scholarly journals Temperature-Dependent Phage Resistance of Listeria monocytogenes Epidemic Clone II

2009 ◽  
Vol 75 (8) ◽  
pp. 2433-2438 ◽  
Author(s):  
Jae-Won Kim ◽  
Sophia Kathariou
Keyword(s):  
Listeria Monocytogenes ◽  
The United States ◽  
Phage Resistance ◽  
Processing Plant ◽  
Broad Host Range ◽  
Temperature Dependent ◽  
Cadmium Resistance ◽  
Epidemic Clone ◽  
Plant Environment ◽  
Serotype 4B

ABSTRACT Listeria monocytogenes epidemic clone II (ECII) has been responsible for two multistate outbreaks in the United States in 1998-1999 and in 2002, in which contaminated ready-to-eat meat products (hot dogs and turkey deli meats, respectively) were implicated. However, ecological adaptations of ECII strains in the food-processing plant environment remain unidentified. In this study, we found that broad-host-range phages, including phages isolated from the processing plant environment, produced plaques on ECII strains grown at 37°C but not when the bacteria were grown at lower temperatures (30°C or below). ECII strains grown at lower temperatures were resistant to phage regardless of the temperature during infection and subsequent incubation. In contrast, the phage susceptibility of all other tested strains of serotype 4b (including epidemic clone I) and of strains of other serotypes and Listeria species was independent of the growth temperature of the bacteria. This temperature-dependent phage susceptibility of ECII bacteria was consistently observed with all surveyed ECII strains from outbreaks or from processing plants, regardless of the presence or absence of cadmium resistance plasmids. Phages adsorbed similarly on ECII bacteria grown at 25°C and at 37°C, suggesting that resistance of ECII strains grown at 25°C was not due to failure of the phage to adsorb. Even though the underlying mechanisms remain to be elucidated, temperature-dependent phage resistance may represent an important ecological adaptation of L. monocytogenes ECII in processed, cold-stored foods and in the processing plant environment, where relatively low temperatures prevail.

scholarly journals DNA Probes for Unambiguous Identification of Listeria monocytogenes Epidemic Clone II Strains

2010 ◽  
Vol 76 (9) ◽  
pp. 3061-3068 ◽  
Author(s):  
Ying Cheng ◽  
J.-W. Kim ◽  
S. Lee ◽  
R. M. Siletzky ◽  
S. Kathariou
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
The United States ◽  
Dna Probes ◽  
Epidemic Clone ◽  
Clonal Group ◽  
Food Borne ◽  
Serotype 4B

ABSTRACT Listeria monocytogenes epidemic clone II (ECII) strains have been responsible for two major multistate outbreaks of food-borne listeriosis in the United States, but their prevalence and ecology remain poorly understood. In this study, we describe DNA probes that unambiguously identify this clonal group. These probes were able to differentiate ECII strains of outbreak, sporadic, or environmental origin from other L. monocytogenes strains of the same serotype (4b).

scholarly journals A Novel Restriction-Modification System Is Responsible for Temperature-Dependent Phage Resistance in Listeria monocytogenes ECII

2012 ◽  
Vol 78 (6) ◽  
pp. 1995-2004 ◽  
Author(s):  
Jae-Won Kim ◽  
Vikrant Dutta ◽  
Driss Elhanafi ◽  
Sangmi Lee ◽  
Jason A. Osborne ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Low Temperatures ◽  
Phage Resistance ◽  
Type Ii ◽  
Temperature Dependent ◽  
Epidemic Clone ◽  
Modification System ◽  
Content Type ◽  
Restriction Modification System ◽  
Restriction Modification

ABSTRACTListeria monocytogenesepidemic clone II (ECII) strains are unusual in being completely resistant to phage when grown at low temperatures (≤30°C). In the current study we constructed and characterized amariner-based mutant (J46C) of the ECII strain H7550-CdSthat lacked temperature-dependent resistance to phage. The transposon was localized in LMOh7858_2753 (open reading frame [ORF] 2753), a member of a 12-ORF genomic island unique to ECII strains. ORF 2753 and ORF 2754 exhibited homologies to restriction endonucleases and methyltransferases associated with type II restriction-modification (RM) systems.In silico-based predictions of the recognition site for this putative RM system were supported by resistance of DNA from ECII strains to digestion by BfuI, a type II restriction enzyme specific for GTATCC (N6/5). Similarly to J46C, a mutant harboring an in-frame deletion of ORF 2753 was susceptible to phage regardless of temperature of growth (25°C or 37°C). Genetic complementation restored phage resistance in 25°C-grown cells of ORF 2753 mutants. Reverse transcription (RT) and quantitative real-time PCR data suggested enhanced transcription of ORF 2753 at low temperatures (≤25°C) compared to 37°C. In contrast, available transcriptional data suggested that the putative methyltransferase (ORF 2754) was constitutively expressed at all tested temperatures (4 to 37°C). Thus, temperature-dependent resistance ofL. monocytogenesECII to phage is mediated by temperature-dependent expression of the restriction endonuclease associated with a novel RM system (LmoH7) unique to this epidemic clone.

scholarly journals Molecular serotyping and identification of the 85M gragment in different Colombian isolates of Listeria monocytogenes strains: A descriptive study

2012 ◽  
pp. 38-45
Author(s):  
María Consuelo Vanegas ◽  
Mayra Viviana Medrano ◽  
Aida Juliana Martínez ◽  
Stefany Alejandra Arévalo
Keyword(s):  
Listeria Monocytogenes ◽  
Clinical Samples ◽  
Processing Plant ◽  
Epidemic Clone ◽  
Standardized Protocol ◽  
Plant Equipment ◽  
Serotype 4B ◽  
Serotype Identification ◽  
And Control

Introduction: Listeria monocytogenes is a pathogen acquired through the consumption of contaminated foods. Thirteen serotypes have been reported, of which 1/2a, 1/2b, and 4b are responsible for 98% of human listeriosis cases. This study examines the association between serotypes and virulent clones, offering greater information and providing tools to prevent and control diseases caused by L. monocytogenes serotype 4b. Objective: To identify the serotypes from L. monocytogene strains isolated from different samples by performing the molecular subtyping technique; to determine the 85M fragment that codifies for epidemic clone I. Methods : 108 strains of L. monocytogenes were used, isolated from samples of animals, body fluids, foods, and food processing plant equipment and spaces. The samples were identified by following the Bacteriological Analytical Manual protocol described by the Food and Drug Administration (FDA). The strains were identified by Polymerase Chain Reaction (PCR) using primers and a standardized protocol from a previous research project. Serotype identification was performed by multiplex PCR. The determination of the 85M fragment of the SSCS cassette was done by following the protocol by Yildrim et al. Results : Of the 108 L. monocytogenes strains analyzed, 60.2% (65 strains) belonged to the 4b-4d-4e serotype, 17.6% (19 strains) were identified as 1/2a-3a serotype, 14.8% (16 strains) were 4a-4c serotype, 3.7% (4 strains) belonged to the 1/2c-3c serotype, and (3.7%) corresponded to the 1/2b-3b-7 serotype. It was determined that the L. monocytogenes strains serotype 4b-4d-4e and 1/2a-3b have the 85M fragment of the SSCS cassette. Conclusion : This study reports the predominant existence of L. monocytogenes strains serotype 4b-4d-4e in food, environmental, and clinical samples. The presence of an epidemic clone I region was also found in L. monocytogenes strains.

scholarly journals Diverse Cadmium Resistance Determinants in Listeria monocytogenes Isolates from the Turkey Processing Plant Environment

2009 ◽  
Vol 76 (2) ◽  
pp. 627-630 ◽  
Author(s):  
S. Mullapudi ◽  
R. M. Siletzky ◽  
S. Kathariou
Keyword(s):  
Listeria Monocytogenes ◽  
Benzalkonium Chloride ◽  
Processing Plant ◽  
Cadmium Resistance ◽  
Resistance Determinants ◽  
Plant Environment ◽  
Processing Plants

ABSTRACT Two different cadA cadmium resistance determinants (cadA1, first identified in Tn5422, and cadA2, associated with pLM80) were detected among cadmium-resistant Listeria monocytogenes strains from turkey processing plants. Prevalence of cadA1 versus cadA2 was serotype associated. Cadmium-resistant isolates that were also resistant to benzalkonium chloride (BC) were more likely to harbor cadA2 alone or together with cadA1 than isolates that were cadmium resistant but BC susceptible.

scholarly journals Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States

2008 ◽  
Vol 74 (21) ◽  
pp. 6623-6630 ◽  
Author(s):  
Jae-Won Kim ◽  
Robin M. Siletzky ◽  
Sophia Kathariou
Keyword(s):  
United States ◽  
Host Range ◽  
Environmental Samples ◽  
The United States ◽  
Host Cells ◽  
Processing Plant ◽  
Wide Host Range ◽  
Plant Environment ◽  
Processing Plants ◽  
Serotype 4B

ABSTRACT Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.

