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Doub JB, Heil EL, Manson T. Adjuvant intra-articular vancomycin for recalcitrant Staphylococcal prosthetic joint infections of the knee. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY & TRAUMATOLOGY : ORTHOPEDIE TRAUMATOLOGIE 2024; 34:1031-1036. [PMID: 37864658 DOI: 10.1007/s00590-023-03764-y] [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: 07/28/2023] [Accepted: 10/09/2023] [Indexed: 10/23/2023]
Abstract
OBJECTIVE Chronic prosthetic joint infection patients who fail conventional two-stage revision surgery are an especially difficult to treat patient population. Consequently, the objective of this study was to investigate the safety and long-term effectiveness of adjuvant intra-articular vancomycin therapy in conjunction with two-stage revision knee arthroplasties for recalcitrant Staphylococcal prosthetic joint infections. METHODS This was an observational cohort study of twelve patients with recalcitrant Staphylococcal prosthetic joint infections of the knee which had failed previous revision surgeries. Each patient subsequently underwent two-stage revision with placement of Hickman catheters to deliver intra-articular vancomycin therapy. In addition, systemic antibiotic therapy was administered for 6 weeks, and long-term follow-up was evaluated then for 5 years. RESULTS Seventy-five percent of the cohort have had no recurrence of their infections at 5 years. Two patients formed fistulas requiring above the knee amputations, and three patients had acute kidney injury. All patients had maximum measurable serum vancomycin trough levels that ranged from 6.1 to 93.6 mcg/mL. CONCLUSION The aggressive protocol used in this cohort with repeat two-stage revision surgery, intra-articular vancomycin and systemic antibiotics was able to prevent recurrence of infection in most patients, but higher than expected rates of acute kidney injury were observed in this study. Therefore, while intra-articular vancomycin therapy may have some effectiveness in treating recalcitrant prosthetic joint infections, its ability to eradicate all bacterial niduses is unproven, and clinicians should be cognizant of potential adverse events that can occur with this therapy.
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Affiliation(s)
- James B Doub
- Division of Infectious Diseases, University of Maryland School of Medicine, 725 West Lombard Street, BaltimoreMaryland, MD, 21201, USA.
| | - Emily L Heil
- Department of Pharmacy Practice and Science, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Theodore Manson
- Department of Orthopedic Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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2
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Becker K. Detection, Identification and Diagnostic Characterization of the Staphylococcal Small Colony-Variant (SCV) Phenotype. Antibiotics (Basel) 2023; 12:1446. [PMID: 37760742 PMCID: PMC10525764 DOI: 10.3390/antibiotics12091446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
While modern molecular methods have decisively accelerated and improved microbiological diagnostics, phenotypic variants still pose a challenge for their detection, identification and characterization. This particularly applies if they are unstable and hard to detect, which is the case for the small-colony-variant (SCV) phenotype formed by staphylococci. On solid agar media, staphylococcal SCVs are characterized by tiny colonies with deviant colony morphology. Their reduced growth rate and fundamental metabolic changes are the result of their adaptation to an intracellular lifestyle, regularly leading to specific auxotrophies, such as for menadione, hemin or thymidine. These alterations make SCVs difficult to recognize and render physiological, biochemical and other growth-based methods such as antimicrobial susceptibility testing unreliable or unusable. Therefore, diagnostic procedures require prolonged incubation times and, if possible, confirmation by molecular methods. A special approach is needed for auxotrophy testing. However, standardized protocols for SCV diagnostics are missing. If available, SCVs and their putative parental isolates should be genotyped to determine clonality. Since their detection has significant implications for the treatment of the infection, which is usually chronic and relapsing, SCV findings should be specifically reported, commented on, and managed in close collaboration with the microbiological laboratory and the involved clinicians.
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Affiliation(s)
- Karsten Becker
- Friedrich Loeffler-Institute of Medical Microbiology, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße 1, 17489 Greifswald, Germany
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3
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Tran NN, Morrisette T, Jorgensen SCJ, Orench-Benvenutti JM, Kebriaei R. Current therapies and challenges for the treatment of Staphylococcus aureus biofilm-related infections. Pharmacotherapy 2023; 43:816-832. [PMID: 37133439 DOI: 10.1002/phar.2806] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 05/04/2023]
Abstract
Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and contributes to significant increase in morbidity and mortality especially when associated with medical devices and in biofilm form. Biofilm structure provides a pathway for the enrichment of resistant and persistent phenotypes of S. aureus leading to relapse and recurrence of infection. Minimal diffusion of antibiotics inside biofilm structure leads to heterogeneity and distinct physiological activity. Additionally, horizontal gene transfer between cells in proximity adds to the challenges associated with eradication of biofilms. This narrative review focuses on biofilm-associated infections caused by S. aureus, the impact of environmental conditions on biofilm formation, interactions inside biofilm communities, and the clinical challenges that they present. Conclusively, potential solutions, novel treatment strategies, combination therapies, and reported alternatives are discussed.
