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1.
Int. j. odontostomatol. (Print) ; 14(3): 448-456, 2020. tab, graf
Article in English | LILACS | ID: biblio-1114920

ABSTRACT

Enterococci are important nosocomial pathogens due to their intrinsic multiresistance and the acquisition of new antibiotic resistance genes (ARG). Enterococcus faecalis has been shown to be one of the main pathogens in persistent endodontic infections, therefore, the main objective of this study was to evaluate the phenotype and resistance genotype of strains of E. faecalis isolated from teeth with persistent endodontic lesions, to the most commonly prescribed antibiotics in dentistry. Thirteen strains of E. faecalis of different pulsotype were analyzed to evaluate the susceptibility to antibiotics, amoxicillin, amoxicillin/clavulanic acid, tetracycline, erythromycin and metronidazole, using the Epsilometer test (E- test) and the presence of beta-lactamases with nitrocefin test. Finally, the detection of ARG was performed with a molecular polymerase chain reaction (PCR) technique and confirmed by the sequencing of the amplification products. Fisher's exact test was used, using 95 % confidence. Regarding the phenotype of resistance, the evaluated strains, independent of the pulsotype, were totally resistant to the action of metronidazole. Antibiotics with higher minimum inhibitory concentration (MIC) after metronidazole include tetracycline and erythromycin. In contrast, lower MIC are applied to the combination of amoxicillin with clavulanic acid. The nitrocefin test was positive only in one strain. Genotypically, two genetically distant strains isolated from a single patient, presented a genotype of resistance to erythromycin, determined by the presence of the ermB gene. No statistically significant relationship was found between phenotypic resistance and the presence of ARG in relation to erythromycin (p> 0.05). It was concluded that isolates of E. faecalis from persistent endodontic infections showed phenotypes of resistance to several antimicrobial agents, all of which were susceptible to amoxicillin/clavulanic acid. Periodic evaluation of susceptibility to antibiotics is suggested as an important practice for the surveillance of antibiotic resistance in oral strains.


Los enterococos son importantes patógenos nosocomiales debido a su multi resistencia intrínseca y la adquisición de nuevos genes de resistencia a los antibióticos (ARG). Enterococcus faecalis es uno de los principales patógenos en infecciones endodónticas persistentes, por lo tanto, el objetivo principal de este estudio fue evaluar el fenotipo y el genotipo de resistencia de cepas de E. faecalis aisladas de dientes con lesiones endodóncicas persistentes, a los antibióticos comúnmente recetados en odontología. Se analizaron 13 cepas de E. faecalis de diferentes pulsotipos para evaluar la susceptibilidad a los antibióticos, amoxicilina, amoxicilina / ácido clavulánico, tetraciclina, eritromicina y metronidazol, utilizando la prueba de Epsilometría (E-test) y la presencia de beta-lactamasas con prueba de nitrocefina. Finalmente, la detección de ARG se realizó con una técnica molecular de reacción en cadena de la polimerasa (PCR) y se confirmó mediante la secuenciación de los productos de amplificación. Se utilizó la prueba exacta de Fisher, con un 95 % de confianza. En cuanto al fenotipo de resistencia, las cepas evaluadas, independientes del pulsotipo, fueron totalmente resistentes a la acción del metronidazol. Los antibióticos con los valores más altos de concentración mínima inibitoria (CMI) después del metronidazol incluyen tetraciclina y eritromicina. En contraste, las CMI mas bajas se aplican a la combinación de amoxicilina con ácido clavulánico. La prueba de nitrocefina fue positiva solo en una cepa. Genotípicamente, dos cepas distantes genéticamente, aisladas de un mismo paciente fueron positivas para el gen ermB. No se encontró una relación estadísticamente significativa entre la resistencia fenotípica y la presencia de ARG en relación con la eritromicina (p> 0,05). Se concluyó que los aislamientos de E. faecalis de infecciones endodónticas persistentes mostraron fenotipos de resistencia a varios agentes antimicrobianos, todos los cuales fueron susceptibles a amoxicilina / ácido clavulánico. Se sugiere una evaluación periódica de la susceptibilidad a los antibióticos como una práctica importante para la vigilancia de la resistencia a los antibióticos en las cepas orales.


