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Full Length
Research Paper
Nalidixic acid resistance and clonal expansion of
Salmonella enterica serotype Paratyphi A Isolates in
Yuxi city, China.
W. Shukun1,
C.Congjia2, Y. Yunbo1, K. Biao3,
and D. Baowei3
1Centre
for Disease Control and prevention of Yuxi city, Yuxi
653100, China. 2People，s
Hospital of Yuxi city, Yuxi 653100, China. 3National
Institute for Communicable Disease Control and Prevention,
Chinese Center for Disease Control and Prevention, P.O. Box
5, Changping, Beijing 102206, China.
*Corresponding author E-mail:
yxwsk@hotmail.com
Received 10 April, 2010; Accepted 08 May, 2010
Antimicrobial susceptibility tests were performed with 4060
strains of Salmonella enterica serotype Paratyphi A
(SPA) isolated from patients at Yuxi City from 1999 to 2008.
The incidence of resistance to nalidixic acid of the
isolates increased from 12.5% in 1999 to 82.2% in 2000,
93.0% in 2001, and 100% in 2008. The frequencies of
intermediary and susceptibility (Kirby-Bauer disc diffusion
technique) to ciprofloxacin were 17.0% and 83.0% before
2005, 65.3% and 34.7% in 2008, respectively. A group of 166
NAR and 20 NAS isolates of SPA were typed by pulsed-field
gel electrophoresis (PFGE) using SpeI into nine different
PFGE patterns with predominance of the SpeI01 and SpeI02.
All NAR isolates had higher MICs for fluoroquinolone. We
validate the use of the nalidixic acid screening test for
detection of decreased fluoroquinolone susceptibility in
SPA.
Keywords: Paratyphoid fever, Salmonella enterica
serotype Paratyphi, antimicrobial susceptibility, resistance
to nalidixic acid, PFGE, clonal expansion. |