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Inglis TJJ, Paton TF, Kopczyk MK, Mulroney KT, Carson CF. Same-day antimicrobial susceptibility test using acoustic-enhanced flow cytometry visualized with supervised machine learning. J Med Microbiol 2020; 69:657-669. [PMID: 31665100 PMCID: PMC7451041 DOI: 10.1099/jmm.0.001092] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/23/2019] [Indexed: 11/18/2022] Open
Abstract
Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact treatment. This proof-of-concept study assessed the feasibility of using machine-learning techniques for analysis of data produced by the flow cytometer-assisted antimicrobial susceptibility test (FAST) method we developed.Methods. We used machine learning to assess the effect of antimicrobial agents on bacteria, comparing FAST results with broth microdilution (BMD) antimicrobial susceptibility tests (ASTs). We used Escherichia coli (1), Klebsiella pneumoniae (1) and Staphylococcus aureus (2) strains to develop the machine-learning algorithm, an expanded panel including these plus E. coli (2), K. pneumoniae (3), Proteus mirabilis (1), Pseudomonas aeruginosa (1), S. aureus (2) and Enterococcus faecalis (1), tested against FAST and BMD (Sensititre, Oxoid), then two representative isolates directly from blood cultures.Results. Our data machines defined an antibiotic-unexposed population (AUP) of bacteria, classified the FAST result by antimicrobial concentration range, and determined a concentration-dependent antimicrobial effect (CDE) to establish a predicted inhibitory concentration (PIC). Reference strains of E. coli, K. pneumoniae and S. aureus tested with different antimicrobial agents demonstrated concordance between BMD results and machine-learning analysis (CA, categoric agreement of 91 %; EA, essential agreement of 100 %). CA was achieved in 35 (83 %) and EA in 28 (67 %) by machine learning on first pass in a challenge panel of 27 Gram-negative and 15 Gram-positive ASTs. Same-day AST results were obtained from clinical E. coli (1) and S. aureus (1) isolates.Conclusions. The combination of machine learning with the FAST method generated same-day AST results and has the potential to aid early antimicrobial treatment decisions, stewardship and detection of resistance.
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Affiliation(s)
- Timothy J. J. Inglis
- School of Medicine, Faculty of Health and Medical Sciences, the University of Western Australia, Perth, Australia
- The Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, Faculty of Health and Medical Sciences, the University of Western Australia, Perth, Australia
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands WA, Australia
| | - Teagan F. Paton
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands WA, Australia
| | - Malgorzata K. Kopczyk
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands WA, Australia
| | - Kieran T. Mulroney
- School of Medicine, Faculty of Health and Medical Sciences, the University of Western Australia, Perth, Australia
- The Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, Faculty of Health and Medical Sciences, the University of Western Australia, Perth, Australia
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands WA 6009, Australia
| | - Christine F. Carson
- The Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, Faculty of Health and Medical Sciences, the University of Western Australia, Perth, Australia
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Carson CF, Inglis TJJ. Air sampling to assess potential generation of aerosolized viable bacteria during flow cytometric analysis of unfixed bacterial suspensions. Gates Open Res 2018; 1:2. [PMID: 29608197 PMCID: PMC5873458 DOI: 10.12688/gatesopenres.12759.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2018] [Indexed: 01/31/2024] Open
Abstract
This study investigated aerosolized viable bacteria in a university research laboratory during operation of an acoustic-assisted flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. The aim was to assess the risk associated with use of an acoustic-assisted flow cytometer analyzing unfixed bacterial suspensions. Air sampling in a nearby clinical laboratory was conducted during the same period to provide context for the existing background of microorganisms that would be detected in the air. The three species of bacteria undergoing analysis by flow cytometer in the research laboratory were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. None of these was detected from multiple 1000 L air samples acquired in the research laboratory environment. The main cultured bacteria in both locations were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in laboratory air by personnel movements during routine laboratory activities. The concentrations of bacteria detected in research laboratory air samples were reduced after interventional cleaning measures were introduced and were lower than those in the diagnostic clinical microbiology laboratory. We conclude that our flow cytometric analyses of unfixed suspensions of K. pneumoniae, B. thailandensis and S. pneumoniae do not pose a risk to cytometer operators or other personnel in the laboratory but caution against extrapolation of our results to other bacteria and/or different flow cytometric experimental procedures.
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Affiliation(s)
- Christine F Carson
- School of Biomedical Sciences (M504), Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia
| | - Timothy JJ Inglis
- School of Biomedical Sciences (M504), Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia
- School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia
- Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia
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Carson CF, Inglis TJ. Air sampling to assess potential generation of aerosolized viable bacteria during flow cytometric analysis of unfixed bacterial suspensions. Gates Open Res 2018; 1:2. [PMID: 29608197 PMCID: PMC5873458 DOI: 10.12688/gatesopenres.12759.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2018] [Indexed: 11/20/2022] Open
Abstract
This study investigated aerosolized viable bacteria in a university research laboratory during operation of an acoustic-assisted flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. The aim was to assess the risk associated with use of an acoustic-assisted flow cytometer analyzing unfixed bacterial suspensions. Air sampling in a nearby clinical laboratory was conducted during the same period to provide context for the existing background of microorganisms that would be detected in the air. The three species of bacteria undergoing analysis by flow cytometer in the research laboratory were
Klebsiella pneumoniae, Burkholderia thailandensis and
Streptococcus pneumoniae. None of these was detected from multiple 1000 L air samples acquired in the research laboratory environment. The main cultured bacteria in both locations were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in laboratory air by personnel movements during routine laboratory activities. The concentrations of bacteria detected in research laboratory air samples were reduced after interventional cleaning measures were introduced and were lower than those in the diagnostic clinical microbiology laboratory. We conclude that our flow cytometric analyses of unfixed suspensions of
K. pneumoniae, B. thailandensis and
S. pneumoniae do not pose a risk to cytometer operators or other personnel in the laboratory but caution against extrapolation of our results to other bacteria and/or different flow cytometric experimental procedures.
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Affiliation(s)
- Christine F Carson
- School of Biomedical Sciences (M504), Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia
| | - Timothy Jj Inglis
- School of Biomedical Sciences (M504), Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia.,School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia.,Department of Microbiology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia
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Popowicz ND, Lansley SM, Cheah HM, Kay ID, Carson CF, Waterer GW, Paton JC, Brown JS, Lee YCG. Human pleural fluid is a potent growth medium for Streptococcus pneumoniae. PLoS One 2017; 12:e0188833. [PMID: 29190798 PMCID: PMC5708656 DOI: 10.1371/journal.pone.0188833] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/14/2017] [Indexed: 12/03/2022] Open
Abstract
Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×106CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063–9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was observed in pleural fluid before and after removal of its cellular content, p = 0.728. S. pneumoniae (D39 strain) wild-type, and derivatives (n = 12), each with mutation(s) in a different gene required for full virulence were inoculated into human pleural fluid (n = 8). S. pneumoniae with pneumococcal surface antigen A (ΔpsaA) mutation failed to grow (2207-fold lower than wild-type), p<0.001, however growth was restored with manganese supplementation. Growth of other common respiratory pathogens (n = 14) across pleural fluid samples (n = 7) was variable and inconsistent, with some strains failing to grow. We establish for the first time that pleural fluid is a potent growth medium for S. pneumoniae and proliferation is dependent on the PsaA surface protein and manganese.
