Diversity of Listeria monocytogenes isolates from cold-smoked salmon produced in different smokehouses as assessed by Random Amplified Polymorphic DNA analyses

Vogel, Birte Fonnesbech; Jørgensen, Lasse Vigel; Ojeniyi, B.; Huss, Hans Henrik; Gram, Lone

doi:10.1016/s0168-1605(00)00503-1

Cited by 92 publications

(59 citation statements)

References 27 publications

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“…The use of both RAPD and PFGE for typing L. monocytogenes has previously been reported to identify similar groups (12,15); however, using more than one method may increase the discriminatory ability (5), which was the case in this study, albeit for a very limited number of strains. Consequently, the two DNA typing approaches should be nearly equally suitable and can efficiently differentiate strains from well-defined habitats like coldsmoked salmon processing plants I and II investigated in this study.…”

Section: Discussionmentioning

confidence: 68%

“…RAPD analysis was performed as described previously (12). Briefly, DNA was prepared with Dynabeads DYNAL DIRECT system 1 (Dynal A/S & Nordic, Oslo, Norway).…”

Section: Methodsmentioning

confidence: 99%

“…A total of 429 strains of L. monocytogenes were subsequently grouped by RAPD profiling. Concerns about the reproducibility and stability of this method have been raised (41); however, careful standardization allowed us to reproducibly obtain a high level of discrimination with this method (12). To confirm clonal separation, a subset of strains (mainly the persistent types) was also characterized by PFGE and AFLP profiling.…”

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confidence: 99%

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Elucidation of Listeria monocytogenes Contamination Routes in Cold-Smoked Salmon Processing Plants Detected by DNA-Based Typing Methods

Vogel

Huss

Ojeniyi

et al. 2001

Appl Environ Microbiol

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213

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The contamination routes of Listeria monocytogenes in cold-smoked salmon processing plants were investigated by analyzing 3,585 samples from products (produced in 1995, 1996, 1998, and 1999) and processing environments (samples obtained in 1998 and 1999) of two Danish smokehouses. The level of product contamination in plant I varied from 31 to 85%, and no L. monocytogenes was found on raw fish (30 fish were sampled). In plant II, the levels of both raw fish and product contamination varied from 0 to 25% (16 of 185 raw fish samples and 59 of 1,000 product samples were positive for L. monocytogenes). A total of 429 strains of L. monocytogenes were subsequently compared by random amplified polymorphic DNA (RAPD) profiling, and 55 different RAPD types were found. The RAPD types detected on the products were identical to types found on the processing equipment and in the processing environment, suggesting that contamination of the final product (cold-smoked salmon) in both plants (but primarily in plant I) was due to contamination during processing rather than to contamination from raw fish. However, the possibility that raw fish was an important source of contamination of the processing equipment and environment could not be excluded. Contamination of the product occurred in specific areas (the brining and slicing areas). In plant I, the same RAPD type (RAPD type 12) was found over a 4-year period, indicating that an established in-house flora persisted and was not eliminated by routine hygienic procedures. In plant II, where the prevalence of L. monocytogenes was much lower, no RAPD type persisted over long periods of time, and several different L. monocytogenes RAPD types were isolated. This indicates that persistent strains may be avoided by rigorous cleaning and sanitation; however, due to the ubiquitous nature of the organism, sporadic contamination occurred. A subset of strains was also typed by using pulsed-field gel electrophoresis and amplified fragment length polymorphism profiling, and these methods confirmed the type division obtained by RAPD profiling.

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Section: Discussionmentioning

confidence: 68%

“…RAPD analysis was performed as described previously (12). Briefly, DNA was prepared with Dynabeads DYNAL DIRECT system 1 (Dynal A/S & Nordic, Oslo, Norway).…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Elucidation of Listeria monocytogenes Contamination Routes in Cold-Smoked Salmon Processing Plants Detected by DNA-Based Typing Methods

Vogel

Huss

Ojeniyi

et al. 2001

Appl Environ Microbiol

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213

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“…Although it can be present in raw food materials, the processing plant environment is typically the immediate source of L. monocytogenes contamination of food products (5-8). Even though food processing equipment and facilities are cleaned frequently, some molecular subtypes of L. monocytogenes may persist in the food processing environment for many years (7-9).We have found that one specific molecular subtype of L. monocytogenes strains was dominant and persistent in several fish processing plants (8,10,11). Other subtypes were also isolated several times in the processing plants although not as frequently (8).…”

mentioning

confidence: 99%

Genome Sequencing Identifies Two Nearly Unchanged Strains of Persistent Listeria monocytogenes Isolated at Two Different Fish Processing Plants Sampled 6 Years Apart