Subject(s)
Humans , Enterococcus faecalis/drug effects , Enterococcus faecalis/genetics , Dental Pulp Cavity/microbiology , Anti-Bacterial Agents/pharmacology , Tetracycline , Microbial Sensitivity Tests , Erythromycin , Polymerase Chain Reaction , Clavulanic Acid/pharmacology , Drug Resistance, Bacterial/genetics , Amoxicillin/pharmacology , Metronidazole
2.
Braz. j. infect. dis ; 23(3): 203-206, May-June 2019. graf
Article in English | LILACS | ID: biblio-1039226

ABSTRACT

ABSTRACT Global dissemination of mcr-like genes represents a serious threat to public health since it jeopardizes the effectiveness of colistin, an antibiotic used as a last-resort treatment against highly antibiotic-resistant bacteria. In 2017, a mcr-1-positive isolate of Escherichia coli was found in Chile for the first time. Herein we report the genetic features of this strain (UCO-457) by whole-genome sequencing (WGS) and conjugation experiments. The UCO-457 strain belonged to ST4204 and carried a 285 kb IncI2-type plasmid containing the mcr-1 gene. Moreover, this plasmid was transferred by conjugation to an E. coli J53 strain at high frequency. The isolate harbored the cma, iroN, and iss virulence genes and did carry resistance genes to trimethoprim/sulfamethoxazole and fluoroquinolones. Other antibiotic resistance determinants such as β-lactamases-encoding genes were not detected, making the isolate highly susceptible to these antibiotics. Our results revealed that such susceptible isolates could be acting as platforms to disseminate plasmid-mediated colistin resistance. Based on this evidence, we consider that mcr-like prevalence deserves urgent attention and should be examined not only in highly resistant bacteria but also in susceptible isolates.


Subject(s)
Humans , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Outpatients , Chile , Escherichia coli/drug effects , Disk Diffusion Antimicrobial Tests , Anti-Bacterial Agents/pharmacology
3.
Int. j. odontostomatol. (Print) ; 12(1): 113-119, Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-893310

ABSTRACT

ABSTRACT: Molecular techniques that provide valuable information about the epidemiology of oral strains. The purpose of this study was to determine the genetic relatedness of 83 Enterococcus faecalis strains isolated from treated root canals. These strains were obtained from patients who were treated for persistent endodontic infections. E. faecalis isolates were molecular typed by Pulsed Field Gel Electrophoresis using Smal. Ten clonal groups and 13 pulse types with 38.7 % similarity for the less related strains were identified. Genetic heterogeneity among strains from different patients and a high level of genetic homogeneity among intrapatient strains were observed. Therefore, restriction endonuclease fingerprinting of genomic DNA from E. faecalis strains confirmed the polyclonality of the isolates obtained from the root canals of patients diagnosed with persistent endodontic infections, compared with other reports. These results provide additional data for a better understanding of the epidemiological aspects of root canal infections by E. faecalis.


RESUMEN: Las técnicas moleculares proporcionan información valiosa sobre la epidemiología de aislados orales. El propósito de este estudio fue determinar la relación genética de 83 cepas de Enterococcus faecalis aisladas de conductos radiculares tratados. Estas cepas se obtuvieron de pacientes que fueron tratados por infecciones endodónticas persistentes. Los aislados de E. faecalis se tipificaron molecularmente por electroforesis en gel de campo pulsado usando Smal. Se identificaron diez grupos clonales y 13 pulsotipos con un 38,7 % de similitud para las cepas menos relacionadas. Se observó heterogeneidad genética entre las cepas de diferentes pacientes y un alto nivel de homogeneidad genética entre las cepas intrapacientes. Por lo tanto, la toma de huellas dactilares a traves de restricción de ADN genómico de cepas de E. faecalis confirmó la policlonalidad de los aislados obtenidos de los conductos radiculares de pacientes diagnosticados con infecciones endodónticas persistentes, en comparación con otros informes. Estos resultados proporcionan datos adicionales para una mejor comprensión de los aspectos epidemiológicos de las infecciones del conducto radicular por E. faecalis.