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Affiliation(s)
- Nikki N Tran
- Department of Pharmacy, The Ohio State University Wexner Medical Center - The James Cancer Hospital and Solove Research Institute, Columbus, Ohio, USA
| | - Taylor Morrisette
- Department of Clinical Pharmacy and Outcomes Sciences, Medical University of South Carolina College of Pharmacy, Charleston, South Carolina, USA
- Department of Pharmacy Services, Medical University of South Carolina Shawn Jenkins Children's Hospital, Charleston, South Carolina, USA
| | - Sarah C J Jorgensen
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - José M Orench-Benvenutti
- P3 Research Laboratory, Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Razieh Kebriaei
- P3 Research Laboratory, Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
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4
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Zhou S, Rao Y, Li J, Huang Q, Rao X. Staphylococcus aureus small-colony variants: Formation, infection, and treatment. Microbiol Res 2022; 260:127040. [DOI: 10.1016/j.micres.2022.127040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 10/18/2022]
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5
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Min C, Wang H, Xia F, Tang M, Li J, Hu Y, Dou Q, Zou M. Characteristics of Staphylococcus aureus small colony variants isolated from wound specimen of a tertiary care hospital in China. J Clin Lab Anal 2021; 36:e24121. [PMID: 34837244 PMCID: PMC8761406 DOI: 10.1002/jcla.24121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/05/2021] [Accepted: 11/07/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Small colony variants (SCVs) of Staphylococcus aureus (S. aureus) frequently lead to chronic and recurrent infections, but they are always ignored and there are few researches on their clinical isolates. We intended to investigate the prevalence and characteristics of S. aureus SCVs. METHODS None-duplicated S. aureus strains isolated from wound samples were collected from January 2018 to December 2020. The characteristics (i.e. colony morphology, growth rate, coagulase, biofilm formation, and pathogenic characteristics), antimicrobial susceptibilities, and resistance mechanisms of SCVs were also investigated. The genetic background of SCVs was analyzed through staphylococcal protein A (SPA) typing, sequence typing, and pulse field gel electrophoresis (PFGE). RESULTS Three SCVs were screened from 278 S. aureus strains (1.1%). They formed pinpoint white colonies on blood agar plates with weak hemolysis. The reproduction speed in liquid medium was very slow for SCVs strains. The coagulase weakened or disappeared, and the ability to form biofilm varied greatly. Only slight inflammation was triggered when wound infected. The SPA typing was t2592, t233, and t023, and the sequence typing was ST88, ST239, and ST965, respectively. The PFGE revealed three SCVs were singletons. CONCLUSIONS The rate of SCVs in wound sample is low in our hospital, and the formation is associated with the usage of antimicrobial. SCVs grow slowly, and their colony morphology and biochemical characteristics are significantly different from classic S. aureus. SCVs may cause chronic infection and weak inflammation. SCVs form in resistant or susceptible strains, and there is no clonal epidemic in this hospital.
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Affiliation(s)
- Changhang Min
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Haichen Wang
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Fengjun Xia
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Mengli Tang
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Jun Li
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Yongmei Hu
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
| | - Qingya Dou
- Department of Infection Control CenterXiangya HospitalCentral South UniversityChangshaChina
| | - Mingxiang Zou
- Department of Clinical LaboratoryXiangya HospitalCentral South UniversityChangshaChina
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6
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A comprehensive review of bacterial osteomyelitis with emphasis on Staphylococcus aureus. Microb Pathog 2020; 148:104431. [PMID: 32801004 DOI: 10.1016/j.micpath.2020.104431] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 02/04/2023]
Abstract
Osteomyelitis, a significant infection of bone tissue, gives rise to two main groups of infection: acute and chronic. These groups are further categorized in terms of the duration of infection. Usually, children and adults are more susceptible to acute and chronic infections, respectively. The aforementioned groups of osteomyelitis share almost 80% of the corresponding bacterial pathogens. Among all bacteria, Staphylococcus aureus (S. aureus) is a significant pathogen and is associated with a high range of osteomyelitis symptoms. S. aureus has many strategies for interacting with host cells including Small Colony Variant (SCV), biofilm formation, and toxin secretion. In addition, it induces an inflammatory response and causes host cell death by apoptosis and necrosis. However, any possible step to take in this respect is dependent on the conditions and host responses. In the absence of any immune responses and antibiotics, bacteria actively duplicate themselves; however, in the presence of phagocytic cell and harassing conditions, they turn into a SCV, remaining sustainable for a long time. SCV is characterized by notable advantages such as (a) intracellular life that mediates a dam against immune cells and (b) low ATP production that mediates resistance against antibiotics.
