Abstract: Listeria monocytogenes isolated from chicken meat were characterized for their antimicrobial susceptibility, plasmid profile, chromosomal polymorphism by RAPD fingerprinting using three primers and to determine whether genetic information coding for antimicrobial resistance in Listeria monocytogenes strain may be carried on conjugative R plasmid. A total of 28 strains of Listeria monocytogenes isolated from 12 (60%) of the sample analysed, were resistant to three or more antimicrobial agents tested. However, none of the isolates were resistant to norfloxacin. Twelve (42.87%) of the Listeria monocytogenes strains contained plasmid DNA bands ranging in size from 2.7 to 54 Kb. Combination of the plasmid profiling and antibiogram could separate the strains into different types. In conjugation studies, tetracycline resistance was transferred from the donor strains L. monocytogenes LMC2KLl.6, LMC6Kl4.2 and LMC20S3.4 to the recipient strains L. monocytogenes LMC7KL4.5, LMC21S3.5 and LMC25K2.1 at frequencies of 2.15 x 10-8, 3.58 x 10-9 and 3 x 10-9, respectively. Vancomycin-resistance was transferred to Listeria monocytogenes LMC2KL1.6 strain at frequency of 2.15 x 10-8 and novobiocin-resistance was transferred to Listeria monocytogenes LMC20S3.4 strain at frequency of 3 x 10-9. Our results demonstrate that RAPD-PCR fingerprinting method is more sensitive than plasmid profiling and antibiotic resistance patterns with respect to individualization of the isolates used in this study.
Endang Purwati , Son Radu , Ahmad Ismail , Cheah Yoke Kqueen and Lesley Maurice , 2003. Characterization of Listeria monocytogenes Isolated from Chicken Meat: Evidence of Conjugal Transfer of Plasmid-mediated Resistance to Antibiotic . Journal of Animal and Veterinary Advances, 2: 237-246.