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Affiliation(s)
- Natalia D. Popowicz
- Pharmacy Department, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
- Division of Medicine, University of Western Australia, Perth, Western Australia, Australia
- Institute for Respiratory Health, University of Western Australia, Perth, Western Australia, Australia
| | - Sally M. Lansley
- Institute for Respiratory Health, University of Western Australia, Perth, Western Australia, Australia
| | - Hui M. Cheah
- Institute for Respiratory Health, University of Western Australia, Perth, Western Australia, Australia
| | - Ian D. Kay
- Department of Microbiology and Infectious Diseases, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Christine F. Carson
- Division of Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Grant W. Waterer
- Division of Medicine, University of Western Australia, Perth, Western Australia, Australia
- Respiratory Department, Royal Perth Hospital, Perth, Western Australia, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, South Australia, Australia
| | - Jeremy S. Brown
- Centre for Inflammation and Tissue Repair, Respiratory Medicine, University College London, London, England
| | - Y. C. Gary Lee
- Division of Medicine, University of Western Australia, Perth, Western Australia, Australia
- Institute for Respiratory Health, University of Western Australia, Perth, Western Australia, Australia
- Respiratory Department, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
- * E-mail:
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McGuire AL, Mulroney KT, Carson CF, Ram R, Morahan G, Chakera A. Analysis of early mesothelial cell responses to Staphylococcus epidermidis isolated from patients with peritoneal dialysis-associated peritonitis. PLoS One 2017; 12:e0178151. [PMID: 28542390 PMCID: PMC5443531 DOI: 10.1371/journal.pone.0178151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 05/08/2017] [Indexed: 02/06/2023] Open
Abstract
The major complication of peritoneal dialysis (PD) is the development of peritonitis, an infection within the abdominal cavity, primarily caused by bacteria. PD peritonitis is associated with significant morbidity, mortality and health care costs. Staphylococcus epidermidis is the most frequently isolated cause of PD-associated peritonitis. Mesothelial cells are integral to the host response to peritonitis, and subsequent clinical outcomes, yet the effects of infection on mesothelial cells are not well characterised. We systematically investigated the early mesothelial cell response to clinical and reference isolates of S. epidermidis using primary mesothelial cells and the mesothelial cell line Met-5A. Using an unbiased whole genome microarray, followed by a targeted panel of genes known to be involved in the human antibacterial response, we identified 38 differentially regulated genes (adj. p-value < 0.05) representing 35 canonical pathways after 1 hour exposure to S. epidermidis. The top 3 canonical pathways were TNFR2 signaling, IL-17A signaling, and TNFR1 signaling (adj. p-values of 0.0012, 0.0012 and 0.0019, respectively). Subsequent qPCR validation confirmed significant differences in gene expression in a number of genes not previously described in mesothelial cell responses to infection, with heterogeneity observed between clinical isolates of S. epidermidis, and between Met-5A and primary mesothelial cells. Heterogeneity between different S. epidermidis isolates suggests that specific virulence factors may play critical roles in influencing outcomes from peritonitis. This study provides new insights into early mesothelial cell responses to infection with S. epidermidis, and confirms the importance of validating findings in primary mesothelial cells.
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Affiliation(s)
- Amanda L. McGuire
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
- * E-mail:
| | - Kieran T. Mulroney
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
| | - Christine F. Carson
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
| | - Ramesh Ram
- Centre for Diabetes Research, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
| | - Grant Morahan
- Centre for Diabetes Research, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
| | - Aron Chakera
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
- Department of Renal Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
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Carson CF, Ash O, Chakera A. In vitro data support the investigation of vinegar as an antimicrobial agent for PD-associated Pseudomonas exit site infections. Nephrology (Carlton) 2017; 22:179-181. [PMID: 28064452 DOI: 10.1111/nep.12848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 07/03/2016] [Indexed: 11/29/2022]
Abstract
Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and can lead to peritonitis and/or modality failure. Effective alternative or adjunct non-antibiotic antimicrobial agents could improve treatment as well as reduce the use of antibiotics and contribute to a reduction in antibiotic selection pressure and the further development of antibiotic resistance. Vinegar is popularly promoted as a topical antimicrobial agent and has been recommended as an adjunct treatment for Pseudomonas exit site infections in PD patients. Systematic empirical data on the susceptibility of pseudomonads to vinegar are lacking. This study aimed to determine the susceptibility to vinegar of 57 isolates of Pseudomonas. The MICs and MBCs of four vinegars were determined for clinical, environmental and/or reference isolates of P. aeruginosa (n = 34), P. fluorescens (n = 11) and P. putida (n = 12) using a broth microdilution method. The MIC90 and MBC90 were also determined for each species. The MIC90 of all four vinegars against P. aeruginosa was 2% (vol/vol). The MBC90 was 8%. The MIC90 s for P. fluorescens and P. putida were also 2%. The MIC90 s were 4%. Dilutions of vinegar recommended for the treatment of Pseudomonas exit site infections have in vitro activity against these notoriously resistant bacteria. In light of increasing rates of antibiotic resistance and the need to reduce antibiotic selection pressure as part of good antibiotic stewardship, the efficacy of vinegar, or its active constituent acetic acid, for the treatment of Pseudomonas exit site infections should be investigated further.
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Affiliation(s)
- Christine F Carson
- School of Medicine and Pharmacology, The University of Western Australia (M503), Crawley, Australia.,Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Australia
| | - Oliver Ash
- School of Medicine, The University of Notre Dame Australia, Fremantle, Australia
| | - Aron Chakera
- School of Medicine and Pharmacology, The University of Western Australia (M503), Crawley, Australia.,Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Australia.,Renal Unit, Sir Charles Gairdner Hospital, Nedlands, Australia
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Thomas J, Carson CF, Peterson GM, Walton SF, Hammer KA, Naunton M, Davey RC, Spelman T, Dettwiller P, Kyle G, Cooper GM, Baby KE. Therapeutic Potential of Tea Tree Oil for Scabies. Am J Trop Med Hyg 2016; 94:258-266. [PMID: 26787146 PMCID: PMC4751955 DOI: 10.4269/ajtmh.14-0515] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 05/08/2015] [Indexed: 11/20/2022] Open
Abstract
Globally, scabies affects more than 130 million people at any time. In the developed world, outbreaks in health institutions and vulnerable communities result in a significant economic burden. A review of the literature demonstrates the emergence of resistance toward classical scabicidal treatments and the lack of effectiveness of currently available scabicides in reducing the inflammatory skin reactions and pyodermal progression that occurs in predisposed patient cohorts. Tea tree oil (TTO) has demonstrated promising acaricidal effects against scabies mites in vitro and has also been successfully used as an adjuvant topical medication for the treatment of crusted scabies, including cases that did not respond to standard treatments. Emerging acaricide resistance threatens the future usefulness of currently used gold standard treatments (oral ivermectin and topical permethrin) for scabies. The imminent development of new chemical entities is doubtful. The cumulative acaricidal, antibacterial, antipruritic, anti-inflammatory, and wound healing effects of TTO may have the potential to successfully reduce the burden of scabies infection and the associated bacterial complications. This review summarizes current knowledge on the use of TTO for the treatment of scabies. On the strength of existing data for TTO, larger scale, randomized controlled clinical trials are warranted.
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Affiliation(s)
- Jackson Thomas
- University of Canberra, Faculty of Health, Bruce, Canberra, Australia; Faculty of Health, University of Tasmania, Hobart, Tasmania, Australia, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia; School of Medicine and Pharmacology, The University of Western Australia and Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, Western Australia; Burnet Institute, Melbourne, Victoria, Australia; School of Medicine, Flinders University, Katherine, Northern Territory, Australia; Private Practice, Charnwood, Canberra, Australia
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McGuire AL, Carson CF, Inglis TJJ, Chakera A. Effects of a Statewide Protocol for the Management of Peritoneal Dialysis-Related Peritonitis on Microbial Profiles and Antimicrobial Susceptibilities: A Retrospective Five-Year Review. Perit Dial Int 2015; 35:722-8. [PMID: 26152579 DOI: 10.3747/pdi.2014.00117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 08/26/2014] [Indexed: 11/15/2022] Open
Abstract
UNLABELLED ♦ BACKGROUND Peritonitis is a major complication of peritoneal dialysis (PD) and is associated with significant morbidity and mortality. Early empirical antibiotic therapy is recommended, with the choice of agents guided by local resistance patterns. As routine use of specific antimicrobial agents can drive resistance, regular assessment of causative organisms and their susceptibility to empirical therapy is essential. ♦ METHODS We conducted a retrospective review of all PD peritonitis cases and positive PD fluid cultures obtained over a 5-year period in Western Australia following the introduction of a statewide protocol for the initial management of PD peritonitis with intraperitoneal vancomycin and gentamicin. ♦ RESULTS The incidence of PD peritonitis decreased from 1 in 16 patient months (0.75/year at risk) to 1 in 29 patient months (0.41/year at risk) over the 5 years. There were 1,319 culture-positive samples and 1,069 unique isolates identified. Gram-positive bacteria accounted for 69.9% of positive cultures, with vancomycin resistance averaging 2% over the study period. Gram-negative bacteria accounted for 25.4% of positive cultures, with gentamicin resistance identified in an average of 8% of organisms. No increase in antimicrobial resistance to vancomycin or gentamicin occurred over the 5 years and there was no change in the proportion of gram-positive (69.9%), gram-negative (25.4%) or fungal (4.4%) organisms causing PD peritonitis. ♦ CONCLUSIONS Over time, the peritonitis rates have dramatically improved although the profile of causative organisms remains similar. Empirical treatment of PD peritonitis with intraperitoneal vancomycin and gentamicin remains efficacious, with high levels of susceptibility and no evidence that the introduction of this statewide empirical PD peritonitis treatment protocol is driving resistance to these agents.
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Affiliation(s)
- Amanda L McGuire
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia
| | - Christine F Carson
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia
| | - Timothy J J Inglis
- Department of Microbiology, PathWest Laboratory Medicine WA, Nedlands, Western Australia School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia
| | - Aron Chakera
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia Renal Department, Sir Charles Gairdner Hospital, Nedlands, Western Australia
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Thomas J, Peterson GM, Walton SF, Carson CF, Naunton M, Baby KE. Scabies: an ancient global disease with a need for new therapies. BMC Infect Dis 2015; 15:250. [PMID: 26123073 PMCID: PMC4487193 DOI: 10.1186/s12879-015-0983-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 06/10/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Scabies is an ancient disease (documented as far back as 2500 years ago). It affects about 300 million people annually worldwide, and the prevalence is as high as about 60% in Indigenous and Torres Strait Islander children in Australia. This is more than six times the rate seen in the rest of the developed world. Scabies is frequently complicated by bacterial infection leading to the development of skin sores and other more serious consequences such as septicaemia and chronic heart and kidney diseases. This causes a substantial social and economic burden especially in resource poor communities around the world. DISCUSSION Very few treatment options are currently available for the management of scabies infection. In this manuscript we briefly discuss the clinical consequences of scabies and the problems found (studies conducted in Australia) with the currently used topical and oral treatments. Current scabies treatment options are fairly ineffective in preventing treatment relapse, inflammatory skin reactions and associated bacterial skin infections. None have ovicidal, antibacterial, anti-inflammatory and/or anti-pruritic properties. Treatments which are currently available for scabies can be problematic with adverse effects and perhaps of greater concern the risk of treatment failure. The development of new chemical entities is doubtful in the near future. Though there may be potential for immunological control, the development of a vaccine or other immunotherapy modalities may be decades away. The emergence of resistance among scabies mites to classical scabicides and ineffectiveness of current treatments (in reducing inflammatory skin reactions and secondary bacterial infections associated with scabies), raise serious concerns regarding current therapy. Treatment adherence difficulties, and safety and efficacy uncertainties in the young and elderly, all signal the need to identify new treatments for scabies.
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Affiliation(s)
- Jackson Thomas
- Faculty of Health, University of Canberra, Bruce, 2601, ACT, Australia.
| | - Greg M Peterson
- Faculty of Health, University of Tasmania, Hobart, 7005, TAS, Australia.
| | - Shelley F Walton
- Faculty of Science; Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, 4558, QLD, Australia.
| | - Christine F Carson
- School of Medicine and Pharmacology (M503), The University of Western Australia, Nedlands, 6009, WA, Australia.
- Translational Renal Research Group, Harry Perkins Institute of Medical Research, Nedlands, 6009, WA, Australia.
| | - Mark Naunton
- Faculty of Health, University of Canberra, Bruce, 2601, ACT, Australia.
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Carson CF, Tisserand R, Larkman T. Lack of evidence that essential oils affect puberty. Reprod Toxicol 2014; 44:50-1. [PMID: 24556344 DOI: 10.1016/j.reprotox.2013.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 11/25/2022]
Affiliation(s)
- Christine F Carson
- School of Pathology & Laboratory Medicine (M504), The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia.
| | | | - Tony Larkman
- ATTIA Ltd., PO Box 903, Casino, NSW 2470, Australia.
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Thomsen NA, Hammer KA, Riley TV, Van Belkum A, Carson CF. Effect of habituation to tea tree (Melaleuca alternifolia) oil on the subsequent susceptibility of Staphylococcus spp. to antimicrobials, triclosan, tea tree oil, terpinen-4-ol and carvacrol. Int J Antimicrob Agents 2013; 41:343-51. [DOI: 10.1016/j.ijantimicag.2012.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
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Sudjana AN, Carson CF, Carson KC, Riley TV, Hammer KA. Candida albicans adhesion to human epithelial cells and polystyrene and formation of biofilm is reduced by sub-inhibitory Melaleuca alternifolia (tea tree) essential oil. Med Mycol 2012; 50:863-70. [PMID: 22587732 DOI: 10.3109/13693786.2012.683540] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study investigated the effects of the volatile terpene-rich oil from Melaleuca alternifolia (tea tree oil) on the formation of biofilms and the adhesion of C. albicans cells to both biotic and abiotic surfaces. Biofilm formation on polystyrene was significantly inhibited for 70% of the isolates at the lowest test concentration of 0.016% of tea tree oil (TTO) when quantified by XTT and 40% of isolates when measured by crystal violet staining. Adhesion to polystyrene, quantified by crystal violet staining, was significantly reduced for 3 isolates at 0.031%, 6 isolates at 0.062% and 0.125% and for all 7 isolates at 0.25% TTO. Reductions in adhesion were not due to loss of viability (at concentrations of ≤ 0.125%) or interactions between the TTO and polystyrene. Similarly, adhesion to buccal epithelial and HeLa cells was also significantly reduced in the presence of 0.016-0.062% TTO. Treatment with 0.125% TTO, but not 0.062%, decreased the cell surface hydrophobicity of C. albicans, indicating one potential mechanism by which adhesion may be reduced. These data demonstrate that sub-inhibitory TTO reduces the adhesion of C. albicans to both human cells and polystyrene, inhibits biofilm formation and decreases cell surface hydrophobicity.
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Affiliation(s)
- Aurelia N Sudjana
- Discipline of Microbiology and Immunology (M502), School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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13
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Carson CF, Hammer KA, Southwell IA, Riley TV. [The side effects are exaggerated]. Lakartidningen 2012; 109:1419. [PMID: 23909012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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Thomsen PS, Jensen TM, Hammer KA, Carson CF, Mølgaard P, Riley TV. Survey of the Antimicrobial Activity of Commercially Available Australian Tea Tree (Melaleuca alternifolia) Essential Oil ProductsIn Vitro. J Altern Complement Med 2011; 17:835-41. [DOI: 10.1089/acm.2010.0508] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Per S. Thomsen
- School of Pharmacy, Murdoch University, Murdoch, Western Australia
| | - Theis M. Jensen
- School of Pharmacy, Murdoch University, Murdoch, Western Australia
| | - Kate A. Hammer
- Discipline of Microbiology and Immunology, School of Biomedical, Biomolecular, and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Christine F. Carson
- Discipline of Microbiology and Immunology, School of Biomedical, Biomolecular, and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Per Mølgaard
- School of Pharmacy, Murdoch University, Murdoch, Western Australia
| | - Thomas V. Riley
- Discipline of Microbiology and Immunology, School of Biomedical, Biomolecular, and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
- Divisions of Microbiology and Infectious Diseases, PathWest Laboratory Medicine WA, Nedlands, Australia
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Edmondson M, Newall N, Carville K, Smith J, Riley TV, Carson CF. Uncontrolled, open-label, pilot study of tea tree (Melaleuca alternifolia) oil solution in the decolonisation of methicillin-resistant Staphylococcus aureus positive wounds and its influence on wound healing. Int Wound J 2011; 8:375-84. [PMID: 21564552 DOI: 10.1111/j.1742-481x.2011.00801.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Many complementary and alternative products are used to treat wounds. The essential oil of Melaleuca alternifolia, tea tree oil, has proven antimicrobial and anti-inflammatory properties, may be useful in methicillin-resistant Staphylococcus aureus (MRSA) decolonisation regimens and is reputed to have 'wound-healing' properties, but more data are required to support these indications. The primary aim of this uncontrolled case series was to assess whether a tea tree oil solution used in a wound cleansing procedure could decolonise MRSA from acute and chronic wounds of mixed aetiology. The secondary aim was to determine if the tea tree oil solution influenced wound healing outcomes. Nineteen participants with wounds suspected of being colonised with MRSA were enrolled in a pilot study. Seven were subsequently shown not to have MRSA and were withdrawn from the study. As many as 11 of the remaining 12 participants were treated with a water-miscible tea tree oil (3·3%) solution applied as part of the wound cleansing regimen at each dressing change. Dressing changes were three times per week or daily as deemed necessary by the study nurse following assessment. One participant withdrew from the study before treatment. No participants were MRSA negative after treatment. After treatment had been implemented, 8 of the 11 treated wounds had begun to heal and reduced in size as measured by computer planimetry. Although this formulation and mode of delivery did not achieve the primary aim of the study, tea tree oil did not appear to inhibit healing and the majority of wounds reduced in size after treatment.
