A Study on Detection and Characterisation of Metallo Beta Lactamase Producing Pseudomonas Aeruginosa.

Divya, B (2013) A Study on Detection and Characterisation of Metallo Beta Lactamase Producing Pseudomonas Aeruginosa. Masters thesis, Madurai Medical College, Madurai.


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INTRODUCTION : Pseudomonas aeruginosa has become one of the most dreadful causes of nosocomial bacterial infections especially in the lung, blood and urinary tract. As a result of its considerable potential to become resistant to many antibiotics, more multidrug resistant strains are encountered as clinical isolates, leaving physicians with a decreasing armamentarium of effective drugs for treatment. Before the advent of modern medical microbiology, there was evidence that P.aeruginosa was a cause of serious wound and surgical infections, as elaborated by Doggett .In 1850, it was noted by Sedillot that there were sometimes blue green discharges on surgical dressings that were associated with infection. In 1862, Luke noted rod-shaped microscopic entities within the blue green pus. In 1882, Gessard isolated the organisms and originally designated them as bacillus pyocyaneus, and other early Microbiologists also isolated the organism from infected sites. Osler in 1925, thought that the organism to be more of a secondary opportunistic invader of damaged tissues as opposed to a primary cause of infection in healthy tissues. P. aeruginosa has emerged as a major human pathogen in the 1960’s, since it can cause infection in immunosuppressed and burns patients as well as cystic fibrosis patients, all of whom were surviving much longer with advanced medical treatments. AIMS AND OBJECTIVES : 1. To study the prevalence of MBL production in Pseudomonas aeruginosa isolates from patients admitted to various clinical departments in Govt.Rajaji Hospital, Madurai. 2. To Identify and confirm MBL production in Pseudomonas aeruginosa isolates by phenotypic and genotypic methods. 3. To compare various phenotypic methods in the detection of MBL with genotypic method(PCR) and to evaluate a simple, cost effective and sensitive method to detect MBL production at the earliest that can be recommended for routine screening of MBL in Microbiological laboratories & thereby reduce the transmission of resistant strains in the community. MATERIALS AND METHODS : It is a prospective study conducted in patients admitted to Government Rajaji Hospital, attached to Madurai Medical College, Madurai. The study was conducted between June 2011 & May 2012. Ethical committee clearance has been obtained from the institution and written informed consent received from the patients before collecting the specimens. A total of 580 clinical samples were collected including pus, sputum, urine, blood, ascitic fluid, endotracheal fluid, broncho-alveolar lavage and wound swab from the patients who were admitted to various clinical departments of Govt. Rajaji Hospital, Madurai. Inclusion Criteria: • Males and females of all age groups were included, • Patients affected with burn wounds, Patients with non-healing ulcer, • Diabetic patients with ulcers, • Patients with provisional diagnosis of Septicaemia and Pneumonia, • Patients with indwelling urinary catheter, • Patients on ventilatory support for prolonged period in IRCU, • Patients with peritonitis. RESULTS : A total of 580 clinical samples of pus, sputum, urine, blood, ascitic fluid, endotracheal fluid, broncho-alveolar lavage and wound swab collected from the patients admitted to various clinical departments of Govt. Rajaji Hospital Madurai were processed and the results. Out of the 580 clinical samples, 175 samples were pus, 114 samples were wound swab, 121 samples were urine, 60 samples were sputum, 88 samples were blood and 22 samples were body fluids.70 samples showed no growth and 510 showed growth. Among the 510 isolates, 108 were Pseudomonas aeruginosa, 202were Gram negative bacilli other than Pseudomonas, 200 were Gram positive cocci. The analysis of specimen wise, age wise and sex wise distribution of Pseudomonas aeruginosa was done. CONCLUSION : The emergence of Gram negative bacterial species with acquired resistance to various broad spectrum Beta lactam antibiotics has become a clinical problem worldwide and particularly Pseudomonas is notorious for causing a wide range of hospital acquired infections. In this study, Carbapenem sensitive MetalloBetaLactamases in Pseudomonas aeruginosa have been found emerging predominantly from burns ward in Govt. Rajaji hospital, Madurai with a prevalence of 16.66% with a predilection to affect males of the middle age group (31- 40 years). Early detection of these strains is crucial to establish an appropriate antimicrobial therapy and to prevent interhospital and intrahospital dissemination and thereby reduce the mortality and morbidity associated with these infections. On comparison of various phenotypic methods, Combined Disc Diffusion Test using Ceftazidime and EDTA was found to be the simple, cost effective and highly sensitive method close to PCR to detect all the carbapenem susceptible MBLs with hidden MBL genes which are a serious threat to infection control efforts. Formulating antibiotic policy, judicial use of higher antibiotics, isolation of MBL infected patients, strict safety precautions such as use of gloves, masks gowns and proper hand washing techniques are the measures that can be taken to combat the serious therapeutic challenge faced with MBL producing isolates. With only a fewer drugs available in the pipeline like Polymyxin B, Colistin (Polymyxin E), Rifampicin and Tigecycline, the judicious selection of antibiotics to treat MBL producing isolates should be implemented.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Detection ; Characterisation ; Metallo Beta Lactamase ; Pseudomonas Aeruginosa.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 14 Aug 2017 17:28
Last Modified: 14 Aug 2017 17:34
URI: http://repository-tnmgrmu.ac.in/id/eprint/1465

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