| the occurrence of listeria species in milk and dairy products: a national survey in england and wales. | a total of 4172 samples of milk, cheese and other dairy products were examined over a 1-year period for the presence of listeria species. strains of listeria were found most frequently in soft, ripened cows milk cheese; 63 out of 769 (8.2%) samples contained listeria monocytogenes, 25 samples contained species other than l. monocytogenes, and 18 samples contained both l. monocytogenes and other listeria spp. eleven samples of pasteurized cows milk (1.1%) from four dairies contained l. monocytoge ... | 1991 | 1904761 |
| effect of temperature history on the growth of listeria monocytogenes scott a at refrigeration temperatures. | the effect of pre-inoculation temperature on the subsequent growth of listeria monocytogenes scott a at 5 degrees c was examined in microbiological medium, uht milk, canned dog food, and raw ground beef (untreated and irradiation-sterilized). in microbiological medium, the duration of the lag phase was decreased when aerobic and anaerobic cultures were initially grown at less than or equal to 28 and less than or equal to 13 degrees c, respectively. subsequent exponential growth rates and maximum ... | 1991 | 1904762 |
| survey of the incidence of listeria monocytogenes and other listeria spp. in experimentally irradiated and in matched unirradiated raw chickens. | listeria spp. were sought in 32 chickens experimentally irradiated (2.5 kgy) and in 25 matched unirradiated chickens. using the modified food and drug administration method only three of the chickens were positive for l. monocytogenes. using the more sensitive cold enrichment method 30 were found positive. the proportion of carcasses contaminated with l. monocytogenes was lower in the irradiated birds than in the unirradiated birds. the results also indicated that the numbers of l. monocytogenes ... | 1991 | 1904763 |
| incidence of aeromonas and listeria spp. in red meat and milk samples in brisbane, australia. | a total of 150 samples, 50 each of beef, lamb and pork from 10 local retail stores in brisbane metropolitan area as well as 150 raw bovine bulk milk tank samples obtained from queensland united foods (quf), were examined for the presence of aeromonas and listeria spp. over a period of 1 year. different sets of enrichment and plating media were used to recover the organisms with subsequent identification using conventional biochemical and serotyping techniques. a total of 509 isolates consisting ... | 1991 | 1904764 |
| comparison of a cold enrichment and the fda method for isolating listeria monocytogenes and other listeria spp. from ready-to-eat food on retail sale in the u.k. | a cold enrichment and the modified fda selective enrichment method were compared for their ability to detect listeria monocytogenes and other listeria species from various ready-to-eat foods on sale in the uk. of 57 food samples examined using cold enrichment, five yielded l. monocytogenes, and two l. innocua. the fda enrichment method yielded three samples positive for l. monocytogenes only. foods examined included soft cheeses, fermented meat sausages, pates and salads. | 1991 | 1904765 |
| purification and characterization of an extracellular 29-kilodalton phospholipase c from listeria monocytogenes. | we purified and characterized an extracellular phospholipase produced by listeria monocytogenes. this enzyme was separated as a homogeneous protein of 29 kda by chromatography on deae-52 cellulose and bio-gel p100 columns. it is a zinc-dependent phospholipase c (plc) that is mainly active at ph 6 to 7 and expresses lecithinase activity and a weaker sphingomyelinase activity. the exoenzyme also hydrolyzed phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin but not ... | 1991 | 1904842 |
| the survival of listeria monocytogenes in cottage cheese. | because of the difficulty of ensuring that cottage cheese is produced in conditions that prevent contamination with listeria monocytogenes, the ability of this bacterium to survive in cottage cheese from three sources was investigated (a) during shelf-life at chill temperature and (b) in conditions of temperature abuse. three batches of creamed cottage cheese, from three sources, received within 24 h of production, were inoculated with l. monocytogenes strain f6861 and stored at 4, 8 or 12 degre ... | 1991 | 1905281 |
| cytopathogenic effects in enterocytelike caco-2 cells differentiate virulent from avirulent listeria strains. | we have developed a simple test that differentiates between virulent and avirulent listeria species as defined by the mouse 50% lethal doses (ld50s). the assay is based on trypan blue-revealed cytopathogenic effects that are produced during the infection of the human enterocytelike cell line caco-2. these effects were elicited only by listeria strains that had an intraperitoneal mouse ld50 less than 10(8) and were not produced by nonhemolytic, avirulent strains of listeria monocytogenes generate ... | 1991 | 1905323 |
| stable listeria monocytogenes live vaccine candidate strains with graded attenuation on the mouse model. | metabolic drift (antibiotics resistance) mutations were used to construct stable two (and three) marker vaccine candidate strains of the predominant listeria monocytogenes serotypes 1/2a and 4b by stepwise selection. derived from wild-type strains, spontaneous chromosomal streptomycin-resistant clones with their i.p. ld50 elevated from less than or equal to 10(5.0) c.f.u. to approximately 10(6.1) c.f.u. were used in the second step to isolate the rifampicin-resistant mutants with i.p. ld50 value ... | 1991 | 1905446 |
| restriction enzyme analysis of listeria monocytogenes strains associated with food-borne epidemics. | listeria monocytogenes (serotype 4b) has caused four major food-borne epidemics in north america. in this study, l. monocytogenes isolates from the nova scotia (canada), boston (mass.), and los angeles (calif.) outbreaks were examined by restriction enzyme analysis with the endonuclease hhai. human isolates (n = 32) from the 1981 canadian outbreak were compared with a strain recovered from coleslaw, which was epidemiologically incriminated as the vehicle of infection. after hhai digestion, 29 of ... | 1991 | 1905523 |
| identification of cytokines which enhance (csf-1, il-3) or restrict (ifn-gamma) growth of intramacrophage listeria monocytogenes. | murine peritoneal macrophages were isolated by adherence and their listericidal activity assessed in the presence or absence of selected cytokines. untreated macrophages were not highly listericidal, showing moderate killing in the first 2 h after infection, and allowed progressive microbial growth thereafter (up to 9 h). pre-treatment of cells with 10 to 100 u/ml of ifn-gamma allowed macrophages to develop sustained listericidal activity for the 9-h observation period, with a 2-log reduction of ... | 1991 | 1905680 |
| bacterial entry into eukaryotic cells. | | 1991 | 1905978 |
| entry of l. monocytogenes into cells is mediated by internalin, a repeat protein reminiscent of surface antigens from gram-positive cocci. | we report the identification of a previously unknown gene, inla, which is necessary for the gram-positive intracellular pathogen listeria monocytogenes to invade cultured epithelial cells. the inla region was localized by transposon mutagenesis, cloned, and sequenced. inla was introduced into listeria innocua and shown to confer on this normally noninvasive species the ability to enter cells. sequencing of inla predicts an 80 kd protein, internalin. two-thirds of internalin is made up of two reg ... | 1991 | 1905979 |
| biological functions of the water-insoluble fraction of mouse seminal vesicle fluid. i. suppression of the blastogenic response of lymphocytes. | the effects of the water-insoluble fraction of mouse seminal vesicle fluid (wif-svf) on lymphocytes was investigated to clarify its role in reproductive immunity. wif-svf inhibited the blastogenic response of t-cells to concanavalin-a (con-a), but it did not inhibit the blastogenic response of b-cells to lipopolysaccharide (lps). pretreatment of splenocytes with wif-svf did not suppress the blastogenic response of splenocytes to con-a when treated cells were washed prior to culture. wif-svf did ... | 1991 | 1906049 |
| catalase-negative listeria monocytogenes causing meningitis in an adult. clinical and laboratory features. | a 63-year-old previously healthy woman presented with acute meningitis. cultures of the cerebrospinal fluid yielded a serotype 1/2a isolate of listeria monocytogenes that was biochemically typical in all respects, other than the reproducible lack of catalase production. during therapy, the patient developed oculomotor dysfunction that was attributed to an abscess in the internal capsule. this case report documents the existence of catalase-negative l. monocytogenes indicating that catalase produ ... | 1991 | 1906240 |
| epidemiology of human listeriosis. | during the 1980s, investigation of several large epidemics of listeriosis confirmed that transmission of l. monocytogenes in food causes human disease. progress in laboratory detection and subtyping of the organism has enhanced our ability to compare human and environmental isolates of l. monocytogenes. transmission by foodborne organisms is now recognized as causing both epidemic and sporadic listeriosis. continued study of dietary risk factors associated with listeriosis is needed in order to ... | 1991 | 1906370 |
| antimicrobial activity of microgard against food spoilage and pathogenic microorganisms. | microgard, a commercially available fermented milk product containing antimicrobial metabolites, was a potent inhibitor for gram-negative bacteria such as pseudomonas, salmonella, and yersinia when 1% concentration was incorporated into agar media. gram-positive bacillus cereus, staphylococcus aureus, and listeria monocytogenes were insensitive to microgard. kluyveromyces marxianus, an unidentified black yeast, and penicillium expansum were partially suppressed, whereas aspergillus niger and a y ... | 1991 | 1906486 |
| enteral feeding and infection in the immunocompromised patient. | evidence is accumulating that immunocompromised individuals are at an increased risk of infection from foodborne pathogens including campylobacter jejuni, listeria monocytogenes, salmonella spp. normal bacterial flora and contaminants of foods and enteral feeds can also result in nosocomial infection in susceptible individuals. safe food handling, low-microbial diets, and measures to reduce bacterial contamination of enteral foods can reduce exposure to potential pathogens in the food supply. | 1991 | 1906573 |
| behavior of listeria monocytogenes inoculated into raw tomatoes and processed tomato products. | rates of death and growth of listeria monocytogenes inoculated onto raw whole and into chopped tomatoes stored at 10 and 21 degrees c were not influenced by prior treatment of tomatoes with chlorine or packaging under an atmosphere of 3% o2 and 97% n2. growth of the pathogen occurred in whole tomatoes held at 21 degrees c but not at 10 degrees c, while death occurred in chopped tomatoes stored at these temperatures. likewise, growth patterns of mesophilic aerobic microorganisms, psychrotrophic m ... | 1991 | 1906697 |
| behavior of listeria monocytogenes in wiener exudates in the presence of pediococcus acidilactici h or pediocin ach during storage at 4 or 25 degrees c. | exudative fluids were collected from packages of five brands of all-beef wieners and inoculated to contain 10(4) to 10(5) cfu of a three-strain (scott a, v7, and 101m) mixture of listeria monocytogenes per ml. listeriae were inactivated (decrease of 0.61 to 3.8 log10 cfu/ml) in all five exudates held at 4 degrees c for 29 days. l. monocytogenes grew (increase of 1.7 to 3.6 log10 cfu/ml) in two of five exudates held at 25 degrees c for 6 days. exudate was inoculated with a derivative of pediococc ... | 1991 | 1906699 |
| behavior of listeria monocytogenes during fabrication and storage of experimentally contaminated smoked salmon. | experiments were carried out to examine the behavior of listeria monocytogenes in the course of fabrication and storage of smoked salmon. in three trials, raw salmon fillets were surface inoculated with l. monocytogenes, marinated, smoked at 26 to 30 degrees c, and stored at 4 or 10 degrees c for up to 30 days. at different times during the fabrication and storage, samples were taken and, by means of the three-tube most probable number (mpn) method, quantitatively analyzed for the concentration ... | 1991 | 1906700 |
| the type strain(s) of listeria monocytogenes: a source of continuing difficulties. | the type strain of listeria monocytogenes differs from wild-type l. monocytogenes strains in more characteristics than just the previously reported deficiency in hemolytic activity and virulence in the murine infection model. the type strain from the american type culture collection (strain atcc 15313) produces lecithinase, is hemolytic on rabbit (but not sheep) blood agar, lacks motility, and shows limited cytopathogenic effects on caco-2 monolayers, whereas the type strain from the special lis ... | 1991 | 1906732 |
| [listeriosis in malignant diseases]. | listeriosis occurred in two patients, a 46-year-old woman and a 41-year-old man, in the course of an underlying malignant disease. the woman had a metastasizing pancreatic apudoma, requiring partial pancreas resection with splenectomy. after the end of cytostatic treatment she developed headaches and fever up to 40 degrees c. listeria monocytogenes was demonstrated in the blood and cerebrospinal fluid. she went into coma on the day after hospital admission and, despite antibiotic administration, ... | 1991 | 1906799 |
| roles of complement and complement receptor type 3 in phagocytosis of listeria monocytogenes by inflammatory mouse peritoneal macrophages. | listeria monocytogenes is a facultative intracellular bacterium that is phagocytosed by and can proliferate within cells of the mononuclear phagocyte system. however, the receptors used by macrophages to internalize this organism have not been identified. in the experiments described here, the contributions of serum complement component c3 and macrophage complement receptor type 3 (cr3) to opsonization and phagocytosis of l. monocytogenes by mouse inflammatory peritoneal macrophages were studied ... | 1991 | 1906842 |
| expression of the iap gene coding for protein p60 of listeria monocytogenes is controlled on the posttranscriptional level. | expression of the iap gene of listeria monocytogenes encoding a major extracellular protein (p60) was analyzed. different start sites for transcription of the iap gene were identified by primer extension analysis in l. monocytogenes and in a recombinant escherichia coli clone. the mutant riii of l. monocytogenes represents a member of the frequently occurring l. monocytogenes r mutants, which form cell chains and produce greatly reduced amounts of p60. however, the concentrations of iap-specific ... | 1991 | 1906869 |
| role of transferrin, transferrin receptors, and iron in macrophage listericidal activity. | it is not yet known what properties distinguish macrophages which can kill facultative intracellular bacteria, such as listeria monocytogenes, from those which cannot. listeria is an organism which requires iron for growth, yet macrophage listericidal mechanisms are also likely to be iron dependent. we show here that resident peritoneal macrophages and thioglycollate-elicited macrophages cannot kill listeria, but proteose peptone-elicited and fcs-elicited macrophages can. all these cell populati ... | 1991 | 1906922 |
| injury and death of frozen listeria monocytogenes as affected by glycerol and milk components. | a cell suspension of listeria monocytogenes strain scott a in phosphate buffer solution alone or with added glycerol, milk fat, lactose, or casein was frozen and stored at -18 degrees c. at suitable intervals, samples of cell suspensions were thawed at 35 degrees c and plated on suitable media to distinguish between surviving injured and noninjured cells of l. monocytogenes. glycerol (2 or 4%) protected l. monocytogenes from death and injury during frozen storage for up to 6 mo; however, when 2% ... | 1991 | 1907301 |
| strains and suspending menstrua as factors affecting death and injury of listeria monocytogenes during freezing and frozen storage. | cell suspensions of listeria monocytogenes strains v7, california, and ohio in phosphate buffer solution, tryptose broth, or milk were frozen and stored at -18 degrees c. at appropriate intervals during storage, a sample was thawed at 35 degrees c and surface-plated on suitable media to allow colony formation by noninjured or noninjured plus injured cells. degrees of death and injury were calculated from the data. cells of l. monocytogenes were more resistant to death and injury when they were s ... | 1991 | 1907302 |
| antibacterial activity of lactobacillus sake isolated from dry fermented sausages. | lactic acid bacteria isolated from spanish dry fermented sausages were screened for antagonistic activities under conditions that eliminated the effects of low ph and hydrogen peroxide. from 720 isolates tested 119 were inhibitory to lactobacillus fermentum cect285. the isolates showing the largest inhibitory activity exhibited an antagonistic effect against several other lactobacilli and the selected foodborne pathogens staphylococcus aureus and listeria monocytogenes. comparison of the antimic ... | 1991 | 1907472 |
| adaptation of listeria in liquid egg containing sucrose resulting in survival and outgrowth. | survival of listeria species was tested in liquid egg products such as albumen, yolk, whole egg and whole egg containing 25% sucrose. at an incubation temperature of 4 degrees c listeria survived in all products, and even increased slightly in yolk, whole egg and whole egg containing 25% sucrose. however, at 20-22 degrees c, in whole egg containing sucrose, a rapid an dramatic decrease in numbers of listeria was observed. following this initial decrease, an increase in the numbers of listeria wa ... | 1991 | 1907474 |
| the effect of pediococcus damnosus and pediococcus pentosaceus on the growth of pathogens in minced meat. | the antibacterial effects of one strain of pediococcus damnosus and two strains of pediococcus pentosacaeus against clostridium perfringens, listeria monocytogenes, salmonella infantis and yersinia enterocolitica were investigated. growth inhibition studies were conducted in juice from minced meat incubated at +6 degrees c and +15 degrees c for various periods after the inoculation with pediococci. inhibitory effects were seen for all bacteria tested. | 1991 | 1907475 |
| listeria. | | 1991 | 1907626 |
| rapid confirmation of listeria monocytogenes isolated from foods by a colony blot assay using a digoxigenin-labeled synthetic oligonucleotide probe. | an oligodeoxyribonucleotide probe based on the sequence of a 321-bp internal fragment of the msp gene encoding a major secreted polypeptide of listeria monocytogenes was labeled with digoxigenin by using terminal deoxynucleotidyl transferase. the specificity of the digoxigenin-labeled probe was determined by dot blot assays. the probe reacted with all strains of l. monocytogenes tested (12 of 12 strains representing five serotypes). the probe did not react with any other listeria species or with ... | 1991 | 1908203 |
| typing of human, animal, food, and environmental isolates of listeria monocytogenes by multilocus enzyme electrophoresis. | in order to elucidate some aspects of the epidemiology of listeriosis in switzerland, 181 strains of listeria monocytogenes isolated from humans, animals, food, and the environment have been analyzed by multilocus enzyme electrophoresis at 21 enzyme loci. the clone responsible for several recent food-borne outbreaks in switzerland and in north america (marked by electrophoretic type 1 and serovar 4b) has been found frequently among strains isolated from animals. thus, animals may represent a maj ... | 1991 | 1908204 |
| bioluminescence assay for estimating the hydrophobic properties of bacteria as revealed by hydrophobic interaction chromatography. | the luciferin-luciferase bioluminescence method was used to estimate the number of bacteria retained in neutral and amphiphilic gels and those in the eluate to determine the hydrophobic surface properties of bacteria by using hydrophobic interaction chromatography. good correlations were found between viable counts and atp content for escherichia coli, pseudomonas fragi, and listeria monocytogenes. atp determination was more rapid than viable counts for characterizing the relative hydrophobicity ... | 1991 | 1908207 |
| inhibition of food-borne bacterial pathogens by bacteriocins from lactic acid bacteria isolated from meat. | ten strains of bacteriocin-producing lactic acid bacteria were isolated from retail cuts of meat. these 10 strains along with 11 other bacteriocin-producing lactic acid bacteria were tested for inhibitory activity against psychotrophic pathogens, including four strains of listeria monocytogenes, two strains of aeromonas hydrophila, and two strains of staphylococcus aureus. inhibition due to acid, hydrogen peroxide, and lytic bacteriophage were excluded. the proteinaceous nature of the inhibitory ... | 1991 | 1908209 |
| detection and identification of listeria monocytogenes in cooked sausage products and in milk by in vitro amplification of haemolysin gene fragments. | recent outbreaks of listeriosis have emphasized the urgent need for rapid and reliable detection methods for listeria spp., especially in food. haemolysin production is a major factor in the pathogenesis of listeriosis and the polymerase chain reaction (pcr) was used to amplify two specific dna fragments of the alpha- and the beta-haemolysin genes. the amplification system specifically recognized l. monocytogenes strains. the detection limit determined with pure cultures was 10 bacteria when est ... | 1991 | 1908450 |
| a resuscitation/selection system for rapid determination of salmonella in foods. | a resuscitation medium was developed consisting of a trypticase soy broth base supplemented with 0.5% yeast extract, 0.25% sodium pyruvate, 0.01% sodium thioglycollate, and 0.1% chicken fat. after a resuscitation period of 4 h, the medium was made selective by addition of either sodium thiosulfate, bile salts and iodine, or sodium selenite and l-cystine. the now selective medium was incubated for 16 h. the presence or absence of salmonella was determined by the salmonella-tek antibody-based dete ... | 1991 | 1908453 |
| neutrophil-mediated dissolution of infected host cells as a defense strategy against a facultative intracellular bacterium. | the rate of growth of listeria monocytogenes in the livers of mice infected intravenously with a lethal or sublethal inoculum of this facultative intracellular bacterium is greatly increased if neutrophils and other host cells are prevented from accumulating at foci of infection during the first 24 h by treatment with a monoclonal antibody (5c6) specific for the type 3 complement receptor of myelomonocytic cells. a histological examination of the livers of control mice showed that the accumulati ... | 1991 | 1908513 |
| encephalitic listeriosis in two adult llamas (lama glama): clinical presentations, lesions and immunofluorescence of listeria monocytogenes in brainstem lesions. | encephalitic listeriosis was diagnosed in 2 adult llamas. both had a multifocal suppurative encephalitis with mixed lymphocytic and neutrophilic perivascular infiltrates. listeria monocytogenes was cultured from the brain stem of 1 llama using cold enrichment techniques; the other llama was culture negative. formalin-fixed and paraffin embedded sections of brainstem lesions from both affected animals were labeled with a fluorescein-conjugated, anti-l. monocytogenes antibody. using this technique ... | 1991 | 1908758 |
| the occurrence of listeria species in pâté: the cardiff experience 1989. | samples of 216 pâtés were examined for the presence of listeria spp. between may and august 1989; 35% were contaminated with l. monocytogenes, 5% of samples having counts of greater than 10(4)/g. l. innocua was recovered from 2% of samples but no other species was isolated. five serotypes of l. monocytogenes were represented (1/2, 4b, 4b(x), 4 not 4b or 4b(x), and nt), 4b was the predominant serotype and multiple serotypes were found in eight pâtés. the incidence of contamination with l. monocyt ... | 1991 | 1908782 |
| magnetic resonance studies of murine macrophages. proliferation is not a prerequisite for acquisition of an 'activated' high resolution spectrum. | proton magnetic resonance spectroscopy (1h-mrs) was used to investigate the membranes of macrophages activated by gamma-interferon in vitro and by listeria monocytogenes in vivo. we report the appearance with activation, of a high resolution spectrum indistinguishable from that found in activated t and b cells and embryonic and malignant cell types previously studied. we furthermore show that proliferation is not a prerequisite for the appearance of this activated spectrum. this supports the ide ... | 1991 | 1908793 |
| studies on the pathogenicity of listeria monocytogenes. | the characterization of mutants of listeria monocytogenes with reduced virulence properties is described. reduction in the amount of the extracellular protein p60 (encoded by the ipa gene) leads to cell filaments with impaired invasiveness. mutants which cannot synthesize listeriolysin are still invasive but unable to survive within phagocytic cells. one type of listeriolysin-negative mutants is defective in the synthesis of a positive regulatory element prfa which coordinately regulates the lis ... | 1991 | 1908834 |
| effect of various antibiotics on listeria monocytogenes multiplying in l 929 cells. | various antibiotics were evaluated as to their effect on listeria monocytogenes slcc 4013 multiplying within l 929 mouse fibroblast cells. antibiotics were employed in concentrations above the mic value. however, there was no measurable effect of some drugs on intracellular listeriae (azlocillin, mezlocillin, cephalothin, ciprofloxacin, chloramphenicol). with other drugs an inhibition of intracellular growth was observed (penicillin, ampicillin, rifampicin, rifapentine, erythromycin, doxycycline ... | 1991 | 1908835 |
| suppressive effect of a mouse testicular extract on lymphocyte activation. | the effect of mouse testicular extract (te) on lymphocyte activation was investigated. te, in the dose range 75-600 micrograms ml-1, suppressed significantly the blastogenic response of splenocytes to concanavalin a (con-a), pokeweed mitogen (pwm), phytohaemagglutinin (pha) and lipopolysaccharide (lps). te also suppressed the blastogenic response of b-cells to lps and of t-cells to pha in a dose-dependent manner as well as suppressing the mixed lymphocyte reaction (mlr). pretreatment of splenocy ... | 1991 | 1908836 |
| [listeria monocytogenes contamination of raw milk from different regions of anatolia and pasteurized milk sold in ankara]. | in this study 77 raw milk samples from different regions of anatolia and 22 pasteurized milk samples sold in ankara were investigated for isolation of l. monocytogenes. for the isolation of listeria, each sample was plated directly onto mcbride's listeria agar (mla) and on the other hand four processing methods (2 long cold enrichment and 2 shortened warm enrichment procedures, followed by plating) were used. listeria colonies on mla medium were examined by the henry method of oblique lighting. ... | 1991 | 1908939 |
| effects of gamma radiation and azathioprine on brucella abortus infection in balb/c mice. | sublethal irradiation of balb/c mice 4 hours prior to inoculation with 5 x 10(4) virulent brucella abortus, caused significant (p less than 0.01) reductions in bacterial numbers in comparison with numbers in unirradiated controls. numbers of brucellae in the spleen were significantly lower by 5 days after inoculation and decreased thereafter, so that at 2 and 3 weeks after inoculation, there were up to 1,000-fold fewer organisms in the spleen of irradiated mice. the number of brucellae in the sp ... | 1991 | 1909103 |
| microbicidal activities of salmonella typhimurium- and interferon-gamma-activated mouse peritoneal macrophages. | activation of mouse peritoneal macrophages during infection of mice by various facultative intracellular bacteria and after intravenous injection of recombinant interferon-gamma (rifn-gamma) was studied. macrophage activation was demonstrated on the basis of three different criteria, i.e. inhibition of toxoplasma gondii proliferation, enhanced release of h2o2 and increased expression of ia antigen. macrophages activated during an infection with salmonella typhimurium showed no enhanced salmonell ... | 1991 | 1909142 |
| gene disruption by plasmid integration in listeria monocytogenes: insertional inactivation of the listeriolysin determinant lisa. | a plasmid integration technique was developed for insertional inactivation of chromosomal listeria monocytogenes genes. a listeria-escherichia coli shuttle vector (plsv1) was constructed which carried the temperature-sensitive gram-positive replication origin from plasmid ptv32(ts). an internal fragment of the listeriolysin gene (lisa) was cloned into plsv1 to create plsv2. in l. monocytogenes plsv2 transformants, plasmid plsv2 integrated into the l. monocytogenes chromosome at a frequency of 2 ... | 1991 | 1909419 |
| a comparative study of the 'fda' and 'usda' methods for the detection of listeria monocytogenes in foods. | nineteen laboratories across canada took part in a comparative study of the 'fda' and 'usda' methods for the detection of listeria monocytogenes in foods and environmental samples. the results show that the enrichment period of the fda method can be shortened from 7 to 2 days without substantially reducing the number of positive samples. with a limited number of samples, the usda method proved to be slightly more efficient in isolating l. monocytogenes than the fda method. fraser broth, in princ ... | 1991 | 1909544 |
| antagonistic effect of coryneform bacteria from red smear cheese against listeria species. | a total of 187 coryneform bacteria were isolated from red smear and screened for inhibitory effects against 16 strains of listeria species. culture filtrates from brevibacterium linens (16 strains), arthrobacter nicotianae (4 strains) and arthrobacter nucleogenes (3 strains) showed clear zones of inhibition. the antagonistic effect was seen against 26 to 87% of 91 listeria strains tested. a. nicotianae and a. nucleogenes were more effective against listeria innocua and listeria ivanovii than aga ... | 1991 | 1909545 |
| listeria monocytogenes in foods in norway. | three-hundred-and-eighty-two samples of different retail food items in norway (imported soft cheese, raw chicken, minced meat, fermented sausages, vacuum-packed processed meat products, smoked salmon, peeled shrimps, raw minced fish) and 78 carcass samples (sheep, pig, cattle), were screened for listeria monocytogenes. of the 460 samples investigated, 78 were found to contain l. monocytogenes. five of these contained greater than 10(3) cfu/g, four greater than 10(2) cfu/g, while the remainder we ... | 1991 | 1909548 |
| listeria monocytogenes camp reaction. | | 1991 | 1909602 |
| susceptibility testing of listeria monocytogenes. a reassessment of bactericidal activity as a predictor for clinical outcome. | in vitro susceptibility testing of listeria monocytogenes most often reveals both ampicillin and penicillin as inhibitory as opposed to bactericidal with activity comparable to chloramphenicol and tetracycline. yet, the former two penicillins are more effective for listeria meningitis than are the latter agents. accordingly, we reassessed the bactericidal activity of agents used in listeriosis in order to determine in vitro methodology that would be more predictive of clinical outcome. we found ... | 1991 | 1909614 |
| otitis media/interna and suppurative meningoencephalomyelitis associated with listeria monocytogenes infection in a llama. | listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in a 3.5-month-old cria. the cria initially had clinical signs of unilateral peripheral vestibular disease, but on the following day, the cria developed progressive signs of encephalitis. treatment with antibiotics, flunixin meglumine, and anticonvulsant drugs failed to stop progression of the disease, and the cria was euthanatized. post-mortem examination revealed otitis media-interna and diffuse supp ... | 1991 | 1909695 |
| acp broadsheet 129: august 1991. isolation and identification of listeria monocytogenes. | | 1991 | 1909715 |
| characterization of physicochemical forces involved in adhesion of listeria monocytogenes to surfaces. | this study investigated the physicochemical forces involving the adhesion of listeria monocytogenes to surfaces. a total of 22 strains of l. monocytogenes were compared for relative surface hydrophobicity with the salt aggregation test. cell surface charges and hydrophobicity of l. monocytogenes scott a were also determined by electrophoretic mobility, hydrophobic-interaction chromatography, and contact angle measurements. electrokinetic measurements indicated that the strain scott a has a negat ... | 1991 | 1909854 |
| in vitro study of contact-mediated killing of candida albicans hyphae by activated murine peritoneal macrophages in a serum-free medium. | activated peritoneal macrophages obtained from listeria-immune mice were demonstrated to kill nonphagocytosable candida albicans hyphae by contact-mediated mechanisms in a serum-free synthetic medium. the actual killing of hyphae was confirmed by a microculture technique utilizing the dimorphic nature of the fungus. the most efficient candidacidal activity was demonstrated by the macrophages obtained from mice first immunized with live listeria monocytogenes and then elicited with heat-killed l. ... | 1991 | 1910005 |
| dissociated development of t cells mediating delayed-type hypersensitivity and protective t cells against listeria monocytogenes and their functional difference in lymphokine production. | cd4+ t cells mediating both delayed-type hypersensitivity (dth) and acquired cellular resistance (acr) were generated in mice after immunization with viable listeria monocytogenes. in contrast, cd4+ t cells from mice immunized with killed l. monocytogenes in complete freund's adjuvant were capable of mediating only dth but not acr. to determine the functional difference between t cells mediating dth and t cells mediating acr, we examined two different populations of t cells for profiles of lymph ... | 1991 | 1910007 |
| effects of amphetamine on t-cell immune response in mice. | mice chronically injected with amphetamine (0.4 mg/kg/day) showed a reduction in thymus and spleen cellularity, and in peripheral t lymphocyte population. the blastogenic response of spleen lymphoid cells was assessed and amphetamine was found to inhibit t-cell proliferation. amphetamine also reduced the capacity of mice to the development and passive transfer of immunity to listeria monocytogenes. | 1991 | 1910138 |
| bacterial arthritis. | in this review of the 1990 septic arthritis literature, we revisit synovial fluid leukocytosis, examine the utility of synovial fluid glucose and protein measurements, and look at the levels of two cytokines, tumor necrosis factor and interleukin-1, in infected joint fluids. we see the many faces of gonococcal arthritis and the ravages of septic arthritis when the host has rheumatoid arthritis. should we recommend antibiotic prophylaxis for the rheumatoid patient with a prosthetic joint who is u ... | 1991 | 1911055 |
