Protein Antigens Increase the Protective Efficacy of a Capsule-Based Vaccine against Staphylococcus aureus in a Rat Model of Osteomyelitis

Staphylococcus aureus is an invasive bacterial pathogen, and antibiotic resistance has impeded adequate control of infections caused by this microbe. Moreover, efforts to prevent human infections with single-component S. aureus vaccines have failed. In this study, we evaluated the protective efficacy in rats of vaccines containing both S. aureus capsular polysaccharides (CPs) and proteins. The serotypes 5 CP (CP5) and 8 CP (CP8) were conjugated to tetanus toxoid and administered to rats alone or together with domain A of clumping factor A (ClfA) or genetically detoxified alpha-toxin (dHla). The vaccines were delivered according to a preventive or a therapeutic regimen, and their protective efficacy was evaluated in a rat model of osteomyelitis. Addition of dHla (but not ClfA) to the CP5 or CP8 vaccine induced reductions in bacterial load and bone morphological changes compared with immunization with either conjugate vaccine alone. Both the prophylactic and therapeutic regimens were protective. Immunization with dHla together with a pneumococcal conjugate vaccine used as a control did not reduce staphylococcal osteomyelitis. The emergence of unencapsulated or small-colony variants during infection was negligible and similar for all of the vaccine groups. In conclusion, addition of dHla to a CP5 or CP8 conjugate vaccine enhanced its efficacy against S. aureus osteomyelitis, indicating that the inclusion of multiple antigens will likely enhance the efficacy of vaccines against both chronic and acute forms of staphylococcal disease.Fil: Lattar, Santiago Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Noto Llana, Mariangeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Denoël, Philippe. GlaxoSmithKline Vaccines; BélgicaFil: Germain, Sophie. GlaxoSmithKline Vaccines; BélgicaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Lee, Jean C.. Harvard Medical School; Estados UnidosFil: Sordelli, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin

Rapid and reliable identification of Staphylococcus aureus capsular serotypes by means of artificial neural network-assisted Fourier-transform infrared spectroscopy

Staphylococcus aureus capsular polysaccharides (CP) are important virulence factors and represent putative targets for vaccine development. Therefore, the purpose of this study was to develop a high-throughput method to identify and discriminate the clinically important S. aureus capsular serotypes 5, 8, and NT (nontypeable). A comprehensive set of clinical isolates derived from different origins and control strains, representative for each serotype, were used to establish a CP typing system based on Fourier transform infrared (FTIR) spectroscopy and chemometric techniques. By combining FTIR spectroscopy with artificial neuronal network (ANN) analysis, a system was successfully established, allowing a rapid identification and discrimination of all three serotypes. The overall accuracy of the ANN-assisted FTIR spectroscopy CP typing system was 96.7% for the internal validation and 98.2% for the external validation. One isolate in the internal validation and one isolate in the external validation failed in the classification procedure, but none of the isolates was incorrectly classified. The present study demonstrates that ANN-assisted FTIR spectroscopy allows a rapid and reliable discrimination of S. aureus capsular serotypes. It is suitable for diagnostic as well as large-scale epidemiologic surveillance of S. aureus capsule expression and provides useful information with respect to chronicity of infection.Fil: Grunert, Tom. University of Veterinary Medicine; AustriaFil: Wenning, Mareike. Technische Universitat Munchen; AlemaniaFil: Barbagelata, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Fricker, Martina. University of Veterinary Medicine; AustriaFil: Sordelli, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Ehling Schulz, Monika. University of Veterinary Medicine; Austri

