[In vitro antibacterial activity of Chilean propolis against Helicobacter pylori]. / Actividad antibacteriana in vitro de propóleos chilenos sobre Helicobacter pylori.

INTRODUCTION: Propolis is a natural product derived from beekeeping. It has anesthetic, anti-inflammatory, immune-stimulant and antibacterial properties on grampositive and gramnegative bacteria. However, little is known regarding its activity on Helicobacter pylori. This bacteria colonizes about half of the world's population and is associated with chronic gastritis, peptic ulcer and gastric cancer. OBJECTIVE: The aim of this study was to evaluate the inhibitory activity of 22 propolis extracts from nine of the 11 beekeeping Chilean regions on 10 strains of H. pylori isolated from gastric mucosa. METHODS: The antibacterial activity of the extracts was determined using the well diffusion method and diffusion disks. RESULTS: 100% of the extracts were active on the tested strains, showing inhibition halos equal to or greater than 15 mm by both methods. CONCLUSIONS: Our results show an effective anti H. pylori activity of propolis. However, additional microbiological studies are needed before a potential clinical utility of these natural products is warranted.

Actividad antibacteriana in vitro de propóleos chilenos sobre Helicobacter pylori / In vitro antibacterial activity of Chilean propolis against Helicobacter pylori

Introduction: Propolis is a natural product derived from beekeeping. It has anesthetic, anti-inflammatory, immune-stimulant and antibacterial properties on grampositive and gramnegative bacteria. However, little is known regarding its activity on Helicobacter pylori. This bacteria colonizes about half of the world’s population and is associated with chronic gastritis, peptic ulcer and gastric cancer. Objective: The aim of this study was to evaluate the inhibitory activity of 22 propolis extracts from nine of the 11 beekeeping Chilean regions on 10 strains of H. pylori isolated from gastric mucosa. Methods: The antibacterial activity of the extracts was determined using the well diffusion method and diffusion disks. Results: 100% of the extracts were active on the tested strains, showing inhibition halos equal to or greater than 15 mm by both methods. Conclusions: our results show an effective anti H. pylori activity of propolis. However, additional microbiological studies are needed before a potential clinical utility of these natural products is warranted.

Introducción: El propóleos es un producto natural derivado de la apicultura que tiene propiedades anestésicas, anti-inflamatorias, inmuno-estimulantes y antibacterianas. Ejerce su acción sobre distintas bacterias grampositivas y gramnegativas. Sin embargo, es muy poco lo que se sabe en relación a su actividad sobre H. pylori, bacteria asociada con gastritis crónica, úlcera gastro-duodenal y cáncer gástrico y que coloniza a alrededor de la mitad de la población mundial. Objetivo: Evaluar la actividad inhibitoria de 22 extractos de propóleos de orígenes botánicos diferentes, provenientes de nueve de las once zonas mielíferas de Chile, en la época de otoño, sobre 10 cepas de H. pylori aisladas de mucosa gástrica. Metodología: La actividad antibacteriana de los extractos se determinó a través del método de difusión en pocillos y de difusión en discos. Resultados: 100% de los extractos fueron activos sobre las cepas ensayadas, observándose halos de inhibición iguales o mayores a 15 mm en ambos métodos. Conclusiones: Los datos obtenidos in vitro en el presente estudio muestran una efectiva actividad anti H. pylori de los propóleos chilenos, siendo necesario estudios microbiológicos y farmacológicos adicionales para avanzar en una posible utilidad clínica de estos productos naturales.

Antibiotic resistance in environmental Escherichia coli - a simple screening method for simultaneous typing and resistance determination.

We describe a simple and standardised screening system (AREB) for surveillance of antibiotic resistant bacteria in the environment. The system consists of 96 well microplates containing eight sets of breakpoint amounts of 10 different antibiotics. The incubated microplates are read by a desktop scanner and the plate images are analysed by special software that automatically presents the resistance data. The AREB method is combined with a rapid typing method, the PhenePlate system, which yields information on the diversity of the bacteria in the studied samples, and on the possible prevalence of resistant clones. In order to demonstrate the usage of AREB, a comparative study on the resistance situation among 970 Escherichia coli isolates from sewage and recipient water in Sweden, Norway and Chile, was performed. Resistance rates to all antibiotics were markedly higher in hospital sewage than in other samples. Our data indicate that the AREB system is useful for comparing resistance rates among E. coli and other environmental indicator bacteria in different countries/regions. Simple handling and automatic data evaluation, combined with low cost, facilitate large studies involving several thousands of isolates.

Subtyping of Chilean Methicillin-Resistant Staphylococcus aureus strains carrying the staphylococcal cassette chromosome mec type I

The cassette chromosome mec (SCCmec) present in methicillin-resistant Staphylococcus aureus (MRSA) has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile) between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile) were originated from two local clones which correspond to Genotype 18 and Genotype 19.

