Volume 12, Number 2—February 2006
Fluoroquinolone-resistant Salmonella sp. in Carcasses
To the Editor: Fluoroquinolone (FQ)-resistant Salmonella has been isolated from patients in Taiwan (1–7). 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.
- Baucheron S, Chaslus-Dancla E, Cloeckaert A, Chiu CH, Butaye P. High-level resistance to fluoroquinolones linked to mutations in gyrA, parC, and parE in Salmonella enterica serovar Schwarzengrund isolates from humans in Taiwan. Antimicrob Agents Chemother. 2005;49:862–3.
- Chiu CH, Su LH, Hung CC, Chen KL, Chu C. Prevalence and antimicrobial susceptibility of serogroup D nontyphoidal Salmonella in a university hospital in Taiwan. J Clin Microbiol. 2004;42:415–7.
- Chiu CH, Wu TL, Su LH, Chu C, Chia JH, Kuo AJ, The emergence in Taiwan of fluoroquinolone resistance in Salmonella enterica serotype Choleraesuis. N Engl J Med. 2002;346:413–9.
- Chiu CH, Wu TL, Su LH, Liu JW, Chu C. Fluoroquinolone resistance in Salmonella enterica serotype Choleraesuis, Taiwan, 2000–2003. Emerg Infect Dis. 2004;10:1674–6.
- Hsueh PR, Teng LJ, Tseng SP, Chang CF, Wan JH, Yan JJ, Ciprofloxacin-resistant Salmonella enterica Typhimurium and Choleraesuis from pigs to humans, Taiwan. Emerg Infect Dis. 2004;10:60–8.
- Huang TM, Chang YF, Chang CF. Detection of mutations in the gyrA gene and class I integron from quinolone-resistant Salmonella enterica serovar Choleraesuis isolates in Taiwan. Vet Microbiol. 2004;100:247–54.
- Ko WC, Yan JJ, Yu WL, Lee HC, Lee NY, Wang LR, A new therapeutic challenge for old pathogens: community-acquired invasive infections caused by ceftriaxone- and ciprofloxacin-resistant Salmonella enterica serotype Choleraesuis. Clin Infect Dis. 2005;40:315–8.
Suggested citation for this article: Wang Y-C, Yeh K-S, Chang C-C, Hsuan S-L, Chen T-H. Fluoroquinolone-resistant Salmonella sp. in carcasses [letter]. Emerg Infect Dis [serial on the Internet]. 2006 Feb [date cited]. http://dx.doi.org/10.3201/eid1202.050629