Traceback Identification of an Ingredient (Pork Dewlap) as the Possible Source of Listeria monocytogenes Serotype 4b Contamination in Raw Chicken Products

2007 ◽  
Vol 70 (6) ◽  
pp. 1513-1517 ◽  
Author(s):  
VICTORIA LÓPEZ ◽  
SAGRARIO ORTIZ ◽  
ALFREDO CORUJO ◽  
PILAR LÓPEZ ◽  
JAIME NAVAS ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Restriction Analysis ◽  
Virulence Gene ◽  
Pulsed Field Gel Electrophoresis ◽  
Processing Plant ◽  
Poultry Processing ◽  
Serotype 4B ◽  
Fresh Products ◽  
Allelic Analysis

In surveys conducted on finished product samples from a single poultry processing plant in Spain, Listeria monocytogenes was found in 14 different uncooked products. To track contamination patterns, 77 L. monocytogenes isolates were characterized by PCR-based serotyping, pulsed-field gel electrophoresis (PFGE) restriction analysis, and PCR-based allelic analysis of the virulence gene actA. Serotyping revealed that 12 isolates (15.6%) were of the L. monocytogenes serotype 4b complex (serotype 4b or the closely related serotypes 4d and 4e). A combination of endonucleases AscI and ApaI PFGE patterns yielded 15 different pulsotypes among all 77 tested isolates. All the serotype 4b isolates belonged to one pulsotype. Sequencing of the actA gene confirmed that all serotype 4b isolates corresponded to the same allelic subtype. The subtype was recovered from five product types, but its presence was not correlated with the production line or the date of isolation, suggesting a possible association of this strain with a common ingredient. This traceback investigation established that pork dewlap, an ingredient common to all the products contaminated with this strain, was the most probable source of L. monocytogenes 4b. The same 4b strain was isolated from four samples of pork dewlap from one specific supplier. After replacement of this contaminated ingredient in the fresh products, this strain of L. monocytogenes serotype 4b was not detected. This study confirms the effectiveness of molecular subtyping to control contamination by specific strains of L. monocytogenes and the importance of testing the different ingredients added to the food products.

scholarly journals Conservation of Genomic Localization and Sequence Content of Sau3AI-Like Restriction-Modification Gene Cassettes among Listeria monocytogenes Epidemic Clone I and Selected Strains of Serotype 1/2a

2010 ◽  
Vol 76 (16) ◽  
pp. 5577-5584 ◽  
Author(s):  
Suleyman Yildirim ◽  
Driss Elhanafi ◽  
Wen Lin ◽  
Anthony D. Hitchins ◽  
Robin M. Siletzky ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gene Cassette ◽  
Conclusive Evidence ◽  
Gene Encoding ◽  
Epidemic Clone ◽  
Food Borne ◽  
Serotype 1 ◽  
Serotype 4B ◽  
Clonal Population Structure ◽  
Restriction Modification

ABSTRACTListeria monocytogenesis a food-borne pathogen with a clonal population structure and apparently limited gene flow between strains of different lineages. Strains of epidemic clone I (ECI) have been responsible for numerous outbreaks and invariably have DNA that is resistant to digestion by Sau3AI, suggesting methylation of cytosine at GATC sites. A putative restriction-modification (RM) gene cassette has been identified in the genome of the ECI strain F2365 and all other tested ECI strains but is absent from other strains of the same serotype (4b). Homologous RM cassettes have not been reported amongL. monocytogenesisolates of other serotypes. Furthermore, conclusive evidence for the involvement of this RM cassette in the Sau3AI resistance phenotype of ECI strains has been lacking. In this study, we describe a highly conserved RM cassette in certain strains of serotypes 1/2a and 4a that have Sau3AI-resistant DNA. In these strains the RM cassette was in the same genomic location as in the ECI reference strain F2365. The cassette included a gene encoding a putative recombinase, suggesting insertion via site-specific recombination. Deletion of the RM cassette in the ECI strain F2365 and the serotype 1/2a strain A7 rendered the DNA of both strains susceptible to Sau3AI digestion, providing conclusive evidence that the cassette includes a gene required for methylation of cytosine at GATC sites in both strains. The findings suggest that, in addition to its presence in ECI strains, this RM cassette and the accompanying genomic DNA methylation is also encountered among selected strains of other lineages.

scholarly journals Heavy Metal and Disinfectant Resistance of Listeria monocytogenes from Foods and Food Processing Plants

2012 ◽  
Vol 78 (19) ◽  
pp. 6938-6945 ◽  
Author(s):  
Shakir S. Ratani ◽  
Robin M. Siletzky ◽  
Vikrant Dutta ◽  
Suleyman Yildirim ◽  
Jason A. Osborne ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Cadmium Resistance ◽  
Content Type ◽  
Ecological History ◽  
Resistance Determinants ◽  
Processing Plants ◽  
History Of ◽  
Serotype 4B