Subject(s)
Humans , Periapical Periodontitis/microbiology , Enterococcus faecalis/isolation & purification , Tooth Apex/microbiology , DNA, Bacterial/analysis , Bacterial Typing Techniques , Gram-Positive Bacterial Infections/microbiology , Electrophoresis, Gel, Pulsed-Field , Dental Pulp Cavity/microbiology
4.
Rev. chil. infectol ; 35(1): 7-14, 2018. tab, graf
Article in Spanish | LILACS | ID: biblio-899771

ABSTRACT

Resumen Desde el inicio de la era antimicrobiana se han ido seleccionando gradualmente cepas de Staphylococcus aureus resistentes a antimicrobianos de amplio uso clínico. Es así como en 1960 se describen en Inglaterra las primeras cepas resistentes a meticilina, y algunos años después son informadas en hospitales de Chile. Actualmente, S. aureus resistente a penicilinas antiestafilocóccicas es endémico en los hospitales de nuestro país y del mundo, siendo responsable de una alta morbimortalidad. La resistencia es mediada habitualmente por la síntesis de una nueva transpeptidasa, denominada PBP2a o PBP2' que posee menos afinidad por el β-lactámico, y es la que mantiene la síntesis de peptidoglicano en presencia del antimicrobiano. Esta nueva enzima se encuentra codificada en el gen mecA, a su vez inserto en un cassette cromosomal con estructura de isla genómica, de los cuales existen varios tipos y subtipos. La resistencia a meticilina se encuentra regulada, principalmente, por un mecanismo de inducción de la expresión del gen en presencia del β-lactámico, a través de un receptor de membrana y un represor de la expresión. Si bien se han descrito mecanismos generadores de resistencia a meticilina mec independientes, son categóricamente menos frecuentes.


Staphylococcus aureus isolates resistant to several antimicrobials have been gradually emerged since the beginning of the antibiotic era. Consequently, the first isolation of methicillin-resistant S. aureus occurred in 1960, which was described a few years later in Chile. Currently, S. aureus resistant to antistaphylococcal penicillins is endemic in Chilean hospitals and worldwide, being responsible for a high burden of morbidity and mortality. This resistance is mediated by the expression of a new transpeptidase, named PBP2a or PBP2', which possesses lower affinity for the β-lactam antibiotics, allowing the synthesis of peptidoglycan even in presence of these antimicrobial agents. This new enzyme is encoded by the mecA gene, itself embedded in a chromosomal cassette displaying a genomic island structure, of which there are several types and subtypes. Methicillin resistance is mainly regulated by an induction mechanism activated in the presence of β-lactams, through a membrane receptor and a repressor of the gene expression. Although mec-independent methicillin resistance mechanisms have been described, they are clearly infrequent.


Subject(s)
Bacterial Proteins/genetics , Genetic Structures/genetics , Penicillin-Binding Proteins/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Bacterial Proteins/drug effects , Molecular Structure , Chromosomes, Bacterial/drug effects , Penicillin-Binding Proteins/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Genes, Bacterial/drug effects , Methicillin/pharmacology , Methicillin/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry
5.
Rev. chil. infectol ; 34(5): 476-484, oct. 2017. tab, graf
Article in Spanish | LILACS | ID: biblio-899745

ABSTRACT

Resumen En la actualidad, la diseminación de enterobacterias productoras de carbapenemasas se considera un grave problema en clínica debido al fracaso en el tratamiento de las infecciones que ellas producen. Entre las carbapenemasas, la enzima KPC se ha diseminado mundialmente y ha sido identificada en las principales especies de enterobacterias relacionadas con infecciones asociadas a la atención en salud, con claro predominio de Klebsiella pneumoniae a nivel mundial. El gen blaKPC es transportado, principalmente, por el transposón Tn4401, detectado en diversas especies de enterobacterias con distintos secuencio-tipo (ST) y diferente origen geográfico. Adicionalmente, se han descrito nuevas plataformas genéticas que se distinguen del Tn4401 original debido a inserciones y deleciones de otros genes. Los plásmidos que albergan el gen blaKPC pueden ser del tipo conjugativo y no conjugativo movilizable, y además contener otros determinantes genéticos de resistencia. Las cepas productoras de KPC pueden presentar diversos niveles de resistencia a los carbapenémicos, debido a la participación de mecanismos adicionales como diferente grado de expresión de porinas y bombas de expulsión asociados con la producción de β-lactamasas de espectro extendido y/o AmpC. Sin embargo, las carbapenemasas, con KPC como la enzima más frecuente, otorgan grados de resistencia más elevados.


