Typing of Methicillin resistant Staphylococcus aureus: A technical review

Abstract

Increasing prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) worldwide is a growing public health concern. MRSA typing is an essential component of an effective surveillance system to describe epidemiological trends and infection control strategies. Current challenges for MRSA typing are focused on selecting the most appropriate technique in terms of efficiency, reliability, ease of performance and cost involved. This review summarises the available information on application, potential and problems of various typing techniques in discriminating the strains and understanding the epidemiology of MRSA strains. The phenotypic methods in general are easier to perform, easier to interpret, cost effective and are widely available, however less discriminatory. The genotypic methods are expensive and technically demanding, however more discriminatory. Newer technologies involving sequencing of various genes are coming up as broadly applicable and high throughput typing systems. Still there is no consensus regarding the single best method for typing of MRSA strains. Phage typing is recommended as first line approach in epidemiological investigation of MRSA strains. PFGE remains the gold standard for characterisation of outbreak strains. DNA sequencing methods including MLST, spa typing, SCCmec typing and toxin gene profile typing are more practical methods for detecting evolutionary changes and transmission events. The choice of typing technique further depends on the purpose of the study, the facilities available and the utility of data generated to answer a desirable research question. A need for harmonisation of typing techniques by following standard protocols is emphasised to establish surveillance networks and facilitate global MRSA control.

Evaluation of LAMP Assay Using Phenotypic Tests and Conventional PCR for Detection of nuc and mecA genes Among Clinical Isolates of Staphylococcus spp

“…MRSA strains started emerging one year after the introduction of methicillin in clinical settings in 1960s [4]. The mecA gene, which encodes the low-affinity penicillin-binding protein 2a causes methicillin resistance in Staphylococci [5].…”

Παρουσία ανθεκτικών στη μεθικιλίνη Staphylococcus aureus σε γάλα και γαλακτοκομικά προϊόντα

“…In general, the phenotypic methods are easier to perform, easier to interpret, cost-effective and widely available; however they are less discriminatory. The genotypic methods are more discriminatory, but are expensive and technically demanding (Mehndiratta and Bhalla, 2012).…”

“…Most of the used methods rely on PCR mapping of cassette elements, such as the mec complex, the ccr complex and the J region (Mehndiratta and Bhalla, 2012). Until recently, eight main types of SCCmec (type I to type VIII) along with many subtypes had been distinguished among MRSA isolates.…”

“…Application of any typing method requires careful assessment of its suitability and an individual approach depending upon the purpose of the study (Mehndiratta and Bhalla, 2012).…”

Prevalence and Antibiotic Susceptibility Pattern of Methicillin-Resistant Staphylococcus Aureus (Mrsa) Isolates From Different Clinical Specimens in a Tertiary Care Hospital in Imphal

“…Apart from an understanding of the organism's epidemiology, the knowledge of prevalence and the antibiotic pattern of MRSA help the treating physicians in determining the first line of treatment in the hospitals and thus in the effective control of spread. 2 The present study was planned with an aim to determine the prevalence of MRSA from different clinical specimens viz. urine, pus, blood, sputum/throat swabs, miscellaneous (ear swabs, body fluids etc.…”