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Jalil AT, Alrawe RTA, Al-Saffar MA, Shaghnab ML, Merza MS, Abosaooda M, Latef R. The use of combination therapy for the improvement of colistin activity against bacterial biofilm. Braz J Microbiol 2024; 55:411-427. [PMID: 38030866 PMCID: PMC10920569 DOI: 10.1007/s42770-023-01189-7] [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: 07/14/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
Colistin is used as a last resort for the management of infections caused by multi-drug resistant (MDR) bacteria. However, the use of this antibiotic could lead to different side effects, such as nephrotoxicity, in most patients, and the high prevalence of colistin-resistant strains restricts the use of colistin in the clinical setting. Additionally, colistin could induce resistance through the increased formation of biofilm; biofilm-embedded cells are highly resistant to antibiotics, and as with other antibiotics, colistin is impaired by bacteria in the biofilm community. In this regard, the researchers used combination therapy for the enhancement of colistin activity against bacterial biofilm, especially MDR bacteria. Different antibacterial agents, such as antimicrobial peptides, bacteriophages, natural compounds, antibiotics from different families, N-acetylcysteine, and quorum-sensing inhibitors, showed promising results when combined with colistin. Additionally, the use of different drug platforms could also boost the efficacy of this antibiotic against biofilm. The mentioned colistin-based combination therapy not only could suppress the formation of biofilm but also could destroy the established biofilm. These kinds of treatments also avoided the emergence of colistin-resistant subpopulations, reduced the required dosage of colistin for inhibition of biofilm, and finally enhanced the dosage of this antibiotic at the site of infection. However, the exact interaction of colistin with other antibacterial agents has not been elucidated yet; therefore, further studies are required to identify the precise mechanism underlying the efficient removal of biofilms by colistin-based combination therapy.
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Affiliation(s)
| | | | - Montaha A Al-Saffar
- Community Health Department, Institute of Medical Technology/Baghdad, Middle Technical University, Baghdad, Iraq
| | | | - Muna S Merza
- Prosthetic Dental Techniques Department, Al-Mustaqbal University College, Babylon, 51001, Iraq
| | - Munther Abosaooda
- Medical Laboratory Technology Department, College of Medical Technology, The Islamic University, Najaf, Iraq
| | - Rahim Latef
- Medical Technical College, Al-Farahidi University, Baghdad, Iraq
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2
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Staphylococcus aureus and Acinetobacter sp. inhibit osseointegration of orthopaedic implants. Infect Immun 2022; 90:e0066921. [PMID: 35099267 DOI: 10.1128/iai.00669-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial infections routinely cause inflammation and thereby impair osseointegration of orthopaedic implants. Acinetobacter spp., which causes osteomyelitis following trauma, on or off the battlefield, was however reported to cause neither osteomyelitis nor osteolysis in rodents. We therefore compared the effects of Acinetobacter strain M2 to those of Staphylococcus aureus in a murine implant infection model. Sterile implants and implants with adherent bacteria were inserted in the femur of mice. Bacterial burden, levels of pro-inflammatory cytokines, and osseointegration were measured. All infections were localized to the implant site. Infection with either S. aureus or Acinetobacter strain M2 increased the levels of pro-inflammatory cytokines and the chemokine CCL2 in the surrounding femurs, inhibited bone formation around the implant, and caused loss of the surrounding cortical bone leading to decreases in both histomorphometric and biomechanical measures of osseointegration. Genetic deletion of TLR2 and TLR4 from the mice partially reduced the effects of Acinetobacter strain M2 on osseointegration but did not alter the effects of S. aureus. This is the first report that Acinetobacter spp. impair osseointegration of orthopaedic implants in mice and the murine model developed for this study will be useful for future efforts to clarify the mechanism of implant failure due to Acinetobacter spp. and to assess novel diagnostic tools or therapeutic agents.
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Veis DJ, Cassat JE. Infectious Osteomyelitis: Marrying Bone Biology and Microbiology to Shed New Light on a Persistent Clinical Challenge. J Bone Miner Res 2021; 36:636-643. [PMID: 33740314 DOI: 10.1002/jbmr.4279] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/01/2021] [Accepted: 02/19/2021] [Indexed: 12/11/2022]
Abstract
Infections of bone occur in a variety of clinical settings, ranging from spontaneous isolated infections arising from presumed hematogenous spread to those associated with skin and soft tissue wounds or medical implants. The majority are caused by the ubiquitous bacterium Staphyloccocus (S.) aureus, which can exist as a commensal organism on human skin as well as an invasive pathogen, but a multitude of other microbes are also capable of establishing bone infections. While studies of clinical isolates and small animal models have advanced our understanding of the role of various pathogen and host factors in infectious osteomyelitis (iOM), many questions remain unaddressed. Thus, there are many opportunities to elucidate host-pathogen interactions that may be leveraged toward treatment or prevention of this troublesome problem. Herein, we combine perspectives from bone biology and microbiology and suggest that interdisciplinary approaches will bring new insights to the field. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Deborah J Veis
- Division of Bone and Mineral Diseases, Departments of Medicine and Pathology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, MO, USA.,Shriners Hospitals for Children, St. Louis, MO, USA
| | - James E Cassat
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville,, TN, USA.,Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Institute for Infection, Immunology and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA
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4
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Bacteria-specific pro-photosensitizer kills multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Commun Biol 2021; 4:408. [PMID: 33767385 PMCID: PMC7994569 DOI: 10.1038/s42003-021-01956-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 03/04/2021] [Indexed: 11/30/2022] Open
Abstract
The emergence of multidrug-resistant bacteria has become a real threat and we are fast running out of treatment options. A combinatory strategy is explored here to eradicate multidrug-resistant Staphlococcus aureus and Pseudomonas aeruginosa including planktonic cells, established biofilms, and persisters as high as 7.5 log bacteria in less than 30 min. Blue-laser and thymol together rapidly sterilized acute infected or biofilm-associated wounds and successfully prevented systematic dissemination in mice. Mechanistically, blue-laser and thymol instigated oxidative bursts exclusively in bacteria owing to abundant proporphyrin-like compounds produced in bacteria over mammalian cells, which transformed harmless thymol into blue-laser sensitizers, thymoquinone and thymohydroquinone. Photo-excitations of thymoquinone and thymohydroquinone augmented reactive oxygen species production and initiated a torrent of cytotoxic events in bacteria while completely sparing the host tissue. The investigation unravels a previously unappreciated property of thymol as a pro-photosensitizer analogous to a prodrug that is activated only in bacteria. Multidrug-resistant bacteria are a real threat to human health. Here, the authors investigate a combinatory strategy using blue-laser and thymol against Staphylococcus aureus and Pseudomonas aeruginosa. Blue-laser and thymol succesfully sterilized acute infected or biofilm-associated wounds and prevented systematic dissemination in mice. Compared with mammalian cells, bacteria contain abundant proporphyrin-like compounds that transform harmless thymol into blue-laser sensitizers, thymoquinone and thymohydroquinone. Photo-excitation of thymoquinone and thymohydroquinone augmented reactive oxygen species production in bacteria while completely sparing the host tissue.