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7
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Fleege C, Rauschmann M, Arabmotlagh M, Rickert M. Development and current use of local antibiotic carriers in spondylodiscitis : Pilot study on reduction of duration of systemic treatment. DER ORTHOPADE 2020; 49:714-723. [PMID: 32719918 DOI: 10.1007/s00132-020-03942-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND The current study situation regarding the duration of systemic antibiotic treatment for spondylodiscitis is inhomogeneous and varies between 4-12 weeks. Due to the many undesirable side effects the aim is to achieve complete healing without recurrence or hematogenous scatter within the shortest possible period of time. The present pilot study investigated whether the additional application of a local antibiotic carrier to the surgically treated intervertebral disc space can contribute to a further reduction of treatment duration. MATERIAL AND METHODS In the pilot study 20 patients with acute spondylodiscitis and indications for surgical intervention were included. Surgical treatment was carried out by dorsal instrumentation, radical debridement of the site of infection, and cage interposition in the affected disc space. The remaining disc space was filled with homologous cancellous bone and antibiotic-loaded calcium sulfate hydroxyapatite pellets. A classification into a long-term and a short-term antibiotic group was performed. Both groups initially received a 10-day parenteral antibiotic administration. This was followed by oral antibiotics for 2 or 12 weeks, depending on the group. During the 12-month follow-up inflammation parameters, the local infection situation as well as the bony fusion and antibiotic tolerance were regularly checked. RESULTS The average age of the patients was 66.7 ± 11.2 years. Intraoperative detection of pathogens was successful in 65%. In 60% the antibiotic carrier was loaded with gentamicin, in 40% with vancomycin. At follow-up, all patients except one in the short-term antibiotic group had inflammation parameters within the normal range after 3 months. In the long-term antibiosis group, two patients still showed elevated infection values after 3 months, otherwise the values were within the normal range. After 12 months a complete cure of the infection was achieved in all patients. Antibiotic treatment intolerance occurred in 10% of the short-term antibiotic group and in 50% of the long-term group. CONCLUSION The results of the present pilot study show that with the additional use of absorbable local antibiotic carriers in the surgical treatment of bacterial spondylodiscitis it is possible to shorten the duration of systemic antibiotic treatment to 3 weeks. This can reduce the side effects and incompatibility of treatment and still achieve similar healing results.
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Affiliation(s)
- C Fleege
- Orthopädische Universitätsklinik Friedrichsheim gGmbH, Marienburgstraße 2, 60528, Frankfurt am Main, Germany.
| | | | | | - M Rickert
- Orthopädische Universitätsklinik Friedrichsheim gGmbH, Marienburgstraße 2, 60528, Frankfurt am Main, Germany
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8
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El Shazely B, Yu G, Johnston PR, Rolff J. Resistance Evolution Against Antimicrobial Peptides in Staphylococcus aureus Alters Pharmacodynamics Beyond the MIC. Front Microbiol 2020; 11:103. [PMID: 32117132 PMCID: PMC7033599 DOI: 10.3389/fmicb.2020.00103] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/17/2020] [Indexed: 12/03/2022] Open
Abstract
Antimicrobial peptides (AMPs) have been proposed as a promising class of new antimicrobials partly because they are less susceptible to bacterial resistance evolution. This is possibly caused by their mode of action but also by their pharmacodynamic characteristics, which differ significantly from conventional antibiotics. Although pharmacodynamics of antibiotic resistant strains have been studied, such data are lacking for AMP resistant strains. Here, we investigated if the pharmacodynamics of the Gram-positive human pathogen Staphylococcous aureus evolve under antimicrobial peptide selection. Interestingly, the Hill coefficient (kappa κ) evolves together with the minimum inhibition concentration (MIC). Except for one genotype, strains harboring mutations in menF and atl, all mutants had higher kappa than the non-selected sensitive controls. Higher κ results in steeper pharmacodynamic curve and, importantly, in a narrower mutant selection window. S. aureus selected for resistance to melittin displayed cross resistant against pexiganan and had as steep pharmacodynamic curves (high κ) as pexiganan-selected lines. By contrast, the pexiganan-sensitive tenecin-selected lines displayed lower κ. Taken together, our data demonstrate that pharmacodynamic parameters are not fixed traits of particular drug/strain interactions but actually evolve under drug treatment. The contribution of factors such as κ and the maximum and minimum growth rates on the dynamics and probability of resistance evolution are open questions that require urgent attention.
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Affiliation(s)
- Baydaa El Shazely
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany.,Zoology Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Guozhi Yu
- College of Life Sciences, Sichuan Agricultural University, Ya'an, China
| | - Paul R Johnston
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research, Berlin, Germany.,Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Jens Rolff
- Evolutionary Biology, Institute for Biology, Free University of Berlin, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research, Berlin, Germany.,Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germany
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9
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Lenhard JR, Smith NM, Quach CD, Nguyen TQ, Doan LH, Chau J. Bacterial brothers in arms: cooperation of Staphylococcus aureus and Pseudomonas aeruginosa during antimicrobial exposure. J Antimicrob Chemother 2019; 74:2657-2665. [DOI: 10.1093/jac/dkz247] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 05/03/2019] [Accepted: 05/16/2019] [Indexed: 12/23/2022] Open
Abstract
Abstract
Objectives
The optimal selection of antibacterials during polymicrobial infections is poorly defined. The objective of the current investigation was to quantify the pharmacodynamics of relevant antimicrobials during co-culture of Pseudomonas aeruginosa with two separate Staphylococcus aureus phenotypes.
