Y-020. Antimicrobial Resistance and Genetic Relatedness among Salmonella Schwarzengrund from Slaughtering Broiler and Human

Y-C. Wang1, K-S. Yeh2, Y-C. Chang3,1, T-H. Chen4;
1Natl. Chung Hsing Univ., Taichung, TAIWAN, 2Taipei Med. Univ., Taipei, TAIWAN, 3China Med. Univ., Taichung, TAIWAN, 4The Graduate Inst. of Vet. Pub. Hlth., Natl. Chung Hsing Univ., Taichung, TAIWAN.

Background: Salmonella Schwarzengrund is an infrequent serotype isolated from humans in Taiwan. However, this serotype is highly invasive found in humans reported by two independent epidemiologic surveys. Our previous study delineated the widespread resistance to fluoroquinolone in S. Schwarzengrund isolated from both poultry and swine carcesses in Taiwan. We conducted the present study to investigate the characteristics of S. Schwarzengrund isolated from broiler chicken and human in Taiwan. Methods: Of the 144 S. Schwarzengrund isolates obtained from slaughtering chicken in central Taiwan between June 2006 and March 2007, we tested antimicrobial drug susceptibility and the quinolone resistance determining region sequencing. XbaI PFGE typing were compare with 55 S. Schwarzengrund isolates from human to investigate the epidemiologic relationship among the isolates. Results: 99.3% resistant to multiple (at least three) antimicrobials. Resistance was most often observed to colistin, tetracycline, trimethoprim-sulfamethoxazole, nalidixic acid and ampicillin. All the strains remained susceptible to other beta-lactams. A total of 59 PFGE patterns were observed, and 118 (59.3%) isolates had the closely related PFGE patterns. Six ciprofloxacin-resistant isolates carried tha same five mutations in the QRDR, a double mutation in the QRDR of gyrA, Ser83Phe and Asp87Gly, and a double mutation in the QRDR of parC, Thr57Ser and Ser80Arg. an additional mutation in the QRDR of parE, Ser458Pro. Conclusion: This study indicates that multidrug-resistant S. Schwarzengrund spread widely in chickens and may disseminated from chickens to persons by broiler meat consumption in Taiwan.