Characterization of Aminoglycoside-Resistant Acinetobacter baumannii in Respiratory Specimens: Phenotypic and Molecular Insights

Abstract

Background: The global rise of antibiotic-resistant bacteria presents a formidable challenge to healthcare systems, with Acinetobacter baumannii standing out as a particularly resilient pathogen in hospital settings. The propensity of this organism to exhibit multidrug resistance complicates treatment protocols and underscores the need for in-depth research into its resistance mechanisms. Objective: The objective of this study was to characterize the allelotypic and molecular features of aminoglycoside-resistant Acinetobacter baumannii isolates from respiratory specimens and to determine their antibiotic susceptibility profiles to inform better clinical decision-making and treatment approaches. Methods: This cross-sectional study was conducted at the different labs of various institute of Lahore. A total of 50 respiratory specimens were cultured on selective media. The isolates underwent phenotypic characterization through colony morphology and biochemical tests. Antimicrobial susceptibility was assessed using the disc diffusion method, and molecular analysis was performed using polymerase chain reaction (PCR) to identify the armA gene associated with aminoglycoside resistance. Statistical analysis was executed using SPSS Version 25. Results: Of the 50 isolates, 54% were from male patients and 46% from female patients. Antibiotic resistance was alarmingly high, with resistance rates of 92% for TZP, 90% for FEP, CAZ, IPM, MEM, 86% for AK, 74% for CN, 54% for TOB, and 48% for DO. The presence of the armA gene was detected in 86% of the isolates, suggesting a link to the high levels of aminoglycoside resistance observed. Conclusion: The study revealed a high prevalence of multidrug-resistant Acinetobacter baumannii in respiratory specimens, with significant resistance to commonly used antibiotics. These findings highlight the necessity for continuous surveillance of antibiotic resistance patterns and call for innovative approaches to antimicrobial therapy.