Abstract
The SCCmec element is one of the recommended targets for MRSA characterization and several multiplex-PCR SCCmec typing methods have been developed over the past years. However, there are no data on the consistency of the SCCmec types in clinical isolates as detected by these methods. Using different previously published, commonly used M-PCR methods, this report describes the diversity of SCCmec elements in MRSA isolates in the Pretoria region of South Africa and the discrepancies observed in the assigned SCCmec types. Different SCCmec types were assigned to the same clinical MRSA isolates. The discrepancies included the assignment of composite SCCmec types [(SCCmec II and SCCmecury) 20.7% (40/193)] and [(SCCmec type II+IVc) 22.3% (43/193)] to some of the clinical MRSA isolates. Summarily, the combination of the result of the M-PCR methods showed that the MRSA genotypes circulating in the healthcare facility studied potentially carried SCCmec types I, II, IV (subtypes IVa, IVb and IVd) and V. No SCCmec types III or VIII was detected among the isolates. At least 25.91% of SCCmec type IV was detected in this study, thus corroborating previous findings of the global encroachment of MRSA strains into the hospital settings. The associated epidemiological significance of these observations is discussed and we also call for an African consensus SCCmec typing method in order to allow effective epidemiological data comparison across the countries. Key words: MRSA genotype, SCCmec elements, multiplex-polymerase chain reaction (PCR), variation.
Highlights
Epidemiological history shows that, the CA-MRSA differed from the Healthcare-associated MRSA (HA-MRSA) in various ways: (i) the lack of traditional risk factors associated with MRSA among patients, (ii) a susceptibility pattern with resistance to few antimicrobial agents and (iii) the inclusion of specific virulence factors such as the Panton Valentine leucocidin (PVL) genes (Weber, 2005; Lo et al, 2011)
The electrophoretic pattern of the M-polymerase chain reaction (PCR) amplicons used for the assignment of the staphylococcal cassette chromosome mec elements (SCCmec) types is shown in supplementary material (Figure S1-S7)
An attempt to categorize the SCCmec types defined by each SCCmec typing method in this study revealed that there was no specific distribution pattern of SCCmec type(s) among the pulsed field gel electrophoresis derived pulsotypes suggesting that there was no specific association between the chromosomal DNA content of the MRSA isolates and the SCCmec type assigned by the methods evaluated
Summary
The lack of healthcare associated risk factors for the definition of CAMRSA as prescribed by the Centers for Disease Control and Prevention (CDC) (Morrison et al, 2006) was not sufficient in defining the emergence of CA-MRSA- and HA-MRSA-associated infection in the community and the association of CA-MRSA strains with healthcareassociated infections (O‟Brien et al, 1999; Saiman et al, 2003) This led to the use of molecular typing tools (based on SCCmec element) for the classification of MRSA (Daum et al, 2002; Naimi et al, 2003). To circumvent the inherent limitations of individual SCCmec typing methods, five published M-PCR based SCCmec typing were combined in order to determine the diversity of SCCmec elements in the Pretoria region of South Africa and to observe the differences in the SCCmec types assigned by methods that detect the same range of known SCCmec types
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
