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Vehusheia SLK, Roman CI, Arnoldini M, Hierold C. Experimental In Vitro Microfluidic Calorimetric Chip Data towards the Early Detection of Infection on Implant Surfaces. SENSORS (BASEL, SWITZERLAND) 2024; 24:1019. [PMID: 38339736 PMCID: PMC10857106 DOI: 10.3390/s24031019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
Heat flux measurement shows potential for the early detection of infectious growth. Our research is motivated by the possibility of using heat flux sensors for the early detection of infection on aortic vascular grafts by measuring the onset of bacterial growth. Applying heat flux measurement as an infectious marker on implant surfaces is yet to be experimentally explored. We have previously shown the measurement of the exponential growth curve of a bacterial population in a thermally stabilized laboratory environment. In this work, we further explore the limits of the microcalorimetric measurements via heat flux sensors in a microfluidic chip in a thermally fluctuating environment.
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Affiliation(s)
- Signe L. K. Vehusheia
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; (C.I.R.); (C.H.)
| | - Cosmin I. Roman
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; (C.I.R.); (C.H.)
| | - Markus Arnoldini
- Department of Health Sciences and Technology, ETH Zurich, 8093 Zurich, Switzerland;
| | - Christofer Hierold
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; (C.I.R.); (C.H.)
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2
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Cichos KH, Ruark RJ, Ghanem ES. Isothermal microcalorimetry improves accuracy and time to bacterial detection of periprosthetic joint infection after total joint arthroplasty. J Clin Microbiol 2023; 61:e0089323. [PMID: 37947408 PMCID: PMC10729692 DOI: 10.1128/jcm.00893-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023] Open
Abstract
Isothermal microcalorimetry (IMC) was evaluated compared to conventional cultures to determine the clinical performance for diagnosing periprosthetic joint infection (PJI) of hip/knee replacements. We prospectively collected three to five deep tissue samples per patient from 152 patients undergoing conversion or revision hip/knee arthroplasty from July 2020 to November 2022. Cultures and IMC for each sample were compared for concordance, median time to detection (TTD), and diagnostic performance based on 2013 Musculoskeletal Infection Society criteria. Secondary analyses involved patients on antibiotics at sampling. The 152 total patients had 592 tissue samples (mean 3.9 ± 0.3) with sample concordance between cultures and IMC of 90%. IMC demonstrated a sensitivity of 83%, specificity of 100%, negative predictive value (NPV) of 89%, and positive predictive value (PPV) of 100% for PJI. Cultures resulted in 69% sensitivity, 100% specificity, 81% NPV, and 100% PPV. The accuracy of IMC was 93% compared to 87% for cultures (P < 0.001). The median TTD of PJI by cultures was 51 (21-410) hours compared to 10 (0.5-148) hours for IMC (P < 0.001). For 39 patients on chronic antibiotics, sensitivity in PJI detection was 93%, specificity 100%, NPV 85%, and PPV 100% by IMC compared to 79% sensitivity, 100% specificity, 65% NPV, and 100% PPV for cultures. The accuracy was 95% for IMC compared to 85% for cultures (P < 0.001) with median TTD of 12 (0.5-127) hours compared to 52 (21-174) hours (P < 0.001). Utilizing IMC for PJI detection improves TTD by nearly 2 days while improving diagnostic accuracy compared to cultures, particularly in patients on chronic antibiotics.
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Affiliation(s)
- Kyle H. Cichos
- Department of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Hughston Foundation, Columbus, Georgia, USA
- Hughston Clinic, Columbus, Georgia, USA
| | | | - Elie S. Ghanem
- Department of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri, USA
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3
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Vehusheia SLK, Roman C, Braissant O, Arnoldini M, Hierold C. Enabling direct microcalorimetric measurement of metabolic activity and exothermic reactions onto microfluidic platforms via heat flux sensor integration. MICROSYSTEMS & NANOENGINEERING 2023; 9:56. [PMID: 37180454 PMCID: PMC10169645 DOI: 10.1038/s41378-023-00525-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 02/13/2023] [Indexed: 05/16/2023]
Abstract
All biological processes use or produce heat. Traditional microcalorimeters have been utilized to study the metabolic heat output of living organisms and heat production of exothermic chemical processes. Current advances in microfabrication have made possible the miniaturization of commercial microcalorimeters, resulting in a few studies on the metabolic activity of cells at the microscale in microfluidic chips. Here we present a new, versatile, and robust microcalorimetric differential design based on the integration of heat flux sensors on top of microfluidic channels. We show the design, modeling, calibration, and experimental verification of this system by utilizing Escherichia coli growth and the exothermic base catalyzed hydrolysis of methyl paraben as use cases. The system consists of a Polydimethylsiloxane based flow-through microfluidic chip with two 46 µl chambers and two integrated heat flux sensors. The differential compensation of thermal power measurements allows for the measurement of bacterial growth with a limit of detection of 1707 W/m3, corresponding to 0.021OD (2 ∙ 107 bacteria). We also extracted the thermal power of a single Escherichia coli of between 1.3 and 4.5 pW, comparable to values measured by industrial microcalorimeters. Our system opens the possibility for expanding already existing microfluidic systems, such as drug testing lab-on-chip platforms, with measurements of metabolic changes of cell populations in form of heat output, without modifying the analyte and minimal interference with the microfluidic channel itself.
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Affiliation(s)
- Signe L. K. Vehusheia
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
| | - Cosmin Roman
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
| | - Olivier Braissant
- Center of Biomechanics and Biocalorimetry, Department of Biomedical Engineering, University of Basel, Hegenheimermattweg 167C, 4123 Allschwil, Switzerland
| | - Markus Arnoldini
- Laboratory for Food Immunology, Department of Health Sciences and Technology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland
| | - Christofer Hierold
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland
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4
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Machado MH, Ribeiro DHB, Longhi DA, Carciofi BAM, Barreto PLM. Microcalorimetric growth behavior of E. coli ATCC 25922 in an MCDSC. J Microbiol Methods 2023; 205:106674. [PMID: 36641085 DOI: 10.1016/j.mimet.2023.106674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/31/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023]
Abstract
Isothermal microcalorimetry can provide a general analytical tool for the characterization of bacterial growth. Methodologies and equipment have been studied to expand the application and disseminate the use of the technique. The MCDSC is a microcalorimeter capable of measuring in the range of 0.2 μW that can operate at a temperature range of -20 to 140 °C or under isothermal conditions. Here, we present the first investigation of MCDSC for E. coli growth with the Baranyi and Roberts modeling application. This study presented the calorimetric E. coli fingerprint at MCDSC and compares it with the plate count technique, giving the data more biological meaning. The calorimeter was able to accurately detect growth metabolism and discriminate E. coli at different inoculum densities. Additionally, the MCDSC can offer a new point of view for evaluating microbial growth, such as the significant reduction in error due to dispersed data by the viable counting method.
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Affiliation(s)
- Michelle Heck Machado
- Department of Food Science and Technology, Federal University of Santa Catarina (UFSC), 88034-001 Florianópolis, SC, Brazil.
| | - Deise Helena Baggio Ribeiro
- Department of Food Science and Technology, Federal University of Santa Catarina (UFSC), 88034-001 Florianópolis, SC, Brazil
| | - Daniel Angelo Longhi
- School of Food Engineering, Federal University of Paraná (UFPR), 86900-000 Jandaia do Sul, PR, Brazil
| | - Bruno Augusto Mattar Carciofi
- Department of Chemical Engineering and Food Engineering, Federal University of Santa Catarina (UFSC), 88034-001 Florianópolis, SC, Brazil
| | - Pedro Luiz Manique Barreto
- Department of Food Science and Technology, Federal University of Santa Catarina (UFSC), 88034-001 Florianópolis, SC, Brazil
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5
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Baede VO, Tavakol M, Vos MC, Knight GM, van Wamel WJB. Dehydration Tolerance in Epidemic versus Nonepidemic MRSA Demonstrated by Isothermal Microcalorimetry. Microbiol Spectr 2022; 10:e0061522. [PMID: 35972129 PMCID: PMC9602581 DOI: 10.1128/spectrum.00615-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) clusters are considered epidemic or nonepidemic based on their ability to spread effectively. Successful transmission could be influenced by dehydration tolerance. Current methods for determination of dehydration tolerance lack accuracy. Here, a climate-controlled in vitro dehydration assay using isothermal microcalorimetry (IMC) was developed and linked with mathematical modeling to determine survival of 44 epidemic versus 54 nonepidemic MRSA strains from France, the United Kingdom, and the Netherlands after 1 week of dehydration. For each MRSA strain, the growth parameters time to end of first growth phase (tmax [h]) and maximal exponential growth rate (μm) were deduced from IMC data for 3 experimental replicates, 3 different starting inocula, and before and after dehydration. If the maximal exponential growth rate was within predefined margins (±36% of the mean), a linear relationship between tmax and starting inoculum could be utilized to predict log reduction after dehydration for individual strains. With these criteria, 1,330 of 1,764 heat flow curves (data sets) (75%) could be analyzed to calculate the post-dehydration inoculum size, and thus the log reduction due to dehydration, for 90 of 98 strains (92%). Overall reduction was ~1 log after 1 week. No difference in dehydration tolerance was found between the epidemic and nonepidemic strains. Log reduction was negatively correlated with starting inoculum, indicating better survival of higher inocula. This study presents a framework to quantify bacterial survival. MRSA strains showed great capacity to persist in the environment, irrespective of epidemiological success. This finding strengthens the need for effective surface cleaning to contain MRSA transmission. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of infections globally. While some MRSA clusters have spread worldwide, others are not able to disseminate successfully beyond certain regions despite frequent introduction. Dehydration tolerance facilitates transmission in hospital environments through enhanced survival on surfaces and fomites, potentially explaining differences in transmission success between MRSA clusters. Unfortunately, the currently available techniques to determine dehydration tolerance of cluster-forming bacteria like S. aureus are labor-intensive and unreliable due to their dependence on quantitative culturing. In this study, bacterial survival was assessed in a newly developed assay using isothermal microcalorimetry. With this technique, the effect of drying can be determined without the disadvantages of quantitative culturing. In combination with a newly developed mathematical algorithm, we determined dehydration tolerance of a large number of MRSA strains in a systematic, unbiased, and robust manner.
