title: Neem (Azadirachta indica A. Juss) Oil to Tackle Enteropathogenic Escherichia coli.
abstract: Neem (Azadirachta indica A. Juss) oil (NO) was assayed against forty-eight isolates of Escherichia coli by standardised disc diffusion test and microdilution test. By molecular biology characterization, fourteen isolates resulted in diarrheagenic E. coli with sixteen primer pairs that specifically amplify unique sequences of virulence genes and of 16S rRNA. The NO showed biological activity against all isolates. The bacterial growth inhibition zone by disc diffusion method (100 µL NO) ranged between 9.50 ± 0.70 and 30.00 ± 1.00 mm. The antibacterial activity was furthermore determined at lower NO concentrations (1 : 10-1 : 10,000). The percent of growth reduction ranged between 23.71 ± 1.00 and 99.70 ± 1.53. The highest bacterial growth reduction was 1 : 10 NO concentration with 50 µL of bacterial suspension (ca. 1 × 10(6) CFU/mL). There is significant difference between the antibacterial activities against pathogenic and nonpathogenic E. coli, as well as NO and ciprofloxacin activities. Viable cells after the different NO concentration treatments were checked by molecular biology assay using PMA dye. On the basis of the obtained results, NO counteracts E. coli and also influences the virulence of E. coli viable cells after NO treatment. The NO metabolomic composition was obtained using fingerprint HPTLC.
authors.affiliation: Agricultural Research Council (CRA), Animal Production Research Centre (CRA PCM), Via Salaria 31 Km 26.700, 00015 Monterotondo, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Del Serrone
authors.affiliation: Department of Environmental Biology, University of Rome Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Chiara
authors.identifier: 0000-0001-7059-771X
authors.initials: C
authors.lastname: Toniolo
authors.affiliation: Department of Environmental Biology, University of Rome Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Nicoletti
mesh_terms: D031601:Azadirachta / Q000737:chemistry; D054308:Enteropathogenic Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D005989:Glycerides / Q000008:administration & dosage* / Q000737:chemistry; D006801:Humans; D008826:Microbial Sensitivity Tests; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D013729:Terpenes / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D005989:Glycerides; D012336:RNA, Ribosomal, 16S; D013729:Terpenes; C002443:neem oil