Is Panton-Valentine leucocidin associated with the pathogenesis of Staphylococcus aureus bacteraemia in the UK?
BACKGROUND
The morbidity and mortality associated with Panton-Valentine leucocidin (PVL)-positive Staphylococcus aureus suggest that this toxin is a key marker of disease severity. Nevertheless, the importance of PVL in the pathogenesis of primary bacteraemia caused by S. aureus is uncertain. We have determined the prevalence of PVL-encoding genes among isolates of S. aureus from bacteraemic patients.


METHODS
Consecutive bacteraemia isolates of S. aureus (n=244) from patients hospitalized in 25 centres in the UK and Ireland during 2005 were screened for PVL and mecA genes. PVL-positive isolates were characterized by toxin gene profiling, PFGE, spa-typing and MIC determinations for a range of antimicrobials.


RESULTS
Four out of 244 isolates (1.6%) were PVL-positive and susceptible to oxacillin [methicillin-susceptible S. aureus (MSSA)]. Eighty-eight out of 244 (36%) were oxacillin-resistant (methicillin-resistant S. aureus), but none was PVL-positive. The four patients (two males: 30 and 33 years; two females: 62 and 80 years) had infection foci of: skin and soft tissue, unknown, indwelling line, and surgical site, and were located at one centre in Wales, one in England and two in Ireland. One of four PVL-positive isolates was resistant to penicillin and fusidic acid, the remainder were susceptible to all antibiotics tested. Genotypic analyses showed that the four isolates represented three distinct strains; the two isolates from Ireland were related.


CONCLUSIONS
We found that 1.6% of S. aureus (all MSSA) from bacteraemic patients were PVL-positive. This low incidence suggests that PVL-positive S. aureus are of no particular significance as causative agents of S. aureus bacteraemia.
Ellington
Matthew J
MJ
Staphylococcus Reference Laboratory (SRL), Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK. matthew.ellington@hpa.org.uk
Hope
Russell
R
Ganner
Mark
M
Ganner
Marjorie
M
East
Claire
C
Brick
Geraldine
G
Kearns
Angela M
AM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005098:Exotoxins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D005672:Fusidic Acid / Q000494:pharmacology; D006801:Humans; D007223:Infant; D007494:Ireland; D007956:Leukocidins / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010068:Oxacillin / Q000494:pharmacology; D010403:Penicillin Resistance / Q000235:genetics; D046915:Penicillin-Binding Proteins; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism*; D006113:United Kingdom
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus; D005672:Fusidic Acid; D010068:Oxacillin