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Affiliation(s)
- Valérie O. Baede
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Mehri Tavakol
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Margreet C. Vos
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Gwenan M. Knight
- Centre for Mathematical Modelling of Infectious Diseases, Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Willem J. B. van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands
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Kaushal S, Shrivastava S, Yun YR, Park Y, Thanh-Qui Nguyen T, Meeseepong M, Lee E, Jeon B, Gu MB, Yang S, Lee NE. Culture-Free Quantification of Bacteria Using Digital Fluorescence Imaging in a Tunable Magnetic Capturing Cartridge for Onsite Food Testing. ACS Sens 2022; 7:2188-2197. [PMID: 35930745 DOI: 10.1021/acssensors.2c00372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Accurate, onsite detection of pathogenic bacteria from food matrices is required to rapidly respond to pathogen outbreaks. However, accurately detecting whole-cell bacteria in large sample volumes without an enrichment step remains a challenge. Therefore, bacterial samples must be concentrated, identified, and quantified. We developed a tunable magnetic capturing cartridge (TMCC) and combined it with a portable digital fluorescence reader for quick, onsite, quantitative detection of Staphylococcus aureus. The TMCC platform integrates an absorption pad impregnated with water-soluble polyvinyl alcohol (PVA) with an injection-molded polycarbonate (PC) plate that has a hard magnet on its back and an acrylonitrile-butadiene-styrene case. An S. aureus-specific antibody conjugated with magnetic nanoparticles was used to concentrate bacteria from a large-volume sample and capture bacteria within the TMCC. The retention time for capturing bacteria on the TMCC was adjusted by controlling the concentration and volume of the PVA solution. Concentrated bacterial samples bound to target-specific aptamer probes conjugated with quantum dots were loaded into the TMCC for a controlled time, followed by attachment of the bacteria to the PC plate and removal of unbound aptamer probes with wash buffer. The captured bacteria were quantified using a digital fluorescence reader equipped with an embedded program that automatically counts fluorescently tagged bacteria. The bacterial count made using the TMCC was comparable to a standard plate count (R2 = 0.9898), with assay sensitivity and specificity of 94.3 and 100%, respectively.
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Affiliation(s)
- Sandeep Kaushal
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea
| | - Sajal Shrivastava
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea
| | - Young-Ran Yun
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Younghyeon Park
- Department of Electrical and Computer Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Gyeonggi-do, Suwon 16419, Korea
| | - Thi Thanh-Qui Nguyen
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Montri Meeseepong
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea
| | - Eunghyuk Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea
| | - Byeungwoo Jeon
- Department of Electrical and Computer Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Gyeonggi-do, Suwon 16419, Korea
| | - Man Bock Gu
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Sung Yang
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,School of Mechanical Engineering, GIST, Gwangju 610005, Korea
| | - Nae-Eung Lee
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea.,SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea.,Institute of Quantum Biophysics (IQB), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Gyeonggi-do, Suwon 16419, Korea
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7
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Cichos KH, Spitler CA, Quade JH, Johnson JP, Johnson MD, Ghanem ES. Isothermal Microcalorimetry Improves the Time to Diagnosis of Fracture-related Infection Compared With Conventional Tissue Cultures. Clin Orthop Relat Res 2022; 480:1463-1473. [PMID: 35383603 PMCID: PMC9278947 DOI: 10.1097/corr.0000000000002186] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 03/04/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND A consensus definition recently was formulated for fracture-related infection, which centered on confirmatory criteria including conventional cultures that take time to finalize and have a 10% to 20% false-negative rate. During this time, patients are often on broad-spectrum antibiotics and may remain hospitalized until cultures are finalized to adjust antibiotic regimens. QUESTIONS/PURPOSES (1) What is the diagnostic accuracy of isothermal microcalorimetry, and how does its accuracy compare with that of conventional cultures? (2) Does isothermal microcalorimetry decrease time to detection (or diagnosis) of fracture-related infection compared with conventional cultures? (3) Does isothermal microcalorimetry have a diagnostic accuracy or time advantage over conventional cultures in patients on chronic suppressive antibiotics? METHODS Between July 2020 and August 2021, we treated 310 patients with concerns for infection after prior fracture repair surgery. Of those, we considered all patients older than 18 years of age with fixation hardware in place at the time of presentation as potentially eligible. All included patients returned to the operating room with cultures obtained and assessed by both isothermal microcalorimetry and conventional cultures, and all were diagnosed using the consensus criteria for fracture-related infection. Based on that, 81% (250 of 310) of patients were eligible; a further 51% (157 of 310) were excluded because of the following reasons: the capacity of the isothermal microcalorimetry instrument limited the throughput on that day (34% [106 of 310]), they had only swab cultures obtained in surgery (15% [46 of 310]), or they had less than 3 months follow-up after surgery for infectious concerns (2% [5 of 310]), leaving 30% (93 of 310) of the originally identified patients for analysis. We obtained two to five cultures from each patient during surgery, which were sent to our clinical microbiology laboratory for standard processing (conventional cultures). This included homogenization of each tissue sample individually and culturing for aerobic, anaerobic, acid-fast bacilli, and fungal culturing. The remaining homogenate from each sample was then taken to our orthopaedic research laboratory, resuspended in growth media, and analyzed by isothermal microcalorimetry for a minimum of 24 hours. Aerobic and anaerobic cultures were maintained for 5 days and 14 days, respectively. Overall, there were 93 patients (59 males), with a mean age of 43 ± 14 years and a mean BMI of 28 ± 8 kg/m 2 , and 305 tissue samples (mean 3 ± 1 samples per patient) were obtained and assessed by conventional culturing and isothermal microcalorimetry. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of isothermal microcalorimetry to diagnose fracture-related infection were compared with conventional cultures using a McNemar test based on the consensus definition of fracture-related infection. This consensus criteria is comprised of two levels of certainty for the diagnostic variables. The first is confirmatory criteria, where infection is considered definitely present and includes the presence of fistula/sinus tract/wound breakdown, purulent drainage or the presence of pus, presence of microorganisms in deep tissue specimens on histopathologic examination, presence of more than five neutrophils/high-powered field by histopathologic examination (only for chronic/late onset cases), and identification of phenotypically indistinguishable pathogens by conventional culture from at least two separate deep tissue/implant specimens. The second is suggestive criteria in which further investigation is required to achieve confirmatory status. Fracture-related infection was diagnosed for this study to minimize subjectivity based on the presence of at least one of the confirmatory criteria as documented by the managing surgeon. When suggestive criteria were present without confirmatory criteria, patients were considered negative for fracture-related infection and followed further in clinic after surgical exploration (n = 25 patients). All 25 patients deemed not to have fracture-related infection were considered infection-free at latest follow-up (range 3 to 12 months). The time to detection or diagnosis was recorded and compared via the Mann-Whitney U test. RESULTS Using the consensus criteria for fracture-related infection, there were no differences with the numbers available between isothermal microcalorimetry and conventional cultures in terms of sensitivity (87% [95% confidence interval 77% to 94%] versus 81% [95% CI 69% to 89%]), specificity (100% [95% CI 87% to 100%] versus 96% [95% CI 79% to 99%]), PPV (100% [95% CI 90% to 100%] versus 98% [95% CI 89% to 99%]), NPV (74% [95% CI 60% to 84%] versus 65% [95% CI 52% to 75%]), or accuracy (90% [95% CI 83% to 96%] versus 85% [95% CI 76% to 91%]; p = 0.13). The concordance by sample between conventional cultures and isothermal microcalorimetry was 85%. Isothermal microcalorimetry had a shorter median (range) time to detection or diagnosis compared with conventional cultures (2 hours [0.5 to 66] versus 51 hours [18 to 147], difference of medians 49 hours; p < 0.001). Additionally, 32 patients used antibiotics for a median (range) duration of 28 days (7 to 1095) before presentation. In these unique patients, there were no differences with the numbers available between isothermal microcalorimetry and conventional cultures in terms of sensitivity (89% [95% CI 71% to 98%] versus 74% [95% CI 53% to 88%]), specificity (100% [95% CI 48% to 100%] versus 83% [95% CI 36% to 99%]), PPV (100% [95% CI 85% to 100%] versus 95% [95% CI 77% to 99%]), NPV (63% [95% CI 37% to 83%] versus 42% [95% CI 26% to 60%]), or accuracy (91% [95% CI 75% to 98%] versus 78% [95% CI 57% to 89%]; p = 0.17). Isothermal microcalorimetry again had a shorter median (range) time to detection or diagnosis compared with conventional cultures (1.5 hours [0.5 to 48] versus 51.5 hours [18 to 125], difference of medians 50 hours; p < 0.001). CONCLUSION Given that isothermal microcalorimetry considerably decreases the time to the diagnosis of a fracture-related infection without compromising the accuracy of the diagnosis, managing teams may eventually use isothermal microcalorimetry-pending developmental improvements and regulatory approval-to rapidly detect infection and begin antibiotic management while awaiting speciation and susceptibility testing to modify the antibiotic regimen. Given the unique thermograms generated, further studies are already underway focusing on speciation based on heat curves alone. Additionally, increased study sizes are necessary for both overall fracture-related infection diagnostic accuracy and test performance on patients using long-term antibiotics given the promising results with regard to time to detection for this groups as well. LEVEL OF EVIDENCE Level II, diagnostic study.
