RSF1010 and a conjugative plasmid contain sulII, one of two known genes for plasmid-borne sulfonamide resistance dihydropteroate synthase

Abstract

This paper describes the second type of sulfonamide resistance gene, sullI, and its surroundings in three plasmids, pGS03B, RSF1010, and pGS05. pGS03B3 is identical to pBP1 (36), a 6.3-kilobase-pair (kb) multicopy plasmid that has a resistance region homologous to that of the IncQ plasmid RSF1010, and carries linked sulfonamide and streptomycin resistance (39). The streptomycin resistance specified by these plasmids is due to an aminoglycoside phosphotransferase APH-(3") (21). Plasmid RSF1010 (8.7 kb) is a broad-host-range plasmid found in many different gramnegative bacteria, including the enterobacteria and Pseudomonas aeruginosa (3,11,16). Many IncQ plasmids have only minor differences in the antibiotic resistance region, and it has been suggested that a single IncQ plasmid has spread efficiently around the world with minor modifications (6, 15). The third plasmid, pGS05, is a 100-kb conjugative plasmid specifying the sulfonamide and streptomycin resis-* Corresponding author. tance found in a clinical isolate of Escherichia coli. The sulfonamide resistance DHPS of pGS05 is of type II (37).The nucleotide sequence of the gene coding for the type II sulfonamide resistance DHPS of RSF1010 and pGS05 was determined and compared with the sequence of the sulI gene. The two types of plasmid-encoded sulfonamide resistance enzymes were also compared with the chromosomal DHPS from a sulfonamide-resistant mutant of Streptococcus pneumoniae (24). The polypeptides expressed by the gramnegative sul genes were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis with the maxicell system. MATERIALS AND METHODSBacterial strains and plasmids. E. coli C600 (F-lac leu supE thi thr tonA) was used as host for vector pBR322 (2), JM83 [ara A(lac-proAB)

Characterization of sulphonamide-resistant Escherichia coli using comparison of sul2 gene sequences and multilocus sequence typing

“…This study confirms, as previously reported on a smaller sample (Radstrom & Swedberg, 1988) that the sul2 gene is highly conserved, with few point mutations, though not identical as was previously concluded (Sorum & L'AbeeLund, 2002). Presence of only two main types of the sul2 gene in both human and animal isolates, irrespective of time and geography, suggests horizontal transfer of the gene.…”

“…Among them, the sul2 gene has previously been reported as the most prevalent one in Escherichia coli from pig and pork, poultry and poultry meat, cow and beef, mutton, human faeces and urinary tract infections (UTIs) (Blahna et al, 2006;Gow et al, 2008;Grape et al, 2003;Hammerum et al, 2006;Kerrn et al, 2002;Sunde & Norstrom, 2006;Trobos et al, 2008). Based on a few partial sequences, this gene seems highly conserved, whether it is carried on small nonconjugative or large conjugative resistance plasmids (Radstrom & Swedberg, 1988;Sorum & L'Abee-Lund, 2002). It has been suggested that horizontal gene transfer plays a much larger role than clonal expansion in the spread of trimethoprim-sulfamethoxazole resistance (Blahna et al, 2006), but there is a need to investigate this further.…”

Sequence Variation of the Hydroxymethyldihydropterin Pyrophosphokinase: Dihydropteroate Synthase Gene in Lines of the Human Malaria Parasite, Plasmodium falciparum, with Differing Resistance to Sulfadoxine

“…Clinical isolates of sulfonamide-resistant bacterial species such as the enterobacteria and Pseudomonas frequently contain a plasmid encoding an alternative H,Pte synthase in the form of either the SulI or SulII gene [45]. We note that, relative to other H,Pte synthase sequences, both SulI and SulII possess a dipeptide insertion (Phe-Leu) at the same position as the mutation (position 581) likely to be critical in the K1 isolate of P. fakiparum (Table 2).…”

Use of antimicrobials in veterinary medicine and mechanisms of resistance

“…Gene sulI is part of class I integrons in transposon Tn21 which is often found on conjugative plasmids. The sulII gene occurs together with a streptomycin resistance gene on conjugative or non-conjugative plasmids [29,49]. A number of different dhfr genes have been described among gram-negative bacteria, several of which are part of gene cassettes [29].…”