Holch

Webb

Lukjancenko

et al. 2013

Appl Environ Microbiol

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117

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Listeria monocytogenes is a food-borne human-pathogenic bacterium that can cause infections with a high mortality rate. It has a remarkable ability to persist in food processing facilities. Here we report the genome sequences for two L. monocytogenes strains (N53-1 and La111) that were isolated 6 years apart from two different Danish fish processers. Both strains are of serotype 1/2a and belong to a highly persistent DNA subtype (random amplified polymorphic DNA [RAPD] type 9). We demonstrate using in silico analyses that both strains belong to the multilocus sequence typing (MLST) type ST121 that has been isolated as a persistent subtype in several European countries. The purpose of this study was to use genome analyses to identify genes or proteins that could contribute to persistence. In a genome comparison, the two persistent strains were extremely similar and collectively differed from the reference lineage II strain, EGD-e. Also, they differed markedly from a lineage I strain (F2365). On the proteome level, the two strains were almost identical, with a predicted protein homology of 99.94%, differing at only 2 proteins. No single-nucleotide polymorphism (SNP) differences were seen between the two strains; in contrast, N53-1 and La111 differed from the EGD-e reference strain by 3,942 and 3,471 SNPs, respectively. We included a persistent L. monocytogenes strain from the United States (F6854) in our comparisons. Compared to nonpersistent strains, all three persistent strains were distinguished by two genome deletions: one, of 2,472 bp, typically contains the gene for inlF, and the other, of 3,017 bp, includes three genes potentially related to bacteriocin production and transport (lmo2774, lmo2775, and the 3=-terminal part of lmo2776). Further studies of highly persistent strains are required to determine if the absence of these genes promotes persistence. While the genome comparison did not point to a clear physiological explanation of the persistent phenotype, the remarkable similarity between the two strains indicates that subtypes with specific traits are selected for in the food processing environment and that particular genetic and physiological factors are responsible for the persistent phenotype. Listeria monocytogenes is a Gram-positive, food-borne, humanpathogenic bacterium that can cause listeriosis in humans. It affects predominantly immunocompromised individuals, the elderly, young babies, and fetuses in utero (1). Although listeriosis represents only 7.4% of all reported food-borne infections, the fatality rate (17%) and hospitalization rates (92.6%) are high (2).The bacterium is common in food products and poses a special risk in ready-to-eat products that allow proliferation of the pathogen. It is not only a safety issue but also an economic concern, because 61% of food products recalled by the U.S. FDA between 1994 and 1998 were due to L. monocytogenes contamination (3). The bacterium is an intracellular human pathogen, and it also has a saprophytic life-style and can therefore be isolated fr...

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“…The incidence of L. monocytogenes in boxes and floor surfaces may have serious impact on cross-contamination of fish and it may pose a health risk. Vogel et al (2001) reported that the RAPD (random amplified polymorphic DNA) profile of L. monocytogenes that was detected in cold-smoked salmon was identical to types that were isolated on the processing equipment and in the processing environment and not to the types isolated from raw fish. It seemed that contamination of the final product was due to contamination during processing rather than to contamination from raw fish.…”

Section: Panda and Gargmentioning

confidence: 99%

Prevalence of Listeria spp. in freshwater T\s\v(Oncorhynchus my kiss and Carassius gibelio) and the environment offish markets in Northern Greece

Papadopoulos¹,

Abrahim

Sergelidis

et al. 2017

J Hellenic Vet Med Soc

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In this study, a total of 405 samples from freshwater fish, personnel and environment were collected from retail fish markets in three cities in Northern Greece and they were examined for the presence of Listeria spp. They consisted of 136 samples from the skin and 136 from the flesh of 71 rainbow trout (Oncorhynchus mykiss) and 65 gibel carps (Carassius gibelio), 20 from workers' hands, 27 from workers' knives, 22 from working surfaces, 29 from wooden boxes, 15 from plastic boxes, 18 from floor surfaces and 2 from drainage lids. Listeria spp. was isolated from 10.62% of the samples, L. monocytogenes were 0.99%, 4.69% L. seeligeri and 4.94% L. innocua, respectively. L. monocytogenes was isolated from 3.54% of the environmental samples and none from fresh water fish and workers hands' samples. Listeria spp. was isolated from 1.54% of gibel carp flesh (1.54% L. seeligeri), from 18.46% of gibel carp skin (10.77% L. seeligeri and 7.69% L. innocua) and from 8.45% from rainbow trout skin samples (1.41% L. seeligeri and 7.04% L. innocua). The higher rate of isolation of Listeria spp. from the environmental samples emphasises the importance of sanitary conditions in order to reduce the risk of contamination by L. monocytogenes at the retail level.

show abstract

Diversity of Listeria monocytogenes isolates from cold-smoked salmon produced in different smokehouses as assessed by Random Amplified Polymorphic DNA analyses

Cited by 92 publications

References 27 publications

Elucidation of Listeria monocytogenes Contamination Routes in Cold-Smoked Salmon Processing Plants Detected by DNA-Based Typing Methods

Elucidation of Listeria monocytogenes Contamination Routes in Cold-Smoked Salmon Processing Plants Detected by DNA-Based Typing Methods

Genome Sequencing Identifies Two Nearly Unchanged Strains of Persistent Listeria monocytogenes Isolated at Two Different Fish Processing Plants Sampled 6 Years Apart

Prevalence of Listeria spp. in freshwater T\s\v(Oncorhynchus my kiss and Carassius gibelio) and the environment offish markets in Northern Greece

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