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Affiliation(s)
- Kyle H. Cichos
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
| | - Clay A. Spitler
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
| | - Jonathan H. Quade
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
| | - Joseph P. Johnson
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
| | - Michael D. Johnson
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
| | - Elie S. Ghanem
- Department of Orthopaedic Surgery, University of
Alabama at Birmingham, Birmingham, AL, USA
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8
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Lee J, Abafogi AT, Oh S, Chang HE, Tepeng W, Lee D, Park S, Park KU, Hong YJ. Molecular detection of bacterial contamination in plasma using magnetic-based enrichment. Sci Rep 2022; 12:9151. [PMID: 35650226 PMCID: PMC9160056 DOI: 10.1038/s41598-022-12960-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/25/2022] [Indexed: 11/24/2022] Open
Abstract
Bacterial contamination of blood products is a major problem in transfusion medicine, in terms of both morbidity and mortality. Platelets (PLTs) are stored at room temperature (under constant agitation) for more than 5 days, and bacteria can thus grow significantly from a low level to high titers. However, conventional methods like blood culture and lateral flow assay have disadvantages such as long detection time, low sensitivity, and the need for a large volume of blood components. We used real-time polymerase chain reaction (PCR) assays with antibiotic-conjugated magnetic nanobeads (MNBs) to detect enriched Gram-positive and -negative bacteria. The MNBs were coated with polyethylene glycol (PEG) to prevent aggregation by blood components. Over 80% of all bacteria were captured by the MNBs, and the levels of detection were 101 colony forming unit [CFU]/mL and 102 CFU/mL for Gram-positive and -negative bacteria, respectively. The detection time is < 3 h using only small volumes of blood components. Thus, compared to conventional methods, real-time PCR using MNBs allows for rapid detection with high sensitivity using only a small volume of blood components.
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Affiliation(s)
- Jinyeop Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, South Korea.,KingoBio Inc. Research Center, Suwon, South Korea
| | | | - Sujin Oh
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | | | - Wu Tepeng
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, South Korea.,KingoBio Inc. Research Center, Suwon, South Korea
| | - Daekyu Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Sungsu Park
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, South Korea. .,Department of Biophysics, Institute of Quantum Biophysics (IQB), Sungkyunkwan University, Suwon, South Korea.
| | - Kyoung Un Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea.,Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Yun Ji Hong
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea. .,Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
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9
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Popa M, Cursaru A, Popa V, Munteanu A, Șerban B, Crețu B, Iordache S, Smarandache C, Orban C, Cîrstoiu C. Understanding orthopedic infections through a different perspective: Microcalorimetry growth curves. Exp Ther Med 2022; 23:263. [DOI: 10.3892/etm.2022.11189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/05/2021] [Indexed: 11/05/2022] Open
Affiliation(s)
- Mihnea Popa
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Adrian Cursaru
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Vlad Popa
- ‘Ilie Murgulescu’ Institute of Physical Chemistry, 060021 Bucharest, Romania
| | - Alexandru Munteanu
- Department of Medical Microbiology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Bogdan Șerban
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Bogdan Crețu
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Sergiu Iordache
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Catalin Smarandache
- Department of General Surgery, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Carmen Orban
- Department of Anaesthesia and Intensive Care, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Cătălin Cîrstoiu
- Department of Orthopedics and Traumatology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
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10
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Braissant O, Astasov-Frauenhoffer M, Waltimo T, Bonkat G. A Review of Methods to Determine Viability, Vitality, and Metabolic Rates in Microbiology. Front Microbiol 2020; 11:547458. [PMID: 33281753 PMCID: PMC7705206 DOI: 10.3389/fmicb.2020.547458] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/08/2020] [Indexed: 12/21/2022] Open
Abstract
Viability and metabolic assays are commonly used as proxies to assess the overall metabolism of microorganisms. The variety of these assays combined with little information provided by some assay kits or online protocols often leads to mistakes or poor interpretation of the results. In addition, the use of some of these assays is restricted to simple systems (mostly pure cultures), and care must be taken in their application to environmental samples. In this review, the necessary data are compiled to understand the reactions or measurements performed in many of the assays commonly used in various aspects of microbiology. Also, their relationships to each other, as metabolism links many of these assays, resulting in correlations between measured values and parameters, are discussed. Finally, the limitations of these assays are discussed.
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Affiliation(s)
- Olivier Braissant
- Department of Biomedical Engineering, Faculty of Medicine, University of Basel, Allschwil, Switzerland
| | | | - Tuomas Waltimo
- Department Research, University Center for Dental Medicine, University of Basel, Basel, Switzerland
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11
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Characterization of medical relevant anaerobic microorganisms by isothermal microcalorimetry. Anaerobe 2020; 66:102282. [PMID: 33017653 DOI: 10.1016/j.anaerobe.2020.102282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/27/2020] [Accepted: 10/01/2020] [Indexed: 12/20/2022]
Abstract
Detection of anaerobe bacteria by culture methods requires appropriate media, special growth conditions, additional detection techniques and it typically takes several days. Therefore, anaerobes are often missed in patient specimens under routine culture conditions. Microcalorimetry may provide a simple and accurate real-time method for faster and better detection of anaerobes. An isothermal calorimeter which detect minimal changes of temperature over time was used for the calorimetric experiments. In order to find optimal growth conditions, seven reference or clinical strains of medical relevant anaerobe bacteria were tested under different circumstances. First, the strains were tested with different growth media. After determining the optimal medium for each strain, the gas phase was modified by adding 3 mL or 4 mL medium, to evaluate growth under conditions with less oxygen. Cooked Meat Medium was best supporting growth of the tested strains, including Cutibacterium acnes, Fusobacterium nucleatum, Finegoldia magna, Parvimonas micra, Bacteroides fragilis and Actinomyces odontolyticus, followed by thioglycolate. The best medium to detect Clostridioides difficile was H-Medium. All tested strains showed better growth in 4 mL medium than in 3 mL. The detection time ranged between 10 and 72 h. Our results demonstrated that the sensitivity and the detection time of anaerobe bacteria can be improved by isothermal calorimetry with optimization of growth conditions. Therefore, calorimetric detection, a practical, quick and easy-to-do method, has the potential to replace current microbiological methods.
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12
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Liu Y, Lehnert T, Gijs MAM. Fast antimicrobial susceptibility testing on Escherichia coli by metabolic heat nanocalorimetry. LAB ON A CHIP 2020; 20:3144-3157. [PMID: 32677656 DOI: 10.1039/d0lc00579g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fast spreading of antimicrobial resistance is now considered a major global health threat. New technologies are required, enabling rapid diagnostics of bacterial infection combined with fast antimicrobial susceptibility testing (AST) for evaluating the efficiency and dosage of antimicrobial compounds in vitro. This work presents an integrated chip-based isothermal nanocalorimetry platform for direct microbial metabolic heat measurements and evaluates its potential for fast AST. Direct detection of the bacteria-generated heat allows monitoring of metabolic activity and antimicrobial action at subinhibitory concentrations in real-time. The high heat sensitivity of the platform enables bacterial growth detection within only a few hours of incubation, whereas growth inhibition upon administration of antibiotics is revealed by a decrease or the absence of the heat signal. Antimicrobial stress results in lag phase extension and metabolic energy spilling. Oxygen consumption and optical density measurements provide a more holistic insight of the metabolic state and the evolution of bacterial biomass. As a proof-of-concept, a metabolic heat-based AST study on Escherichia coli as model organism with 3 clinically relevant antibiotics is performed and the minimum inhibitory concentrations are determined.
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Affiliation(s)
- Yang Liu
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Thomas Lehnert
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Martin A M Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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13
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Yung PT, Lester E, Ponce A. Quantitative and Fast Sterility Assurance Testing of Surfaces by Enumeration of Germinable Endospores. Sci Rep 2020; 10:431. [PMID: 31949180 PMCID: PMC6965650 DOI: 10.1038/s41598-019-57175-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022] Open
Abstract
A fast Endospore Germinability Assay (EGA) was validated with traditional plate counts to enumerate single endospore germination events for monitoring surface sterilization. The assay is based on a time-gated luminescence microscopy technique enabling visualization and enumeration of individual germinating endospores. Germinating endospores release calcium dipicolinate to form highly luminescent terbium dipicolinate complexes surrounding each germinating endospore. EGA and heterotrophic plate counting (HPC) were used to evaluate the swab/rinse recovery efficiency of endospores from stainless steel surfaces. EGA and HPC results were highly correlated for endospore recovery from stainless steel coupons inoculated with range of 1,000 endospores per coupon down to sterility. Dosage-dependent decrease of surface endospore germinability were observed in dry heat, UV irradiation, oxygen plasma and vaporized hydrogen peroxide treatments, measured with EGA and HPC. EGA is a fast and complementary method to traditional HPC for quantitative sterility assurance testing of surfaces. This work introduces and validates a 15-minute or faster assay for germinable endospores to complement the conventional lengthy, culture-based surface sterility validation, which is critical in hospitals, food and pharmaceutical industries to help minimize nosocomial infection, food spoilage, and pharmaceutical contamination.
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Affiliation(s)
- Pun To Yung
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.,Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
| | - Elizabeth Lester
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Adrian Ponce
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. .,Verrix, LLC, San Clemente, CA, USA.
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14
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Fricke C, Harms H, Maskow T. Rapid Calorimetric Detection of Bacterial Contamination: Influence of the Cultivation Technique. Front Microbiol 2019; 10:2530. [PMID: 31736935 PMCID: PMC6838224 DOI: 10.3389/fmicb.2019.02530] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/21/2019] [Indexed: 11/13/2022] Open
Abstract
Modern isothermal microcalorimeters (IMC) are able to detect the metabolic heat of bacteria with an accuracy sufficient to recognize even the smallest traces of bacterial contamination of water, food, and medical samples. The modern IMC techniques are often superior to conventional detection methods in terms of the detection time, reliability, labor, and technical effort. What is missing is a systematic analysis of the influence of the cultivation conditions on calorimetric detection. For the acceptance of IMC techniques, it is advantageous if already standardized cultivation techniques can be combined with calorimetry. Here we performed such a systematic analysis using Lactobacillus plantarum as a model bacterium. Independent of the cultivation techniques, IMC detections were much faster for high bacterial concentrations (>102 CFU⋅mL-1) than visual detections. At low bacterial concentrations (<102 CFU⋅mL-1), detection times were approximately the same. Our data demonstrate that all kinds of traditional cultivation techniques like growth on agar (GOA) or in agar (GIA), in liquid media (GL) or on agar after enrichment via membrane filtration (GF) can be combined with IMC. The order of the detection times was GF < GIA ≈ GL ≈ GOA. The observed linear relationship between the calorimetric detection times and the initial bacterial concentrations can be used to quantify the bacterial contamination. Further investigations regarding the correlation between the filling level (in mm) of the calorimetric vessel and the specific maximum heat flow (in μW⋅g-1) illustrated two completely different results for liquid and solid media. Due to the better availability of substrates and the homogeneous distribution of bacteria growing in a liquid medium, the volume-related maximum heat flow was independent on the filling level of the calorimetric vessels. However, in a solid medium, the volume-related maximum heat flow approached a threshold and achieved a maximum at low filling levels. This fundamentally different behavior can be explained by the spatial limitation of the growth of bacterial colonies and the reduced substrate supply due to diffusion.
