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Volume 12, Number 2—February 2006

Fluoroquinolone-resistant Salmonella sp. in Carcasses

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To the Editor: Fluoroquinolone (FQ)-resistant Salmonella has been isolated from patients in Taiwan (17). Recently, a report further indicated that several patients were infected with Salmonella enterica serovar Schwarzengrund with high-level FQ resistance (1). S. Schwarzengrund has never been isolated from food animals in Taiwan.

We report the isolation of FQ-resistant strains from pork and broiler carcasses sampled from 2000 to 2003: 27 in 2000, 3 in 2001, 4 in 2002, and 2 in 2003. These isolates made up 18.85% of the 191 Salmonella strains obtained from pork and broiler carcasses in the study period. Of these isolates, 16 FQ-resistant S. Schwarzengrund strains were further analyzed to elucidate the possible mechanism of FQ resistance. Ciprofloxacin MIC levels in these isolates ranged from 4 to 16 μg/mL, and all had high-level nalidixic acid resistance (>1,024 μg/mL). All of the 16 investigated strains displayed mutations possibly associated with high-level FQ resistance. The mutation sites included 2 sites (Ser83Phe and Asp87Gly) in the quinolone resistance–determining region (QRDR) of gyrA, 2 sites (Thr57Ser and Ser80Arg) in the QRDR of parC, and 1 site (Ser458Pro) in the QRDR of parE, respectively. Four strains had mutations in the QRDR of gyrA and parC only but not in the QRDR of parE (Table).

In conclusion, high-level FQ resistance was detected in S. Schwarzengrund isolated from pork and chicken in Taiwan. Specific mutation sites of gyrA, parC, and parE were associated with high-level FQ resistance in all the isolates investigated. Our results warrant further investigation of the public health consequences of FQ use in food animals in Taiwan.


Yu-Chih Wang*, Kuang-Sheng Yeh†, Chao-Chin Chang*, Shih-Ling Hsuan*, and Ter-Hsin Chen*Comments to Author 
Author affiliations: *National Chung Hsing University, Taichung, Taiwan; †Taipei Medical University, Taipei, Taiwan



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Cite This Article

DOI: 10.3201/eid1202.050629

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Table of Contents – Volume 12, Number 2—February 2006


Please use the form below to submit correspondence to the authors or contact them at the following address:

Ter-Hsin Chen, The Graduate Institute of Veterinary Public Health, College of Veterinary Medicine, National Chung Hsing University, No. 250, Kuo Kuang Rd, Taichung 402, Taiwan; fax: 886-4-2285-2186

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