Composición química y actividad antibacteriana del aceite esencial de Peperomia acuminata de los Andes venezolanos / Chemical composition and antibacterial activity of essential oil Peperomia acuminata from Venezuelan Andes

El género Peperomia (Piperaceae), es bien conocido por sus especies ornamentales y usos etnomedicinales. En el presente trabajo se describe la caracterización química y la actividad antibacteriana del aceite esencial de Peperomia acuminata Ruiz & Pav. proveniente del Estado Mérida Venezuela. El aceite esencial se obtuvo por hidrodestilación de las hojas y la separación de los componentes se realizó por Cromatografía de gases-Espectrometría de Masas (CG/EM). Se logró la elucidación de ocho compuestos (96,7%), siendo el 2E-dodecenal el componente mayoritario (65%) seguido de dodecanal (14,8%) y tetradecanal (9,2%). Esta investigación muestra el potencial del aceite esencial de P. acuminata frente a bacterias Gram positivas (Staphylococcus aureus ATCC 25923 y Enterococcus faecalis 29212), con un valor de Concentración inhibitoria mínima de 1μL/mL. Este es el primer reporte sobre la composición química del aceite esencial de esta especie, por lo tanto una contribución importante al estudio del género Peperomia.

The genus Peperomia (Piperaceae) is well known for its ornamental species and ethnomedicinal uses. This paper aims to chemically characterize the essential oil of Peperomia acuminata Ruiz & Pav. from Mérida State, Venezuela, and determine its microbiological activity. The essential oil is obtained by hydrodistillation of the leaves and the separation of the components was performed by gas chromatography-mass spectrometry (GC/MS). Eight compounds (96.7%) were elucidated in the oil. The 2E dodecenal was found to be the major component (65%) followed by dodecanal (14.8%) and tetradecanal (9.2%). The essential oil showed high specificity against Gram positive bacteria Staphylococcus aureus ATCC (25923) and Enterococcus faecalis (29212) with a Minimum Inhibitory Concentration of 1 µL/mL. This is the first report about chemical composition of the essential oil from this specie therefore an important contribution to the study of the genus Peperomia.

Chemical composition of the essential oil from the leaves of Carapa guianensis collected from Venezuelan Guayana and the antimicrobial activity of the oil and crude extracts.

The essential oil obtained by hydrodistillation of Carapa guianensis Aubl. (Meliaceae) leaves was analyzed by GC-FID and GC-MS. Twenty-three components were identified, which made up 93.7% of the oil. The most abundant constituents were bicyclogermacrene (28.5%), alpha-humulene (17.2%), germacrene B (11.9%), and trans-beta-caryophyllene (9.9%). Antimicrobial activity of the essential oil, as well as the crude extracts of the leaves obtained by refluxing the dried leaves with n-hexane, dichloromethane, and methanol, was determined using the disc diffusion assay. Activity against Staphylococcus aureus ATCC 29923 and Enterococcus faecalis ATCC 29212 was only found for the essential oil and the methanolic extract, at minimal inhibitory concentrations (MIC) of 400 microg/mL and 50 microg/mL.

Chemical composition and antibacterial activity of the essential oil of Lantana camara var. moritziana.

The essential oil obtained from the leaves of Lantana camara var. moritziana (Otto & Dietr.) López-Palacios collected at Rubio, Táchira State, Venezuela, was obtained by hydrodistillation in a Clevenger trap (0.1% yield). The oil was analyzed by gas chromatography-mass spectrometry (GC/MS) on HP GC-MS System, model 5973, identifying 33 compounds (97.1%) of which the major components were germacrene D (31.0%), followed by beta-caryophyllene (14.8%), a-phellandrene (6.7%), limonene (5.7%) and 1,8-cineole (5.2%). Evaluation of the antibacterial activity by agar diffusion method with discs against international reference bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Salmonella Typhi, Pseudomonas aeruginosa) showed growing inhibition of E. faecalis and S. aureus at MIC of 350 mg/mL and 400 mg/mL, respectively.

Chemical composition and in vitro antibacterial activity of the essential oil of Phthirusa adunca from Venezuelan Andes.

In this paper, preliminary studies on the chemical characterization of Phthirusa adunca Meyer essential oil, obtained by hydrodistillation, is presented. The separation of the components was performed by GC-MS. Twenty-three compounds (94.5% of the sample) were identified of which the three major ones (76% of the sample) were beta-phellandrene (38.1%), germacrene D (26.8%) and beta-pinene (11.5%). The essential oil showed a broad spectrum of activity against Salmonella Typhi CDC 57 (100 microg/mL), Staphylococcus aureus ATCC 25923 (200 microg/mL), Enterococcus faecalis ATCC 29212 (250 microg/mL), Escherichia coli ATCC 25922 y Klebsiella pneumoniae ATCC 23357 (500 microg/mL). This is the first report on the composition and activity of the essential oil of this species.