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Affiliation(s)
| | | | - Thomas Maskow
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
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15
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Kumar SS, Ghosh AR. Assessment of bacterial viability: a comprehensive review on recent advances and challenges. Microbiology (Reading) 2019; 165:593-610. [DOI: 10.1099/mic.0.000786] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Shravanthi S. Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
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16
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Rong X, Zhao G, Fein JB, Yu Q, Huang Q. Role of interfacial reactions in biodegradation: A case study in a montmorillonite, Pseudomonas sp. Z1 and methyl parathion ternary system. JOURNAL OF HAZARDOUS MATERIALS 2019; 365:245-251. [PMID: 30447631 DOI: 10.1016/j.jhazmat.2018.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/24/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
Organophosphate pesticides are currently the most commonly used pesticides, but the mechanisms of biodegradation of these compounds are often unknown. In this study, we constructed a ternary biodegradation system containing methyl parathion (MP), a bacterial strain of Pseudomonas sp. Z1 with capability of degrading MP and montmorillonite, which is a common clay mineral in soils. The role of interfacial reactions between montmorillonite and the MP degrader on the biodegradation of MP was investigated by batch adsorption as well as through semi-permeable membrane experiments. The contact between degrader and montmorillonite in biodegradation was also dynamically examined using in situ attenuated total reflectance Fourier transform infrared spectroscopy. The metabolic activity of the degrading bacteria was also assessed using an isothermal microcalorimetric technique. The results indicate that sorption of bacterial cells onto montmorillonite enhances the metabolic activity of the bacteria and hence the biodegradation of MP by the bacteria, and that an amide group on a bacterial surface protein is responsible for the bacterial adhesion onto the montmorillonite. This stimulated effect ceased when the bacteria were physically separated from the surface of the clay by a membrane, demonstrating the importance of sorption of both the bacteria and the MP in the biodegradation process.
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Affiliation(s)
- Xingmin Rong
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Gang Zhao
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Guangdong Institute of Microbiology, Chinese Academy of Science, Guangzhou 510070, China
| | - Jeremy B Fein
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Qiang Yu
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Qiaoyun Huang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
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17
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Ravn C, Furustrand Tafin U, Bétrisey B, Overgaard S, Trampuz A. Reduced ability to detect surface-related biofilm bacteria after antibiotic exposure under in vitro conditions. Acta Orthop 2016; 87:644-650. [PMID: 27775462 PMCID: PMC5119450 DOI: 10.1080/17453674.2016.1246795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background and purpose - Antibiotic treatment of patients before specimen collection reduces the ability to detect organisms by culture. We investigated the suppressive effect of antibiotics on the growth of non-adherent, planktonic, and surface-related biofilm bacteria in vitro by using sonication and microcalorimetry methods. Patients and methods - Biofilms of Staphylococcus aureus, S. epidermidis, Escherichia coli, and Propionibacterium acnes were formed on porous glass beads and exposed for 24 h to antibiotic concentrations from 1 to 1,024 times the minimal inhibitory concentration (MIC) of vancomycin, daptomycin, rifampin, flucloxacillin, or ciprofloxacin. The beads were then sonicated to dislodge biofilm, followed by culture and measurement of growth-related heat flow by microcalorimetry of the resulting sonication fluid. Results - Vancomycin did not inhibit the heat flow of staphylococci and P. acnes at concentrations ≤1,024 μg/mL, whereas flucloxacillin at >128 μg/mL inhibited S. aureus. Daptomycin inhibited heat flow of S. aureus, S. epidermidis, and P. acnes at lower concentrations (32-128 times MIC, p < 0.001). Rifampin showed inconsistent results in staphylococci due to random emergence of resistance, which was observed at concentrations ≤1,024 times MIC (i.e. 8 μg/mL). Ciprofloxacin inhibited heat flow of E. coli at ≥4 times MIC (i.e. ≥ 0.06 μg/mL). Interpretation - Whereas time-dependent antibiotics (i.e. vancomycin and flucloxacillin) showed only weak growth suppression, concentration-dependent drugs (i.e. daptomycin and ciprofloxacin) had a strong suppressive effect on bacterial growth and reduced the ability to detect planktonic and biofilm bacteria. Exposure to rifampin rapidly caused emergence of resistance. Our findings indicate that preoperative administration of antibiotics may have heterogeneous effects on the ability to detect biofilm bacteria.
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Affiliation(s)
- Christen Ravn
- Department of Orthopaedic Surgery and Traumatology, Odense University Hospital;,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark;,Correspondence:
| | | | - Bertrand Bétrisey
- Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Søren Overgaard
- Department of Orthopaedic Surgery and Traumatology, Odense University Hospital;,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Andrej Trampuz
- Center for Musculoskeletal Surgery, Charité - University Medicine Berlin, Berlin, Germany
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18
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Chen C, Qu F, Wang J, Xia X, Wang J, Chen Z, Ma X, Wei S, Zhang Y, Li J, Gong M, Wang R, Liu H, Yang Z, Li Y, Zhao Y, Xiao X. Antibacterial effect of different extracts from Wikstroemia indica on Escherichia coli based on microcalorimetry coupled with agar dilution method. JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2016; 123:1583-1590. [DOI: 10.1007/s10973-015-4999-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
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19
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Boillat-Blanco N, Furustrand Tafin U, Jaton K, Trampuz A. Susceptibility testing of Mycobacterium abscessus by isothermal microcalorimetry. Diagn Microbiol Infect Dis 2015. [PMID: 26210204 DOI: 10.1016/j.diagmicrobio.2015.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We evaluated a new method for susceptibility testing of a rapidly growing mycobacterium using real-time measurement of heat (microcalorimetry). MICs of 2 clinical Mycobacterium abscessus isolates were determined by microbroth dilution and E-test. For microcalorimetry, Middlebrook-7H10 agar+10% oleic acid-albumin-dextrose-catalase, containing amikacin, clarithromycin, linezolid, and ciprofloxacin was inoculated with ~10(5)CFU/mL. Heat production was measured at 37°C for 72h. Minimal heat inhibition concentration (MHIC) was defined as the lowest antibiotic concentration inhibiting growth-related heat production. Growth of M. abscessus was detected after a median of 16.5h (range, 8.5-26.9h). Heat detection was proportionally delayed with increasing concentration of antibiotics. MHICs for the tested strains were 16 to >16mg/L for amikacin, >8mg/L for clarithromycin, 4 to >16mg/L for ciprofloxacin, 24 to >32mg/L for linezolid. MHICs were in agreement within two 2-fold dilutions with conventional MICs. Microcalorimetry may accelerate antimicrobial susceptibility testing in mycobacteria and provide additional real-time information on the drug effect.
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Affiliation(s)
- Noémie Boillat-Blanco
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Ulrika Furustrand Tafin
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, Lausanne, Switzerland; Septic Surgical Unit, Department of Surgery, University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Katia Jaton
- Institute of Microbiology, University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Andrej Trampuz
- Center for Musculoskeletal Surgery, Charité - University Medicine, Free and Humboldt - University of Berlin, Berlin, Germany.
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20
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Microcalorimetric assays for measuring cell growth and metabolic activity: Methodology and applications. Methods 2015; 76:27-34. [DOI: 10.1016/j.ymeth.2014.10.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 11/16/2022] Open
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21
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Ferreira IS, Bettencourt A, Bétrisey B, Gonçalves LMD, Trampuz A, Almeida AJ. Improvement of the antibacterial activity of daptomycin-loaded polymeric microparticles by Eudragit RL 100: an assessment by isothermal microcalorimetry. Int J Pharm 2015; 485:171-82. [PMID: 25772414 DOI: 10.1016/j.ijpharm.2015.03.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/05/2015] [Accepted: 03/09/2015] [Indexed: 02/08/2023]
Abstract
The aim of the present study was to develop novel daptomycin-loaded acrylic microparticles with improved release profiles and antibacterial activity against two clinically relevant methicillin-susceptible and methicillin-resistant Staphylococcus aureus strains (MSSA and MRSA, respectively). Daptomycin was encapsulated into poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL 100 (EUD) microparticles by a double emulsion-solvent evaporation method. For comparison purposes similar formulations were prepared with vancomycin. Particle morphology, size distribution, encapsulation efficiency, surface charge, physicochemical properties, in vitro release and biocompatibility were assessed. Particles exhibited a micrometer size and a spherical morphology. The addition of EUD to the formulation caused a shift in the surface charge of the particles from negative zeta potential values (100% PMMA formulations) to strongly positive. It also improved daptomycin encapsulation efficiency and release, whereas vancomycin encapsulation and release were strongly hindered. Plain and antibiotic-loaded particles presented comparable biocompatibility profiles. The antibacterial activity of the particles was assessed by isothermal microcalorimetry against both MSSA and MRSA. Daptomycin-loaded PMMA-EUD particles presented the highest antibacterial activity against both strains. The addition of 30% EUD to the daptomycin-loaded PMMA particles caused a 40- and 20-fold decrease in the minimum inhibitory (MIC) and bactericidal concentration (MBC) values, respectively, when compared to the 100% PMMA formulations. On the other hand, vancomycin-loaded microparticles presented the highest antibacterial activity in PMMA particles. Unlike conventional methods, isothermal microcalorimetry proved to be a real-time, sensitive and accurate method for assessment of antibacterial activity of antibiotic-loaded polymeric microparticles. Finally, the addition of EUD to formulations proved to be a powerful strategy to improve daptomycin encapsulation efficiency and release, and consequently improving the microparticles activity against two relevant S. aureus strains.