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Greay SJ, Ireland DJ, Kissick HT, Levy A, Beilharz MW, Riley TV, Carson CF. Induction of necrosis and cell cycle arrest in murine cancer cell lines by Melaleuca alternifolia (tea tree) oil and terpinen-4-ol. Cancer Chemother Pharmacol 2009; 65:877-88. [PMID: 19680653 DOI: 10.1007/s00280-009-1093-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 07/21/2009] [Indexed: 01/11/2023]
Abstract
PURPOSE To examine the in vitro anticancer activity of Melaleuca alternifolia (tea tree) oil (TTO), and its major active terpene component, terpinen-4-ol, against two aggressive murine tumour cell lines, AE17 mesothelioma and B16 melanoma. METHODS Effects of TTO and terpinen-4-ol on the cellular viability of two tumour cell lines and fibroblast cells were assessed by MTT assay. Induction of apoptotic and necrotic cell death was visualised by fluorescent microscopy and quantified by flow cytometry. Tumour cell ultrastructural changes were examined by transmission electron microscopy and changes in cell cycle distribution were assessed by flow cytometry, with changes in cellular morphology monitored by video time lapse microscopy. RESULTS TTO and terpinen-4-ol significantly inhibited the growth of two murine tumour cell lines in a dose- and time-dependent manner. Interestingly, cytotoxic doses of TTO and terpinen-4-ol were significantly less efficacious against non-tumour fibroblast cells. TTO and terpinen-4-ol induced necrotic cell death coupled with low level apoptotic cell death in both tumour cell lines. This primary necrosis was clarified by video time lapse microscopy and also by transmission electron microscopy which revealed ultrastructural features including cell and organelle swelling following treatment with TTO. In addition, both TTO and terpinen-4-ol induced their inhibitory effect by eliciting G1 cell cycle arrest. CONCLUSION TTO and terpinen-4-ol had significant anti-proliferative activity against two tumour cell lines. Moreover, the identification of primary necrotic cell death and cell cycle arrest of the aggressive tumour cells highlights the potential anticancer activity of TTO and terpinen-4-ol.
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Affiliation(s)
- S J Greay
- Discipline of Microbiology and Immunology (M502), School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
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Hammer KA, Carson CF, Dunstan JA, Hale J, Lehmann H, Robinson CJ, Prescott SL, Riley TV. Antimicrobial and anti-inflammatory activity of five Taxandria fragrans oils in vitro. Microbiol Immunol 2009; 52:522-30. [PMID: 19090831 DOI: 10.1111/j.1348-0421.2008.00070.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The antimicrobial activity of five samples of Taxandria fragrans essential oil was evaluated against a range of Gram-positive (n= 26) and Gram-negative bacteria (n= 39) and yeasts (n= 10). The majority of organisms were inhibited and/or killed at concentrations ranging from 0.06-4.0% v/v. Geometric means of MIC were lowest for oil Z (0.77% v/v), followed by oils X (0.86%), C (1.12%), A (1.23%) and B (1.24%). Despite differences in susceptibility data between oils, oils A and X did not differ when tested at 2% v/v in a time kill assay against Staphylococcus aureus. Cytotoxicity assays using peripheral blood mononuclear cells demonstrated that T. fragrans oil was cytotoxic at 0.004% v/v but not at 0.002%. Exposure to one or more of the oils at concentrations of <or=0.002% v/v resulted in a dose responsive reduction in the production of proinflammatory cytokines IL-6 and TNF-alpha, regulatory cytokine IL-10, Th1 cytokine IFN-gamma and Th2 cytokines IL-5 and IL-13 by PHA stimulated mononuclear cells. Oil B inhibited the production of all cytokines except IL-10, oil X inhibited TNF-alpha, IL-6 and IL-10, oil A inhibited TNF-alpha and IL-6, oil C inhibited IL-5 and IL-6 and oil Z inhibited IL-13 only. IL-6 production was significantly inhibited by the most oils (A, B, C and X), followed by TNF-alpha (oils A, B and X). In conclusion, T. fragrans oil showed both antimicrobial and anti-inflammatory activity in vitro, however, the clinical relevance of this remains to be determined.
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Affiliation(s)
- Katherine A Hammer
- Discipline of Microbiology and Immunology, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, WA, Australia.
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Hammer KA, Carson CF, Riley TV. Frequencies of resistance to Melaleuca alternifolia (tea tree) oil and rifampicin in Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. Int J Antimicrob Agents 2008; 32:170-3. [DOI: 10.1016/j.ijantimicag.2008.03.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Accepted: 03/20/2008] [Indexed: 10/21/2022]
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Carson CF, Smith DW, Lampacher GJ, Riley TV. Use of deception to achieve double-blinding in a clinical trial of Melaleuca alternifolia (tea tree) oil for the treatment of recurrent herpes labialis. Contemp Clin Trials 2008; 29:9-12. [PMID: 17544340 DOI: 10.1016/j.cct.2007.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 04/08/2007] [Accepted: 04/25/2007] [Indexed: 10/23/2022]
Abstract
Double-blinding is an important and widely implemented feature of clinical trials although its success is rarely assessed. In a randomized, placebo-controlled trial of tea tree oil, an aromatic essential oil, for the treatment of recurrent herpes labialis (RHL), or cold sores, deception was used to prevent volunteers from identifying their treatment allocation. Volunteers received placebo (n=102) or tea tree oil (n=112) ointment in preparation for their next episode of RHL and were told, falsely, that the aroma of the ointments had been changed to prevent identification of the treatment group. At the trial's end, of the volunteers who had used their ointment and presented for treatment assessment (n=100), approximately 50% correctly guessed their treatment allocation (P=0.774). Amongst volunteers that had not presented for treatment assessment (n=114), 12 volunteers did not provide blinding data and 46 did not open their tube. For the 56 volunteers who opened their tube, less than half of those receiving tea tree oil (44.4%) and only a small proportion of those on placebo (17.2%) were able to correctly identify their treatment allocation. Among the volunteers that were not treated, the P-value was 0.083. This study showed that the ethical use of deception may provide effective blinding in challenging circumstances.
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Affiliation(s)
- Christine F Carson
- Microbiology and Immunology Discipline, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Australia.
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Papadopoulos CJ, Carson CF, Hammer KA, Riley TV. Susceptibility of pseudomonads to Melaleuca alternifolia (tea tree) oil and components. J Antimicrob Chemother 2006; 58:449-51. [PMID: 16735435 DOI: 10.1093/jac/dkl200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Thirty isolates of Pseudomonas aeruginosa, 15 isolates of Pseudomonas putida and 11 isolates of Pseudomonas fluorescens were tested for susceptibility to tea tree oil (TTO), the essential oil of Melaleuca alternifolia, and the components terpinen-4-ol, alpha-terpineol, cineole, gamma-terpinene and rho-cymene. METHODS MICs were determined by broth microdilution in Mueller-Hinton medium supplemented with 0.002% (v/v) Tween 80. RESULTS The MIC90 of TTO for all isolates tested was 4% (v/v) or less. Susceptibility to components tested varied between species. CONCLUSIONS Pseudomonas spp. are susceptible to TTO and some of its components although they are less susceptible than many other bacteria tested previously.