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5
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Schwarz EM, McLaren AC, Sculco TP, Brause B, Bostrom M, Kates SL, Parvizi J, Alt V, Arnold WV, Carli A, Chen AF, Choe H, Coraça‐Huber DC, Cross M, Ghert M, Hickok N, Jennings JA, Joshi M, Metsemakers W, Ninomiya M, Nishitani K, Oh I, Padgett D, Ricciardi B, Saeed K, Sendi P, Springer B, Stoodley P, Wenke JC. Adjuvant antibiotic-loaded bone cement: Concerns with current use and research to make it work. J Orthop Res 2021; 39:227-239. [PMID: 31997412 PMCID: PMC7390691 DOI: 10.1002/jor.24616] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 02/04/2023]
Abstract
Antibiotic-loaded bone cement (ALBC) is broadly used to treat orthopaedic infections based on the rationale that high-dose local delivery is essential to eradicate biofilm-associated bacteria. However, ALBC formulations are empirically based on drug susceptibility from routine laboratory testing, which is known to have limited clinical relevance for biofilms. There are also dosing concerns with nonstandardized, surgeon-directed, hand-mixed formulations, which have unknown release kinetics. On the basis of our knowledge of in vivo biofilms, pathogen virulence, safety issues with nonstandardized ALBC formulations, and questions about the cost-effectiveness of ALBC, there is a need to evaluate the evidence for this clinical practice. To this end, thought leaders in the field of musculoskeletal infection (MSKI) met on 1 August 2019 to review and debate published and anecdotal information, which highlighted four major concerns about current ALBC use: (a) substantial lack of level 1 evidence to demonstrate efficacy; (b) ALBC formulations become subtherapeutic following early release, which risks induction of antibiotic resistance, and exacerbated infection from microbial colonization of the carrier; (c) the absence of standardized formulation protocols, and Food and Drug Administration-approved high-dose ALBC products to use following resection in MSKI treatment; and (d) absence of a validated assay to determine the minimum biofilm eradication concentration to predict ALBC efficacy against patient specific micro-organisms. Here, we describe these concerns in detail, and propose areas in need of research.
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Affiliation(s)
- Edward M. Schwarz
- Department of Orthopaedics, Center for Musculoskeletal Research University of Rochester Rochester New York
| | - Alex C. McLaren
- Department of Orthopaedic Surgery, College of Medicine‐Phoenix University of Arizona Phoenix Arizona
| | - Thomas P. Sculco
- Department of Orthopaedic Surgery, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Barry Brause
- Department of Infectious Diseases, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Mathias Bostrom
- Department of Orthopaedic Surgery, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Stephen L. Kates
- Department of Orthopaedic Surgery Virginia Commonwealth University Richmond Virginia
| | - Javad Parvizi
- Department of Orthopaedics Rothman Institute at Thomas Jefferson University Hospital Philadelphia Pennsylvania
| | - Volker Alt
- Department of Trauma Surgery University Medical Centre Regensburg Regensburg Germany
| | - William V. Arnold
- Department of Orthopaedics Rothman Institute at Thomas Jefferson University Hospital Philadelphia Pennsylvania
| | - Alberto Carli
- Department of Orthopaedic Surgery, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Antonia F. Chen
- Department of Orthopaedics, Brigham and Women's Hospital Harvard Medical School Boston Massachusetts
| | - Hyonmin Choe
- Department of Orthopaedic Yokohama City University Yokohama Japan
| | - Débora C. Coraça‐Huber
- Department of Orthopaedic Surgery, Experimental Orthopedics, Research Laboratory for Biofilms and Implant Associated Infections Medical University of Innsbruck Innsbruck Austria
| | - Michael Cross
- Department of Orthopaedic Surgery, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Michelle Ghert
- Division of Orthopaedic Surgery, Department of Surgery McMaster University Hamilton Ontario Canada
| | - Noreen Hickok
- Department of Orthopaedic Surgery, Department of Biochemistry & Molecular Biology Thomas Jefferson University Philadelphia Pennsylvania
| | | | - Manjari Joshi
- Division of Infectious Diseases, R Adams Cowley Shock Trauma Center University of Maryland Baltimore Maryland
| | | | - Mark Ninomiya
- Department of Orthopaedics, Center for Musculoskeletal Research University of Rochester Rochester New York
| | - Kohei Nishitani
- Department of Orthopaedic Surgery Graduate School of Medicine, Kyoto University Sakyo Kyoto Japan
| | - Irvin Oh
- Department of Orthopaedics, Center for Musculoskeletal Research University of Rochester Rochester New York
| | - Douglas Padgett
- Department of Orthopaedic Surgery, Weill Cornell Medicine Hospital for Special Surgery New York New York
| | - Benjamin Ricciardi
- Department of Orthopaedics, Center for Musculoskeletal Research University of Rochester Rochester New York
| | - Kordo Saeed