ABSTRACTThe persistence ofListeria monocytogenesin food processing plants and other ecosystems reflects its ability to adapt to numerous stresses. In this study, we investigated 138 isolates from foods and food processing plants for resistance to the quaternary ammonium disinfectant benzalkonium chloride (BC) and to heavy metals (cadmium and arsenic). We also determined the prevalence of distinct cadmium resistance determinants (cadA1,cadA2, andcadA3) among cadmium-resistant isolates. Most BC-resistant isolates were resistant to cadmium as well. Arsenic resistance was encountered primarily in serotype 4b and was an attribute of most isolates of the serotype 4b epidemic clonal group ECIa. Prevalence of the known cadmium resistance determinants was serotype associated:cadA1was more common in isolates of serotypes 1/2a and 1/2b than 4b, whilecadA2was more common in those of serotype 4b. A subset (15/77 [19%]) of the cadmium-resistant isolates lacked the known cadmium resistance determinants. Most of these isolates were of serotype 4b and were also resistant to arsenic, suggesting novel determinants that may confer resistance to both cadmium and arsenic in these serotype 4b strains. The findings may reflect previously unrecognized components of the ecological history of different serotypes and clonal groups ofL. monocytogenes, including exposures to heavy metals and disinfectants.

Growth of Listeria monocytogenes as a Biofilm on Various Food-Processing Surfaces

1996 ◽  
Vol 59 (8) ◽  
pp. 827-831 ◽  
Author(s):  
ISABEL C. BLACKMAN ◽  
JOSEPH F. FRANK
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Biofilm Formation ◽  
Minimal Medium ◽  
Processing Plant ◽  
Biofilm Growth ◽  
Sanitary Condition ◽  
Plant Environment ◽  
Substantial Risk

The objective of this research was to determine the ability of Listeria monocytogenes to grow as a biofilm on various food-processing surfaces including stainless steel, Teflon®, nylon, and polyester floor sealant. Each of these surfaces was able to support biofilm formation when incubation was at 21°C in Trypticase soy broth (TSB). Biofilm formation was greatest on polyester floor sealant (40% of surface area covered after 7 days of incubation) and least on nylon (3% coverage). The use of chemically defined minimal medium resulted in a lack of biofilm formation on polyester floor sealant, and reduced biofilm levels on stainless steel. Biofilm formation was reduced with incubation at 10°C, but Teflon® and stainless steel still allowed 23 to 24% coverage after incubation in TSB for 18 days. Biofilm growth of L. monocytogenes was sufficient to provide a substantial risk of this pathogen contaminating the food-processing plant environment if wet surfaces are not maintained in a sanitary condition.

scholarly journals Coselection of Cadmium and Benzalkonium Chloride Resistance in Conjugative Transfers from Nonpathogenic Listeria spp. to Other Listeriae

2012 ◽  
Vol 78 (21) ◽  
pp. 7549-7556 ◽  
Author(s):  
S. Katharios-Lanwermeyer ◽  
M. Rakic-Martinez ◽  
D. Elhanafi ◽  
S. Ratani ◽  
J. M. Tiedje ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Benzalkonium Chloride ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Processing Plant ◽  
Cadmium Resistance ◽  
Transfer Resistance ◽  
Content Type ◽  
Plant Environment ◽  
Disinfectant Resistance

ABSTRACTResistance to the quaternary ammonium disinfectant benzalkonium chloride (BC) may be an important contributor to the ability ofListeriaspp. to persist in the processing plant environment. Although a plasmid-borne disinfectant resistance cassette (bcrABC) has been identified inListeria monocytogenes, horizontal transfer of these genes has not been characterized. NonpathogenicListeriaspp. such asL. innocuaandL. welshimeriare more common thanL. monocytogenesin food processing environments and may contribute to the dissemination of disinfectant resistance genes in listeriae, includingL. monocytogenes. In this study, we investigated conjugative transfer of resistance to BC and to cadmium from nonpathogenicListeriaspp. to other nonpathogenic listeriae, as well as toL. monocytogenes. BC-resistantL. welshimeriandL. innocuaharboringbcrABC, along with the cadmium resistance determinantcadA2, were able to transfer resistance to other nonpathogenic listeriae as well as toL. monocytogenesof diverse serotypes, including strains from the 2011 cantaloupe outbreak. Transfer among nonpathogenicListeriaspp. was noticeably higher at 25°C than at 37°C, whereas acquisition of resistance byL. monocytogeneswas equally efficient at 25 and 37°C. When the nonpathogenic donors were resistant to both BC and cadmium, acquisition of cadmium resistance was an effective surrogate for transfer of resistance to BC, suggesting coselection between these resistance attributes. The results suggest that nonpathogenicListeriaspp. may behave as reservoirs for disinfectant and heavy metal resistance genes for other listeriae, including the pathogenic speciesL. monocytogenes.

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