scholarly journals Competitive Fitness of Listeria monocytogenes Serotype 1/2a and 4b Strains in Mixed Cultures with and without Food in the U.S. Food and Drug Administration Enrichment Protocol

2006 ◽  
Vol 72 (1) ◽  
pp. 776-783 ◽  
Author(s):  
Lisa Gorski ◽  
Denise Flaherty ◽  
Robert E. Mandrell
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
Mixed Cultures ◽  
Genetic Lineage ◽  
Processing Plants ◽  
Serotype 1 ◽  
Enrichment Protocol ◽  
Serotype 4B ◽  
The U.S

ABSTRACT Thirteen different serotypes of the food-borne pathogen Listeria monocytogenes have been described. Serotype 4b strains are most often associated with illness, and serotype 1/2a strains are most often isolated from foods and processing plants. Different abilities to respond to stresses have been described for serotype 4b and 1/2a strains. One of the common enrichment protocols used to test foods for the presence L. monocytogenes is described in the U.S. Food and Drug Administration (FDA) Bacterial Analytical Manual (BAM). We compared three strains of L. monocytogenes serotype 4b and five strains of serotype 1/2a in direct competition with each other in two-strain mixed cultures by using the FDA BAM enrichment protocol, which includes both enrichment broth and selective agar, with and without added food to mimic the conditions that occur during attempts to isolate Listeria species from contaminated foods. Using a colony immunoblot procedure and analyzing over 112,000 colonies, we observed differences in strain fitness, but these differences were not attributable to serotype or genetic lineage.

Formation of Biofilm at Different Nutrient Levels by Various Genotypes of Listeria monocytogenes

2006 ◽  
Vol 69 (4) ◽  
pp. 826-834 ◽  
Author(s):  
JAMES P. FOLSOM ◽  
GREGORY R. SIRAGUSA ◽  
JOSEPH F. FRANK
Keyword(s):  
Listeria Monocytogenes ◽  
Food Processing ◽  
Hoechst 33258 ◽  
Genetic Subtype ◽  
Processing Plants ◽  
Serotype 1 ◽  
Serotype 4B ◽  
Different Strains ◽  
Element Sequence ◽  
Range Test

Strains of Listeria monocytogenes differ in their ability to form biofilms. The objectives of this study were to determine whether genetically related strains have similar biofilm-forming capacities and what effect nutrient concentration has on the ability of different strains to produce biofilms. Biofilms of 30 strains of L. monocytogenes, obtained from a variety of sources were grown on stainless steel in tryptic soy broth (TSB) or in a 1:10 dilution of TSB (DTSB) for 24 h at 32°C. The amount of biofilm formed was determined with image analysis after cells were stained with bisBenzimide H 33258 (Hoechst 33258). The strains were genetically subtyped by repetitive element sequence–based PCR (rep-PCR) with the primer set rep-PRODt and rep-PROG5. Data were analyzed with an analysis of variance and Duncan's multiple range test. Eleven strains produced the same amount of biofilm in both media. Fourteen strains produced more biofilm in TSB than in DTSB. Five strains produced more biofilm in DTSB than in TSB. Serotype 4b strains produced more biofilm in TSB than did serotype 1/2a strains, whereas serotype 1/2a strains produced more biofilm in DTSB than did serotype 4b strains. Growth in DTSB resulted in decreased biofilm accumulation for serotype 4b strains. There was no correlation between genetic subtype and the amount of biofilm accumulation. These results indicate that strains of serotype 1/2a and serotype 4b differ in the regulation of their biofilm phenotype. The poor biofilm accumulation of serotype 4b isolates when grown in DTSB could be a factor in the predominance of serogroup 1/2 strains in food processing plants, where nutrients may be limited.

Recovery of Heat-Stressed Listeria monocytogenes from Experimentally and Naturally Contaminated Shrimp

1990 ◽  
Vol 53 (1) ◽  
pp. 22-25 ◽  
Author(s):  
SUSAN A. McCARTHY ◽  
MILES L. MOTES ◽  
R. MERRILL McPHEARSON
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
New Method ◽  
Department Of Agriculture ◽  
The U.S ◽  
Thermally Stressed

A method was developed to enhance recovery of thermally stressed Listeria monocytogenes from internally contaminated shrimp. Shrimp tail meat was inoculated with 105 L. monocytogenes cells/g and boiled for 1–5 min. Thermally stressed L. monocytogenes cells were recovered following cold enrichment for 3 d without broth. Methods of the Food and Drug Administration and the U.S. Department of Agriculture for isolating L. monocytogenes permitted recovery of the organism from shrimp boiled for 1 min: however, with the new method, L. monocytogenes cells were recovered from shrimp boiled up to 5 min. No Listeria spp. were recovered from naturally contaminated, frozen, imported shrimp after 1 min of boiling.

Characterization of Listeria monocytogenes Recovered from Imported Cheese Contributed to the National PulseNet Database by the U.S. Food and Drug Administration from 2001 to 2008

2010 ◽  
Vol 73 (8) ◽  
pp. 1511-1514 ◽  
Author(s):  
BABGALEH B. TIMBO ◽  
CHRISTINE KEYS ◽  
KARL KLONTZ
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Genetic Relatedness ◽  
Tracking System ◽  
Food And Drug Administration ◽  
The United States ◽  
Surveillance Network ◽  
Imported Foods ◽  
The U.S

Imported foods must meet the same U.S. Food and Drug Administration (FDA) standards as domestic foods. The FDA determines whether an imported food is in compliance with the Federal Food, Drug, and Cosmetic Act. Pursuant to its regulatory activities, the FDA conducts compliance surveillance on imported foods offered for entry into the U.S. commerce. The National PulseNet Database is the molecular surveillance network for foodborne infections and is widely used to provide real-time subtyping support to epidemiologic investigations of foodborne diseases. FDA laboratories use pulsed-field gel electrophoresis to subtype foodborne pathogens recovered from imported foods and submit the molecular patterns to the National PulseNet Database at the Centers for Disease Control and Prevention. There were 60 isolates of Listeria monocytogenes in the FDA Field Accomplishment and Compliance Tracking System from 2001 to 2008 due to cheese imported from the following countries: Mexico (n = 21 isolates), Italy (19), Israel (9), Portugal (5), Colombia (3), Greece (2), and Spain (1). We observed genetic diversity of L. monocytogenes isolates and genetic relatedness among strains recovered from imported cheese products coming to the United States from different countries. Consistent characterization of L. monocytogenes isolates recovered from imported cheeses, accompanied by epidemiologic investigations to ascertain human illness associated with these strains, could be helpful in the control of listeriosis acquired from imported cheeses.

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.

The Incidence of Listeria Species in Frozen Seafood Products

1988 ◽  
Vol 51 (8) ◽  
pp. 655-657 ◽  
Author(s):  
STEPHEN D. WEAGANT ◽  
PATRICIA N. SADO ◽  
KAREN G. COLBURN ◽  
JAMES D. TORKELSON ◽  
FRED A. STANLEY ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
Isolation Method ◽  
Listeria Species ◽  
The World ◽  
Seafood Products ◽  
Raw Shrimp ◽  
The U.S

Samples of frozen seafood products from several countries were tested for the presence of Listeria monocytogenes and other Listeria species using the U.S. Food and Drug Administration (FDA) Listeria isolation method. Of 57 samples tested, 35 contained Listeria species and 15 of 57 samples contained L. monocytogenes. Samples found positive included raw shrimp, cooked and peeled shrimp, cooked crabmeat, raw lobster tails, langostinos, scallops, squid and surimi-based imitation seafoods. Positive samples were obtained from nine different countries around the world.

HIV

2018 ◽  
Author(s):  
Joshua M. Sharfstein
Keyword(s):  
Public Health ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
Research Process ◽  
National Institutes Of Health ◽  
Health Agencies ◽  
Act Up ◽  
The U.S

The emergence of AIDS in the early 1980s caused a profound crisis for federal health agencies, particularly the National Institutes of Health (NIH) and the U.S. Food and Drug Administration (FDA). Activists in ACT UP, charging that these agencies were failing patients with AIDS, initiated a series of escalating protests. NIH officials, led by Dr. Anthony Fauci, began to talk with the advocates and make major changes in the research process. However, over at the FDA, a protest involving the arrest of hundreds of AIDS activists undermined the agency’s public health image. Eventually, under a new commissioner, the FDA earned back the trust of activists.

Listeria in Seafoods: A Review

1992 ◽  
Vol 55 (12) ◽  
pp. 1009-1015 ◽  
Author(s):  
RONDA M. DILLON ◽  
THAKOR R. PATEL
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Resistance ◽  
Drug Administration ◽  
Food And Drug Administration ◽  
Environmental Contaminant ◽  
Fresh Waters ◽  
Smoked Fish ◽  
Seafood Products ◽  
Crab Meat

Listeria is an environmental contaminant which has been isolated from marine and fresh waters, as well as various seafoods. Furthermore, Listeria, including Listeria monocytogenes, has been isolated from processed seafood products such as smoked fish, cooked and frozen seafoods, marinated fish, surimi products, etc. The pathogen, L. monocytogenes, does have a certain degree of heat resistance. It was found to survive in internally infected shrimp after boiled for up to 5 min. However, the commercial pasteurization process for crab meat was found to be sufficient to inactivate Listeria. The current recovery methodology for L. monocytogenes from seafoods is the Food and Drug Administration Listeria protocol.

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