title: Ciprofloxacin-sensitive and ciprofloxacin-resistant Campylobacter jejuni are equally susceptible to natural orange oil-based antimicrobials.
abstract: A total of 10 ciprofloxacin-sensitive (ciprofloxacin minimum inhibitory concentration, MIC < 0.5 micro g/ml) and 10 ciprofloxacin-resistant (MIC 16 to 32 micro g/ml) presumptive C. jejuni were further characterized and evaluated for their inhibition by natural orange oil fractions. Partial species identification was performed by using a hippuricase gene-based polymerase chain reaction (PCR) assay. One of the isolates appeared to be atypical and failed to hydrolyze hippurate. Of the ciprofloxacin-resistant C. jejuni isolates tested, six were found to have their quinolone resistance determined by a C --> T mutation in codon 86 of gyrA. Both groups of ciprofloxacin-sensitive and -resistant C. jejuni isolates were most susceptible to cold-pressed terpeneless Valencia orange oil (C4) which yielded inhibition zones from 44.0 +/- 1.4 to 80 +/- 0.0 mm. Less inhibitory responses were recorded for 5-fold concentrated Valencia orange oil (C3) and distilled d-limonene (C7) which exerted similar effects on both ciprofloxacin-sensitive and -resistant C. jejuni isolates. In general, ciprofloxacin-resistant and -sensitive C. jejuni isolates were equally susceptible to the respective orange oil fractions.
authors.affiliation: Center for Food Safety-IFSE, University of Arkansas, Fayetteville, Arkansas, USA.
authors.forename: R
authors.initials: R
authors.lastname: Nannapaneni
authors.forename: V I
authors.initials: VI
authors.lastname: Chalova
authors.forename: R
authors.initials: R
authors.lastname: Story
authors.forename: K C
authors.initials: KC
authors.lastname: Wiggins
authors.forename: P G
authors.initials: PG
authors.lastname: Crandall
authors.forename: S C
authors.initials: SC
authors.lastname: Ricke
authors.forename: M G
authors.initials: MG
authors.lastname: Johnson
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D016123:Campylobacter jejuni / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002849:Chromatography, Gas; D002939:Ciprofloxacin / Q000494:pharmacology*; D053138:Cyclohexenes / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D000077222:Limonene; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D053138:Cyclohexenes; D010938:Plant Oils; D015363:Quinolones; D013729:Terpenes; D002939:Ciprofloxacin; D000077222:Limonene; C087245:orange oil