Prevalence, resistance, and extended-spectrum beta-lactamases among Salmonella from patients in northeast China

  • Zhijie Zhang China Medical University, Shenyang, China
  • Xingning Wang Yanan University, Yanan, China
  • Ruihua Li Dalian Medical University, Dalian, China
  • Wencheng Xue The Clinical Laboratory of the Army General Hospital of Shenyang Military Region of the People’s Liberation Army, Shenyang, China
  • Rubo Zhai The Clinical Laboratory of Chinese People’s Liberation Army 202nd Hospital, Shenyang, China
  • Liwen Liu The Clinical Laboratory of Liaoning Province Hospital, Shenyang, China
  • Yong Liu China Medical University
  • Hong Jin China Medical University, Shenyang, China
Keywords: Salmonella, antimicrobial resistance, cephalosporin


Introduction: Salmonella is an important infection in Liaoning Province. Serotype and resistance levels are poorly studied. Knowledge of cephalosporin-resistant genes is needed to provide information to support the clinical diagnosis and to guide therapy.

Methodology: A total of 172 isolates were collected from January 2009 to March 2014. Resistance to cephalosporin, fluoroquinolones, and other conventional first-line antibiotics was detected using the disk diffusion and agar dilution methods. The relatedness of isolates with the same serotype was analyzed by pulsed-field gel electrophoresis (PFGE). Genes encoding extended-spectrum β-lactamase enzymes (blaCTX-M, blaTEM, blaSHV, and blaOXA) were identified by polymerase chain reaction (PCR) and sequencing in cephalosporin-resistant strains.

Results: S. Enteritidis, 1,4,[5],12:i:-, and S .Typhimurium were the most common serotypes. The resistance rate of Salmonella to conventional first-line antibiotics sulfamethoxazole-trimethoprim, tetracycline, chloramphenicol, and ampicillin was 21%,33%,37%, and 55%,respectively. To fluoroquinolones (gatixacin, levofloxacin, and ciprofloxacin), the resistance rates were 7%,18%, and 23%, respectively, whereas for extended-spectrum cephalosporins(ceftazidime, cefepime, and ceftriaxone), there sistance rates were 4%,8%, and 9%. In total, 14blaCTX-M, 14 blaTEM-1, and 1blaOXA-1 were found in 15 Salmonella isolates resistant to cephalosporin. No blaSHVwas detected. The blaCTX-M-55 gene was the most frequently encountered gene. The blaCTX-M-65 gene from S. Enteritidis is described for first time in Salmonella from humans. Results of PFGE indicated strong similarity among Salmonella isolates in Liaoning Province.

Conclusions: Extended-spectrum cephalosporins are the first choice for the treatment of infection with Salmonella, but blaCTX-M-encoded resistance, including blaCTX-M-65, is present.

Author Biographies

Zhijie Zhang, China Medical University, Shenyang, China

Department of Microbiology and Parasitology

Xingning Wang, Yanan University, Yanan, China

the Clinical Laboratory of Affiliated Hospital

Ruihua Li, Dalian Medical University, Dalian, China

The Clinical Laboratory of Second Hospital.

Yong Liu, China Medical University

The Clinical Laboratory of Shengjing Hospital

Hong Jin, China Medical University, Shenyang, China

I am a Professor from Department of Microbiology and Parasitology of China Medical University. My specialties is resistance mechanism of bacteria and fundamental research of virus.

How to Cite
Zhang Z, Wang X, Li R, Xue W, Zhai R, Liu L, Liu Y, Jin H (2017) Prevalence, resistance, and extended-spectrum beta-lactamases among Salmonella from patients in northeast China. J Infect Dev Ctries 11:470-478. doi:
Original Articles