Efetividade do metronidazol tópico e/ou sistêmico no controle do mau odor de tumores malignos fétidos: revisão sistemática / Effectiveness of topical and/or systemic metronidazole in the control of bad odor from fetid malignant tumors: systematic review

Introdução: Tumores fétidos são uma complicação devastadora do câncer e causam muito desconforto e isolamento para o paciente. Eles geralmente se desenvolvem nos últimos seis meses de vida e são muito difíceis de tratar com sucesso. O objetivo desta revisão sistemática foi analisar as evidências da efetividade do metronidazol tópico e/ou sistêmico no tratamento de mau odor em feridas tumorais malignas. Resultados: Foram encontrados inicialmente 62 artigos, e destes, apenas 4 artigos na íntegra contemplaram os critérios de inclusão. Dois deles foram ensaios clínicos, sendo 1 duplo-cego, randomizado e 1, não controlado de fase III. Um artigo foi retrospectivo com coleta de dados de 10 anos e 1 foi de coorte prospectivo. Destes, 3 analisaram a eficácia do tratamento de tumores malignos com mau odor com o uso de metronidazol tópico e apenas 1 comparou o uso de metronidazol tópico com sistêmico. Discussão: Um fator que contribui para o mau odor não ser controlado de forma adequada, diz respeito a falta de protocolos padronizados para tal. Ao longo dos anos, estudiosos no assunto, tentam encontrar intervenções acessíveis e eficazes para reduzir as graves recorrências do mau odor em feridas necróticas. Conclusão: Tanto a via tópica quanto à sistêmica demonstram ser eficazes no controle do mau odor. Os resultados desta revisão destacam a falta de pesquisa nesta área com pouca evidência para direcionar a prática clínica no tratamento dessas lesões. Outros estudos se fazem necessários, para se estabelecer protocolos mais efetivos no controle desta condição angustiante, vivenciada por alguns pacientes oncológicos.

Introduction: Fetid tumors are a devastating complica-tion of cancer and cause much discomfort and patient isolation. They usually develop themselves in the last six months of life and they are very difficult to be success-fully treated. The aim of this systematic review was to analyze the evidence on the effectiveness of topical and/or systemic metronidazole for the treatment of bad odor in malignant tumor wounds. Results: Sixty-two articles were initially found, and of these, only 4 articles met the inclusion criteria. Two of them were clinical trials, being 1 double-blind, randomized and 1 non-controlled phase III studies. One study was retrospective with a 10-years data collection period and 1 was a cohort prospective study. Of these, 3 analyzed the efficacy of treating malignant tumors with a bad odor using topical metronidazole and only 1 compared the use of topical and systemic metronidazole. Discussion: A factor that contributes to the bad odor not being properly controlled is the lack of standardized protocols. Over the years, studies have tried to find affordable and effective interventions to reduce serious recurrences of bad odor in necrotic wounds.Conclusion: Both topical and systemic routes have been shown to be effective in controlling bad odor. The results of this systematic review highlight the lack of research in this area with little evidence to guide clinical practice in the treatment of these injuries. Further studies are needed to establish more effective protocols to control this distressing condition, experienced by some cancer patients.

Cost-effectiveness of ceftolozane/tazobactam for the treatment of complicated intraabdominal and urinary tract infections in Colombia / Costo-efectividad de ceftolozano/tazobactam para el tratamiento de las infecciones intraabdominales e infecciones del tracto urinario complicadas en Colombia

Objective: To evaluate the cost-effectiveness of ceftolozane/tazobactam + metronidazole (C/T+M) and ceftolozane/tazobactam (C/T) compared with 8 alternatives used in the treatment of complicated intraabdominal infection (cIAI) and complicated urinary tract infection (cUTI) respectively. Methods: A Monte Carlo simulation decision model was used for the estimation and comparison of treatment-related costs, and quality adjusted life years for patients with cIAI treated with C/T+M in comparison with cefepime + metronidazole, ciprofloxacin + metronidazole, doripenem, levofloxacin + metronidazole, meropenem, piperacillin/tazobactam, ceftazidime + metronidazole or imipenem/cilastatin and patients with cUTI treated with C/T in comparison with cefepime, ciprofloxacin, doripenem, levofloxacin, meropenem, piperacillin/tazobactam, ceftazidime or imipenem/cilastatin. Local costs were estimated using base cases identified by experts and consulting local databases. Sensitivity values of the PACTS (Program to Assess Ceftolozane/Tazobactam Susceptibility) study in Latin America were used in the model. Results: C/T+M and C/T obtained incremental cost-effectiveness ratios (ICER) that were below the Colombian cost-effectiveness threshold (3 GDP per capita) in most comparisons, and were dominated by meropenem, considering only gram-negative microorganisms. Sensitivity assessments were also carried out, in which only the population with P. aeruginosa infections was considered, showing positive results for C/T+M and C/T (cost-effective or dominant with regards to all comparators). Conclusions: C/T+M and C/T could be cost-effective alternatives in the treatment of CIAI and CUTI in Colombia, when there is an adequate and rational use of antibiotics. The results of the sensitivity analyses showed dominance and cost-effectiveness with regards to every comparator in patients infected with P. aeruginosa