The dissemination of carbapenemase-producing Enterobacteriaceae is currently considered a serious clinical problem due to the failure in the treatment of infections produced by them. Among the carbapenemases, the enzyme KPC has spread worldwide and has been identified in the main enterobacterial species related with healthcareassociated infections, although Klebsiella pneumoniae is the predominant specie. The blaKPC gene is transported, mainly by the transposon Tn4401, detected in various enterobacterial species of different sequence types (ST) and geographical origin. In addition, new genetic platforms that are distinguished, from Tn4401 because of insertions or deletions of other genes have been described. Plasmids containing the blaKPC gene can be conjugative and mobilizable non-conjugative plasmids, and can carry other genetic determinants of resistance. The KPC-producing strains may have different levels of resistance to carbapenems, due to the involvement of additional mechanisms such as different expression levels of porins and efflux pumps associated with the production of extended spectrum β-lactamases and/or AmpC. However, the carbapenemases, with KPC as the most common enzyme, provide higher levels of resistance.


Subject(s)
Bacterial Proteins/biosynthesis , beta-Lactamases/biosynthesis , Klebsiella pneumoniae/enzymology , Bacterial Proteins/genetics , beta-Lactamases/genetics , Microbial Sensitivity Tests , Drug Resistance, Bacterial/genetics , Carbapenem-Resistant Enterobacteriaceae , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Anti-Bacterial Agents/pharmacology
6.
Rev. chil. infectol ; 34(4): 413-414, ago. 2017.
Article in Spanish | LILACS | ID: biblio-1042639

ABSTRACT

Currently, there is a controversy in how to determine the minimal inhibitory concentration (MIC) of colistin against Acinetobacter baumannii. We compared three methods, concluding that the addition of Tween-80 (0.002%) to Müller-Hinton broth in the microdilution method could improve MIC determination and it could reduce false resistance.


Subject(s)
Humans , Microbial Sensitivity Tests/methods , Colistin/pharmacology , Acinetobacter baumannii/drug effects , Anti-Bacterial Agents/pharmacology
7.
Int. j. odontostomatol. (Print) ; 10(3): 547-554, dic. 2016.
Article in English | LILACS | ID: biblio-841007

ABSTRACT

Copper was registered as the first solid antimicrobial material. Its availability makes it an important option as an antibacterial agent. At nanoparticle size it does not exceed 100 nm, allowing close interaction with microbial membranes, enhancing its effect even more. Copper generates toxic hydroxyl radicals that damage cell membranes of Gram-negative and Gram-positive bacteria, among the latter, Enterococcus faecalis, which are present in infected radicular canals. Synthesis of metal nanoparticles with antimicrobial properties has become a viable alternative and has promising applications in the fight against pathogenic microorganisms. Furthermore, the use of some polymers to stabilize nanoparticles increases their release time and may as well decrease the risk of bacterial recolonization and biofilm formation within the ducts, enhancing the antimicrobial properties of these compounds.The aim of this article is to conduct a systematic review of the literature on antimicrobial copper nanoparticles, their current applications and their potential use in the area of oral health, specifically in the field of endodontics.


