Atovaquone, chloroquine, primaquine, quinine and tetracycline: antiproliferative effects of relevant antimalarials on Neospora caninum / Atovaquona, cloroquina, primaquina, quinino e tetraciclina: efeitos antiproliferativos de antimaláricos relevantes em Neospora caninum

Abstract Neospora caninum is an apicomplexan parasite that causes abortion in cattle, resulting in significant economic losses. There is no commercial treatment for neosporosis, and drug repositioning is a fast strategy to test possible candidates against N. caninum. In this article, we describe the effects of atovaquone, chloroquine, quinine, primaquine and tetracycline on N. caninum proliferation. The IC50 concentrations in N. caninum were compared to the current information based on previous studies for Plasmodium and Toxoplasma gondii, correlating to the described mechanisms of action of each tested drug. The inhibitory patterns indicate similarities and differences among N. caninum, Plasmodium and T. gondii. For example, atovaquone demonstrates high antiparasitic activity in all the analyzed models, while chloroquine does not inhibit N. caninum. On the other hand, tetracycline is effective against Plasmodium and N. caninum, despite its low activity in T. gondii models. The repurposing of antimalarial drugs in N. caninum is a fast and inexpensive way to develop novel formulations using well-established compounds.

Resumo Neospora caninum é um parasita Apicomplexa relacionado a abortos no gado bovino, que resultam em impactos econômicos. Não há tratamento comercial para neosporosis e o reposicionamento de drogas indica uma estratégia rápida para testar candidatos anti-N. caninum. Neste artigo, são descritos os efeitos da atovaquona, cloroquina, quinino, primaquine e tetraciclina na proliferação de N. caninum. As concentrações IC50 em N. caninum foram comparadas com a informação disponível, baseada em estudos publicados previamente para Plasmodium e Toxoplasma gondii, incluindo a correlação com os mecanismos de ação descritos para cada droga testada. Os padrões de inibição indicam pontos de similaridades e diferenças entre N. caninum, Plasmodium e T. gondii. Por exemplo, a atovaquona demonstra uma alta atividade antiparasitária em todos os modelos testados, enquanto a cloroquina não inibe N. caninum. Por outro lado, a tetraciclina é efetiva contra Plasmodium e N. caninum, em contraste com a baixa atividade em modelos de T. gondii. O reposicionamento de drogas antimaláricas em N. caninum é uma forma rápida e de baixo custo para o desenvolvimento de novas formulações que usam compostos bem estabelecidos.

Increasing Incidence of High-Level Tetracycline-Resistant Neisseria gonorrhoeae due to Clonal Spread and Foreign Import

PURPOSE: The detection of high-level tetracycline-resistant strains of Neisseria gonorrhoeae (TRNG) can make important epidemiological contributions that are relevant to controlling infections from this pathogen. In this study, we aimed to determine the incidence of TRNG isolates over time and also to investigate the characteristics and genetic epidemiology of these TRNG isolates in Korea. MATERIALS AND METHODS: The antimicrobial susceptibilities of 601 isolates of N. gonorrhoeae from 2004 to 2011 were tested by standard Clinical and Laboratory Standards Institute methods. To determine the molecular epidemiological relatedness, N. gonorrhoeae multi-antigen sequence typing was performed. RESULTS: The incidence of TRNG increased from 2% in 2004 to 21% in 2011. The minimum inhibitory concentration distributions of ceftriaxone and susceptibility of ciprofloxacin in TRNG were different from non-TRNG and varied according to the year of isolation. Most of the TRNG isolates collected from 2004 to 2007 exhibited genetic relatedness, with sequence type (ST) 1798 being the most common. From 2008 to 2011, the STs of the isolates became more variable and introduction of genetically unrelated TRNG were noted. CONCLUSION: The increased incidence of TRNG strains until 2007 appears to be due, at least in part, to clonal spread. However, we propose that the emergence of various STs since 2008 could be associated with foreign import.