- Southampton University Hospitals NHS Foundation Trust, Department of Microbiology, Microbiology and Innovation Research Unit (MIRU) and University of Southampton, School of Medicine Southampton UK
| | - Parham Sendi
- Institute for Infectious Diseases University of Bern, Bern and Department of Infectious Diseases, Hospital Epidemiology and Department of Orthopaedics and Traumatology, University of Basel Basel Switzerland
- Department of Orthopaedics and Traumatology University Hospital Basel Basel Switzerland
| | - Bryan Springer
- Department of Orthopaedic Surgery, OrthoCarolina Hip and Knee Center Atrium Musculoskeletal Institute Charlotte North Carolina
| | - Paul Stoodley
- Department of Microbial Infection and Immunity and Orthopaedics The Ohio State University Columbus Ohio
| | - Joseph C. Wenke
- Orthopaedic Trauma Department U.S. Army Institute of Surgical Research Fort Sam Houston Texas
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6
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Nezhadi J, Eslami H, Fakhrzadeh V, Moaddab SR, Zeinalzadeh E, Kafil HS. Photodynamic therapy of infection in burn patients. ACTA ACUST UNITED AC 2019. [DOI: 10.1097/mrm.0000000000000188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Morris FC, Dexter C, Kostoulias X, Uddin MI, Peleg AY. The Mechanisms of Disease Caused by Acinetobacter baumannii. Front Microbiol 2019; 10:1601. [PMID: 31379771 PMCID: PMC6650576 DOI: 10.3389/fmicb.2019.01601] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/26/2019] [Indexed: 01/29/2023] Open
Abstract
Acinetobacter baumannii is a Gram negative opportunistic pathogen that has demonstrated a significant insurgence in the prevalence of infections over recent decades. With only a limited number of “traditional” virulence factors, the mechanisms underlying the success of this pathogen remain of great interest. Major advances have been made in the tools, reagents, and models to study A. baumannii pathogenesis, and this has resulted in a substantial increase in knowledge. This article provides a comprehensive review of the bacterial virulence factors, the host immune responses, and animal models applicable for the study of this important human pathogen. Collating the most recent evidence characterizing bacterial virulence factors, their cellular targets and genetic regulation, we have encompassed numerous aspects important to the success of this pathogen, including membrane proteins and cell surface adaptations promoting immune evasion, mechanisms for nutrient acquisition and community interactions. The role of innate and adaptive immune responses is reviewed and areas of paucity in our understanding are highlighted. Finally, with the vast expansion of available animal models over recent years, we have evaluated those suitable for use in the study of Acinetobacter disease, discussing their advantages and limitations.
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Affiliation(s)
- Faye C Morris
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Carina Dexter
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Xenia Kostoulias
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Muhammad Ikhtear Uddin
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, Australia
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8
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Khan A, Xu M, Wang T, You C, Wang X, Ren H, Zhou H, Khan A, Han C, Li P. Catechol cross-linked antimicrobial peptide hydrogels prevent multidrug-resistant Acinetobacter baumannii infection in burn wounds. Biosci Rep 2019; 39:BSR20190504. [PMID: 31138760 PMCID: PMC6579981 DOI: 10.1042/bsr20190504] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/09/2019] [Accepted: 05/06/2019] [Indexed: 01/12/2023] Open
Abstract
Hospital-acquired infections are common in burn patients and are the major contributors of morbidity and mortality. Bacterial infections such as Staphylococcus aureus (S. aureus) and Acinetobacter baumannii (A. baumannii) are difficult to treat due to their biofilm formation and rapidly acquiring resistance to antibiotics. This work presents a newly developed hydrogel that has the potential for treating bacterial wound infections. The hydrogel formulation is based on an antimicrobial peptide (AMP), epsilon-poly-l-lysine (EPL) and catechol, which was cross-linked via mussel-inspired chemistry between the amine and phenol groups. In vitro studies showed that EPL-catechol hydrogels possess impressive antimicrobial and antibiofilm properties toward multidrug-resistant A. baumannii (MRAB). In addition, cytotoxicity study with the clonal mouse myoblast cell line (C2C12) revealed the good biocompatibility of this hydrogel. Furthermore, we created a second-degree burn wound on the mice dorsal skin surface followed by contamination with MRAB. Our results showed that the hydrogel significantly reduced the bacterial burden by more than four orders of magnitude in infected burn wounds. Additionally, there was no significant histological alteration with hydrogel application on mice skin. Based on these results, we concluded that EPL-catechol hydrogel is a promising future biomaterial to fight against multidrug-resistant bacterial infections.