El cobre fue registrado como el primer material antimicrobiano sólido y su disponibilidad permite que constituya una importante opción como agente antibacteriano. Al tamaño de nanopartícula no supera los 100 nm, lo que permite una interacción estrecha con las membranas microbianas, potenciando aún más su efecto. Genera radicales hidroxilos tóxicos que provocan daño en la membrana celular de bacterias Gram negativas y Gram positivas, entre estas últimas, Enterococcus faecalis, presente en conductos radiculares infectados. Por lo que la síntesis de nanopartículas metálicas con propiedades antimicrobianas se ha vuelto una alternativa viable con aplicaciones prometedoras en la lucha contra microorganismos patógenos. Además, utilizando algunos polímeros para estabilizar las nanopartículas se aumenta el tiempo de liberación de éstas y se disminuye el riesgo de recolonización bacteriana y la formación de biopelículas al interior de los conductos, mejorando las propiedades antimicrobianas de estos compuestos. El propósito de este artículo es realizar una revisión sistemática de la literatura acerca de nanopartículas de cobre como antimicrobiano, sus aplicaciones actuales y su potencial uso en el área de la salud oral, específicamente en el campo de la Endodoncia.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Copper/pharmacology , Dental Pulp Cavity/drug effects , Metal Nanoparticles/chemistry , Enterococcus faecalis/drug effects
8.
Rev. chil. infectol ; 33(5): 519-523, oct. 2016. graf, tab
Article in Spanish | LILACS | ID: biblio-844402

ABSTRACT

Background: Nosocomial infections caused by multiresistant Gram-positive cocci are a serious problem for public health systems worldwide. The use of copper surfaces in hospital environments has proven to be an effective alternative for the control of various microorganisms, including multiresistant nosocomial pathogens. Aim: To determine the association between antibiotic multiresistance and higher levels of copper tolerance in Gram-positive cocci isolated from Chilean hospitals, which might confer a selective advantage in environments with copper. Methods: The ionic copper tolerance levels were evaluated using the Mueller Hinton agar dilution method, in S. aureus and Enterococcus spp. strains with different levels of susceptibility to clinically relevant antibiotics. Results: A statistically significant association between higher levels of tolerance to copper ion and multi-resistance to antibiotics in Enterococcus spp. was observed.


Introducción: Las infecciones nosocomiales, producidas por bacterias cocáceas grampositivas multi-resistentes constituyen un serio problema para los sistemas de salud pública mundial. El uso de superficies de cobre en ambientes hospitalarios ha demostrado ser una alternativa efectiva para el control de diversos microorganismos, incluyendo patógenos nosocomiales multi-resistentes. Objetivo: Determinar la asociación entre la multi-resis-tencia a antimicrobianos y mayores niveles de tolerancia a cobre en bacterias cocáceas grampositivas aisladas de hospitales chilenos, que podrían conferir una ventaja selectiva en ambientes cobrizados. Material y Métodos: Se evaluó los niveles de tolerancia a cobre iónico en grupos de cepas de Staphylococcus aureus y Enterococcus spp. con distintos grados de susceptibilidad a antimicrobianos de relevancia clínica, mediante el método de dilución en agar Mueller Hinton. Resultados: Se observó una asociación estadísticamente significativa entre mayores niveles de tolerancia a cobre iónico y la multi-resistencia a antimicrobianos en Enterococcus spp.


Subject(s)
Humans , Staphylococcus aureus/drug effects , Enterococcus/drug effects , Copper/pharmacology , Anti-Bacterial Agents/pharmacology , Microbial Sensitivity Tests , Chile , Drug Resistance, Multiple, Bacterial/drug effects
9.
Int. j. odontostomatol. (Print) ; 9(3): 505-510, dic. 2015. ilus
Article in English | LILACS | ID: lil-775479

ABSTRACT

The incomplete disinfection of root canal system has been reported as the main cause of post-treatment disease, due to the persistence of bacteria. For over thirty years Enterococcus faecalis has been considered the most common bacterial species isolated from persistent root canal infections, resisting antibacterial agents, such as chlorhexidine and calcium hydroxide. Several studies have indicated that copper has optimal disinfecting capacities in a hospital environment. Aimed to know the ex vivo effect of copper sulfate (CuSO4) on E. faecalis. Thirty-six extracted human tooth root canals were inoculated with E. faecalis ATCC 29212. These root canals had undergone endondontic procedures with a rotatory system. The effect of CuSO4 was determined by plate count method of E. faecalis obtained from one sample of each tooth under three incubation times (4th, 7th and 10th day). The canals medicated with CuSO4, the bacterial count decreased 6 log after 4 days and remained as such without statistically significant change until the tenth day. It is an indisputable fact of its antibacterial action. The bacterial persistence may be due to the ability of E. faecalis to remain viable in root canals up to 12 months without additional nutrients. These preliminary results couldbe used for further scientific work assessing the potential for the use of cooper in dentistry.