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Affiliation(s)
- Chelsea J Papadopoulos
- Microbiology and Immunology Discipline, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
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Hammer KA, Carson CF, Riley TV, Nielsen JB. A review of the toxicity of Melaleuca alternifolia (tea tree) oil. Food Chem Toxicol 2006; 44:616-25. [PMID: 16243420 DOI: 10.1016/j.fct.2005.09.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 08/30/2005] [Accepted: 09/01/2005] [Indexed: 11/18/2022]
Abstract
The essential oil of Melaleuca alternifolia, also known as tea tree or melaleuca oil, is widely available and has been investigated as an alternative antimicrobial, anti-inflammatory and anti-cancer agent. While these properties are increasingly well characterised, relatively limited data are available on the safety and toxicity of the oil. Anecdotal evidence from almost 80 years of use suggests that the topical use of the oil is relatively safe, and that adverse events are minor, self-limiting and occasional. Published data indicate that TTO is toxic if ingested in higher doses and can also cause skin irritation at higher concentrations. Allergic reactions to TTO occur in predisposed individuals and may be due to the various oxidation products that are formed by exposure of the oil to light and/or air. Adverse reactions may be minimised by avoiding ingestion, applying only diluted oil topically and using oil that has been stored correctly. Data from individual components suggest that TTO has the potential to be developmentally toxic if ingested at higher doses, however, TTO and its components are not genotoxic. The limited ecotoxicity data available indicate that TTO is toxic to some insect species but more studies are required.
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Affiliation(s)
- K A Hammer
- Microbiology and Immunology (M502), School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia.
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Abstract
Complementary and alternative medicines such as tea tree (melaleuca) oil have become increasingly popular in recent decades. This essential oil has been used for almost 100 years in Australia but is now available worldwide both as neat oil and as an active component in an array of products. The primary uses of tea tree oil have historically capitalized on the antiseptic and anti-inflammatory actions of the oil. This review summarizes recent developments in our understanding of the antimicrobial and anti-inflammatory activities of the oil and its components, as well as clinical efficacy. Specific mechanisms of antimicrobial and anti-inflammatory action are reviewed, and the toxicity of the oil is briefly discussed.
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Affiliation(s)
- C F Carson
- Microbiology and Immunology (M502), School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
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Messager S, Hammer KA, Carson CF, Riley TV. Effectiveness of hand-cleansing formulations containing tea tree oil assessed ex vivo on human skin and in vivo with volunteers using European standard EN 1499. J Hosp Infect 2005; 59:220-8. [PMID: 15694979 DOI: 10.1016/j.jhin.2004.06.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Accepted: 06/06/2004] [Indexed: 11/18/2022]
Abstract
The efficacy of formulations containing tea tree oil (TTO) has been assessed in vitro in previous studies. Products that passed the European suspension test guidelines were investigated further in this study, in vivo with volunteers using the European handwashing method (EN 1499) and ex vivo using freshly excised human skin samples. The activity of 5% TTO in 0.001% Tween 80, in a hygienic skin wash (HSW) and in an alcoholic hygienic skin wash (AHSW) was investigated and compared with that of a non-medicated soft soap (SS, control). These formulations were assessed against Escherichia coli K12 as recommended by the European standard. In-vivo results showed that 5% TTO in Tween 80 and the AHSW were significantly more active than the SS after 1 min of handwashing. When assessed ex vivo, these two products were also significantly more active than the reference soap after 1 min of rubbing. Both methods showed that 5% TTO in Tween 80 was generally, although not always, more active than a handwash formulation, and that the AHSW was generally more active than the HSW, although this difference was not significant. The formulations tested, as well as the SS, were more active when assessed in vivo than ex-vivo against E. coli, although only the SS and the HSW were significantly more active in vivo. There appeared to be a pattern in the comparison between ex vivo and in vivo results. The antiseptics tested were, on average, 1.28+/-0.06 times more active when assessed in-vivo than when assessed ex vivo. Nevertheless, the main outcome of the European handwashing method is for the formulation tested to be significantly more active than the SS; both 5% TTO in Tween 80 and the AHSW achieved this both in-vivo and ex-vivo. TTO in Tween 80 and in formulations met the European in-vivo method requirements.
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Affiliation(s)
- S Messager
- Discipline of Microbiology, School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
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Messager S, Hammer KA, Carson CF, Riley TV. Assessment of the antibacterial activity of tea tree oil using the European EN 1276 and EN 12054 standard suspension tests. J Hosp Infect 2005; 59:113-25. [PMID: 15620445 DOI: 10.1016/j.jhin.2004.07.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Accepted: 05/28/2004] [Indexed: 11/22/2022]
Abstract
The activity of tea tree oil (TTO) and TTO-containing products was investigated according to the EN 1276 and EN 12054 European suspension methods. The activity of different concentrations of TTO, a hygienic skin wash (HSW), an alcoholic hygienic skin wash (AHSW) and an alcoholic hand rub (AHR) was investigated. These formulations were assessed in perfect conditions with the EN 12054 test, and in perfect conditions as well as in the presence of interfering substances with the EN 1276 test, against Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli and Pseudomonas aeruginosa. With the latter test, the activity of the same formulations without TTO was also assessed as a control. With the EN 1276 test, the AHR achieved a >10(5)-fold reduction against all four test organisms within a 1-min contact time. The AHSW achieved a >or=10(5)-fold reduction against A. baumannii after a 1-min contact time and against S. aureus, E. coli and P. aeruginosa after a 5-min contact time. The efficacy of TTO appeared to be dependent on the formulation and the concentration tested, the concentration of interfering substances and, lastly, the organism tested. Nevertheless, 5% TTO achieved a >10(4)-fold reduction in P. aeruginosa cell numbers after a 5-min contact time in perfect conditions. TTO (5%) in 0.001% Tween 80 was significantly more active against E. coli and P. aeruginosa than against S. aureus and A. baumannii. With the EN 12054 test, after a 1-min contact time, 5% TTO in 0.001% Tween 80 and the AHSW achieved a >10(4)-fold reduction in E. coli and A. baumannii cell numbers, respectively, and the AHR achieved a >4 log10 reduction against all organisms tested. The formulations used in this study are now being tested using a novel ex vivo method as well as the in vivo European standard handwashing method EN 1499.
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Affiliation(s)
- S Messager
- Discipline of Microbiology, School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
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Longbottom CJ, Carson CF, Hammer KA, Mee BJ, Riley TV. Tolerance of Pseudomonas aeruginosa to Melaleuca alternifolia (tea tree) oil is associated with the outer membrane and energy-dependent cellular processes. J Antimicrob Chemother 2004; 54:386-92. [PMID: 15254026 DOI: 10.1093/jac/dkh359] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The essential oil of Melaleuca alternifolia (tea tree oil) and its components have antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria, fungi and viruses. The mechanism(s) by which Pseudomonas aeruginosa NCTC 10662 maintains a decreased susceptibility to tea tree oil and components was investigated. RESULTS Ethylene diamine tetraacetic acid enhanced the antimicrobial activity of tea tree oil and terpinen-4-ol against stationary phase P. aeruginosa while polymyxin B nonapeptide enhanced the activity of tea tree oil and gamma-terpinene. Pre-treatment with the protonophore carbonyl cyanide m-chlorophenylhydrazone increased the susceptibility of exponential phase cells to sub-inhibitory concentrations of tea tree oil, terpinen-4-ol and gamma-terpinene, indicating that intrinsic tolerance to tea tree oil and components is substantially energy dependent. CONCLUSIONS Increased tolerance to tea tree oil in P. aeruginosa is directly related to the barrier and energy functions of the outer membrane, and may involve efflux systems.
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Affiliation(s)
- Chelsea J Longbottom
- Microbiology Discipline (M502), School of Biomedical and Chemical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009.