| recovery of listeria monocytogenes on selective agar media in a collaborative study using reference samples. | sixteen laboratories compared counts of listeria monocytogenes in reference samples using blood agar, palcam(y) agar and oxford agar. significant differences were found between laboratories. the mean counts on blood agar were significantly higher than on palcam(y) or oxford agar. the mean counts on palcamy agar were somewhat higher than on oxford agar (only after 48 h incubation), but no significant difference was found. addition of egg yolk to palcam agar seems to be beneficial for the recovery ... | 1991 | 1911086 |
| incidence of listeria monocytogenes in meat production environments of a south island (new zealand) mutton slaughterhouse. | the results of a survey conducted at a south island, new zealand, abattoir are presented. two-hundred-and-eighteen samples taken from ovine carcasses and the environment were analysed. the traditional cold enrichment, i.e. 4 degrees c for up to 16 weeks, was used. no isolations of listeriae were made from freshly dressed carcasses or from surfaces with which meat makes contact. however, seven isolates of listeria monocytogenes were obtained from cold rooms operating at 5 degrees c and which are ... | 1991 | 1911090 |
| growth of listeria monocytogenes in murine macrophages and its modulation by cytokines; activation of bactericidal activity by interleukin-4 and interleukin-6. | bone marrow derived macrophages were infected with a virulent strain of listeria monocytogenes, and the ability of selected cytokines to modify the intracellular growth was assessed. macrophage monolayers pretreated with either interferon-gamma or tumour necrosis factor were shown to exert a significant listericidal activity. treatment of monolayers with granulocyte-macrophage colony stimulating factor led to no significant difference in the ability of listeria to invade and multiply within thes ... | 1991 | 1913336 |
| a 10-year prospective study of women with a history of recurrent fetal losses fails to identify listeria monocytogenes in the genital tract. | an attempt was made to isolate l. monocytogenes from the cervix and endometrium of patients who presented to the dartmouth-hitchcock medical center's reproductive counseling unit with a history of two or more fetal losses. endometrial tissue and endocervical swabs were cultured in a prospective fashion for the presence of l. monocytogenes. during the 10-year study period, none of the patients with recurrent fetal losses were found to harbor the organism in their genital tract. it would appear th ... | 1991 | 1915959 |
| early effects of lead on bone marrow cell responsiveness in mice challenged with listeria monocytogenes. | listeria monocytogenes challenge of lead-treated mice results in increased mortality. since macrophage development constitutes the initial phase of the immune response to l. monocytogenes, bone marrow and spleens from pb-treated mice that were infected with l. monocytogenes were analyzed for their ability to form colonies when exposed to the macrophage growth factor csf-1. serum colony-stimulating activity also was evaluated. data obtained indicate the pb exposure results in decreased responsive ... | 1991 | 1916082 |
| symposium on microbiology update: old friends and new enemies. listeria monocytogenes. | listeria monocytogenes, one of the "new enemies" in food microbiology, is a human and animal pathogen that is widespread in nature. the organism is a transient constituent of the intestinal flora excreted by 1-10% of healthy humans. it is an extremely hardy organism and can survive for many years in the cold in naturally infected sources. l. monocytogenes has been isolated from a wide variety of foods, including dairy products, meats, and fish. although most of the foodborne listeriosis outbreak ... | 1991 | 1917819 |
| pathogenesis of lymphoid lesions in murine experimental listeriosis. | adult female swiss albino mice were infected intraperitoneally or subcutaneously with listeria monocytogenes serovar 4b or 1/2a and killed at intervals. thymus, spleen, peyer's patches and a variety of lymph nodes, including the jejunal (mesenteric), mediastinal, lumbar, mandibular and superficial inguinal, were examined by histopathology and by immunocytochemistry for detection of l. monocytogenes antigen. similar results were obtained with both serovars and by both routes of inoculation used. ... | 1991 | 1918447 |
| role of bacterial hemolysin production in induction of macrophage ia expression during infection with listeria monocytogenes. | the production of a hemolytic exotoxin (hly) termed listeriolysin o (llo) is a major determinant of the virulence of the gram-positive bacterium listeria monocytogenes. as determined by lethal inoculum size, llo- strains of l. monocytogenes generally are several orders of magnitude less virulent than their llo+ counterparts. the generation of protective anti-listeria t cell immunity also has been shown to depend on the llo phenotype of the bacteria present during primary infection, although the ... | 1991 | 1918964 |
| macrophage phagocytosis: use of fluorescence microscopy to distinguish between extracellular and intracellular bacteria. | one of the challenges of phagocytosis research is to differentiate bacteria adherent to a host cell from bacteria which the cell has internalized. to address this question, various techniques such as fluorescence microscopy, electron microscopy, and flow cytometry have been used. we have adapted a flow cytometric method (fattorossi et al., 1989) to use fluorescence microscopy for studying phagocytosis of fluorescein-labeled listeria by inflammatory mouse peritoneal macrophages. in this assay, et ... | 1991 | 1919019 |
| thermal inactivation of listeria monocytogenes studied by differential scanning calorimetry. | the effect of nacl on the thermal inactivation of listeria monocytogenes has been investigated by conventional microbiological techniques and by using differential scanning calorimetry (dsc). addition of 1.5 m-nacl to cells grown at lower nacl concentrations significantly increases the tolerance of cells to mild heat stress (56-62 degrees c). dsc thermograms show five main peaks which are shifted to higher temperatures in the presence of 1.5 m-nacl. measurement of loss of viability in the calori ... | 1991 | 1919516 |
| infected aneurysm of the abdominal aorta due to listeria monocytogenes. | a 79-yr-old man was known for a year with a deteriorating clinical condition, vague abdominal complaints and an elevated erythrocyte sedimentation rate; he was afebrile. extensive evaluation revealed no cause for his progressive disease. eventually an infected aneurysm of the abdominal aorta was diagnosed, from which listeria monocytogenes was cultured. after resection of the aneurysm the patient recovered initially very well. regrettably, therapy-resistant chylous ascites developed, and the pat ... | 1991 | 1922598 |
