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PubMed2006

[A fatal case of Listeria monocytogenes sepsis and meningitis in a patient with Wegener's granulomatosis].

The bacillus Listeria monocytogenes is widely distributed in the environment. Listeria monocytogenes most often causes infection in the neonates, pregnant women, elderly and immunosuppressed persons. We report on a case of fatal sepsis and meningitis in a 59-year-old woman receiving cyclophosphamide and glucocorticoid therapy for Wegener's granulomatosis over a 10-year period. Listeriosis should be suspected in case of sepsis and/or meningitis in patients who receive immunosuppressive agents. Since meningitis due to Listeria monocytogenes is not distinguishable clinically from other types of bacterial meningitis, antibiotics against Listeria monocytogenes should be included in the initial empirical therapy of bacterial meningitis in immunosuppressed patients, antibiotics against Listeria monocytogenes should be included.

Fatal Outcome↗
PubMed1987

T cell recognition of listeriolysin O is induced during infection with Listeria monocytogenes.

During bacterial multiplication, Listeria monocytogenes (strain EGD) secretes sulfhydryl-dependent cytotoxin, termed listeriolysin O, a virulence factor presumable promoting intracellular growth of this ubiquitous pathogen. The role of this exotoxin in the process of T cell activation was studied in vivo during the course of an experimental infection in the mouse. By using highly purified listeriolysin O, it was found that infection with viable, replicative bacteria induced in vivo the emergence of T cells specifically reacting against this exotoxin, as demonstrated by eliciting the expression of delayed-type hypersensitivity to listeriolysin O in Listeria-immune mice. The kinetics of this inflammatory reaction followed the same pattern as that observed with crude Listeria antigenic preparation classically used for the detection of delayed-type hypersensitivity, with a peak of expression by day 6 and a slow decline over the next 3 wk to a residual level, indicating the presence of memory T cells reacting with the exotoxin. This result, therefore, allowed us to identify for the first time that a pure immunogenic molecule secreted by L. monocytogenes is specifically recognized by sensitized T cells induced during the course of infection by L. monocytogenes. The expression of T cell-mediated immunity to listeriolysin O was generated by very low amounts of replicative bacteria, indicating that the exotoxin released in host tissues during the process of intracellular growth is highly immunogenic. Our data favor the view that the binding of listeriolysin O to the membrane cholesterol might be a critical event potentiating the in vivo expression of delayed sensitivity against this exotoxin. Indeed, the insertion of listeriolysin O into the cell membrane induced resistance to enzymatic proteolysis and membrane-bound listeriolysin O was significantly more effective in inducing delayed inflammatory reaction in Listeria-immune mice.

Animals↗
PubMed1990

Western blot analysis of the antibody response in patients with Listeria monocytogenes meningitis and septicemia.

The antibody response in patients with Listeria monocytogenes septicemia and/or meningitis was investigated using Western blot analysis (WBA). Protein antigen preparations were produced from two strains of Listeria monocytogenes, representing serogroup 1 and 4, by sonication and differential centrifugation. IgG antibodies from 8 (50%) of 16 patients with culture verified septicemia and/or meningitis due to Listeria monocytogenes reacted with a 93 kDa antigen from serogroup 1, in contrast to IgG antibodies from only 1 (2%) of 51 controls; these controls represented 21 patients with infections caused by other bacteria and 30 apparently healthy blood donors. Furthermore, IgM antibodies from 3 (19%) of the patients with listeric infections bound to a 106 kDa protein antigen in contrast to none of the controls. In 3 (33%) of 9 patients from whom acute and convalescence serum were available, the patients responded by producing antibodies against new protein antigens. Current methods used in routine serological investigations, i.e. complement fixation and O-agglutination tests, were positive in only 4 (24%) of the 16 patients with listeriosis. The results point to the possibility of designing new immunoassays for detection of septicemia and meningitis caused by Listeria monocytogenes.

Antibodies, Bacterial↗
PubMed1976

Interaction of Listeria monocytogenes and influenza in an animal model.

This study was designed to investigate the effects of viruses in the pathogenesis of Listeria monocytogenes. The organisms used in this study were: Listeria monocytogenes Type 1 isolated from a local fatal case; Mouse adapted influenza A/PR8/34 (HONI); Streptococcus pneumoniae Group B (U.M. Med. Ctr.) and poliovirus Type 2 MEF--G3M2. Balb-C mice were inoculated intraperitoneally with one LD50 of Listeria monocytogenes. Ten days later, the survivors were challenged intransally with 10 LD50 of influenza virus and observed for 14 days. Another set of Balb-C mice was inoculated intranasally with one LD50 of influenza virus and the survivors challenged 14 days later intraperitoneally with 10 LD50 of Listeria monocytogenes. Controls consisted of similar inoculation and challenge methods in mice using Streptococcus pneumoniae and polio virus with Listeria monocytogenes and influenza virus. Cross protection was observed only between Listeria monocytogenes and influenza virus. Cellular immunity may play a role in this interaction. This findings seem to agree with reports from others who showed cross protection between Listeria monocytogenes and other intracellular bacteria and parasites.

Administration, Intranasal↗
PubMed2005

Influence of bacteriocin-like substance, generation times, and genetic profiles of Listeria innocua on the isolation of Listeria monocytogenes.

Inhibition of isolation of Listeria monocytogenes by bacteriocin-like substance (BLS)-producing Listeria innocua after enrichment culture was investigated. When 26 L. monocytogenes strains were examined in combination with eight L. innocua strains using the spot on lawn method, 52/208 (25.0%) combinations showed the growth inhibition of L. monocytogenes. When two Listeria species were cultured simultaneously in selective enrichment broth, inhibition of isolation of L. monocytogenes was observed in 12/52 of the combinations at 24h (23.1%), in 24/52 at 48h (46.2%) and in 30/52 (57.7%) after 7 days of incubation. The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the BLS-producing L. innocua or the BLS-sensitive L. monocytogenes strains. Therefore inhibition by BLS-producing L. innocua of isolation of L. monocytogenes after enrichment culture is unlikely to be dependent upon a particular genetic profile.

Bacteriocins↗
PubMed2002

Penicillin-binding proteins of listeria monocytogenes--a re-evaluation.

Intact Listeria monocytogenes cells or membranes isolated from them were treated with [3H]penicillin to allow identification of the penicillin binding proteins (PBPs) located in the cytoplasmic membrane. In the former case the PBPs were released from the cells following disruption of the cell wall murein with Listeria monocytogenes bacteriophage lysin. The procedure described by Dougherty et al. (1996) for Escherichia coli, with some modifications, was used to evaluate the M(r)s of the individual PBPs and allowed direct quantitation of their copy number.

Bacterial Proteins↗
PubMed1984

The immune response of human neonates to Listeria monocytogenes infection.

Infection with Listeria monocytogenes during pregnancy has a high fetal and neonatal mortality. In rodents, it has been shown that resistance to Listeria infection is dependent upon a T cell-mediated immune response to the bacteria. The immune humoral and cell-mediated response to L. monocytogenes was studied in seven mother infant pairs who had documented evidence of L. monocytogenes sepsis. All studies were carried out 1 year following the initial infection as part of a clinical and immunological follow-up, and compared to an appropriate control group. The microagglutination titre and opsonizing activity of mothers previously infected with Listeria was significantly greater than that of the control mothers or their infected infants. There was no difference between the babies previously infected with L. monocytogenes when compared to control infants. The in vitro lymphoblastogenic response to Listeria, staphylococci, tetanus toxoid, and phytohemagglutinin was assessed. Infected mothers had a significantly greater proliferative response in the presence of Listeria than the control mothers, while the response of the previously infected infants was not different from that of the control infants. The response to the other antigens and PHA was similar in all groups. In conclusion, infants infected with L. monocytogenes during the perinatal period demonstrated neither a specific antibody response nor exhibited a cell-mediated immune response to this bacteria. These data support the idea that perinatally-infected infants have a markedly impaired immune response to L. monocytogenes and may, thus, explain their increased susceptibility to this infection.

Antibodies, Bacterial↗
PubMed1995

Behavior of Listeria monocytogenes in Mozzarella cheese in presence of Lactococcus lactis.

The behavior of Listeria monocytogenes (Scott A) on fully processed Italian Mozzarella cheese was examined in presence and in absence of bacteriocins produced by Lactococcus lactis ssp. lactis strains (DIP 15 and DIP 16). These strains, isolated from raw milk, produced heat stable bacteriocins that were inactivated by pronase, alpha- chymotrypsin and proteinase K, but not by pepsin, trypsin and catalase. The addition of crude bacteriocins to the growing culture of Listeria monocytogenes resulted in a significant reduction in cell number at 5 degrees C, but not at 30 degrees C. Mozzarella cheese was inoculated with the Listeria culture to obtain an initial level of approximately 30 CFU/cm2 surface of Mozzarella and approximately 10(3) CFU/ml of the surrounding fluid and then packaged in bags containing the heat-treated neutralized-cultures of Lactococcus lactis ssp. lactis in skim milk (in Italy, Mozzarella is sold in small size pieces, individually packaged in bags containing some fluid). Bags were stored at 5 degrees C up to 21 days. The presence of bacteriocins resulted in apparent death of Listeria monocytogenes after 24 h storage. After 7 days of storage, a revival of Listeria monocytogenes was observed, followed by an increase in number. However, for a storage period of 2-3 weeks the number of Listeria monocytogenes remained significantly below the number observed for Mozzarella cheese packaged in absence of the heat-treated cultures of Lactococcus lactis.

Animals↗
PubMed1996

[Prevention of Listeria monocytogenes contamination on dairy farms and in the cheese industry].

Listeria monocytogenes remains a pathogen bacteria the prevention of which, in food products, stays delicate. A complete organization, from the farmer's production to the industry and the consumer is necessary to eliminate Listeria in a type of food product. Listeria monocytogenes is susceptible of contaminate raw milk. The silage may be a major source of the occurrence of Listeria monocytogenes in raw milk. In this case, the contamination sources in a dairy farm and the good hygienic practices must be well-defined. In dairy industry, the contamination must be managed by the application of a systematic and methodically system like H.A.C.C.P. (Hazard Analysis Critical Control Points). It is useful for the study of Listeria monocytogenes contamination and involve the hazard analysis of each industry plant. In fact, the raw products, food products, manufacturing process, environmental conditions, process equipment, materials and staff organizational are specific and characteristic.

Animals↗
PubMedDate not supplied

[Effect of different dairy products on the growth of Listeria monocytogenes in selective media].

We have studied the influence of the incorporation of milk cream and skim milk on the growth kinetic of Listeria monocytogenes in listeria enrichment broth with 15 mg/l or 7.5 mg/l of acriflavine. Acriflavine was responsible, at least partially, for delayed growth of Listeria monocytogenes in the enrichment broths. A longer lag phase of the growth was produced by the addition of milk cream or skim milk to the enrichment broth containing 7.5 mg/l of acriflavine. However, the maximum population obtained at 48 h did not show significant differences. In the presence of 15 mg/l of acriflavine, we observed a decrease of the viable counts during the early phase of the growth cycle, which was enhanced by the addition of milk cream or skim milk. Moreover, the maximum growth rate was reduced by the addition of skim milk and maximum population was not reached at 48 h. These results suggest the need to validate the methodology of recuperation of Listeria monocytogenes from each dairy product, since its efficiency may be affected by product composition, specially when the sample biocharge is low.

Acriflavine↗
PubMed1988

Alteration of non-specific resistance to infection with Listeria monocytogenes.

The experimental infection of murine hosts with Listeria monocytogenes is often used as a model for cell-mediated immunity. However, the natural immunity or non-specific resistance to listeriosis can be influenced by the parasite itself and also by a wide array of endogenous and exogenous host factors. The most important host factor in inbred mouse strains is their genetically determined susceptibility or resistance to Listeria monocytogenes. Secondly, the age of the mice is crucial for the outcome of infection. Resistance is only slowly developed by newborn mice, while aged mice possess an increased non-specific resistance as compared to young adult animals. Resistance is further influenced by the nutritional status, by pregnancy or by a simultaneous second antigenic stimulation. Regarding exogenous factors, macrophage blocking agents can totally abolish the resistance to listeriosis, while a lot of immunomodulating agents, such as BCG, killed Bordetella pertussis or Propionibacterium acnes organisms, lipopolysaccharides, suramin etc., can either increase or decrease the resistance. The mononuclear phagocyte system seems to be the main target of all these immunomodifiers. The timing between listeria infection and application of the immunomodulator determines the effect on non-specific resistance. A simultaneous injection of parasite and immunomodulator results in a decrease of resistance, while the application of immunoadjuvants several days before infection can dramatically increase the resistance to listeriosis. The delicate equilibrium of the mononuclear phagocyte system must therefore be taken into account, when infection with Listeria monocytogenes is used to test for immune-modifying agents, which are intended for use in humans or animals.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Spreading of Listeria monocytogenes in cheese dairy products].

The increasingly more frequent occurrences of epidemic nidus of Listeria monocytogenes induced the E.E.C. Health Organisation to research into the diffusion of such microorganism. During the first six months of 1988 the "Istituto Superiore di Sanità" began a research into the presence of Listeria monocytogenes in milk and dairy products. The biological section of the "Laboratorio di Sanità Pubblica" of Grugliasco (Torino) participated in this study and in this work methods and results are reported. Changing the F.D.A. methods, incubation time was reduced. The percentage of positive samples was 4.6%, especially in dairy products with cheese mould. These results confirm an environmental diffusion of Listeria monocytogenes, nevertheless non illness caused by Listeria monocytogenes was recorded in the population who ate these products. Therefore the problem of Listeria monocytogenes pathogenicity and its diffusion by food remains to be clarified.

Cheese↗
PubMed1994

Phosphatidylinositol-specific phospholipase C from Listeria monocytogenes contributes to intracellular survival and growth of Listeria innocua.

Listeria monocytogenes is a facultative intracellular organism that is capable of replicating within macrophage and macrophage-like cells. The species secretes a phosphatidylinositol-specific phospholipase C (PI-PLC) encoded by the plcA gene. A plcA gene from L. monocytogenes was cloned downstream of a gram-positive promoter in the plasmid pWS2-2. To determine what effect plcA would have on intracellular survival when introduced into Listeria innocua, a species that does not growth intracellularly or contain plcA, transformation with the recombinant pWS2-2 plasmid was performed. Phospholipase C activity in Listeria innocua/pWS2-2 was confirmed on a brain heart infusion-phosphatidylinositol agar plate, whereas wild-type L. innocua did not produce PI-PLC activity. Intracellular growth of L. innocua/pWS2-2 was subsequently measured in the macrophage-like cell line J774 by Giemsa staining and viable count determinations at specific time points following infection. The J774 cells infected with wild-type L. innocua showed a falling viable count through 8 h postinfection. Although J774 cells infected with L. innocua/pWS2-2 also initially displayed reduced viable counts, the viable count rose after 6 h postinfection and increased further at 8 h postinfection before a subsequent decline again at 16 h postinfection. Giemsa staining revealed fewer than 6 bacteria in individual macrophage cells at 2 h postinfection, and yet approximately 15% of the J774 cells had 6 to 12 bacteria localized to one area of the macrophage cell after 6 h; moreover, electron micrographs showed that the L. innocua/pWS2-2 cells were replicating inside the phagosome of the host cell. Furthermore, Thoria Sol labeling demonstrated that lysosomes had fused with these phagosomes, and acridine orange staining revealed that the compartments were acidified. These results demonstrate that L. innocua cells transformed with the plasmid-borne plcA gene, and expressing functional PI-PLC, are able to grow intracellularly in what appear to be phagolysosomes, although between 3 and 6 h is needed for this to manifest itself. Intracellular growth specifically in L. innocua may be a secondary function associated with the plcA gene product. The addition of this one gene, plcA, to a species of Listeria that in the wild-type state does not replicate intracellularly apparently can now allow some of the bacteria to transiently multiply inside the phagosomes of host macrophage cells.

Amino Acid Sequence↗
PubMed1993

Effect of Legionella pneumophila sonicate on killing of Listeria monocytogenes by human polymorphonuclear neutrophils and monocytes.

