Febrile gastroenteritis in five healthy persons was associated with the consumption of vacuum-packed cold-smoked rainbow trout containing Listeria monocytogenes. L. monocytogenes isolates from the incriminated fish product lot and the stool samples were all of serotype 1/2a and were indistinguishable by pulsed-field gel electrophoresis employing AscI and SmaI

Björkroth, K.J.

Haajanen, H.

Haajanen, P.

Heiskanen, P.

Korkeala, H.

Miettinen, M.K.

Siitonen, A.

Helsingin yliopiston digitaalinen arkisto

JOURNAL OF CLINICAL MICROBIOLOGY,0095-1137/99/$04.0010July 1999, p. 2358–2360 Vol. 37, No. 7Copyright © 1999, American Society for Microbiology. All Rights Reserved.Molecular Epidemiology of an Outbreak of Febrile GastroenteritisCaused by Listeria monocytogenes in Cold-SmokedRainbow TroutM. K. MIETTINEN,1* A. SIITONEN,2 P. HEISKANEN,3 H. HAAJANEN,4K. J. BJO¨RKROTH,1 AND H. J. KORKEALA1Department of Food and Environmental Hygiene, 00014 University of Helsinki,1 Laboratory of Enteric Pathogens,National Public Health Institute, 00300 Helsinki,2 Health Center of City of Varkaus, 78300 Varkaus,3and Varkaus Municipal Food and Environment Department, 78250 Varkaus,4 FinlandReceived 7 December 1998/Returned for modification 29 January 1999/Accepted 26 March 1999Febrile gastroenteritis in five healthy persons was associated with the consumption of vacuum-packedcold-smoked rainbow trout containing Listeria monocytogenes. L. monocytogenes isolates from the incriminatedfish product lot and the stool samples were all of serotype 1/2a and were indistinguishable by pulsed-field gelelectrophoresis employing AscI and SmaI.Listeria monocytogenes is a food-borne pathogen causing lis-teriosis mainly in immunocompromised patients (5, 8, 13). Thepredominant clinical forms of listeriosis are infections of thecentral nervous system, sepsis, abortion, and stillbirth. A diar-rheal form of disease due to the ingestion of foods contami-nated with L. monocytogenes in previously healthy persons hasalso been reported (3, 7, 11, 12). However, in only one previouscase was L. monocytogenes cultured from the implicated food,in that case from chocolate milk, characterized with pulsed-field gel electrophoresis (PFGE), and found to be identical tothe isolates from patients (3).Vacuum-packed salmon and rainbow trout have previouslybeen associated with cases of listeriosis, but not with noninva-sive gastroenteritis (4). We report febrile gastroenteritis in fivepreviously healthy persons associated with the consumptionof vacuum-packed cold-smoked rainbow trout (Onchorhyncusmykiss) containing high levels of L. monocytogenes.Two couples, aged between 39 and 52 years, and a 3-year-oldchild dined together, consuming a meal including cold-smokedrainbow trout. They had no known underlying diseases. All ofthem fell ill with gastroenteritis within the next 27 h, experi-encing nausea, abdominal cramps, and diarrhea. Three of theadults had fever (38.6 to 39.2°C). Other reported symptomswere vomiting, headache, fatigue, and arthralgia. The symp-toms lasted 3 to 4 days. The child was admitted to a hospital forone night because of vomiting, diarrhea, and fever. Based onpatient interviews and a questionnaire on the types and quan-tities of the foods consumed, the cold-smoked rainbow troutseemed to be a very likely vehicle of the pathogen that causedthe food poisoning.The patients had eaten the cold-smoked rainbow troutshortly after buying it from a retail store. The fish product hadbeen vacuum packed 17 days prior to consumption. This retailstore was visited, and the temperature of the display cabinetfor smoked fish products was measured. At the bottom of thecabinet the temperature was 4.6°C, but at the top it was 11.6°C.A vacuum-packed cold-smoked rainbow trout sample fromthe same production lot was then obtained from the sameretail store and analyzed for L. monocytogenes. Analyses wereperformed both by selective enrichment according to the meth-od of The Nordic Committee on Food Analyses (10) and byquantitative analysis for L. monocytogenes. The quantitativeanalysis was performed with Listeria enrichment broth, beforeselective supplements were added in serial dilutions on Liste-ria-selective Oxford agar.Stool samples taken on the day after the onset of the symp-toms were analyzed only for Salmonella, Shigella, Campylo-bacter, and Yersinia. Two additional stool swabs were obtainedfrom one of the couples a week after the onset of the symp-toms, and these were analyzed for L. monocytogenes by selec-tive enrichment by using the medium described above for thefish sample.Serotyping of L. monocytogenes isolates was performed ac-cording to the serotyping scheme of Seeliger and Ho¨hne (14).Commercial Listeria antisera (Denka Seiken, Tokyo, Japan)were used according to the manufacturer’s instructions withthe exception of the incubation temperature of the 0.2% brainheart infusion agar tubes, which was lowered to 26°C instead of30°C.The L. monocytogenes isolates were grown overnight in 5 mlof brain heart infusion broth at 37°C. DNA isolation was per-formed as described by Maslow et al. (9) with the modificationsdescribed previously (2). Two rare-cutting restriction enzymes,AscI and SmaI (New England Biolabs, Beverly, Mass.), wereused according to the manufacturer’s recommendations. Thesamples were run through a 1.0% (wt/vol) agarose gel (SeaKemGold; FMC Bioproducts, Rockland, Maine) in 0.53 TBE (45mM Tris, 4.5 mM boric acid [pH 8.3], and 1 mM sodiumEDTA) at 200 V at 10°C by using a Gene Navigator systemwith a hexagonal electrode (Pharmacia, Uppsala, Sweden).Macrorestriction fragments were resolved with pulse timesramping linearly from 1 to 35 s over 18 h for AscI fragmentsand from 1 to 18 s over 18 h for SmaI fragments. Lambdaladder PFG marker I and low-range PFG marker (New En-gland Biolabs) were used as fragment size markers.The cold-smoked rainbow trout sample was found to bepositive for L. monocytogenes by selective enrichment and byquantification. The fish sample contained 1.9 3 105 CFU ofL. monocytogenes per g. The storage temperature of the fishproduct at the retail outlet had been around 10°C, rather than* Corresponding author. Mailing address: Department of Food andEnvironmental Hygiene, Faculty of Veterinary Medicine, University ofHelsinki, P.O. Box 57, FIN-00014 Helsinki University, Finland. Phone:358 0 708 49 706. Fax: 358 0 708 49 718. E-mail: msjoman@vetmed.helsinki.fi.2358the range of 0 to 3°C recommended by the manufacturer. Thehigh storage temperature of the fish product probably allowedL. monocytogenes to grow to such high levels.Both of the additional stool swabs were positive for L. mono-cytogenes. Taken together with the fact that no other entericpathogens could be found, this strongly suggests that thisoutbreak of gastroenteritis among five persons was causedby L. monocytogenes. Furthermore, L. monocytogenes iso-lates from the stool swabs and the cold-smoked rainbow troutwere of serotype 1/2a and showed indistinguishable macror-estriction enzyme patterns by PFGE with both restriction en-zymes, AscI and SmaI (Fig. 1 and 2).These results provide additional supporting evidence forprevious findings that L. monocytogenes may cause febrile gas-troenteritis without invasiveness in healthy persons, if the con-sumed food is heavily contaminated with L. monocytogenes.They also show that vacuum-packed cold-smoked rainbowtrout may contain large numbers of L. monocytogenes and mustbe considered as a potential source of infection (4, 6). Thecold-smoking process does not kill L. monocytogenes (1), anddespite the cold storage of the product, growth may occur. Thesell-by date is usually around 3 weeks from the packing date;this is clearly too long, especially during the summer months.This kind of product is usually eaten without heat treatmentbefore consumption.This is, to our knowledge, the first report of febrile gastro-enteritis associated with L. monocytogenes where a fish productacted as the vehicle of the pathogen. It also shows the value ofselective enrichment for L. monocytogenes in stool samples.Without this enrichment, the Listeria might have been missed.PFGE was a very useful tool in confirming the food-borneorigin of L. monocytogenes in the cases of febrile gastroenteritispresented in this study. The study emphasizes the need to keepthe possibility of L. monocytogenes gastroenteritis in mind,especially after the presence of other enteropathogens hasbeen ruled out.This work was supported by the Technology Development Center(TEKES).REFERENCES1. Autio, T., S. Hielm, M. Miettinen, A.-M. Sjo¨berg, K. Aarnisalo, J. Bjo¨rkroth,T. Mattila-Sandholm, and H. Korkeala. 1999. Sources of Listeria monocy-togenes contamination in a cold-smoked rainbow trout processing plant de-tected by pulsed-field gel electrophoresis typing. Appl. Environ. Microbiol.65:150–155.2. Bjo¨rkroth, J., J. Ridell, and H. Korkeala. 1996. Characterization of Lacto-bacillus sake strains associating with production of ropy slime by randomlyamplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis(PFGE) patterns. Int. J. Food Microbiol. 31:59–68.3. Dalton, C. B., C. C. Austin, J. Sobel, P. S. Hayes, W. F. Bibb, L. M. Graves,B. Swaminathan, M. E. Proctor, and P. M. Griffin. 1997. An outbreak ofgastroenteritis and fever due to Listeria monocytogenes in milk. N. Engl.J. Med. 336:100–105.4. Ericsson, H., A. Eklo¨w, M.-L. Danielsson-Tham, S. Loncarevic, L.-O. Men-tzing, I. Persson, H. Unnerstad, and W. Tham. 1997. An outbreak of liste-riosis suspected to have been caused by rainbow trout. J. Clin. Microbiol. 35:2904–2907.5. Fleming, D. W., S. L. Cochi, K. L. MacDonald, J. Brondum, P. S. Hayes,B. D. Plikaytis, M. B. Holmes, A. Audurier, C. V. Broome, and A. L. Rein-gold. 1985. Pasteurized milk as a vehicle of infection in an outbreak oflisteriosis. N. Engl. J. Med. 312:404–407.6. Guyer, S., and T. Jemmi. 1991. Behavior of Listeria monocytogenes duringfabrication and storage of experimentally contaminated smoked salmon.Appl. Environ. Microbiol. 57:1523–1527.7. Heitmann, M., P. Gerner-Smidt, and O. Heltberg. 1997. Gastroenteritiscaused by Listeria monocytogenes in a private day-care facility. Pediatr. In-fect. Dis. J. 16:827–828.8. Linnan, M. J., L. Mascola, X. D. Lou, V. Goulet, S. May, C. Salminen, D. W.Hird, M. L. Yonekura, P. Hayes, R. Weaver, A. Audurier, B. D. Plikaytis,S. L. Fannin, A. Kleks, and C. V. Broome. 1988. Epidemic listeriosis asso-ciated with Mexican-style cheese. N. Engl. J. Med. 319:823–828.9. Maslow, J. N., A. M. Slutsky, and R. D. Arbeit. 1993. Application of pulsed-field gel electrophoresis to molecular epidemiology, p. 563–572. In D. H.Persing, T. F. Smith, F. C. Tenover, and T. J. White (ed.), Diagnostic mo-FIG. 1. Macrorestriction patterns of L. monocytogenes with restriction en-zyme AscI. Lane 1, lambda ladder PFG marker; lane 2, LMU1 (isolated frompatient); lane 3, LMU10 (isolated from patient); lane 4, LMK55 (isolated with-out an enrichment step from cold-smoked rainbow trout); lane 5, LMK65 (iso-lated through an enrichment step from cold-smoked rainbow trout); lane 6,low-range PFG marker.FIG. 2. Macrorestriction patterns of L. monocytogenes with restriction en-zyme SmaI. Lane 1, lambda ladder PFG marker; lane 2, LMU1 (isolated frompatient); lane 3, LMU10 (isolated from patient); lane 4, LMK55 (isolated with-out an enrichment step from cold-smoked rainbow trout); lane 5, LMK65 (iso-lated through an enrichment step from cold-smoked rainbow trout); lane 6,low-range PFG marker.VOL. 37, 1999 NOTES 2359lecular microbiology: principles and applications. American Society for Mi-crobiology, Washington, D.C.10. NCFA. 1990. L. monocytogenes. Detection in foods. Method no. 136. NordicCommittee on Food Analyses, Espoo, Finland.11. Riedo, F. X., R. W. Pinner, M. L. Tosca, M. L. Cartter, L. M. Graves, M. W.Reeves, R. E. Weaver, B. D. Plikaytis, and C. V. Broome. 1994. A point-source foodborne listeriosis outbreak: documented incubation period andpossible mild illness. J. Infect. Dis. 170:693–696.12. Salamina, G., E. Dalle Donne, A. Niccolini, G. Poda, D. Cesaroni, M. Bucci,R. Fini, M. Maldini, A. Schuchat, B. Swaminathan, W. Bibb, J. Rocourt,N. Binkin, and S. Salmaso. 1996. A foodborne outbreak of gastroenteritisinvolving Listeria monocytogenes. Epidemiol. Infect. 117:429–436.13. Schlech, W. F., P. M. Lavigne, R. A. Bortolussi, A. C. Allen, E. V. Haldane,A. J. Wort, A. W. Hightower, S. E. Johnson, S. H. King, E. S. Nicholls, andC. V. Broome. 1983. Epidemic listeriosis—evidence for transmission by food.N. Engl. J. Med. 308:203–206.14. Seeliger, H. P. R., and K. Ho¨hne. 1979. Serotyping of Listeria monocytogenesand related species. Methods Microbiol. 13:31–49.2360 NOTES J. CLIN. MICROBIOL.

Molecular epidemiology of an outbreak of febrile gastroenteritis caused by Listeria mococytogenes in cold-smoked rainbow trout

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