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Affiliation(s)
- Inês Santos Ferreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal
| | - Ana Bettencourt
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal
| | - Bertrand Bétrisey
- Infectious Diseases Service, Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Lídia M D Gonçalves
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal
| | - Andrej Trampuz
- Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Free and Humboldt-University of Berlin, Berlin, Germany
| | - António J Almeida
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Portugal.
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22
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Lobete MM, Fernandez EN, Van Impe JFM. Recent trends in non-invasive in situ techniques to monitor bacterial colonies in solid (model) food. Front Microbiol 2015; 6:148. [PMID: 25798133 PMCID: PMC4351626 DOI: 10.3389/fmicb.2015.00148] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/09/2015] [Indexed: 12/29/2022] Open
Abstract
Planktonic cells typically found in liquid systems, are routinely used for building predictive models or assessing the efficacy of food preserving technologies. However, freely suspended cells often show different susceptibility to environmental hurdles than colony cells in solid matrices. Limited oxygen, water and nutrient availability, metabolite accumulation and physical constraints due to cell immobilization in the matrix, are main factors affecting cell growth. Moreover, intra- and inter-colony interactions, as a consequence of the initial microbial load in solid systems, may affect microbial physiology. Predictive food microbiology approaches are moving toward a more realistic resemblance to food products, performing studies in structured solid systems instead of liquids. Since structured systems promote microbial cells to become immobilized and grow as colonies, it is essential to study the colony behavior, not only for food safety assurance systems, but also for understanding cell physiology and optimizing food production processes in solid matrices. Traditionally, microbial dynamics in solid systems have been assessed with a macroscopic approach by applying invasive analytical techniques; for instance, viable plate counting, which yield information about overall population. In the last years, this approach is being substituted by more mechanistically inspired ones at mesoscopic (colony) and microscopic (cell) levels. Therefore, non-invasive and in situ monitoring is mandatory for a deeper insight into bacterial colony dynamics. Several methodologies that enable high-throughput data collection have been developed, such as microscopy-based techniques coupled with image analysis and OD-based measurements in microplate readers. This research paper provides an overview of non-invasive in situ techniques to monitor bacterial colonies in solid (model) food and emphasizes their advantages and inconveniences in terms of accuracy, performance and output information.
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Affiliation(s)
- María M. Lobete
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Estefania Noriega Fernandez
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jan F. M. Van Impe
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
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23
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Peñalba Arias P, Furustrand Tafin U, Bétrisey B, Vogt S, Trampuz A, Borens O. Activity of bone cement loaded with daptomycin alone or in combination with gentamicin or PEG600 against Staphylococcus epidermidis biofilms. Injury 2015; 46:249-53. [PMID: 25498330 DOI: 10.1016/j.injury.2014.11.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 11/11/2014] [Accepted: 11/16/2014] [Indexed: 02/02/2023]
Abstract
Daptomycin is a promising candidate for local treatment of bone infection due to its activity against multi-resistant staphylococci. We investigated the activity of antibiotic-loaded PMMA against Staphylococcus epidermidis biofilms using an ultra-sensitive method bacterial heat detection method (microcalorimetry). PMMA cylinders loaded with daptomycin alone or in combination with gentamicin or PEG600, vancomycin and gentamicin were incubated with S. epidermidis-RP62A in tryptic soy broth (TSB) for 72 h. Cylinders were thereafter washed and transferred in microcalorimetry ampoules pre-filled with TSB. Bacterial heat production, proportional to the quantity of biofilm on the PMMA, was measured by isothermal microcalorimetry at 37 °C. Heat detection time was considered time to reach 20 μW. Experiments were performed in duplicate. The heat detection time was 5.7-7.0 h for PMMA without antibiotics. When loaded with 5% of daptomycin, vancomycin or gentamicin, detection times were 5.6-16.4 h, 16.8-35.7 h and 4.7-6.2 h, respectively. No heat was detected when 5% gentamicin or 0.5% PEG600 was added to the daptomycin-loaded PMMA. The study showed that vancomycin was superior to daptomycin and gentamicin in inhbiting staphylococcal adherence in vitro. However, PMMA loaded with daptomycin combined with gentamicin or PEG600 completely inhibited S. epidermidis-biofilm formation. PMMA loaded with these combinations may represent effective strategies for local treatment in the presence of multi-resistant staphylococci.
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Affiliation(s)
- Patricio Peñalba Arias
- Service of Orthopaedics and Traumatology, Lausanne University Hospital, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland.
| | - Ulrika Furustrand Tafin
- Septic Surgical Unit, Lausanne University Hospital, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland.
| | - Bertrand Bétrisey
- Service of Infectious Diseases, Lausanne University Hospital, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland.
| | - Sebastian Vogt
- Research and Development, Heraeus Medical GmbH, Philipp-Reis-Straße 13, 61273 Wehrheim, Germany.
| | - Andrej Trampuz
- Center for Musculoskeletal Surgery, Charité-University Medicine, Free and Humboldt-University of Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Olivier Borens
- Service of Orthopaedics and Traumatology, Lausanne University Hospital, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland; Septic Surgical Unit, Lausanne University Hospital, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland.
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24
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Development of a flow system for studying biofilm formation on medical devices with microcalorimetry. Methods 2014; 76:35-40. [PMID: 25498003 DOI: 10.1016/j.ymeth.2014.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 01/06/2023] Open
Abstract
Isothermal microcalorimetry (IMC) is particularly suited to the study of microbiological samples in complex or heterogeneous environments because it does not require optical clarity of the sample and can detect metabolic activity from as few as 10(4) CFU/mL cells. While the use of IMC for studying planktonic cultures is well established, in the clinical environment bacteria are most likely to be present as biofilms. Biofilm prevention and eradication present a number of challenges to designers and users of medical devices and implants, since bacteria in biofilm colonies are usually more resistant to antimicrobial agents. Analytical tools that facilitate investigation of biofilm formation are therefore extremely useful. While it is possible to study pre-prepared biofilms in closed ampoules, better correlation with in vivo behaviour can be achieved using a system in which the bacterial suspension is flowing. Here, we discuss the potential of flow microcalorimetry for studying biofilms and report the development of a simple flow system that can be housed in a microcalorimeter. The use of the flow system is demonstrated with biofilms of Staphylococcus aureus.
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Yusuf E, Hügle T, Daikeler T, Voide C, Borens O, Trampuz A. The potential use of microcalorimetry in rapid differentiation between septic arthritis and other causes of arthritis. Eur J Clin Microbiol Infect Dis 2014; 34:461-5. [PMID: 25252631 DOI: 10.1007/s10096-014-2248-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/10/2014] [Indexed: 11/30/2022]
Abstract
Current diagnostic methods in differentiating septic from non-septic arthritis are time-consuming (culture) or have limited sensitivity (Gram stain). Microcalorimetry is a novel method that can rapidly detect microorganisms by their heat production. We investigated the accuracy and time to detection of septic arthritis by using microcalorimetry. Patients older than 18 years of age with acute arthritis of native joints were prospectively included. Synovial fluid was aspirated and investigated by Gram stain, culture and microcalorimetry. The diagnosis of septic arthritis and non-septic arthritis were made by experienced rheumatologists or orthopaedic surgeons. Septic arthritis was diagnosed by considering the finding of acute arthritis together with findings such as positive Gram stain or positive culture of synovial fluid or positive blood culture. The sensitivity and specificity for diagnosing septic arthritis and the time to positivity of microcalorimetry were determined. Of 90 patients (mean age 64 years), nine had septic arthritis, of whom four (44 %) had positive Gram stain, six (67 %) positive synovial fluid culture and four (44 %) had positive blood culture. The sensitivity of microcalorimetry was 89 %, the specificity was 99 % and the mean detection time was 5.0 h (range, 2.2-8.0 h). Microcalorimetry is an accurate and rapid method for the diagnosis of septic arthritis. It has potential to be used in clinical practice in diagnosing septic arthritis.
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Affiliation(s)
- E Yusuf
- Infectious Diseases Service, Department of Medicine, University Hospital, Lausanne, Switzerland,
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Yusuf E, Steinrücken J, Nordback S, Trampuz A. Necrotizing fasciitis after breast augmentation: rapid microbiologic detection by using sonication of removed implants and microcalorimetry. Am J Clin Pathol 2014; 142:269-72. [PMID: 25015872 DOI: 10.1309/ajcpna1zkvk7phud] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES To describe the use of sonication and microcalorimetry in diagnosing necrotizing fasciitis in a 27-year-old woman with bilateral breast implants. METHODS The removed breast implants were subjected to sonication and microcalorimetry. The microcalorimetry findings were correlated with conventional microbiologic methods. The time to detection of infection was noted. RESULTS The patient had painful cellulitis of the right breast that enlarged within hours. Her C-reactive protein level was increased. Chest radiograph showed gas formation in the soft tissue lateral of the right breast. Surgery was performed: 300 mL (right breast) and 100 mL (left breast) of serous-purulent fluid were evacuated. Streptococcus pyogenes was cultured from the fluid 1 day after clinical presentation. Infection was diagnosed by microcalorimetry of sonication fluid in 1 hour and 21 minutes. The microcalorimetry curve from the right implant reached the peak earlier than did the left implant. CONCLUSION Microcalorimetry will have a benefit in conditions in which rapid diagnosis of infection is important.