The anti MRSA biofilm activity of Thymus vulgaris essential oil in nanovesicles

Background: Thymus vulgaris essential oil (T) could be an alternative to classical antibiotics against bacterial biofilms, which show increased tolerance to antibiotics and host defence systems and contribute to the persistence of chronic bacterial infections. Hypothesis: A nanovesicular formulation of T may chemically protect the structure and relative composition of its multiple components, potentially improving its antibacterial and antibiofilm activity. Study design: We prepared and structurally characterized T in two types of nanovesicles: nanoliposomes (L80-T) made of Soybean phosphatidylcholine (SPC) and Polysorbate 80 (P80) [SPC:P80:T 1:0.75:0.3 w:w], and nanoarchaeosomes (A80-T) made of SPC, P80 and total polar archaeolipids (TPA) extracted from archaebacteria Halorubrum tebenquichense [SPC:TPA:P80:T 0.5:0.50.75:0.7 w:w]. We determined the macrophage cytotoxicity and the antibacterial activity against Staphylococcus aureus ATCC 25,923 and four MRSA clinical strains. Results: L80-T (Z potential −4.1 ± 0.6 mV, ∼ 115 nm, ∼ 22 mg/ml T) and A80-T (Z potential −6.6 ± 1.5 mV, ∼ 130 nm, ∼ 42 mg/ml T) were colloidally and chemically stable, maintaining size, PDI, Z potential and T concentration for at least 90 days. While MIC 90 of L80-T was > 4 mg/ml T, MIC 90 of A80-T was 2 mg/ml T for all S. aureus strains. The antibiofilm formation activity was maximal for A80-T, while L80-T did not inhibit biofilm formation compared to untreated control. A80-T significantly decreased the biomass of preformed biofilms of S. aureus ATCC 25,923 strain and of 3 of the 4 clinical MRSA isolates at 4 mg/ml T. It was found that the viability of J774A.1 macrophages was decreased significantly upon 24 h incubation with A80-T, L80-T and T emulsion at 0.4 mg/ml T. These results show that from 0.4 mg/ml T, a value lower than MIC 90 and the one displaying antibiofilm activity, with independence of its formulation, T significantly decreased the macrophages viability. Conclusion: Overall, because of its lower MIC 90 against planktonic bacteria, higher antibiofilm formation capacity and stability during storage, A80-T resulted better antibacterial agent than T emulsion and L80-T. These results open new avenues to explode the A80-T antimicrobial intracellular activity.Fil: Perez, Ana Paula. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Perez, Noelia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Suligoy Lozano, Carlos Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Altube, María Julia. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Farias, Marcelo Alexandre. No especifíca;Fil: Portugal, Rodrigo Villares. No especifíca;Fil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Morilla, María José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Romero, Eder Lilia. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Photodynamic inactivation of planktonic and biofilm growing bacteria mediated by a meso-substituted porphyrin bearing four basic amino groups

Biofilm-associated diseases account for 80% of all infections in humans. Due to the emergence of antibiotic resistances, alternative therapies such as Photodynamic Inactivation (PDI) of microorganisms have emerged. Porphyrins with intrinsic positive charges have been proposed as successful photosensitizers (PSs) against microorganisms. We have recently designed the new synthetic porphyrin 5,10,15,20-tetrakis[4-(3-N,N-dimethylammoniumpropoxy)phenyl]porphyrin (TAPP) containing four basic amine groups in the periphery of the tetrapyrrolic macrocycle, which can acquire positive charges at physiological pH, thus favouring the interaction with biomembranes. Illumination of planktonic cultures of Staphylococcus aureus at 180 J/cm2 in the presence of 2.5 μM TAPP induced complete bacteria eradication. For the TAPP-PDI treatment of S. aureus biofilms, higher light fluences and PS concentrations were needed. Employing 20 μM TAPP and 180 J/cm2, around 3-log CFU reduction were obtained. In order to determine the efficacy of TAPP-PDI on Gram-negative bacteria, we performed planktonic and biofilm assays employing Pseudomonas aeruginosa. Much higher TAPP doses as compared to S. aureus were needed to achieve planktonic bacteria photosensitization (3-log CFU reduction at 20 μM TAPP and 180 J/cm2). On the other hand, high concentrations of TAPP were nontoxic to P. aeruginosa growing on biofilms, and employing 30 μM TAPP and 180 J/cm2 we obtained 3-log CFU reduction. The main conclusion of the present work is that TAPP is a promising and efficient PS capable of promoting photodynamic killing of both Gram-negative and -positive in planktonic bacteria, though more effectively in the latter. In addition, TAPP-PDI induces similar photoinactivation rates in both bacteria types growing on biofilms, with lower dark toxicity in the Gram-negative one.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Photodynamic inactivation of planktonic and biofilm growing bacteria mediated by a meso-substituted porphyrin bearing four basic amino groups

