Synergistic Combination of Antimicrobial Peptides and Cationic Polyitaconates in Multifunctional PLA Fibers.

Combining different antimicrobial agents has emerged as a promising strategy to enhance efficacy and address resistance evolution. In this study, we investigated the synergistic antimicrobial effect of a cationic biobased polymer and the antimicrobial peptide (AMP) temporin L, with the goal of developing multifunctional electrospun fibers for potential biomedical applications, particularly in wound dressing. A clickable polymer with pendent alkyne groups was synthesized by using a biobased itaconic acid building block. Subsequently, the polymer was functionalized through click chemistry with thiazolium groups derived from vitamin B1 (PTTIQ), as well as a combination of thiazolium and AMP temporin L, resulting in a conjugate polymer-peptide (PTTIQ-AMP). The individual and combined effects of the cationic PTTIQ, Temporin L, and PTTIQ-AMP were evaluated against Gram-positive and Gram-negative bacteria as well as Candida species. The results demonstrated that most combinations exhibited an indifferent effect, whereas the covalently conjugated PTTIQ-AMP displayed an antagonistic effect, potentially attributed to the aggregation process. Both antimicrobial compounds, PTTIQ and temporin L, were incorporated into poly(lactic acid) electrospun fibers using the supercritical solvent impregnation method. This approach yielded fibers with improved antibacterial performance, as a result of the potent activity exerted by the AMP and the nonleaching nature of the cationic polymer, thereby enhancing long-term effectiveness.

Real-life validation of a sample pooling strategy for screening of hepatitis C.

OBJECTIVES: To test a real-life sample pooling screening strategy which contributes to increasing the diagnostic capacity of clinical laboratories and expanding access to massive screening of hepatitis C. METHODS: After evaluating the sensitivity of the pooling strategy for seven different commercial assays which are used to determine the concentration of hepatitis C virus (HCV)-RNA in the plasma or serum, consecutive samples submitted for HCV diagnosis during the first 3 weeks of November 2021 were tested for HCV antibodies and, in parallel and in a blinded way, were pooled into 100 samples and tested for HCV-RNA. When the result was positive, a strategy to un-mask the positive(s) pool(s), which needed up to 15 total HCV-RNA tests, was used. RESULTS: All platforms were able to detect the presence of HCV-RNA in a single sample from a patient with viremic HCV present in pools of up to at least 10 000 HCV-RNA-free samples. A total of 1700 samples (17 pools) were analysed, with an overall prevalence of anti-HCV and HCV-RNA of 0.24%. After pooling, we could detect all samples previously detected using standard diagnosis tests (reflex testing) with a specificity and sensitivity of 100% (CI, 99.78-100%). Given the median current prices of anti-HCV and HCV-RNA on the market in Spain as well as personnel costs, testing using the pooling strategy would have resulted in a save of 3320€. CONCLUSIONS: Here, we demonstrated that by improving cost effectiveness, with no loss of sensitivity and specificity, the strategy of pooling samples may serve as an appropriate tool for use in large-scale screening of HCV.

Antibacterial Polymers Based on Poly(2-hydroxyethyl methacrylate) and Thiazolium Groups with Hydrolytically Labile Linkages Leading to Inactive and Low Cytotoxic Compounds.

Herein, we develop a well-defined antibacterial polymer based on poly(2-hydroxyethyl methacrylate) (PHEMA) and a derivative of vitamin B1, easily degradable into inactive and biocompatible compounds. Hence, thiazole moiety was attached to HEMA monomer through a carbonate pH-sensitive linkage and the resulting monomer was polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. N-alkylation reaction of the thiazole groups leads to cationic polymer with thiazolium groups. This polymer exhibits excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with an MIC value of 78 µg mL-1, whereas its degradation product, thiazolium small molecule, was found to be inactive. Hemotoxicity studies confirm the negligible cytotoxicity of the degradation product in comparison with the original antibacterial polymer. The degradation of the polymer at physiological pH was found to be progressive and slow, thus the cationic polymer is expected to maintain its antibacterial characteristics at physiological conditions for a relative long period of time before its degradation. This degradation minimizes antimicrobial pollution in the environment and side effects in the body after eradicating bacterial infection.

Antimicrobial Porous Surfaces Prepared by Breath Figures Approach.

Herein, efficient antimicrobial porous surfaces were prepared by breath figures approach from polymer solutions containing low content of block copolymers with high positive charge density. In brief, those block copolymers, which were used as additives, are composed of a polystyrene segment and a large antimicrobial block bearing flexible side chain with 1,3-thiazolium and 1,2,3-triazolium groups, PS54-b-PTTBM-M44, PS54-b-PTTBM-B44, having different alkyl groups, methyl or butyl, respectively. The antimicrobial block copolymers were blended with commercial polystyrene in very low proportions, from 3 to 9 wt %, and solubilized in THF. From these solutions, ordered porous films functionalized with antimicrobial cationic copolymers were fabricated, and the influence of alkylating agent and the amount of copolymer in the blend was investigated. Narrow pore size distribution was obtained for all the samples with pore diameters between 5 and 11 µm. The size of the pore decreased as the hydrophilicity of the system increased; thus, either as the content of copolymer was augmented in the blend or as the copolymers were quaternized with methyl iodide. The resulting porous polystyrene surfaces functionalized with low content of antimicrobial copolymers exhibited remarkable antibacterial efficiencies against Gram positive bacteria Staphylococcus aureus, and Candida parapsilosis fungi as microbial models.

Tailoring Macromolecular Structure of Cationic Polymers towards Efficient Contact Active Antimicrobial Surfaces.

The aim of this work is the preparation of contact active antimicrobial films by blending copolymers with quaternary ammonium salts and polyacrylonitrile as matrix material. A series of copolymers based on acrylonitrile and methacrylic monomers with quaternizable groups were designed with the purpose of investigating the influence of their chemical and structural characteristics on the antimicrobial activity of these surfaces. The biocide activity of these systems was studied against different microorganisms, such as the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Pseudomona aeruginosa and the yeast Candida parapsilosis. The results confirmed that parameters such as flexibility and polarity of the antimicrobial polymers immobilized on the surfaces strongly affect the efficiency against microorganisms. In contrast to the behavior of copolymers in water solution, when they are tethered to the surface, the active cationic groups are less accessible and then, the mobility of the side chain is critical for a good contact with the microorganism. Blend films composed of copolymers with high positive charge density and chain mobility present up to a more than 99.999% killing efficiency against the studied microorganisms.

Contact Active Antimicrobial Coatings Prepared by Polymer Blending.

Herein, contact active antimicrobial films are prepared by simply blending cationic amphiphilic block copolymers with commercial polystyrene (PS). The copolymers are prepared by combining atom transfer radical polymerization and "click chemistry." A variety of copolymers are synthesized, and composed of a PS segment and an antimicrobial block bearing flexible side chain with thiazole and triazole groups, 4-(1-(2-(4-methylthiazol-5-yl)ethyl)-1H-1,2,3-triazol-4-yl) butyl methacrylate (TTBM). The length of the TTBM block is varied as well as the alkylating agent. Different films are prepared from N,N-dimethylformamide solution, containing variable PS-b-PTTBM/PS ratio: from 0 to 100 wt%. Remarkably, the blend films, especially those with 30 and 50 wt% of copolymers, exhibit excellent antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi, even higher than films prepared exclusively from the cationic copolymers. Blends composed of 50 wt% of the copolymers present a more than 99.999% killing efficiency against the studied microorganisms. The better activity found in blends can be due to the higher roughness, which increases the surface area and consequently the contact with the microorganisms. These results demonstrate that the use of blends implies a reduction of the content of antimicrobial agent and also enhances the antimicrobial activity, providing new insights for the better designing of antimicrobial coatings.

Valoración de 2 técnicas automatizadas de microdilución frente a dilución en agar en la determinación de la sensibilidad a fosfomicina en cepas de Pseudomonas aeruginosa resistentes a carbapenémicos / Assessment of 2 automated microdilution techniques compared to an agar dilution method in determining sensitivity to fosfomycin in strains of carbapenem-resistant Pseudomonas aeruginosa

Los aislamientos de Pseudomonas aeruginosa resistentes a carbapenémicos se producen cada vez con más frecuencia, haciendo conveniente establecer tratamientos combinados de los que fosfomicina puede formar parte. Los criterios para establecer la sensibilidad de Pseudomonas aeruginosa a fosfomicina han sido aprobados utilizando un método de dilución en agar. Sin embargo, los sistemas de microdilución comercializados son los más utilizados en la práctica diaria. Los resultados de este estudio indican que estos métodos resultan aceptables cuando se quiera conocer el comportamiento de estos microorganismos frente a fosfomicina