Mecanismos moleculares de resistencia antibiótica en Escherichia coli asociadas a diarrea / Molecular mechanisms of antibiotic resistance in Escherichia coli- associated diarrhea

La resistencia antibiótica es un problema emergente a nivel mundial presente en diversas bacterias, en especial en la Escherichia coli, que tiene altos porcentajes de resistencia hacia ampicilina, trimetoprim-sulfametoxazol, tetraciclina, cloramfenicol y ácido nalidíxico, lo que supone grandes complicaciones en el tratamiento antibiótico cuando este es requerido. Este aumento de resistencia antibiótica se debe a la adquisición de diferentes mecanismos moleculares de resistencia mediante mutaciones puntuales a nivel cromosómico o transferencia horizontal de material genético entre especies relacionadas o diferentes, facilitada por algunos elementos genéticos tales como los integrones. Esta revisión discute los efectos de los mecanismos moleculares de resistencia más comunes en E.coli: inactivación enzimática, alteraciones en el sitio blanco y alteraciones de la permeabilidad. El conocer los mecanismos de resistencia implicados, como lo recomienda la Organización Mundial de la Salud, permitirá optimizar la vigilancia de resistencia y las políticas de control y uso de antibióticos a nivel nacional.

Antibiotic resistance is an emerging problem worldwide present in many bacteria, specially in Escherichia coli, which has high percentages of resistance to ampicilline, thrimethoprim-sulfamethoxazole, tetracycline, chloramphenicol and nalidixic acid, which implies important complications in antibiotic treatment when required. The increasing antibiotic resistance is due to the acquisition of different molecular mechanisms of resistance through point chromosomal mutations and /or horizontal transfer of genetic material between related or different species facilitated by some genetic elements such as integrons. This review discusses the effects of the most common molecular mechanisms of antibiotic resistance in E. coli: enzymatic inactivation, changes in the target site and permeability disturbances. Getting to know the mechanisms of resistance which are involved, as the World Health Organization recommends, will allow us to improve the surveillance of the antibiotic resistance, the control policies and the antibiotic utilization at a national level.

Effect of tetracycline on the bond performance of etch-and-rinse adhesives to dentin

This study evaluated the effect of modified tetracycline on the resin-dentin bond strength (µTBS), silver nitrate uptake (SNU) and solution homogeneity (SH) of two adhesives. Dentin surfaces were treated with phosphoric acid, rinsed off and either rewetted with water (control group - CO), 2 percent minocycline (MI), 2 percent doxycyline (DO) or 2 percent chlorhexidine (CH). Adhesive systems (Adper Single Bond 2 and Prime Bond NT) and composite were applied and light-polymerized. Specimens were sectioned to obtain bonded sticks (0.8 mm²) to test under tension at 0.5 mm/min. For SNU, specimens were immersed in silver nitrate and analyzed by EDX-SEM. SH was qualitatively analyzed after mixing the adhesives with different solvent-based solutions containing MI, DO and CH. Lower µTBS values were observed in the DO group compared with MI and CH (p = 0.01). Lower SNU was observed for MI and CH. The lowest µTBS for both adhesives was observed for the DO group (p = 0.01). Signs of phase separation were observed for DO with both adhesives. MI or CH used as rewetting solutions after acid etching did not affect the µTBS and hybrid layer quality.