Biofilm-associated diseases account for 80% of all infections in humans. Due to the emergence of antibiotic resistances, alternative therapies such as Photodynamic Inactivation (PDI) of microorganisms have emerged. Porphyrins with intrinsic positive charges have been proposed as successful photosensitizers (PSs) against microorganisms. We have recently designed the new synthetic porphyrin 5,10,15,20-tetrakis[4-(3-N,N-dimethylammoniumpropoxy)phenyl]porphyrin (TAPP) containing four basic amine groups in the periphery of the tetrapyrrolic macrocycle, which can acquire positive charges at physiological pH, thus favouring the interaction with biomembranes. Illumination of planktonic cultures of Staphylococcus aureus at 180 J/cm2 in the presence of 2.5 μM TAPP induced complete bacteria eradication. For the TAPP-PDI treatment of S. aureus biofilms, higher light fluences and PS concentrations were needed. Employing 20 μM TAPP and 180 J/cm2, around 3-log CFU reduction were obtained. In order to determine the efficacy of TAPP-PDI on Gram-negative bacteria, we performed planktonic and biofilm assays employing Pseudomonas aeruginosa. Much higher TAPP doses as compared to S. aureus were needed to achieve planktonic bacteria photosensitization (3-log CFU reduction at 20 μM TAPP and 180 J/cm2). On the other hand, high concentrations of TAPP were nontoxic to P. aeruginosa growing on biofilms, and employing 30 μM TAPP and 180 J/cm2 we obtained 3-log CFU reduction. The main conclusion of the present work is that TAPP is a promising and efficient PS capable of promoting photodynamic killing of both Gram-negative and -positive in planktonic bacteria, though more effectively in the latter. In addition, TAPP-PDI induces similar photoinactivation rates in both bacteria types growing on biofilms, with lower dark toxicity in the Gram-negative one.Fil: Mamone, Leandro Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Ferreyra, Darío David. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gándara, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Di Venosa, Gabriela Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Vallecorsa, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Saenz, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Calvo, Gustavo Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Batlle, Alcira María del C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casas, Adriana Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentin

Staphylococcus aureus adaptation to the host and persistence: Role of loss of capsular polysaccharide expression

A vast array of virulence factors enable Staphylococcus aureus to readily adapt to different environmental niches in diverse hosts. The cap gene cluster is present in almost all relevant clinical S. aureus isolates and capsular polysaccharide expression is apparent in isolates from patients with acute infection. The number of S. aureus isolates from patients with chronic infections that do not express capsular polysaccharide, however, is significantly high, indicating that loss of capsular polysaccharide expression may be a key S. aureus feature associated with persistence. The role of the loss of capsular polysaccharide expression as well as the emergence of other defined phenotypes and their relevance to persistence of S. aureus and chronicity of the infection is discussed in this article. © 2010 Future Medicine Ltd.Fil: Tuchscherr, Lorena Paola Nelly. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universitätsklinikum Münste; AlemaniaFil: Lffler, Bettina. Universitätsklinikum Münste; AlemaniaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Sordelli, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; Argentin

Sae regulator factor impairs the response to photodynamic inactivation mediated by Toluidine blue in Staphylococcus aureus

Photodynamic inactivation (PDI) involves the combined use of light and aphotosensitizer, which, in the presence of oxygen, originates cytotoxic species capableof inactivating bacteria. Since the emergence of multi-resistant bacterial strains isbecoming an increasing public health concern, PDI becomes an attractive choice.The aim of this work was to study the differential susceptibility to Toluidine blue (TB)mediated PDI (TB-PDI) of S. aureus mutants (RN6390 and Newman backgrounds) fordifferent key regulators of virulence factors related to some extent to oxidative stress.Complete bacteria eradication of planktonic cultures of RN6390 S. aureusphotosensitized with 13 μM TB was obtained upon illumination with a low light dose of4.2 J/cm2 from a non-coherent light source. Similarly, complete cell death was achievedapplying 1.3 μM TB and 19 J/cm2 light dose, showing that higher light doses can lead toequal cell death employing low photosensitizer concentrations. Interestingly, RN6390 inplanktonic culture responded significantly better to TB-PDI than the Newman strain.3We showed that deficiencies in rsbU, mgrA (transcription factors related to stressresponse) or agr (quorum sensing system involved in copper resistance to oxidativestress) did not modify the response of planktonic S. aureus to PDI. On the other hand,the two component system sae impaired the response to TB-PDI through a mechanismnot related to the Eap adhesin.More severe conditions were needed to inactivate S. aureus biofilms (0.5 mM TB, 157J/cm2 laser light). In mutant sae biofilms, strain dependant differential susceptibilitiesare not noticed.Fil: Gándara, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; ArgentinaFil: Mamone, Leandro Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; ArgentinaFil: Dotto, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Casas, Adriana Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentin

Enhancement of photodynamic inactivation of Staphylococcus aureus biofilms by disruptive strategies

Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers and visible light. On the one hand, near-infrared treatment (NIRT) has also bactericidal and dispersal effects on biofilms. In addition, dispersal biological tools such as enzymes have also been employed in antibiotic combination treatments. The aim of this work was to use alternative approaches to increase the PDI efficacy, employing combination therapies aimed at the partial disruption of the biofilms, thus potentially increasing photosensitizer or oxygen penetration and interaction with bacteria. To that end, we applied toluidine blue (TB)-PDI treatment to Staphylococcus aureus biofilms previously treated with NIRT or enzymes and investigated the outcome of the combined therapies. TB employed at 0.5 mM induced per se 2-log drop in S. aureus RN6390 biofilm viability. Each NIRT (980-nm laser) and PDI (635-nm laser) treatment induced a further reduction of 1-log of viable counts. The combination of successive 980- and 635-nm laser treatments on TB-treated biofilms induced additive effects, leading to a 4.5-log viable count decrease. Proteinase K treatment applied to S. aureus of the Newman strain induced an additive effect on PDI mortality, leading to an overall 4-log decrease in S. aureus viability. Confocal scanning laser microscopy after biofilm staining with a fluorescent viability test and scanning electron microscopy observations were correlated with colony counts. The NIRT dose employed (227 J/cm2) led to an increase from 21 to 47 °C in the buffer temperature of the biofilm system, and this NIRT dose also induced 100% keratinocyte death. Further work is needed to establish conditions under which biofilm dispersal occurs at lower NIRT doses.Fil: Gándara, Lautaro. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; ArgentinaFil: Mamone, Leandro Ariel. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; ArgentinaFil: Cervini Bohm, Gabriela Marta . Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Casas, Adriana Gabriela. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentin

Ciprofloxacin loaded o/w microemulsion against Staphylococcus aureus: Analytical and biological studies for topical and intranasal administration

An o/w microemulsion was designed and successfully loaded with the antibiotic ciprofloxacin for potentialtopical and intranasal use against Staphylococcus aureus. Based up on a physicochemical study an optimal systemcomposed of 2.50% of isopropyl myristate, 42% of polysorbate 80: ethyl alcohol (2:1), and 55% of water wasselected and then loaded with 0.30% of ciprofloxacin. The formulation presented a polydispersity index of(0.259 ± 0.021) and a particle size of (13.44 ± 0.24) nm. The pH value (5.32) was optimal for both topicaland intranasal uses. Besides, the formulation presented adequate osmolarity for instillation (341.9 mOsm L−1).The microemulsion stability over time and under different conditions was demonstrated. The permeation constantwas 2.73 × 10−4 cm h−1, a higher value compared with that of free ciprofloxacin (8.25 × 10−5 cm h−1).The antibacterial and antibiofilm activities were evaluated using the S. aureus Newman and MW2 strains in amurine model for testing the in vivo efficacy of the o/w formulation. It exhibited a minimal inhibition concentrationof 375 μg mL-1 and disrupted by 54% the previously formed biofilms. In conclusion, the new proposedciprofloxacin formulation caused a significant reduction of S. aureus nasal colonization and skin infection.Fil: Volpe, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Giacomodonato, Mónica Nancy. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Sordelli, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Insausti, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Grunhut, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin