A Cryptic TriptychThree seemingly unrelated cases of PVL-associatedStaphylococcus aureus infection, their investigationand managementDominic MellonSpecialty Registrar – Public HealthSouth West (North) Health Protection Unit
Objectives• Review a series of three sporadic cases of PVL-SA• Discuss nature of the information available• Consider the role of HPZone in the investigation• Comment on issues arising from the investigation• Share learning and recommendations arising fromthis incident
Panton-Valentin Leukocidin (PVL)associated Staphylococcus aureusSource: Health Protection Agency (2011) ‘PVL-Staphylococcus aureus infections: an update’, Health Protection Report, 5(7),[online] Available from: http://www.hpa.org.uk/hpr/archives/2011/news0711.htm#pvl (Accessed 24 April 2012).
Case 1• Female student• 21 years old• Bath address/postcode, student rentedaccommodation• PVL-SA lab result reported to HPU on 8thFebruaryfollowing admission with abscess• Reporting clinician concerned that this is the thirdhousemate to be admitted, concerns around housingquality• No linked cases on HPZone
Initial investigation• No geographically/temporally linked cases of PVL-SA• Case 3 shares a postcode with a previous enquiryabout damp, mold and health effects• Environmental Health Service had been involvedpreviously• Hospital visit and interview with Case 1 and parents• Began timeline of events• Queried HPZone for housemates
Case 2 (probable index case)• Female student and food handler• 20 years old• Registered at GP practice in Hertfordshire,• Parent’s home address recorded• Recurrent boils and abscesses• Initially managed by Hertfordshire HPU• Transferred to South West (North) HPU 9thJanuary asterm time address is in Bath• No linked cases on HPZone
Case 3• Male food handler• 21 years old• South Gloucestershire postcode, lives with parents• GP reported PVL-SA positive lab result 27thJanuaryfollowing swab at hospital the previous week• Treated in hospital for abscess on buttock• Girlfriend has had similar• HPU unable to contact case• No linked cases on HPZone
Response• Visited student house to consider possible routes ofinfection• Arranged decolonisation for household contacts ofCases 1 and 2 (Case 3 already decolonised)• Provided public health/infection control advice• Did not consider further action required on the basisof housing quality
Review• Conducted a tabletop review of the investigation andresponse to identify and share learning points
Results• Over-reliance on HPZone to link cases together• Identifying linked cases may not be a straightfowardprocess and requires more than a cursoryassessment• Students may not be registered with local primarycare services or list term time addresses• Indirect transmission of the infectious agent mayhave played a significant role
Conclusions• HPZone is a powerful tool, but it is only one toolavailable to the public health professional• HPZone has significant limitations in querying data• Sometimes it is important to get out from behind thedesk and leave the office to understand the situation
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