Detection of Pathogenicity Island-encoding Virulence Genes of Staphylococcus aureus Isolated from Various Clinical Sources

Document Type : New and original researches in the field of Microbiology.

Authors

1 Mansoura University Hospitals, Mansoura University, Mansoura 35516, Egypt

2 Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt

Abstract

Background: Staphylococcus aureus is an important pathogen that causes a wide range of diseases in humans and animals. S. aureus pathogenicity islands (SaPIs) have a growing family of mobile genetic elements (MGEs) in Staphylococci. MGEs transferred Horizontally play an important part in the evolution of the pathogenic bacteria (S. aureus). Several SaPIs carry staphylococcal enterotoxin and many toxin genes. Objective: The goal of this study is to screen the pathogenicity islands-encoding virulence genes of S. aureus, determine antimicrobial resistance pattern and evaluate the distribution of virulence genes among these isolates. Methodology: A total of 108 S. aureus clinical isolates were identified and antimicrobial sensitivity pattern for twelve antimicrobial agents from different classes was assessed. In addition, Polymerase chain reaction (PCR) was performed for all isolates to detect virulence genes encoding on SaPI. PCR products were purified by The Thermo Scientific GeneJET Gel Extraction Kit. Nucleotide sequencing analysis by using 3500 Genetic Analyzer Version 6.0, (Applied Biosystems™). Using Sanger method, sequences data were assembled by GeneMapper™ secondary analysis software. The data analysis was done by using CLC Sequence Viewer 8 (clc-sequence-viewer.software.informer.com). Alignment of sequences by BLAST search of DNA Data Bank was performed. Identification of ORFs (Open Reading Frame) by using ORF Finder. Results: Out of the 108 S. aureus clinical isolates, 69 isolates (63.88%) were Methicillin-resistance Staphylococcus aureus (MRSA), 24 isolates (22.22%) were Vancomycin-resistance Staphylococcus aureus (VRSA), and 15 isolates (13.88%) were Methicillin-sensitive Staphylococcus aureus (MSSA). Eight hundred sixty-two nucleotides product aligned with groEL gene that encode Chaperonin GroEL protein, and with grol gene that encode Heat shock protein chaperone GroEL. The sequence 708 bp aligned with int gene encodes Integrase, groEL gene, grol gene and ktrB gene (encodes Potassium uptake protein). The sequence 493 bp aligned with hys gene encodes Hyaluronate lyase enzyme and pLys gene encodes Polysaccharide lyase enzyme. The sequence 366bp and 340bp aligned with metQ gene that encode with permease (MetQ/NIpA transporter protein). Conclusion: Identification of Pathogenicity Island (SaPI) virulence genes can provide useful information for understanding the pathogenicity, drug resistance and horizontal genetic transfer that play a vital part within the evolution of S. aureus.

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