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. 2010 Jan 30:10:32.
doi: 10.1186/1471-2180-10-32.

Genetic diversity of Salmonella enteric serovar typhi and paratyphi in Shenzhen, China from 2002 through 2007

Weiyuan Wu  1 , Hui Wang, Jian Lu, Jinsong Wu, Minjun Chen, Yingchun Xu, Yuemei Lu
Affiliations

Genetic diversity of Salmonella enteric serovar typhi and paratyphi in Shenzhen, China from 2002 through 2007

Weiyuan Wu et al. BMC Microbiol. .

Abstract

Background: Typhoid and paratyphoid fever are endemic in China. The objective of this investigation was to determine the molecular features of nalidixic acid-resistant Salmonella enteric serovar Typhi (S. typhi) and Paratyphi (S. paratyphi) from blood isolates in Shenzhen, China.

Results: Twenty-five S. typhi and 66 S. paratyphi were isolated from 91 bacteremic patients between 2002 and 2007 at a hospital in Shenzhen, Southern China. Fifty-two percent (13/25) of S. typhi and 95.3% (61/64) of S. paratyphi A were resistant to nalidixic acid. Sixty-seven isolates of nalidixic acid-resistant Salmonella (NARS) showed decreased susceptibility to ciprofloxacin (MICs of 0.125-1 microg/mL). All 75 NARS isolates had a single substitution in the quinolone resistance-determining region (QRDR) of GyrA (Ser83-->Phe/Pro/Tyr, or Asp87-->Gly/Asn), and 90.7% of these isolates carried the substitution Ser83Phe in GyrA. No mutation was found in the QRDR of gyrB, parC, or parE. Plasmid mediated quinolone resistance genes including qnr and aac(6')-Ib-cr were not detected in any isolate. Twenty-two distinct pulsed field gel electrophoresis (PFGE) patterns were observed among S. typhi. Sixty-four isolates of S. paratyphi A belonged to one clone. Eighty-seven investigated inpatients were infected in the community. Six patients infected by S. paratyphi A had a travel history before infection.

Conclusions: Nalidixic acid-resistant S. typhi and S. paratyphi A blood isolates were highly prevalent in Shenzhen, China. PFGE showed the variable genetic diversity of nalidixic acid-resistant S. typhi and limited genetic diversity of nalidixic acid -resistant S. paratyphi A.

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Figures

Figure 1
Figure 1
Dendrogram for the S. typhi isolates with distinct PFGE types. Genetic similarity was calculated by the Dice coefficients. R, Resistant; S, Susceptible.
Figure 2
Figure 2
Dendrogram for the S. paratyphi A isolates with the same PFGE types. Genetic similarity was calculated by the Dice coefficients. R, Resistant; S, Susceptible.
Figure 3
Figure 3
Analysis of S. paratyphi A isolates by PFGE of XbaI restriction digests. H standard strain H9812; isolates 44, 45, 48-54 (PFGE type A); isolates 43, 46 (PFGE type A1); isolates 47 and 55 (PFGE type A2).
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References

    1. Parry CM, Hien TT, Dougan G, White NJ, Farrar JJ. Typhoid fever. N Engl J Med. 2002;347:1770–82. doi: 10.1056/NEJMra020201. - DOI - PubMed
    1. Parry CM. The treatment of multidrug resistant and nalidixic acid resistant typhoid fever in Vietnam. Trans R Soc Trop Med Hyg. 2004;98:413–22. doi: 10.1016/j.trstmh.2003.10.014. - DOI - PubMed
    1. Gay K, Robicsek A, Strahilevitz J, Park CH, Jacoby G, Barrett TJ, Medalla F, Chiller TM, Hooper DC. Plasmid-mediated quinolone resistance in non-Typhi serotypes of Salmonella enterica. Clin Infect Dis. 2006;43:297–304. doi: 10.1086/505397. - DOI - PubMed
    1. Xia S, Hendriksen RS, Xie Z, Huang L, Zhang J, Guo W, Xu B, Ran L, Aarestrup FM. Molecular characterization and antimicrobial susceptibility of Salmonella from infections in humans in Henan province, China. J Clin Microbio. 2009;47:401–9. doi: 10.1128/JCM.01099-08. - DOI - PMC - PubMed
    1. Clinical and Laboratory Standards Institute. Approved standard M7-A7. 7. Clinical and Laboratory Standards Institute, Wayne, PA; 2006. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically.

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