PVL MRSA a Problem in Mali

Link: The carriage population of Staphylococcus aureus from Mali is composed of a combination of pandemic clones and the divergent PVL positive genotype ST152 -- Ruimy et al., 10.1128/JB.01947-07 -- The Journal of Bacteriology.

Staphylococcus aureus is an important human pathogen, but asymptomatic colonisation of the naso-pharynx is far more common than cases of invasive disease. Evidence concerning the global population structure of S. aureus is limited by the over-representation in the database of disease isolates recovered from Western Europe, the Americas, Australia and Japan. We address this by presenting data from the carriage population in Mali, the first detailed characterisation of asymptomatic carriage from an African population. These data confirm the pandemic spread of many of the common S. aureus clones in the carriage population. We also note the high frequency (~24%) of a single divergent genotype, ST152, which has not previously been recovered from nasal carriage, but which corresponds to a sporadic PVL positive CA-MRSA clone noted in mostly in central Europe. We show that 100% of the ST152 isolates recovered from nasal carriage in Mali are PVL positive and discuss implications relating to the emergence and spread of this virulent genotype.