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Volume 2 No 31; 1 August 2008

 

S. Agona PT39: increase in new salmonella strain in UK and Ireland – an update

An increasing number of Salmonella Agona isolates showing the same undesignated phage type (PT) pattern have been received by the Health Protection Agency (HPA) Laboratory of Gastroenteric Pathogens (LGP) since February 2008. The pattern remains distinct from any currently recognised patterns in the S. Agona phage typing scheme and has been designated PT 39. It has been defined by Pulse Field Gel Electrophoresis (PFGE) profile as SAGOXB.0066. To date, LGP has confirmed 60 human cases of S. Agona PT 39 infection in residents of England, Wales and Northern Ireland. All isolates have been characterised as fully sensitive to antibiotics tested.

Cases ranged in age from one to 79 years (median 27.5 years) with 58% of cases male. Cases followed up to date have a national distribution, occurring in all Regions across England, Wales and Northern Ireland.

The HPA Centre for Infections is currently following up cases in England and Wales to determine the source of these infections. The investigation team will continue to conduct patient follow-ups.

Concurrently, Health Protection Scotland and the Health Protection Surveillance Centre of the Irish Republic have detected indigenous cases and are collaborating on a Five Nations investigation of the source of these infections.

Suspected outbreak of Salmonella Enteritidis phage type 12 infections in England and Wales

The Laboratory of Gastrointestinal Pathogens (LGP) has identified an increase in Salmonella Enteritidis PT 12 isolates, from all regions in England and Wales, above the seasonally expected value.

Between 2000 and 2007, an average of 106 (24-190) cases of S. Enteritidis PT 12 were reported to LGP annually. Between weeks one and 29, the number of reports averaged 43 (6-73) during this period. Eighty eight per cent of isolates were fully sensitive to the panel of antimicrobials tested, with 9.6% resistant to nalidixic acid and with reduced susceptibility to ciprofloxacin (NxCpL).

Between weeks 1 and 30, 2008, LGP has reported on 114 cases of non-travel-related, fully sensitive S. Enteritidis PT 12. This figure represents a significant increase on the expected number of reports for the time of year and is suggestive of an on-going outbreak (figure 1).

Figure 1. Reports of non-travel-related, fully sensitive S. Enteritidis PT 12 from England and Wales, 2008 (by LGP reception date)

Cases in 2008 have ranged in age from eight months to 94 years (median 26 years) with 54%
male. Cases reported to date have a national distribution, occurring in all Regions across England
Wales (see table).

Table. Regional distribution of S. Enteritidis PT 12 reports (1 January to 29 July 2008)

Region

All reports

All reports (rate/M*)

Follow-up cases

East Midlands

10

2.29

3

East

10

1.78

5

London

9

1.19

1

North East

3

1.17

–

North West

12

1.75

4

South East

21

2.55

4

South West

3

0.58

3

West Midlands

16

2.98

8

Yorkshire and Humberside

22

4.28

8

England subtotal

106

2.25

36

Wales

8

2.70

2

Northern Ireland

–

–

–

Total

114

–

38

* Per million population

The HPA Centre for Infections is currently following up cases reported by LGP on or after 21 July 2008. The investigation team will continue to conduct patient follow-ups and conduct trawling questionnaires.