title: Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor.
abstract: Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml(-1) reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources.
authors: School of Pharmacy, De Montfort University, Leicester, United Kingdom klaird@dmu.ac.uk.
authors: Katie
authors: K
authors: Laird
authors: School of Pharmacy, De Montfort University, Leicester, United Kingdom.
authors: Elena
authors: E
authors: Kurzbach
authors: The School of Health, The University of Northampton, Northampton, United Kingdom.
authors: Jodie
authors: J
authors: Score
authors: School of Pharmacy, De Montfort University, Leicester, United Kingdom.
authors: Jyoti
authors: J
authors: Tejpal
authors: School of Pharmacy, De Montfort University, Leicester, United Kingdom.
authors: George
authors: G
authors: Chi Tangyie
authors: The School of Health, The University of Northampton, Northampton, United Kingdom.
authors: Carol
authors: C
authors: Phillips
mesh_terms: D000080462:Acyclic Monoterpenes; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D002957:Citrus / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D007875:Legionella / Q000187:drug effects*; D007877:Legionnaires' Disease / Q000382:microbiology / Q000517:prevention & control*; D039821:Monoterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012988:Soil Microbiology; D014871:Water Microbiology
chemical_list: D000080462:Acyclic Monoterpenes; D000890:Anti-Infective Agents; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds; D039821:Monoterpenes; D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils; C010789:beta-pinene; C018584:linalool; C007076:citral