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Title Antibiotics Were More Effective Against Resistant Bacteria when Combined with Biologically Synthesized Silver Nanoparticles
Clinical Question In patients with resistant microbial infections, can silver nanoparticles be combined with antibiotics to improve the efficacy of antibacterial activity?
Clinical Bottom Line In vitro studies demonstrate greater inhibition of drug resistant bacteria when antibiotics and silver nanoparticles (AgNPs) are conjugated. This is supported by results showing that biosynthesizing AgNPs with antibiotics were more effective against bacteria and at lower doses of antibiotic than when observing the effect of antibiotics alone. AgNP nanomedicine may offer an effective alternative strategy for managing infections.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 23986635Naqvi/20138 multi-drug resistant bacteria strains/5 antibioticsLaboratory study
Key resultsNaqvi et al. concluded, “nanoparticle-antibiotic conjugates lower the amount of both agents in the dosage, which reduces noxiousness and increases anti-microbial properties.” Multidrug-resistant bacterial species were exposed to conventional antibiotics individually and exposed to combined AgNPs and antibiotic. The Kirby-Bauer disk-diffusion method was used to observe a mean 2.8 fold-increased area zone of inhibition with synergistic antibiotics and AgNPs. The proposed mechanism of action involves an AgNP focal core conjugated with the antibiotic, which permits more concentrated antimicrobial/bactericidal action.
#2) 19447203Fayaz/20104 total gram(-) and gram(+) bacteria/4 antibioticsLaboratory study
Key resultsFayaz et al. concluded, “the combination of antibiotics with AgNPs [silver nanoparticles] have better antimicrobial effects.” The study found that the greatest percentage of fold increase for antibacterial activity against gram(+) and gram(-) bacteria was when AgNPs were combined with ampicillin. This was followed in efficacy by kanamycin, erythromycin, and chloramphenicol. The proposed mechanism for ampicillin/AgNP synergistic effectiveness is ampicillin’s action of cell wall lysis followed by penetration of AgNP into the bacterium, preventing DNA unwinding and increasing damage to bacterial cells.
Evidence Search ("nanomedicine"[MeSH Terms] OR "nanomedicine"[All Fields]) AND ((("metabolism"[MeSH Terms] OR "metabolism"[All Fields] OR "synthesis"[All Fields]) AND (("anti-bacterial agents"[Pharmacological Action] OR "anti-bacterial agents"[MeSH Terms] OR ("anti-bacterial"[All Fields] AND "agents"[All Fields]) OR "anti-bacterial agents"[All Fields] OR "antibiotic"[All Fields]) AND (("silver"[MeSH Terms] OR "silver"[All Fields]) AND ("nanoparticles"[MeSH Terms] OR "nanoparticles"[All Fields] OR "nanoparticle"[All Fields])))) AND (("microbiology"[Subheading] OR "microbiology"[All Fields] OR "bacteria"[All Fields] OR "bacteria"[MeSH Terms]) AND resistance[All Fields]))
Comments on
The Evidence
Validity: No systematic reviews or meta-analysis were found on this topic in nanomedicine. No clinical trials have been published to date. The evidence level is low, yet there is consensus amongst the available in vitro studies that the synergistic activity of AgNPs enhances the inhibitory effect of antibiotics on drug resistant bacteria. There is a need for standards and guidelines in the creation of conjugated AgNP/antibiotic regimens. Perspective: More information is needed regarding the mechanism involved in synergistic antimicrobial effects.
Applicability The in vitro studies agree that it is essential to find alternative modalities for addressing the increasing healthcare costs associated with treatment of antibiotic resistant infections. Studies claim that synthesis of biogenic silver nanoparticles may represent advancement in the development of green chemistry with cost savings, as it makes use of microorganisms to create stable metallic nanoparticles.
Specialty/Discipline (Oral Medicine/Pathology/Radiology) (Endodontics) (General Dentistry) (Periodontics) (Prosthodontics) (Restorative Dentistry) (Basic Science)
Keywords AgNP, Nanoparticles, Multi-resistant organisms, Synergistic activity, Antibacterial agents
ID# 2793
Date of submission: 12/01/2014spacer
E-mail drewh@livemail.uthscsa.edu
Author Hannah C. Drew, DDS
Co-author(s) e-mail
Faculty mentor/Co-author Stephan J. Haney, DDS
Faculty mentor/Co-author e-mail haneys2@uthscsa.edu
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