Subtyping of Chilean Methicillin-Resistant Staphylococcus aureus strains carrying the staphylococcal cassette chromosome mec type I.

The cassette chromosome mec (SCCmec) present in methicillin-resistant Staphylococcus aureus (MRSA) has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile) between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile) were originated from two local clones which correspond to Genotype 18 and Genotype 19.

Isolation of Helicobacter pylori in gastric mucosa and susceptibility to five antimicrobial drugs in Southern Chile

Helicobacter pylori colonizes more than 50 percent of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement). Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3 percent) with slightly higher frequency in female (42 percent positive cultures) than male (40.2 percent positive cultures). With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21-30 (55 percent) and 41-50 (52.6 percent) years old, and patients with secondary (43.9 percent) and university (46.2 percent) educational levels. Nineteen (21.6 percent) strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3 percent) showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously.

Isolation of Helicobacter pylori in gastric mucosa and susceptibility to five antimicrobial drugs in Southern chile.

Helicobacter pylori colonizes more than 50% of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement). Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3%) with slightly higher frequency in female (42% positive cultures) than male (40.2% positive cultures). With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21-30 (55%) and 41-50 (52.6%) years old, and patients with secondary (43.9%) and university (46.2%) educational levels. Nineteen (21.6%) strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3%) showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously.

[Association between genotype screening results obtained by PFGE and PCR for hypervariable regions of the mecA gene in methicillin-resistant Staphylococcus aureus]. / Asociación entre los criterios de clasificación genotípica de Staphylococcus aureus resistente a meticilina que se obtuvo mediante electroforesis en geles de campos pulsantes y mediante reacción en cadena de la polimerasa de regiones hipervariables del gen mecA.

INTRODUCTION: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a major epidemiological problem worldwide. METHODS: We determined the degree of association between the genotype screening results obtained by pulse-field gel electrophoresis (PFGE) and polymerase chain reaction (PCR) for 7 hypervariable DNA regions associated with the mecA gene (HVR-mecA PCR), in the epidemiological analysis of 36 MRSA strains unrelated to nosocomial outbreaks, isolated from hospitalized patients at the County Hospital of Valdivia (Chile). RESULTS: The strains were classified into 15 pulse types (A-O) and 5 genotypes (6, 14, 15, 16, and 17) by PFGE and HVR-mecA PCR, respectively. Most of the strains were grouped in pulse types D, E and I, which presented 85.7% similarity. The most common genotypes were 14 (36.1%) and 15 (33.3%). Each genotype detected by HVR-mecA PCR was distributed in more than one pulse type. The degree of association between genotypic screening by PFGE or HVR-mecA PCR was determined by calculating Cramer's V statistic and the contingency coefficient. In both cases, a value near 1 (0.84 and 0.78, respectively) was obtained, indicating a high association between these genotypic screenings. Thus these are complementary, not exclusionary techniques that can be equally applied. CONCLUSIONS: PFGE is a standardized, high-technology molecular tool with considerable discriminatory power. HVR-mecA PCR is a fast, simple, accessible tool that has lower discriminatory power; nonetheless it can serve as an alternative method for epidemiological research in MRSA strains.

Asociación entre los criterios de clasificación genotípica de Staphylococcus aureus resistente a meticilina que se obtuvo mediante electroforesis en geles de campos pulsantes y mediante reacción en cadena de la polimerasa de regiones hipervariables del gen meca / Association between genotype screening results obtained by PFGE and PCR for hypervariable regions of the mecA gene in methicillin-resistant Staphylococcus aureus

Introducción: El Staphylococcus aureus resistente a meticilina (SARM) es un problema epidemiológico en el ámbito mundial. Métodos: Se determinó el grado de asociación entre los criterios de clasificación genotípica que se obtuvieron mediante PFGE (pulsed-field gel electrophoresis‘electroforesis en geles de campos pulsantes’) y PCR (polymerase chain reaction‘reacción en cadena de la polimerasa’) de 7 regiones hipervariables de ácido desoxirribonucleico asociadas al gen mecA (PCR RHV-mecA) que se aplicaron al análisis de 36 cepas de SARM no relacionadas con brotes epidémicos, aisladas de sujetos que ingresaron en el Hospital Regional de Valdivia, Chile. Resultados: Las cepas se clasificaron en 15 pulsotipos (de la A a la O) y en 5 genotipos (6, 14, 15, 16 y 17) según PFGE y PCR RHV-mecA, respectivamente. La mayoría de las cepas se agruparon en los pulsotipos D, E e I que presentaron un porcentaje de similitud del 85,7%. Los genotipos PCR RHV-mecA de mayor frecuencia fueron el genotipo 14 (36,1%) y el genotipo 15 (33,3%). Cada uno de los genotipos detectados mediante PCR RHV-mecA se distribuyó en más de un pulsotipo. El grado de asociación entre los criterios de clasificación genotípica de PFGE y de PCR RHV-mecA se determinó mediante el coeficiente de contingencia y el coeficiente v de Cramer. En ambos se obtuvo un valor cercano a 1 (0,84 y 0,78, respectivamente) que indicaba una alta asociación entre estos criterios, por tanto, se trataría de técnicas complementarias y no excluyentes que pueden aplicarse indistintamente. Conclusiones: La PFGE representa una herramienta molecular de alta tecnología, estandarización y poder discriminatorio; sin embargo, la tipificación por PCR RHV-mecA es una herramienta simple, accesible y rápida que a pesar de su menor poder discriminatorio puede utilizarse como alternativa en estudios epidemiológicos de las cepas de SARM (AU)

