Epidemiological characteristics and clinical treatment outcome of typhoid fever in Ningbo China, 2005-2014, PFGE results revealing great proportion of common transmission sources


Song Q, Yang Y, Lin W, Yi B, Xu G


We aimed to describe the molecular epidemiological characteristics and clinical treatment outcome of typhoid fever in Ningbo, China, 2005-2014. Eighty-eight Salmonella Typhi isolates were obtained from 307 admitted patients. Three prevalent pulsed-field gel electrophoresis (PFGE) patterns of 54 isolates in 3 outbreaks were identified. Overall, there were 64 (72.7%) isolates from cases in clusters and 24 (27.3%) isolates from sporadic cases. Resistance to nalidixic acid (n=47; 53.4%) and ampicillin (n=40; 45.4%) and rare resistance to tetracycline (n=2; 2.3%) and gentamicin (n=2; 2.3%) were observed. Isolates resistant to cefotaxime, chloramphenicol, ciprofloxacin and trimethoprim-sulfamethoxazole (SXT) were not found. The occurrence of reduced sensitivity to ciprofloxacin was 52.2% (n=46). The medians of fever clearance time in cases with complications and cases without complications were 7 (IQR: 4-10) and 5 (IQR: 3-7) days (P=0.001), respectively, when cases were treated with ciprofloxacin or levofloxacin and/or third-generation cephalosporins. The rates of serious complications were at low levels: i.e., peritonitis (2.3%), intestinal hemorrhage (6.8%), and intestinal perforation (1.1%). Present study exhibits clustering trend over long-term periods in terms of clustering PFGE patterns, occasional outbreaks and rapid spread of ampicillin resistance and decreased ciprofloxacin susceptibility among S. Typhi isolates in recent years.

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