Single-nucleotide polymorphisms related to fluoroquinolone and aminoglycoside resistance in Mycobacterium avium isolates.

ABSTRACT: Objective:The relationships between fluoroquinolone and aminoglycoside resistance and single-nucleotide polymorphisms (SNPs) in gyrA, gyrB, and rpsL genes were investigated in 95 clinical isolates of Mycobacterium avium from China. Methods:Fluoroquinolone and aminoglycoside resistance were determined by the broth microdilution method. GyrA, gyrB, and rpsL were sequenced, SNPs were identified, and the corresponding amino acid mutations were recorded. Results:The M. avium isolates displayed high levels of ofloxacin (93.68%), ciprofloxacin (92.63%), and streptomycin (65.26%) resistance. Moxifloxacin (18.95%) and amikacin (2.11%) were highly active against the strains. Fluoroquinolone resistance involving gyrA and gyrB gene mutations was identified. For gyrA, the most frequent SNPs were T?C (71/95, 74.74%), followed by A?G (64/95, 67.37%) and T?C (62/95, 65.26%). The amino acid mutations occurred mainly at Gly2444Asp (GGT?GAT) (20/95, 21.05%), Ala2445Ser (GCC?TCC) (20/95, 21.05%), Ala2447Val (GCC?GTC) (20/95, 21.05%), Val2449Ile (GTC?ATC) (20/95, 21.05%), and Glu2450Gln (GAA?CAA) (20/95, 21.05%). Prominent SNPs in gyrB included A?C (69/95, 72.63%), C?T (51/95, 53.68%), and T?G (29/95, 30.53%), and their amino acid substitutions were Ile2160Val (ATT?GTT) (21/95, 22.11%), Ile2160Met (ATT?ATG) (20/95, 21.05%), and Ile2273Leu (ATC?CTC) (11/95, 11.58%). Among the strains with aminoglycoside resistance, SNPs in rpsL were identified mostly at position G?A (73/95, 76.84%). G?C (21/95, 22.11%) was commonly seen. The amino acid mutations primarily involved Ala1539985Thr (GCC?ACC) (19/95, 20.00%), His1539992Asp (CAC?GAC) (19/95, 20.00%), and Gln-1539983Glu (CAG?GAG) (18/95, 18.95%). Conclusion:Our study provides valuable information that could be used for the future diagnosis and treatment of M. avium disease.

SUBMITTER: Pang H 

PROVIDER: S-EPMC5898888 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature