Identification and Characterization of Conjugative Plasmids That Encode Ciprofloxacin Resistance in Salmonella

Abstract

This study aimed to characterize novel conjugative plasmids that encode transferable ciprofloxacin resistance in In this study, 157 nonduplicated isolates were recovered from food products, of which 55 were found to be resistant to ciprofloxacin. Interestingly, 37 of the 55 Cip isolates (67%) did not harbor any mutations in the quinolone resistance-determining regions (QRDR). Six isolates were shown to carry two novel types of conjugative plasmids that could transfer the ciprofloxacin resistance phenotype to J53 (azithromycin resistant [Azi]). The first type of conjugative plasmid belonged to the ∼110-kb IncFIB-type conjugative plasmids carrying -bearing and-bearing mobile elements. Transfer of the plasmid between and could confer a ciprofloxacin MIC of 1 to 2 μg/ml. The second type of conjugative plasmid belonged to ∼240-kb IncH1/IncF plasmids carrying a single PMQR gene, Importantly, this type of conjugative ciprofloxacin resistance plasmid could be detected in clinical isolates. The dissemination of these conjugative plasmids that confer ciprofloxacin resistance poses serious challenges to public health and infection control.

Quantifying the impact of treatment history on plasmid-mediated resistance evolution in human gut microbiota

“…We assume that the community harbors a conjugative PMQR plasmid which spreads only among gram-negative bacteria, i.e., Proteobacteria and Bacteroidetes. These 2 assumptions reflect the following observations: 1) PMQR genes have been found in a variety of Enterobacteriaceae, especially E. coli and species belonging to the genera Enterobacter, Klebsiella, and Salmonella (61)(62)(63)(64)(65), as well as enteric Bacteroidetes species (66); 2) PMQR genes are usually found on conjugative plasmids (61,63,67,68); and 3) although these genes are found in a variety of gram-positive organisms, they are chromosomal but not plasmid mediated (69,70). As we are interested in the effect of treatment history on plasmid-mediated resistance, we ignore de novo emergence of resistance.…”

Transferable Plasmids of Salmonella enterica Associated With Antibiotic Resistance Genes

“…IncF plasmids have been isolated that contain AR genes. IncF plasmids in Salmonella isolated in China carried fluoroquinolone resistance genes ( Chen et al, 2018 ). IncF plasmids isolated from Salmonella I 4,[5],12:i:-, the monophasic variant of Typhimurium, carried bla TEM-1 , cml A (chloramphenicols), and an integron containing drf A (trimethoprim), aad A1 and aad A2 (aminoglycosides), and sul 3 ( Garcia et al, 2014 ).…”

Transmission of Chromosomal MDR DNA Fragment Encoding Ciprofloxacin Resistance by a Conjugative Helper Plasmid in Salmonella

“…However, ciprofloxacin resistance strains of Salmonella whose resistance phenotypes are transferable have rarely been reported, since the majority of PMQR genes were normally located in non-conjugative plasmid or the chromosome of Salmonella (Lin et al, 2015). However, the ciprofloxacin-resistance phenotype encoded by two types of conjugative plasmids has been reported in Salmonella previously (Chen et al, 2018), suggesting that ciprofloxacin resistance is now readily transferrable. This study identified a chromosomal DNA fragment carrying PMQR and other drug-resistance genes that was assembled via plasmid-mediated integration into the Salmonella chromosome.…”

“…These PMQR determinates are commonly detected in the chromosomes and non-conjugative plasmids in S. Derby. Recently, conjugative ciprofloxacin resistance has been reported, including (1) conjugative plasmids encoding PMQR genes, and (2) helper plasmids mediating transmission of non-conjugative plasmids harboring multiple PMQR determinants, which might accelerate the further dissemination of resistance to ciprofloxacin in Salmonella (Chen et al, 2018(Chen et al, , 2019a.…”