Correlation between antibiotic resistance and phylogenetic types among multidrug-resistant Escherichia coli isolated from urinary tract infections

Objective(s): Emergence of multidrug resistance has reduced the choice of antimicrobial regimens for UTIs. To understand the association of phenotype and genotype among uropathogens.Materials and Methods: Six hundred and twenty-eight (۶۲۸) urine samples were collected and analyzed. Antibiotic sensitivity pattern was determined by the Kirby-Bauer Disc Diffusion Method and minimum inhibitory concentration (MIC) was tested by the E test. Fluoroquinolone resistant mutations in QRDR of gyrA and ParC, phylogenetic groups, and PAIusp subtype were detected by PCR.Results: Most prevalent uropathogens were Escherichia coli (۵۳.۲%) followed by Klebsiella pneumoniae (۲۱%). Multidrug- resistance was observed in > ۵۰% cases for third-generation cephalosporins and ciprofloxacin and lowest in meropenem. E. coli (۶۶.۲%) and K. pneumonia (۶۴.۴%) were extended-spectrum β-lactamases (ESBLs) producers. MIC to trimethoprim-sulfamethoxazole was highest in E. coli (>۱۰۲۴ µg/ml). In ۸۰ (۲۴%) of the ۳۳۴ E. coli isolates analyzed in detail, ۵۴ fluoroquinolones (FQ) resistant isolates carried mutations (S۸۳L, D۸۷N, S۸۰I, E۸۴V) in QRDR of gyrA and ParC. Out of ۵۴ FQ-resistant isolates, ۴۳ (۷۹.۶%) isolates belonged to the phylogenetic group B۲, and ۱۱(۲۰.۴%) belonged to group D. Isolates belonged to group B۲, ۳۸ (۸۸.۴%) of the ۴۳ isolates carried PAIusp subtype IIa and high frequency of mutation E۸۴V in ParC was detected in ۳۷ (۹۷.۴%). Other mutations, such as S۸۰I, S۸۳L in gyrA and D۸۷N in ParC were found in all resistant isolates.Conclusion: Correlations between phenotype and genotype provided a basis to understand the resistance development in uropathogens, and PAIusp subtyping indicated that E. coli belonged to the B۲ group.

Keywords:

Escherichia coli , ESBL , MDR , PCR , UTI