Staphylococcus aureus is a gram-positive pathogen that can cause peripheral to serious infections in almost all tissues, especially in immunocompromised people, since the introduction of the first antimicrobial agents, it has evolved into one of six “ESKAPE” pathogens that are responsible for the majority of nosocomial infections and able to escape the biocidal action of antibiotics with high resistant rate and pass it into other bacteria. This evolutionary ability of S. aureus to gain resistance, has made it important to get insight into resistance mechanisms to be able to develop new antimicrobial agents. Lemon is a flowering medicinal plant belongs to the family Rutaceae, which contains different antimicrobial components. Nanotechnology has enabled the use of nanoparticles for the treatment of antimicrobial-resistant bacteria. Gold nanoparticles have been reported for their most desirable properties as compared to any other noble metal-based nanoparticles, Titanium dioxide NPs have also been explored as metallic NPs and have been successfully applied in MRSA therapy. This study aimed to study the inhibitory effects of fresh sour and sweet lemon juices plus gold titanium dioxide nanoparticles against multidrug resistant Staphylococcus aureus. A total of (110) different clinical samples had been collected from hospitals looking for Staphylococcus aureus isolates.

Staphylococcus aureus protein A is considered a vital virulence element determinant of its pathogenicity. Its sequence diversity aids in staphylococcal typing and phylogeny. The present study aimed to study the genotyping method for S. aureus isolates by applying Spa typing (variable number tandem repeat) and their role in the phylogenic study. Twenty S. aureus isolates were achieved from various clinical isolates and subjected for complete identification and diagnosis. Later on, these isolates were subjected to DNA extraction and PCR for amplification and sequencing of SPA gene. Spa genotyping showed that out of 20 isolates and their amplified spa gene, 8 different types among the 18/20 isolates were detected and 2/20 isolates could not be typed, as the most commonly observed Spa were t304 (35%), t491 (15%) followed by t078 and t059 (10%). Finally, depending on the bacterial phylogenetic relationships, S. aureus isolates were categorized into 2 clades. The first one contained 18 isolates and the second one contained 2 isolates. Most Spa types were included in clade A (18 isolates) whereas only 2 isolates were involved in clade B. The isolates in clade A were grouped into 3 different groups established on the dissimilarity in tandem repeats of the Spa gene. Cluster 1 contained t304, t078, t044 Spa types, cluster 2 contained t059, t4870 and t386 Spa types and cluster 3 contained t491 and t091 Spa types. Clade B contained 2 Spa types (unknown). The utility of the present work is the application of repetitive tandem repeats within the spa gene for phylogenetic analysis of Staph aureus clinical isolates.