Salmonella Genomic Island 1 is Broadly Disseminated within Gammaproteobacteriaceae

Abstract

Salmonella genomic island 1 (SGI1) is an integrative mobilisable element that plays an important role in the capture and spread of multiple drug resistance. To date, SGI1 has been found in clinical isolates of Salmonella enterica serovars, Proteus mirabilis, Morganella morganii, Acinetobacter baumannii, Providencia stuartii, Enterobacter spp, and recently in Escherichia coli. SGI1 preferentially targets the 3´-end of trmE, a conserved gene found in the Enterobacteriaceae and among members of the Gammaproteobacteria. It is, therefore, hypothesised that SGI1 and SGI1-related elements (SGI1-REs) may have been acquired by diverse bacterial genera. Here, Bitsliced Genomic Signature Indexes (BIGSI) was used to screen the NCBI Sequence Read Archive (SRA) for putative SGI1-REs in Gammaproteobacteria. Novel SGI-REs were identified in diverse genera including Cronobacter spp, Klebsiella spp, and Vibrio spp and in two additional isolates of Escherichia coli. An extensively drug-resistant human clonal lineage of Klebsiella pneumoniae carrying an SGI1-RE in the United Kingdom and an SGI1-RE that lacks a class 1 integron were also identified. These findings provide insight into the origins of this diverse family of clinically important genomic islands and expand the knowledge of the potential host range of SGI1-REs within the Gammaproteobacteria.

Crucial role ofSalmonellagenomic island 1 master activator in the parasitism of IncC plasmids

“…Salmonella Genomic Island 1 (SGI1) is a 42.4-kb MGI that confers resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT) ( 10 ). Since the initial report of SGI1 in Salmonella enterica serovar Typhimurium DT104 two decades ago, a multitude of SGI1 variants has been described in several species of Gammaproteobacteria , including human pathogens such as Salmonella enterica serovars, Proteus mirabilis , Morganella morganii , Providencia stuartii or Klebsiella pneumoniae ( 11–15 ). SGI1 and its variants share a conserved set of genes (described below) and often bear a class 1 integron with diverse combinations of antibiotic resistance gene cassettes ( 16 ).…”

Crucial Role ofSalmonellaGenomic Island 1 Master Activator in Parasitism of IncC plasmids

“…Salmonella Genomic Island 1 (SGI1) is a 42.4-kb MGI that confers resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT) (10). SGI1 variants, which often bear a class 1 integron with diverse sets of antibiotic resistance gene cassettes, are found integrated at the 3' end of trmE (also known as mnmE or thdF) in the chromosome of several species of Gammaproteobacteriaceae, including human pathogens such as Salmonella enterica serovars, Proteus mirabilis, Morganella morganii, Providencia stuartii or Klebsiella pneumoniae (11)(12)(13)(14)(15). SGI1 and its variants are specifically mobilised in trans by the IncC and the closely related IncA conjugative plasmids (16).…”

Genomic islands targeting dusA in Vibrio species are distantly related to Salmonella Genomic Island 1 and mobilizable by IncC conjugative plasmids

“…trmE encodes the 5-carboxymethylaminomethyluridine-tRNA synthase GTPase subunit. SGI1 variants have been reported in a wide array of Gammaproteobacteria , including Proteus mirabilis (PGI1), Acinetobacter baumannii (AGI1), Morganella , Providencia , Enterobacter , Escherichia coli , Vibrio cholerae (GI-15), and Klebsiella pneumoniae [ 7 , 10 , 11 ]. Most variants carry a class I integron structurally similar to the In104 integron of SGI1.…”