Disease relevance of sul1

• Novel complex sul1-type integron in Escherichia coli carrying bla(CTX-M-9) [1].
• In 200 sulfonamide-resistant Portuguese Salmonella isolates, 152 sul1, 74 sul2, and 14 sul3 genes were detected [2].
• The distribution of sulphonamide resistance genes sul1, sul2 and the recently discovered sul3 was studied in a collection of clinical isolates of Enterobacteriaceae [3].
• In this study the presence of the blaCARB-2 (ampicillin), cmlA (chloramphenicol), aadA2 (streptomycin/spectinomycin), sul1 (sulphonamide), and tetG (tetracycline) resistance genes in isolates of one such phage type, U302, have been determined [4].

High impact information on sul1

• Potential silencing of the resistance genes bla(OXA-2), aadA1, sul1, and tetA carried on the plasmid pVE46 in a recent porcine isolate of Escherichia coli was investigated following oral inoculation of the strain into organic piglets [5].
• All strains harbored a qnrA gene located on a sul1-type class 1 integron with similar structure to the In36 integron [6].
• Examination of the other three bla(CTX-M) genes by cloning, sequencing, and PCR analysis revealed the presence of a complex sul1-type integron that includes open reading frame ORF513, which carries the bla gene and the surrounding DNA [7].
• Negative associations were found between resistance genes encoding resistance to the same antimicrobial agent: tet(A)/tet(B), sul1/sul2 and strA-strB/aadA1 [8].
• Transformation experiments confirmed statistical associations by demonstrating that elt, estB, astA, aadA and sul1 were located with catA1 on a large ETEC plasmid [9].

Biological context of sul1

• A sul1-type class 1 integron containing an aacA1-orfG gene cassette was identified upstream of bla(CMY-9) and ended with a truncated 3' conserved segment [10].
• Furthermore, the presence of the common DT104 antibiotic resistance genes for the penta-resistance type ACSSuT, aadA2, floR, pse-1, sul1 and tet(G), was also studied because of the authors' focus on this emerging type [11].
• The origin of sul1 and sul2 found in isolates from healthy humans is speculative, but their spread from pigs to humans via the food chain is possible [12].

Associations of sul1 with chemical compounds

• Transfer of antimicrobial resistance (ampicillin, streptomycin and sulphonamides), the tem-1 gene and markers (int1, qacEDelta1, sul1) characteristic of class 1 integrons were evident in one MDR isolate (resistant to 4 antimicrobial classes) when conjugation and transformation experiments were performed [13].
• Two genes, sul1 and sul2, mediated by transposons and plasmids, and expressing dihydropteroate synthases highly resistant to sulfonamide, have been found [14].
• RESULTS: In 64 sulphonamide-resistant isolates, 39 sul1 genes and 48 sul2 genes were detected [3].
• For each antimicrobial agent, the predominant resistance genes were ampicillin, bla(TEM) (94%); chloramphenicol, catA1 (100%); gentamicin, aac(3)-IV and aac(3)-II (50% each); kanamycin, aphA1 (100%); streptomycin, aadA1- like (66%); sulfamethoxazole, sul1 (59%); tetracycline, tet(A) (86%); and trimethoprim, dfrA1-like (83%) [15].

Other interactions of sul1

• An additional pool of resistance genes included tetA, drfA14 or dfrA17, sul1 or sul2, aac(6')Ib, and aac(3)IIb [16].
• All sulphonamide resistant E. coli isolates were investigated for the presence of sul1, sul2, sul3 and intI1 genes by PCR [12].
• Sequencing of plasmids isolated from the transformants identified sul1, aac(6')-Ib and bla(CTX-M-2) [17].

References