomized into two groups receiving antibiotics, either alone or in combination with daily intermittent HBOT (304 kPa for 60 min) following injection of antibiotics. Treatment was initiated 11 days after animals were infected with Staphylococcus aureus and treatment duration was 14 days. We found that HBOT did not improve the cure rate and did not reduce the bacterial load on the implant surface or in the surrounding tissue. Cure rates of daptomycin + rifampicin were 40% in infected tibias and 75% for implants while cure rates for HBOT-daptomycin + rifampicin were 50% and 85%, respectively, which were not significantly higher (Fisher’s exact test). While it is encouraging that the combination of daptomycin and rifampicin is very effective, our study demonstrates that this efficacy cannot be improved by adjuvant HBOT.
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Affiliation(s)
- Nis Pedersen Jørgensen
- Department of Infectious Diseases, Aarhus University Hospital, 8200 Aarhus, Denmark.
- Department of Clinical Microbiology, Aarhus University Hospital, 8200 Aarhus, Denmark.
| | - Kasper Hansen
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University Hospital, 8200 Aarhus, Denmark.
| | | | - Michael Pedersen
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University Hospital, 8200 Aarhus, Denmark.
| | - Kurt Fuursted
- Microbiology and Infection Control, Statens Serum Institut, 2300 Copenhagen, Denmark.
| | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus, Denmark.
- Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.
| | - Eskild Petersen
- Department of Infectious Diseases, Aarhus University Hospital, 8200 Aarhus, Denmark.
- Department of Clinical Microbiology, Aarhus University Hospital, 8200 Aarhus, Denmark.
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132
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Lin LC, Shu JC, Chang SC, Ge MC, Liu TP, Chen CW, Lu JJ. Nucleotide Sequence Variations in Autolysis Genes of ST59 Methicillin-Resistant Staphylococcus aureus Isolates. Microb Drug Resist 2017; 23:940-948. [PMID: 28358616 DOI: 10.1089/mdr.2016.0098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Biofilm formation is a virulence factor of bacteria. The goal of this study was to understand the mechanisms of biofilm formation by methicillin-resistant Staphylococcus aureus (MRSA). Whole-genome sequencing of eight MRSA strains was performed to identify sequence variations in genes related to biofilm formation. Thirty-one genes involved in MRSA biofilm formation were analyzed and 11 amino acid sequence variations in four genes related to autolysis were found. These variations include E121D and H387 N in ArlS; Q117K, T424S, K428T, A509S, V752E, A754V, and T771A in Atl; T184K in CidC; and D251N in CidR. Among the 26 clinical MRSA isolates studied, 13 isolates were nonbiofilm producers and were found to harbor these mutations. Furthermore, all of these 13 isolates belonged to ST59. Ten of these 13 ST59 isolates became able to produce biofilms when they were incubated with extracellular DNA from MRSA N315. Results of this study suggest that sequence variations in arlS, atl, cidC, and cidR genes may render MRSA unable to produce biofilms. Further investigations are needed to correlate these sequence variations with the biofilm-forming ability of MRSA isolates.
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Affiliation(s)
- Lee-Chung Lin
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan
| | - Jwu-Ching Shu
- 2 Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Taoyuan, Taiwan
| | - Shih-Cheng Chang
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan .,2 Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Taoyuan, Taiwan
| | - Mao-Cheng Ge
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan
| | - Tsui-Ping Liu
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan
| | - Chien-Wei Chen
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan
| | - Jang-Jih Lu
- 1 Department of Laboratory Medicine, Chang Gung Memorial Hospital , Taoyuan, Taiwan .,2 Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Taoyuan, Taiwan
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133
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Environmental fluctuation governs selection for plasticity in biofilm production. ISME JOURNAL 2017; 11:1569-1577. [PMID: 28338673 DOI: 10.1038/ismej.2017.33] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/29/2016] [Accepted: 01/22/2017] [Indexed: 01/09/2023]
Abstract
Bacteria can grow in a free-swimming state, as planktonic cells, or in surface-attached communities, termed biofilms. The planktonic and biofilm growth modes differ dramatically with respect to spatial constraints, nutrient access, population density and cell-cell interactions. Fitness trade-offs underlie how successfully bacteria compete in each of these environments. Accordingly, some bacteria have evolved to be specialists in biofilm formation, while others specialize in planktonic growth. There are species, however, that possess flexible strategies: they can transition between the molecular programs required for biofilm formation and for planktonic growth. Such flexible strategies often sacrifice competitive ability against specialists in a given habitat. There is little exploration of the ecological conditions favoring the evolution of the flexible biofilm production strategy for bacteria in competition with specialist biofilm producers or specialist non-producers. Here, we study the human pathogen Vibrio cholerae, a flexible biofilm-former, as well as constitutive biofilm-producing and non-producing mutants. We assess the fitness of these strains under biofilm conditions, planktonic conditions and conditions that demand the ability to transition between the two growth modes. We show that, relative to the specialists, the wild type is superior at dispersal from biofilms to the planktonic phase; however, this capability comes at the expense of reduced competitive fitness against constitutive biofilm producers on surfaces. Wild-type V. cholerae can outcompete the constitutive biofilm producers and non-producers if habitat turnover is sufficiently frequent. Thus, selection for phenotypic flexibility in biofilm production depends on the frequency of environmental fluctuations encountered by bacteria.