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Affiliation(s)
- Abidullah Khan
- Department of Burns, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Miao Xu
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing 211816, China
| | - Tengjiao Wang
- Shaanxi Institute of Flexible Electronics (SIFE) and Institute of Biomedical Materials and Engineering (IBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Chuangang You
- Department of Burns, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Xingang Wang
- Department of Burns, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Haitao Ren
- Department of Burns, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Hongwei Zhou
- Department of Clinical Microbiology, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Amin Khan
- Department of Chemistry, University of Science and Technology, Bannu, Khyber Pakhtunkhwa (KPK) 28100, Pakistan
| | - Chunmao Han
- Department of Burns, Second Affiliated Hospital of Zhejiang University, School of Medicine, Jiefang Road 88, Hangzhou 310009, China
| | - Peng Li
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing 211816, China
- Shaanxi Institute of Flexible Electronics (SIFE) and Institute of Biomedical Materials and Engineering (IBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
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9
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Lu M, Dai T, Murray CK, Wu MX. Bactericidal Property of Oregano Oil Against Multidrug-Resistant Clinical Isolates. Front Microbiol 2018; 9:2329. [PMID: 30344513 PMCID: PMC6182053 DOI: 10.3389/fmicb.2018.02329] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/11/2018] [Indexed: 12/14/2022] Open
Abstract
Development of non-antibiotic alternatives to treat infections caused by multidrug-resistant (MDR) microbes represents one of the top priorities in healthcare and community settings, especially in the care of combat trauma-associated wound infections. Here, we investigate efficacy of oregano oil against pathogenic bacteria including MDR isolates from the combat casualties in vitro and in a mouse burn model. Oregano oil showed a significant anti-bacterial activity against 11 MDR clinical isolates including four Acinetobacter baumannii, three Pseudomonas aeruginosa, and four methicillin-resistant Staphylococcus aureus (MRSA) obtained from combat casualties and two luminescent strains of PA01 and MRSA USA300, with a MIC ranging from 0.08 mg/ml to 0.64 mg/ml. Oregano oil also effectively eradicated biofilms formed by each of the 13 pathogens above at similar MICs. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed that oregano oil damaged bacterial cells and altered the morphology of their biofilms. While efficiently inactivating bacteria, there was no evidence of resistance development after up to 20 consecutive passages of representative bacterial strains in the presence of sublethal doses of oregano oil. In vivo study using the third-degree burn wounds infected with PA01 or USA300 demonstrated that oregano oil, topically applied 24 h after bacterial inoculation, sufficiently reduced the bacterial load in the wounds by 3 log10 in 1 h, as measured by drastic reduction of bacterial bioluminescence. This bactericidal activity of oregano oil concurred with no significant side effect on the skin histologically or genotoxicity after three topical applications of oregano oil at 10 mg/ml for three consecutive days. The investigation suggests potentials of oregano oil as an alternative to antibiotics for the treatment of wound-associated infections regardless of antibiotic susceptibility.
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Affiliation(s)
- Min Lu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Tianhong Dai
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Clinton K Murray
- First Area Medical Laboratory, JBSA-Fort Sam Houston, Houston, TX, United States
| | - Mei X Wu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
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10
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Abstract
American survivability during the current conflicts in Iraq and Afghanistan continues to improve, though the rate of extremity injury remains quite high. The decision to proceed with amputation versus limb salvage remains controversial. Exposure to combat wound with severe high-energy lower extremity trauma during the previous 14 years at war has incited important advances in limb salvage technique and rehabilitation.
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11
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Personalized Therapeutic Cocktail of Wild Environmental Phages Rescues Mice from Acinetobacter baumannii Wound Infections. Antimicrob Agents Chemother 2016; 60:5806-16. [PMID: 27431214 DOI: 10.1128/aac.02877-15] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 07/06/2016] [Indexed: 02/08/2023] Open
Abstract
Multidrug-resistant bacterial pathogens are an increasing threat to public health, and lytic bacteriophages have reemerged as a potential therapeutic option. In this work, we isolated and assembled a five-member cocktail of wild phages against Acinetobacter baumannii and demonstrated therapeutic efficacy in a mouse full-thickness dorsal infected wound model. The cocktail lowers the bioburden in the wound, prevents the spread of infection and necrosis to surrounding tissue, and decreases infection-associated morbidity. Interestingly, this effective cocktail is composed of four phages that do not kill the parent strain of the infection and one phage that simply delays bacterial growth in vitro via a strong but incomplete selection event. The cocktail here appears to function in a combinatorial manner, as one constituent phage targets capsulated A. baumannii bacteria and selects for loss of receptor, shifting the population to an uncapsulated state that is then sensitized to the remaining four phages in the cocktail. Additionally, capsule is a known virulence factor for A. baumannii, and we demonstrated that the emergent uncapsulated bacteria are avirulent in a Galleria mellonella model. These results highlight the importance of anticipating population changes during phage therapy and designing intelligent cocktails to control emergent strains, as well as the benefits of using phages that target virulence factors. Because of the efficacy of this cocktail isolated from a limited environmental pool, we have established a pipeline for developing new phage therapeutics against additional clinically relevant multidrug-resistant pathogens by using environmental phages sourced from around the globe.
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12
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Sebe I, Ostorhazi E, Fekete A, Kovacs KN, Zelko R, Kovalszky I, Li W, Wade JD, Szabo D, Otvos L. Polyvinyl alcohol nanofiber formulation of the designer antimicrobial peptide APO sterilizes Acinetobacter baumannii-infected skin wounds in mice. Amino Acids 2015; 48:203-11. [PMID: 26319645 DOI: 10.1007/s00726-015-2080-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/20/2015] [Indexed: 12/20/2022]
Abstract
Native and designer cationic antimicrobial peptides are increasingly acknowledged as host defense molecules rather than true antimicrobials. Due to their ability to activate the innate immune system, these structures are used to treat uninfected and bacterially-infected wounds, including those harboring Acinetobacter baumannii. Previously we documented that when administered intramuscularly or topically in liquid formulations, the proline-rich host defense peptide dimer A3-APO accelerates uninfected wound re-epithelization and eliminates systemic and local A. baumannii, methicillin-resistant Staphylococcus aureus and other pathogen load from infected lesions better than conventional antibiotics. In the current study we sought to produce and characterize a novel delivery system, suitable for immediate and convenient application in non-hospital environments. The APO monomer was incorporated into polyvinyl alcohol nanofibers and the complex was polymerized into a solid patch dressing. Mice were subjected to skin abrasion where the wounds were either left uninfected or were inoculated with a near lethal dose of multidrug resistant A. baumannii strain. Analyzed after 3 days, APO monomer-containing patches improved wound appearance significantly better than polymer patches without antibiotics. When compared to colistin, the APO patches accelerated wound healing, and statistically significantly reduced wound size and wound bacterial load. The in vivo antimicrobial effect was more extensive than after intramuscular administration of the peptide drug, by using only one tenth of the active pharmaceutical ingredient. These data suggest that the APO monomer-impregnated nanofiber dressing can be developed as an economical first-line treatment option to skin injuries in general and battlefield burn and blast injuries in particular.
