Phylogeny and Comparative Genomics Unveil Independent Diversification Trajectories of qnrB and Genetic Platforms within Particular Citrobacter Species

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Ribeiro, TG (Author) Other; Novais, A (Author) Other; Branquinho, R (Author) Other; Machado, E (Author) Other; Luisa Peixe (Author) FFUP

Journal

Title: Antimicrobial Agents and Chemotherapy

Vol. 59

Pages: 5951-5958

ISSN: 0066-4804

Publisher: American Society for Microbiology

Indexing

ISI Web of Knowledge - 19 Citations

Scopus - 33 Citations

Other information

Authenticus ID: P-00G-NR3

DOI: 10.1128/aac.00027-15

Abstract (EN): To gain insights into the diversification trajectories of qnrB genes, a phylogenetic and comparative genomics analysis of these genes and their surrounding genetic sequences was performed. For this purpose, Citrobacter sp. isolates (n = 21) and genome or plasmid sequences (n = 56) available in public databases harboring complete or truncated qnrB genes were analyzed. Citrobacter species identification was performed by phylogenetic analysis of different genotypic markers. The clonal relatedness among isolates, the location of qnrB genes, and the genetic surroundings of qnrB genes were investigated by pulsed-field gel electrophoresis (PFGE), S1-/I-CeuI-PFGE and hybridization, and PCR mapping and sequencing, respectively. Identification of Citrobacter isolates was achieved using leuS and recN gene sequences, and isolates characterized in this study were diverse and harbored chromosomal qnrB genes. Phylogenetic analysis of all known qnrB genes revealed seven main clusters and two branches, with most of them included in two clusters. Specific platforms (comprising pspF and sapA and varying in synteny and/or identity of other genes and intergenic regions) were associated with each one of these qnrB clusters, and the reliable identification of all Citrobacter isolates revealed that each platform evolved in different recognizable (Citrobacter freundii, C. braakii, C. werkmanii, and C. pasteurii) and putatively new species. A high identity was observed between some of the platforms identified in the chromosome of Citrobacter spp. and in different plasmids of Enterobacteriaceae. Our data corroborate Citrobacter as the origin of qnrB and further suggest divergent evolution of closely related qnrB genes/platforms in particular Citrobacter spp., which were delineated using particular genotypic markers.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8