Listeria monocytogenes isolated from food samples from a Romanian black market show distinct virulence profiles

Ciolacu, Luminita; Nicolau, Anca Ioana; Wagner, Martin; Rychli, Kathrin

doi:10.1016/j.ijfoodmicro.2014.08.035

Cited by 43 publications

(59 citation statements)

References 58 publications

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“…All L.monocytogenes isolates were positive to CAMP test and showed narrow zone of β-heamolysis in sheep agar, the similar results were reported by (Marrouf et al ., 2007). Regarding to the occurance of 16SrRNA genes in L.monocytogenes isolates , the obtained result revealed that , it was amplified in all seven tested isolates ,that agreed with those recorded by (Ciolacu et al .,2015) Chloramphenicol encoded by (Cat )gene was amplified in six tested isolates as in Fig. (4),that similar recorded by (Poyart-Salmeron et al,1990).…”

Section: Discussion:-supporting

confidence: 85%

Phenotypic and Genotypic Characterization of Listeria Species Isolated From Chicken and Milk Products.

Hassan¹,

Fatma²,

Hofy³

et al. 2018

IJAR

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Section: Discussion:-supporting

confidence: 85%

Phenotypic and Genotypic Characterization of Listeria Species Isolated From Chicken and Milk Products.

Hassan¹,

Fatma²,

Hofy³

et al. 2018

IJAR

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“…Among the 70 ST121 strains analyzed in our study, seven strains were human isolates. The virulence of ST121 strains is known to be attenuated primarily due a truncation in the inlA gene [7, 60–62], which has so far been reported for all ST121 strains. Two ST121 strains of our study encode a full-length InlA, among them one human isolate.…”

Section: Resultsmentioning

confidence: 99%

Comparative genomics of human and non-human Listeria monocytogenes sequence type 121 strains

et al. 2017

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The food-borne pathogen Listeria (L.) monocytogenes is able to survive for months and even years in food production environments. Strains belonging to sequence type (ST)121 are particularly found to be abundant and to persist in food and food production environments. To elucidate genetic determinants characteristic for L. monocytogenes ST121, we sequenced the genomes of 14 ST121 strains and compared them with currently available L. monocytogenes ST121 genomes. In total, we analyzed 70 ST121 genomes deriving from 16 different countries, different years of isolation, and different origins—including food, animal and human ST121 isolates. All ST121 genomes show a high degree of conservation sharing at least 99.7% average nucleotide identity. The main differences between the strains were found in prophage content and prophage conservation. We also detected distinct highly conserved subtypes of prophages inserted at the same genomic locus. While some of the prophages showed more than 99.9% similarity between strains from different sources and years, other prophages showed a higher level of diversity. 81.4% of the strains harbored virtually identical plasmids. 97.1% of the ST121 strains contain a truncated internalin A (inlA) gene. Only one of the seven human ST121 isolates encodes a full-length inlA gene, illustrating the need of better understanding their survival and virulence mechanisms.

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“…The MLST database of the Pasteur Institute in Paris, France (updated on 3 March 2015), includes only 10 ST31 strains and 69 ST121 strains (most are of the 1/2a serotype). The ST121 type has been isolated as a persistent type in food and food-associated environments in different countries (16,42,65,66). ST121 is among the six L. monocytogenes STs most prevalent worldwide (67) and seems to be well adapted to the colonization of meat-associated environments (67,68).…”

Section: Bacmentioning

confidence: 99%

“…ST121 is among the six L. monocytogenes STs most prevalent worldwide (67) and seems to be well adapted to the colonization of meat-associated environments (67,68). ST121 frequently harbors a truncated InlA, resulting in attenuated virulence (42,66). Strains of the same ST may share similarity in the genes necessary for survival in food and food processing environments (56,66).…”

Section: Bacmentioning

confidence: 99%

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The Connection between Persistent, Disinfectant-Resistant Listeria monocytogenes Strains from Two Geographically Separate Iberian Pork Processing Plants: Evidence from Comparative Genome Analysis

Ortiz

López-Alonso

Rodríguez³

et al. 2016

Appl Environ Microbiol

101

100

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The aim of this study was to investigate the basis of the putative persistence of Listeria monocytogenes in a new industrial facility dedicated to the processing of ready-to-eat (RTE) Iberian pork products. Quaternary ammonium compounds, which included benzalkonium chloride (BAC), were repeatedly used as surface disinfectants in the processing plant. Clean and disinfected surfaces were sampled to evaluate if resistance to disinfectants was associated with persistence. Of the 14 isolates obtained from product contact and non-product contact surfaces, only five different pulsed-field gel electrophoresis (PFGE) types were identified during the 27-month study period. Two of these PFGE types (S1 and S10-1) were previously identified to be persistent and BAC-resistant (BAC r ) strains in a geographically separate slaughterhouse belonging to the same company. The remaining three PFGE types, which were first identified in this study, were also BAC r . Whole-genome sequencing and in silico multilocus sequence typing (MLST) analysis of five BAC r isolates of the different PFGE types identified in this study showed that the isolate of the S1 PFGE type belonged to MLST sequence type 31 (ST31), a low-virulence type characterized by mutations in the inlA and prfA genes. The isolates of the remaining four PFGE types were found to belong to MLST ST121, a persistent type that has been isolated in several countries. The ST121 strains contained the BAC resistance transposon Tn6188. The disinfection-resistant L. monocytogenes population in this RTE pork product plant comprised two distinct genotypes with different multidrug resistance phenotypes. This work offers insight into the L. monocytogenes subtypes associated with persistence in food processing environments. Listeria monocytogenes is a Gram-positive bacterium of the phylum Firmicutes. Often found in raw foods, L. monocytogenes bacteria can cause the life-threatening disease listeriosis. Most cases of human listeriosis appear to be caused by ready-to-eat (RTE) foods, and the risk of illness increases with the number of cells ingested and with RTE foods that support the growth of L. monocytogenes (1). Processed foods can be contaminated by contact with equipment, by the handling of raw products by staff, or from postprocessing environmental niches in which L. monocytogenes can survive despite the routine use of thorough disinfection procedures (2, 3). Mechanisms that facilitate the survival of L. monocytogenes in food processing environments include biofilm formation (4, 5), acquisition of antimicrobial resistance (6-10), and stress resistance mechanisms (11,12).L. monocytogenes is capable of colonizing food production plants with certain subtypes that are found only in specific sections of the plants (13, 14). Furthermore, some of these subtypes may persist in food processing environments for years (15-17). Persistent strains have been identified to be major postprocessing contaminants of RTE foods, and in many cases, listeriosis outbreaks have been associated with cases of p...

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Listeria monocytogenes isolated from food samples from a Romanian black market show distinct virulence profiles

Cited by 43 publications

References 58 publications

Phenotypic and Genotypic Characterization of Listeria Species Isolated From Chicken and Milk Products.

Phenotypic and Genotypic Characterization of Listeria Species Isolated From Chicken and Milk Products.

Comparative genomics of human and non-human Listeria monocytogenes sequence type 121 strains

The Connection between Persistent, Disinfectant-Resistant Listeria monocytogenes Strains from Two Geographically Separate Iberian Pork Processing Plants: Evidence from Comparative Genome Analysis

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