Submitted to: International Association for Fresh Produce
Publication Type: Abstract only
Publication Acceptance Date: 4/1/2005
Publication Date: 8/20/2005
Citation: Zhang, Y., Yeh, E., Shen, Y., Hall, G., Bhagwat, A.A., Meng, J. 2005. Characterization of listeria monocytogenes isolated from deli meats and retail chickens. International Association for Fresh Produce. Interpretive Summary:
Technical Abstract: A total of 167 Listeria monocytogenes isolates were obtained from deli meats, conventional and organic chicken, conventional and organic fresh produce samples. Strain characterization was carried out by serogroup identification and pulsed-field gel electrophoresis (PFGE). A broth microdilution method was followed to test the antimicrobial susceptibility profile of these strains. All isolates obtained belonged to 5 different serogroups. About 41% of the isolates were from serogroup 1/2b, 3b, followed by 32% from serogroup 4b, 4d, 4e, 26% from serogroup 1/2a, 3a, 1.2% from serogroup 1/2c, 3c and 0.6% from serogroup 4a, 4c. The identification of potential serotype 4b from all food categories, especially from organic chicken products, raised a public health concern, because serotype 4b has been the number one serotype associated with clinical isolates. One hundred and six PFGE patterns were identified among all 167 isolates suggesting a very diverse population of L. monocytogenes genotypes. Percentages of resistance to ciprofloxacin, tetracycline, sulfonamide, and nalidixic acid were 1.8%, 9%, 73%, and 100%, respectively. Multiple resistances were observed in 82% of the isolates. These findings indicated that L. monocytogenes in food were diverse and might have originated from difference sources, and that multiresistant L. monocytogenes were present in food products.