The levels of antibodies to Panton-Valentine leukocidin (PVL) vary with PVL prevalence along a north-to-south gradient.

Recent research on Staphylococcus aureus vaccine development has focused on active immunization against Panton-Valentine leukocidin (PVL), a potent leukotoxin associated with both superficial and severe deep-seated infections. PVL prevalence is highly variable worldwide, but it is unknown to what extent immunity to PVL varies between patients from geographic areas with different PVL-positive S. aureus prevalences. We conducted a retrospective multicentric study of anti-PVL and anti-alpha-toxin (Hla) antibody levels in uninfected adult patients from France (low PVL prevalence; n = 200), Algeria (moderate prevalence; n = 143), and Senegal (high prevalence; n = 228). The antibody levels were quantified by an enzyme-linked immunosorbent assay (ELISA) procedure. Because Hla is present in virtually all S. aureus strains, its corresponding antibody levels were considered to reflect population exposure to S. aureus. Compared with French participants, the average anti-PVL antibody levels were 2.5-fold and 8.2-fold higher in Algerian and Senegalese participants, respectively (p < 0.001). Conversely, anti-Hla antibody levels did not differ between participants from the three countries, suggesting that the observed differences in anti-PVL antibody levels were not biased by variations in population exposure to S. aureus. Hence, anti-PVL antibody levels in the general populations of France, Algeria, and Senegal vary widely and match variations in PVL-positive S. aureus strain prevalence, with an increasing north-to-south gradient. To conclude, immunity to PVL in a given population correlates with local PVL prevalence. This finding can help to inform PVL vaccine strategies.

High prevalence of methicillin-resistant Staphylococcus aureus clone ST80-IV in hospital and community settings in Algiers.

USA300 is an epidemic community-acquired methicillin-resistant Staphylococcus aureus (C-MRSA) clone in the USA, whereas the European C-MRSA clone ST80-IV has mainly a sporadic diffusion in Europe. The prevalence of European clone ST80-IV in Algeria is poorly documented. We prospectively studied S. aureus infections at Mustapha Bacha hospital in Algiers over a 20-month period. S. aureus nasal colonization was studied during a further 6-month period. The European clone ST80-IV was responsible for more than one-third of both community infections (35.7%) and hospital infections (35.8%). Panton-Valentine leukocidin (PVL)-positive MRSA isolated from hospital inpatients were resistant to multiple antibiotics, including fluoroquinolones in 44.9% of cases. The PVL-positive MRSA nasal carriage rate was high among patients and staff in the dermatology unit (8.7% and 18.5%, respectively), but low (2.7%) among patients attending the outpatient clinic. The European PVL-positive C-MRSA clone ST80-IV is widespread in the Algiers hospital and community settings.

[High prevalence of community- and hospital-acquired infections of methicillin-resistant Staphylococcus aureus containing Panton-Valentine leukocidin gene in Algiers]. / Forte prévalence des infections communautaires et nosocomiales à Staphylococus aureus résistant à la méticilline et portant le gène de la leucocidine de Panton-Valentine dans l'Algérois.

OBJECTIVES: To determine the prevalence of community acquired and hospital methicillin-resistant Staphylococcus aureus (S. aureus) infections and the Panton-Valentine leukocidin. PATIENTS AND METHODS: Seven hundred S. aureus strains were collected during 21 months period in Mustapha Bacha hospital. Bacterial identification was based on standard methods and susceptibilities were tested by disk diffusion method. Molecular study (toxins, mecA gene and agr alleles) were determined for 221 S. aureus isolates by multiplex PCR. RESULTS: The global MRSA prevalence was 42 %, 35 % in the community and 49 % in hospital setting. The frequency of strains containing PVL genes (PVL+) was 36 %, their molecular profile was: agr3, mecA+, etd, edin, which correspond to the C-MRSA major ST80 clone in Europe and the Maghreb. The H-MRSA-PVL+ were multidrug resistant. Among the MSSA, 13 strains contained the tst gene and five contained the exfoliatine genes ETA and ETB. CONCLUSION: Our results show a high rate of MRSA-PVL+ in the community and the hospital setting. The H-MRSA-PVL+ were multidrug resistant complicating their antibiotic treatment options.