CTX-M-14 ß-lactamase-producing Citrobacter freundii isolated in Venezuela.

A clinical isolate of C. freundii with reduced susceptibility to extended-spectrum ß-lactams from a woman with cystocele associated with recurrent urinary tract infection was analyzed. Susceptibility tests, double disk synergy tests (DDST) and enzymatic activity by the agar iodometric method suggested the presence of ESBLs. Conjugation experiments revealed the presence of a large conjugative plasmid (pLM07/20) with an exclusive FrepB replicon type (IncF/FIB). PCR analysis and sequencing confirmed the presence of the blaCTX-M-14 gene in the pLM07/20 from C. freundii.LM07/10. Although this is the first report of CTX-M-14 in Venezuela, we alert the medical community that future increase of these ß-lactamases in our city could be due to dissemination of plasmids into bacterial populations.

Profiles of enteropathogens in asymptomatic children from indigenous communities of Mérida, Venezuela.

INTRODUCTION: In Latin America, gastrointestinal infections represent one of the main causes of death among indigenous groups, with a mortality rate three times greater than in the general population. In this study, the carrier state of enteropathogens and the epidemiological risk factor in asymptomatic children from indigenous communities of Mérida, Venezuela, were determined. METHODOLOGY: Fifty-eight healthy children, 5 years of age and under, were clinically and epidemiologically evaluated. Fecal samples were tested for a range of classic enteropathogens. Antimicrobial susceptibility tests (AST) were performed by dilution methods. RESULTS: Of the specimens studied, there were 34 (58.6%) positive samples, and a single enteropathogen was detected in 22 (64.6%) of these. Associations of two and three enteropathogens were observed in 10 (29.3%) and two (5.8%) cases, respectively. Blastocystis hominis (16; 47.0%) and Salmonella spp. (15; 43.9%) were the most frequently detected enteropathogens. Carriage of enteropathogens was most frequent in children older than two years. The variety of food in the daily diet was the risk factor strongly associated with the presence of parasites and/or enteric bacteria (p = 0.024 < 0.05 and p = 0.000 < 0.05, respectively). The majority of these bacteria were susceptible to the antibiotics tested in vitro. CONCLUSION: This study shows a high prevalence of enteropathogen carriage in asymptomatic children aged five and under from indigenous communities; this result is statistically related to the consumption of food. These findings stress the need of continuous epidemiological surveillance in vulnerable populations, as an important step to prevent the morbidity and mortality due to gastrointestinal infections.

Chemical composition and antibacterial activity of the essential oil of Cordia verbenacea from the Venezuelan Andes.

The essential oil of Cordia verbenacea D.C. (Boraginaceae) that grows in Mérida-Venezuela was obtained by hydrodistillation from the aerial parts of the plant, yielding 0.21%. The oil was analyzed by GC-FID and GC-MS. Thirty one components which made up 94.3% of the oil were identified. The most abundant constituents found were: tricyclene (23.9%), bicyclogermacrene (11.7%), germacrene D (9.9%) and beta-caryophyllene (8.2%). Antibacterial activity determination was carried out according to the disc diffusion assay. Activity against Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212, at a minimal inhibitory concentration (MIC) of 170 microg/mL and 200 microg/mL, was found.

[Comparison between culture media and procedures to detect Streptococcus agalactiae in pregnant women]. / Comparación de medios de cultivos y procedimientos para detectar colonización por Streptococcus agalactiae en mujeres embarazadas.

Detection of Streptococcus agalactiae in pregnant women's vagina and rectum and intrapartum antibiotic prophylaxis administered to colonized women are currently recommended to prevent neonatal precocious infections by this organism. In turn, it is very important to select the culture media and adequate sample collection site for S. agalactiae detection in colonized women. To standardize this methods in laboratory, different culture media and procedures for S. agalactiae recovery in pregnant women with obstetric and gynecologic complications were compared. Vaginorectal and endocervical swab specimens were collected from 60 pregnant women. The first sample was placed onto selective Columbia blood agar directly and onto selective Todd-Hewitt broth incubated at 37 degrees C and subcultured onto selective Columbia blood agar at 4 and 18 hours. The second sample was cultured on selective Columbia blood agar. Both culture media were incubated in a microaerophilic atmosphere at 37 degrees C from 24 to 48 hours. S. agalactiae was identified using conventional tests. 21 patients colonized with S. agalactiae were detected using vaginoanorectal samples. 19 (31.7%) patients tested positive for S. agalactiae through the culture of specimens directly onto selective Columbia blood agar; 21 (35%) and 20 (33%) patients were found to be positive for S. agalactiae by the selective Todd-Hewitt broth at 4 and 18 hours, respectively. Only one patient tested positive for S. agalactiae in the endocervical tract. The results show that the three procedures followed for S. agalactiae recovery are effective. Nevertheless, the procedure in which the sample was placed directly onto selective Columbia blood agar permits reducing costs and the time for bacteria identification. On the other hand, the vaginoanorectal swab was the best sample to detect colonization by S. agalactiae in pregnant women.

