Reactive oxygen species and uspA overexpession: an alternative bacterial response toward selection and maintenance of multidrug resistance in clinical isolates of uropathogenic E. coli

AbstractEmergence of multidrug resistance (MDR) in uropathogenicE. coli (UPEC) demands alternative therapeutic interventions. Bactericidal antibiotics at their sub-inhibitory concentration stimulate production of reactive oxygen species (ROS) that results in oxidative stress, generates mutations, and alters transcription of different genes. Sub-inhibitory concentration of antibiotics facilitates selection of highly resistant population. Universal stress protein A (uspA) overexpression in MDR-UPEC at sub-inhibitory bactericidal antibiotics concentration was investigated to explore alternative survival strategy against them. Fifty clinical UPEC isolates were screened. Minimum inhibitory concentration (MIC) against three different bactericidal antibiotics (ciprofloxacin, CIP; ceftazidime, CAZ; gentamycin, GEN) was determined by broth dilution method; ROS production by DCFDA and overexpression ofuspA by real-time PCR were determined at the sub-inhibitory concentration of antibiotics. DNA ladder formation and SEM studies were performed with drug untreated and treated samples. Statistical analysis was done by Student ’st test and Pearson ’s correlation analysis; 25 out of 50 UPEC exhibited high MIC against CIP (>  200 μg/ml), CAZ (>  500 μg/ml), GEN (>  500 μg/ml), with varied ROS production (p ≤ 0.001) in treated than untreated controls. DNA ladder formation confirmed ROS production in drug-treated samples. SEM analysis revealed unaltered cell morpho...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research