National Salmonella Reference Laboratory (NSRL)

1. National Salmonella Reference Laboratory(NSRL) C. O’ Hare, N. Delappe, G. Doran, D. Morris, D. Kilmartin, ,A. Lawlor Capt. P. Scarlett, M. Cormican, and G. Corbett-Feeney Department of Bacteriology Clinical Science Institute National University of Ireland, Galway Tel: 353-91-544628 Fax: 353-91-512514

2. Abstract • The National Salmonella Reference Laboratory (NSRL) was established in January 2000 with funding through the Western Health Board from the Department of Health and Children. Dr.Tom Moffat, Minister for State, officially launched the service in March 2000. The service is provided from the laboratory of the Department of Bacteriology, National University of Ireland, Galway on an interim basis pending a decision as to the need for, and location of, a definitive National Salmonella Reference Laboratory. • The NSRL adds a national public health dimension in support of the work of the country’s clinical laboratories. The laboratory assists in the epidemiology and surveillance of Salmonella enterica isolates by the routine testing of serotyping, extended antimicrobial susceptibilites, phage typing and molecular analysis of submitted isolates. By assembly of all Salmonella enterica isolates in a single laboratory, the NSRL facilitates recognition and confirmation of links between individual cases of infection, even where outbreaks are widely dispersed. This poster summarises the progress of the NSRL in 2001 and outlines potential issues for the future.

3. IntroductionSalmonella infection is a significant global public health problem. The species of bacterium associated with salmonellosis is Salmonella enterica , of which there are more than 2000 serotypes. The Salmonella enterica serotypes associated with gastroenteritis in humans are often present in the gastrointestinal tract of animals including animals intended for human consumption. The primary source of human infection is by transfer from animals to humans through the food chain, although person-to-person transfer may also occur. Most cases of human infection with salmonella are associated with an acute self-limiting gastrointestinal illness, characterised by diarrhoea, abdominal cramps, fever and vomiting. However, in a proportion of cases, especially among the very young, the elderly and those with impaired immune function, the bacteria may invade the blood stream and cause very serious life-threatening infection. The NSRL provides an overview of the epidemiology and burden of disease caused by salmonella infection in Ireland today. Another important role of the NSRL is the extended sensitivity testing of salmonella isolates. Resistance of bacteria to antibiotics is an increasing concern throughout the world and laboratory susceptibility testing of isolates is important both as a guide to the therapy of individual patients and as an indicator of the nature and extent of the problem of resistance. Comprehensive standardised antimicrobial sensitivity testing and molecular techniques are also applied to strains to determine how closely bacteria are related.

4. Introduction • Salmonella enterica is a global health problem • >2000 serotypes • The primary source of human infection is by transfer from animals to humans through the food chain • Mostly illness is acute self-limiting gastroenteritis • But can be fatal in old/young or immunosuppressed • Isolation • Clinical: Faeces plated onto Xylose lysine deoxycholate (XLD) • selective agar, 37oC. • Food: Enrichment in peptone water • Subculture to Selective enrichment RVB or Selenite • Plate on selective XLD or BGA media, all 37oC

5. Materials and Methods • Serotyping: - performed by slide agglutination using commercial standard antisera, according to the Kauffmann-White classification scheme • Antibiotic Sensitivity testing: - performed by the NCCLS disk-diffusion method against a panel of 15 antimicrobial agents. • Phage typing: - performed on all S.Typhimurium and S.Enteritidis isolates using the overlay/ lysis method developed by PHLS, Colindale, UK. • Pulsed Field Gel Electrophoresis: - molecular analysis according to standard guidelines by PulseNet, CDC, USA.

6. Serotypes of Salmonella enterica in Ireland in 2001

7. Phage Typing Phage lysis areas on a plate overlayed with Salmonella Typhimurium culture, indicate a specific pattern with is referred to as a Phage type.

8. Pulse Field Gel Electrophoresis (PFGE) PFGE analysis of XbaI -digested genomic DNA from phage types of Salmonella Typhimurium

9. Quality Assurance • NSRL is committed to ensuring the highest possible quality of service and rapid turnaround. Reports are issued on most isolates within 5 days. In the case of isolates that present particular difficulty an interim report is issued initially and a final report on completion. • NSRL participates in a European proficiency testing scheme for serotyping, phage typing and antibiotic susceptibility testing. • The laboratory collaborates closely with the Laboratory of Enteric pathogens in London. All phage types that have not previously been detected or which yield unidentified patterns are sent there for confirmation. • The NSRL aspires to accreditation to provide assurance of its quality of service and is involved in a pilot project with the National Accreditation Board to achieve NAB accreditation.

10. Dissemination of Information • Accumulated data is e-mailed to National Disease Surveillance Centre, Food Safety Authority of Ireland and clinical microbiologists each month. • NDSC publishes updated summary tables in publication Epi-Info each month • NSRL is linked to the pan-European network Enternet through which summary data is provided monthly to a coordinator in the UK. Through this network, information and isolates for study have been shared with colleagues in other countries who are investigating particular incidents or concerns. • A pilot project to transmit results via encrypted e-mail is being discussed with the NDSC.

11. Research • It is important that a Reference Laboratory should be a focus of research and development to ensure it can respond rapidly to new developments in its field of expertise • A number of Salmonella serotypes are currently under research focus with regard to molecular analysis (PFGE and Plasmids). These include: S. Typhimurium, S. Enteritidis, S. Kentucky, S. Kedougou and S. Bredeney (the latter in association with Dr.S.Fanning, C.I.T., and Dr.J.Moore, PHLS, N.Ireland). • In collaboration with other groups, NSRL is operating a pilot study of PFGE and PCR typing methods for Shigella sonnei, Listeria monocytogenes, Campylobacter sp. and E.coli O157, and hope to offer a molecular typing service for S.sonnei in 2003. • A research ethos is maintained in the NSRL by close association with the Dept. of Bacteriology in NUIG, e.g. the study of ESBL’s, and also flouroquinolone resistance in Salmonella serotypes

12. Martin --Acknowledgements ??? Shea Fanning, PHLS Colindale FSAI NDSC Jim Moore Cyril Carroll ? ? ?