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Effect of osmotic, alkaline, acid or thermal stresses on the growth and inhibition of Listeria monocytogenes

JOURNAL OF APPLIED MICROBIOLOGY 1999年第3期86卷 469-476页

作者： Vasseur, C Baverel, L Hébraud, M Labadie, J INRA Rech Viande Stn Unite Rech Microbiol F-63122 St Genes Champanelle France

Five strains of Listeria monocytogenes (a, b, c, d and e) isolated from industrial plants have been subjected to different osmotic, alkaline, acid or thermal stresses. The effects of these treatments on lag-phase (L) and growth rate (mu) of cells in mid-log phase have been followed using an automated optical density monitoring system. Increasing the osmotic pressure by the addition of different amounts of NaCl increased the lag phase and decreased the growth rate. The same phenomena were observed after decreasing the pH of the medium to 5.8, 5.6 or 5.4 by addition of acetic, lactic or hydrochloric acids. The inhibitory effect was: acetic acid > lactic acid > hydrochloric acid. The addition of NaOH to attain pH values of 9.5, 10.0, 10.5 or 11.0 in the medium produced a dramatic increase of the lag phase at pH 10.5 and 11. Growth rates were also decreased while the maximal population increased with high pH values. These effects varied according to strains. Strains d and e were the most resistant to acidic and alkaline stresses, and e was the most affected by the addition of NaCl. A cold shock of 30 min at 0 degrees C had limited effects on growth parameters. On the other hand, hyperthermal shocks (55 or 63 degrees C, 30 min) led to similar increased lag phases and to significant increases of the maximal population in all five strains.

关键词：醋酸/药理学碱类/药理学细胞分裂/药物作用细胞分裂/生理学热氢离子浓度乳酸/药理学利斯特菌单核细胞增生/药物作用利斯特菌单核细胞增生/生长和发育渗透压氯化钠/药理学温度

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Characterization, production, and purification of leucocin H, a two-peptide bacteriocin from Leuconostoc MF215B

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CURRENT MICROBIOLOGY 1999年第1期39卷 43-48页

作者： Blom, H Katla, T Holck, A Sletten, K Axelsson, L Holo, H Norwegian Food Res Inst MATFORSK N-1430 As Norway Norwegian Dairies R&D Ctr TINE Oslo Norway Agr Univ Norway Lab Microbial Gene Technol N-1432 As Norway Univ Oslo Dept Biochem N-0367 Oslo Norway

Leuconostoc MF215B was found to produce a two-peptide bacteriocin referred to as leucocin H. The two peptides were termed leucocin H alpha and leucocin H beta. When acting together, they inhibit, among others, Listeria monocytogenes, Bacillus cereus, and Clostridium perfringens. Production of leucocin H in growth medium takes place at temperatures down to 6 degrees C and at pH below 7. The highest activity of leucocin H in growth medium was demonstrated in the late exponential growth phase. The bacteriocin was purified by precipitation with ammonium sulfate, ion-exchange (SP Sepharose) and reverse phase chromatography. Upon purification, specific activity increased 10(5)-fold, and the final specific activity was 2 X 10(7) BU/OD280. Amino acid composition analyses of leucocin H alpha and leucocin H beta indicated that both peptides consisted of around 40 amino acid residues. Their N-termini were blocked for Edman degradation, and the methionin residues of leucocin H beta did not respond to Cyanogen Bromide (CNBr) cleavage. Absorbance at 280 nm indicated the presence of tryptophan residues and tryptophan-fracturing opened for partial sequencing by Edman degradation. From leucocin H alpha, the sequence of 20 amino acids was obtained;from leucocin H beta the sequence of 28 amino acid residues was obtained. No sequence homology to other known bacteriocins could be demonstrated. It also appeared that the two peptides themselves shared little or no sequence homology. The presence of soy oil did not affect the activity of leucocin H in agar.