Objetivo: Evaluar la costo-efectividad de ceftolozano/tazobactam + metronidazol (C/T + M) y ceftolozano/tazobactam (C/T) en comparación con 8 alternativas utilizadas en el tratamiento de las infecciones intraabdominales complicadas (IAAc) e infecciones del tracto urinario complicadas (ITUc) respectivamente. Métodos: Se usó un modelo de decisión de simulación de Monte Carlo para la estimación y comparación de los costos relacionados con el tratamiento y los años de vida ajustados por calidad para pacientes con IAAc tratados con C/T + M, en comparación con cefepima + metronidazol, ciprofloxacina + metronidazol, doripenem , levofloxacina + metronidazol, meropenem, piperacilina / tazobactam, ceftazidima + metronidazol o imipenem/cilastatina, y pacientes con ITUc tratados con C/T en comparación con cefepime, ciprofloxacina, doripenem, levofloxacina, meropenem, piperacilina / tazobactam, ceftazidima o imipenem/cilastatina . Los costos locales se estimaron por medio de casos base identificados por expertos y consultando bases de datos locales. Se utilizaron los valores de sensibilidad bacteriana del estudio PACTS (Programa para evaluar la susceptibilidad al ceftolozano/tazobactam) en América Latina para poblar el modelo. Resultados: C/T + M y C/T obtuvieron razones de costo-efectividad incrementales (RCEI) que estaban por debajo del umbral de costo-efectividad colombiano (3 PIB per cápita) en la mayoría de las comparaciones, y fueron dominados por meropenem, considerando solo microorganismos gran-negativos También se llevaron a cabo análisis de sensibilidad, en los que solo se consideró la población con infecciones por P. aeruginosa, mostrando resultados positivos para C/T + M y C/T (costo efectivo o dominante con respecto a todos los comparadores). Conclusiones: C/T + M y C/T podrían ser alternativas costo efectivas en el tratamiento de IAAc e ITUc en Colombia, cuando existe un uso adecuado y racional de antibióticos. Los resultados de los análisis de sensibilidad mostraron dominio y costo-efectividad en relación con todos los comparadores en pacientes infectados con P. aeruginosa.

In vitro-induction of metronidazole-resistant Giardia duodenalis is not associated with nucleotide alterations in the genes involved in pro-drug activation

Giardiasis is an infectious disease caused by Giardia duodenalis. The pro-drug metronidazole (MTZ) is the first-line treatment for giardiasis. Parasite's proteins as pyruvate:ferredoxin oxidoreductase (PFOR), ferredoxin (Fd), nitroreductase-1 (NR-1) and thioredoxin reductase (TrxR) participate in MTZ activation. Here, we showed Giardia trophozoites long-term exposed to MTZ presented higher IC50 than controls, showing the drug influenced the parasite survival. That reduction in MTZ's susceptibility does not seem to be related to mutations in the genes pfor, fd, nr-1 or trxr. It points that different mechanism as alterations in other metabolic pathways can account for Giardia resistance to MTZ therapy.

Vigilância da resistência a antibióticos contra o Helicobacter pylori na região do Biobío (Chile) em uma década / Antibiotic resistance surveillance of helicobacter pylori at the biobío region (chile) in a decade

ABSTRACT BACKGROUND: Helicobacter pylori infection in Chile remains as a public and private health-care system's challenge, with a prevalence of the infection over 70%. Nowadays, antibiotic treatment of the infection is mandatory to prevent the arising of severe associated diseases but failures in the eradication therapy mainly due to clarithromycin resistance has been observed worldwide and first line eradication therapy seems to be not effective anymore in several geographical areas. Thus, health-care systems are committed to maintain an epidemiological surveillance upon the evolution of the antibiotic resistance of this priority 2 pathogen. OBJECTIVE: This work reports a 10 years surveillance of the primary antibiotic resistance of H. pylori clinical isolates at the Biobío region-Chile, and the evolution of resistance toward amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline among the species. METHODS: H. pylori strains were investigated during the periods 2005-2007 (1435 patients analysed) and 2015-2017 (220 patients analysed) by inoculating a saline homogenate biopsy onto the surface of Columbia agar (Oxoid, Basingstoke, UK) - supplemented with 7% horse red blood cells plus DENT inhibitor (Oxoid, Basingstoke, UK) - following by incubation at 37ºC under 10% CO2 atmosphere for five days. Antibiotic resistance pattern of the isolates was assessed using the disk diffusion test in Müeller-Hinton agar supplemented with 7% horse red blood cells followed by incubation for further three days under 10% CO2 atmosphere. Statistical analysis was done using the SPSS v22 software and P values <0.05 were considered statistically significant. RESULTS: A total of 41% of 1435 patients were detected to be infected with H. pylori by bacteriological culture in 2005-2007 period, meanwhile 32.7% from 220 patients were also infected in 2015-2017 period. The clinical isolates of H. pylori are mostly susceptible to amoxicillin and tetracycline (both over 98% of strains), but less susceptible to levofloxacin in both periods analysed (over 79% of the strains). On the other hand, metronidazole continuous showing the highest score of resistant isolates (over 40% of resistant strains), although an 18% fewer resistant strains were observed in 2015-2017 period. Clarithromycin, the key antibiotic in eradication therapies, has an increased frequency of resistant strain isolated in the decade (22.5% in 2005-2007 and 29.2% in 2015-2017). Multidrug resistant strains (two, three and four antibiotics) were also detected in both periods with the highest scores for simultaneous resistance to clarithromycin-metronidazole (18%) and clarithromycin-metronidazole-levofloxacin (12.5%) resistant strains. According to gender, the isolates resistant to amoxicillin, clarithromycin and metronidazole were more frequent in female, with a specific increment in amoxicillin and clarithromycin resistance. CONCLUSION: The frequency of clarithromycin resistance (29.2%) detected in 2015-2017 suggests that conventional triple therapy is no longer effective in this region.

