Combined Computational and In Vitro Assessment of Azadirachta indica Leaf Extract against Multidrug-Resistant Staphylococcus saprophyticus

Azadirachta indica is widely known for its antimicrobial activity, while Staphylococcus saprophyticus and Citrobacter koseri are notable public health pathogens due to their involvement in skin infections. This study aimed to screen bioactive phytochemicals from the methanolic leaf extract of A. indica and to evaluate their antibacterial potential against these organisms through in vitro experiments and computational analyses. Bacterial strains were isolated from pus samples obtained from human boils. The samples were initially enriched in diluted tryptic soy broth for four hours, then cultured on tryptic soy agar plates and incubated at 37 C for 24 hours. Identification of the bacterial species was carried out by polymerase chain reaction amplification of the 16S rDNA gene following an established protocol. The PCR products were purified using a QIAquick PCR purification kit in accordance with the manufacturer protocol. Sequencing of the purified amplicons was performed by Macrogen Inc., South Korea, using the Sanger sequencing method. The obtained nucleotide sequences were compared with reference sequences using the basic local alignment search tool to verify species identity. Multiple sequence alignment and dendrogram construction were conducted using MEGA software to determine similarity with related organisms. Following confirmation of the isolates, the antibacterial activity of the plant extract and selected antibiotics was examined.