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134
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Antibiotic tolerance and the alternative lifestyles of Staphylococcus aureus. Essays Biochem 2017; 61:71-79. [PMID: 28258231 DOI: 10.1042/ebc20160061] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/22/2016] [Accepted: 11/25/2016] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus has an incredible ability to survive, either by adapting to environmental conditions or defending against exogenous stress. Although there are certainly important genetic traits, in part this ability is provided by the breadth of modes of growth S. aureus can adopt. It has been proposed that while within their host, S. aureus survives host-generated and therapeutic antimicrobial stress via alternative lifestyles: a persister sub-population, through biofilm growth on host tissue or by growing as small colony variants (SCVs). Key to an understanding of chronic and relapsing S. aureus infections is determining the molecular basis for its switch to these quasi-dormant lifestyles. In a multicellular biofilm, the metabolically quiescent bacterial community additionally produces a highly protective extracellular polymeric substance (EPS). Furthermore, there are bacteria within a biofilm community that have an altered physiology potentially equivalent to persister cells. Recent studies have directly linked the cellular ATP production by persister cells as their key feature and the basis for their tolerance of a range of antibiotics. In clinical settings, SCVs of S. aureus have been observed for many years; when cultured, these cells form non-pigmented colonies and are approximately ten times smaller than their counterparts. Various genotypic factors have been identified in attempts to characterize S. aureus SCVs and different environmental stresses have been implicated as important inducers.
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135
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Rhodes CS, Alexander CM, Berretta JM, Courtney HS, Beenken KE, Smeltzer MS, Bumgardner JD, Haggard WO, Jennings JA. Evaluation of a chitosan-polyethylene glycol paste as a local antibiotic delivery device. World J Orthop 2017; 8:130-141. [PMID: 28251063 PMCID: PMC5314142 DOI: 10.5312/wjo.v8.i2.130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/20/2016] [Accepted: 11/17/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the efficacy of a chitosan/polyethylene glycol blended paste as a local antibiotic delivery device, particularly in musculoskeletal wounds.
METHODS Acidic (A) chitosan sponges and neutralized (N) chitosan/polyethylene glycol (PEG) blended sponges were combined in ratios of 3A:2N, 1A:1N, and 2A:3N; then hydrated with phosphate buffered saline to form a chitosan/PEG paste (CPP). Both in vitro and in vivo studies were conducted to determine the potential CPP has as a local antibiotic delivery device. In vitro biocompatibility was assessed by the cytotoxic response of fibroblast cells exposed to the experimental groups. Degradation rate was measured as the change in dry mass due to lysozyme based degradation over a 10-d period. The antibiotic elution profiles and eluate activity of CPP were evaluated over a 72-h period. To assess the in vivo antimicrobial efficacy of the CPP, antibiotic-loaded paste samples were exposed to subcutaneously implanted murine catheters inoculated with Staphylococcus aureus. Material properties of the experimental paste groups were evaluated by testing the ejection force from a syringe, as well as the adhesion to representative musculoskeletal tissue samples.
