Characterization of Aminoglycoside-Modifying Enzymes in Uropathogenic Enterobacterales of Community Origin in Casablanca, Morocco

Community-acquired urinary tract infections (UTIs) represent a significant public health issue, primarily due to the increasing antibiotic resistance among uropathogens. This study assesses the resistance status of uropathogenic community Enterobacterales to various antibiotics, particularly aminoglycosides, and determines the prevalence of aminoglycoside-modifying enzyme (AME) genes, while investigating the coexistence of 16S rRNA methylating enzymes. We analyzed 628 clinical isolates of Enterobacterales obtained from 4282 cytobacteriological urine examinations at the Pasteur Institute Casablanca, Morocco, collected from October 2018 to December 2021. Identification and antibiotic susceptibility testing were conducted using the VITEK 2® COMPACT system, following CA-SFM guidelines. DNA extraction utilized the heat shock method, and subsequent PCR was performed. Gram-negative bacteria accounted for 85% of isolates, with Enterobacterales representing 91% of this group. E. coli (73%) and Klebsiella pneumoniae (20%) were the most common species among Enterobacterales. Resistance was particularly high for ampicillin (76.7%) and amoxicillin-clavulanate (58%). Among aminoglycosides, gentamicin and tobramycin resistance rates were 33.5% and 35%, respectively, while amikacin resistance was observed in 21.3% of isolates. High frequencies of AME genes were detected, with AAC(3′)-IIa (27.7%) and AAC(6′)-Ib (25.9%) being the most prevalent. Notably, no 16S rRNA methylation genes (rmtA, rmtB, rmtC, rmtD) were found. All tested strains exhibited biofilm-forming capacity, with K. pneumoniae demonstrating intense biofilm production. The study highlights a concerning trend of antibiotic resistance among uropathogenic Enterobacterales in the community setting, correlating genotype with resistance phenotype and emphasizing the need for enhanced surveillance and targeted treatment strategies.