Microbial antibiotic resistance is rapidly increasing as a result of overuse or misuse of antibiotics, as well as a lack of new, effective antibiotics. Alternative antimicrobial treatments, such as nanoparticles, and their potential for stronger synergetic effect when paired with other active chemicals, could be a viable option. This study is prepared to estimate the antibacterial activity of silver nanoparticles (AgNPs) that have been synthesized using the biomass-free filtrate of Aspergillus flavus. The formation of AgNPs was reported by color changed to a dark brownish-black after 72 hours of incubation. The AgNPs surface plasmon resonance peak was indicated in the UV–Vis spectrum at 427 nm. The synthesis of AgNPs with a nanoparticle size of 10 to 35 nm was validated using transmission electron microscopy. The increase in folding area was calculated to detect the synergistic potential of the combined AgNPs with a broad range of conventional antibiotics. AgNPs have broad-spectrum activity against all strains tested. The most sensitive strain was Escherichia coli (11 mm), whereas the most resistant strain was Pseudomonas aeruginosa, as indicated by the lowest inhibition zone (7 mm). The lowest Minimum Inhibitory Concentration indicated was against K. pneumonia and Enterobacter cloacae (0.025 mg/mL, each), followed by Staphylococcus epidermidis (0.05 mg/mL), E. coli and Shigella sp. (0.075 mg/mL, each), and then S. aureus (0.1 mg/mL). Notable synergy was reported between AgNPs and either ampicillin, erythromycin, ceftriaxone, vancomycin, azlocillin, or amoxicillin against S. aureus in the range between 29.3-fold to 8-fold. In addition, synergy was seen between AgNPs and either vancomycin, clindamycin, or erythromycin against P. aeruginosa (31.1-8.0-fold). Also, a maximum increase in IFA when erythromycin and vancomycin were synergized with AgNPs against E. cloacae was reported (IFA of 10.0 and 9.0, respectively). Similarly, AgNPs with either aztreonam or azlocillin against E. coli and amoxicillin, ciprofloxacin, or ceftriaxone against Shigella sp. caused an increase in the fold area of inhibition of between 5.3-3.7-fold. This result may have an advantage in encouraging the use of combined AgNPS with conventional antibiotics in treating infectious diseases caused by antibiotic-resistant bacteria.

Resistance to antibiotics is a significant public health issue in preventing infectious diseases. This study was designed to evaluate the antibacterial activity of eucalyptol, γ-terpinene, p-cymol and punicalagin against Methicillin (Oxacillin) resistant strains. The synergistic effect of these compounds with cefotaxime against Staphylococcus aureus was investigated. The lowest MIC value observed was 0.08mg/mL for punicalagin against S. aureus, followed by the MIC values of punicalagin against E. aerogenes, E. coli and K. pneumoniae (0.16 - 0.63mg/mL). The activity of p-cymol against S. aureus is ranked second, as indicated by the MIC value (0.63mg/mL). The results of the combination study showed that the maximum Increase in Folding Area (IFA) was reported when punicalagin was combined with cefoxitin, cefotaxime, oxacillin, and piperacillin. An effective IFA was observed when p-cymol was tested with piperacillin, cefixime, cefotaxime, oxacillin, and cefoxitin. Based on the checkerboard assay, the MIC of cefotaxime decreased from 60 to 7.5µg/mL when combined with punicalagin indicating a significant synergistic effect between cefotaxime and punicalagin against S. aureus. In conclusion, punicalagin improved S. aureus susceptibility to cefotaxime, suggesting that using these two medicines together can reverse beta-lactam resistance in methicillin (oxacillin) resistant S. aureus. Further works are required to generalize this result and then it may be useful for treating diseases caused by methicillin (oxacillin) resistant strains.

Probiotics are live microorganisms that can improve the host’s health when given in sufficient doses. Due to growing consumer demand for poultry raised without antibiotics supplementation, the usage of probiotics has been rising gradually over time in poultry. This review aimed to summarize the impacts of probiotics on poultry’s nutrient utilization, growth and carcass parameters, gut morphology, laying performance, biochemical parameters, immunity, and gut microbiota. The results revealed that probiotics enhanced the growth performance via improving digestion of protein, lipids, and carbohydrates, improving feed conversion ratio (FCR), increasing carcass and organs weights, improved liver and kidney function parameters, antioxidant effects, decreased serum lipids and cholesterol, improved poultry immunity via improving gut health and synthesis of antimicrobial peptides and prevention of microbial colonization, improved laying performance, fertility, hatchability and eggshell thickness. Therefore, probiotics have various benefits in poultry production compared to banned antibiotics. However, they are not always guaranteed to be growth promoters due to poorly understood modes of action, including their interaction with the host. So, further studies concerning their impacts on meat quality and histopathological changes are still required.

The aim of this study was to investigate the antibacterial activity of Azadirachta indica leaf extracts against Staphylococcus aureus, Escherichia coli, Streptococcus pneumonia and Proteus mirabilis. This was performed using the disc diffusion method and the microdilution method (MIC). Solvents of variable polarity were used to extract the components of A. indica. The highest yield of extraction was obtained from methanol (3.30%), followed by ethanol (3.00%), ethyl acetate (1.50%) and hexane (0.90%). In general, A. indica leaf extracts exhibited broad spectrum antibacterial activity. The extracts of A. indica were shown to inhibit all tested strains in a dose dependent manner and the maximum activity was reported for the methanol extract followed by ethanol, ethyl acetate and hexane extracts. The most effective extract was methanolic leaf extract against P. mirabilis (inhibition zone equal to 28 mm and MIC equal to 0.47 μg/mL). Hexane extract showed no antibacterial activity against all strains tested. The chemical composition of the most effective extract, methanolic extract, has been analyzed using Liquid Chromatography–Mass Spectrophotometer (LC-MS) and the most dominant components were quercetin (20.4%), linoleic acid (14.5%), β-sitosterol (13.5%), myristic acid (11.3%) and oleic acid (7.3%). In conclusion, the potent antibacterial activity of A. indica is due to the polar compounds. The best solvents to extract the active antibacterial ingredients are solvents with high polarity such as ethanol and methanol.

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