The successful in vivo horizontal transfer of mobile genetic elements carrying resistance and virulence determinants have contributed immensely to a global dissemination of virulent and multi-drug resistant pathogens. In addition, the pathogenesis of MRSA infection is enhanced via initial colonization of the skin through the component of the microbial surface antigen recognizing adhesive matrix molecules and by their ability to evade host immune response. Furthermore, it was also observed that the genetic diversity of pathogenic MRSA is due to its’ ability to rapidly acquire resistance and virulence determinants. A characteristic feature that made it one of the most important nosocomial pathogen worldwide. Similarly, the expression of virulence gene in MRSA has been observed to be regulated by the accessory gene regulator system (agr). These system is made up of a series of genes whose product build up quorum-sensing regulatory mechanisms that is growth dependent. In addition, at a certain growth stage, the agr systems triggers a pronounced changes in the expression of genes called the quorum sensing. The findings of this review affirms the importance of horizontal gene transfer in the dissemination of resistance and virulence determinants and as well as the genetic diversity of MRSA.
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading nosocomial
pathogen that is also emerging as a zoonotic pathogen. In this review, it was observed that rapid
emergence of new MRSA clones at a higher frequency has ushered in a new knowledge on the clonality
and epidemic potentials of MRSA. Secondly, the success of treatment and management of MRSA
infection is threatened by the diversity in the clonal types. This is because different clones harbours
different antibiotics resistance characteristics and as such respond differently to treatment. Furthermore,
clonal replacement of hospital-acquired MRSA with community -acquired MRSA has also been
observed. Thirdly, the transmission of MRSA even though previously thought to be exclusively within
the hospital setting through hand contact and nasal colonization has now spread to the community and in
addition human to animal and animal to human transmission has also been observed. Similarly, pet
owners, veterinarians and farmers have been described as high-risked group with potentials of becoming
reservoirs of MRSA. Furthermore, the adoption of hand hygiene in healthcare setting have to a great
extent reduced the incidence of MRSA in the hospital. And lastly, the advent of molecular typing such as
Pulsed Field Gel Electrophoresis (PFGE), Multi Locus Sequence Typing (MLST), Staphylococcal protein
A typing (Spa typing) and Double Locus Sequence Typing (DLST) have proven to be a useful tool in
providing valuable information on the evolution and clonal diversity of MRSA. These in turn help
researchers to answer some pertinent questions on the epidemiology of MRSA.
A novel DNA biosensing platform was designed by the functionalization of iron oxide (Fe3O4)
with the carboxylic group via capping agent, mercaptopropionic acid (MPA) and conjugated
with nanocellulose crystalline (NCC) surface modified with surfactant cetyltrimethylammonium
bromide (CTAB) to assist in the DNA sensing capability. The product of nanocomposites
compound was drop-casted on screen printed carbon electrode (SPCE). Characterization by field
emission scanning electron microscope (FESEM) and energy dispersive X-Ray (EDX)
spectroscopy showing that carboxyl functionalized iron oxide (COOH-Fe3O4) can be hybridized
with NCC-CTA+ via electrostatic interaction.
Despite the continued effort globally made to control the growing case of Tuberculosis (TB), it
continues to be regarded as the second deadliest disease after the HIV. There are various
methods developed to diagnose TB, most of which having the criteria of sensitive, selective,
cheap and portable to be used in robust applications. Even with the advancement in medication,
the important keys including early stage diagnosis is yet to be considered. In diagnosing TB, the
only technique remained as the gold standard method is the culturing method, which is the Acid
Fast Bacilli (AFB) staining. On the other hand, molecular technique utilising Polymerase Chain
Reaction (PCR) assay is preferred as a non-culturing method. Additionally, as molecular
techniques become advanced, real-time PCR or quantitative PCR (qPCR) using multiple probes
in one shot has raised interest among researchers, because it can skip the process of gel
electrophoresis. Recently, researchers have been working on electrochemical DNA sensors
which are sensitive, selective, rapid, cheap and can meet with point of care (POC) testing
requirements to diagnose TB.