Prevalence and Molecular Characterization of Aminoglycoside Resistance Genes Among Drug-Resistant Pseudomonas aeruginosa Clinical Isolates in Chinese Hospital.

BACKGROUND

Pseudomonas aeruginosa is a major cause of nosocomial infections, with increasing multidrug resistance complicating treatment outcomes. Aminoglycosides remain a cornerstone for managing P. aeruginosa infections, but resistance is escalating globally. This study investigates the prevalence of aminoglycoside resistance and the molecular basis of resistance, focusing on aminoglycoside-modifying enzyme (AME) and 16S rRNA methylase genes in P. aeruginosa clinical isolates from Anhui, China.

METHODS

A total of 354 non-duplicate P. aeruginosa isolates were collected from three tertiary hospitals between January 2023 and December 2024. Antimicrobial susceptibility was determined using the agar dilution method. Whole-genome sequencing and polymerase chain reaction (PCR) were employed to identify AMEs and 16S rRNA methylase genes. Statistical analyses assessed resistance profiles and gene-phenotype associations.

RESULTS

Aminoglycoside resistance was observed in 63% (222/354) of isolates, with resistance rates highest for streptomycin (60.2%), amikacin (56.1%), kanamycin (55.3%), and tobramycin (45.3%). The most prevalent AME gene was aac(6')-Ib9 (32.3%), followed by aph(3')-IIb (25.5%), aac(6')-IIa (20.8%), and ant(2″)-Ia (11.2%). The 16S rRNA methylase genes rmtB (4.4%) and armA (5.1%) were detected. Resistance genes were often associated with mobile genetic elements, suggesting horizontal gene transfer.

CONCLUSION

The high prevalence of aminoglycoside resistance, driven by diverse AMEs and 16S rRNA methylase genes, highlights the urgent need for enhanced antimicrobial stewardship, molecular surveillance, and infection control measures in Chinese hospitals to mitigate the spread of resistant P. aeruginosa.