Escherichia coli is a part of human intestinal flora and considered the second most common death factor between children younger than five years. Escherichia coli Shiga-like, Heat-labile toxins and multidrug-resistant are important virulence factors. Therefore, the main targets of this work were molecular diagnosis and characterization of toxine genes Shiga-like and Heat-labile and resistance genes of ciprofloxacin and gentamicin on molecular basis for Escherichia coli isolated from children stool sample in Egypt. The gene detection was carried out using two different approaches which were using chromosome and plasmid. Escherichia coli isolates were resistant to 24 antibiotics including four categories based on their functions. For example, ciprofloxacin, gentamicin, novobiocin and vancomycin. All of tested strains showed band near 300 bp that represents of shiga-like toxin (SLT) gene in their genomic DNA. Heat-labile toxin (LT) fragment ~ 200 bp was detected in plasmid of strain 8H and 8G. Moreover, gentamycin resistance fragment (aac C2) was detected in chromosomal DNA of all strains as a single robust fragment of molecular weight ~ 856 bp. In the case of ciprofloxacin-resistance gene a slight amplification was detected in strain 8G as well as 8H at about 1 kb and 800 bp in genomic, while it was absent in plasmids of tested strains.

The fungal pathogens considered the major human opportunistic, 50–60% of candidiasis cases patients Candida albicans. Green synthesis of AgNPs from NaNO3 using Curcuma extract was performed. UV–Vis spectrophotometry and TEM characterization were measured. AgNPs absorption peak showed between 420-440 nm and results of TEM observed, the AgNPs has a uniform regular coccus shape and size of AgNPs was ranging from 50 to 12nm with average 37nm. The activity of AgNPs as antifungal agent against Candida albicans was determined using agar well diffusion method. AgNPs showed greater antifungal activity with inhibition zone diameter 28mm at 30μg/ml. The antibiofilm activity of AgNPs was assayed in 96-well polystyrene plates and 3 ml polyethylene tube. Obviously, remarkable progressive inhibition of biofilm formation was noticed with increasing of AgNPs concentrations. Determination of AgNPs cytotoxicity on normal lung fibroblast (WI-38) cells using MTT protocol was performed. The viability observed at concentration 31.25 was 44% with IC50 value 30.5μg ml−1. When Curcuma AgNPs are used to local infected wound, may inhibit Candida cells without bad side effect on host cells surrounding the infected wounds.

Staphylococcus aureus is one of the most common and distributed pathogens. S. aureus was resistant to 11 antibiotics including four categories based on their functions. Synthesis of copper nanoparticles (CuNPs) from CuSO 4 .5H 2 O using ascorbic acid was performed. Properties of CuNPs using UV and TEM were measured. Results of characterization observed absorption peak at 592 nm and CuNPs cubic in shape with average size 3.5 nm. The activity of CuNPs as bactericidal agent against S. aureus was determined using agar well diffusion method. CuNPs showed greater antibacterial activity and MIC was 40 μg/ml. The anti-biofilm activity of CuNPs was assayed in 96-well polystyrene plates and 3 ml polyethylene tube. Obviously, remarkable progressive inhibition of biofilm formation was noticed with increasing of CuNPs concentrations. Determination of CuNPs cytotoxicity on WI-38 cells using MTT protocol was performed. The toxicity observed at concentration 62.5 was 23% with IC50 value 134.65 μg ml −1 .