Antimicrobial Resistance and Molecular Characterization of Gene Cassettes from Class 1 Integrons inEscherichia coliStrains

Abstract

To investigate the antimicrobial resistance and molecular characterization of gene cassettes from class 1 integrons in Escherichia coli strains isolated from hospitalized patients. Bacterial identification was conducted using the Vitek-2 Compact system, and antimicrobial susceptibility analysis was performed using the Kirby-Bauer method. Class 1 integrons, integrase genes, the variable regions of integrons and promoters from the isolated E. coli were screened by polymerase chain reaction, and subjected to DNA sequencing. In total, 138 E. coli strains were collected from the hospitalized patients, most from urine specimens (41.30%, 57/138). Antimicrobial resistance to ampicillin (89.86%) was most prevalent, with 79.99% of strains being multidrug-resistant (MDR). The class 1 integron integrase intI1 gene was detected in 67.39% of the isolates (93/138). Three gene cassette arrays and 5 antimicrobial resistance gene cassettes were detected in 69 of the class 1 integron-positive strains. The most common gene cassette array was dfrA17-aadA5 . Of the 93 intI1 -positive strains, 5 different common promoters were detected. The most prevalent common promoter was PcH1, and most isolates contained the dfrA17-aadA5 gene cassette array. In summary, antimicrobial resistance and MDR were prevalent among E. coli isolates in our city Weifang in Shandong Provence China. Gene cassettes of the class 1 integron variable region mostly conferred resistance to traditional antimicrobials. Weak promoters in the variable regions were predominant in this study. Integrons pose a great threat to the treatment of MDR bacterial infections and further investigations are needed.

Genomic characterization of multi drug resistant ESBL-producing Escherichia coli isolates from patients and patient environments in a teaching hospital in Ghana

“…In accordance with other studies, the class 1 integron was present in isolates, together with the CTX-M-15 genes and was found to be associated with genes encoding resistance to aminoglycosides (aadA gene cassettes) and/or trimethoprim (dfrA gene cassettes) [23,24]. Gene cassettes with sulphonamides (sul1) and quaternary ammonium compounds (qacE) genes) were also found on class 1 integrons that were closely associated with the chromium (chrA) resistance gene.…”

Comparison of integron mediated antimicrobial resistance in clinical isolates of Escherichia coli from urinary and bacteremic sources

“… a DrfA17, DfrA5, DfrA12, DfrA7 encode dihydrofolate reductase conferring resistance to trimethoprim; AadA2, AadA5 encode aminoglycoside adenyltransferase conferring resistance to spectinomycin/streptomycin [ 9 , 10 ] …”

Prevalence of Class 1 integron in disease-causing carbapenem-resistantEscherichia coliin a tertiary hospital in Kathmandu, Nepal

“…24 However, majority of the isolates (79.2%) were positive for NDM-1, followed by OXA-23, OXA-48, and VIM within the integron-positive population. The dominance of NDM-1 is not surprising, given that it is the most common carbapenemase gene that is found in E. coli [24][25][26][27] and; NDM-1 is particularly associated with class 1 integrons gene cassette and IncM plasmids which help them to mobilize. 34 So the co-occurrence on NDM-1 with intI1 as well as with other OXA variants is concerning as they can transfer the antibiotic resistant trait by moving between species.…”

“…And, several similar studies done in China reported similar higher antibiotic resistance in integron-positive populations. For instance, in 2022 a study 26 on clinical E. coli isolates revealed a higher resistance to Ampicillin (93%), Ciprofloxacin (80%) and Cotrimoxazole (76%). Likewise, clinical E. coli ST131 have been reported to show higher resistance to Cotrimoxazole (95%), Cefotaxime (68%), Ciprofloxacin (68%), Levofloxacin (68%) within integron-positive population 6 .…”