Aldujaili et al (2020): Extracellular synthesis of silver nanoparticlesNov 2020 Vol. 23 Issue 18 Annals of Tropical Medicine & Public Health http://doi.org/10.36295/ASRO.2020.231804 Extracellular synthesis of silver nanoparticles by Acinetobacter baumanii and antibacterial characterization Nawfal Hussein Aldujaili 1 , Fatima Hamzaa Alzubaidy 2 , and Ali Abdul Hussein 3 1, 2 Department of biology, faculty of science, Kufa University, Iraq 3 Dep.of Analytical Tech., faculty of Medical and Healthy tech., university of Alkafeel, Iraq. *Corresponding author: nawfal.aldujaili@uokufa.edu.iq(Aldujaili) Summary Bioproduction approaches of nanoparticles get a very important field with eco-friendly and economic welfares over physical & chemical methods of production. The purpose is the biosynthesis of AgNPs from non- pathogenic bacterial isolate. Acinetobacter baumanii. Identification to species-level was determined by Polymerase Chain reaction (PCR) with universal primers, the 16S rRNA gene was subjected to nucleotide sequencing. AgNPs were biosynthesized by adding silver nitrate (AgNO3) into the supernatant of A. baumanii at 10 mM. AgNO3 was used as a precursor for the synthesis of AgNPs. Biological AgNPs were originally shown by change the color, yellow to reddish-brown. The categorization of AgNPs accomplished by SEM, XRD, and AFM. SEM exhibited well-dispersed AgNPs, homogenous with a diameter of 18-30nm, with inconstant shapes mostly spherical form. XRD detected the size of AgNPs was 21 nm and the AFM showed the three-dimensional structure of AgNPs and the diameter was 99.82 nm. AgNPs displayed antibacterial action to MDR of E.aerogens, S.aureus, E.coli, S.typhi, K. Pneumonia, P.auroginosa, P.mirabilis, P.Agglomerans, and S.pyogenes. Keywords: Biogenic silver nanoparticles, A. baumanii, Antimicrobial Activity, biosynthesis How to cite this article: Aldujaili NH, Alzubaidy FH, Abdul Hussein A (2020): Extracellular synthesis of silver nanoparticles by Acinetobacter baumanii, Ann Trop Med & Public Health; 23(S18): SP231804. DOI: http://doi.org/10.36295/ASRO.2020.231804 Introduction Nanobiotechnology is a novel ground of synthesis and application of nanoparticles with 1-100nm in size [1, 2] . Nanoparticle formulas of metals as Pt, Ag, and Cu & Au had inhibition against pathogens. AgNPs had likely presentations in Nanomedicine and have been permitted for bactericidal actions against infections and avoidance biofilm creation as well as their sole chemical, electronics and optics [3, 4] . Nanoparticles had exclusive features including antibacterial possessions, magnetic, electronic, optical possessions & catalytic actions [1, 5] . Chemical & physical techniques were established for the making of AgNPs. The green creation is an eco-friendly and cheap bio creation technique for AgNPs. The bio creation way of manufacture is proficient with bacteria, fungi or plant sources. Bacterial metabolites certify speedy & dependable reduction of Ag ions to element. The microbial extract has occasioned in production nanomaterials with specific shapes, size & morphology [6, 7] . The extracellular creation of AgNPs using A. baumannii species seems to be cheap and eco-friendly [8, 9, 10] to improve real antimicrobial mediators that overwhelmed the MDR of microbes [11] . The study is aimed at synthesing AgNPs with A. baumannii and tests antimicrobial activity. Methods Culture of A. baumannii The A. baumannii was obtained from a higher student laboratory in the faculty of science. BHI was inoculated with A. baumannii, incubated at 37°C, 24 hrs, and aerobic condition. A. baumannii was identified based on biochemical and morphological tests [12] . The second activation was worked from the first activation and incubated aerobically at 37°C for 24 hrs [9] . Preparation of cell free supernatant of A. baumannii After 24 hrs, the culture was subjected to 6000 rpm, 25 minutes to make supernatant from A. baumannii. After centrifugation, the cells were precipitated at the lowest of the tube were rejected and supernatants were composed for use in AgNPs biosynthesis [9] .