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Affiliation(s)
- Erlangga Yusuf
- Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Julia Steinrücken
- Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Sophie Nordback
- Plastic and Reconstructive Surgery, Department of Surgery and Anesthesiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Andrej Trampuz
- Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
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Activities of fluconazole, caspofungin, anidulafungin, and amphotericin B on planktonic and biofilm Candida species determined by microcalorimetry. Antimicrob Agents Chemother 2014; 58:2709-17. [PMID: 24566186 DOI: 10.1128/aac.00057-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We investigated the activities of fluconazole, caspofungin, anidulafungin, and amphotericin B against Candida species in planktonic form and biofilms using a highly sensitive assay measuring growth-related heat production (microcalorimetry). C. albicans, C. glabrata, C. krusei, and C. parapsilosis were tested, and MICs were determined by the broth microdilution method. The antifungal activities were determined by isothermal microcalorimetry at 37°C in RPMI 1640. For planktonic Candida, heat flow was measured in the presence of antifungal dilutions for 24 h. Candida biofilm was formed on porous glass beads for 24 h and exposed to serial dilutions of antifungals for 24 h, and heat flow was measured for 48 h. The minimum heat inhibitory concentration (MHIC) was defined as the lowest antifungal concentration reducing the heat flow peak by ≥50% (≥90% for amphotericin B) at 24 h for planktonic Candida and at 48 h for Candida biofilms (measured also at 24 h). Fluconazole (planktonic MHICs, 0.25 to >512 μg/ml) and amphotericin B (planktonic MHICs, 0.25 to 1 μg/ml) showed higher MHICs than anidulafungin (planktonic MHICs, 0.015 to 0.5 μg/ml) and caspofungin (planktonic MHICs, 0.125 to 0.5 μg/ml). Against Candida species in biofilms, fluconazole's activity was reduced by >1,000-fold compared to its activity against the planktonic counterparts, whereas echinocandins and amphotericin B mainly preserved their activities. Fluconazole induced growth of planktonic C. krusei at sub-MICs. At high concentrations of caspofungin (>4 μg/ml), paradoxical growth of planktonic C. albicans and C. glabrata was observed. Microcalorimetry enabled real-time evaluation of antifungal activities against planktonic and biofilm Candida organisms. It can be used in the future to evaluate new antifungals and antifungal combinations and to study resistant strains.
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Maskow T, Morais FM, Rosa LFM, Qian YG, Harnisch F. Insufficient oxygen diffusion leads to distortions of microbial growth parameters assessed by isothermal microcalorimetry. RSC Adv 2014. [DOI: 10.1039/c4ra03921a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oxygen limitation is an important, but often underestimated effect influencing microbial growth parameters derived from calorimetric routine measurements.
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Affiliation(s)
- Thomas Maskow
- UFZ – Helmholtz Centre for Environmental Research
- Department of Environmental Microbiology
- 04318 Leipzig, Germany
| | - Frida Mariana Morais
- UFZ – Helmholtz Centre for Environmental Research
- Department of Environmental Microbiology
- 04318 Leipzig, Germany
| | - Luis F. M. Rosa
- UFZ – Helmholtz Centre for Environmental Research
- Department of Environmental Microbiology
- 04318 Leipzig, Germany
| | - Yi G. Qian
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology & Sino-Hungarian Joint Laboratory of Environmental Science and Health
- China University of Geosciences
- 430074 Wuhan, PR China
| | - Falk Harnisch
- UFZ – Helmholtz Centre for Environmental Research
- Department of Environmental Microbiology
- 04318 Leipzig, Germany
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Störmer M, Vollmer T. Diagnostic methods for platelet bacteria screening: current status and developments. ACTA ACUST UNITED AC 2013; 41:19-27. [PMID: 24659944 DOI: 10.1159/000357651] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/20/2013] [Indexed: 11/19/2022]
Abstract
Bacterial contamination of blood components and the prevention of transfusion-associated bacterial infection still remains a major challenge in transfusion medicine. Over the past few decades, a significant reduction in the transmission of viral infections has been achieved due to the introduction of mandatory virus screening. Platelet concentrates (PCs) represent one of the highest risks for bacterial infection. This is due to the required storage conditions for PCs in gas-permeable containers at room temperature with constant agitation, which support bacterial proliferation from low contamination levels to high titers. In contrast to virus screening, since 1997 in Germany bacterial testing of PCs is only performed as a routine quality control or, since 2008, to prolong the shelf life to 5 days. In general, bacterial screening of PCs by cultivation methods is implemented by the various blood services. Although these culturing systems will remain the gold standard, the significance of rapid methods for screening for bacterial contamination has increased over the last few years. These new methods provide powerful tools for increasing the bacterial safety of blood components. This article summarizes the course of policies and provisions introduced to increase bacterial safety of blood components in Germany. Furthermore, we give an overview of the different diagnostic methods for bacterial screening of PCs and their current applicability in routine screening processes.
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Affiliation(s)
- Melanie Störmer
- Institut für Transfusionsmedizin, Blutspendezentrale, Universitätsklinikum Köln, Bad Oeynhausen, Germany
| | - Tanja Vollmer
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany
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Borens O, Yusuf E, Steinrücken J, Trampuz A. Accurate and early diagnosis of orthopedic device-related infection by microbial heat production and sonication. J Orthop Res 2013; 31:1700-3. [PMID: 23813873 DOI: 10.1002/jor.22419] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/05/2013] [Indexed: 02/04/2023]
Abstract
Proper and rapid diagnosis of orthopedic device-related infection is important for successful treatment. Sonication has been shown to improve the diagnostic performance. We hypothesized that the combination of sonication with a novel method called microcalorimetry will further improve and accelerate the diagnosis of implant infection. We prospectively included 39 consecutive patients (mean age 59 years, 62% males) at our institution from whom 29 orthopedic prostheses and 10 osteosynthesis material were explanted. The explanted device was sonicated. The resulting sonication fluid was analyzed using microcalorimetry. Using standardized criteria to define orthopedic device-related infection, 12 cases (31%) were defined as infected. In all, positive periprosthetic tissue cultures were found. The sensitivity and specificity of microcalorimetry of sonication fluid were 100% and 97%, respectively. Mean time to detection, defined as time to reach a rising heat flow signal of 20 µW measured after equilibiration needed to get accurate measurement, was 10.9 h. In summary, microcalorimetry of sonication fluid is a reliable and a fast method in detecting the presence of microorganisms in orthopedic device-related infection.
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Affiliation(s)
- Olivier Borens
- Orthopedic Septic Surgical Unit, Department of the Locomotor Apparatus and Department of Surgery and Anesthesiology, l, University of Lausanne, Lausanne University Hospital, BH-10 Rue du Bugnon 46, 1011, Lausanne, Switzerland
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Periprosthetic joint infections: clinical and bench research. ScientificWorldJournal 2013; 2013:549091. [PMID: 24288493 PMCID: PMC3826319 DOI: 10.1155/2013/549091] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 08/01/2013] [Indexed: 01/27/2023] Open
Abstract
Prosthetic joint infection is a devastating complication with high morbidity and substantial cost. The incidence is low but probably underestimated. Despite a significant basic and clinical research in this field, many questions concerning the definition of prosthetic infection as well the diagnosis and the management of these infections remained unanswered. We review the current literature about the new diagnostic methods, the management and the prevention of prosthetic joint infections.
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Activities of fosfomycin and rifampin on planktonic and adherent Enterococcus faecalis strains in an experimental foreign-body infection model. Antimicrob Agents Chemother 2013; 58:1284-93. [PMID: 24145537 DOI: 10.1128/aac.02583-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococcal implant-associated infections are difficult to treat because antibiotics generally lack activity against enterococcal biofilms. We investigated fosfomycin, rifampin, and their combinations against planktonic and adherent Enterococcus faecalis (ATCC 19433) in vitro and in a foreign-body infection model. The MIC/MBClog values were 32/>512 μg/ml for fosfomycin, 4/>64 μg/ml for rifampin, 1/2 μg/ml for ampicillin, 2/>256 μg/ml for linezolid, 16/32 μg/ml for gentamicin, 1/>64 μg/ml for vancomycin, and 1/5 μg/ml for daptomycin. In time-kill studies, fosfomycin was bactericidal at 8× and 16× MIC, but regrowth of resistant strains occurred after 24 h. With the exception of gentamicin, no complete inhibition of growth-related heat production was observed with other antimicrobials on early (3 h) or mature (24 h) biofilms. In the animal model, fosfomycin alone or in combination with daptomycin reduced planktonic counts by ≈4 log10 CFU/ml below the levels before treatment. Fosfomycin cleared planktonic bacteria from 74% of cage fluids (i.e., no growth in aspirated fluid) and eradicated biofilm bacteria from 43% of cages (i.e., no growth from removed cages). In combination with gentamicin, fosfomycin cleared 77% and cured 58% of cages; in combination with vancomycin, fosfomycin cleared 33% and cured 18% of cages; in combination with daptomycin, fosfomycin cleared 75% and cured 17% of cages. Rifampin showed no activity on planktonic or adherent E. faecalis, whereas in combination with daptomycin it cured 17% and with fosfomycin it cured 25% of cages. Emergence of fosfomycin resistance was not observed in vivo. In conclusion, fosfomycin showed activity against planktonic and adherent E. faecalis. Its role against enterococcal biofilms should be further investigated, especially in combination with rifampin and/or daptomycin treatment.
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Epidemiology and new developments in the diagnosis of prosthetic joint infection. Int J Artif Organs 2013; 35:923-34. [PMID: 23138706 DOI: 10.5301/ijao.5000168] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2012] [Indexed: 12/12/2022]
Abstract
Although prosthetic joint infection (PJI) is a rare event after arthroplasty, it represents a significant complication that is associated with high morbidity, need for complex treatment, and substantial healthcare costs. An accurate and rapid diagnosis of PJI is crucial for treatment success. Current diagnostic methods in PJI are insufficient with 10-30% false-negative cultures. Consequently, there is a need for research and development into new methods aimed at improving diagnostic accuracy and speed of detection. In this article, we review available conventional diagnostic methods for the diagnosis of PJI (laboratory markers, histopathology, synovial fluid and periprosthetic tissue cultures), new diagnostic methods (sonication of implants, specific and multiplex PCR, mass spectrometry) and innovative techniques under development (new laboratory markers, microcalorimetry, electrical method, reverse transcription [RT]-PCR, fluorescence in situ hybridization [FISH], biofilm microscopy, microarray identification, and serological tests). The results of highly sensitive diagnostic techniques with unknown specificity should be interpreted with caution. The organism identified by a new method may represent a real pathogen that was unrecognized by conventional diagnostic methods or contamination during specimen sampling, transportation, or processing. For accurate interpretation, additional studies are needed, which would evaluate the long-term outcome (usually >2 years) with or without antimicrobial treatment. It is expected that new rapid, accurate, and fully automatic diagnostic tests will be developed soon.
