Abstract:
INTRODUCTION
We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends
and molecular epidemiology trends of S. aureus bacteraemia (SAB).
METHODS
Thirteen academic centres in South Africa were included from June 2010 until July 2012. S.
aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR
using the LightCycler 480 II was done for mecA and nuc. SCCmec and spa-typing were
finalized with conventional PCR. We selected one isolate per common spa type per province
for multilocus sequence typing (MLST).
RESULTS
S. aureus from 2709 patients were included, and 1231 (46%) were resistant to methicillin,
with a significant decline over the three-year period (p-value = 0.003). Geographical distribution
of MRSA was significantly higher in Gauteng compared to the other provinces
(P<0.001). Children <5 years were significantly associated with MRSA with higher rates
compared to all other age groups (P = 0.01). The most prevalent SCCmec type was
SCCmec type III (531 [41%]) followed by type IV (402 [31%]). Spa-typing discovered 47 different
spa-types. The five (87%) most common spa-types were t037, t1257, t045, t064 and
t012. Based on MLST, the commonest was ST612 clonal complex (CC8) (n = 7) followed by
ST5 (CC5) (n = 4), ST36 (CC30) (n = 4) and ST239 (CC8) (n = 3).
CONCLUSIONS
MRSA rate is high in South Africa. Majority of the isolates were classified as SCCmec type
III (41%) and type IV (31%), which are typically associated with hospital and community-acquired
infections, respectively. Overall, this study reveals the presence of a variety of hospital-
acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257.
Monitoring trends in resistance and molecular typing is recommended to detect changing
epidemiological trends in AMR patterns of SAB.