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Affiliation(s)
- Istvan Sebe
- University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hogyes Endre Street 7-9, Budapest, 1092, Hungary
| | - Eszter Ostorhazi
- Institute of Medical Microbiology, Semmelweis University, Nagyvarad ter 4, Budapest, 1089, Hungary.,Department of Laboratory Medicine, Semmelweis University, Nagyvarad ter 4, Budapest, 1089, Hungary
| | - Aron Fekete
- Institute of Medical Microbiology, Semmelweis University, Nagyvarad ter 4, Budapest, 1089, Hungary
| | - Krisztian N Kovacs
- Department of Polymer Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Muegyetem rkp. 3., Budapest, 1111, Hungary
| | - Romana Zelko
- University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hogyes Endre Street 7-9, Budapest, 1092, Hungary
| | - Ilona Kovalszky
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Ulloi ut 26, Budapest, 1085, Hungary
| | - Wenyi Li
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, 3010, Melbourne, VIC, Australia
| | - John D Wade
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, 3010, Melbourne, VIC, Australia
| | - Dora Szabo
- Institute of Medical Microbiology, Semmelweis University, Nagyvarad ter 4, Budapest, 1089, Hungary
| | - Laszlo Otvos
- Institute of Medical Microbiology, Semmelweis University, Nagyvarad ter 4, Budapest, 1089, Hungary. .,OLPE, LLC, 801 Mockingbird Lane, Audubon, PA, 19403, USA.
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13
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Gilbert SR, Camara J, Camara R, Duffy L, Waites K, Kim H, Zinn K. Contaminated open fracture and crush injury: a murine model. Bone Res 2015; 3:14050. [PMID: 26273534 PMCID: PMC4472147 DOI: 10.1038/boneres.2014.50] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/16/2014] [Accepted: 12/27/2014] [Indexed: 12/27/2022] Open
Abstract
Modern warfare has caused a large number of severe extremity injuries, many of which become infected. In more recent conflicts, a pattern of co-infection with Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus has emerged. We attempted to recreate this pattern in an animal model to evaluate the role of vascularity in contaminated open fractures. Historically, it has been observed that infected bones frequently appear hypovascular, but vascularity in association with bone infection has not been examined in animal models. Adult rats underwent femur fracture and muscle crush injury followed by stabilization and bacterial contamination with A. baumannii complex and methicillin-resistant Staphylococcus aureus. Vascularity and perfusion were assessed by microCT angiography and SPECT scanning, respectively, at 1, 2 and 4 weeks after injury. Quantitative bacterial cultures were also obtained. Multi-bacterial infections were successfully created, with methicillin-resistant S. aureus predominating. There was overall increase in blood flow to injured limbs that was markedly greater in bacteria-inoculated limbs. Vessel volume was greater in the infected group. Quadriceps atrophy was seen in both groups, but was greater in the infected group. In this animal model, infected open fractures had greater perfusion and vascularity than non-infected limbs.
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Affiliation(s)
- Shawn R Gilbert
- Department of Surgery, University of Alabama at Birmingham , AL USA
| | | | | | - Lynn Duffy
- Departments of Pathology, University of Alabama at Birmingham , AL USA
| | - Ken Waites
- Departments of Pathology, University of Alabama at Birmingham , AL USA
| | - Hyunki Kim
- Department of Radiology, University of Alabama at Birmingham , AL USA
| | - Kurt Zinn
- Department of Radiology, University of Alabama at Birmingham , AL USA
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Henslee AM, Shah SR, Wong ME, Mikos AG, Kasper FK. Degradable, antibiotic releasing poly(propylene fumarate)-based constructs for craniofacial space maintenance applications. J Biomed Mater Res A 2014; 103:1485-97. [DOI: 10.1002/jbm.a.35288] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/15/2014] [Accepted: 07/18/2014] [Indexed: 01/08/2023]
Affiliation(s)
| | - Sarita R. Shah
- Department of Bioengineering; Rice University; Houston Texas
| | - Mark E. Wong
- Department of Oral and Maxillofacial Surgery; The University of Texas Dental Branch; Houston Texas
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15
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Petersen K, Waterman P. Prophylaxis and treatment of infections associated with penetrating traumatic injury. Expert Rev Anti Infect Ther 2014; 9:81-96. [DOI: 10.1586/eri.10.155] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Zhang Y, Zhu Y, Gupta A, Huang Y, Murray CK, Vrahas MS, Sherwood ME, Baer DG, Hamblin MR, Dai T. Antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model: implications for prophylaxis and treatment of combat-related wound infections. J Infect Dis 2013; 209:1963-71. [PMID: 24381206 DOI: 10.1093/infdis/jit842] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In this study, we investigated the utility of antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model. A bioluminescent clinical isolate of multidrug-resistant A. baumannii was obtained. The susceptibility of A. baumannii to blue light (415 nm)-inactivation was compared in vitro to that of human keratinocytes. Repeated cycles of sublethal inactivation of bacterial by blue light were performed to investigate the potential resistance development of A. baumannii to blue light. A mouse model of third degree burn infected with A. baumannii was developed. A single exposure of blue light was initiated 30 minutes after bacterial inoculation to inactivate A. baumannii in mouse burns. It was found that the multidrug-resistant A. baumannii strain was significantly more susceptible than keratinocytes to blue light inactivation. Transmission electron microscopy revealed blue light-induced ultrastructural damage in A. baumannii cells. Fluorescence spectroscopy suggested that endogenous porphyrins exist in A. baumannii cells. Blue light at an exposure of 55.8 J/cm(2) significantly reduced the bacterial burden in mouse burns. No resistance development to blue light inactivation was observed in A. baumannii after 10 cycles of sublethal inactivation of bacteria. No significant DNA damage was detected in mouse skin by means of a skin TUNEL assay after a blue light exposure of 195 J/cm(2).
