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

Abstract

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.

Antibiotic Resistance of Salmonella Typhimurium Monophasic Variant 1,4,[5],12:i:-in China: A Systematic Review and Meta-Analysis

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/antibiotics11040532/s1, Table S1: List and characteristics of the 19 eligible studies [13,16,30,[34][35][36]40,48,58,[62][63][64][65][66][67][68][69][70][71].…”

“…The fluoroquinolone resistance-conferring genes qnrS1 and aac(6 )lb-cr have been detected in MDR isolate S. 1,4, [5],12:i:-in Australia [38]. Extended-spectrum β-lactamase-encoding resistance genes (i.e., bla CTX-M-1 , bla CTX-M-14 ) in S. 1,4, [5],12:i:-have been reported for isolates found in Germany and China [39,40], whereas plasmid-mediated colistin resistance genes, i.e., mcr-1 and mcr-3, have been reported for isolates found in Switzerland, Australia, and China [38,41,42]. The aspects of the prevalence of antibiotic-resistant phenotypes in isolates from different sources, levels of antibiotic resistance, or MDR profiles in isolates S. 1,4, [5],12:i:-have been individually studied and documented in many different countries; however, there is a paucity in the literature of combinations of the various aspects mentioned in the context of China.…”