Ciprofloxacin-Resistant Serovar Kentucky ST198 in Broiler Chicken Supply Chain and Patients, China, 2010-2016.

serovar Kentucky (. Kentucky) sequence type 198 has emerged as a global zoonotic pathogen. We explored serovar Kentucky ST198 samples from the broiler chicken supply chain and patients between 2010 and 2016. Here, we collected 180 . Kentucky isolates from clinical cases and the poultry supply chain. We performed pulsed-field gel electrophoresis and multilocus sequence typing. We assessed mutations in the quinolone resistance-determining regions and screened for the presence of the genomic island 1 (SGI1). We determined that 63 (35.0%) of the 180 isolates were . Kentucky ST198. Chinese strains of . Kentucky ST198 have a high transmission of ciprofloxacin resistance (38/63, 60.3%) and a high risk of multidrug resistance. The quinolone resistance of the . Kentucky ST198 strain found in China may be due to mutations in its quinolone resistance-determining region. Our study firstly revealed that ciprofloxacin-resistant . Kentucky ST198 strains can undergo cross-host transmission, thereby causing a serious foodborne public health problem in China.