La desinfección incompleta del sistema de canales radiculares ha sido reportada como la principal causa de infección post tratamiento, debido a la persistencia bacteriana. Por más de 30 años, Enterococcus faecalis se ha considerado una de las especies bacterianas más comunes aisladas de infecciones persistentes del canal radicular, resistiendo a agentes antibacterianos, como clorhexidina e hidróxido de calcio. Varios estudios han indicado que el cobre tiene una capacidad de desinfección óptima en un entorno hospitalario. Con el objetivo de conocer el efecto ex vivo de sulfato de cobre (CuSO4) sobre E. faecalis. Treinta y seis canales radiculares de dientes humanos extraídos fueron inoculados con E. faecalis ATCC 29212. Estos canales radiculares fueron previamente sometidos a instrumentación con un sistema de rotación. El efecto de CuSO4 se determinó por el método de recuento en placa de E. faecalis a partir de una muestra de cada diente en tres tiempos de incubación (4, 7 y 10 días). En los canales medicados con CuSO4, el recuento de bacterias se redujo 6 log después de 4 días y se mantuvo como tal sin cambio estadísticamente significativo hasta el día 10. Esto demuestra su poder antibacteriano. La persistencia bacteriana pudo ser deberse a la capacidad de E. faecalis para seguir siendo viable en canales hasta 12 meses sin nutrientes adicionales. Estos resultados preliminares podrían ser utilizados para otros trabajos científicos que evaluen el potencial uso de cobre en odontología.


Subject(s)
Humans , Enterococcus faecalis/drug effects , Copper Sulfate/pharmacology , Dental Pulp Cavity/microbiology , Anti-Bacterial Agents/pharmacology , Retrospective Studies , Longitudinal Studies , Dental Pulp Cavity/drug effects , Bacterial Load
10.
Braz. j. oral sci ; 14(3): 240-245, July-Sept. 2015. tab, graf
Article in English | LILACS, BBO | ID: lil-770540

ABSTRACT

Abstract Aim: To isolate and identify in a Chilean population,Enterococcus spp. from root canals with persistent chronic apical periodontitis (CAP) and to investigate the potential correlation between the bacteria and the observed clinical features. Methods: Twenty patients with indication for endodontic retreatment due to persistent CAP were selected. Data from patient general health and dental clinical history were recorded. During retreatment, a microbial sample was obtained from the root canal and inoculated in a selectiveEnterococcus medium. Using bacterial cultivation methods, bacterial isolates belonging to the genusEnterococcus were identified. The relationship between the number of colony-forming units of Enterococcus spp. and patient clinical data was assessed statistically by the Pearson Chi square and Fisher exact tests. Finally, a Polymerase Chain Reaction (PCR) assay to determine the most prevalent species of Enterococcus spp. was conducted in the clinical samples, and the results were analyzed by a proportion comparison test. Results: Enterococcus spp. strains were isolated in 70% of the patients. Most of them (98.8%) accounted for Enterococcus faecalis and only 1.2% for Enterococcus faecium. A high frequency of E. faecalis was found in teeth with inadequate endodontic treatment or dental crown restorations. Conclusions: This study concluded that E. faecalis is prevalent in root canals with persistent CAP in a Chilean population. E. faecium as found in a single case with the poorest root canal filling. Further studies are still required to investigate the presence of other species, which may be linked to persistent chronic apical periodontitis.