Rates of antimicrobial resistance in latin america (2004-2007) and in vitro activity of the glycylcycline tigecycline and of other antibiotics

As a part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), Gram-positive and Gram-negative bacterial isolates were collected from 33 centers in Latin America (centers in Argentina, Brazil, Chile, Colombia, Guatemala, Honduras, Jamaica, Mexico, Panama, Puerto Rico, and Venezuela) from January 2004 to September 2007. Argentina and Mexico were the greatest contributors of isolates to this study. Susceptibilities were determined according to Clinical Laboratory Standards Institute guidelines. Resistance levels were high for most key organisms across Latin America: 48.3 percent of Staphylococcus aureus isolates were methicillin-resistant while 21.4 percent of Acinetobacter spp. isolates were imipenem-resistant. Extended-spectrum β-lactamase were reported in 36.7 percent of Klebsiella pneumoniae and 20.8 percent of E. coli isolates. Tigecycline was the most active agent against Gram-positive isolates. Tigecycline was also highly active against all Gram-negative organisms, with the exception of Pseuodomonas aeruginosa, against which piperacillin-tazobactam was the most active agent tested (79.3 percent of isolates susceptible). The in vitro activity of tigecycline against both Gram-positive and Gram-negative isolates indicates that it may be an useful tool for the treatment of nosocomial infections, even those caused by organisms that are resistant to other antibacterial agents.

Resistencia antimicrobiana en Helicobacter pylori: aspectos clínicos y moleculares / Antimicrobial resistance of Helicobacter pylori: clinical and molecular aspects

Helicobacter pylori is a relevant pathogen for gastroduodenal diseases in human beings. Although its eradication often improves gastroduodenal diseases, H pylori is acquiring an elevated rate of resistance to various antimicrobials, such as metronidazole, clarithromycin, tetracycline and amoxicillin. Multi-drug resistance is a major problem to select the appropriate treatment of infectious diseases. To improve our understanding on the com-plexity of the problem, in this article we review the resistance mechanisms and give an update on H pylori antimicrobial resistance (Rev Méd Chile 2003; 131: 1313-20).

Characterization of Neisseria gonorrhoeae strains isolated from patients with conjunctivitis

The conjunctivitis produced by Neisseria gonorrhoeae is the less frequently reported clinical form of gonococcal infection. We aim to phenotypically characterize N. gonorrhoeae isolated from conjunctivae sites. A total of six cases of this disease were notified in the Camagüey province, Cuba. All the strains isolated were penicillin-producing, showed the serogroup WI and exhibited the same antimicrobial susceptibility pattern and plasmid profile (2.6-3.2-24.5). The results contribute to the characterization of N. gonorrhoeae strains circulating in our environment

Antibióticos en el tratamiento periodontal: revisión bibliográfica / Antibiotics in periodontal treatment: review of the literature

Los antibióticos comparten, junto con otras drogas, determinantes farmacodinámicos y farmacocinéticos y, de igual forma, tienen a su vez determinantes únicos para cada uno de ellos, y de allí que varíen las concentraciones y los intervalos de dosis de ellos. Al estudiar los agentes antimicrobianos, observamos que tienen diferentes mecanismos de acción; por tal motivo, debemos conocer el microorganismo que vamos a atacar, ya que las diversas drogas varían en la forma de producir la muerte o inhibición del crecimiento bacteriano. En este artículo hacemos referencia a una breve reseña de la división de los antibióticos según el efecto que tengan sobre la bacteria, pasando por los parámetros utilizados para caracterizar este comportamiento, y luego, seguimos con una descripción de los antibióticos que se utilizan más frecuentemente como coadyuvantes en el tratamiento periodontal. De ellos sintetizamos sus características más relevantes, su actividad y las indicaciones que tienen en este campo, todo esto con el fin de utilizarlos correctamente en el momento debido

Infecciones periodontales: papel de los anaerobios estrictos, importancia de las B lactamasas, elección de un antibiótico (trans) / Periodontal infections: the role of anaerobic bacteria, the importance of B lactamases, antibiotic choice

