RESUMEN
BACKGROUND: Antibiotic resistant strains of Pseudomonas aeruginosa are the cause of Gram negative nosocomial infections especially among the immunosuppressed patients. The bacteria contains las I and las R genes that play very important roles in the pathogenesis and mechanisms of aggression. These genes can be influenced by the quorum sensing (QS) system and such mechanism is becoming clinically important worldwide. This study aimed to investigate the preventive effects of green coffee extract (GCE) on the expression of pathogenesis-related genes, las I and las R in P. aeruginosa. METHODS: A total of fifty four P. aeruginosa strains were isolated out of 100 clinical samples collected from the infectious wards in different hospitals (Tehran province) using conventional microscopic and biochemical methods. Susceptibility of the isolates to different antibiotics, GCE and chlorogenic acid were elucidated. Multiplex polymerase chain reaction (PCR) and real-time PCR were performed to detect and quantify the expression levels of las I and las R genes. The presence of chlorogenic acid in GCE was confirmed by HPLC. RESULTS: Antibiotic susceptibility tests revealed multidrug resistance among the clinical isolates of those 40 strains were resistant to ciprofloxacin (74.07%), 43 to ceftazidime (79.26%), 29 to amikacin (53.7%), 42 to ampicillin (77.77%), 17 to colistin (31.48%), 40 to gentamicin (74.77%), and 50 to piperacillin (92.59%). PCR outcomes exhibited that the frequency of las I and las R genes were 100% in resistant and sensitive strains isolated from clinical and standard strains of P. aeruginosa (ATCC 15449). Real-time PCR analyses revealed that GCE significantly prevented the expression of las I and las R genes in P. aeruginosa. GCE at concentration level as low as 2.5 mg/mL could prevent the expression of lasI and lasR genes in P. aeruginosa clinical isolates. CONCLUSION: The presence and expression levels of las I and las R genes in P. aeruginosa isolates were investigated when the bacteria was exposed to GCE. Our results tend to suggest that genes involved in pathogenesis of:Pseudomonas aeruginosa are down regulated by quorum sensing effect of chlorogenic acid and therefore GCE could be useful as an adjuvant in combating multidrug resistance strains of Pseudomonas aeruginosa.
Asunto(s)
Proteínas Bacterianas/genética , Café/química , Extractos Vegetales/farmacología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/patogenicidad , Transactivadores/genética , Antibacterianos/química , Antibacterianos/farmacología , Ácido Clorogénico/aislamiento & purificación , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/microbiología , Regulación hacia Abajo , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/química , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Percepción de Quorum/efectos de los fármacos , Virulencia/efectos de los fármacosRESUMEN
Ferulago carduchorum (Apiaceae family) is an endemic plant of Iran. The crude extract and four fractions of aerial parts of F. carduchorum in two vegetative stages (flower and fruit) were studied for their total phenolic contents, antimicrobial and antioxidant activities using folin-ciocalteu assay, micro dilution method and DPPH assay, respectively. The results indicated that the best antioxidant activity was determined in flower crude extract (IC50=0.44 mg/mL). The flower ethyl acetate fraction (FLE) showed better antimicrobial and antifungal activities than other fractions. So, FLE was selected for phytochemical investigations, resulting in isolation of a flavonoid (hesperetin). Hesperetin showed antimicrobial activity. The results showed that the antimicrobial and antioxidant effects during the flowering are obviously more than the fruit season.
Asunto(s)
Antiinfecciosos/farmacología , Antioxidantes/farmacología , Apiaceae/química , Hesperidina/farmacología , Fenoles/farmacología , Extractos Vegetales/farmacología , Antiinfecciosos/aislamiento & purificación , Antioxidantes/aislamiento & purificación , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , Compuestos de Bifenilo/química , Flores , Frutas , Hongos/efectos de los fármacos , Hongos/crecimiento & desarrollo , Hesperidina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Fenoles/aislamiento & purificación , Fitoterapia , Picratos/química , Extractos Vegetales/aislamiento & purificación , Plantas Medicinales , Solventes/químicaRESUMEN
The antimicrobial activity of ethanol and chloroform extracts of Pentanema divaricatum Cass. was studied using the conventional disk diffusion method. The extracts' highest antimicrobial activity was observed against Aspergillus niger. Bioassay-guided fractionation of the crude extract by preparative thin layer chromatography (PTLC) showed one antimicrobial fraction which was especially effective against Aspergillus niger. By conventional spectroscopy the active fraction was identified as 4alpha,5alpha-epoxy-10alpha,14H-1-epi-inuviscolide. This compound represented the most potent antimicrobial candidate, with MIC values of <25 microg/disk against A. niger strains and 200 microg/disk against Bacillus cereus and Staphylococcus aureus.