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Hammer KA, Carson CF, Riley TV. Antifungal effects of Melaleuca alternifolia (tea tree) oil and its components on Candida albicans, Candida glabrata and Saccharomyces cerevisiae. J Antimicrob Chemother 2004; 53:1081-5. [PMID: 15140856 DOI: 10.1093/jac/dkh243] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate the mechanism of action of tea tree oil and its components against Candida albicans, Candida glabrata and Saccharomyces cerevisiae. METHODS Yeast cells were treated with tea tree oil or components, at one or more concentrations, for up to 6 h. During this time, alterations in permeability were assessed by measuring the leakage of 260 nm absorbing materials and by the uptake of Methylene Blue dye. Membrane fluidity was measured by 1,6-diphenyl-1,3,5-hexatriene fluorescence. The effects of tea tree oil on glucose-induced medium acidification were quantified by measuring the pH of cell suspensions in the presence of both tea tree oil and glucose. RESULTS The treatment of C. albicans with tea tree oil and components at concentrations of between 0.25 and 1.0% (v/v) altered both permeability and membrane fluidity. Membrane fluidity was also increased when C. albicans was cultured for 24 h with 0.016%-0.06% (v/v) tea tree oil, as compared with control cells. For all three organisms, glucose-induced acidification of the external medium was inhibited in a dose-dependent manner in the presence of 0.2%, 0.3% and 0.4% tea tree oil. CONCLUSIONS Data from this study support the hypothesis that tea tree oil and components exert their antifungal actions by altering membrane properties and compromising membrane-associated functions.
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Affiliation(s)
- K A Hammer
- Microbiology Discipline, School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley.
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Carson CF, Riley TV. Non-antibiotic therapies for infectious diseases. Commun Dis Intell Q Rep 2004; 27 Suppl:S143-6. [PMID: 12807291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
The emergence of multiple antibiotic resistant organisms in the general community is a potentially serious threat to public health. The emergence of antibiotic resistance has not yet prompted a radical revision of antibiotic utilisation. Instead it has prompted the development of additional antibiotics. Unfortunately, this does not relieve the underlying selection pressure that drives the development of resistance. A paradigm shift in the treatment of infectious disease is necessary to prevent antibiotics becoming obsolete and, where appropriate, alternatives to antibiotics ought to be considered. There are already several non-antibiotic approaches to the treatment and prevention of infection including probiotics, phages and phytomedicines. There is some evidence that probiotics such as Lactobacillus spp. or Saccharomyces boulardii are useful in the prevention and treatment of diarrhoea, including Clostridium difficile-associated diarrhoea that can be difficult to treat and recurs frequently. Bacteriophages have received renewed attention for the control of both staphylococcal and gastrointestinal infections. Phytomedicines that have been utilised in the treatment of infections include artesunate for malaria, tea tree oil for skin infections, honey for wound infections, mastic gum for Helicobacter pylori gastric ulcers and cranberry juice for urinary tract infections. Many infections may prove amenable to safe and effective treatment with non-antibiotics.
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Affiliation(s)
- Christine F Carson
- Department of Microbiology, The University of Western Australia, Crawley, Western Australia
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Abstract
The in vitro activity of Melaleuca alternifolia (tea tree) oil against 161 isolates of oral bacteria from 15 genera was determined. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) ranged from 0.003 to 2.0% (v/v). MIC90 values were 1.0% (v/v) for Actinomyces spp., Lactobacillus spp., Streptococcus mitis and Streptococcus sanguis, and 0.1% (v/v) for Prevotella spp. Isolates of Porphyromonas, Prevotella and Veillonella had the lowest MICs and MBCs, and isolates of Streptococcus, Fusobacterium and Lactobacillus had the highest. Time kill studies with Streptococcus mutans and Lactobacillus rhamnosus showed that treatment with > or = 0.5% tea tree oil caused decreases in viability of >3 log colony forming units/ml after only 30 s, and viable organisms were not detected after 5 min. These studies indicate that a range of oral bacteria are susceptible to tea tree oil, suggesting that tea tree oil may be of use in oral healthcare products and in the maintenance of oral hygiene.
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Affiliation(s)
- K A Hammer
- Discipline of Microbiology, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia.
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Abstract
AIMS To investigate the in vitro antifungal activity of the components of Melaleuca alternifolia (tea tree) oil. METHODS AND RESULTS Activity was investigated by broth microdilution and macrodilution, and time kill methods. Components showing the most activity, with minimum inhibitory concentrations and minimum fungicidal concentrations of < or =0.25%, were terpinen-4-ol, alpha-terpineol, linalool, alpha-pinene and beta-pinene, followed by 1,8-cineole. The remaining components showed slightly less activity and had values ranging from 0.5 to 2%, with the exception of beta-myrcene which showed no detectable activity. Susceptibility data generated for several of the least water-soluble components were two or more dilutions lower by macrodilution, compared with microdilution. CONCLUSIONS All tea tree oil components, except beta-myrcene, had antifungal activity. The lack of activity reported for some components by microdilution may be due to these components becoming absorbed into the polystyrene of the microtitre tray. This indicates that plastics are unsuitable as assay vessels for tests with these or similar components. SIGNIFICANCE AND IMPACT OF THE STUDY This study has identified that most components of tea tree oil have activity against a range of fungi. However, the measurement of antifungal activity may be significantly influenced by the test method.
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Affiliation(s)
- K A Hammer
- Discipline of Microbiology, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley, WA, Australia.
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Hammer KA, Carson CF, Riley TV. In vitro activity of Melaleuca alternifolia (tea tree) oil against dermatophytes and other filamentous fungi. J Antimicrob Chemother 2002; 50:195-9. [PMID: 12161399 DOI: 10.1093/jac/dkf112] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The in vitro activity of Melaleuca alternifolia (tea tree) oil against dermatophytes (n = 106) and filamentous fungi (n = 78) was determined. Tea tree oil MICs for all fungi ranged from 0.004% to 0.25% and minimum fungicidal concentrations (MFCs) ranged from <0.03% to 8.0%. Time-kill experiments with 1-4 x MFC demonstrated that three of the four test organisms were still detected after 8 h of treatment, but not after 24 h. Comparison of the susceptibility to tea tree oil of germinated and non-germinated Aspergillus niger conidia showed germinated conidia to be more susceptible than non-germinated conidia. These data demonstrate that tea tree oil has both inhibitory and fungicidal activity.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia.
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Carson CF, Mee BJ, Riley TV. Mechanism of action of Melaleuca alternifolia (tea tree) oil on Staphylococcus aureus determined by time-kill, lysis, leakage, and salt tolerance assays and electron microscopy. Antimicrob Agents Chemother 2002; 46:1914-20. [PMID: 12019108 PMCID: PMC127210 DOI: 10.1128/aac.46.6.1914-1920.2002] [Citation(s) in RCA: 508] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The essential oil of Melaleuca alternifolia (tea tree) has broad-spectrum antimicrobial activity. The mechanisms of action of tea tree oil and three of its components, 1,8-cineole, terpinen-4-ol, and alpha-terpineol, against Staphylococcus aureus ATCC 9144 were investigated. Treatment with these agents at their MICs and two times their MICs, particularly treatment with terpinen-4-ol and alpha-terpineol, reduced the viability of S. aureus. None of the agents caused lysis, as determined by measurement of the optical density at 620 nm, although cells became disproportionately sensitive to subsequent autolysis. Loss of 260-nm-absorbing material occurred after treatment with concentrations equivalent to the MIC, particularly after treatment with 1,8-cineole and alpha-terpineol. S. aureus organisms treated with tea tree oil or its components at the MIC or two times the MIC showed a significant loss of tolerance to NaCl. When the agents were tested at one-half the MIC, only 1,8-cineole significantly reduced the tolerance of S. aureus to NaCl. Electron microscopy of terpinen-4-ol-treated cells showed the formation of mesosomes and the loss of cytoplasmic contents. The predisposition to lysis, the loss of 260-nm-absorbing material, the loss of tolerance to NaCl, and the altered morphology seen by electron microscopy all suggest that tea tree oil and its components compromise the cytoplasmic membrane.
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Affiliation(s)
- Christine F Carson
- Department of Microbiology, The University of Western Australia, Crawley.
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Carson CF, Ashton L, Dry L, Smith DW, Riley TV. Melaleuca alternifolia (tea tree) oil gel (6%) for the treatment of recurrent herpes labialis. J Antimicrob Chemother 2001; 48:450-1. [PMID: 11533019 DOI: 10.1093/jac/48.3.450] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
The identity, sources and composition of tea tree (Melaleuca alternifolia) oil are discussed, and earlier errors in the literature indicated. Reports of both therapeutic and allergenic effects are reviewed.