Methods
Time–kill experiments were conducted against co-cultures of the P. aeruginosa strain PA01 paired with either the normal phenotype (NP) MRSA isolate COL or the small colony variant phenotype (SCVP) MRSA isolate Ia48. The killing by levofloxacin, gentamicin, clindamycin, vancomycin and polymyxin B was evaluated to investigate drugs with activity against one or both pathogens. A Hill-type function and a mechanism-based model were used to describe bacterial killing.
Results
P. aeruginosa attenuated the activity of clindamycin against NP MRSA, with a reduction in the Emax (maximal killing) from 3.67 (95% CI 2.79–4.56) in monoculture to 1.86 (95% CI 1.35–2.37) during co-culture, whereas a significant protective effect was not observed for other antibacterials. The reduction in NP MRSA killing by clindamycin was described well by a mechanism-based model that generated a maximal killing rate constant of clindamycin against the susceptible NP MRSA subpopulation of 0.267 h−1 in monoculture and 0.0395 h−1 in the presence of P. aeruginosa. During exposure to gentamicin, P. aeruginosa was the dominant organism in co-culture experiments regardless of the drug concentration or S. aureus phenotype; however, the SCVP MRSA was able to dominate the joint population beginning at a levofloxacin concentration of 1.5 mg/L.
Conclusions
The anti-staphylococcal activity of clindamycin was attenuated by the presence of P. aeruginosa.
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Affiliation(s)
- Justin R Lenhard
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Nicholas M Smith
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA
- School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Christine D Quach
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Tuan Q Nguyen
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Linh H Doan
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Jeanette Chau
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
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Bacterial biofilm formation is variably inhibited by different formulations of antibiotic-loaded bone cement in vitro. Knee Surg Sports Traumatol Arthrosc 2019; 27:1943-1952. [PMID: 30370437 DOI: 10.1007/s00167-018-5230-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/17/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE The aim of the present study was to quantitatively assess biofilm growth on the surface of bone cements discs containing different antibiotics, including colistin and linezolid. Biofilms of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Staphylococcus epidermidis were grown on bone cement discs for 96 h. METHODS Biofilm amounts were measured by confocal laser microscopy using live/dead staining and dedicated software at different time intervals (48, 72, and 96 h). RESULTS Bone cement containing vancomycin was not effective at reducing MRSA biofilm formation 96 h following bacterial inoculation. At a comparable time interval, linezolid-, clindamycin-, and aminoglycoside-loaded cement was still active against this biofilm. At the 72- and 96-h observations, S. epidermidis biofilm was present only on tobramycin and gentamicin discs. P. aeruginosa biofilms were present on cement discs loaded with colistin at all time intervals starting from the 48-h observation, whereas no biofilms were detected on tobramycin or gentamicin discs. CONCLUSION Bone cements containing different antibiotics have variable and time-dependent windows of activity in inhibiting or reducing surface biofilm formation. The effectiveness of bone cement containing vancomycin against MRSA biofilm is questionable. The present study is clinically relevant, because it suggests that adding the right antibiotic to bone cement could be a promising approach to treat periprosthetic infections. Indeed, the antibiofilm activity of different antibiotic-loaded bone cements could be preoperatively assessed using the current methodology in two-stage exchange procedures.
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Argenson JN, Arndt M, Babis G, Battenberg A, Budhiparama N, Catani F, Chen F, de Beaubien B, Ebied A, Esposito S, Ferry C, Flores H, Giorgini A, Hansen E, Hernugrahanto KD, Hyonmin C, Kim TK, Koh IJ, Komnos G, Lausmann C, Loloi J, Lora-Tamayo J, Lumban-Gaol I, Mahyudin F, Mancheno-Losa M, Marculescu C, Marei S, Martin KE, Meshram P, Paprosky WG, Poultsides L, Saxena A, Schwechter E, Shah J, Shohat N, Sierra RJ, Soriano A, Stefánsdóttir A, Suleiman LI, Taylor A, Triantafyllopoulos GK, Utomo DN, Warren D, Whiteside L, Wouthuyzen-Bakker M, Yombi J, Zmistowski B. Hip and Knee Section, Treatment, Debridement and Retention of Implant: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019; 34:S399-S419. [PMID: 30348550 DOI: 10.1016/j.arth.2018.09.025] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Key Words
- acute periprosthetic joint infection (PJI)
- antibiotic combination
- antibiotic duration
- antibiotic therapy
- antibiotic treatment
- biofilm