| pleural fluid infection caused by listeria monocytogenes: case report and review. | nine cases of pleural fluid infection caused by listeria monocytogenes (one case described here and eight cases previously reported in the literature) were reviewed. eight patients (88.9%) had an underlying malignancy (three had hodgkin's disease, three had non-hodgkin's lymphoma, and two had leukemia), and six (66.7%) were receiving immunosuppressive therapy at the time of presentation. seven patients (77.8%) presented with fever and five (55.6%) with respiratory tract symptoms. those with symp ... | 1991 | 1925271 |
| brain abscess caused by listeria monocytogenes. | | 1991 | 1925300 |
| encephalomyelitis with seroconversion to listeria monocytogenes. | a previously healthy girl recovered from a lymphocytic encephalomyelitis with brain stem involvement after antibiotic and steroid treatment. cultures of blood and cerebrospinal fluid were negative, but she seroconverted to listeria monocytogenes serotype 4. antilisterial treatment should be considered in similar cases. | 1991 | 1929521 |
| [listeria monocytogenes nosocomial infection in the maternity ward]. | nosocomial infection with listeria monocytogenes 4b occurred in january 1990 in a maternity hospital in grenoble. the 3 patients involved were born within a 24 hour-interval. the premature newborn responsible for contamination was asymptomatic. two other newborns without any perinatal infectious risk presented with meningitis, one on the 5th day of life in the maternity hospital, the other one on the 11th day while already at home. the 3 strains of listeria had the same serovar and lysovar. epid ... | 1991 | 1929730 |
| listeriolysin negative mutants of listeria monocytogenes specifically stimulate t-lymphocytes mediating protection and granulomatous inflammation. | the ability of several listeriolysin o negative mutants of the virulent egd strain of listeria monocytogenes to activate specific t cell responses in vitro and in vivo was determined. a t cell line and a derived clone specific for listeria monocytogenes, strain egd, which are able to adoptively transfer protection and granuloma formation were examined. specificity testing showed no difference between listeriolysin positive and negative strains to induce proliferation of the t cell lines and clon ... | 1991 | 1930559 |
| comparison of three selective isolation media for the detection of l. monocytogenes in foods. | 391 different foods were examined in order to compare three selective isolation media for listeria: blood agar with nalidixic acid, palcam agar, listeria selective oxford medium (oxford agar). the percentage of positive samples (presence of listeria in 25 g) obtained on the three media after an enrichment procedure is identical: 15.8%. the species l. monocytogenes is found in respectively 8.43%, 8.43% and 8.18% of the foods examined on palcam agar, oxford agar and nalidixic acid agar; this repre ... | 1991 | 1930568 |
| [meningitis caused by listeria monocytogenes in a patient infected by human immunodeficiency virus]. | | 1991 | 1932256 |
| human listeriosis and paté: a possible association. | to study trends in human listeriosis and determine possible sources of infection. | 1991 | 1932944 |
| listeria monocytogenes isolates can be classified into two major types according to the sequence of the listeriolysin gene. | the nucleotide sequence of a 3.5-kb bamhi fragment from listeria monocytogenes 12067, a human clinical isolate of serotype 4b, has been determined. the dna fragment harbors the gene for listeriolysin, part of the gene for a phosphatidylinositol-specific phospholipase c, and part of the gene for a metalloprotease. comparison of the sequence with corresponding sequences from two other l. monocytogenes isolates revealed a significant number of nucleotide differences. several of the differences give ... | 1991 | 1937753 |
| listeriolysin as a virulence factor in listeria monocytogenes infection of neonatal mice and murine decidual tissue. | listeriolysin is a 60-kda protein which allows the growth of listeria monocytogenes in macrophages and other cells and has been shown to be a virulence factor in listeria infections of adult mice. however, the neonate and fetoplacental unit are major populations susceptible to listeriosis. recent data indicate that macrophage and t-cell functions are markedly inhibited in these young mice, and the virulence of listeriolysin-negative (hly-) and listeriolysin-positive (hly+) listeria cells in the ... | 1991 | 1937789 |
| stimulation of monokine production by lipoteichoic acids. | lipoteichoic acids (ltas) isolated from bacterial species, including staphylococcus aureus, streptococcus pyogenes a, enterococcus faecalis, streptococcus pneumoniae, and listeria monocytogenes, were tested for their ability to stimulate the production of interleukin-1 beta (il-1 beta), il-6, and tumor necrosis factor alpha in cultured human monocytes. ltas from s. aureus and s. pneumoniae failed to induce monokine production when applied in the concentration range of 0.05 to 5.0 micrograms/ml. ... | 1991 | 1937822 |
| production and characterization of neutralizing and nonneutralizing monoclonal antibodies against listeriolysin o. | listeriolysin o (llo) is a thiol-activated toxin secreted by the facultative intracellular pathogen listeria monocytogenes. llo is essential for the survival of the bacterium in the infected cell because it promotes lysis of the phagosome membrane and escape of the bacterium into the cytosol. llo was used as an antigen for the production of nine monoclonal antibodies (mabs) in mice. three of these could inhibit the hemolytic activity of llo. one of them inhibited binding of llo to erythrocyte me ... | 1991 | 1937824 |
| effects of macrophage colony-stimulating factor on reduction of viable bacteria and survival of mice during listeria monocytogenes infection: characteristics of monocyte subpopulations. | mice could well tolerate infection with a lethal dose of listeria monocytogenes after intraperitoneal preinjections with 250 micrograms of macrophage colony-stimulating factor (m-csf) per kg of body weight for 5 days. the characteristic changes in the surface markers (mac-1, lfa-1, and f4/80) of peripheral monocytes were also investigated in order to analyze the mechanism of protection by m-csf. this investigation shows the excellent effect of intraperitoneal preinjections of m-csf on the reduct ... | 1991 | 1937827 |
| behaviour of listeria monocytogenes in meat and its control by a bacteriocin-producing strain of lactobacillus sake. | lactobacillus sake lb 706 can release a bacteriocin inhibitory to listeria monocytogenes. in mrs broth, viable counts decreased rapidly when lact. sake lb 706 was added, whereas growth of the listerias was not affected by a bacteriocin-negative variant of the same lactobacillus strain. inhibition of l. monocytogenes was also observed in pasteurized minced meat inoculated with lact. sake lb 706. the bacteriocin produced is apparently effective in meat. however, the effect of the bacteriocin produ ... | 1991 | 1938671 |
| the lethal effect of carrot on listeria species. | when shredded or sliced carrots were inoculated with listeria monocytogenes the number of viable listerias decreased rapidly. on carrot slices stored at 8 degrees c there was a decrease after 3d followed by an increase, after 7d, to numbers similar to those present initially. the numbers of spoilage micro-organisms increased throughout storage at 8 degrees c. carrots macerated in a stomacher lab blender also showed an antilisterial activity which resulted in a decrease in number of viable bacter ... | 1991 | 1938672 |
