For close to a decade and a half, the prevalence of MRSA, acronymic to methicillin Resistant Staphylococcus aureus has drastically been on the increase globally. Evidently, severe infections due to MRSA, including bacteremia, are key causes of mortality when compared to a single methicillin-predisposal infection of Staphylococcus aureus. In this regard, extensive researches (name) indicate that, brisk identification as well as antimicrobial vulnerability testing presents a huge impact on the eventual clinical outcome especially on severe infections. The well established testing is on the speedy detection of MRSA when utilizing PCR on the coding of the mecA gene. This is in line with testing for methicillin resistance by use of penicillin binding proteins. The protein here is PBP2a. In addition, this form of PCR was later utilized as a gold standard when detecting methicillin resistance. This is owing to the fact that, methicillin alias oxacillin resistance is quite heterogeneous; and often expressed in vitro.
In the course of the mid 1990s, most of the MRSA isolates were found to be of a phenotype that is very multi-resistant. In this regard, demonstration of the mecA marker was basically taken as an ample determinant of the glycopeptides to be a therapeutic alternative. However, the incumbent testing have revealed that there is an increase prevalence of the recently emerging epidemic strains. Besides, these have reduced resistance pattern especially across Europe. At the same time, outbreaks that consisted of old epidemic strains demonstrated that, resistance to quinupristin-dalfopristin had been acquired. Besides, there is s reduction in its susceptibility towards glycopeptides among the old strains. Other tests indicate that, there are quite intermittent observations in most cases of the linezolid resistance among the Staphylococcus aureus. This further indicates the possibility of a transferable glycopeptides resistance coded as vanA. In this regard, it is evident that, detecting genes that bestow resistance to the old antibiotics is gaining extensive relevance clinically. For instance, macrolides and lincosamidines as well as gentamicin are expansively being used for clinical purposes.
These introductory reviews present the need of carrying out an extensive diagnostic test on the MRSA. This should encompass both tests on the older standard antibiotics along with the novel introduced compounds underpinning its resistance.
P CR Methodology
Multiple methods can be adopted when carrying out PCR tests. This study focuses on multiplex PCR techniques with basis on the demonstration of the most recurrent resistance genes afar mecA. This is fundamental for the assorted groups of antibiotics. In order to successfully carry out this exercise, it is imperative to first effectively perform DNA isolation. In this study, the method described is PCR based and underpins isolation of a genomic DNA whereby it flanks a known sequence of DNA.
In principle, the basis of this method is a directional cloning amid the genomic DNA. Subsequently, this form of directional cloning is adopted into a multiple site (cloning-site) based on a PUC plasmid as a way of generating diminutive genomic library. In this method, the generated library is consequently plated onto various but discerning LA plates that are then incubated overnight. At the same, the recombinant plasmid DNA is simultaneously isolated from the colonies that are resistant, and typically pooled from each of the plates. In subsequent stages, amplification of the PCR is done. This form of amplification principally targets the aforementioned collective recombinant plasmid DNA. This is mostly effective when primers are used that are specifically designed for the PUC vector as well as the known genomic sequence. The combination of an efficient and effective directional cloning as well as bacterial transformation offers somewhat a relative enrichment that suits the genomic sequence that is being studied. At the same time, this generates a simple template of DNA that will enhance easy amplification by use of PCR.
The basis of this method is that, the entire approach entail ligation of the digested genomic DNA towards DNA. In essence, PCR primers are principally designed in a way that a single homologous is known within the target region that defines the sequence of the genomic DNA. The other homologous is to be set under a defined plasmid sequence. The major advantage however is that the conditions regarding the environment are consistent as far as air humidity as well as temperature is concerned. Additionally, the determination of the effect of relative humidity or temperature can be made only under conditions that are controlled, which a lot easier to carry out in a laboratory.