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Affiliation(s)
- Yunsong Zhang
- Wellman Center for Photomedicine Department of Dermatology, Harvard Medical School, Boston Department of Burn and Plastic Surgery, Guangzhou Red Cross Hospital, Jinan University, Guangzhou
| | - Yingbo Zhu
- Wellman Center for Photomedicine School of Medicine, Tongji University, Shanghai, China
| | - Asheesh Gupta
- Wellman Center for Photomedicine Department of Dermatology, Harvard Medical School, Boston Defense Institute of Physiology and Allied Sciences, Delhi, India
| | - Yingying Huang
- Wellman Center for Photomedicine Department of Dermatology, Harvard Medical School, Boston
| | | | - Mark S Vrahas
- Department of Orthopaedic Surgery, Massachusetts General Hospital
| | | | - David G Baer
- US Army Institute of Surgical Research, Fort Sam Houston, Texas
| | - Michael R Hamblin
- Wellman Center for Photomedicine Department of Dermatology, Harvard Medical School, Boston Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts
| | - Tianhong Dai
- Wellman Center for Photomedicine Department of Dermatology, Harvard Medical School, Boston
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17
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Synergistic effects and antibiofilm properties of chimeric peptides against multidrug-resistant Acinetobacter baumannii strains. Antimicrob Agents Chemother 2013; 58:1622-9. [PMID: 24366740 DOI: 10.1128/aac.02473-13] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The increasing prevalence of drug-resistant pathogens highlights the need to identify novel antibiotics. Here we investigated the efficacies of four new antimicrobial peptides (AMPs) for potential drug development. The antibacterial activities, synergistic effects, and antibiofilm properties of the four chimeric AMPs were tested against Acinetobacter baumannii, an emerging Gram-negative, nosocomial, drug-resistant pathogen. Nineteen A. baumannii strains resistant to ampicillin, cefotaxime, ciprofloxacin, tobramycin, and erythromycin were isolated at a hospital from patients with cholelithiasis. All four peptides exhibited significant antibacterial effects (MIC=3.12 to 12.5 μM) against all 19 strains, whereas five commercial antibiotics showed little or no activity against the same pathogens. An exception was polymyxin, which was effective against all of the strains tested. Each of the peptides showed synergy against one or more strains when administered in combination with cefotaxime, ciprofloxacin, or erythromycin. The peptides also exhibited an ability to prevent biofilm formation, which was not seen with cefotaxime, ciprofloxacin, or erythromycin, though polymyxin also inhibited biofilm formation. Indeed, when administered in combination with ciprofloxacin, the AMP HPMA exerted a potent synergistic effect against A. baumannii biofilm formation. Collectively, our findings indicate that the AMPs tested have no cytotoxicity but possess potent antibacterial and antibiofilm activities and may act synergistically with commercial antibiotics.
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18
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Ramírez P, Gordón M, Soriano A, Gil-Perotin S, Marti V, Gonzalez-Barbera EM, Sanchez-Aguilar MT, Simal JA, Bonastre J. Assessment of the in vivo formation of biofilm on external ventricular drainages. Eur J Clin Microbiol Infect Dis 2013; 32:1437-43. [DOI: 10.1007/s10096-013-1895-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/08/2013] [Indexed: 10/26/2022]
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McConnell MJ, Actis L, Pachón J. Acinetobacter baumannii: human infections, factors contributing to pathogenesis and animal models. FEMS Microbiol Rev 2012; 37:130-55. [PMID: 22568581 DOI: 10.1111/j.1574-6976.2012.00344.x] [Citation(s) in RCA: 350] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 04/30/2012] [Accepted: 05/03/2012] [Indexed: 11/30/2022] Open
Abstract
Acinetobacter baumannii has emerged as a medically important pathogen because of the increasing number of infections produced by this organism over the preceding three decades and the global spread of strains with resistance to multiple antibiotic classes. In spite of its clinical relevance, until recently, there have been few studies addressing the factors that contribute to the pathogenesis of this organism. The availability of complete genome sequences, molecular tools for manipulating the bacterial genome, and animal models of infection have begun to facilitate the identification of factors that play a role in A. baumannii persistence and infection. This review summarizes the characteristics of A. baumannii that contribute to its pathogenesis, with a focus on motility, adherence, biofilm formation, and iron acquisition. In addition, the virulence factors that have been identified to date, which include the outer membrane protein OmpA, phospholipases, membrane polysaccharide components, penicillin-binding proteins, and outer membrane vesicles, are discussed. Animal models systems that have been developed during the last 15 years for the study of A. baumannii infection are overviewed, and the recent use of these models to identify factors involved in virulence and pathogenesis is highlighted.
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Affiliation(s)
- Michael J McConnell
- Unit of Infectious Disease, Microbiology, and Preventive Medicine, Institute of Biomedicine of Sevilla (IBiS), University Hospital Virgen del Rocío/CSIC/University of Sevilla, Sevilla, Spain.
