This write up is a proposal and i require contributions from other microbiologist regarding modern methods that could be adopted for the research, I can be contacted at temidayo.elufisan@nacetem.org

1. Molecular characterization of plasmids isolated from resistant strains of Staphylococcus
aureus isolated from different infectious sources.
Microbial resistance is a global menace and had contributed significantly to the cost of treatment,
increased hospital stay and the incidence of untreatable disease conditions (Elufisan et al, 2012).
Various factors had been attributed for the emergence of resistance among bacterial species;
these factors include transfer of resistant gene which may either be borne on chromosome or
plasmid. The most common mechanism of resistant transfer is known as Horizontal gene
transfers which usually through conjugation, transformation or transduction and may involve
other mechanisms such as gene insertion or acquisition of moveable genes also known as
transposon. The role of plasmid in bacteria resistance to antimicrobial have long been identified
such that some group of plasmids are referred to as Resistant plasmid because of their ability to
confer resistance on bacteria species against antimicrobial agent. Plasmids are extrachromosomal
single DNA unit found inside the bacterial cells which are capable of independent replication
within their host. Different plasmids confer resistant on different bacteria species and are often
differentiated based on their molecular size and molecular structure.
In earlier studies isolated plasmid has been molecular characterized and has been employed for
the characterization of different strains of bacteria. Ridley et al., 1998 adopted plasmid analysis
and other molecular techniques such as ribotyping for the genetic characterization of some
strains of Salmonella enteritidis. Similar plasmid analysis was adopted for the epidemiological
studies of food borne diarrheal diseases. The outcome of their finding evidently suggests plasmid
as an able to for epidemiological studies and may also go a long way to be used as a tool in
understanding bacterial route of infection. Adeleke and Elufisan, 2012 suggested that plasmid
curing response observed in staphylococcus aureus isolated from two infectious routes may
suggest its possible implication as a tool for understanding microbial route of infection.
Leveraging on these observation I have chosen to carry out a study on the possibility of using a
typical Bacteria response to plasmid curing couple with molecular characterization of the
observed plasmid for the epidemiological study of Bacterial route of infection.
Staphylococcus has been adopted for this study because of its long history of resistance and also
being the most commonly isolated resistance gram positive bacteria. Staphylococci are gram
positive cocci which usually appear in a grapelike cluster (Harris et al, 2002). Staphylococcus is
a genus which has several species among which are Staphylococcus aureus, Staphylococcus
epidermidis, Staphylococcus saprophyticus, Staphylococcus haemolyticus, Staphylococcus
hominis and many other species. However, the species of interest to this study is Staphylococcus
aureus being the most commonly isolated species from human infections and until recently were
considered as the only staphylococcal pathogen of human. Staphylococcus is often distinguished
from other member of the genus by their ability to produce coagulase, an enzyme which
coagulates the blood plasma. Similarly their tendency to grow in 1% Nacl has been used to
distinguish them from other micrococci which are also firmicutes and member of the order
Bacillale (Totora, Funke and Case, 2013). Resistant Staphylococcus species has been isolated

2. from various infectious sources in which most resistant cases have been associated with the
presence of resistant plasmid. Even though there are been various studies in which plasmid has
been isolated characterized and used to establish microbial cause of infection, no serious research
has been carried out on Staphylococcus aureus in this respect and also there have been no
published work which had tried to use molecular characterization of plasmid and isolated
plasmid size for the identification of the route of infection hence the need for this study.
Aim
This study therefore aims at investigating on the possibility of using plasmid size for the
identification source of staphylococcus isolation. It also aims at comparing the similarity
between plasmid molecular structures and thus use them in the identification of different
Staphylococci strains.
Material and Method
Both rapid technique involve the use of kit and conventional methods will be adopted for the
phenotypic identification and biochemical identification of Staphylococcus aureus
References
A. M. RIDLEY,* E. J. THRELFALL, AND B. ROWE, (1998) Genotypic Characterization of
Salmonella enteritidis Phage Types by Plasmid Analysis, Ribotyping, and Pulsed-Field Gel
Electrophoresis; Journal of clinical microbiology, Aug. 1998, p. 2314–2321
Elufisan, T. O, Oyedara, O. O, and Oyelade B, (2012). Updates on microbial resistance to Drug,
Africa Journal of Microbiology Research
Elufisan and Adeleke, 2012; The Epidemiological role of plasmid in the identification of
Staphylococcus route of infection; Journal of MiddleEast of Science and Technology pg 27-44
Harri, L.G, Foster, S.J, and Richards, R.G (2002). An introduction to staphylococcus aureus, and
techniques for identifying and quantifying S. aureus adhesins in relation to adhesion to
biomaterials: review; G. Harris European Cells and Materials Vol. 4. (pages 39-60)
Tortora G.J., Funke, B.R, and Case, C.,I, 2013. Microbiology an Introduction 11th
edition; edited
by Keyler Volker. Pearson Publication