- chronic obstructive pulmonary disease (COPD)), and C-reactive protein (CRP) >115 mg/L (C), rheumatoid arthritis (R), indication prosthesis (I), male (M), exchange of mobile components (E), age > 80 years (80) (CRIME80) scores
- chronic renal failure (K), liver cirrhosis (L), index surgery (I), cemented prosthesis (C), and C-reactive protein (CRP) >115 mg/L (KLIC) score
- contraindications
- debridement antibiotics and retention of the prosthesis
- debridement, antibiotics, implant retention (DAIR)
- emergency management
- exchange of modular components
- failed debridement, antibiotics, implant retention (DAIR) management
- fluoroquinolone
- gram-negative acute periprosthetic joint infection (PJI)
- indications
- infection recurrence
- intra-articular antibiotic infusion
- irrigation
- irrigation and debridement
- irrigation solution
- length of antibiotics
- megaprosthesis
- methicillin-resistant Staphylococcus aureus (MRSA)
- pathogen identification
- patient optimization
- periprosthetic joint infection (PJI) recurrence
- povidone-iodine
- rifampicin
- risk stratification
- surgical factors
- surgical intervention
- surgical outcome
- surgical outcomes
- surgical site infection (SSI) recurrence
- surgical timing
- treatment failure
- treatment success
- two-stage exchange arthroplasty
- unicompartmental knee arthroplasty debridement, antibiotics, implant retention (DAIR)
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12
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Zhao M, Bulman ZP, Lenhard JR, Satlin MJ, Kreiswirth BN, Walsh TJ, Marrocco A, Bergen PJ, Nation RL, Li J, Zhang J, Tsuji BT. Pharmacodynamics of colistin and fosfomycin: a 'treasure trove' combination combats KPC-producing Klebsiella pneumoniae. J Antimicrob Chemother 2017; 72:1985-1990. [PMID: 28444224 PMCID: PMC5890748 DOI: 10.1093/jac/dkx070] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 01/25/2017] [Accepted: 02/12/2017] [Indexed: 12/26/2022] Open
Abstract
Objectives KPC-producing Klebsiella pneumoniae are an emerging public health problem around the globe. We defined the combinatorial pharmacodynamics and ability to suppress resistance of two 'old' antibiotics, fosfomycin and colistin, in time-kill experiments and hollow-fibre infection models (HFIM). Methods Two KPC-2-producing K. pneumoniae isolates were used: one susceptible to both colistin and fosfomycin (KPC 9A: MIC colistin 0.25 mg/L and MIC fosfomycin ≤8 mg/L) and the other resistant to colistin and susceptible to fosfomycin (KPC 5A: MIC colistin 64 mg/L and MIC fosfomycin 32 mg/L). Time-kill experiments assessed an array of colistin and fosfomycin concentrations against both isolates. Colistin and fosfomycin pharmacokinetics from critically ill patients were simulated in the HFIM to define the pharmacodynamic activity of humanized regimens over 5 days against KPC 9A. Results In time-kill experiments, synergy was demonstrated for all colistin/fosfomycin combinations containing >8 mg/L fosfomycin against the double-susceptible KPC strain, 9A. Synergy versus KPC strain 5A was only achieved at the highest concentrations of colistin (4 mg/L) and fosfomycin (512 mg/L) at 48 h. In the HFIM, colistin or fosfomycin monotherapies resulted in rapid proliferation of resistant subpopulations; KPC 9A regrew by 24 h. In contrast to the monotherapies, the colistin/fosfomycin combination resulted in a rapid 6.15 log 10 cfu/mL reduction of KPC 9A by 6 h and complete suppression of resistant subpopulations until 120 h. Conclusions Colistin and fosfomycin may represent an important treatment option for KPC-producing K. pneumoniae otherwise resistant to traditional antibiotics.
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Affiliation(s)
- Miao Zhao
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
- Institute of Antibiotics, Huashan Hospital, Fudan University & Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai, China
| | - Zackery P. Bulman
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Justin R. Lenhard
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | | | | | - Thomas J. Walsh
- Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Amanda Marrocco
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Phillip J. Bergen
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Roger L. Nation
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Jian Li
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Jing Zhang
- Institute of Antibiotics, Huashan Hospital, Fudan University & Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai, China
| | - Brian T. Tsuji
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
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13
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Clinical Significance and Pathogenesis of Staphylococcal Small Colony Variants in Persistent Infections. Clin Microbiol Rev 2016; 29:401-27. [PMID: 26960941 DOI: 10.1128/cmr.00069-15] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype switch phenomenon, are presented. Moreover, relevant animal models and suggested treatment regimens, as well as the requirements for future research areas, are highlighted.