Carbapenems-resistance in Pseudomonas aeruginosa isolates has been widely reported. Fosfomycin has been shown to act synergistically with other antimicrobials. The agar dilution method was approved for susceptibility testing for fosfomycin and Pseudomonas aeruginosa. However, broth microdilution methods are the basis of systems currently used in clinical microbiology laboratories. The results of this study indicate that these methods are acceptable as susceptibility testing methods for fosfomycin against these organisms

Antimicrobial films obtained from latex particles functionalized with quaternized block copolymers.

New amphiphilic block copolymers with antimicrobial properties were obtained by atom transfer radical polymerization (ATRP) and copper catalyzed cycloaddition following two approaches, a simultaneous strategy or a two-step synthesis, which were proven to be very effective methods. These copolymers were subsequently quaternized using two alkyl chains, methyl and butyl, to amplify their antimicrobial properties and to investigate the effect of alkyl length. Antimicrobial experiments in solution were performed with three types of bacteria, two gram-positive and one gram-negative, and a fungus. Those copolymers quaternized with methyl iodide showed better selectivities on gram-positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, against red blood cells, demonstrating the importance of the quaternizing agent chosen. Once the solution studies were performed, we prepared poly(butyl methacrylate) latex particles functionalized with the antimicrobial copolymers by emulsion polymerization of butyl methacrylate using such copolymers as surfactants. The characterization by various techniques served to test their effectiveness as surfactants. Finally, films were prepared from these emulsions, and their antimicrobial activity was studied against the gram-positive bacteria. The results indicate that the antimicrobial efficiency of the films depends not only on the copolymer activity but also on other factors such as the surface segregation of the antimicrobial agent to the interface.

Therapeutic drug monitoring of voriconazole helps to decrease the percentage of patients with off-target trough serum levels.

We monitored trough voriconazole serum concentrations from 107 patients (n = 258 samples) at 6 hospitals in Madrid. Most of the patients were male (67%) and had the following underlying conditions: hematological cancer (42%), solid organ transplantation (15%), chronic obstructive pulmonary disease (14%), human immunodeficiency virus infection (8.4%), solid cancer (5.6%), and other (29%). The indication for voriconazole administration was aspergillosis treatment (74.6%) and prophylaxis (14%). The main reasons for voriconazole trough drug monitoring were initiation of treatment/prophylaxis (33%), patient monitoring (47%), and suspected toxicity (3.5%). Levels (µg/ml) were subtherapeutic (<1; 18.2%), on-target (1-5.5; 71.3%), and high (>5.5; 10.5%). The samples percentage with on-target levels was significantly lower for the first sample than for subsequent samples (62.6% vs. 77.5%). "Subsequent samples," "admission in nonpediatric wards," "voriconazole used for treatment of invasive aspergillosis," and "use of proton pump inhibitors" were predictors of voriconazole therapeutic levels (≥1 µg/ml).

[Assessment of 2 automated microdilution techniques compared to an agar dilution method in determining sensitivity to fosfomycin in strains of carbapenem-resistant Pseudomonas aeruginosa]. / Valoración de 2 técnicas automatizadas de microdilución frente a dilución en agar en la determinación de la sensibilidad a fosfomicina en cepas de Pseudomonas aeruginosa resistentes a carbapenémicos.

Carbapenems-resistance in Pseudomonas aeruginosa isolates has been widely reported. Fosfomycin has been shown to act synergistically with other antimicrobials. The agar dilution method was approved for susceptibility testing for fosfomycin and Pseudomonas aeruginosa. However, broth microdilution methods are the basis of systems currently used in clinical microbiology laboratories. The results of this study indicate that these methods are acceptable as susceptibility testing methods for fosfomycin against these organisms.

Copolymers of acrylonitrile with quaternizable thiazole and triazole side-chain methacrylates as potent antimicrobial and hemocompatible systems.