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20
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O'Shea MK. Acinetobacter in modern warfare. Int J Antimicrob Agents 2012; 39:363-75. [PMID: 22459899 DOI: 10.1016/j.ijantimicag.2012.01.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 01/24/2012] [Indexed: 10/28/2022]
Abstract
Increasing appreciation of the role of Acinetobacter baumannii in the aetiology of severe nosocomial infections, together with its ability to employ several mechanisms to rapidly develop resistance to multiple classes of antimicrobial agents, has led to growing interest in this organism over recent years. Recognition and subsequent investigation of the significance of pathogenic Acinetobacter infections in military personnel sustaining injuries during the conflicts in Afghanistan and Iraq has provided an important contribution to the epidemiology of infections with Acinetobacter spp. The following review examines this recent military experience.
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Affiliation(s)
- M K O'Shea
- Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK.
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21
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Shandley S, Matthews KP, Cox J, Romano D, Abplanalp A, Kalns J. Hyperbaric oxygen therapy in a mouse model of implant-associated osteomyelitis. J Orthop Res 2012; 30:203-8. [PMID: 21815206 DOI: 10.1002/jor.21522] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 07/14/2011] [Indexed: 02/04/2023]
Abstract
Implant associated osteomyelitis (OM) is difficult to treat with antibiotics, and outcomes remain poor. Some reports suggest that hyperbaric oxygen treatment is a safe and effective means of treating OM. We tested this hypothesis in a murine model. Clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae were used. The mice were infected with each of the three pathogens, treated with 100% oxygen at high pressure, hyperbaric oxygen (HBO), and monitored for the ability of HBO to prevent and/or clear the OM infection. Assessments included bacterial burden of the tibias and lesion scores, as well as receptor activator of NF-κB ligand (RANKL) and myeloperoxidase (MPO) concentrations. HBO resulted in more severe lesion scores and higher RANKL and MPO concentrations for MRSA. A significant positive correlation was found between RANKL concentration and lesion score. No significant difference was found with HBO in P. aeruginosa infections and K. pneumoniae seems to either not infect bone well or get cleared before establishing an infection. The model is useful for studying OM infections caused by MRSA and P. aeruginosa, but HBO does not appear to be an efficacious treatment of an implant-associated OM infection.
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Abstract
During combat operations, extremities continue to be the most common sites of injury with associated high rates of infectious complications. Overall, ∼ 15% of patients with extremity injuries develop osteomyelitis, and ∼ 17% of those infections relapse or recur. The bacteria infecting these wounds have included multidrug-resistant bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Klebsiella species and Escherichia coli, and methicillin-resistant Staphylococcus aureus. The goals of extremity injury care are to prevent infection, promote fracture healing, and restore function. In this review, we use a systematic assessment of military and civilian extremity trauma data to provide evidence-based recommendations for the varying management strategies to care for combat-related extremity injuries to decrease infection rates. We emphasize postinjury antimicrobial therapy, debridement and irrigation, and surgical wound management including addressing ongoing areas of controversy and needed research. In addition, we address adjuvants that are increasingly being examined, including local antimicrobial therapy, flap closure, oxygen therapy, negative pressure wound therapy, and wound effluent characterization. This evidence-based medicine review was produced to support the Guidelines for the Prevention of Infections Associated With Combat-Related Injuries: 2011 Update contained in this supplement of Journal of Trauma.
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Eardley WGP, Brown KV, Bonner TJ, Green AD, Clasper JC. Infection in conflict wounded. Philos Trans R Soc Lond B Biol Sci 2011; 366:204-18. [PMID: 21149356 DOI: 10.1098/rstb.2010.0225] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although mechanisms of modern military wounding may be distinct from those of ancient conflicts, the infectious sequelae of ballistic trauma and the evolving microbial flora of war wounds remain a considerable burden on both the injured combatant and their deployed medical systems. Battlefield surgeons of ancient times favoured suppuration in war wounding and as such Galenic encouragement of pus formation would hinder progress in wound care for centuries. Napoleonic surgeons eventually abandoned this mantra, embracing radical surgical intervention, primarily by amputation, to prevent infection. Later, microscopy enabled identification of microorganisms and characterization of wound flora. Concurrent advances in sanitation and evacuation enabled improved outcomes and establishment of modern military medical systems. Advances in medical doctrine and technology afford those injured in current conflicts with increasing survivability through rapid evacuation, sophisticated resuscitation and timely surgical intervention. Infectious complications in those that do survive, however, are a major concern. Addressing antibiotic use, nosocomial transmission and infectious sequelae are a current clinical management and research priority and will remain so in an era characterized by a massive burden of combat extremity injury. This paper provides a review of infection in combat wounding from a historical setting through to the modern evidence base.
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Affiliation(s)
- W G P Eardley
- Academic Department of Military Trauma and Surgery, Royal Centre for Defence Medicine, Academic and Research Directorate, West Wing, Institute of Research and Development, Vincent Drive, Birmingham B15 2SQ, UK
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24
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Shi M, Kretlow JD, Spicer PP, Tabata Y, Demian N, Wong ME, Kasper FK, Mikos AG. Antibiotic-releasing porous polymethylmethacrylate/gelatin/antibiotic constructs for craniofacial tissue engineering. J Control Release 2011; 152:196-205. [PMID: 21295086 DOI: 10.1016/j.jconrel.2011.01.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 01/13/2011] [Accepted: 01/25/2011] [Indexed: 12/23/2022]
Abstract
An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous PMMA constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6±1.8% and 38.4±1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 μg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct.