Legionella pneumophila shares with other intracellular pathogens the ability to resist intracellular killing within phagocytes. An increasing number of cellular components of L. pneumophila are proposed as pathogenic factors of the organism. At the site of infection, the phagocytic cells will be exposed to bacterial components, either expressed on the surface of the organisms or released in the environment upon cell lysis. In this study, we have investigated the effect of water-soluble bacterial components present in L. pneumophila sonicate on the phagocytosis and bactericidal activity of human polymorphonuclear neutrophils and monocytes. Preincubation of neutrophils with L. pneumophila sonicate did not affect phagocytosis of L. monocytogenes, whereas Listeria killing was significantly inhibited at sonicate concentrations of 1 and 2 mg/ml. The phenol phase of a phenol-water extraction, containing most of the lipopolysaccharide (LPS), had no inhibitory effect on the listericidal activity of neutrophils. Killing of Listeria by monocytes was inhibited in a similar manner. The inhibitory activity was mainly recovered in the sonicate fraction above 100 kDa, suggesting that components organized in larger molecular complexes are most likely to represent the inhibitory factors. The inhibitory activity of L. pneumophila sonic extract appears to be related to inhibition of killing mechanisms since uptake of Listeria was not affected by the sonicate. Our observations indicate that as Legionella infection progresses, bacterial components liberated by cell lysis could exert a detrimental effect on the antimicrobial function of phagocytes, stressing the importance of early treatment of Legionnaires' disease to reduce bacterial numbers in the infected tissues.

Blood Bactericidal Activity↗
PubMed2003

Incidence of fecal carriage of Listeria monocytogenes in three healthy volunteers: a one-year prospective stool survey.

The aim of this study was to establish the incidence of fecal carriage of Listeria monocytogenes in healthy adults. A total of 868 stool specimens from three healthy volunteers (1 male and 2 females; ages 44, 39, and 60 years) were collected between 1 October 2000 and 30 September 2001. Culture was performed using Fraser broth and Palcam selective agar plates. Polymerase chain reaction (PCR) was performed using Probelia Listeria monocytogenes (BioRad, France). Overall, Listeria monocytogenes was detected in 31 of the 868 (3.57%) stool specimens using PCR. Sixteen of the 31 positive results were single events, i.e., samples collected from the same patient the day before and the day after the positive result were both negative. Positive results on two consecutive days were found four times, on three consecutive days one time, and on four consecutive days one time. Listeria monocytogenes was cultured from 10 of 868 (1.15%) stool specimens. These culture-positive samples, all positive by PCR as well, accounted for five independent episodes. Using automated ribotyping on up to 40 single colonies per stool specimen, 9 of 10 culture-positive samples yielded more than one strain. There was no obvious seasonal clustering of positive results. None of the documented episodes of Listeria monocytogenes carriage, all of which involved serotypes 1/2a and 1/2b, coincided with overt illness. The results of PCR indicate an incidence of five to nine exposures to Listeria monocytogenes per person per year. On average, the incidence of culture-confirmed fecal carriage in healthy adults is two episodes of Listeria monocytogenes carriage per person per year. Fecal shedding was of short duration (maximum 4 days), which argues against the appropriateness of routine stool screening in dairy workers as a tool for prevention of listeriosis.

Adult↗
PubMed2006

Identification, subtyping and virulence determination of Listeria monocytogenes, an important foodborne pathogen.

Listeria monocytogenes is an opportunistic intracellular pathogen that has become an important cause of human foodborne infections worldwide. Given its close relationship to other Listeria species and its tendency to produce non-specific clinical symptoms, the availability of rapid, sensitive and specific diagnostic tests for the differentiation of L. monocytogenes from other Listeria species is helpful for selecting appropriate treatment regimens. In addition, with L. monocytogenes comprising a diversity of strains of varying pathogenicity, the ability to precisely track the strains involved in listeriosis outbreaks and speedily determine their pathogenic potential is critical for the control and prevention of further occurrences of this deadly disease. Extensive research in recent decades has revealed significant insights regarding the molecular mechanisms of L. monocytogenes infection. This in turn has facilitated the development of laboratory procedures for enhanced detection and identification of L. monocytogenes, and has also contributed to the implementation of improved control and prevention strategies against listeriosis. The purpose of this review is to summarize recent progress in the species-specific identification, subtyping and virulence determination of L. monocytogenes strains, and to discuss future research needs pertaining to these important areas of listeriosis.

Animals↗
PubMed1992

Biliary excretion as possible origin of Listeria monocytogenes in fecal carriers.

The presence of Listeria monocytogenes in feces of animals has been related with ingestion of contaminated foods. In the study reported here, healthy mice inoculated SC with L monocytogenes excreted the organism in their feces, regardless of whether they developed clinical signs of infection. Listeria monocytogenes was isolated simultaneously from liver, feces, and bile of inoculated mice, which strongly suggested that the microorganism reached the gastrointestinal tract by biliary excretion.

Animals↗