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Comparative pharmacodynamics of four different carbapenems in combination with polymyxin B against carbapenem-resistant Acinetobacter baumannii. Int J Antimicrob Agents 2016; 48:719-724. [PMID: 27773498 DOI: 10.1016/j.ijantimicag.2016.07.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 07/08/2016] [Accepted: 07/30/2016] [Indexed: 10/21/2022]
Abstract
The objective of this study was to determine the comparative pharmacodynamics of four different carbapenems in combination with polymyxin B (PMB) against carbapenem-resistant Acinetobacter baumannii isolates using time-kill experiments at two different inocula. Two A. baumannii strains (03-149-1 and N16870) with carbapenem minimum inhibitory concentrations (MICs) ranging from 8 to 64 mg/L were investigated in 48-h time-kill experiments using starting inocula of 106 CFU/mL and 108 CFU/mL. Concentration arrays of ertapenem, doripenem, meropenem and imipenem at 0.25×, 0.5×, 1×, 1.5× and 2× published maximum serum concentration (Cmax) values (Cmax concentrations of 12, 21, 48 and 60 mg/L, respectively) were investigated in the presence of 1.5 mg/L PMB. Use of carbapenems without PMB resulted in drastic re-growth. All carbapenem combinations were able to achieve a ≥3 log10 CFU/mL reduction by 4 h against both strains at 106 CFU/mL, whereas maximum reductions against strain 03-149-1 at 108 CFU/mL were 1.0, 3.2, 2.2 and 3.3 log10 CFU/mL for ertapenem, doripenem, meropenem and imipenem, respectively. None of the combinations were capable of reducing 108 CFU/mL of N16870 by ≥2 log10 CFU/mL. Ertapenem combinations consistently displayed the least activity, whereas doripenem, meropenem and imipenem combinations had similar activities that were poorly predicted by carbapenem MICs. As doripenem, meropenem, or imipenem displayed similar pharmacodyanmics in combination, the decision of which carbapenem to use in combination with PMB may be based on toxicodynamic profiles if drastic discordance in MICs is not present.
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15
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Lenhard JR, Bulitta JB, Connell TD, King-Lyons N, Landersdorfer CB, Cheah SE, Thamlikitkul V, Shin BS, Rao G, Holden PN, Walsh TJ, Forrest A, Nation RL, Li J, Tsuji BT. High-intensity meropenem combinations with polymyxin B: new strategies to overcome carbapenem resistance in Acinetobacter baumannii. J Antimicrob Chemother 2016; 72:153-165. [PMID: 27634916 DOI: 10.1093/jac/dkw355] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 07/07/2016] [Accepted: 07/26/2016] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The pharmacodynamics of polymyxin/carbapenem combinations against carbapenem-resistant Acinetobacter baumannii (CRAB) are largely unknown. Our objective was to determine whether intensified meropenem regimens in combination with polymyxin B enhance killing and resistance suppression of CRAB. METHODS Time-kill experiments for meropenem and polymyxin B combinations were conducted against three polymyxin B-susceptible (MIC of polymyxin B = 0.5 mg/L) CRAB strains with varying meropenem MICs (ATCC 19606, N16870 and 03-149-1; MIC of meropenem = 4, 16 and 64 mg/L, respectively) at 108 cfu/mL. A hollow-fibre infection model was then used to simulate humanized regimens of polymyxin B and meropenem (2, 4, 6 and 8 g prolonged infusions every 8 h) versus N16870 at 108 cfu/mL over 14 days. New mathematical mechanism-based models were developed using S-ADAPT. RESULTS Time-kill experiments were well described by the mathematical mechanism-based models, with the presence of polymyxin B drastically decreasing the meropenem concentration needed for half-maximal activity against meropenem-resistant populations from 438 to 82.1 (ATCC 19606), 158 to 93.6 (N16870) and 433 to 76.0 mg/L (03-149-1). The maximum killing effect of combination treatment was similar among all three strains despite divergent meropenem MIC values (Emax = 2.13, 2.08 and 2.15; MIC of meropenem = 4, 16 and 64 mg/L, respectively). Escalating the dose of meropenem in hollow-fibre combination regimens from 2 g every 8 h to 8 g every 8 h resulted in killing that progressed from a >2.5 log10 cfu/mL reduction with regrowth by 72 h (2 g every 8 h) to complete eradication by 336 h (8 g every 8 h). CONCLUSION Intensified meropenem dosing in combination with polymyxin B may offer a unique strategy to kill CRAB irrespective of the meropenem MIC.
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Affiliation(s)
- Justin R Lenhard
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA.,School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA.,California Northstate College of Pharmacy, Elk Grove, CA, USA
| | - Jürgen B Bulitta
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA.,Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, FL, USA
| | - Terry D Connell
- Department of Microbiology and Immunology and The Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Natalie King-Lyons
- Department of Microbiology and Immunology and The Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Cornelia B Landersdorfer
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Soon-Ee Cheah
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Visanu Thamlikitkul
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Gauri Rao
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA.,School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Patricia N Holden
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA.,School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Thomas J Walsh
- Departments of Pediatrics, Microbiology and Immunology Weill Cornell Medicine, New York, NY, USA
| | - Alan Forrest
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA.,School of Pharmacy, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, USA
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Brian T Tsuji
- Laboratory for Antimicrobial Dynamics, NYS Center of Excellence in Bioinformatics & Life Sciences, Buffalo, NY, USA .,School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY, USA
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16
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Kim NH, Kang YM, Han WD, Park KU, Park KH, Yoo JI, Lee DG, Park C, Song KH, Kim ES, Park SW, Kim NJ, Oh MD, Kim HB. Small-Colony Variants in Persistent and Recurrent Staphylococcus aureus Bacteremia. Microb Drug Resist 2016; 22:538-544. [PMID: 26982169 DOI: 10.1089/mdr.2015.0262] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The small-colony variant (SCV) phenotype of Staphylococcus aureus is associated with intracellular persistence and reduced antimicrobial susceptibility, which can lead to therapeutic failure. Since SCVs grow slowly and have a confusing morphology, the identification of infections due to SCV is difficult. We have identified SCVs in two patients who presented with persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia complicated by surgical site infections after cardiothoracic surgery. Nine blood isolates were collected from the two patients for species identification, antimicrobial susceptibility testing, and phenotypic and genotypic characterization. Colonies on Columbia blood agar were pinpoint, nonpigmented, nonhemolytic, and reverted to normal colonies after 48 hr of incubation on Schaedler agar. Auxotrophy assays revealed hemin dependence. Susceptibility to vancomycin (minimal inhibitory concentrations 1.0 μg/mL) was confirmed by E-test and broth microdilution test. All the isolates were identified as MRSA by multiplex polymerase chain reaction specific for the mecA, femA, and 16S rRNA genes, and all had the same genotype: Multilocus sequence typing ST5, SCCmec type II, agr type II, and spa type t2460. Moreover pulsed-field gel electrophoresis typing revealed that all nine isolates belonged to the same clone. Mutations in the relA gene were not found, and none of the isolates was identified as hVISA by population analysis profiling-AUC ratio. A high level of suspicion is required to detect SCVs, and although it is not common, the possibility of the SCV phenotype has to be considered in persistent S. aureus bacteremia.
