EMERGING INFECTIOUS DISEASES

Microbiologist
Wanda Manley
Phone: 307-777-8680

Epidemiology and Laboratory Capacity Grant Program
The Wyoming Public Health Laboratory is participating in the CDC-sponsored "Epidemiology and Laboratory Capacity for Infectious Diseases" program. This initiative involves a nationwide set of multi-year grants to state public health departments to strengthen their capability to detect and respond to current and emerging disease problems. Within the Wyoming State Health Laboratory (WPHL) there are four major areas of focus:

1. Detect and identify agents of food-borne illnesses Food-borne disease investigation
2. Improve the ability of the laboratory to serologically identify Salmonella isolates in order to epidemiologically trace outbreaks Salmonella Serotyping
3. Institute a DNA-based system that determines the relatedness of isolates within a bacterial species Pulsed Field Gel Electrophoresis (PFGE)
4. Develop confirmatory antibiotic testing for selected bacteria of epidemiological significance.  This Antimicrobial Susceptibility testing is done in the Bacteriology Laboratory.

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 Food-borne disease investigation
Suspected food-borne disease outbreaks should be referred initially to your local public health department and the Wyoming Public Health Epidemiology Unit (307-888-996-9104). An outbreak is defined as three or more people from different households that developed the same illness after ingesting the same food. Only foods implicated in a food borne outbreak will be tested for pathogens and clinical samples should accompany food samples when possible. All sample collection must be coordinated between the local health department and/or sanitarian and WPHL. After the initial investigation is completed, testing will be determined based on symptoms and incubation times for suspected food pathogens.  For specific information on diagnosis and treatment of food-borne illness the Morbidity and Mortality Weekly Report (MMWR) from April 16, 2004 53 (RR04)is an excellent resource.  A chart of symptomology and onset time frames for a variety of pathogenic agents is included (page 7) in the publication. 

Specimen Requirements
1. Submit 50 grams for each food suspected in sterile whirl-pak containers.
2. Food should be collected from the source if possible.
3. Two forms must accompany each food sample; the Bacteriology Form and the Food Sample Collection Report.

Shipment of samples
1. Food should be shipped on ice packs, frozen food should be shipped in its frozen state.
2. Shipment should be overnight or second day delivery.

Criteria for rejection

1. Samples shipped improperly.

2. Samples not meeting the case definition.

3. Foods not implicated based on incubation periods and symptoms.

Reporting/Interpretation

1. Enterotoxin production will be reported for Clostridium perfringens, Staph. aureus, and Bacillus cereus.

2. Presence or absence of Salmonella, Shigella, Listeria, Campylobacter and Vibrio is reported.

3. If isolated, Salmonella, Shigella, Listeria and E. coli O157:H7 will be serotyped.

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Salmonella Serotyping
1. All Salmonella isolates are required to be sent to the WPHL for serotyping.  
2. Salmonella isolates will be typed with somatic (O) antigents and flagellar (H) antigens. 
3. Serotyping may be useful, epidemiologically, to relate cases in an outbreak situation.

Specimen Requirements
1. A pure isolate of the Salmonella is required for serotyping.
2. Cultures should be accompanied by a bacteriology form filled out completely.

Shipment
Specimens should be shipped according to the federal postal regulations for etiological agents.

Criteria for rejection
1. Non-viable cultures
2. Organisms other than the specified genus.
3. Contaminated cultures.

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Reporting/Interpretation
1. Preliminary report will include serogroup.
2. Final report will include serotype.
3. Naming of salmonella serotypes has gone through recent revisions by the CDC. Salmonella now consists of two species: enterica and bongori. Enterica has 6 subspecies; enterica , salamae, arizonae, diarizonae, houtenae, indica. Each subspecies has serovars (serotypes) within it. .

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Pulsed Field Gel Electrophoresis (PFGE)
Pulsed Field Gel Electrophoresis (PFGE)is a molecular technique to determine genetic relatedness within a single bacterial species. PFGE is used by the WPHL to evaluate bacterial isolates suspected of being part of an outbreak or cluster of disease in the state or at a facility. Used primarily with food-borne bacterial pathogens PFGE is also useful in nosocomial outbreak situations to determine if isolates from different patients or sources are related. PFGE could provide valuable information on the relatedness of multiple isolates of a species of bacteria recovered from different patients within a specific time period from a unit or floor of a medical facility.  Isolates submitted to the Public Health Laboratory as part of the Reportable Disease program will be tested. Gel patterns will be entered into Pulse Net, the national database that does comparisons to other similar strains recovered across the nation.

PFGE is available for the following species:
1. E. coli, including E.coli 0157:H7
2. Listeria
3. Salmonella
4. Shigella
5. Campylobacter
6. Methicillin-Resistant Staphylococcus aureus (MRSA)

Shipment
Specimens should be shipped according to the federal postal regulations for etiological agents.

Criteria for rejection
1. Non-viable cultures
2. Organisms other than the specified genus.
3. Contaminated cultures.