The First Saudi Study Investigating the Plasmid-borne Aminoglycoside and Sulfonamide Resistance among Clinical Isolates Genotyped by RAPD-PCR: the Declaration of a Novel Allelic Variant Called and Three Novel Mutations in the Gene in the Plasmid (s).

Background: () is one of the most important nosocomial pathogens responsible for a wide range of infections.

Aim: This study aimed to investigate the existence of the plasmidic genes encoding for aminoglycoside modifying enzymes (AMEs), 16S rRNA methyltransferases (RMT), and the altered dihydropetroate synthase (DHPS) encoded by the gene among clinical isolates collected from Taif, Kingdom of Saudi Arabia (KSA). The mutations in  and genes were also investigated.

Methods: Forty clinical isolates were investigated for their susceptibility to ten antibiotics. The plasmid DNA was extracted and screened for nine genes encoding for aminoglycoside resistance in addition to the gene. The clonal relatedness was determined by random amplified polymorphic DNA (RAPD)-PCR. Mutation in and the genes were detected by capillary electrophoresis sequencing (CES).

Results: All isolates were in which 42.5% of them exhibited a high level of aminoglycoside resistance (HLAR). The most prevalent AMEs and RMT encoding genes were , the two gene variants [ and ], and in which 90%, 87.5%, 85%, and 45% of isolates tested positive, respectively. The other investigated aminoglycoside resistant encoding genes, namely , and rmtB, were not detected. Only 15% of isolates harbored the gene. RAPD-PCR classified the 40 isolates into three clusters in which cluster II was the main cluster. DNA sequencing revealed that 34.29% (12/35) of isolates tested positive for were found to harbor a common missense mutation in position 102 indicating a novel allelic variant named . Also, DNA sequencing revealed three missense mutations in the gene.

Conclusion: This is the first Saudi study to investigate the plasmid borne aminoglycoside and sulfonamide resistance genes among clinical isolates. A novel allelic variant for was detected in addition to novel mutations in the gene.