RESUMO CONTEXTO: A infecção por Helicobacter pylori no Chile permanece como um desafio do sistema de saúde público e privado, com prevalência da infecção acima de 70%. Hoje em dia, o tratamento antibiótico da infecção é obrigatório para prevenir o surgimento de graves doenças associadas, mas falhas na terapia de erradicação, principalmente devido à resistência à claritromicina, têm sido observadas em todo o mundo, e a terapia de erradicação de primeira linha parece não ser mais eficaz em várias áreas geográficas. Assim, os sistemas de saúde estão comprometidos em manter uma vigilância epidemiológica sobre a evolução da resistência aos antibióticos deste patógeno prioritário tipo 2. OBJETIVO: Este trabalho relata uma vigilância de 10 anos da resistência antibiótica primária de isolados clínicos de H. pylori na região do Biobío-Chile, e a evolução da resistência em relação à amoxicilina, claritromicina, levofloxacina, metronidazol e tetraciclina entre as espécies. MÉTODOS: As cepas de H. pylori foram investigadas durante os períodos 2005-2007 (1435 pacientes analisados) e 2015-2017 (220 pacientes analisados) inoculando uma biópsia de homogeneizado fisiológico na superfície do agar Columbia (Oxoid, Basingstoke, Reino Unido) - suplementado com 7% de glóbulos vermelhos do cavalo mais o inibidor de DENTE (Oxoid, Basingstoke, Reino Unido) - seguindo pela incubação em 37ºC a atmosfera de 10% de CO2 por cinco dias. O padrão de resistência aos antibióticos dos isolados foi avaliado utilizando-se o teste de difusão em disco em agar Müeller-Hinton suplementado com 7% de glóbulos vermelhos de cavalo seguidos de incubação por mais três dias a atmosfera de 10% de CO2. A análise estatística foi realizada utilizando-se o software SPSS V22 e os valores de P<0,5 foram considerados estatisticamente significantes. RESULTADOS: Um total de 41% dos 1435 pacientes foram detectados como contaminados por H. pylori pela cultura bacteriológica no período 2005-2007, ao mesmo tempo 32,7% de 220 pacientes foram contaminados igualmente no período 2015-2017. Os isolados clínicos de H. pylori são principalmente suscetíveis à amoxicilina e tetraciclina (tanto mais de 98% das cepas), mas menos suscetíveis à levofloxacina em ambos os períodos analisados (mais de 79% das cepas). Por outro lado, o metronidazol permaneceu mostrando a maior pontuação de resistentes isolados (mais de 40% de cepas resistentes), embora tenham sido observados 18% menos cepas resistentes no período de 2015-2017. A claritromicina, o antibiótico-chave em terapias de erradicação, tem uma frequência aumentada de cepa resistente isolada na década (22,5% em 2005-2007 e 29,2% em 2015-2017). Cepas multirresistentes (dois, três e quatro antibióticos) também foram detectadas em ambos os períodos com os maiores escores de resistência simultânea à claritromicina-metronidazol (18%) e claritromicina-metronidazol-levofloxacina (12,5%) cepas resistentes. De acordo com o sexo, os isolados resistentes à amoxicilina, claritromicina e metronidazol foram mais frequentes no sexo feminino, com incremento específico em amoxicilina e resistência à claritromicina. CONCLUSÃO: A frequência de resistência à claritromicina (29,2%) detectada em 2015-2017 sugere que a terapia tripla convencional não é mais efetiva nesta região.

Helicobacter pylori: resistencia múltiple en pacientes de Bogotá, Colombia / Helicobacter pylori: Multiple resistance in patients from Bogotá, Colombia