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Affiliation(s)
- Nak-Hyun Kim
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Yu Min Kang
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Woong Dae Han
- 2 Division of Infectious Diseases, Seoul National University Bundang Hospital , Seongnam, Republic of Korea
| | - Kyoung Un Park
- 3 Department of Laboratory Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Kay-Hyun Park
- 4 Department of Thoracic Surgery, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Jae Il Yoo
- 5 Division of Antimicrobial Resistance, Center for Infectious Diseases, Korea National Institute of Health , Cheongwon, Republic of Korea
| | - Dong-Gun Lee
- 6 Vaccine Bio Research Institute, Catholic University of Korea , Seoul, Republic of Korea
| | - Chulmin Park
- 6 Vaccine Bio Research Institute, Catholic University of Korea , Seoul, Republic of Korea
| | - Kyoung-Ho Song
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea.,2 Division of Infectious Diseases, Seoul National University Bundang Hospital , Seongnam, Republic of Korea
| | - Eu Suk Kim
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea.,2 Division of Infectious Diseases, Seoul National University Bundang Hospital , Seongnam, Republic of Korea
| | - Sang Won Park
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Nam Joong Kim
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Myoung-Don Oh
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea
| | - Hong Bin Kim
- 1 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea.,2 Division of Infectious Diseases, Seoul National University Bundang Hospital , Seongnam, Republic of Korea
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Sequential Evolution of Vancomycin-Intermediate Resistance Alters Virulence in Staphylococcus aureus: Pharmacokinetic/Pharmacodynamic Targets for Vancomycin Exposure. Antimicrob Agents Chemother 2015; 60:1584-91. [PMID: 26711763 DOI: 10.1128/aac.02657-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/13/2015] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus possesses exceptional virulence and a remarkable ability to adapt in the face of antibiotic therapy. We examined the in vitro evolution of S. aureus in response to escalating vancomycin exposure by evaluating bacterial killing and the progression of resistance. A hollow-fiber infection model was utilized to simulate human doses of vancomycin increasing from 0.5 to 4 g every 12 h (q12h) versus a high inoculum (10(8) CFU/ml) of methicillin-resistant S. aureus (MRSA) USA300 and USA400. Host-pathogen interactions using Galleria mellonella and accessory gene regulator (agr) expression were studied in serially obtained isolates. In both USA300 and USA400 MRSA isolates, vancomycin exposure up to 2 g q12h resulted in persistence and regrowth, whereas 4 g administered q12h achieved sustained killing against both strains. As vancomycin exposure increased from 0.5 to 2 g q12h, the bacterial population shifted toward vancomycin-intermediate resistance, and collateral increases in the MICs of daptomycin and televancin were observed over 10 days. Guideline-recommended exposure of a ratio of the area under the concentration-time curve for the free, unbound fraction of the drug to the MIC (fAUC/MIC ratio) of 200 displayed a 0.344-log bacterial reduction in area, whereas fAUC/MICs of 371 and 554 were needed to achieve 1.00- and 2.00-log reductions in area, respectively. The stepwise increase in resistance paralleled a decrease in G. mellonella mortality (P = 0.021) and a gradual decline of RNAIII expression over 10 days. Currently recommended doses of vancomycin resulted in amplification of resistance and collateral damage to other antibiotics. Decreases in agr expression and virulence during therapy may be an adaptive mechanism of S. aureus persistence.
