Background:
Gram-negative bacteria are increasingly associated with severe infections due to the emergence of antibiotic resistance mechanisms, including Extended-Spectrum Beta-Lactamases (ESBLs) and Metallo-Beta-Lactamases (MBLs). Understanding the prevalence of these enzymes is crucial for effective infection control.
Aim:
To determine the prevalence of ESBL and MBL producing Gram-negative bacteria in clinical samples, investigate their co-expression, and analyze antibiotic susceptibility patterns to inform optimal antimicrobial stewardship and infection control strategies.
Methods:
This observational study was conducted at a rural tertiary care hospital in India, and spanned one year. Clinical samples were cultured and identified. Gram-negative isolates underwent susceptibility testing following CLSI guidelines. Furthermore, Double Disc Synergy Test (DDST) and modified Carbapenem Inactivation Method (mCIM) were utilised for phenotypic detection of ESBL and MBL production, respectively. Subsequently, the data on antibiotic susceptibility and resistance prevalence were analysed.
Results:
Among Gram-negative isolates, ESBLs were detected in 41.8%, while MBLs were found in 23.4%, with 7.4% co-expressing both enzymes. Escherichia coli and Klebsiella pneumoniae were the predominant ESBL and MBL producers. Colistin showed high susceptibility (95.5%). However, significant resistance to levofloxacin was observed. Notably, resistant organisms were isolated from both inpatients and outpatients.
Conclusion:
This study highlights the alarming prevalence of ESBL and MBL producing Gram-negative bacteria, particularly E. coli and Klebsiella spp., in a hospital setting. While colistin showed promising activity, the emergence of resistance in outpatient samples emphasizes the need for stringent infection control measures and judicious antibiotic use.
Key words: Metallo-beta-lactamase, Extended-spectrum beta-lactamase, Gram-negative organism, Antibiotic resistance, Phenotypic detection
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