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Affiliation(s)
- C F Carson
- Department of Microbiology, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands WA 6009, Australia.
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Brand C, Ferrante A, Prager RH, Riley TV, Carson CF, Finlay-Jones JJ, Hart PH. The water-soluble components of the essential oil of Melaleuca alternifolia (tea tree oil) suppress the production of superoxide by human monocytes, but not neutrophils, activated in vitro. Inflamm Res 2001; 50:213-9. [PMID: 11392609 DOI: 10.1007/s000110050746] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVE To evaluate the regulatory properties of the essential oil of Melaleuca alternifolia (tea tree oil) on the production of oxygen derived reactive species by human peripheral blood leukocytes activated in vitro. MATERIALS AND METHODS The ability of tea tree oil to reduce superoxide production by neutrophils and monocytes stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP), lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA) was examined. RESULTS The water-soluble fraction of tea tree oil had no significant effect on agonist-stimulated superoxide production by neutrophils, but significantly and dose-dependently suppressed agonist-stimulated superoxide production by monocytes. This suppression was not due to cell death. Chemical analysis identified the water-soluble components to be terpinen-4-ol, alpha-terpineol and 1,8-cineole. When examined individually, terpinen-4-ol significantly suppressed fMLP- and LPS- but not PMA-stimulated superoxide production; alpha-terpineol significantly suppressed fMLP-, LPS- and PMA-stimulated superoxide production; 1,8-cineole was without effect. CONCLUSION Tea tree oil components suppress the production of superoxide by monocytes, but not neutrophils, suggesting the potential for selective regulation of cell types by these components during inflammation.
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Affiliation(s)
- C Brand
- Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, Australia
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Caelli M, Porteous J, Carson CF, Heller R, Riley TV. Tea tree oil as an alternative topical decolonization agent for methicillin-resistant Staphylococcus aureus. J Hosp Infect 2000; 46:236-7. [PMID: 11073734 DOI: 10.1053/jhin.2000.0830] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The combination of a 4% tea tree oil nasal ointment and 5% tea tree oil body wash was compared with a standard 2% mupirocin nasal ointment and triclosan body wash for the eradication of methicillin-resistant Staphylococcus aureus carriage. The tea tree oil combination appeared to perform better than the standard combination, although the difference was not statistically significant due to the small number of patients.
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Affiliation(s)
- M Caelli
- Department of Clinical Epidemiology, University of Newcastle, Callaghan, NSW, Australia
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Hart PH, Brand C, Carson CF, Riley TV, Prager RH, Finlay-Jones JJ. Terpinen-4-ol, the main component of the essential oil of Melaleuca alternifolia (tea tree oil), suppresses inflammatory mediator production by activated human monocytes. Inflamm Res 2000; 49:619-26. [PMID: 11131302 DOI: 10.1007/s000110050639] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVE AND DESIGN To evaluate potential antiinflammatory properties of tea tree oil, the essential oil steam distilled from the Australian native plant, Melaleuca alternifolia. MATERIAL AND METHODS The ability of tea tree oil to reduce the production in vitro of tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-8, IL-10 and prostaglandin E2 (PGE2) by lipopolysaccharide (LPS)-activated human peripheral blood monocytes was examined. RESULTS Tea tree oil emulsified by sonication in a glass tube into culture medium containing 10% fetal calf serum (FCS) was toxic for monocytes at a concentration of 0.016% v/v. However, the water soluble components of tea tree oil at concentrations equivalent to 0.125% significantly suppressed LPS-induced production of TNFalpha, IL-1beta and IL-10 (by approximately 50%) and PGE2 (by approximately 30%) after 40 h. Gas chromatography/mass spectrometry identified terpinen-4-ol (42 %), a-terpineol (3 %) and 1,8-cineole (2%, respectively, of tea tree oil) as the water soluble components of tea tree oil. When these components were examined individually, only terpinen-4-ol suppressed the production after 40 h of TNFalpha, IL-1beta, IL-8, IL-10 and PGE2 by LPS-activated monocytes. CONCLUSION The water-soluble components of tea tree oil can suppress pro-inflammatory mediator production by activated human monocytes.
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Affiliation(s)
- P H Hart
- Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University, Adelaide, Australia.
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Hammer KA, Carson CF, Riley TV. Melaleuca alternifolia (tea tree) oil inhibits germ tube formation by Candida albicans. Med Mycol 2000; 38:355-62. [PMID: 11092382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The effect of tea tree oil (TTO) on the formation of germ tubes by Candida albicans was examined. Two isolates were tested for germ tube formation (GTF) in the presence of TTO concentrations (% v/v) ranging from 0.25% (1/2 minimum inhibitory concentration [MIC]) to 0.004% (1/128 MIC). GTF at 4 h in the presence of 0.004 and 0.008% (both isolates) and 0.016% (one isolate) TTO did not differ significantly (P > 0.05) from controls. At all other concentrations at 4 h, GTF differed significantly from controls (P < 0.01). A further eight isolates were tested for GTF in the presence of 0.031% TTO, and at 4h the mean GTF for all 10 isolates ranged 10.0-68.5%. Two isolates were examined for their ability to form germ tubes after 1 h of pre-exposure to several concentrations of TTO, prior to induction of germ tubes in horse serum. Cells pre-exposed to 0.125 and 0.25% TTO formed significantly fewer germ tubes than control cells at 1 h (P < 0.05), but only those cells pre-exposed to 0.25% differed significantly from control cells at later time points (P < 0.01). GTF by C. albicans is affected by the presence of, or pre-exposure to, sub-inhibitory concentrations of TTO. This may have therapeutic implications.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands.
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Abstract
There are limited reports of the prevalence of positive reactions in healthy adults to patch tests with standard allergens; there are no recent comprehensive studies from Australia. Healthy adult volunteers (n = 219) from the Western Australian community were patch tested using the European standard series of allergens. Seventy-seven (35%) reacted to at least one allergen, positive patch tests being most prevalent to nickel sulfate (20%), potassium dichromate (9%), cobalt chloride (6%) and fragrance mix (4%). Prevalence of positive patch tests to nickel and chromate was higher than that reported for another healthy population, which may stem from self-selection of volunteers or geographical differences, including extent of exposure to allergens.
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Affiliation(s)
- J E Greig
- Department of Microbiology, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Australia.
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Hammer KA, Carson CF, Riley TV. In vitro activities of ketoconazole, econazole, miconazole, and Melaleuca alternifolia (tea tree) oil against Malassezia species. Antimicrob Agents Chemother 2000; 44:467-9. [PMID: 10639388 PMCID: PMC89709 DOI: 10.1128/aac.44.2.467-469.2000] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The in vitro activities of ketoconazole, econazole, miconazole, and tea tree oil against 54 Malassezia isolates were determined by agar and broth dilution methods. Ketoconazole was more active than both econazole and miconazole, which showed very similar activities. M. furfur was the least susceptible species. M. sympodialis, M. slooffiae, M. globosa, and M. obtusa showed similar susceptibilities to the four agents.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, The University of Western Australia, Nedlands, Australia.
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Affiliation(s)
- J E Greig
- Department of Microbiology, The University of Western Australia, Nedlands, Australia
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Abstract
The antimicrobial activity of plant oils and extracts has been recognized for many years. However, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. In the present study, 52 plant oils and extracts were investigated for activity against Acinetobacter baumanii, Aeromonas veronii biogroup sobria, Candida albicans, Enterococcus faecalis, Escherichia col, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype typhimurium, Serratia marcescens and Staphylococcus aureus, using an agar dilution method. Lemongrass, oregano and bay inhibited all organisms at concentrations of < or = 2.0% (v/v). Six oils did not inhibit any organisms at the highest concentration, which was 2.0% (v/v) oil for apricot kernel, evening primrose, macadamia, pumpkin, sage and sweet almond. Variable activity was recorded for the remaining oils. Twenty of the plant oils and extracts were investigated, using a broth microdilution method, for activity against C. albicans, Staph. aureus and E. coli. The lowest minimum inhibitory concentrations were 0.03% (v/v) thyme oil against C. albicans and E. coli and 0.008% (v/v) vetiver oil against Staph. aureus. These results support the notion that plant essential oils and extracts may have a role as pharmaceuticals and preservatives.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, The University of Western Australia, Nedlands, Western Australia.