RESULTS The highly acidic CPP group, 3A:2N, displayed significantly lower cell viability than the control sponge group. The equally distributed group, 1A:1N, and the highly neutral group, 2A:3N, displayed similar cell viability to the control sponge group and are deemed biocompatible. The degradation studies revealed CPP is more readily degradable than the chitosan sponge control group. The antibiotic activity studies indicated the CPP groups released antibiotics at a constant rate and remained above the minimum inhibitory concentrations of the respective test bacteria for a longer time period than the control chitosan sponges, as well as displaying a minimized burst release. The in vivo functional model resulted in complete bacterial infection prevention in all catheters treated with the antibiotic loaded CPP samples. All experimental paste groups exhibited injectability and adhesive qualities that could be advantageous material properties for drug delivery to musculoskeletal injuries.
CONCLUSION CPP is an injectable, bioadhesive, biodegradable, and biocompatible material with potential to allow variable antibiotic loading and active, local antibiotic release to prevent bacterial contamination.
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136
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Torlak E, Korkut E, Uncu AT, Şener Y. Biofilm formation by Staphylococcus aureus isolates from a dental clinic in Konya, Turkey. J Infect Public Health 2017; 10:809-813. [PMID: 28214190 DOI: 10.1016/j.jiph.2017.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 12/01/2016] [Accepted: 01/07/2017] [Indexed: 11/26/2022] Open
Abstract
The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes' detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.
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Affiliation(s)
- Emrah Torlak
- Department of Molecular Biology and Genetics, Faculty of Science, Necmettin Erbakan University, Konya, Turkey.
| | - Emre Korkut
- Department of Pediatric Dentistry, Faculty of Dentistry, Necmettin Erbakan University, Konya, Turkey
| | - Ali T Uncu
- Department of Molecular Biology and Genetics, Faculty of Science, Necmettin Erbakan University, Konya, Turkey
| | - Yağmur Şener
- Department of Pediatric Dentistry, Faculty of Dentistry, Necmettin Erbakan University, Konya, Turkey
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137
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Dotto C, Lombarte Serrat A, Cattelan N, Barbagelata MS, Yantorno OM, Sordelli DO, Ehling-Schulz M, Grunert T, Buzzola FR. The Active Component of Aspirin, Salicylic Acid, Promotes Staphylococcus aureus Biofilm Formation in a PIA-dependent Manner. Front Microbiol 2017; 8:4. [PMID: 28167931 PMCID: PMC5253544 DOI: 10.3389/fmicb.2017.00004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 01/03/2017] [Indexed: 01/10/2023] Open
Abstract
Aspirin has provided clear benefits to human health. But salicylic acid (SAL) -the main aspirin biometabolite- exerts several effects on eukaryote and prokaryote cells. SAL can affect, for instance, the expression of Staphylococcus aureus virulence factors. SAL can also form complexes with iron cations and it has been shown that different iron chelating molecules diminished the formation of S. aureus biofilm. The aim of this study was to elucidate whether the iron content limitation caused by SAL can modify the S. aureus metabolism and/or metabolic regulators thus changing the expression of the main polysaccharides involved in biofilm formation. The exposure of biofilm to 2 mM SAL induced a 27% reduction in the intracellular free Fe2+ concentration compared with the controls. In addition, SAL depleted 23% of the available free Fe2+ cation in culture media. These moderate iron-limited conditions promoted an intensification of biofilms formed by strain Newman and by S. aureus clinical isolates related to the USA300 and USA100 clones. The slight decrease in iron bioavailability generated by SAL was enough to induce the increase of PIA expression in biofilms formed by methicillin-resistant as well as methicillin-sensitive S. aureus strains. S. aureus did not produce capsular polysaccharide (CP) when it was forming biofilms under any of the experimental conditions tested. Furthermore, SAL diminished aconitase activity and stimulated the lactic fermentation pathway in bacteria forming biofilms. The polysaccharide composition of S. aureus biofilms was examined and FTIR spectroscopic analysis revealed a clear impact of SAL in a codY-dependent manner. Moreover, SAL negatively affected codY transcription in mature biofilms thus relieving the CodY repression of the ica operon. Treatment of mice with SAL induced a significant increase of S aureus colonization. It is suggested that the elevated PIA expression induced by SAL might be responsible for the high nasal colonization observed in mice. SAL-induced biofilms may contribute to S. aureus infection persistence in vegetarian individuals as well as in patients that frequently consume aspirin.
