title: Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China.
abstract: Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these results indicated that these H2S-negative isolates may have been prevalent in China. These findings suggested that surveillance should be increased of H2S-negative S. Choleraesuis in China.
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China; Xiangya Basic Medical College, Central South University, Changsha, 410013, China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Yi
authors.affiliation: Clinical Diagnostic Center, 302 Hospital of PLA, Beijing, China.
authors.forename: Jiangong
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China; College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030800, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Liang
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Yang
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Ligui
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Rongzhang
authors.initials: R
authors.lastname: Hao
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Leili
authors.initials: L
authors.lastname: Jia
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Shaofu
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, 100071, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Song
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D006862:Hydrogen Sulfide / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D006862:Hydrogen Sulfide