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A full genomic characterization of the development of a stable Small Colony Variant cell-type by a clinical Staphylococcus aureus strain. INFECTION GENETICS AND EVOLUTION 2015; 36:345-355. [PMID: 26458527 DOI: 10.1016/j.meegid.2015.10.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/07/2015] [Accepted: 10/08/2015] [Indexed: 12/30/2022]
Abstract
A key to persistent and recurrent Staphylococcus aureus infections is its ability to adapt to diverse and toxic conditions. This ability includes a switch into a biofilm or to the quasi-dormant Small Colony Variant (SCV). The development and molecular attributes of SCVs have been difficult to study due to their rapid reversion to their parental cell-type. We recently described the unique induction of a matrix-embedded and stable SCV cell-type in a clinical S. aureus strain (WCH-SK2) by growing the cells with limiting conditions for a prolonged timeframe. Here we further study their characteristics. They possessed an increased viability in the presence of antibiotics compared to their non-SCV form. Their stability implied that there had been genetic changes; we therefore determined both the genome sequence of WCH-SK2 and its stable SCV form at a single base resolution, employing Single Molecular Real-Time (SMRT) sequencing that enabled the methylome to also be determined. The genetic features of WCH-SK2 have been identified; the SCCmec type, the pathogenicity and genetic islands and virulence factors. The genetic changes that had occurred in the stable SCV form were identified; most notably being in MgrA, a global regulator, and RsbU, a phosphoserine phosphatase within the regulatory pathway of the sigma factor SigB. There was a shift in the methylomes of the non-SCV and stable SCV forms. We have also shown a similar induction of this cell-type in other S. aureus strains and performed a genetic comparison to these and other S. aureus genomes. We additionally map RNAseq data to the WCH-SK2 genome in a transcriptomic analysis of the parental, SCV and stable SCV cells. The results from this study represent the unique identification of a suite of epigenetic, genetic and transcriptional factors that are implicated in the switch in S. aureus to its persistent SCV form.
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19
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Johns BE, Purdy KJ, Tucker NP, Maddocks SE. Phenotypic and Genotypic Characteristics of Small Colony Variants and Their Role in Chronic Infection. Microbiol Insights 2015; 8:15-23. [PMID: 26448688 PMCID: PMC4581789 DOI: 10.4137/mbi.s25800] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/09/2015] [Accepted: 08/13/2015] [Indexed: 01/02/2023] Open
Abstract
Small colony variant (SCV) bacteria arise spontaneously within apparently homogeneous microbial populations, largely in response to environmental stresses, such as antimicrobial treatment. They display unique phenotypic characteristics conferred in part by heritable genetic changes. Characteristically slow growing, SCVs comprise a minor proportion of the population from which they arise but persist by virtue of their inherent resilience and host adaptability. Consequently, SCVs are problematic in chronic infection, where antimicrobial treatment is administered during the acute phase of infection but fails to eradicate SCVs, which remain within the host causing recurrent or chronic infection. This review discusses some of the phenotypic and genotypic changes that enable SCVs to successfully proliferate within the host environment as potential pathogens and strategies that could ameliorate the resolution of infection where SCVs are present.
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Affiliation(s)
- Benjamin E Johns
- Department of Biomedical Science, Cardiff School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Kevin J Purdy
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Nicholas P Tucker
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Sarah E Maddocks
- Department of Biomedical Science, Cardiff School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
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20
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Leimer N, Rachmühl C, Palheiros Marques M, Bahlmann AS, Furrer A, Eichenseher F, Seidl K, Matt U, Loessner MJ, Schuepbach RA, Zinkernagel AS. Nonstable Staphylococcus aureus Small-Colony Variants Are Induced by Low pH and Sensitized to Antimicrobial Therapy by Phagolysosomal Alkalinization. J Infect Dis 2015; 213:305-13. [PMID: 26188074 DOI: 10.1093/infdis/jiv388] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/01/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Staphylococcus aureus-infected patients treated with antibiotics that are effective in vitro often experience relapse of infection because the bacteria hide in privileged locations. These locations include abscesses and host cells, which contain low-pH compartments and are sites from which nonstable S. aureus small-colony variants (SCVs) are frequently recovered. METHODS We assessed the effect of low pH on S. aureus colony phenotype and bacterial growth, using in vitro and in vivo models of long-term infection. RESULTS We showed that low pH induced nonstable SCVs and nonreplicating persisters that are capable of regrowth. Within host cells, S. aureus was located in phagolysosomes, a low-pH compartment. Therapeutic neutralization of phagolysosomal pH with ammonium chloride, bafilomycin A1, or the antimalaria drug chloroquine reduced SCVs in infected host cells. In a systemic mouse infection model, treatment with chloroquine also reduced SCVs. CONCLUSIONS Our results show that the acidic environment favors formation of nonstable SCVs, which reflect the SCVs found in clinics. They also provide evidence that treatment with alkalinizing agents, together with antibiotics, may provide a novel translational strategy for eradicating persisting intracellular reservoirs of staphylococci. This approach may also be extended to other intracellular bacteria.
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Affiliation(s)
- Nadja Leimer
- Division of Infectious Diseases and Hospital Epidemiology
| | | | | | | | | | | | - Kati Seidl
- Division of Infectious Diseases and Hospital Epidemiology
| | - Ulrich Matt
- Division of Infectious Diseases and Hospital Epidemiology
| | | | - Reto A Schuepbach
- Division of Surgical Intensive Care, University Hospital Zurich, University of Zurich
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