Resumen Introducción. La resistencia a los antibióticos es la principal causa del fracaso del tratamiento contra Helicobacter pylori; la claritromicina y el metronidazol son los antibióticos que generan mayor resistencia. En Colombia, la resistencia primaria a estos dos antibióticos y el uso excesivo de levofloxacina han alcanzado los límites aceptados (13,6, 83 y 16 %, respectivamente). A pesar de ello, se usa el tratamiento empírico combinando estos antibióticos en pacientes en los que ha fallado anteriormente. Objetivo. Determinar la resistencia a los antibióticos en pacientes previamente tratados para H. pylori en Bogotá, Colombia. Materiales y métodos. Se llevó a cabo un estudio descriptivo en el que se evaluó mediante dilución en agar la resistencia a la amoxicilina, la claritromicina, la levofloxacina y el metronidazol en 10 aislamientos provenientes de 5 pacientes con tres o cuatro tratamientos fallidos para H. pylori. La resistencia a los antibióticos se confirmó mediante secuenciación de ADN (Magrogen, Korea). Resultados. Ocho de los aislamientos presentaron resistencia a dos o más antibióticos y todos fueron resistentes a la levofloxacina. Los patrones de sensibilidad de los aislamientos provenientes del antro pilórico y del cuerpo del estómago, fueron diferentes en tres de los pacientes. Conclusión. Hasta donde se sabe, esta es la primera evidencia de resistencia múltiple de H. pylori en Colombia en pacientes previamente tratados. Los resultados evidenciaron las consecuencias del uso de un esquema ineficaz de tratamiento antibiótico y la necesidad de evaluar la sensibilidad a los antibióticos en diferentes sitios anatómicos del estómago. La resistencia múltiple limita el número de antibióticos útiles para erradicar H. pylori.

Abstract Introduction: The main cause for Helicobacter pylori infection treatment failure is antibiotic resistance, where clarithromycin and metronidazole play the main role. In Colombia, primary resistance as a consequence of the use of these two antibiotics and excessive levofloxacin use is above the accepted limit (13.6%, 83%, and 16%, respectively). Despite this fact, empirical therapies that include the combination of these antibiotics are used in patients with previous therapeutic failure. Objective: To determine antibiotic resistance in patients previously treated for H. pylori in Bogotá, Colombia. Materials and methods: We conducted a descriptive study that included ten isolates obtained from five patients with three or four previous failed treatments for H. pylori. Antibiotic resistance to amoxicillin, clarithromycin, levofloxacin, and metronidazole was investigated by agar dilution and confirmed by DNA sequencing (Magrogen, Korea). Results: Eight isolates were resistant to two or more antibiotics. All isolates were resistant to levofloxacin. Susceptibility patterns in isolates from the gastric antrum and the body of the stomach were different in three patients. Conclusion: As far as we know, this is the first evidence of multiple H. pylori resistance in Colombia in previously treated patients. Results demonstrated the consequences of using an ineffective antibiotic scheme and the need to assess antibiotic susceptibility in different anatomical sites of the stomach. The consequences of multiple resistance decrease possible antibiotic effectiveness to eradicate H. pylori in the future.

Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells

Abstract Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls. Objective To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . Material and Methods APC cultures were kept in contact with CH or mTAP (250-1000 µg/mL) for 5 days, after which cell viability was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Next, APCs were subjected to CH or mTAP at 250 µg/mL for 5 days before inducing the differentiation assay. After 14 and 21 days, calcium deposition was assessed by the Alizarin Red S staining method, followed by elution and quantification using spectrophotometry. Data were analyzed using ANOVA followed by Tukey post hoc test. Results CH induced cell proliferation, whereas mTAP showed significant cytotoxicity at all concentrations tested. APC treated with CH demonstrated improved mineralization capacity at 14 days, while, for mTAP, significant reduction on the mineralization rate was observed for both experimental periods (14 and 21 days). Conclusion Our findings showed that CH induces cell proliferation and improves early mineralization, whereas mTAP was found cytotoxic and reduced the mineralization potential in vitro of APCs.

Frecuencia de mutaciones de la nitrorreductasa RdxA de Helicobacter pylori para la activación del metronidazol en una población del departamento del Cauca, Colombia / Frequency of Helicobacter pylori nitroreductase RdxA mutations for metronidazole activation in a population in the Cauca Department, Colombia

RESUMEN Introducción. La resistencia al metronidazol es un factor clave relacionado con el fracaso del tratamiento contra la infección por Helicobacter pylori asociada, principalmente, con mutaciones en la nitrorreductasa RdxA. A pesar de su importancia, los estudios sobre esta proteína son aún incipientes en Popayán, Colombia. Objetivo. Evaluar la frecuencia de las mutaciones en la nitrorreductasa RdxA en una población de pacientes con enfermedad gastrointestinal por H. pylori. Materiales y métodos. El ADN de 170 biopsias gástricas se amplificó mediante reacción en cadena de la polimerasa (PCR) para detectar las mutaciones en la nitrorreductasa RdxA. Se analizaron las secuencias traducidas a aminoácidos y se compararon con la cepa de referencia 26695. Resultados. La frecuencia de mutaciones de la nitrorreductasa RdxA en la población de estudio fue de 78 %. Su distribución más frecuente se detectó en las posiciones D59N (en 153 muestras), R131K (en 101 muestras), R90K (en 97 muestras), A118T (en 42 muestras), I160F (en 32 muestras), H97T (en 26 muestras) y en los codones de parada Q50*; D59*; E75*; C159* y I160* en cinco, una, tres, diez y seis muestras, respectivamente. El genotipo de virulencia más frecuente fue el vacAs1/m1 negativo para cagA (48,6 %). Conclusiones. La gran frecuencia de mutaciones en la nitrorreductasa RdxA en aislamientos de H. pylori en Popayán sugiere que los tratamientos empíricos con metronidazol no serían una opción válida para su erradicación en pacientes de la población estudiada.

