COMPREHENSIVE PHENOTYPIC CHARACTERIZATION AND DRUG RESISTANCE ANALYSIS OF BACTERIAL ISOLATES
Main Article Content
Keywords
Antimicrobial Resistance, Bacterial Isolates, Phenotypic Characterization, IMViC Tests, MacConkey Agar, Multidrug-Resistant Bacteria
Abstract
Antimicrobial resistance (AMR) among clinical bacterial pathogens poses a critical challenge to effective infection management, particularly in resource-limited healthcare settings. Accurate phenotypic characterization combined with antimicrobial susceptibility profiling remains essential for guiding therapy and controlling resistance.
Objectives
This study aimed to perform comprehensive phenotypic identification and antimicrobial resistance analysis of bacterial isolates from urine and pus specimens, with a focus on correlating phenotypic traits to resistance profiles.
Methods
A total of 100 bacterial isolates (50 from urine, 50 from pus) were obtained from routine diagnostic specimens. MacConkey agar was used for preliminary isolation and differentiation of Gram-negative bacteria. Biochemical identification was performed using IMViC tests. Antimicrobial susceptibility testing (AST) was conducted using the Kirby-Bauer disk diffusion method on Mueller-Hinton agar, following CLSI 2023 guidelines. Ten antibiotics commonly used in clinical practice were tested.
Results
Escherichia coli and Klebsiella pneumoniae were the most frequently isolated Gram-negative organisms. Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus demonstrated high levels of multidrug resistance. Meropenem was the most effective antibiotic across isolates, while resistance to cephalosporins and fluoroquinolones was common. Phenotypic identification using MacConkey agar and IMViC testing was consistent with expected profiles and facilitated accurate species differentiation.
Conclusion
The study highlights the prevalence of multidrug-resistant pathogens, particularly among Gram-negative isolates. Continued surveillance, antimicrobial stewardship, and phenotypic diagnostics are vital to manage and contain resistance trends in clinical setting.
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
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J. Suriakumar
Associate Professor, Department of Microbiology, Government Medical College, Dindigul, Tamil
Nadu, India.
T. Murugalakshmi
Assistant Professor, Department of Pharmacology, Government Medical College, Dindigul, Tamil
Nadu, India.
K. Bharathi
Assistant Professor, Institute of Microbiology, Madurai Medical College, Madurai, Tamil
Nadu, India.
