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Javani S, Lorca R, Latorre A, Flors C, Cortajarena AL, Somoza Á. Antibacterial Activity of DNA-Stabilized Silver Nanoclusters Tuned by Oligonucleotide Sequence. ACS APPLIED MATERIALS & INTERFACES 2016; 8:10147-10154. [PMID: 27058628 DOI: 10.1021/acsami.6b00670] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Silver nanoclusters (AgNCs) stabilized by DNA are promising materials with tunable fluorescent properties, which have been employed in a plethora of sensing systems. In this report, we explore their antimicrobial properties in Gram-positive and Gram-negative bacteria. After testing 9 oligonucleotides with different sequence and length, we found that the antibacterial activity depends on the sequence of the oligonucleotide employed. The sequences tested yielded fluorescent AgNCs, which can be grouped in blue, yellow, and red emitters. Interestingly, blue emitters yielded poor antibacterial activity, whereas yellow and red emitters afforded an activity similar to silver nitrate. Furthermore, structural studies using circular dichroism indicate the formation of complexes with different stability and structure, which might be one of the factors that modulate their activity. Finally, we prepared a trimeric structure containing the sequence that afforded the best antimicrobial activity, which inhibited the growth of Gram-positive and negative bacteria in the submicromolar range.
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Affiliation(s)
- Siamak Javani
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
| | - Romina Lorca
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
| | - Alfonso Latorre
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
| | - Cristina Flors
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
| | - Aitziber L Cortajarena
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
| | - Álvaro Somoza
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC) , 28049 Madrid, Spain
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Odds FC. Should resistance to azole antifungals in vitro be interpreted as predicting clinical non-response? Drug Resist Updat 2007; 1:11-5. [PMID: 17092791 DOI: 10.1016/s1368-7646(98)80209-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Published data relating clinical treatment outcomes to susceptibility of Candida species in vitro for the triazole antifungal agents fluconazole and itraconazole show a clear association between rates of treatment failure and rising minimal inhibitory concentrations for the infecting fungal isolate. However, more than 50% of patients infected with an isolate 'resistant' to a triazole by NCCLS breakpoint criteria respond successfully to treatment with the triazole. Data for antibacterial agents similarly show that the association between resistance in vitro and treatment failure in vivo is far less than perfect. Susceptibility testing therefore falls into a category similar to that of weather forecasting. Despite good test standardization and sophisticated technology, the forecasts successfully predict trends, but cannot accurately foresee temperatures or levels of precipitation at a specific time in a specific location.
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Affiliation(s)
- F C Odds
- Department of Bacteriology and Mycology, Janssen Research Foundation, Beerse, Belgium.
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Miglioli PA, Cappellari G, Cavallaro A, Cardaioli C, Sossai P, Fille M, Allerberger F. Influence of Human Ascitic Fluid on the In VitroAntibacterial Activity of Moxifloxacin. J Chemother 2005; 17:401-3. [PMID: 16167519 DOI: 10.1179/joc.2005.17.4.401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We investigated the in vitro influence of HAF on the antibacterial activity of moxifloxacin against Escherichia coli ATCC 10798, Escherichia coli K-12, Proteus rettgeri (Sanelli), Staphylococcus aureus ATCC 25923, Staphylococcus aureus NCTC 1808 and Staphylococcus epidermidis ATCC 12228. Human ascitic fluid was obtained from 6 cirrhotic patients by paracentesis. The interaction effect was evaluated by the checkerboard technique. Our results indicate the ability of human ascitic fluid to reduce minimum inhibitory concentrations of moxifloxacin against Gram-negative bacteria, but not against Gram-positives.
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Affiliation(s)
- P A Miglioli
- Department of Pharmacology and Anaesthesiology, University of Padova, Italy.
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Mercier RC, Dietz RM, Mazzola JL, Bayer AS, Yeaman MR. Beneficial influence of platelets on antibiotic efficacy in an in vitro model of Staphylococcus aureus-induced endocarditis. Antimicrob Agents Chemother 2004; 48:2551-7. [PMID: 15215108 PMCID: PMC434186 DOI: 10.1128/aac.48.7.2551-2557.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelets contribute to antimicrobial host defense against infective endocarditis (IE) by releasing platelet microbicidal proteins (PMPs). We investigated the influence of thrombin-stimulated human platelets on the evolution of simulated IE in the presence and absence of vancomycin or nafcillin. Staphylococcus aureus strains differing in intrinsic susceptibility to PMPs or antibiotics were studied: ISP479C (thrombin-induced PMP-1 [tPMP-1] susceptible; nafcillin and vancomycin susceptible), ISP479R (tPMP-1 resistant; nafcillin and vancomycin susceptible), and GISA-NJ (tPMP-1 intermediate-susceptible; vancomycin intermediate-susceptible). Platelets were introduced and thrombin activated within the in vitro IE model 30 min prior to inoculation with S. aureus. At 0 to 24 h postinoculation, bacterial densities in chamber fluid and simulated endocardial vegetations (SEVs) were quantified and compared among groups. Activated platelets alone, or in combination with antibiotics, inhibited the proliferation of ISP479C in chamber fluid or SEVs over the initial 4-h period (P < 0.05 versus controls). Moreover, nafcillin-containing regimens exerted inhibitory effects beyond 4 h against ISP479C in both model phases. By comparison, activated platelets inhibited GISA-NJ proliferation in SEVs but not in chamber fluid. The combination of platelets plus nafcillin or vancomycin significantly inhibited proliferation of the GISA-NJ strain in SEVs compared to the effect of platelets or antibiotics alone (P < 0.05). In contrast, platelets did not significantly alter the antistaphylococcal efficacies of nafcillin or vancomycin against ISP479R. These data support our hypothesis that a beneficial antimicrobial effect may result from the interaction among platelets, PMPs, and anti-infective agents against antibiotic-susceptible or -resistant staphylococci that exhibit a tPMP-1-susceptible or -intermediate-susceptible phenotype.
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Affiliation(s)
- Renee-Claude Mercier
- College of Pharmacy MSC09 5360, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA.
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Ozgenel GY, Filiz G, Ozcan M. Effects of human amniotic fluid on cartilage regeneration from free perichondrial grafts in rabbits. ACTA ACUST UNITED AC 2004; 57:423-8. [PMID: 15191823 DOI: 10.1016/j.bjps.2003.12.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2003] [Accepted: 12/17/2003] [Indexed: 11/22/2022]
Abstract
After the chondrogenic potential of free grafts of perichondrium was shown in several experimental studies, perichondrium has been used to reconstruct cartilage tissue in various clinical situations. This study investigates the effects of human amniotic fluid on neochondrogenesis from free perichondrial grafts in a rabbit model. Since this fluid contains high concentrations of hyaluronic acid, hyaluronic acid-stimulating activator, growth factors, and extracellular matrix precursors during the second trimester, it may have a stimulating effect on neochondrogenesis. Perichondrial grafts, measuring 20 x 20 mm2 were obtained from the ears of 144 New Zealand young rabbits and were sutured over the paravertebral muscles. The rabbits were randomly divided into three groups with 48 rabbits per group. In group 1, 0.3 ml human amniotic fluid, and in group 2, 0.3 ml saline were injected underneath the perichondrial grafts. Group 3 formed the control group in which no treatment was given. Histologically, neochondrogenesis was evaluated in terms of cellular form and graft thickness at 2, 4, 6, and 8 weeks after surgery. In group 1, the mature cartilage was generated quickly and the cartilage plate in this group was significantly thick and extensive when compared with groups 2 and 3 at 8 weeks ( p<0.05 ANOVA). In conclusion, our study shows that human amniotic fluid enhances neochondrogenesis from free perichondrial grafts. The rich content of hyaluronic acid and growth factors possibly participate in this result.
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Affiliation(s)
- Güzin Yeşim Ozgenel
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Medical Faculty of Uludağ University, 16059 Görükle, Bursa, Turkey.
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Yeaman MR, Gank KD, Bayer AS, Brass EP. Synthetic peptides that exert antimicrobial activities in whole blood and blood-derived matrices. Antimicrob Agents Chemother 2002; 46:3883-91. [PMID: 12435692 PMCID: PMC132762 DOI: 10.1128/aac.46.12.3883-3891.2002] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptides that exert antimicrobial activity in artificial media may lack activity within blood or other complex biological matrices. To facilitate the evaluation of antimicrobial peptides for possible therapeutic utility, an ex vivo assay was developed to assess the extent and durability of peptide antimicrobial activities in complex fluid biomatrices of whole blood, plasma, and serum compared with those in conventional media. Novel antimicrobial peptides (RP-1 and RP-11) were designed based in part on platelet microbicidal proteins. RP-1, RP-11, or gentamicin was introduced into biomatrices either coincident with, or 2 h prior to, inoculation with an Escherichia coli target organism. Antimicrobial activities of peptides were assessed by quantitative culture 2 h after bacterial inoculation and compared to those of peptide-free and gentamicin controls. In whole blood and homologous plasma or serum, introduction of RP-1 or RP-11 coincident with E. coli was associated with a significant reduction in CFU per milliliter versus the respective peptide-free controls. Moreover, substantial antimicrobial activity remained when RP-1 or RP-11 was placed into whole blood or plasma 2 h prior to E. coli inoculation. These results suggest that the peptides were not rapidly inactivated within these biomatrices. Peptide antimicrobial activities were negatively affected by preincubation in serum or in heat-inactivated serum, compared with those of the respective controls. Peptides RP-1 and RP-11 were consistently effective at lower concentrations in biomatrices than in artificial media, indicating favorable antimicrobial interactions with components of blood or blood fractions. Collectively, these findings support the concept that synthetic peptides can be designed to exert potent antimicrobial activities in relevant and complex biological matrices.
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Affiliation(s)
- Michael R Yeaman
- Department of Medicine, Division of Infectious Diseases, Harbor-UCLA Medical Center, Research and Education Institute at Harbor-UCLA, Torrance, California 90502, USA.
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Ozgenel GY. The influence of human amniotic fluid on the potential of rabbit ear perichondrial flaps to form cartilage tissue. BRITISH JOURNAL OF PLASTIC SURGERY 2002; 55:246-50. [PMID: 12041980 DOI: 10.1054/bjps.2002.3811] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Since several experimental and clinical studies demonstrated the chondrogenic potential of perichondrium, there has been great interest in examining factors that might promote neochondrogenesis from perichondrium. Human amniotic fluid contains hyaluronic acid, growth factors and extracellular macromolecules, and may, therefore, have a stimulating effect on cartilage regeneration. This experimental study investigated the effect of human amniotic fluid on cartilage regeneration from rabbit ear perichondrial flaps, using 96 ears of 48 New Zealand young rabbits. A perichondrial flap was elevated and a cartilage defect measuring 20 mm x 15 mm was created on the dorsum of each ear, then the perichondrial flap was sutured in place. The ears were divided into two groups according to the solution injected underneath the perichondrial flap. The right ears, which were injected with 0.2 ml human amniotic fluid, formed the experimental group, and the left ears, which were injected with 0.2 ml saline, formed the control group. Macroscopic and histological progression of neochondrogenesis were evaluated at 2, 4, 6 and 8 weeks after surgery. Macroscopically, the cartilage in the experimental group was generated quickly and had a similar appearance to the surrounding cartilage tissue, whereas in the control group minimal cartilage formation was observed at 4 weeks. Histologically, the neocartilage was significantly thicker in the experimental group than in the control group at 8 weeks (P < 0.05, Student's t -test). It can be concluded that human amniotic fluid enhances new cartilage formation from rabbit ear perichondrial flaps. The preventive effect of human amniotic fluid on scar formation and the rich content of growth factors and extracellular matrix precursors may play a role in this result.
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Affiliation(s)
- G Y Ozgenel
- Department of Plastic and Reconstructive Surgery, Uludae University, Görükle, Bursa, Turkey
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Miglioli PA, Allerberger F, Walderberg I, Hasse J. Antibacterial activity of human pleural fluid: alone and in combination with antibiotics. Int J Antimicrob Agents 1998; 10:317-9. [PMID: 9916908 DOI: 10.1016/s0924-8579(98)00053-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study investigated the antibacterial activity of human pleural fluid (HPF) and its interaction with gentamicin (GM), meropenem (MRPM), ciprofloxacin (CPFX) and clarithromycin (CLTM) against Escherichia coli K-12, Proteus rettgeri (Sanelli) and Staphylococcus aureus. Minimal inhibitory concentrations or volumes, expressed as MIC or volume percentage (MIV, V/V%), were measured using a micro-dilution technique in microtiter plates. The antimicrobial activity of HPF combinations with antimicrobial drugs was evaluated by the chequerboard method calculating the fractional inhibitory concentration index (FIC) values. HPF MIVs (%) were: 37.54; 19.85; 1.74 for E. coli, P. rettgeri and S. aureus, respectively. FIC values indicated a synergistic effect with GM, MRPM and CPFX against E. coli and P. rettgeri and an additive effect for the combination HPF plus CLTM or indifference with HPF plus GM and CPFX against S. aureus. The presence of antibodies, complement factors, lysozyme, alpha-defensins and enzymes could explain the antimicrobial activity of HPF and its synergistic effect with certain antibiotics.
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Affiliation(s)
- P A Miglioli
- Department of Pharmacology, University of Padua, Padova, Italy.
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