ABSTRACT Introduction: Resistance to metronidazole is a key factor associated with Helicobacter pylori treatment failure. Even though resistance is mostly associated with RdxA nitroreductase mutations, studies of this H. pylori protein in Popayán (Colombia) are still incipient. Objective: To evaluate the frequency of mutations in the RdxA nitroreductase in a population of patients with H. pylori-positive gastrointestinal disease. Materials and methods: We amplified the DNA of 170 gastric biopsies by PCR to detect mutations in the RdxA nitroreductase. An analysis of DNA sequences translated into amino acid sequences was done and then compared to the reference strain 26695. Results: The frequency of RdxA nitroreductase mutations in this study population was 78%. Its most frequent distribution was found in positions D59N (153 samples), R131K (101 samples), R90K (97 samples), A118T (42 samples), I160F (32 samples) and H97T (26 samples), and meaningful stop codons Q50*, D59*; E75*, C159* and I160* in five, one, three, ten and six samples, respectively. The most common virulence genotype was vacAs1/m1 cagA negative (48.6 %). Conclusions: The high frequency of RdxA nitroreductase mutations in H. pylori isolates in Popayán (Colombia) indicates that empirical therapy with metronidazole may not be a valid option for the eradication of H. pylori in patients of the studied population.

Sensibilidad a los antimicrobianos de aislamientos de Helicobacter pylori aislados de lesiones gástricas / Antimicrobial susceptibility of Helicobacter pylori strains isolated from gastric lesions

Se evaluó la sensibilidad a los antimicrobianos de 30 aislamientos de Helicobacter pylori aislados de biopsias gástricas mediante los métodos de difusión por discos y tiras de E-test. Los antimicrobianos evaluados fueron amoxicilina, claritromicina, metronidazol y ciprofloxacina. No se encontraron cepas resistentes a amoxicilina, el 17% (5/30) fueron resistentes a claritromicina, el 20% (6/30) a ciprofloxacina por ambos métodos, y el 37% (11/30) a metronidazol por E-test. Si bien el número de cepas estudiadas fue reducido, hubo una sola discrepancia en la interpretación de la sensibilidad cuando se compararon ambos métodos: el metronidazol fue categorizado como sensible por E-test e intermedio por el método de difusión por discos. No pudo determinarse una asociación estadísticamente significativa entre el tipo de lesión histológica y el patrón de resistencia encontrado.

Antimicrobial susceptibility was evaluated by two diffusion methods: E-test strips to determine minimum inhibitory concentration (MIC) and disk diffusion for amoxicillin, clarithromycin, metronidazole and ciprofloxacin in 30 Helicobacter pylori strains isolated from gastric biopsies. No strains were resistant to amoxicillin, 17% (5/30) were resistant to clarithromycin, 20% (6/30) ciprofloxacin by both methods, and 37% (11/30) to metronidazole by the E-test. Although the number of strains studied was reduced, there was a single mismatch in interpreting susceptibility when both methods were compared; the same mismatch was observed for metronidazole, being categorized as sensitive by the E-test and as intermediate by disk diffusion. No association between the histological type of lesion and the resistance pattern found could be determined.

Efecto del metronidazol suplementado con hidroquinona en la adherencia de Lactobacillus acidophilus en células vaginales ovinas / Effect of metronidazole supplemented with hydroquinone on the adhesion of Lactobacillus acidophilus in ovine vaginal cells

This work demonstrates that the addition of metronidazole together with a ubiquitous quinone compound reduces adherence of Lactobacillus acidophilus to ovine vaginal cells. Spectrophotometric and voltammetric studies have shown that neoformed compounds were observed in these systems; there were also changes in their electroactive composition, and the oxidant status had a significantly higher value compared to the control (p < 0.05). Based on reduction potential (E; mV), the distribution of electroactive compound concentrations suggests that the compounds with low reduction potential induce this behavior, which would indicate that the addition of metronidazole with a ubiquitous quinone compound to the vaginal system might increase the reductive capacity of these systems. This work shows that the study of behavior and fluctuations of the redox compounds that compose the vaginal environment, in terms of concentration and species of redox molecules, must be hierarchized in order to better understand the early stages of colonization by microorganisms.

Este trabajo demuestra que la incorporación de metronidazol conjuntamente con un compuesto quinónico ubicuo disminuye la adherencia de Lactobacillus acidophilus a células vaginales ovinas. Los estudios espectrofotométricos y voltamétricos mostraron que en estos sistemas aparecieron compuestos neoformados y que hubo modificaciones en la composición electroactiva; asimismo, el estatus oxidante presentó un valor significativamente superior con respecto al control (p < 0,05). Según los potenciales de reducción (E; mV), la distribución de las concentraciones de los compuestos electroactivos muestra que los compuestos con bajos potenciales de reducción inducen este comportamiento. Esto indicaría que la incorporación de esta mezcla al sistema vaginal aumentaría su capacidad reductora. El trabajo muestra que el estudio del comportamiento y las fluctuaciones de los compuestos redox que componen el ambiente vaginal, en términos de concentración y especies moleculares, debe ser jerarquizado para comprender mejor las primeras etapas de la colonización de este ambiente por parte de los microorganismos.

Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion

Abstract Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2 μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125 μg/mL for both antimicrobials. The MIC90 were 4 μg/mL and 2 μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.

Susceptibilidad antimicrobiana de microorganismos anaerobios aislados de infecciones endodónticas primarias a amoxicilina y metronidazol y su asociación con los parámetros clínicos: serie de casos / Antimicrobial susceptibility of anaerobic microorganisms isolated from primary endodontic infections to amoxicillin and metronidazole and its association with clinical parameters: case series

El objetivo de este estudio es describir la composición de la microbiota anaerobia estricta/aerotolerante en infecciones endodónticas primarias, su susceptibilidad antimicrobiana, y la asociación con los parámetros clínicos. Se tomaron muestras de siete pacientes con necrosis pulpar sintomática o asintomática. Se utilizaron técnicas para la conservación, cultivo, incubación e identificación de anaerobios estrictos/aerotolerantes. Para determinar la susceptibilidad antimicrobiana a amoxicilina y metronidazol, se utilizó el método de dilución en agar. Se aislaron un total de 32 cepas, 20 (62,5 %) fueron anaerobios estrictos/aerotolerantes, y 8 (25 %) anaerobios facultativos. El microorganismo anaerobio estricto/aerotolerante más frecuente fue Fusobacterium nucleatum, se aisló en tres casos, todos relacionados con algún tipo de dolor, y en dos casos estuvo relacionado con Prevotella spp. Se encontró una colonia de F. nucleatum resistente a amoxicilina y con producción de ß-lactamasa, y otra de F. nucleatum resistente a metronidazol. Una colonia de P. propionicum/avidus presentó resistencia intermedia a amoxicilina y con producción de ß-lactamasa. Se encontró la presencia de bacterias anaerobias estrictas/aerotolerantes en los pacientes con infecciones endodónticas primarias. Existen algunos microrganismos relacionados con algún tipo de dolor, como F. nucleatum y P. micra. Los hallazgos muestran presencia de F. nucleatum resistentes a los antimicrobianos evaluados.

The objective of this study is to describe the composition of the strict / aerotolerant anaerobic microbiota in primary endodontic infections, antimicrobial susceptibility, and the association with clinical variables. Samples were taken from seven patients with symptomatic or asymptomatic pulp necrosis. conservation techniques, cultivation, incubation and identification of strict / aerotolerant anaerobes. We used the agar dilution method to determine the antimicrobial susceptibility to amoxicillin and metronidazole. A total of 32 strains, 20 (62.5 %) were isolated were strict / aerotolerant anaerobes, and 8 (25 %) facultative anaerobe organisms. The strict anaerobe / more Fusobacterium nucleatum was frequently aerotolerant, it was isolated in three cases, all related to some type of pain, and in two cases it was related to Prevotella spp. a colony of F. nucleatum resistant to amoxicillin and ß-lactamase production was found, and another F. nucleatum resistant to metronidazole. A colony of P. propionicum / avidus presented intermediate amoxicillin and ß-lactamase producing resistance. Conclusions: the presence of strict anaerobic bacteria / aerotolerant in patients with primary endodontic infections was found. There is some related pain, as F. nucleatum and P. micra microorganisms. The findings show the presence of F. nucleatum resistant to the antimicrobial organisms evaluated.

In vivo and in vitro efficacy of Nigella sativa aqueous extract on blastocystis hominis

Metronidazole [MTZ] was the most widely accepted treatment for Blastocystis hominis [B. hominis] with high treatment failure rate, resistance and potential mutagenic and carcinogenic effects so there is urgent need to find out new, effective and safe treatment against B. hominis. The present research aimed to evaluate the therapeutic effect of the aqueous extract of Nigella sativa [NS] at different doses on B. hominis in vitro and in vivo in comparison to MTZ as a control drug. Isolates of B. hominis were obtained from patients complaining of diarrhea and abdominal pain. Isolates were cultured in egg diphasic medium [LE] for in vitro study and to adjust proper inoculating dose for in vivo study. The aqueous extract of NS at concentrations of 100 and 500?g/ml showed a potent lethal effect on B. hominis isolates in vitro. Caecal tissue of experimentally infected and treated mice with two different doses of NS [250 and 500mg/kg/d] were examined histopathologically and compared with that of mice infected and treated by two doses of MTZ [62 and 125 mg/kg/d] as control drug and Infected untreated mice as negative control group. Histopathological examination of infected untreated group showed all pathological degrees in the caecal tissue while infected treated one showed remission of pathological changes especially with higher dose [500mg/kg]. Present study proved that N. sativa had inhibitory effect on B. hominis in vitro and prevented cytopathic effect in infected mice inoculated orally with B. hominis

Controlling wound odor with metronidazole: a systematic review / Control del olor de heridas con metronidazol: revisión sistemática / Controle do odor de feridas com metronidazol: revisão sistemática

AbstractOBJECTIVEVerifying the evidence of therapeutic efficacy in the topical application of metronidazole for controlling wound odor.METHODSA systematic literature review, according to the Cochrane Collaboration recommendations.RESULTS329 articles were identified in the Cochrane, LILACS, SciELO, CINAHL and PubMed databases, with 14 of them being included in the final sample. Two of the studies were double-blind randomized clinical trial studies.CONCLUSIONThe actual effectiveness of metronidazole in controlling wound odor cannot yet be evidenced due to the absence of strong evidence from studies on the subject, despite clinical practice recommending its benefits.

