Plant-derived compounds inactivate antibiotic-resistant Campylobacter jejuni strains.
Sixty-three Campylobacter jejuni isolates were screened for their resistance to the antibiotics ampicillin, cefaclor, ciprofloxacin, erythromycin, gentamycin, tetracycline, and trimethoprim-sulfamethoxazole. Based on this screen, the resistant strains D28a and H2a and the nonresistant strain A24a were selected for evaluation of their resistance and susceptibility to inactivation by cinnamaldehyde and carvacrol, the main constituents of plant-derived cinnamon and oregano oils, respectively. Different concentrations (0.05, 0.1, and 0.2% [vol/vol] in sterile phosphate-buffered saline) of cinnamaldehyde and carvacrol were added to C. jejuni cultures with initial populations of 10(4) CFU/ml. The samples were then mixed thoroughly and incubated at 37 degrees C. Viable bacterial populations were enumerated at incubation periods of 0, 30, 60, and 120 min. The results indicate that the extent of inhibition of microbial survival was related to both the nature and concentration of antimicrobials and the incubation time. Both cinnamaldehyde and carvacrol exhibited rapid antimicrobial activity against both antibiotic-resistant and non-resistant C. jejuni strains, at concentrations of approximately 0.1% and higher. The antimicrobial efficacy of cinnamaldehyde was greater than that of carvacrol. The possible significance of the results for microbiological food safety is discussed.
Ravishankar
Sadhana
S
Department of Veterinary Science and Microbiology, University of Arizona, 1117 East Lowell Street, Tucson, Arizona 85721, USA. sadhravi@email.arizona.edu
Zhu
Libin
L
Law
Bibiana
B
Joens
Lynn
L
Friedman
Mendel
M
D000171:Acrolein / Q000031:analogs & derivatives* / Q000494:pharmacology; D016123:Campylobacter jejuni / Q000187:drug effects* / Q000254:growth & development; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D006801:Humans; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000494:pharmacology; D031341:Origanum / Q000737:chemistry; D010938:Plant Oils / Q000494:pharmacology*; D013997:Time Factors
D000081007:Cymenes; D004338:Drug Combinations; D039821:Monoterpenes; D009822:Oils, Volatile; D010938:Plant Oils; D000171:Acrolein; C073316:carvacrol; C012843:cinnamaldehyde