Faculty of Health Sciences
School of Medicine
Department of Medical Microbiology
Selected Highlights from Research Findings
The molecular epidemiology of Pseudomonas aeruginosa isolates carrying the novel carbapenem-hydrolyzing beta-lactamase GES-2 was first described in South Africa in the Pretoria Academic Hospital during an international collaborative study involving the microbiology departments of this University and of Hôpital de Bicêtre, Assistance Publique/ Hôpitaux de Paris, Facultè de Médecine Paris-Sud, Le Kremlin-Bicêtre, France. During this study it was found that this specific antibiotic resistance mechanism tend to occur more in physically debilitated long-term intensive care unit (ICU) patients with a total mortality of 62.5%. Results from this study highlighted the futility of prolonged antibiotic treatment and the absolute importance of good housekeeping in the ICU environment. The specific mechanism of transfer of isolates harbouring the GES-2 beta-lactamase between patients and their environment could not be clearly established during this study. It was found however that these isolates were clonally related, this being an argument against de novo mutations arising randomly in the nosocomial environment. From knowledge gained during the initial characterization of the novel beta-lactamase GES-2 and the gene encoding this enzyme, it was clear that this resistance mechanism did not develop spontaneously in Pseudomonas aeruginosa, but was of Enterobacterial origin. This theory will be tested during additional research specifically targeted to find the natural producers of these genetic structures in Enterobacteriaceae originating from the Pretoria Academic Hospital.
Contact person: Dr GF Weldhagen.
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