Introduction: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a major epidemiological problem worldwide.Methods: We determined the degree of association between the genotype screening results obtained by pulse-field gel electrophoresis (PFGE) and polymerase chain reaction (PCR) for 7 hypervariable DNA regions associated with the mecA gene (HVR-mecA PCR), in the epidemiological analysis of 36 MRSA strains unrelated to nosocomial outbreaks, isolated from hospitalized patients at the County Hospital of Valdivia (Chile).Results: The strains were classified into 15 pulse types (A-O) and 5 genotypes (6, 14, 15, 16, and 17) by PFGE and HVR-mecA PCR, respectively. Most of the strains were grouped in pulse types D, E and I, which presented 85.7% similarity. The most common genotypes were 14 (36.1%) and 15 (33.3%). Each genotype detected by HVR-mecA PCR was distributed in more than one pulse type. The degree of association between genotypic screening by PFGE or HVR-mecA PCR was determined by calculating Cramer's V statistic and the contingency coefficient. In both cases, a value near 1 (0.84 and 0.78, respectively) was obtained, indicating a high association between these genotypic screenings. Thus these are complementary, not exclusionary techniques that can be equally applied. Conclusions: PFGE is a standardized, high-technology molecular tool with considerable discriminatory power. HVR-mecA PCR is a fast, simple, accessible tool that has lower discriminatory power; nonetheless it can serve as an alternative method for epidemiological research in MRSA strains (AU)

[Genotypes of Staphylococcus aureus strains with methicillin resistant phenotype]. / Genotipos de Staphylococcus aureus con fenotipo meticilino resistente, aislados de pacientes del Hospital Base de Valdivia.

BACKGROUND: Methicillin resistant strains of Staphylococcus aureus (MRSA) are an important cause of nosocomial infections. AIM: To determine the genotypes of MRSA strains. MATERIAL AND METHODS: Fifty five strains of MRSA, isolated from patients hospitalized in Hospital Base Valdivia, were studied. The phenotype was determined through MicroScan in all strains and by minimum inhibitory concentration (MIC) in 41. The genotype of the strains was analyzed by a duplex polymerase chain reaction (PCR) of the mecA gene, amplifying eight hypervariable DNA regions associated to such gene. RESULTS: According to MIC, 88% of strains had a pattern of resistance against multiple antimicrobial (penicillin, ampicillin, cephradine, gentamycin, ciprofloxacin, lincomycin and erythromycin). Vancomicin resistan strains were not detected. Only 53 strains (96%) had at least one of the eight hypervariable regions and were classified as MRSA. Genotypic patterns types 15 were the most commonly detected in 38% and 34% of strains, respectively. MicroScan erroneously classified five strains in an incorrect phenotype, according to results obtained with duplex PCR. MIC results did not differ from those of duplex PCR. CONCLUSIONS: Duplex- PCR is a useful tool to detect hyper variable regions associated to mecA gene.

Susceptibility of Arcobacter butzleri to heavy metals

Arcobacter butzleri é um bacilo Gram negativo de caráter zoonótico, pertencente à Família Campylobacteraceae, que tem sido associado a diarréia e septicemia no ser humano. A susceptibilidade de 50 amostras de A. butzleri isoladas de fígados de frango [12], mariscos [18], água de rio [6] e fezes de bovinos [5], patos [2] e pelicanos [7] aos metais pesados mercúrio (Hg), cromo (Cr), prata (Ag), níquel (Ni), cobalto Co), ferro (Fe), manganês (Mn), molibdênio (Mo) e chumbo (Pb) foi determinada.Todas as amostras foram resistentes a Mo, Mn, Ni, Co, Pb e Fe, sendo susceptíveis a Hg, Ag e Cr. Os valores das CIM apresentaram alta variabilidade indicando um comportamento não homogêneo entre as amostras.

Desiccation resistance in Arcobacter butzleri

The desiccation resistance of A. butzleri was studied. Two, 3 and 4 of the strains did not resist desiccation for more than 2, 12 and 36 h, respectively. Two strains resisted desiccation for>=48 h. A butzleri seems to be more resistant to desiccation than the classical enteropathogenic Campylobacter species.