El papel de los anaerobios estrictos y principalmente el de la Prevotella y de las Prophyromonas está perfectamente establecido en el curso de las patologías periodontales destructivas. La aparición durante los tratamientos de cepas resistentes a la tetraciclina, la acción insuficiente del metronidazol y de la clindamicina sobre las cepas que acompañan a los anaerobios (Eikenella, Actinobacilus), hacen que se vuelva hacia diversas asociaciones de antibióticos. Las penicilinas son activas si no las destruyen las B lactamasas producidas por numerosas especies bacterianas. Los inhibidores de B lactamasa asociados a las penicilinas hacen que esto tenga un gran interés. Así, el ácido clavulánico al bloquear las B lactamasas de los anaerobios y de cepas de Eikenella, debuelve a la amoxicilina su actividad inicial. Además, la acción intrínseca de los inhibidores sobre los anaerobios hace que la acción sea sinérgica incluso sobre especies no productoras de B lactamasa. Finalmente contribuyen a la obtención de un bactericida que actúe más precozmente

Las tetraciclinas en dermatología / Tetracyclins in dermatology

La amplitud de las indicaciones dermatológicas hacen a las tetraciclinas un grupo básico en esta especialidad. Comparte propiedades antimicrobianas, antiinflamatorias e inmunosupresoras entre otras, por lo que han sido usadas en el tratamiento de varios estados patológicos no infecciosos. Se hace una revisión de las enfermedades cutáneas que han sido tratadas con tetraciclinas y algunas propiedades que justifican su uso

Forme grave de fievre boutonneuse mediterraneenne: [a propos d'un cas]

The mediterranean exanthematous fever, a viral affection which its pathogen agent is the conori Rickettsia, can be complicated by the sever poly-visceral attacks, and can menace the vital prognosis. About one case with cutaneous, digestive, renal, haematologic, and encephalic attacks, we insist on the necessity of the diagnosis and a precocious treatement in taking charge of this affection

Tetracyclines, macrolides, licosamides & chloramphenicol

Los macrólidos, lincosaminas, tetraciclinas y cloramfenicol son antibióticos no relacionamento estructuralmente que comparten como mecanismo de acción la inhibición de la síntesis de proteínas. A pesar de sus diferencias individuales, se pueden clasificar como agentes de amplio espectro con uso en el manejo de una gran variedad de infecciones. A consecuencia de la similitud entre estos compuestos en cuanto a mecanismos de acción, el uso concurrente o en secuencia de los mismos debe ejercer-se con cautela. Dicha práctica podría resultar en antagonismo entre los agentes o en la inducción de resistencia bacteriana. Es importante, por tanto, entender la función de estos antibióticos y la interacciones potenciales que existen entre ellos. Se discuten las indicaciones, interacciones, mecanismos de acción, efectos adversos y contraindicaciones

Sensibilidade de Streptococcus agalactiae aos agentes antimicrobianos / Susceptibility of Streptococcus agalactiae to antimicrobial agents

A sensibilidade de Streptococcus agalactiae frente a 13 antimicrobianos foi verificada pelo teste da difusäo em ágar. As amostras testadas foram sensíveis a ampicilina, cefalotina, cefoxitina, clindamicina, cloranfenicol, eritromicina, lincomicina, penicilina, rifampicina e vancomicina, apresentando sensibilidade variável para a tetra ciclina e resistência a canamicina e tobramicina. Foram também determinadas, para as estirpes, as concentraçöes mínimas inibitórias (CMIs) pelo teste da diluiçäo em ágar para 6 antimicrobianos. Para a ampicilina, cefalotina, clindamicina, lincomicina e penicilina, as CMI50 e CMI90 apresentaram valores similares aos encontrados para a CMI. Para a eritromicina, a CMI90 (0,12 microng/ml) foi duas vezes maior que a CMI50

A marcaçäo do osso com substâncias fluorescentes / Bone labelling with fluorescent substances.

Discorre-se sobre a aplicaçäo do método de marcaçäo do osso com substâncias fluorescentes, enfatizando-se sua utilidade na pesquisa da neoformaçäo e remodelaçäo ósseas, principalmente quando se usa mais de um marcador. Em seguida, apresentam-se detalhes técnicos do processamento do material, com simplificaçöes que tornam o método mais acessível e rápido