ResumenOBJETIVOVerificar las evidencias de la aplicación tópica de metronidazol en la efectividad terapéutica para el control del olor de heridas.MÉTODORevisión sistemática de literatura, según las recomendaciones de la Cochrane Collaboration.RESULTADOSSe identificaron 329 artículos en las bases de datos Cochrane, LILACS, ScIELO, Cinahl y PubMed, incluyéndose 14 de ellos en la muestra final. De esos, dos estudios son del tipo ensayo clínico, randomizado y doble ciego.CONCLUSIÓNEn virtud de la ausencia de estudios de fuerte evidencia acerca de la efectividad del metronidazol en el control del olor en heridas, aún no se puede evidenciar su real efectividad para dicho fin, pese a que la práctica clínica recomiende sus beneficios.

ResumoOBJETIVOVerificar as evidências da aplicação tópica de metronidazol na eficácia terapêutica para controle de odor de feridas. Método: Revisão sistemática de literatura, segundo as recomendações da Cochrane Collaboration .RESULTADOSIdentificaram-se 329 artigos nas bases de dados Cochrane, LILACS, ScIELO, Cinahl e PubMed, incluindo-se 14 deles na amostra final. Desses, dois estudos são do tipo ensaio clínico, randomizado e duplo-cego.CONCLUSÃODevido à ausência de estudos de forte evidência sobre a eficácia do metronidazol no controle de odor em feridas, ainda não se pode evidenciar a sua real eficácia para tal objetivo, apesar da prática clínica recomendar seus benefícios.

Long-term evaluation of the antimicrobial susceptibility and microbial profile of subgingival biofilms in individuals with aggressive periodontitis

This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP) patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX), amoxicillin (AMX) and metronidazole (MET). GAP patients allocated to the placebo (C, n = 15) or test group (T, n = 16) received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg)/MET (250 mg) or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3–4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs) of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05) and AMX (p < 0.01) were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05). For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota.

Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey

INTRODUCTION: Antibiotic resistance is the main factor that affects the efficacy of current therapeutic regimens against Helicobacter pylori. This study aimed to determine the rates of resistance to efficacy clarithromycin, amoxicillin, tetracycline, levofloxacin and metronidazole among H. pylori strains isolated from Turkish patients with dyspepsia. METHODS: H. pylori was cultured from corpus and antrum biopsies that were collected from patients with dyspeptic symptoms, and the antimicrobial susceptibility of H. pylori was determined using the E-test (clarithromycin, amoxicillin, tetracycline, metronidazole and levofloxacin) according to the EUCAST breakpoints. Point mutations in the 23S rRNA gene of clarithromycin-resistant strains were investigated using real-time PCR. RESULTS: A total of 98 H. pylori strains were isolated, all of which were susceptible to amoxicillin and tetracycline. Of these strains, 36.7% (36/98) were resistant to clarithromycin, 35.5% (34/98) were resistant to metronidazole, and 29.5% (29/98) were resistant to levofloxacin. Multiple resistance was detected in 19.3% of the isolates. The A2143G and A2144G point mutations in the 23S rRNA-encoding gene were found in all 36 (100%) of the clarithromycin-resistant strains. Additionally, the levofloxacin MIC values increased to 32 mg/L in our H. pylori strains. Finally, among the clarithromycin-resistant strains, 27.2% were resistant to levofloxacin, and 45.4% were resistant to metronidazole. CONCLUSIONS: We conclude that treatment failure after clarithromycin- or levofloxacin-based triple therapy is not surprising and that metronidazole is not a reliable agent for the eradication of H. pylori infection in Turkey. .

Evaluation of Giardia duodenalis viability after metronidazole treatment by flow cytometry

Giardia duodenalis (syn. lamblia; syn. intestinalis) susceptibility testing is not routinely performed because the classical culture methods are very time-consuming and laborious. We developed a novel flow cytometry (FC) assay to evaluate the susceptibility of G. duodenalis trophozoites to metronidazole (MTZ). Different concentrations of MTZ were added to cultures of trophozoites (10 5 /mL) and the cultures were incubated for different periods. The 50% inhibitory concentration was calculated and propidium iodide (PI) was used to quantify the number of dead cells. After treatment, PI-positive trophozoites increased with increasing drug concentration and exposure time. An excellent correlation was found between FC and the classical method. A novel, accurate and reliable method is now available to evaluate G. duodenalis viability. .