| thermal inactivation of listeria monocytogenes during a process simulating temperatures achieved during microwave heating. | conventional heating was used to expose cells of listeria monocytogenes, either in broth or in situ on chicken skin, to the mean times and temperatures that are achieved during a 28 min period of microwave cooking of a whole chicken. heating l. monocytogenes by this method in culture broth resulted in a reduction in viable cell numbers by a factor of greater than 10(6) upon reaching 70 degrees c. simulated microwave cooking of l. monocytogenes in situ, on chicken skin, resulted in more variabili ... | 1991 | 1938673 |
| treatment failure and recurrent human listeriosis. | we review 12 patients and report an additional two new patients, each of whom had two episodes of listeriosis. in seven patients the two episodes were due to the same strain of listeria monocytogenes, and we speculate that this was a reactivation of the original infection. in one patient, isolates of l. monocytogenes from the two episodes differed, suggesting a chance reinfection. twelve of the patients in this series received inappropriate therapy. ampicillin plus an aminoglycoside for three to ... | 1991 | 1938692 |
| listeria monocytogenes, a food-borne pathogen. | the gram-positive bacterium listeria monocytogenes is an ubiquitous, intracellular pathogen which has been implicated within the past decade as the causative organism in several outbreaks of foodborne disease. listeriosis, with a mortality rate of about 24%, is found mainly among pregnant women, their fetuses, and immunocompromised persons, with symptoms of abortion, neonatal death, septicemia, and meningitis. epidemiological investigations can make use of strain-typing procedures such as dna re ... | 1991 | 1943998 |
| synthetic vaccines. peptides of fortune. | | 1991 | 1944552 |
| bactericidal potency and mechanistic specificity of neutrophil defensins against bovine mastitis pathogens. | two neutrophil defensins, rabbit peptides np-1 and np-5, were examined for their in vitro antibacterial activity against a panel of gram-positive and gram-negative organisms isolated from mastitic cows. incubation for 60 minutes with 5 micrograms/ml of np-1 in 10 mm sodium phosphate buffer resulted in substantial killing (greater than 95%) of all organisms tested. although np-5 was virtually inactive under these same conditions, supplementation of the incubation mixture with dilute nutrient medi ... | 1991 | 1949554 |
| [listeria abortions in cattle--bacteriology, serology and epizootiology]. | listeria abortions were established in foetuses of cattle in 1.2% of the cases investigated in the erfurt region and 1.8% in the cottbus region from 1984 to 1989. the isolated strains have been found biochemically to be l. monocytogenes. the serological discrimination revealed a majority of serovar o i, ii. typing by phages of a part of isolated strains showed a clear predominance of code number 000 124 by the 1/2 a isolate (corresponds to o i, ii). this type of phages seems to have a epizootiol ... | 1991 | 1953632 |
| physiological evaluation of stimulated growth of listeria monocytogenes by pseudomonas species in milk. | experiments were designed to elucidate a possible physiological mechanism for stimulated growth of listeria monocytogenes by pseudomonas fluorescens in milk. the ability of l. monocytogenes to grow in milk under aerobic and microaerophilic environments was compared. neither environment favored the growth of the organism at 10 degrees c. autoclaved whole milk was inoculated with p. fluorescens p26 and preincubated for 3 days at 10 degrees c followed by inoculation with l. monocytogenes scott a an ... | 1991 | 1954572 |
| characteristics of nonpathogenic strains of listeria monocytogenes. | five strains of nonpathogenic listeria monocytogenes were characterized for (i) hemolysin production, (ii) cytolysis of chinese hamster ovary (cho) cells, and (iii) ability to attach and enter intestine 407 cells. four of the five strains produced variable hemolysis and were weakly cytolytic for chinese hamster ovary cells, whereas the other isolate was consistently hemolytic and strongly cytolytic for cho cells. none of the strains was able to penetrate intestine 407 cells. in addition, two of ... | 1991 | 1954578 |
| detection and prevalence of listeria monocytogenes in the agricultural ecosystem. | the sensitivity of four different enrichment procedures to detect listeria monocytogenes in the presence of high levels of streptococcus faecalis was investigated. defined mixed cultures of strep. faecalis and l. monocytogenes gave better results with one-stage enrichment techniques. for manure samples, however, two-stage enrichment techniques gave the best performance. the so-called cold enrichment techniques were found to be unsatisfactory for samples from natural environments. the following m ... | 1991 | 1955415 |
| the adsorption of bacteria to immobilized lectins. | the agglutination of a selection of bacteria by some lectins was examined. the lectin from codium fragile agglutinated seven strains of salmonella typhimurium. the lectin from helix pomatia agglutinated eight of 12 strains of listeria monocytogenes and a further two strains gave a weak agglutination reaction. helix pomatia lectin conjugated to magnetic microspheres enabled the adsorption of l. monocytogenes from suspension with subsequent elution by the competing ligand n-acetyl galactosamine. a ... | 1991 | 1955420 |
| vancomycin therapy failure in listeria monocytogenes peritonitis in a patient on continuous ambulatory peritoneal dialysis. | | 1991 | 1955728 |
| evaluation of monoclonal antibodies to listeria monocytogenes flagella by checkerboard elisa and cluster analysis. | a simple elisa technique is described which utilizes whole bacteria as solid phase antigens for the evaluation of monoclonal antibodies against flagellar proteins of listeria monocytogenes. cluster analysis of the elisa extinction values gave distinct reaction patterns from 23 tested supernatants. the method offers the possibility of screening supernatants without the necessity for standardization of antibody concentration or the labelling of established monoclonal antibodies. | 1991 | 1960399 |
| subtyping of listeria monocytogenes serovar 4b by use of low-frequency-cleavage restriction endonucleases and pulsed-field gel electrophoresis. | pulsed-field gel electrophoresis (pfge) was used to compare the limited number of large restriction fragments generated by digesting dna of listeria monocytogenes strains with restriction enzymes characterized by rare recognition sequences. sixteen macro-restriction patterns were observed with apai and smai, and 7 with noti, among 42 strains of serovar 4b, the most important serovar in human listeriosis epidemiology. analysis of these restriction fragment length polymorphisms enabled a rapid dif ... | 1991 | 1961978 |