A series of six copolymeric families, P(AN-co-MTAs) with various molar fractions of acrylonitrile (fAN) and methacrylates (fMTA) based on 1,3-thiazole and 1,2,3-triazole pendant groups with several spacers of different length and nature (alkyl or succinic), have been synthesized by conventional radical polymerization. The molar fraction of acrylonitrile in the copolymers (FAN) was determined by CHNS elemental analysis. The copolymers were also characterized by ATR-FTIR and molecular weights were determined by size exclusion chromatography (SEC). Due to the nucleophilic nature of the azole heterocycles the copolymers have been easily modified by N-alkylation reaction with butyl iodide leading to polyelectrolytes of diverse amphiphilic balance, P(AN-co-MTAs-BuI). The degree of quaternization (DQ) was quantitative in all instances and was determined by (1)H NMR spectroscopy. Dynamic light scattering (DLS) measurements were performed in order to determine the particle size and the charge density of the systems. The antimicrobial activity of the copolymers was studied in terms of minimal inhibitory concentration (MIC) against the Gram-positive bacteria Staphylococcus aureus, the Gram-negative Pseudomonas aeruginosa and the yeast Candida parapsilosis, as well as the cytotoxic activity toward human red blood cells (RBCs). These types of amphiphilic copolycations presented high selectivity (>300) maintaining moderate to good antimicrobial activity (MIC=4-64 µg/mL) and being non-hemolytic even at high molar fractions of AN in the copolymers compared to PMTAs-BuI homopolymers. Moreover, two examples of acrylonitrile-enriched copolymers (FAN=0.6) presented an excellent time-killing efficiency against microorganisms with 99.9% of killing ranging from 5 to 30 min. Besides, important changes in the morphology of the cell envelop of the microorganisms after treatment with P(AN-co-MTAs) were observed by Field Emission Scanning Electron Microscopy (FE-SEM) compared to untreated samples. These results indicate that these quaternized copolymers (QUATs) behave like the corresponding PMTAs-BuI homopolymers, being microbiostatic and also highly effective microbiocidal agents.

High Efficiency Antimicrobial Thiazolium and Triazolium Side-Chain Polymethacrylates Obtained by Controlled Alkylation of the Corresponding Azole Derivatives.

Two series of antimicrobial polymethacrylates (PMTAs) bearing mono and bis-cationic quaternary ammonium cations (QUATs) were prepared by controlled N-alkylation of 1,3-thiazole and 1,2,3-triazole pendant groups with butyl iodide (PMTAs-BuI). The degree of quaternization (DQ) of the azole heterocycles was monitored by (1)H NMR spectroscopy over a wide range of reaction times. Spectra analysis of the (1)H NMR aromatic region allowed to characterize and quantify the different species involved and, therefore, to control the chemical composition distribution of the amphiphilic polycations. The polymer charge density and the hydrodynamic sizes were measured by zeta potential and dynamic light scattering (DLS), respectively. Consequently, the relationship between structure and antibacterial properties and toxicity was studied. Interestingly, these polyelectrolytes present excellent selective toxicity against bacteria being nonhemolytic even at low values of DQ. Furthermore, they were also evaluated for their microbial time-killing efficiency, presenting a 3 log-reduction in only 15 min. Additionally, the bacteria cell morphology treated with PMTAs-BuI was analyzed.

Effect of glycounits on the antimicrobial properties and toxicity behavior of polymers based on quaternized DMAEMA.

Polymers with quaternary ammonium groups such as quaternized poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMAQ) have been used as antimicrobial agents because of their demonstrated good antimicrobial activities against a huge number and types of microbes, although their cytotoxicity is also well-known. In this work block copolymers based on PDMAEMAQ were synthesized containing hydrophobic segments of poly(butyl methacrylate) to improve the antimicrobial activity and glycomonomer units with the aim of decreasing the cytotoxicity of the polymers. Hydrophobic butyl methacrylate (BMA) blocks were chain extended by statistical and block copolymers of DMAEMA and 2-{[(d-glucosamin-2-N-yl)carbonylethyl methacrylate (HEMAGl) glycomonomer of different compositions. In order to find the balance between antimicrobial activity and cytotoxicity, the selectivity index of each polymer was obtained from minimum inhibitory concentrations (MIC) and white and red blood cells toxicity measurements.

