Background: Combinatorial therapy- “nano antibiotics” is an emerging field in nanoscience. In this present investigation, we attempted to combine the green synthesized noble metal nanoparticle and the antibiotic Streptomycin to form bio-conjugated nanoparticles. The newly synthesized Nano antibiotics acted as the antibiotic carrier, functioned as cargo, and delivered the antibiotic. Methods: Comparative studies between the noble metal nanoparticles were attempted for the first time on the grounds of their antibacterial activity. The antibacterial activity of the three noble metal nanoparticles was assessed against Streptomycin-resistant Bacillus sp.; the results obtained proved that silver nanoparticles were a potent antibacterial agent. Still, no antibacterial activity was exerted by gold, and platinum nanoparticles were for the Streptomycin-resistant strain Bacillus sp. To our surprise, the gold and platinum fabricated/bio-conjugated nanoparticle with the antibiotic showed 100% antibacterial activity, whose antibacterial activity was zero when functioning as a nanoparticle alone. Results: The combinatorial therapy of two different clauses of drugs majorly increased antibacterial activity. It enhanced the antibiotic to overcome the resistance exhibited by the bacterial pathogen, and the possible mechanism is elucidated in the present study. Also, an attempt has been made to assess the nanotoxicity of the nano-bioconjugates on RBC and compare their hemocompatibility. The results obtained in the current investigation demonstrate the enhanced antibacterial activity of the green synthesized nanoparticles conjugated with the streptomycin; their efficacy for combinational therapy against resistance in pathogenic organisms highlights the novelty of the work and the comparative study of three different noble metals nanoparticles (Ag, Au, Pt) from single agro-waste for the first time.

Fire blight, caused by Erwinia amylovora, is a devastating bacterial disease that threatens world-wide production of apples and pears. In Canada and the US, streptomycin and kasugamycin are commonly used for the control of this pathogen. There is an urgent need for development of biocontrol agents (BCAs) that can be easily incorporated into integrated pest management pro-grams with high efficacy against streptomycin sensitive and resistant strains of E. amylovora. In addition, excessive use of antibiotics in agriculture has increased awareness of the possibility of antibiotic resistance gene transfer to human, animal and environmental microbes. To address this issue, a phage-carrier system (PCS) that combines Pantoea agglomerans as an antagonistic bacterial carrier of Erwinia phages as a double-pronged treatment for fire blight have been de-veloped. The low viability of P. agglomerans cells following spray drying challenged the industrial scale production of this PCS. In the present research, a spray drying protocol was developed for P. agglomerans by modifying the growth medium and the bacterial cell formulation using D(+)-trehalose and maltodextrin. The developed protocol is amenable to industrial scale pro-duction of the BCA/PCS. The P. agglomerans viability was greater than 90% after spray drying, had a prolonged shelf life of 4 months at 4 C, and the reconstituted cells showed an approximate 3 log reduction in E. amylovora counts with a green pear disc challenge assay.

Recurrent infections after root canal treatments often involve Enterococcus faecalis, a microorganism closely associated with therapy failures due to its biofilm production, survival in nutrient-deprived conditions, and antibiotic tolerance. Essential oils (EOs), which display anti-inflammatory, antimicrobial, and antibacterial properties, exhibit inhibitory effects on the growth of many microorganisms including E. faecalis. This study assessed the in vitro efficacy of combining antibiotics (Gentamicin 1.5mg/ml, Streptomycin 2.5 mg/ml, Ampicillin 5 mg/ml, and Kanamycin 2.5 mg/ml) with Cinnamon (1.25% to 5%) or Clove (25% to 50%) EOs using disk diffusion tests. Disks were treated with EOs-only, antibiotics-only, or EO-antibiotic combinations, placed on BEA agar plates, incubated for 24 hours, and zones of inhibition were measured against E. faecalis. Results showed robust growth inhibition by cinnamon and clove EOs across all tested concentrations. Furthermore, there were synergistic antimicrobial effects when gentamicin, streptomycin and kanamycin were combined with 2.5% and 50% concentrations of cinnamon and clove EOs, respectively, leading to significant growth inhibition of E. faecalis by 139% to 193% compared to using antibiotics or EOs alone. Clove EO showed positive synergism with three antibiotics (gentamicin, streptomycin, and kanamycin) whereas cinnamon EO showed synergism with two antibiotics (streptomycin and kanamycin). These findings suggest that combining cinnamon and clove EOs with aminoglycoside antibiotics can significantly reduce the expansion of E. faecalis compared to antibiotics alone. Further in vivo studies should determine the safety, efficacy, and treatment duration, with the potential to reduce antibiotic dosages and associated toxicity while preventing recurrent infections.

Antibiotic resistance and accordingly their pollution because of uncontrolled usage has emerged as a serious problem in recent years. Hence, there is an increased demand to develope robust, easy, and sensitive methods for rapid evaluation of antibiotic and their residues. Among different analytical methods, the aptamer-based biosensors (aptasensors) have attracted considerable attention because of good selectivity, specificity, and sensitivity. This review gives an overview about recent developed aptasensors for antibiotic detection. The use of various aptamer assays to determine different groups of antibiotics like β-lactams, Aminoglycosides, Anthracyclines, Chloramphenicol, (Fluoro)Quinolones, Lincosamide, Tetracyclines and Sulfonamides are presented in this paper.