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**11** 

**Usefulness of Pulsed Field Gel Electrophoresis** 

*1Department of Para-Clinical Sciences, The University of the West Indies, St. Augustine* 

A major problem in several health institutions, countries and regions is to categorically define or delineate the source or index case of any microbial organism/s during an outbreak of an infection. Understanding bacterial distribution and their relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. The role of bacterial typing is to determine if epidemiologically identical or related isolates are also genetically related **[Singh A et al, 2006].** Based on phenotypic and genotypic typing methods, multi-drug resistant bacteria organisms such as extended spectrum beta lactamase (ESBL) enzyme producing pathogens e.g. *Escherichia coli* and *Klebsiella pneumoniae* can be traced to have been transferred from one hospital to another, from one country or region to another. Such information and knowledge have greatly assisted clinicians and health care policy makers to determine the best approach of stopping or eliminating such spreads and transfers of the pathogenic organisms involved in

As noted in the reviews by Singh A et al, the use of molecular methods for typing of nosocomial pathogen has assisted in efforts to obtain a more fundamental assessment of strain interrelationship **[Singh A et al, 2006].** Establishing clonality of pathogens can aid in the identication of the source (environmental or personnel) of organisms, distinguish infectious from non infectious strains, and distinguish relapse from reinfection. Many of the species that are key hospital-acquired causes of infection are also common commensal organisms, and therefore it is important to be able to determine whether the isolate recovered from the patient is a pathogenic strain that caused the infection or a commensal contaminant that likely is not the source of the infection. Likewise, it is important to know whether a second infection in a patient is due to reinfection by a strain distinct from that causing the initial infection or whether the infection is likely a relapse of the original infection. If the infection is due to relapse, this may be an indication that the initial

**1. Introduction** 

the infection.

**Assay in the Molecular Epidemiological** 

**Study of Extended Spectrum Beta** 

Patrick Eberechi Akpaka1 and Padman Jayaratne2

*2Department of Pathology & Molecular Medicine* 

**Lactamase Producers** 

*McMaster University, Hamilton, Ontario* 

*1Trinidad & Tobago* 

*2Canada* 

penicillin-binding capacity. *Antimicrobial. Agents and Chemotherapy*, Vol.33, No.11, (November 1989), pp. 1869-1874, ISSN 0066-4804