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Affiliation(s)
- Cristian Dotto
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Andrea Lombarte Serrat
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Natalia Cattelan
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - María S Barbagelata
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Osvaldo M Yantorno
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - Daniel O Sordelli
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Tom Grunert
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Fernanda R Buzzola
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
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138
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Dhanireddy S, Neme S. Acute and Chronic Osteomyelitis. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00044-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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139
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Zhao X, Zhao F, Wang J, Zhong N. Biofilm formation and control strategies of foodborne pathogens: food safety perspectives. RSC Adv 2017. [DOI: 10.1039/c7ra02497e] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Foodborne pathogens are the main factors behind foodborne diseases and food poisoning and thus pose a great threat to food safety.
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Affiliation(s)
- Xihong Zhao
- Research Center for Environmental Ecology and Engineering
- Key Laboratory for Green Chemical Process of Ministry of Education
- Key Laboratory for Hubei Novel Reactor & Green Chemical Technology
- School of Chemical Engineering and Pharmacy
- Wuhan Institute of Technology
| | - Fenghuan Zhao
- Research Center for Environmental Ecology and Engineering
- Key Laboratory for Green Chemical Process of Ministry of Education
- Key Laboratory for Hubei Novel Reactor & Green Chemical Technology
- School of Chemical Engineering and Pharmacy
- Wuhan Institute of Technology
| | - Jun Wang
- College of Food Science and Engineering
- Qingdao Agricultural University
- Qingdao
- P. R. China
| | - Nanjing Zhong
- School of Food Science
- Guangdong Pharmaceutical University
- Zhongshan 528458
- P. R. China
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140
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Doulgeraki AI, Di Ciccio P, Ianieri A, Nychas GJE. Methicillin-resistant food-related Staphylococcus aureus: a review of current knowledge and biofilm formation for future studies and applications. Res Microbiol 2017; 168:1-15. [DOI: 10.1016/j.resmic.2016.08.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 07/18/2016] [Accepted: 08/05/2016] [Indexed: 12/18/2022]
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141
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Miller CL, Van Laar TA, Chen T, Karna SLR, Chen P, You T, Leung KP. Global transcriptome responses including small RNAs during mixed-species interactions with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Microbiologyopen 2016; 6. [PMID: 27868360 PMCID: PMC5458535 DOI: 10.1002/mbo3.427] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus mixed‐species biofilm infections are more resilient to biocide attacks compared to their single‐species counterparts. Therefore, this study used an in vitro model recapitulating bacterial burdens seen in in vivo infections to investigate the interactions of P. aeruginosa and S. aureus in biofilms. RNA sequencing (RNA‐seq) was utilized to identify the entire genomic response, both open reading frames (ORFs) and small RNAs (sRNAs), of each species. Using competitive indexes, transposon mutants validated uncharacterized PA1595 of P. aeruginosa and Panton–Valentine leukocidin ORFs of S. aureus are required for competitive success. Assessing spent media on biofilm development determined that the effects of these ORFs are not solely mediated by mechanisms of secretion. Unlike PA1595, leukocidin (lukS‐PV) mutants of S. aureus lack a competitive advantage through contact‐mediated mechanisms demonstrated by cross‐hatch assays. RNA‐seq results suggested that during planktonic mixed‐species growth there is a robust genomic response or active combat from both pathogens until a state of equilibrium is reached during the maturation of a biofilm. In mixed‐species biofilms, P. aeruginosa differentially expressed only 0.3% of its genome, with most ORFs necessary for growth and biofilm development, whereas S. aureus modulated approximately 5% of its genome, with ORFs suggestive of a phenotype of increased virulence and metabolic quiescence. Specific expression of characterized sRNAs aligned with the genomic response to presumably coordinate the adaptive changes necessary for this homeostatic mixed‐species biofilm and sRNAs may provide viable foci for the design of future therapeutics.
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Affiliation(s)
- Christine L Miller
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tricia A Van Laar
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tsute Chen
- The Forsyth Institute, Cambridge, MA, USA
| | - S L Rajasekhar Karna
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Ping Chen
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tao You
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Kai P Leung
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
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142
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Woo SG, Lee SY, Lee SM, Lim KH, Ha EJ, Eom YB. Activity of novel inhibitors of Staphylococcus aureus biofilms. Folia Microbiol (Praha) 2016; 62:157-167. [PMID: 27864779 DOI: 10.1007/s12223-016-0485-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 11/13/2016] [Indexed: 12/27/2022]
Abstract
Staphylococcus aureus is one of the most important pathogens causing chronic biofilm infections. These are becoming more difficult to treat owing to drug resistance, particularly because S. aureus biofilms limit the efficacy of antimicrobial agents, leading to high morbidity and mortality. In the present study, we screened for inhibitors of S. aureus biofilm formation using a natural product library from the Korea Chemical Bank (KCB). Screening by crystal violet-based biomass staining assay identified hit compounds. Further examination of antibiofilm properties of these compounds was conducted and led to the identification of celastrol and telithromycin. In vitro, both celastrol and telithromycin were toxic to planktonic S. aureus and also active against a clinical methicillin-resistant S. aureus (MRSA) isolate. The effect of the compounds on preformed biofilms of clinical MRSA isolates was evaluated by confocal laser scanning microscopy (CLSM), which revealed the absence of typical biofilm architecture. In addition, celastrol and telithromycin inhibited the production of extracellular protein at selected sub-MIC concentrations, which revealed the reduced extracellular polymeric substance (EPS) secretion. Celastrol exhibited greater cytotoxicity than telithromycin. These data suggest that the hit compounds, especially telithromycin, could be considered novel inhibitors of S. aureus biofilm. Although the mechanisms of the effects on S. aureus biofilms are not fully understood, our data suggest that telithromycin could be a useful adjuvant therapeutic agent for S. aureus biofilm-related infections.
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Affiliation(s)
- Seung-Gyun Woo
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - So-Yeon Lee
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - So-Min Lee
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Kyoung-Hee Lim
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Eun-Ju Ha
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Yong-Bin Eom
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea.
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea.
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143
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Tan XE, Neoh HM, Looi ML, Chin SF, Cui L, Hiramatsu K, Hussin S, Jamal R. Activated ADI pathway: the initiator of intermediate vancomycin resistance in Staphylococcus aureus. Can J Microbiol 2016; 63:260-264. [PMID: 28059579 DOI: 10.1139/cjm-2016-0439] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Comparative proteomic profiling between 2 vancomycin-intermediate Staphylococcus aureus (VISA) strains, Mu50Ω-vraSm and Mu50Ω-vraSm-graRm, and vancomycin-susceptible S. aureus (VSSA) strain Mu50Ω revealed upregulated levels of catabolic ornithine carbamoyltransferase (ArcB) of the arginine catabolism pathway in VISA strains. Subsequent analyses showed that the VISA strains have higher levels of cellular ATP and ammonia, which are by-products of arginine catabolism, and displayed thicker cell walls. We postulate that elevated cytoplasmic ammonia and ATP molecules, resulting from activated arginine catabolism upon acquisition of vraS and graR mutations, are important requirements facilitating cell wall biosynthesis, thereby contributing to thickened cell wall and consequently reduced vancomycin susceptibility in VISA strains.
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Affiliation(s)
- Xin-Ee Tan
- a UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Malaysia
| | - Hui-Min Neoh
- a UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Malaysia.,b Department of Bacteriology, School of Medicine, Juntendo University, Japan
| | - Mee-Lee Looi
- a UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Malaysia.,c Taylor's University Lakeside Campus, School of Biosciences, Malaysia
| | - Siok Fong Chin
- a UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Malaysia
| | - Longzhu Cui
- d Division of Bacteriology, Department of Infection and Immunity, School of Medicine, Jichi Medical University, Japan
| | - Keiichi Hiramatsu
- b Department of Bacteriology, School of Medicine, Juntendo University, Japan
| | - Salasawati Hussin
- e Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia, Malaysia
| | - Rahman Jamal
- a UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Malaysia
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144
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Macroscopic amyloid fiber formation by staphylococcal biofilm associated SuhB protein. Biophys Chem 2016; 217:32-41. [DOI: 10.1016/j.bpc.2016.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/04/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022]
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145
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Gel-Entrapped Staphylococcus aureus Bacteria as Models of Biofilm Infection Exhibit Growth in Dense Aggregates, Oxygen Limitation, Antibiotic Tolerance, and Heterogeneous Gene Expression. Antimicrob Agents Chemother 2016; 60:6294-301. [PMID: 27503656 DOI: 10.1128/aac.01336-16] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/03/2016] [Indexed: 11/20/2022] Open
Abstract
An experimental model that mimicked the structure and characteristics of in vivo biofilm infections, such as those occurring in the lung or in dermal wounds where no biomaterial surface is present, was developed. In these infections, microbial biofilm forms as cell aggregates interspersed in a layer of mucus or host matrix material. This structure was modeled by filling glass capillary tubes with an agarose gel that had been seeded with Staphylococcus aureus bacteria and then incubating the gel biofilm in medium for up to 30 h. Confocal microscopy showed that the bacteria formed in discrete pockets distributed throughout the gel matrix. These aggregates enlarged over time and also developed a size gradient, with the clusters being larger near the nutrient- and oxygen-supplied interface and smaller at greater depths. Bacteria entrapped in gels for 24 h grew slowly (specific growth rate, 0.06 h(-1)) and were much less susceptible to oxacillin, minocycline, or ciprofloxacin than planktonic cells. Microelectrode measurements showed that the oxygen concentration decreased with depth into the gel biofilm, falling to values less than 3% of air saturation at depths of 500 μm. An anaerobiosis-responsive green fluorescent protein reporter gene for lactate dehydrogenase was induced in the region of the gel where the measured oxygen concentrations were low, confirming biologically relevant hypoxia. These results show that the gel biofilm model captures key features of biofilm infection in mucus or compromised tissue: formation of dense, distinct aggregates, reduced specific growth rates, local hypoxia, and antibiotic tolerance.