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Wernli L, Bonkat G, Gasser T, Bachmann A, Braissant O. Use of isothermal microcalorimetry to quantify the influence of glucose and antifungals on the growth of Candida albicans
in urine. J Appl Microbiol 2013; 115:1186-93. [DOI: 10.1111/jam.12306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 01/15/2023]
Affiliation(s)
- L. Wernli
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - G. Bonkat
- Department of Urology; University Hospital Basel; Basel Switzerland
- Laboratory of Biomechanics and Biocalorimetry (LOB2); Faculty of Medicine; University of Basel; Basel Switzerland
| | - T.C. Gasser
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - A. Bachmann
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - O. Braissant
- Department of Urology; University Hospital Basel; Basel Switzerland
- Laboratory of Biomechanics and Biocalorimetry (LOB2); Faculty of Medicine; University of Basel; Basel Switzerland
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In Vitro Activity of Gentamicin-Loaded Bioabsorbable Beads against Different Microorganisms. MATERIALS 2013; 6:3284-3293. [PMID: 28811436 PMCID: PMC5525159 DOI: 10.3390/ma6083284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/15/2013] [Accepted: 07/26/2013] [Indexed: 11/17/2022]
Abstract
Osteomyelitis is responsible for high treatment costs, long hospital stays, and results in substantial morbidity. Treatment with surgical debridement and antibiotic-impregnated Polymethylmetacrylate (PMMA) beads is the standard of care, providing high local but low serum antibiotic concentrations, thereby avoiding systemic toxicity. However, for several reasons, the beads require surgical removal. Alternative antibiotic delivery systems should improve the treatment of bone infection, actively encourage bone healing and require no additional surgery for removal. We investigated the activity of gentamicin-loaded bioabsorbable beads against different microorganisms (Staphylococcus epidermidis, S. aureus, Escherichia coli, Enterococcus faecalis, Candida albicans) commonly causing surgical site bone infection, by microcalorimetry. Calcium sulphate beads containing gentamicin were incubated in microcalorimetry ampoules containing different concentrations of the corresponding microorganism. Growth medium with each germ and unloaded beads was used as positive control, growth medium with loaded beads alone as negative control. Bacterial growth-related heat production at 37 °C was measured for 24 h. Cultures without gentamicin-loaded beads produced heat-flow peaks corresponding to the exponential growth of the corresponding microorganisms in nutrient-rich medium. In contrast, cultures with gentamicin-loaded beads completely suppressed heat production during 24 h, demonstrating their antibiotic activity. Gentamicin-loaded beads effectively inhibited growth of susceptible microorganisms, under the described in vitro conditions.
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Abstract
Advances in implant design, surgical technique, peri-operative antimicrobial prophylaxis and laminar airflow operating room environment have made total joint arthroplasty one of the most successful surgical procedures of all times. Orthopaedic implants, however, remain prone to microbial contamination resulting in persistent risk of implant-associated infection. Treatment of infections associated with orthopaedic devices usually requires appropriate surgical intervention combined with a prolonged antimicrobial therapy. The choice of the best possible treatment regimen depends on duration and pathogenesis of infection, stability of the implant, antimicrobial susceptibility of the pathogen and condition of the surrounding soft tissue. In addition towell known diagnostic procedures new promising tools for rapid and correct microbial diagnosis are being developed as correct diagnosis of the responsible micro-organism and this is paramount for successful treatment of prosthetic joint infection.
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Comparison of methods for evaluation of the bactericidal activity of copper-sputtered surfaces against methicillin-resistant Staphylococcus aureus. Appl Environ Microbiol 2012; 78:8176-82. [PMID: 22983970 DOI: 10.1128/aem.02266-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria can survive on hospital textiles and surfaces, from which they can be disseminated, representing a source of health care-associated infections (HCAIs). Surfaces containing copper (Cu), which is known for its bactericidal properties, could be an efficient way to lower the burden of potential pathogens. The antimicrobial activity of Cu-sputtered polyester surfaces, obtained by direct-current magnetron sputtering (DCMS), against methicillin-resistant Staphylococcus aureus (MRSA) was tested. The Cu-polyester microstructure was characterized by high-resolution transmission electron microscopy to determine the microstructure of the Cu nanoparticles and by profilometry to assess the thickness of the layers. Sputtering at 300 mA for 160 s led to a Cu film thickness of 20 nm (100 Cu layers) containing 0.209% (wt/wt) polyester. The viability of MRSA strain ATCC 43300 on Cu-sputtered polyester was evaluated by four methods: (i) mechanical detachment, (ii) microcalorimetry, (iii) direct transfer onto plates, and (iv) stereomicroscopy. The low efficacy of mechanical detachment impeded bacterial viability estimations. Microcalorimetry provided only semiquantitative results. Direct transfer onto plates and stereomicroscopy seemed to be the most suitable methods to evaluate the bacterial inactivation potential of Cu-sputtered polyester surfaces, since they presented the least experimental bias. Cu-polyester samples sputtered for 160 s by DCMS were further tested against 10 clinical MRSA isolates and showed a high level of bactericidal activity, with a 4-log(10) reduction in the initial MRSA load (10(6) CFU) within 1 h. Cu-sputtered polyester surfaces might be of use to prevent the transmission of HCAI pathogens.
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Lerchner J, Schulz A, Poeschel T, Wolf A, Hartmann T, Mertens F, Boschke E. Chip calorimetry and biomagnetic separation: Fast detection of bacterial contamination at low cell titers. Eng Life Sci 2012. [DOI: 10.1002/elsc.201200029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Johannes Lerchner
- TU Bergakademie Freiberg; Inst. Physical Chemistry; Freiberg; Germany
| | - Anne Schulz
- TU Bergakademie Freiberg; Inst. Physical Chemistry; Freiberg; Germany
| | - Theresa Poeschel
- Technische Universität Dresden; Inst. Food Technology and Bioprocess Engineering; Dresden; Germany
| | - Antje Wolf
- TU Bergakademie Freiberg; Inst. Physical Chemistry; Freiberg; Germany
| | - Tom Hartmann
- TU Bergakademie Freiberg; Inst. Physical Chemistry; Freiberg; Germany
| | - Florian Mertens
- TU Bergakademie Freiberg; Inst. Physical Chemistry; Freiberg; Germany
| | - Elke Boschke
- Technische Universität Dresden; Inst. Food Technology and Bioprocess Engineering; Dresden; Germany
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Bonkat G, Braissant O, Widmer AF, Frei R, Rieken M, Wyler S, Gasser TC, Wirz D, Daniels AU, Bachmann A. Rapid detection of urinary tract pathogens using microcalorimetry: principle, technique and first results. BJU Int 2012; 110:892-7. [DOI: 10.1111/j.1464-410x.2011.10902.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Doostmohammadi A, Monshi A, Fathi MH, Karbasi S, Braissant O, Daniels AU. Direct cytotoxicity evaluation of 63S bioactive glass and bone-derived hydroxyapatite particles using yeast model and human chondrocyte cells by microcalorimetry. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:2293-2300. [PMID: 21786131 DOI: 10.1007/s10856-011-4400-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 07/14/2011] [Indexed: 05/31/2023]
Abstract
In this study, the cytotoxicity evaluation of prepared 63S bioactive glass and bone-derived hydroxyapatite particles with yeast and human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. Elemental analysis was carried out by XRF and EDXRF. Amorphous structure of the glass and completely crystalline structure of HA were detected by XRD analysis. Finally, the cytotoxicity of bioactive glass and bone-derived HA particles with yeast and cultured human chondrocyte cells was evaluated using IMNC. The results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass, and bone-derived HA particles. Also the results indicated that yeast model which is much easier to handle, can be considered as a good proxy and can provide a rapid primary estimate of the ranges to be used in assays involving human cells. All of these results confirmed that IMNC is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods.
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Affiliation(s)
- A Doostmohammadi
- Biomaterials Group, Materials Engineering Department, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
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Potentials and limitations of miniaturized calorimeters for bioprocess monitoring. Appl Microbiol Biotechnol 2011; 92:55-66. [PMID: 21808971 DOI: 10.1007/s00253-011-3497-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 07/08/2011] [Accepted: 07/18/2011] [Indexed: 10/17/2022]
Abstract
In theory, heat production rates are very well suited for analysing and controlling bioprocesses on different scales from a few nanolitres up to many cubic metres. Any bioconversion is accompanied by a production (exothermic) or consumption (endothermic) of heat. The heat is tightly connected with the stoichiometry of the bioprocess via the law of Hess, and its rate is connected to the kinetics of the process. Heat signals provide real-time information of bioprocesses. The combination of heat measurements with respirometry is theoretically suited for the quantification of the coupling between catabolic and anabolic reactions. Heat measurements have also practical advantages. Unlike most other biochemical sensors, thermal transducers can be mounted in a protected way that prevents fouling, thereby minimizing response drifts. Finally, calorimetry works in optically opaque solutions and does not require labelling or reactants. It is surprising to see that despite all these advantages, calorimetry has rarely been applied to monitor and control bioprocesses with intact cells in the laboratory, industrial bioreactors or ecosystems. This review article analyses the reasons for this omission, discusses the additional information calorimetry can provide in comparison with respirometry and presents miniaturization as a potential way to overcome some inherent weaknesses of conventional calorimetry. It will be discussed for which sample types and scientific question miniaturized calorimeter can be advantageously applied. A few examples from different fields of microbiological and biotechnological research will illustrate the potentials and limitations of chip calorimetry. Finally, the future of chip calorimetry is addressed in an outlook.
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Gentamicin improves the activities of daptomycin and vancomycin against Enterococcus faecalis in vitro and in an experimental foreign-body infection model. Antimicrob Agents Chemother 2011; 55:4821-7. [PMID: 21807979 DOI: 10.1128/aac.00141-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
For enterococcal implant-associated infections, the optimal treatment regimen has not been defined. We investigated the activity of daptomycin, vancomycin, and gentamicin (and their combinations) against Enterococcus faecalis in vitro and in a foreign-body infection model. Antimicrobial activity was investigated by time-kill and growth-related heat production studies (microcalorimetry) as well as with a guinea pig model using subcutaneously implanted cages. Infection was established by percutaneous injection of E. faecalis in the cage. Antibiotic treatment for 4 days was started 3 h after infection. Cages were removed 5 days after end of treatment to determine the cure rate. The MIC, the minimal bactericidal concentration (MBC) in the logarithmic phase, and the MBC in the stationary phase were 1.25, 5, and >20 μg/ml for daptomycin, 1, >64, and >64 μg/ml for vancomycin, and 16, 32, and 4 μg/ml for gentamicin, respectively. In vitro, gentamicin at subinhibitory concentrations improved the activity against E. faecalis when combined with daptomycin or vancomycin in the logarithmic and stationary phases. In the animal model, daptomycin cured 25%, vancomycin 17%, and gentamicin 50% of infected cages. In combination with gentamicin, the cure rate for daptomycin increased to 55% and that of vancomycin increased to 33%. In conclusion, daptomycin was more active than vancomycin against adherent E. faecalis, and its activity was further improved by the addition of gentamicin. Despite a short duration of infection (3 h), the cure rates did not exceed 55%, highlighting the difficulty of eradicating E. faecalis from implants already in the early stage of implant-associated infection.
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Zaharia DC, Iancu C, Steriade AT, Muntean AA, Balint O, Popa VT, Popa MI, Bogdan MA. MicroDSC study of Staphylococcus epidermidis growth. BMC Microbiol 2010; 10:322. [PMID: 21162759 PMCID: PMC3018406 DOI: 10.1186/1471-2180-10-322] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 12/17/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A microcalorimetric study was carried out using a Staphylococcus epidermidis population to determine the reproducibility of bacterial growth and the variability of the results within certain experimental parameters (temperature, bacterial concentration, sample thermal history). Reproducibility tests were performed as series of experiments within the same conditions using either freshly prepared populations or samples kept in cold storage. In both cases, the samples were obtained by serial dilution from a concentrated TSB bacterial inoculum incubated overnight. RESULTS The results show that experiments are fairly reproducible and that specimens can be preserved at low temperatures (1 - 2°C) at least 4 days. The thermal signal variations at different temperatures and initial bacterial concentrations obey a set of rules that we identified. CONCLUSION Our study adds to the accumulating data and confirms available results of isothermal microcalorimetry applications in microbiology and can be used to standardize this method for either research or clinical setting.
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Affiliation(s)
- Dragos C Zaharia
- University of Medicine and Pharmacy, Carol Davila, Eroii Sanitari Bulevard 8, Bucharest, Romania
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Buchholz F, Harms H, Maskow T. Biofilm research using calorimetry - a marriage made in heaven? Biotechnol J 2010; 5:1339-50. [DOI: 10.1002/biot.201000287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Biomedical use of isothermal microcalorimeters. SENSORS 2010; 10:9369-83. [PMID: 22163413 PMCID: PMC3230962 DOI: 10.3390/s101009369] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/23/2010] [Accepted: 09/30/2010] [Indexed: 11/17/2022]
Abstract
Isothermal microcalorimetry is becoming widely used for monitoring biological activities in vitro. Microcalorimeters are now able to measure heat production rates of less than a microwatt. As a result, metabolism and growth of relatively small numbers of cultured bacteria, protozoans, human cells and even small animals can be monitored continuously and extremely accurately at any chosen temperature. Dynamic effects on these organisms of changes in the culture environment—or of additions to it—are easily assessed over periods from hours to days. In addition microcalorimetry is a non-destructive method that does not require much sample preparation. It is also completely passive and thus allows subsequent evaluations of any kind on the undisturbed sample. In this review, we present a basic description of current microcalorimetry instruments and an overview of their use for various biomedical applications. These include detecting infections, evaluating effects of pharmaceutical or antimicrobial agents on cells, monitoring growth of cells harvested for tissue eingineering, and assessing medical and surgical device material physico-chemical stability and cellular biocompatibility.
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Clauss M, Trampuz A, Borens O, Bohner M, Ilchmann T. Biofilm formation on bone grafts and bone graft substitutes: comparison of different materials by a standard in vitro test and microcalorimetry. Acta Biomater 2010; 6:3791-7. [PMID: 20226886 DOI: 10.1016/j.actbio.2010.03.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 02/14/2010] [Accepted: 03/05/2010] [Indexed: 02/03/2023]
Abstract
We analyzed the initial adhesion and biofilm formation of Staphylococcus aureus (ATCC 29213) and S. epidermidis RP62A (ATCC 35984) on various bone grafts and bone graft substitutes under standardized in vitro conditions. In parallel, microcalorimetry was evaluated as a real-time microbiological assay in the investigation of biofilm formation and material science research. The materials beta-tricalcium phosphate (beta-TCP), processed human spongiosa (Tutoplast) and poly(methyl methacrylate) (PMMA) were investigated and compared with polyethylene (PE). Bacterial counts (log(10) cfu per sample) were highest on beta-TCP (S. aureus 7.67 +/- 0.17; S. epidermidis 8.14 +/- 0.05) while bacterial density (log(10) cfu per surface) was highest on PMMA (S. aureus 6.12 +/- 0.2, S. epidermidis 7.65 +/- 0.13). Detection time for S. aureus biofilms was shorter for the porous materials (beta-TCP and processed human spongiosa, p < 0.001) compared to the smooth materials (PMMA and PE), with no differences between beta-TCP and processed human spongiosa (p > 0.05) or PMMA and PE (p > 0.05). In contrast, for S. epidermidis biofilms the detection time was different (p < 0.001) between all materials except between processed human spongiosa and PE (p > 0.05). The quantitative analysis by quantitative culture after washing and sonication of the material demonstrated the importance of monitoring factors like specific surface or porosity of the test materials. Isothermal microcalorimetry proved to be a suitable tool for an accurate, non-invasive and real-time microbiological assay, allowing the detection of bacterial biomass without removing the biofilm from the surface.
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Affiliation(s)
- Martin Clauss
- Department of Orthopedic Surgery, Kantonsspital Liestal, Liestal, Switzerland.
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Braissant O, Wirz D, Göpfert B, Daniels AU. Use of isothermal microcalorimetry to monitor microbial activities. FEMS Microbiol Lett 2010; 303:1-8. [DOI: 10.1111/j.1574-6968.2009.01819.x] [Citation(s) in RCA: 204] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Abstract
Bacterial contamination of platelet products, both single donor apheresis platelet units and whole blood-derived platelet pools, continues to occur despite preventive measures. While some advances have been made in decreasing the rate of bacterial contamination of platelet units, particularly through diversion methods and early culture, a great deal remains to be done to eliminate the problem. Diversion methods have decreased contamination rates associated with skin commensal organisms. Culture methods are now widely used and many at-issue detection methods have been developed or are undergoing development. This article reviews the current developments and the challenges that remain to minimize and detect bacterial contamination of platelet products.
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Chip calorimetry for fast and reliable evaluation of bactericidal and bacteriostatic treatments of biofilms. Antimicrob Agents Chemother 2009; 54:312-9. [PMID: 19822705 DOI: 10.1128/aac.00583-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chip calorimetry is introduced as a new monitoring tool that provides real-time information about the physiological state of biofilms. Its potential for use for the study of the effects of antibiotics and other biocides was tested. Established Pseudomonas putida biofilms were exposed to substances known to cause toxicity by different mechanisms and to provoke different responses of defense and resistance. The effects of these compounds on heat production rates were monitored and compared with the effects of these compounds on the numbers of CFU and intracellular ATP contents. The real-time monitoring potential of chip calorimetry was successfully demonstrated by using as examples the fast-acting poisons formaldehyde and 2,4-dinitrophenol (DNP). A dosage of antibiotics initially increased the heat production rate. This was discussed as being the effect of energy-dependent resistance mechanisms (e.g., export and/or transformation of the antibiotic). The subsequent reduction in the heat production rate was attributed to the loss of activity and the death of the biofilm bacteria. The shapes of the death curves were in agreement with the assumed variation in the levels of exposure of cells within the multilayer biofilms. The new monitoring tool provides fast, quantitative, and mechanistic insights into the acute and chronic effects of a compound on biofilm activity while requiring only minute quantities of the biocide.
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von Ah U, Wirz D, Daniels AU. Isothermal micro calorimetry--a new method for MIC determinations: results for 12 antibiotics and reference strains of E. coli and S. aureus. BMC Microbiol 2009; 9:106. [PMID: 19470161 PMCID: PMC2692853 DOI: 10.1186/1471-2180-9-106] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 05/26/2009] [Indexed: 11/17/2022] Open
Abstract
Background Antimicrobial susceptibility testing of microorganisms is performed by either disc diffusion or broth dilution tests. In clinical use, the tests are often still performed manually although automated systems exist. Most systems, however, are based on turbidometric methods which have well-known drawbacks. Results In this study we evaluated isothermal micro calorimetry (IMC) for the determination of minimal inhibitory concentrations (MICs) of 12 antibiotics for five micro-organisms. Here we present the data for the 12 antibiotics and two representative microorganisms E. coli (a Gram-) and S. aureus (a Gram+). IMC was able to determine the MICs correctly according to CLSI values. Since MICs require 24 hours, time was not reduced. However, IMC provided new additional data – a continuous record of heat-producing bacterial activity (e.g. growth) in calorimetry ampoules at subinhibitory antibiotic concentrations. Key features of the heatflow (P) and aggregate heat (Q) vs. time curves were identified (tdelay and ΔQ/Δt respectively). Antibiotics with similar modes of action proved to have similar effects on tdelay and/or ΔQ/Δt. Conclusion IMC can be a powerful tool for determining the effects of antibiotics on microorganisms in vitro. It easily provides accurate MICs – plus a potential means for analyzing and comparing the modes of action of antibiotics at subinhibitory concentrations. Also IMC is completely passive, so after evaluation, ampoule contents (media, bacteria, etc.) can be analyzed by any other method desired.
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Affiliation(s)
- Ueli von Ah
- Research Station Agroscope Liebefeld-Posieux ALP, Bern, Switzerland.
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