Comparación de medios de cultivos y procedimientos para detectar colonización por Streptococcus agalactiae en mujeres embarazadas / Comparison between culture media and procedures to detect Streptococcus agalactiae in pregnant women

Introducción: La detección de Streptococcus agalactiae en la vagina y/o el recto de las mujeres embarazadas y la administración de profilaxis antimicrobiana intraparto en las colonizadas, es el método recomendado para prevenir la infección neonatal precoz por este patógeno. En consecuencia, es importante seleccionar los medios de cultivos y el sitio de toma de muestra más adecuado para la detección de S. agalactiae en mujeres colonizadas. Objetivo: Comparar diferentes medios de cultivos y procedimientos para la recuperación de S. agalactiae en mujeres embarazadas con complicaciones gineco-obstétricas. Metodología: Se tomaron hisopados vagino-ano-rectales y endocer-vicales de 60 mujeres embarazadas. Con la primera muestra se realizó cultivo directo en agar sangre Columbia selectivo (ASCSD), y caldo selectivo Todd Hewitt (CSTH) incubados a 37 °C, y subcultivos a las 4 y 18 horas en agar sangre Columbia selectivo (ASCS). La segunda muestra se cultivó en ASCS. El ASCSD y ASCS se incubaron en atmósfera microaeróñla a 37 °C durante 24 a 48 horas. La identificación de S. agalactiae se realizó mediante pruebas convencionales. Resultados: Utilizando hisopado vagino-ano-rectal se detectaron 21 pacientes colonizadas con S. agalactiae, de la siguiente manera: 19(31,7 por ciento) en el ASCSD, 21 (35 por ciento) en el CSTH a las 4 horas y 20 (33,3 por ciento) a las 18 horas. De las 21 pacientes colonizadas sólo a una paciente se le detectó S. agalactiae en la muestra de secreción vagino-ano-rectal y endocervical simultáneamente. Conclusión: Los tres procedimientos ensayados presentaron igual efectividad para la recuperación de S. agalactiae; sin embargo, con el uso del ASCSD, se disminuyen los costos y el tiempo de identificación de dicho microorganismo. Por otra parte, el hisopado vagino-ano-rectal resultó ser la muestra más idónea para detectar colonización por S. agalactiae en mujeres embarazadas.

Detection of Streptococcus agalactiae in pregnant women's vagina and rectum and intrapartum antibiotic prophylaxis administered to colonized women are currently recommended to prevent neonatal precocious infections by this organism. In turn, it is very important to select the culture media and adequate sample collection site for S. agalactiae detection in colonized women. To standardize this methods in laboratory, different culture media and procedures for S. agalactiae recovery in pregnant women with obstetric and gynecologic complications were compared. Vaginorectal and endocervical swab specimens were collected from 60 pregnant women. The first sample was placed onto selective Columbia blood agar directly and onto selective Todd-Hewitt broth incubated at 37 °C and subcultured onto selective Columbia blood agar at 4 and 18 hours. The second sample was cultured on selective Columbia blood agar. Both culture media were incubated in a microaerophilic atmosphere at 37 °C from 24 to 48 hours. S. agalactiae was identified using conventional tests. 21 patients colonized with S. agalactiae were detected using vaginoanorectal samples. 19 (31.7 percent) patients tested positive for S. agalactiae through the culture of specimens directly onto selective Columbia blood agar; 21 (35 percent) and 20 (33 percent) patients were found to be positive for S. agalactiae by the selective Todd-Hewitt broth at 4 and 18 hours, respectively. Only one patient tested positive for S. agalactiae in the endocervical tract. The results show that the three procedures followed for S. agalactiae recovery are effective. Nevertheless, the procedure in which the sample was placed directly onto selective Columbia blood agar permits reducing costs and the time for bacteria identification. On the other hand, the vaginoanorectal swab was the best sample to detect colonization by S. agalactiae in pregnant women.