Effect of sublethal concentrations of ceftriaxone on antibiotic susceptibility of multiple antibiotic-resistant Salmonella strains. Issue 2 (9th January 2019)

• Record Type: Journal Article
• Authors: Zhou, Xiujuan; Zhang, Zengfeng; Suo, Yujuan; Cui, Yan; Zhang, Fen; Shi, Chunlei; Shi, Xianming
• Is Part Of: FEMS microbiology letters. Volume 366:Issue 2(2019)
• Publication Date: 2019-01-09
• Subjects: sublethal -- ceftriaxone -- Salmonella -- AcrAB-TolC -- S1-PFGE; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fny283
• Languages: English
• ISSNs: 0378-1097

Abstract

Abstract: The aim of this study was to determine whether sublethal concentrations of ceftriaxone could alter antibiotic resistance patterns in Salmonella strains. Three multiple antibiotic-resistant S a lmonella isolates and the control strain ATCC 13076 were subjected to induction experiments by stepwise increases in sublethal concentrations of ceftriaxone. Sublethal levels of ceftriaxone induced antibiotic resistance but not control Salmonella isolates to ceftriaxone and to other antibiotics. After 100 generations in 2 months when the antibiotic stress was removed, only one isolate ( Salmonella Typhimurium 11202) maintained the induction changes in antibiotic resistance phenotype (tetracycline from resistance to sensitive and ampicillin from sensitive to resistance). Consistent with its stable phenotypic resistance changes, expression of the tetracycline and β-lactam resistance-related genes tetA and blaTEM were >10-fold down- and upregulated, respectively. Moreover, this strain had increased mRNA levels of efflux pump associated genes acrB and tolC and the SOS response regulator lexA and downregulation of the porin gene ompC . We found no overt changes in plasmid profiles before and after resistance induction. In all, sublethal concentrations of ceftriaxone induced alterations in Salmonella isolates to multiple antibiotics and some of them kept stable maintenance. The increased bla TEM expression may pose a potential danger for new generation β-lactam antibiotics. Abstract : Sub-MIC ceftriaxone levels induced alterations in antibiotic resistance of Salmonella strains, and the induction changes in antibiotic resistance phenotype could be maintained by altering expression of resistance-related genes.