Staphylococcus coagulasa negativos resistentes al linezolid: características fenotípicas, genotípicas y sensibilidad a combinaciones de antibióticos / Linezolid resistant coagulase-negative Staphylococcus: Phenotypical and genotypical characteristics and sensitivity to antibiotic combinations

Objetivo Recuperamos 22 aislados de estafilococos coagulasa negativos resistentes al linezolid de nuestro hospital para su identificación, sensibilidad, perfil epidemiológico, mecanismos de la resistencia al linezolid y posibles combinaciones antibióticas sinérgicas. Métodos La identificación de los aislados fue realizada mediante espectrometría de masas (Vitek-MS, BioMérieux). La sensibilidad se realizó con el sistema Vitek-2 (bioMérieux) y el método de microdilución en caldo según las recomendaciones del CLSI. Se realizó electroforesis en gel de campo pulsado (PFGE) para estudiar la relación genética de los aislados. Los mecanismos de la resistencia al linezolid fueron evaluados por PCR/secuenciación: presencia del gen cfr, mutaciones puntuales en el dominio V del ARN ribosomal 23S y mutaciones ribosomales adicionales (en los genes rplC, rplD y rplV). La actividad in vitro del linezolid fue estudiada por separado y en combinación con otros 3 antibióticos utilizando tiras de E-test. Resultados Veinte aislados fueron identificados como Staphylococcus epidermidis y 2 como Staphylococcus hominis. La PFGE demostró que los aislados pertenecían a diferentes clones: 21 de los aislados presentaron mutaciones en la región del dominio V del ARNr 23S y en el 54,5% fue encontrado el gen cfr. La administración previa de linezolid fue documentada en la mayor parte de casos. El linezolid en combinación con gentamicina mostró una actividad sinérgica en el 45,5% de los aislados. Conclusiones Staphylococcus epidermidis fue la especie de estafilococos coagulasa negativos resistentes al linezolid más frecuentes. Los valores de CMI fueron además elevados para otros antiestafilocócicos. Todas las cepas presentaron varios mecanismos de resistencia al linezolid. Nuestros datos sugieren que linezolid más gentamicina podría ser una combinación sinérgica frente a los estafilococos coagulasa negativos resistentes al linezolid(AU)

Objective We recovered 22 coagulase-negative staphylococci isolates in our hospital to study their identity, susceptibility, epidemiological profile, linezolid resistance mechanisms, and the possibilities of different antibiotic combinations. Methods Isolate identification was performed using mass spectrometry (Vitek-MS, bioMérieux). Susceptibility testing was carried out with the Vitek-2 system and the broth microdilution method according to CLSI guidelines. Pulsed-field gel electrophoresis (PFGE) was performed to analyze the genetic relationship between isolates. Linezolid resistance mechanisms were evaluated by PCR/sequencing: presence of cfr gene, point mutations in domain V of 23S ribosomal RNA and additional ribosomal mutations (in the rplC, rplD and rplV genes). The in vitro activity of linezolid was investigated alone and in combination with another three antibiotics acting on different cellular targets, using E-test strips. Results Twenty isolates were identified as Staphylococcus epidermidis, and 2 as Staphylococcus hominis. PFGE showed that isolates belonged to diverse clones, 21 of them presented mutations in the domain V region of 23S rRNA and the cfr gene was found in 54.5%. Prior administration of linezolid was documented in most of cases. Linezolid in combination with gentamicin showed a synergistic activity in 45.5% of isolates. Conclusions Staphylococcus epidermidis was the most prevalent linezolid-resistant coagulase-negative staphylococci. All isolates showed increased MIC values compared to other anti-staphylococcal drugs and several linezolid resistance mechanisms. Our data suggest that linezolid plus gentamicin could be a synergistic combination against linezolid-resistant coagulase-negative staphylococci(AU)

[Serological markers of Spanish and immigrant pregnant women in the south of Madrid during the period 2007-2010]. / Marcadores serológicos de gestantes españolas e inmigrantes en un área del sur de Madrid durante el periodo 2007-2010.

