Pathogenicity of Food and Clinical Listeria monocytogenes Isolates in a Mouse Bioassay

2003 ◽  
Vol 66 (12) ◽  
pp. 2362-2366 ◽  
Author(s):  
KAZUE TAKEUCHI ◽  
MARY ALICE SMITH ◽  
MICHAEL P. DOYLE
Keyword(s):  
Listeria Monocytogenes ◽  
Raw Milk ◽  
The United States ◽  
Clinical Samples ◽  
Mouse Bioassay ◽  
Factors Affecting ◽  
Serotype 1 ◽  
Horse Blood ◽  
Serotype 4B ◽  
Immunocompromised Mice

Serotype distributions of Listeria monocytogenes in clinical samples and foods often differ. It is unknown whether such differences reflect a variation in the virulence of strains or are due to other factors that are not directly related to the strains' ability to cause illnesses. Fifty-two food and eight clinical isolates of L. monocytogenes were obtained from France, Japan, and the United States. Their pathogenicity in nonimmunocompromised female ICR mice was determined by intraperitoneal (i.p.) injection of the mice with test strains at 108 to 109 CFU per mouse. Five mice were injected with each Listeria strain and observed for 5 days. Listeria isolates that caused at least one death in 5 days were considered pathogenic. Isolates that caused no deaths in 5 days were considered nonpathogenic. All strains except Listeria innocua and one L. monocytogenes serotype 4b strain (RM3-1) isolated from bovine raw milk were pathogenic to nonimmunocompromised mice. Three food isolates of L. monocytogenes serotype 1/2c were weakly pathogenic to nonimmunocompromised mice, killing a maximum of 50% of mice at 108 CFU. Strains with no pathogenicity or reduced pathogenicity were further tested for their pathogenicity to immunocompromised mice. Each strain was inoculated i.p. into five mice at 103 to 1010 CFU per mouse. No deaths of immunocompromised mice inoculated with 108 CFU were observed, but 20 to 40% of the mice died when inoculated with 109 CFU of L. monocytogenes RM3-1. The three L. monocytogenes serotype 1/2c isolates were also weakly pathogenic to immunocompromised mice, with two of the three isolates killing ≤60% of mice at doses of ≤108 CFU. The hemolytic activity of the three weakly pathogenic serotype 1/2c isolates was similar to that of pathogenic strains. However, the nonpathogenic strain RM3-1 was not found to be hemolytic on horse blood agar. We have identified several L. monocytogenes strains with reduced virulence levels. Further characterization of such isolates may aid in understanding factors affecting the variation in virulence among strains.

scholarly journals Heavy-Metal and Benzalkonium Chloride Resistance of Listeria monocytogenes Isolates from the Environment of Turkey-Processing Plants

2008 ◽  
Vol 74 (5) ◽  
pp. 1464-1468 ◽  
Author(s):  
S. Mullapudi ◽  
R. M. Siletzky ◽  
S. Kathariou
Keyword(s):  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Food Processing ◽  
Benzalkonium Chloride ◽  
The United States ◽  
Limited Information ◽  
Chloride Resistance ◽  
Processing Plants ◽  
Serotype 1 ◽  
Serotype 4B

ABSTRACT The resistance of Listeria monocytogenes to cadmium and arsenic has been used extensively for strain subtyping. However, limited information is available on the prevalence of such resistance among isolates from the environment of food-processing plants. In addition, it is not known whether the resistance of such isolates to heavy metals may correlate with resistance to quaternary ammonium compounds extensively used as disinfectants in the food-processing industry. In this study, we characterized 192 L. monocytogenes isolates (123 putative strains) from the environment of turkey-processing plants in the United States for resistance to cadmium and arsenic and to the quaternary ammonium disinfectant benzalkonium chloride (BC). Resistance to cadmium was significantly more prevalent among strains of serotypes 1/2a (or 3a) and 1/2b (or 3b) (83% and 74%, respectively) than among strains of the serotype 4b complex (19%). Resistance to BC was encountered among 60% and 51% of the serotype 1/2a (or 3a) and 1/2b (or 3b) strains, respectively, and among 7% of the strains of the serotype 4b complex. All BC-resistant strains were also resistant to cadmium, although the reverse was not always the case. In contrast, no correlation was found between BC resistance and resistance to arsenic, which overall was low (6%). Our findings suggest that the processing environment of turkey-processing plants may constitute a reservoir for L. monocytogenes harboring resistance to cadmium and to BC and raise the possibility of common genetic elements or mechanisms mediating resistance to quaternary ammonium disinfectants and to cadmium in L. monocytogenes.

scholarly journals Relatedness of Listeria monocytogenes Isolates Recovered from Selected Ready-To-Eat Foods and Listeriosis Patients in the United States

2005 ◽  
Vol 71 (12) ◽  
pp. 8115-8122 ◽  
Author(s):  
Stefanie Evans Gilbreth ◽  
Jeff E. Call ◽  
F. Morgan Wallace ◽  
Virginia N. Scott ◽  
Yuhuan Chen ◽  
...  
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Food Products ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
Clinical Isolates ◽  
Pulsed Field ◽  
Serotype 1 ◽  
Serotype 4B

ABSTRACT Pulsed-field gel electrophoresis and serotyping were performed for 544 isolates of Listeria monocytogenes, including 502 isolates recovered from contaminated samples from 31,705 retail ready-to-eat (RTE) food products and 42 isolates recovered from human cases of listeriosis. The isolates were from Maryland (294 isolates) and California (250 isolates) and were collected in 2000 and 2001. The isolates were placed into 16 AscI pulsogroups (level of relatedness within each group, ≥66%), 139 AscI pulsotypes (levels of relatedness, ≥25% to 100%), and eight serotypes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 4b, 4c, and 4d). The most frequently found pulsotypes belonged to either pulsogroup A (150 food isolates plus 4 clinical isolates) or pulsogroup B (104 food isolates plus 5 clinical isolates). The majority of the 502 food isolates were either serotype 1/2a (298 isolates) or serotype 1/2b (133 isolates), whereas the majority of the 42 clinical isolates were either serotype 1/2a (19 isolates) or serotype 4b (15 isolates). Additionally, 13 clinical isolates displayed pulsotypes also found in food isolates, whereas the remaining 29 clinical isolates displayed 24 unique pulsotypes. These data indicate that most (86%) of the L. monocytogenes subtypes found in the RTE foods sampled belonged to only two serotypes and that 90% of the isolates displayed 73 pulsotypes, with 107 isolates displaying pulsotype 1. These data should help define the distribution and relatedness of isolates found in RTE foods in comparison with isolates that cause listeriosis.

Psychrotrophic Growth and Thermal Inactivation of Listeria monocytogenes as a Function of Milk Composition

1986 ◽  
Vol 49 (12) ◽  
pp. 994-998 ◽  
Author(s):  
CATHERINE W. DONNELLY ◽  
ELIZABETH H. BRIGGS
Keyword(s):  
Listeria Monocytogenes ◽  
Thermal Resistance ◽  
Thermal Inactivation ◽  
Skim Milk ◽  
Raw Milk ◽  
Milk Composition ◽  
Cellular Growth ◽  
Whole Milk ◽  
Serotype 1 ◽  
Serotype 4B

Listeria monocytogenes strains 19111, 19113, 19115, F5027 and F5069 were grown in 11% nonfat milk solids, skim milk and whole milk at 4, 10, 22, and 37°C to determine the influence of temperature and milk composition on growth and thermal resistance. Milk composition affected cellular growth. The psychrotrophic growth of L. monocytogenes serotype 4b strains was enhanced in whole milk when compared to skim milk or 11% NFMS. This enhancement of psychrotrophic growth was not observed for serotype 1 or 3 strains. The stimulatory effect of whole milk on serotype 4b L. monocytogenes strains was most dramatic at 10°C where cells increased from 7.9 × 10° to 5.8 × 106 CFU/ml within 48 h. Milk composition did not affect the thermal resistance of L. monocytogenes. All strains used in this study had a D62.7°C value of 1.0 min or less, therefore, pasteurization as defined by current FDA guidelines should eliminate this organism from raw milk with a large margin of safety. Post-pasteurization contamination of dairy products with L. monocytogenes must be eliminated since the psychrotrophic nature of this organism ensures survival and proliferation during refrigerated storage.

Listeria monocytogenes in Raw Milk: Detection, Incidence, and Pathogenicity

1987 ◽  
Vol 50 (3) ◽  
pp. 188-192 ◽  
Author(s):  
J. LOVETT ◽  
D. W. FRANCIS ◽  
J. M. HUNT
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
Sampling Period ◽  
Raw Milk ◽  
The United States ◽  
Isolation Method ◽  
Listeria Species ◽  
Adult Mice ◽  
Listeria Ivanovii

To determine the incidence of Listeria monocytogenes in raw milk, an isolation method was evaluated and used to analyze milk from three areas of the United States. The incidence varied by area from 0% in California to 7% in Massachusetts, with an overall incidence of 4.2%. The highest incidence found in any area during a single sampling period was 12% in Massachusetts in March 1985. During that same sampling, the incidence for all Listeria species was 26%. Of the 27 L. monocytogenes strains isolated during the survey, 25 were pathogenic in adult mice. One of three Listeria ivanovii isolated was pathogenic. No other isolates demonstrated pathogenicity.

Gene Transcription Patterns of pH- and Salt-Stressed Listeria monocytogenes Cells in Simulated Gastric and Pancreatic Conditions

2014 ◽  
Vol 77 (2) ◽  
pp. 254-261 ◽  
Author(s):  
MARIOS MATARAGAS ◽  
ANNA GREPPI ◽  
KALLIOPI RANTSIOU ◽  
LUCA COCOLIN
Keyword(s):  
Life Cycle ◽  
Listeria Monocytogenes ◽  
Reference Strain ◽  
Expression Patterns ◽  
Wild Strain ◽  
Hostile Environment ◽  
Fermented Sausage ◽  
Laboratory Reference ◽  
Serotype 1 ◽  
Serotype 4B

A Listeria monocytogenes subgenomic array, targeting 54 genes involved in the adhesion, adaptation, intracellular life cycle, invasion, and regulation of the infection cycle was used to investigate the gene expression patterns of acid- and salt-stressed Listeria cells after exposure to conditions similar to those in gastric and pancreatic fluids. Three L. monocytogenes strains, one laboratory reference strain (EGDe) and two food isolates (wild strain 12 isolated from milk and wild strain 3 isolated from fermented sausage), were used during the studies. Differences in the expressed genes were observed between the gastric and pancreatic treatments and also between the serotypes. Increased transcripts were observed of the genes belonging to the adaptation and regulation group for serotype 4b (strain 12) and to the invasion and regulation group for serotype 1/2a (strain EGDe). Interestingly, no significantly differentially expressed genes were found for serotype 3c (strain 3) in most cases. The genes related to adaptation (serotype 1/2a) and to intracellular life cycle and invasion (serotype 4b) were down-regulated in order to cope with the hostile environment of the gastric and pancreatic fluids. These findings may provide experimental evidence for the dominance of serotypes 1/2a and 4b in clinical cases of listeriosis and for the sporadic occurrence of serotype 3c.

scholarly journals Construction, Characterization, and Use of Two Listeria monocytogenes Site-Specific Phage Integration Vectors

2002 ◽  
Vol 184 (15) ◽  
pp. 4177-4186 ◽  
Author(s):  
Peter Lauer ◽  
Man Yin Nora Chow ◽  
Martin J. Loessner ◽  
Daniel A. Portnoy ◽  
Richard Calendar
Keyword(s):  
Listeria Monocytogenes ◽  
Lethal Dose ◽  
Attachment Site ◽  
Donor Cell ◽  
Single Copy ◽  
Cell Extract ◽  
Site Specific ◽  
Specific Phage ◽  
Serotype 1 ◽  
Serotype 4B

ABSTRACT Two site-specific shuttle integration vectors were developed with two different chromosomal bacteriophage integration sites to facilitate strain construction in Listeria monocytogenes. The first vector, pPL1, utilizes the listeriophage U153 integrase and attachment site within the comK gene for chromosomal insertion. pPL1 contains a useful polylinker, can be directly conjugated from Escherichia coli into L. monocytogenes, forms stable, single-copy integrants at a frequency of ∼10−4 per donor cell, and can be used in the L. monocytogenes 1/2 and 4b serogroups. Methods for curing endogenous prophages from the comK attachment site in 10403S-derived strains were developed. pPL1 was used to introduce the hly and actA genes at comK-attBB′ in deletion strains derived from 10403S and SLCC-5764. These strains were tested for second-site complementation in hemolysin assays, plaquing assays, and cell extract motility assays. Unlike plasmid-complemented strains, integrated pPL1-complemented strains were fully virulent in the mouse 50% lethal dose assay. Additionally, the PSA phage attachment site on the L. monocytogenes chromosome was characterized, and pPL1 was modified to integrate at this site. The listeriophage PSA integrates in the 3′ end of an arginine tRNA gene. There are 17 bp of DNA identity between the bacterial and phage attachment sites. The PSA prophage DNA sequence reconstitutes a complete tRNAArg gene. The modified vector, pPL2, was integration proficient at the same frequency as pPL1 in common laboratory serotype 1/2 strains as well as serotype 4b strains.

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 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 Genome Sequence of Listeria monocytogenes Strain F4244, a 4b Serotype

2017 ◽  
Vol 5 (49) ◽  
Author(s):  
Taylor W. Bailey ◽  
Naila C. do Nascimento ◽  
Arun K. Bhunia
Keyword(s):  
Listeria Monocytogenes ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Genome Sequence ◽  
Illumina Sequencing ◽  
Foodborne Pathogen ◽  
Whole Genome ◽  
Content Type ◽  
Serotype 1 ◽  
Serotype 4B

ABSTRACT Listeria monocytogenes is an opportunistic invasive foodborne pathogen. Here, we performed whole-genome sequencing of L. monocytogenes strain F4244 (serotype 4b) using Illumina sequencing. The sequence showed 94.5% identity with strain F2365, serotype 4b, and 90.6% with EGD-e, serotype 1/2a.

Sign in / Sign up

Export Citation Format

Share Document