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Hammer KA, Carson CF, Riley TV. Influence of organic matter, cations and surfactants on the antimicrobial activity of Melaleuca alternifolia (tea tree) oil in vitro. J Appl Microbiol 1999; 86:446-52. [PMID: 10196749 DOI: 10.1046/j.1365-2672.1999.00684.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of some potentially interfering substances and conditions on the antimicrobial activity of Melaleuca alternifolia (tea tree) oil was investigated. Agar and broth dilution methods were used to determine minimum inhibitory and cidal concentrations of tea tree oil in the presence and absence of each potentially interfering substance. Activity was determined against Gram-positive and -negative bacteria, and Candida albicans. Minimum inhibitory or cidal concentrations differed from controls by two or more dilutions, for one or more organisms, where Tween-20, Tween-80, skim-milk powder and bovine serum albumin were assessed. These differences were not seen when assays were performed in anaerobic conditions, or in the presence of calcium and magnesium ions. The effect of organic matter on the antimicrobial activity of tea tree oil was also investigated by an organic soil neutralization test. Organisms were exposed to lethal concentrations of tea tree oil ranging from 1-10% (v/v), in the presence of 1-30% (w/v) dry bakers' yeast. After 10 min contact time, viability was determined. At > or = 1%, organic matter compromised the activity of each concentration of tea tree oil against Staphylococcus aureus and C. albicans. At 10% or more, organic matter compromised the activity of each tea tree oil concentration against Pseudomonas aeruginosa. Organic matter affected 1 and 2% tea tree oil, but not 4 and 8%, against Escherichia coli. In conclusion, organic matter and surfactants compromise the antimicrobial activity of tea tree oil, although these effects vary between organisms.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, University of Western Australia, Nedlands, Western Australia.
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Hammer KA, Carson CF, Riley TV. In vitro susceptibilities of lactobacilli and organisms associated with bacterial vaginosis to Melaleuca alternifolia (tea tree) oil. Antimicrob Agents Chemother 1999; 43:196. [PMID: 10094671 PMCID: PMC89050 DOI: 10.1128/aac.43.1.196] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Hammer KA, Carson CF, Riley TV. In-vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products, against Candida spp. J Antimicrob Chemother 1998; 42:591-5. [PMID: 9848442 DOI: 10.1093/jac/42.5.591] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The in-vitro activity of a range of essential oils, including tea tree oil, against the yeast candida was examined. Of the 24 essential oils tested by the agar dilution method against Candida albicans ATCC 10231, three did not inhibit C. albicans at the highest concentration tested, which was 2.0% (v/v) oil. Sandalwood oil had the lowest MIC, inhibiting C. albicans at 0.06%. Melaleuca alternifolia (tea tree) oil was investigated for activity against 81 C. albicans isolates and 33 non-albicans Candida isolates. By the broth microdilution method, the minimum concentration of oil inhibiting 90% of isolates for both C. albicans and non-albicans Candida species was 0.25% (v/v). The minimum concentration of oil killing 90% of isolates was 0.25% for C. albicans and 0.5% for non-albicans Candida species. Fifty-seven Candida isolates were tested for sensitivity to tea tree oil by the agar dilution method; the minimum concentration of oil inhibiting 90% of isolates was 0.5%. Tests on three intra-vaginal tea tree oil products showed these products to have MICs and minimum fungicidal concentrations comparable to those of non-formulated tea tree oil, indicating that the tea tree oil contained in these products has retained its anticandidal activity. These data indicate that some essential oils are active against Candida spp., suggesting that they may be useful in the topical treatment of superficial candida infections.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, The University of Western Australia, The Queen Elizabeth II Medical Centre, Nedlands
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Affiliation(s)
- C F Carson
- Department of Microbiology, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Australia.
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Hammer KA, Carson CF, Riley TV. In vitro susceptibility of Malassezia furfur to the essential oil of Melaleuca alternifolia. J Med Vet Mycol 1997; 35:375-7. [PMID: 9402533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The susceptibility of 64 Malassezia furfur isolates to Melaleuca alternifolia oil was determined. The minimum inhibitory concentration for 90% of isolates was 0.25% by agar dilution and 0.12% by broth dilution. These data indicate that tea tree oil may be useful in the treatment of skin conditions involving M. furfur.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, University of Western Australia, Nedlands.
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Hammer KA, Carson CF, Riley TV. Susceptibility of transient and commensal skin flora to the essential oil of Melaleuca alternifolia (tea tree oil). Am J Infect Control 1996; 24:186-9. [PMID: 8806995 DOI: 10.1016/s0196-6553(96)90011-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The purpose of this study was to determine the susceptibility of a range of transient and commensal skin flora to the essential oil of Melaleuca alternifolia, or tea tree. METHODS A modified broth microdilution method was used. Polyoxyethylene sorbitan mono-oleate detergent was added to the test medium to enhance solubility of the tea tree oil. RESULTS Serratia marcescens had the lowest minimum inhibitory concentration (MIC90) of 0.25%. The highest MIC90 was 3% for Pseudomonas aeruginosa. The lowest minimum bactericidal concentration (MBC90) was 0.25% for S. marcescens and Klebsiella pneumoniae, whereas the highest was 8% for Staphylococcus capitis. CONCLUSIONS S. aureus and most of the gram-negative bacteria tested were more susceptible to tea tree oil than the coagulase-negative staphylococci and micrococci. These results suggest that tea tree oil may be useful in removing transient skin flora while suppressing but maintaining resident flora.
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Affiliation(s)
- K A Hammer
- Department of Microbiology, University of Western Australia
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Carson CF, Hammer KA, Riley TV. In-vitro activity of the essential oil of Melaleuca alternifolia against Streptococcus spp. J Antimicrob Chemother 1996; 37:1177-8. [PMID: 8836821 DOI: 10.1093/jac/37.6.1177] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Abstract
Tea tree oil, or the essential oil of Melaleuca alternifolia, is becoming increasingly popular as a naturally occurring antimicrobial agent. The antimicrobial activity of eight components of tea tree oil was evaluated using disc diffusion and broth microdilution methods. Attempts were also made to overcome methodological problems encountered with testing compounds which have limited solubility in aqueous media. After assessing media with and without solubilizing agents, the disc diffusion method was used to determine the susceptibility of a range of micro-organisms to 1,8-cineole, 1-terpinen-4-ol, rho-cymene, linalool, alpha-terpinene, gamma-terpinene, alpha-terpineol and terpinolene. While the disc diffusion method lacked reproducibility, it was considered useful as a procedure for screening for antimicrobial activity. Terpinen-4-ol was active against all the test organisms while rho-cymene demonstrated no antimicrobial activity. Linalool and alpha-terpineol were active against all organisms with the exception of Pseudomonas aeruginosa. Minimum inhibitory and minimum cidal concentrations of each component against Candida albicans, Escherichia coli and Staphylococcus aureus were determined using a broth microdilution method. Modifications to this method overcame solubility and turbidity problems associated with the oil components and allowed the antimicrobial activity of each of the components to be quantified reproducibly. There was reasonable agreement between minimum inhibitory concentrations and zones of inhibition. These results may have significant implications for the future development of tea tree oil as an antimicrobial agent.
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Affiliation(s)
- C F Carson
- Department of Microbiology, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands
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Carson CF, Cookson BD, Farrelly HD, Riley TV. Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil of Melaleuca alternifolia. J Antimicrob Chemother 1995; 35:421-4. [PMID: 7782258 DOI: 10.1093/jac/35.3.421] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
All 66 isolates of Staphylococcus aureus tested were susceptible to the essential oil of Melaleuca alternifolia, or tea tree oil, in disc diffusion and modified broth microdilution methods. Of the isolates tested, 64 were methicillin-resistant S. aureus (MRSA) and 33 were mupirocin-resistant. The MIC and MBC for 60 Australian isolates were 0.25% and 0.50%, respectively. Comparable results were obtained by co-workers in Britain using similar methods. These in-vitro results suggest tea tree oil may be useful in the treatment of MRSA carriage.
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Affiliation(s)
- C F Carson
- Department of Microbiology, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands
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