Screening and Characterization of Waterborne E. coli from Children with Diarrheal Infections and Evaluation of the Bactericidal Efficacy of Plant Extracts and Nanoparticles Against Pathogenic Isolates.

Bacterial infections including diarrhea are most common among children. Current study involved the screening of pathogenic E. coli from children with diarrheal infections. Stool samples were collected from pediatric departments of public hospitals aseptically using autoclaved swabs containing Cary Blair transporting medium. Six diarrheal stool samples were spread on EMB agar media. All samples showed the presence of E. coli except one sample. Isolated bacterial colonies were streaked on nutrient agar plates for pure culture. Pathogenicity test was done using blood agar medium. Two strains exhibited beta hemolysis. Antibacterial activity of different biological agents such as antibiotics, nanoparticles and plant extract were also studied. Seven antibiotics solutions (Amoxicillin, ceftriaxone, chloramphenicol, ciprofloxacin, oxytetracycline, Doxycycline, Azomax) and one antibiotic disc (Meronem) were applied to check the resistance/sensitivity of bacterial strains against them by well diffusion method and disk diffusion method respectively. The zones of inhibition of these antibiotics or antibiotic susceptibility for all these strains were different. Four silver nanoparticles of Cassia fistula, Eucalyptus, Azadiracta indica, calotropis proceri and four plant extracts (Cassia fistula, Euclyptus, Azadiracta indica, calotropis proceri) were applied against isolated E. coli strains. The zone of inhibition of these nanoparticles and plant extracts for all these strains were different. Strain 2 showed maximum sensitivity against Meronem with 12mm Zone of inhibition while same strain was resistant against chloramphenicol, Doxycycline and oxytetracyclin. Bacterial isolates were resistant against plant extracts but showed susceptibility against nanoparticles. It can be concluded from current study that E. coli is associated with diarrheal infections among children. The prevalence of this infection can be prevented via hygienic conditions and proper treatment using different antibacterial agents.