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146
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Crosby HA, Kwiecinski J, Horswill AR. Staphylococcus aureus Aggregation and Coagulation Mechanisms, and Their Function in Host-Pathogen Interactions. ADVANCES IN APPLIED MICROBIOLOGY 2016; 96:1-41. [PMID: 27565579 DOI: 10.1016/bs.aambs.2016.07.018] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human commensal bacterium Staphylococcus aureus can cause a wide range of infections ranging from skin and soft tissue infections to invasive diseases like septicemia, endocarditis, and pneumonia. Muticellular organization almost certainly contributes to S. aureus pathogenesis mechanisms. While there has been considerable focus on biofilm formation and its role in colonizing prosthetic joints and indwelling devices, less attention has been paid to nonsurface-attached group behavior like aggregation and clumping. S. aureus is unique in its ability to coagulate blood, and it also produces multiple fibrinogen-binding proteins that facilitate clumping. Formation of clumps, which are large, tightly packed groups of cells held together by fibrin(ogen), has been demonstrated to be important for S. aureus virulence and immune evasion. Clumps of cells are able to avoid detection by the host's immune system due to a fibrin(ogen) coat that acts as a shield, and the size of the clumps facilitates evasion of phagocytosis. In addition, clumping could be an important early step in establishing infections that involve tight clusters of cells embedded in host matrix proteins, such as soft tissue abscesses and endocarditis. In this review, we discuss clumping mechanisms and regulation, as well as what is known about how clumping contributes to immune evasion.
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Affiliation(s)
- H A Crosby
- University of Iowa, Iowa City, IA, United States
| | - J Kwiecinski
- University of Iowa, Iowa City, IA, United States
| | - A R Horswill
- University of Iowa, Iowa City, IA, United States
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147
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Xu Z, Liang Y, Lin S, Chen D, Li B, Li L, Deng Y. Crystal Violet and XTT Assays on Staphylococcus aureus Biofilm Quantification. Curr Microbiol 2016; 73:474-82. [DOI: 10.1007/s00284-016-1081-1] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 05/06/2016] [Indexed: 11/24/2022]
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148
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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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149
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Shayani Rad M, Khameneh B, Sabeti Z, Mohajeri SA, Fazly Bazzaz BS. Antibacterial Activity of Silver Nanoparticle-Loaded Soft Contact Lens Materials: The Effect of Monomer Composition. Curr Eye Res 2016; 41:1286-1293. [DOI: 10.3109/02713683.2015.1123726] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Maryam Shayani Rad
- Student Research Committee (SRC), Mashhad University of Medical Sciences, Mashhad, Iran
- Targeted Drug Delivery Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bahman Khameneh
- Department of Pharmaceutical Control, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra Sabeti
- Biotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Ahmad Mohajeri
- Targeted Drug Delivery Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bibi Sedigheh Fazly Bazzaz
- Biotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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150
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Gautam A, Sharma A, Jaiswal S, Fatma S, Arora V, Iquebal MA, Nandi S, Sundaray JK, Jayasankar P, Rai A, Kumar D. Development of Antimicrobial Peptide Prediction Tool for Aquaculture Industries. Probiotics Antimicrob Proteins 2016; 8:141-9. [DOI: 10.1007/s12602-016-9215-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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