Subject(s)
Humans , Male , Female , Young Adult , Periapical Granuloma , Enterococcus , Enterococcus faecalis
11.
Rev. chil. infectol ; 32(2): 135-141, abr. 2015. ilus, tab
Article in Spanish | LILACS | ID: lil-747515

ABSTRACT

Introduction: Metronidazole is the antibiotic of choice for the management of infections caused by anaerobes. Its administration requires multiple daily doses causing increased medication errors. Due to its high post-antibiotic effect and rapid concentration-dependent bactericidal activity, administration of this antibiotic in an extended dosing interval would achieve PK/PD parameters effectively. Objective: To assess the probability of achieving effective PK/PD relationship with the administration of 1,000 mg every 24 hours of metronidazole for Bacteroides fragilis infections. Methods: A clinical trial was conducted in a group of volunteers who received a single oral dose of 500 or 1,000 mg of metronidazole. Determinations of values of Cmax, t max, and AUCC0-24 h. determined using the trapezoidal method, were obtained for a Markov simulation that would allow for determining the likelihood of achieving a AUC0-24 h/MIC ratio above 70 for infections caused by susceptible B. fragilis. Results: Cmax (24,03 ± 6,89 mg/L) and t max (1,20 ± 0.80 hrs) and the value of AUC0-24 h (241.91 ± 48.14 mg * h/L) were determined. The probability of obtaining a AUC0-24 h/MIC ratio greater than 70 was greater than 99%. Conclusion: From a pharmacokinetic perspective, with the administration of a daily dose of 1,000 mg of metronidazole, it is possible to achieve a therapeutic goal of AUC0-24 h/MIC ratio above 70 for the treatment of anaerobic infections.


Introducción: Metronidazol es el antimicrobiano de elección para el manejo de infecciones anaeróbicas. Su administración requiere de dosis múltiples provocando aumento en errores medicamentosos. Debido al efecto post-antibiótico y a la actividad bactericida concentración-dependiente, la administración de metronidazol en intervalos ampliados de administración permitiría alcanzar parámetros PK/PD efectivos. Objetivo: Evaluar la probabilidad de alcanzar una relación PK/PD efectiva con la administración de 1.000 mg cada 24 h de metronidazol para infecciones por Bacteroides fragilis. Método: Se realizó un ensayo clínico sobre un grupo de voluntarios a quienes se les administró una monodosis oral de 500 y 1.000 mg de metronidazol, respectivamente. Se establecieron parámetros farmacocinéticos empleando el método trapezoidal. Se realizó una simulación de Markov que permitiera establecer la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 en infecciones por B. fragilis. Resultados: Se determinaron los valores de Cmax (24,03 ± 6,89 mg/L), t max (1,20± 0,8h) y AUC0-24 h (241,91 ± 48,14 mg*h/L), con lo cual la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 con 1.000 mg de metronidazol fue superior a 99%. Conclusión: Con la administración de 1.000 mg cada 24 h sería posible alcanzar una relación PK/PD efectiva para el tratamiento de infecciones anaeróbicas.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Anti-Bacterial Agents/pharmacokinetics , Bacteroides Infections/drug therapy , Bacteroides Infections/metabolism , Bacteroides fragilis , Metronidazole/pharmacokinetics , Administration, Oral , Anti-Bacterial Agents/administration & dosage , Drug Administration Schedule , Markov Chains , Metronidazole/administration & dosage
12.
Rev. méd. Chile ; 130(1): 45-49, ene. 2002. ilus, tab
Article in Spanish | LILACS | ID: lil-310251

ABSTRACT

Background: Enterococcus is a bacterial genus with low virulence. However, in the last years, the importance of some enterococcus species as nosocomial pathogens has increased, specially due to their resistance to some antimicrobial. Aim: To identify enterococcus strains using classical biochemical techniques and genomic amplification with Polymerase Chain Reaction (PCR). Material and methods: Three hundred and five enterococcus strains, isolated between 1996 and 1999, from different clinical specimens in hospitals and other centers of the VIIIth Region of Chile, were studied. The isolates were identified, to the species level, according to the scheme proposed by Carvalho et al. Identification of some strains was confirmed by PCR. Results: Eighty nine percent of isolates were identified as E fócalis, 10.2 percent as E fócium and 3.3 percent as other species. Conclusions: PCR is a fast and promising technique, useful in the identification of Enterococcus species


Subject(s)
Humans , Enterococcus , Polymerase Chain Reaction , Electrophoresis, Agar Gel , Enterococcus , Genotype
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