Epidemiology of methicillin-susceptible Staphylococcus aureus lineages in five major African towns: high prevalence of Panton-Valentine leukocidin genes

Abstract

The epidemiology of methicillin-susceptible Staphylococcus aureus (MSSA) in Africa is poorly documented. From January 2007 to March 2008, 555 S. aureus isolates were collected from five African towns in Cameroon, Madagascar, Morocco, Niger, and Senegal; among these, 456 unique isolates were susceptible to methicillin. Approximately 50% of the MSSA isolates from each different participating centre were randomly selected for further molecular analysis. Of the 228 isolates investigated, 132 (58%) belonged to five major multilocus sequence typing (MLST) clonal complexes (CCs) (CC1, CC15, CC30, CC121 and CC152) that were not related to any successful methicillin-resistant S. aureus (MRSA) clones previously identified in the same study population. The luk-PV genes encoding Panton-Valentine leukocidin (PVL), present in 130 isolates overall (57%), were highly prevalent in isolates from Cameroon, Niger, and Senegal (West and Central Africa). This finding is of major concern, with regard to both a source of severe infections and a potential reservoir for PVL genes. This overrepresentation of PVL in MSSA could lead to the emergence and spread of successful, highly virulent PVL-positive MRSA clones, a phenomenon that has already started in Africa.

Panton-Valentine Leukocidin-Positive Staphylococcus aureus in Ireland from 2002 to 2011: 21 Clones, Frequent Importation of Clones, Temporal Shifts of Predominant Methicillin-Resistant S. aureus Clones, and Increasing Multiresistance

“…The prevalence of pvl-positive MSSA decreased 8-fold, from 20% in 2004 to 2.5% in 2011, and it accounted for only 17% of all pvl-positive isolates identified during the study period. In contrast, in the United Kingdom, the prevalence of pvl-positive MSSA increased 9-fold between 2005 and 2010, accounting for 61.5% of all pvl-positive S. aureus in 2009 (26); in Africa, pvl-positive MSSA is also common, with 57% of MSSA isolates in one study being identified as pvl positive (27). However, MSSA isolates are not routinely referred to the Irish NMRSARL, and the number of MSSA isolates referred each year during our study was low (Table 1).…”

“…However, recent studies highlighted the complex and changing epidemiology of pvl-positive MRSA, including (i) considerable variation in the prevalence rates of pvlpositive MRSA in different regions of the world (2,17), (ii) the increasing prevalence and polyclonal population structure of pvlpositive MRSA isolates in Europe (1,21,22), (iii) the increasing prevalence of ST8-MRSA-IV in Europe and the decreasing prevalence of ST80-MRSA-IV (21), (iv) the increasing prevalence of multiresistant pvl-positive MRSA (22), and (v) the spread of pvlpositive MRSA into hospitals (14,(23)(24)(25). Furthermore, there has been an increasing frequency of reports of infections associated with pvl-positive MSSA (26,27) that produce similar clinical presentations as pvl-positive MRSA, and the former are a potential reservoir for the emergence of pvl-positive MRSA.…”

Clonal lineages detected amongst tetracycline-resistant meticillin-resistant Staphylococcus aureus isolates of a Tunisian hospital, with detection of lineage ST398

“…Therefore, in the 1990s, CC8 (ST239) was extended from South America to Europe and from Thailand to China (Gray et al, 2011). Data from Africa are still limited, but also indicate a predominance of CC8 (ST239 and the infrequently described ST612), CC5 (ST5) and CC30 (ST36) lineages in Africa (Jansen van Rensburg et al, 2011;Breurec et al, 2011;Moodley et al, 2010). It is important to note that other CCs detected in our study (other than CC398), have also been detected in livestock animals; this is the case for CC5 and CC8 (Smith, 2015).…”

Molecular Characterization and Panton-Valentine Leucocidin Typing of Community-Acquired Methicillin-Sensitive Staphylococcus aureus Clinical Isolates

“…A nonsynonymous mutation at position 527, however, serves as the basis of the H and R isoforms (2,12,22,28). Currently, though most research is focused on PVL-positive MRSA (PVL-MRSA), a rising incidence of PVL-positive, methicillin-sensitive S. aureus (PVL-MSSA) infections reported recently is the main contributing factor in the increased incidence of PVL-positive strains in some locales, with approximately 60% of total PVL-positive S. aureus isolates in England in the past 5 years found to be susceptible to methicillin (6,16,29). With clinical and epidemiological characteristics similar to those of CA-MRSA (9,25), PVL-MSSA may represent a hitherto-unrecognized, overlooked emerging public health threat.…”