Syed Haroon Hussain, Sukesh Kumar B. Y, Kondal Rao
BACKGROUND: The introduction of Carbapenems (Meropenem, Imipenem) into clinical practice represented a major advance in the treatment of serious bacterial infections caused by beta-lactam resistant bacteria. However, carbapenem resistance has been frequently observed in non-fermenting bacilli like Pseudomonas aeruginosaand Acinetobacter species, probably due to lack of drug penetration and/or carbapenem-hydrolyzing β-lactamases. OBJECTIVES: The objectives of the present study are to isolate nonfermenters from various clinical samples, determine their antibiogram and to detect any carbapenem resistance by the application of routine phenotypic methods. MATERIALS AND METHODS: A total of 132 samples were collected from 132 patients samples includes pus, urine, sputum, blood, endotrcheal tubes, intravenous cannula isolated non-fermenters from various clinical samples and identifying the organism their antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method. Metallo-β-lactamase (MBL) detection was done by the Imipenem-EDTA Combined Disc Method and the Imipenem-EDTA Double Disc Synergy Method. RESULTS: Among 132 isolates, Pseudomonas aeruginosa constituted 115 of the total isolates, Imipenem resistance in the present study in Ps. aeruginosa was 41.73%. Among the 57 isolates resistant to imipenem, 50(87.71%) showed a ≥7mm zone enhancement by Imipenem-EDTA Combined Disc Method, 35 (61.4%) showed zone enhancement by the Imipenem-EDTA Double Disc Synergy Method. CONCLUSION: Among the two tests used in the present study, the Imipenem-EDTA Combined Disc Method was found to be more sensitive (p<0.05). MBL E test can be used to increase the sensitivity of detection