OBJECTIVE: The prevalence and evolution of the markers including in the serologic profile of pregnant woman was studied in our hospital during a period of 4 years. MATERIAL AND METHODS: A retrospective study of the prevalence of antibodies against Treponema pallidum, human immunodeficiency virus (HIV), Toxoplasma gondii, rubeola virus and hepatitis B virus (HBV), was performed in our hospital among Spanish and immigrant pregnant women, from January 2007 to December 2010. RESULTS: A total of 8,012 pregnant were studied, 2,752 (34.2%) of them were foreign. The non-treponemal tests (RPR) were positive in 40 (0.49%) women, being the prevalence slightly superior in foreigners than in natives (0.8 as opposed to 0.3%). The IgG anti-T. gondii global prevalence was 23,35% (1,874 patients). In Spanish pregnant this prevalence was 18%, and 33.8% in the immigrant women. Almost the total of Spanish pregnant (99.5%) displayed IgG antibodies against rubeola virus whereas in the foreigners this rate was 61.6%. The presence of HBsAg for HBV was tested in 86.6% of pregnant women (6,939/8,012), being positive the 0.75% (59 patients), with a prevalence in foreigners greater than in Spanish (1.65 as opposed to 0.4%). Antibodies anti-HVI were detected in 22 patients (0.22%), being the prevalence 0.15% among the Spanish and 0.51% among the foreigners.

Marcadores serológicos de gestantes españolas e inmigrantes en un área del sur de Madrid durante el periodo 2007-2010 / Serological markers of Spanish and immigrant pregnant women in the south of Madrid during the period 2007-2010

Objetivo. Conocer la prevalencia y evolución de los marcadores incluidos en el cribado serológico de la embarazada en nuestro hospital durante un periodo de 4 años. Material y métodos. Se realizó un estudio retrospectivo de la prevalencia de anticuerpos frente a Treponema pallidum, virus de la inmunodeficiencia humana (VIH), Toxoplasma gondii, virus de la rubéola y virus de la hepatitis B (VHB), en gestantes autóctonas y extranjeras que acudieron al Hospital de Móstoles o a alguno de los Centros de Salud que pertenecen a su área de influencia, en el periodo comprendido entre enero de 2007 y diciembre de 2010. Resultados. En el estudio se incluyeron 8.012 gestantes, 2.752 (34,2%) de las cuales eran extranjeras. Las pruebas no treponémicas (RPR) resultaron positivas en 40 (0,49%) pacientes, siendo la prevalencia ligeramente superior en extranjeras que en autóctonas (0,8 frente a 0,3%). La prevalencia global de IgG anti-T. gondii fue del 23,35% (1.874 pacientes). En gestantes españolas esta prevalencia se situó en el 18%, frente al 33,8% en las extranjeras. Prácticamente la totalidad de las gestantes españolas (99,5%) presentaban anticuerpos IgG frente al virus de la rubéola mientras que en las extranjeras esta tasa fue del 61,6%. Se determinó la presencia de HBsAg para VHB en el 86,6% de las gestantes (6.939/8.012), resultando positivas el 0,75% (59 pacientes), siendo la prevalencia en extrajeras mayor que en españolas (1,65 frente a 0,4%). Se detectaron anticuerpos anti-VIH en 22 pacientes (0,22%), siendo la prevalencia del 0,15% entre las españolas y del 0,51% en las extranjeras(AU)

Objective. The prevalence and evolution of the markers including in the serologic profile of pregnant woman wa studied in our hospital during a period of 4 years. Material and methods. A retrospective study of the prevalence of antibodies against Treponema pallidum, human immunodeficiency virus (HIV), Toxoplasma gondii, rubeola virus and hepatitis B virus (HBV), was performed in our hospital among Spanish and immigrant pregnant women, from January 2007 to December 2010. Results. A total of 8,012 pregnant were studied, 2,752 (34.2%) of them were foreign. The non-treponemal tests (RPR) were positive in 40 (0.49%) women, being the prevalence slightly superior in foreigners than in natives (0.8 as opposed to 0.3%). The IgG anti-T. gondii global prevalence was 23,35% (1,874 patients). In Spanish pregnant this prevalence was 18%, and 33.8% in the immigrant women. Almost the total of Spanish pregnant (99.5%) displayed IgG antibodies against rubeola virus whereas in the foreigners this rate was 61.6%. The presence of HBsAg for HBV was tested in 86.6% of pregnant women (6,939/8,012), being positive the 0.75% (59 patients), with a prevalence in foreigners greater than in Spanish (1.65 as opposed to 0.4%). Antibodies anti-HVI were detected in 22 patients (0.22%), being the prevalence 0.15% among the Spanish and 0.51% among the foreigners(AU)

[Linezolid resistant coagulase-negative Staphylococcus: phenotypical and genotypical characteristics and sensitivity to antibiotic combinations]. / Staphylococcus coagulasa negativos resistentes al linezolid: características fenotípicas, genotípicas y sensibilidad a combinaciones de antibióticos.

OBJECTIVE: We recovered 22 coagulase-negative staphylococci isolates in our hospital to study their identity, susceptibility, epidemiological profile, linezolid resistance mechanisms, and the possibilities of different antibiotic combinations. METHODS: Isolate identification was performed using mass spectrometry (Vitek-MS, bioMérieux). Susceptibility testing was carried out with the Vitek-2 system and the broth microdilution method according to CLSI guidelines. Pulsed-field gel electrophoresis (PFGE) was performed to analyze the genetic relationship between isolates. Linezolid resistance mechanisms were evaluated by PCR/sequencing: presence of cfr gene, point mutations in domain V of 23S ribosomal RNA and additional ribosomal mutations (in the rplC, rplD and rplV genes). The in vitro activity of linezolid was investigated alone and in combination with another three antibiotics acting on different cellular targets, using E-test strips. RESULTS: Twenty isolates were identified as Staphylococcus epidermidis, and 2 as Staphylococcus hominis. PFGE showed that isolates belonged to diverse clones, 21 of them presented mutations in the domain V region of 23S rRNA and the cfr gene was found in 54.5%. Prior administration of linezolid was documented in most of cases. Linezolid in combination with gentamicin showed a synergistic activity in 45.5% of isolates. CONCLUSIONS: Staphylococcus epidermidis was the most prevalent linezolid-resistant coagulase-negative staphylococci. All isolates showed increased MIC values compared to other anti-staphylococcal drugs and several linezolid resistance mechanisms. Our data suggest that linezolid plus gentamicin could be a synergistic combination against linezolid-resistant coagulase-negative staphylococci.

Comparative activities of daptomycin and several agents against staphylococcal blood isolates. Glycopeptide tolerance.

The activity of daptomycin was evaluated against 702 staphylococcal blood isolates (316 methicillin-susceptible Staphylococcus aureus, 187 methicillin-resistant S. aureus [MRSA], and 199 coagulase-negative staphylococci [CoNS]) collected in 41 Spanish hospitals. Glycopeptide tolerance and the incidence of heterogeneous glycopeptide-intermediate (hGISA) isolates were also examined. Vancomycin MICs determined by the Etest were compared with those obtained by the reference broth microdilution method. Daptomycin exhibited good activity, and only 2 isolates were nonsusceptible to this antibiotic. Resistance to linezolid was observed in 2 MRSA isolates and in 16 CoNS. The cfr gene was detected in 7 of these 18 isolates. Vancomycin and teicoplanin tolerance was 9.6% and 21.9%, respectively, in MRSA isolates. We detected the hGISA phenotype in 5.8% of MRSA isolates. Vancomycin MICs by the Etest were slightly higher than those obtained by broth microdilution. Daptomycin retained activity against isolates that were not susceptible to linezolid, teicoplanin, or quinupristin-dalfopristin.

[Methicillin-resistant Staphylococcus aureus: changes in the susceptibility pattern to daptomycin during a 10-year period (2001-2010)]. / Staphylococcus aureus resistente a meticilina: sensibilidad a la daptomicina a lo largo de un periodo de 10 años (2001-2010).

INTRODUCTION: The objective of this study was to evaluate the activity of daptomycin and other agents against methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from 2001 to 2010, in order to determine changes and to detect resistance trends. METHODS: The study included a total of 1,130 MRSA isolates collected as part of a multicenter surveillance program for antibiotic resistance, Estudio de Vigilancia de Resistencia a los Antimicrobianos (VIRA study), from 51 medical centers throughout Spain between 2001 and 2010. Broth microdilution test was performed according to the Clinical Laboratory Standards Institute guidelines. RESULTS: Daptomycin showed excellent activity and maintained its activity over time; only one MRSA isolate collected in 2001 was nonsusceptible to this agent (MIC=2 mg/L). Based on the MIC90, daptomycin was 2-4 dilutions more active than vancomycin, teicoplanin and linezolid. Daptomycin retained activity against MRSA isolates that were resistant to linezolid, to quinupristin-dalfopristin, or showed intermediate susceptibility to vancomycin. CONCLUSIONS: Our data and those of other studies, coupled with daptomycin's rapid bactericidal activity, suggest that this antimicrobial could be an alternative in the treatment of severe infections caused by multiresistant S. aureus.