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Affiliation(s)
- Meng Shi
- Department of Bioengineering, Rice University, TX, USA
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25
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Acinetobacter baumannii is not associated with osteomyelitis in a rat model: a pilot study. Clin Orthop Relat Res 2011; 469:274-82. [PMID: 20668970 PMCID: PMC3008889 DOI: 10.1007/s11999-010-1488-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 07/15/2010] [Indexed: 01/31/2023]
Abstract
BACKGROUND Multidrug resistant Acinetobacter baumannii (MDR AB) with and without Staphylococcus aureus (SA) is a commonly isolated organism in infected segmental bone defects in combat-related trauma in Iraq and Afghanistan. Although MDR AB in visceral infections is a therapeutic challenge, control of infection appears more common for combat-related osteomyelitis. QUESTIONS/PURPOSES Using a rat model, we explored the virulence of MDR AB in segmental bone defects alone and in combination with SA. METHODS Segmental defects in 60 rat femurs were created, stabilized, and inoculated with MDR AB alone and 60 with MDR AB and SA. We performed qualitative and quantitative bacteriology and radiographic assessments at 2, 4, and 8 weeks for MDR AB and at 1, 2, and 3 weeks for MDR AB and SA. RESULTS Quantitative bacteriology revealed a 3- to 5-log decrease in MDR AB from the initial inoculum. After polymicrobial inoculation, only 10 of 60 animals had positive cultures for MDR AB, whereas 59 of 60 animals had positive cultures for SA. Recovered SA were 2 to 5 log greater than the initial inoculum, while there again was a 3- to 5-log decrease in MDR AB. MDR AB alone did not cause bony lysis, but there was radiographic evidence of new bone formation in 67% of the segmental defects. Osteolysis was noted with MDR AB and SA. CONCLUSIONS MDR AB did not appear to cause or contribute to clinically apparent osteomyelitis in this pilot study. CLINICAL RELEVANCE Resolution of infections in combat-related segmental bone defects inoculated with MDR AB may be attributable to low virulence. Additional studies are needed to confirm low virulence and bone formation with MDR AB.
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Ostorhazi E, Rozgonyi F, Sztodola A, Harmos F, Kovalszky I, Szabo D, Knappe D, Hoffmann R, Cassone M, Wade JD, Bonomo RA, Otvos L. Preclinical advantages of intramuscularly administered peptide A3-APO over existing therapies in Acinetobacter baumannii wound infections. J Antimicrob Chemother 2010; 65:2416-22. [PMID: 20810424 DOI: 10.1093/jac/dkq337] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES The designer antibacterial peptide A3-APO is efficacious in mouse models of Escherichia coli and Acinetobacter baumannii systemic infections. Here we compare the efficacy of the peptide with that of imipenem and colistin in A. baumannii wound infections after burn injury. METHODS CD-1 mice were inflicted with burn wounds and different inocula of A. baumannii, isolated from an injured soldier, were placed into the wound sites. The antibiotics were given intramuscularly (im) one to five times. Available free peptide in the blood and the systemic toxicity of colistin and A3-APO were studied in healthy mice. RESULTS While toxicity of colistin was observed at 25 mg/kg bolus drug administration, the lowest toxic dose of A3-APO was 75 mg/kg. In the A. baumannii blast injury models, 5 mg/kg A3-APO improved survival and reduced bacterial counts in the blood as well as in the wounds and improved wound appearance significantly better than any other antibiotic treatment. The free peptide concentration in the blood did not reach 1 µg/mL. CONCLUSIONS Peptide A3-APO, with an intramuscular therapeutic index of 15, is more efficacious and less toxic than any existing burn injury infection therapy modality against multidrug-resistant Gram-negative pathogens. A3-APO administered by the im route probably binds to a biopolymer that promotes the peptide's biodistribution.
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Affiliation(s)
- Eszter Ostorhazi
- Department of Dermatology, Venerology and Dermatooncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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27
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Shi M, Kretlow JD, Nguyen A, Young S, Baggett LS, Wong ME, Kasper FK, Mikos AG. Antibiotic-releasing porous polymethylmethacrylate constructs for osseous space maintenance and infection control. Biomaterials 2010; 31:4146-56. [PMID: 20153893 PMCID: PMC2839066 DOI: 10.1016/j.biomaterials.2010.01.112] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 01/19/2010] [Indexed: 02/06/2023]
Abstract
The use of a strategy involving space maintenance as the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite tissue defects in the craniofacial area, preserves the void volume of bony defects and could promote soft tissue healing prior to the subsequent definitive repair. One of the complications with a biomaterial-based space maintenance approach is local infection, which requires early, effective eradication, ideally through local antibiotic delivery. The purpose of this study is to develop a dual function implant material for maintaining osseous space and releasing an antibiotic to eliminate local infection in bony defects. Colistin, a polymyxin antibiotic, was chosen specifically to address infections with Acinetobacter species, the most common pathogen associated with combat-related traumatic craniofacial injuries. Porous polymethylmethacrylate (PMMA) constructs incorporating poly(lactic-co-glycolic acid) (PLGA) microspheres were fabricated by mixing a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid with a carboxymethylcellulose (CMC) hydrogel (40 or 50 wt%) to impart porosity and PLGA microspheres (10 or 15 wt%) loaded with colistin to control drug release. The PMMA/CMC/PLGA construct featured mild setting temperature, controllable surface/bulk porosity by incorporation of the CMC hydrogel, reasonably strong compressive properties, and continuous drug release over a period of 5 weeks with total drug release of 68.1-88.3%, depending on the weight percentage of CMC and PLGA incorporation. The concentration of released colistin was well above its reported minimum inhibitory concentration against susceptible species for 5 weeks. This study provides information on the composition parameters that enable viable porosity characteristics/drug release kinetics of the PMMA/CMC/PLGA construct for the initial space maintenance as part of a two-stage regenerative medicine approach.
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Affiliation(s)
- Meng Shi
- Department of Bioengineering, Rice University, Houston, TX USA
| | | | - Anson Nguyen
- School of Medicine, University of Texas Medical Branch at Galveston, Galveston, TX USA
| | - Simon Young
- Department of Bioengineering, Rice University, Houston, TX USA
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at Houston, Houston, TX USA
| | | | - Mark E. Wong
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at Houston, Houston, TX USA
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