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Volume 46, Number 6, December 2013

First isolation of ciprofloxacin-resistant Salmonella enterica serovar Typhi in Taiwan 


Chia-Jie Lee, Lin-Hui Su, Yhu-Chering Huang, Cheng-Hsun Chiu


Received: December 25, 2012    Revised: January 9, 2013    Accepted: March 6, 2013   

 

Corresponding author:

Cheng-Hsun Chiu
Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan
Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
Corresponding Author InformationCorresponding author. Department of Pediatrics, Chang Gung Children's Hospital, Number 5, Fu-Hsin Street, Kweishan 333, Taoyuan, Taiwan.

Lin-Hui Su,
Department of Laboratory Medicine, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan
Corresponding Author InformationCorresponding author. Department of Laboratory Medicine, Chang Gung Memorial Hospital, Number 5, Fu-Hsin Street, Kweishan 333, Taoyuan, Taiwan. 



 

Background and purpose: 

Typhoid fever is a major cause of disease burden in developing countries. The use of fluoroquinolones, once considered the drugs of choice, should be re-evaluated due to the emergence of quinolone-resistant Salmonella enterica serovar Typhi. In Taiwan, typhoid fever is rare but constitutes an important public health concern. 



 

Methods:

In August 2011, two ciprofloxacin-resistant S. Typhi isolates were identified from one patient who had recently travelled to India. The two isolates together with four other ciprofloxacin-susceptible S. Typhi isolates were subjected for molecular investigation. Polymerase chain reaction (PCR) and sequencing were used to analyze the resistance mechanisms. Pulsed-field gel electrophoresis (PFGE) was performed to delineate the genetic relatedness among the isolates.
 



 

Results:

In 2011, a total of 49 typhoid fever cases were reported to the Center for Disease Control in Taiwan, with a significant increase in indigenous cases in northern Taiwan from August to November. In the two S. Typhi isolates with complete resistance to ciprofloxacin [minimum inhibitory concentration (MIC) >32 μg/mL], multiple point mutations in the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes were identified. A unique PFGE pattern was found in the resistant isolates and was different from the other representative susceptible isolates. 



 

Conclusion:

The first ciprofloxacin-resistant S. Typhi infection in Taiwan is reported. The emergence and spread of antimicrobial-resistant S. Typhi infection as a result of international travel may become a threat to public health in Taiwan. Clinicians should be well alert when treating patients who may have acquired resistant infections associated with international travel among endemic regions. 



 

Key words:

Ciprofloxacin resistance, International travel, Quinolone resistance-determining regions, Salmonella enterica serovar Typhi