The Epidemiological role of Plasmid Curing in the Identification of Staphylococcus aureus route of Infection

Twenty isolates of Staphylococcus aureus from wound and High vaginal swab extract were cured of plasmid in order to examine the curing response pattern of these bacteria. The aim is to investigate how the pattern of bacteria response to curing can be used to explain the route of microbial infection or pathogenesis. These isolates were selected from a larger population of bacteria isolates which were screened for their susceptibility pattern to commonly used antibiotics. Resistant species were then screened using iodometric technique for the identification of factors responsible for the identified resistance cases in these organisms. The outcome of this test showed that resistance was due to the presence of beta-lactamases a particular resistant gene in bacteria, which could be chromosomal borne or plasmid mediated. The genetic basis of resistance was identified by carrying out a plasmid curing test. The outcome of the test showed that all the bacteria isolate but one have the basis of resistance to be borne on the plasmid located inside their chromosome. This result was then used to investigate the curing response pattern of the twenty selected strains. Only 50% of the isolates were recovered after curing with a mutagen (sodium dodecyl sulphide) and 60% of which were strains isolated from wound while the 40% were those from High vagina swab.