National Salmonella Reference Laboratory NSRL

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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 [phone]
• Fax [phone]

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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 countrys 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.

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Introduction Salmonella 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.
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Introduction

• Salmonella enterica is a global health problem
• gt2000 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

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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.

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Serotypes of Salmonella enterica in Ireland in
2001
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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.
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Pulse Field Gel Electrophoresis (PFGE)
PFGE analysis of XbaI -digested genomic DNA from
phage types of Salmonella Typhimurium
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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.

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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.

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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 ESBLs, and also
  flouroquinolone resistance in Salmonella serotypes

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