Characterization of Trimethoprim-Sulfamethoxazole Resistance Genes and Their Relatedness to Class 1 Integron and Insertion Sequence Common Region in Gram-Negative Bacilli

Abstract

Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infections, but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram-negative bacilli. Consecutive nonduplicate TMP-SMX nonsusceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. The minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons, and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMP-SMX. Their MICs were all over 640. In E. coli and K. pneumoniae, sul1 and dfr genes were highly prevalent in relation with integron1. The sul3 gene was detected in E. coli. However, in P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron; however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pneumoniae, and Acinetobacter spp. but the relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in six isolates of E. coli. In conclusion, resistance mechanisms for TMP-SMX were different between Enterobacteriaceae and glucose non-fermenting gram-negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram-negative baciili, so the adoption of prudent use of antimicrobial agents and the establishment of a surveillance system are needed.

Isolation, Antimicrobial Susceptibility Profile and Detection of Sul1, blaTEM, and blaSHV in Amoxicillin-Clavulanate-Resistant Bacteria Isolated From Retail Sausages in Kampar, Malaysia

“…This observation was in agreement with the previous studies, whereby the Sul 1 gene was highly prevalent in relation with integron 1 in P. aeruginosa (18, 42). The dissemination of Sul 1 may be a result of the horizontal transfer of antibiotic resistance gene cassettes (42).…”

“…This observation was in agreement with the previous studies, whereby the Sul 1 gene was highly prevalent in relation with integron 1 in P. aeruginosa (18, 42). The dissemination of Sul 1 may be a result of the horizontal transfer of antibiotic resistance gene cassettes (42). A study in Jordan showed that 53.9% of urinary E. coli isolates were positive for one or more of the Sul genes, and significant resistance was observed towards amoxicillin-clavulanate (9).…”

Antimicrobial‐Resistant E. coli from Surface Waters in Southwest Ontario Dairy Farms

“…Our data showed that 28.6% of all E. coli isolates were resistant to at least one of the tested antimicrobial agents, which is comparable with reported prevalence (14–35%) from surface water used for drinking and recreational purposes (Hamelin et al, 2006; Blaak et al, 2015). However, the prevalence of resistance in the present study was lower than that (55–100%) observed in surface water located near wastewater treatment plants and in urban areas, probably due to enrichment of bacteria in surface water from these latter sources (Webster et al, 2004; Watkinson et al, 2007; Ram et al, 2008; Blaak et al, 2015). We found a low proportion (<1%) of E. coli resistant to GEN, NAL, and CIP similar to that found by Ash et al (2002) and Roe et al (2003), who reported that <1% of E. coli from surface waters were resistant to fluoroquinolones and gentamicin.…”

“…Trimethoprim is commonly used in combination with sulfonamide, and the dfr genes conferring trimethoprim resistance were also previously reported in bacteria from surface waters (Hamelin et al, 2006;Stoll et al, 2012;Gomi et al, 2017). Dissemination of sul and dfr genes in bacteria from surface water is probably the result of their presence on class 1 integrons in Gram-negative bacteria: sul genes in their conserved region and dfr genes as gene cassettes in their variable region (Antunes et al, 2005;Shin et al, 2015). Although dfr genes appeared to not be physically associated with sul1 and integrons in the present study, dfr was detected on different contigs in all isolates harboring class 1 integrons.…”

Whole genome sequencing snapshot of multi-drug resistant Klebsiella pneumoniae strains from hospitals and receiving wastewater treatment plants in Southern Romania

“…Similar to AME genes, trimethoprim-sulfamethoxazole resistance genes dfrA, sul1 and sul2 were also detected more frequently in wastewater samples, suggesting the need for careful surveillance of the aquatic reservoir for the presence of this type of resistance, particularly when taking into account that SXT is considered a low-cost alternative treatment by the Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae (CRACKLE) [55,56] and that in K. pneumoniae, sul1 and dfr are highly prevalent in relation with class 1 integrons [57].…”