Validation of a modified fluorimetric assay for the screening of trichomonacidal drugs

A fluorimetric microassay that uses a redox dye to determine the viability of the flagellate Trichomonas vaginalis has been optimised to provide a more sensitive method to evaluate potential trichomonacidal compounds. Resazurin has been used in recent years to test drugs against different parasites, including trichomonadid protozoa; however, the reproducibility of these resazurin-based methods in our laboratory has been limited because the flagellate culture medium spontaneously reduces the resazurin. The objective of this work was to refine the fluorimetric microassay method previously developed by other research groups to reduce the fluorescence background generated by the media and increase the sensitivity of the screening assay. The experimental conditions, time of incubation, resazurin concentration and media used in the microtitre plates were adjusted. Different drug sensitivity studies against T. vaginalis were developed using the 5-nitroimidazole reference drugs, new 5-nitroindazolinones and 5-nitroindazole synthetic derivatives. Haemocytometer count results were compared with the resazurin assay using a 10% solution of 3 mM resazurin dissolved in phosphate buffered saline with glucose (1 mg/mL). The fluorimetric assay and the haemocytometer counts resulted in similar percentages of trichomonacidal activity in all the experiments, demonstrating that the fluorimetric microtitre assay has the necessary accuracy for high-throughput screening of new drugs against T. vaginalis.

Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

Antibiotics are important adjuncts in the treatment of infectious diseases, including periodontitis. The most severe criticisms to the indiscriminate use of these drugs are their side effects and, especially, the development of bacterial resistance. The knowledge of the biological mechanisms involved with the antibiotic usage would help the medical and dental communities to overcome these two problems. Therefore, the aim of this manuscript was to review the mechanisms of action of the antibiotics most commonly used in the periodontal treatment (i.e. penicillin, tetracycline, macrolide and metronidazole) and the main mechanisms of bacterial resistance to these drugs. Antimicrobial resistance can be classified into three groups: intrinsic, mutational and acquired. Penicillin, tetracycline and erythromycin are broad-spectrum drugs, effective against gram-positive and gram-negative microorganisms. Bacterial resistance to penicillin may occur due to diminished permeability of the bacterial cell to the antibiotic; alteration of the penicillin-binding proteins, or production of β-lactamases. However, a very small proportion of the subgingival microbiota is resistant to penicillins. Bacteria become resistant to tetracyclines or macrolides by limiting their access to the cell, by altering the ribosome in order to prevent effective binding of the drug, or by producing tetracycline/macrolide-inactivating enzymes. Periodontal pathogens may become resistant to these drugs. Finally, metronidazole can be considered a prodrug in the sense that it requires metabolic activation by strict anaerobe microorganisms. Acquired resistance to this drug has rarely been reported. Due to these low rates of resistance and to its high activity against the gram-negative anaerobic bacterial species, metronidazole is a promising drug for treating periodontal infections.

The activity of a metronidazole analogue and its β-cyclodextrin complex against Trypanosoma cruzi

In this study we prepared an inclusion complex between an iodide analogue of metronidazole (MTZ-I) and cyclodextrin (CD) to develop a safer and more effective method of treating Trypanosoma cruzi infections. According to our results, MTZ-I and MTZ-I:β-CD were 10 times more active than MTZ, demonstrating that the presence of an iodine atom on the side chain increased the trypanocidal activity while maintaining its cytotoxicity. The selective index shows that MTZ-I was 10 times more active against T. cruzi than it was against mammalian cells. The modification of MTZ side chains provides a promising avenue for the development of new drugs.

The presence of dsRNA virus in Trichomonas vaginalis isolates from symptomatic and asymptomatic Indian women and its correlation with in vitro metronidazole sensitivity.

Purpose: Trichomonas vaginalis, a protozoan parasite, is the causative agent of human trichomoniasis, the most common non-viral sexually transmitted disease. The infection encompasses from a complete asymptomatic presentation to severe sequelae; yet, the virulence markers have been poorly understood. It is suggested that the presence of Trichomonas vaginalis virus (TVV) in T. vaginalis may have an impact on its virulence, and its relatedness to in vitro metronidazole resistance has been reported. The aim of the study was to assess the presence of TVV in fresh and Long -Term Cultivated ( LTC) maintained T. vaginalis isolates from symptomatic (S) and asymptomatic (AS) Indian women and its relatedness, if any, with symptomatology and in vitro drug sensitivity. Materials and Methods: One thousand women (537 S and 463 AS) were screened for the presence of T. vaginalis by wet smear and culture examination of vaginal swab and urine sample. Fresh and LTC (6 months-2 years) maintained 15 isolates each from 15 S and 15 AS women were subjected to agarose gel electrophoresis following total cellular RNA extraction to evaluate the presence of double stranded (ds) RNA viral infection. The susceptibility of isolates to metronidazole was determined in vitro. Results: On agarose gel electrophoresis, three bands (5.5, 2.5 and 1.5 kb) were observed in all the 30 fresh isolates from 15 S and 15 AS women and only in 7 LTC isolates from 3 S and 4 AS women. All the fresh isolates harbouring TVV were found to be sensitive to metronidazole in vitro irrespective of the symptomatology of subjects, and out of seven LTC isolates harbouring TVV, six were sensitive to metronidazole and one showed borderline resistance. Conclusions: The results suggest that the presence of TVV alone may not be a virulence marker and loss of TVV on LTC appears to be related to drug resistance. The T. vaginalis Indian isolates are sensitive to metronidazole.