Isolation and identification of Non fermentor GNB and detection of bla VIM mediated carbapenamase resistance from clinical isolates in a Teriatary care Hospital

Suyambu Meenakshi, R P R (2018) Isolation and identification of Non fermentor GNB and detection of bla VIM mediated carbapenamase resistance from clinical isolates in a Teriatary care Hospital. Masters thesis, Tirunelveli Medical College, Tirunelveli.


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INTRODUCTION: Non fermenter Gram negative bacilli were considered as contaminants or commensals of little significance1. However, recent literature review shows that these organisms are now associated with life-threatening infections such as septicemia, pneumonia, urinary tract infection, meningitis, surgical site infection, ventilator associated pneumonia (VAP), wound infection, osteomyelitis etc. They account for around 15% of all bacterial isolates from clinical samples1 Pseudomonas and Acinetobacter species together accounted for 84.06% of NFGNB. Carbapenemases are diverse enzymes that vary in their ability to hydrolyze carbapenems and other beta lactams. Detection of carbapenemase is a crucial infection control issue because they are often associated with extensive antibiotic resistance, treatment failures and infection associated mortality5.. This study focuses on the detection of carbapenemase and metallo-β-lactamase production in clinical isolates of Non Fermentor Gram negative bacilli. AIMS AND OBJECTIVES: 1. To isolate and identify Non fermentor Gram negative bacilli from clinical specimens. 2. To determine the Antibiogram of identified non fermenting gram negative bacilli. 3. To detect the production of carbapenemase by non fermenting gram negative bacilli using phenotypic methods. 4. To detect the presence of metallo betalactamse using bla VIM gene by Real time PCR. MATERIALS AND METHODS: The study was carried out in the department of Microbiology, Tirunelveli Medical College. A total of 100 isolates of Non Fermenter Gram Negative Bacilli were isolated from specimens of respiratory tract infection, wound infection, urinary tract infections, septicaemia, post operative wound infections, ear infections satisfying both inclusion and exclusion criteria. The isolated NFGNB were subjected to meropenem resistance by disc diffusion test and Those strains which show resistance to meropenam will be subjected to Carbapenamase detection method by using, Double disc synergy test , combination disc method and MBL E test. bla VIM gene responsible for metallobeta lactamase production is detected for the resistant isolates by performing Real time PCR. RESULTS: Among the 100 non fermenter isolates, 87 were Pseudomonas aeruginosa and 13 were Acinetobacter baumanii. Maximum number NFGNB were from the male patients(62%) and they were in the age group of 40-50(25%). More number of NFGNB were from Medical ward(41.4%) and the they were maximally isolated from pus(37%). Screening with meropenem disk showed 32% of isolates were positive for carbapenem resistance. Among them CDT detected 59.3%, DDST 50% and E test 46.8% of theMBL producer. MDR NFGNB were 13 and MBL producers were 5 among the 32 isolates. 11 % of the isolates were positive for bla VIM gene by real time PCR. CONCLUSION: The proper identification of NFGNB up to the species level together with monitoring their susceptibility patterns are mandatory for proper management of infections caused by these pathogens. The antibiotic susceptibility patterns may change with time and may vary from hospital to hospital. Metallo-β-lactamases are one of the most worrisome resistance mechanisms because in addition to limiting treatment options, their genes are carried on highly mobile elements, allowing easy dissemination. Rapid detection of MBLs is essential. This could help to modify therapy and to initiate effective infection control to prevent further dissemination.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Non fermenter Gram negative bacilli ; meropenem ; carbapenemase resistance.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 12 Jul 2018 18:52
Last Modified: 12 Jul 2018 18:52

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