title: Synthesis and characterization of the antibacterial potential of ZnO nanoparticles against extended-spectrum β-lactamases-producing Escherichia coli and Klebsiella pneumoniae isolated from a tertiary care hospital of North India.
abstract: The reemergence of infectious diseases and the continuous development of multidrug resistance among a variety of disease-causing bacteria in clinical setting pose a serious threat to public health worldwide. Extended-spectrum β-lactamases (ESBLs) that mediate resistance to third-generation cephalosporin are now observed all over the world in all species of Enterobacteriaceae, especially Escherichia coli and Klebsiella pneumoniae. In this work, ZnO nanoparticles (NPs) were synthesized by the sol-gel method and characterized by powder X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The image of synthesized ZnO NPs appeared spherical in SEM with a diameter of ≈19 nm and as hexagonal crystal in AFM. Clinical isolates were assessed for ESBL production and shown to be sensitive to ZnO NPs by different methods such as minimal inhibitory concentration (MIC) and minimal bactericidal concentration, time-dependent growth inhibition assay, well diffusion agar methods and estimation of colony forming units (CFU) of bacteria. The lowest MIC value for E. coli and K. pneumoniae was found to be 500 μg/ml. The results showed that ZnO NPs at 1,000 μg/ml completely inhibit the bacterial growth. The antibacterial effect of ZnO nanoparticles was gradual, but time- and concentration-dependent. The maximum inhibition zone at100 μg/ml for E. coli and K. pneumoniae was 22 and 20 mm, respectively. With the increasing ZnO NP loading, there is significant reduction in the numbers of CFU. At the concentration of 1,000 μg/ml, the decline in per cent survival of E. coli and K. pneumoniae was found to be 99.3% and 98.6%, respectively.
authors.affiliation: Department of Microbiology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India. azammicro@gmail.com
authors.forename: Mohammad Azam
authors.initials: MA
authors.lastname: Ansari
authors.forename: Haris M
authors.initials: HM
authors.lastname: Khan
authors.forename: Aijaz A
authors.initials: AA
authors.lastname: Khan
authors.forename: Asfia
authors.initials: A
authors.lastname: Sultan
authors.forename: Ameer
authors.initials: A
authors.lastname: Azam
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D006761:Hospitals; D007194:India; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification; D053768:Metal Nanoparticles; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000494:pharmacology*; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; D015034:Zinc Oxide