Bacteriological analysis of Extended spectrum beta lactamase Producing gram negative bacilli From clinical samples

Abstract

newline Introduction: newlineDrug Resistant bacteria are emerging world wide and their presence in a clinical infection can result in treatment failure, if the wrong drug are used. ESBL are a group of enzymes that mediate resistance to extended spectrum (3rd generation) cephalosporin and monobactam. and#946;-lactamase are produced by several Gram negative organisms, the most important single mechanisms of resistance to penicillins and cephalosporins. newlineAim and Objectives : newline1. Isolation and identification of Gram negative bacilli from various clinical samples like urine, exudates and respiratory specimens. newline2. To carry out antimicrobial susceptibility test for preliminary identification of extended spectrum beta lactamase producing Gram negative bacilli. newline3. Phenotypic detection of the extended spectrum beta lactamase producers by double disc synergy method. newline4. Phenotypic detection of AmpC producers among ESBL strains newline5. Genotypic detection of ESBL type using appropriate primers by PCR Amplification. newlineMaterials and methods : newlineThis descriptive study was carried out in the department of Microbiology at Chettinad Hospital and Research Institute, Kelambakkam, Chennai. Clinical samples collected from the patients include urine, pus, sputum, throat swab, pleural fluids, endotracheal aspirates, bronchoalveolar lavage, woundswab, central venous catheter tip and all body fluids. The samples were processed for the identification of organisms according to standard procedures. Antimicrobial susceptibility testing of the isolated organisms was done by Kirby Bauer disk diffusion method as per the recommendation of the CLSI guidelines.The ESBL production was tested by the Modified Double Disc Synergy Test (MDDST) by using a disc of Piperacillin/ Tazobactam along with cefotaxime. AmpC detection was carried out according to Jennifer et.al., All the isolates which showed a synergistic effect with cefotaxime only in MDDST were further tested for the AmpC enzyme production by AmpC disc test after an initial screening with a cephoxitin (30