关键词：氨基酸序列芽孢杆菌蜡状/药物作用细菌素类/遗传学细菌素类/分离和提纯细菌素类/代谢细菌素类/药理学色谱法离子交换梭菌产气荚膜/药物作用明串珠菌属/代谢利斯特菌单核细胞增生/药物作用分子序列数据

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Foodborne listeriosis

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CLINICAL INFECTIOUS DISEASES 2000年第3期31卷 770-775页

作者： Schlech, WF QEII Hlth Sci Ctr Div Infect Dis Halifax NS B3H 2Y9 Canada

Listeria monocytogenes emerged as an important foodborne pathogen in the latter part of the 20th century Clinical syndromes caused by this microorganism include sepsis in the immunocompromised patient, meningoencephalitis in infants and adults, and febrile gastroenteritis. Focal infections at other sites are less frequent. Listeria species are commonly found in raw and unprocessed food products. Major outbreaks of listeriosis, with high morbidity and mortality, have been caused by a variety of foods, including soft cheeses, delicatessen meats, and vegetable products. Improved detection methods, dietary recommendations, and, in some cases, preemptive antibiotic treatment or prophylaxis have reduced the incidence of sporadic listeriosis infections in the United States. Microbial virulence factors distinguishing environmental strains of L. monocytogenes from invasive strains causing foodborne illness and host factors promoting human infection remain incompletely understood.

关键词：抗菌药/治疗应用食品微生物学食物中毒/微生物学食物中毒/预防和控制利斯特菌感染/诊断利斯特菌感染/微生物学利斯特菌感染/预防和控制利斯特菌单核细胞增生/药物作用利斯特菌单核细胞增生/分离和提纯利福平/治疗应用甲氧苄啶磺胺甲异恶唑合剂/治疗应用万古霉素/治疗应用成年人人类婴儿

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Nisin and ALTA™ 2341 inhibit the growth of Listeria monocytogenes on smoked salmon packaged under vacuum or 100% CO₂

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LETTERS IN APPLIED MICROBIOLOGY 1999年第5期28卷 373-377页

作者： Szabo, EA Cahill, ME Food Sci Australia N Ryde NSW 1670 Australia Cooperat Res Ctr Int Food Manufacture & Packaging N Ryde NSW Australia

The effects of nisin and ALTA(TM) 2341 on the growth of Listeria monocytogenes were assessed on smoked salmon packaged under vacuum or 100% CO2. Smoked salmon slices (pH 6.3) were inoculated with a cocktail of seven L. monocytogenes isolates at a level of approximately 2.5 log(10) colony forming units (cfu) g(-1). After inoculation, the surface of the smoked salmon slices was treated with either nisin (400 or 1250 IU g(-1)) or ALTA(TM) 2341 (0.1 or 1%). The smoked salmon was packaged and stored at 4 degrees C (28 d) or 10 degrees C (9d). On untreated vacuum-packaged smoked salmon, L. monocytogenes grew by 3.8 log(10) cfu g(-1) at 4 degrees C and 5.1 log(10) cfu g(-1) at 10 degrees C. Growth was reduced on nisin- and ALTA(TM) 2341-treated vacuum-packaged smoked salmon. On the nisin-treated samples, L. monocytogenes increased by 2.5 (400 IU g(-1)) and 1.5 (1250 IU g(-1)) log(10) cfu g(-1) at 4 degrees C, and by 4.3 (400 IU g(-1)) and 2.7 (1250 IU g(-1)) log(10) cfu g(-1) at 10 degrees C. With the ALTA(TM) 2341-treated samples, L. monocytogenes increased by 2.8 (0.1%) or 1.6 (1.0%) log(10) cfu g(-1) at 4 degrees C, and 3.3 (0.1%) or 3.6 (1.0%) log(10) cfu g(-1) at 10 degrees C. The growth of L. monocytogenes was retarded by packaging the smoked salmon in 100% CO2. On untreated smoked salmon only a 0.8 log10 cycle increase was observed at 10 degrees C. Under all the other conditions tested with 100% CO2, L. monocytogenes was detected but growth was prevented.

关键词：细菌素类/药理学二氧化碳/药理学鱼制品/微生物学食品包装/方法食品防腐剂/药理学利斯特菌单核细胞增生/药物作用乳链球菌素/药理学真空

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The ketolide antibiotic HMR 3647, a candidate substance for the treatment of systemic and intracerebral infections with Listeria monocytogenes

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Zentralblatt fur Bakteriologie 1999年第2期289卷 155-164页

作者： Nichterlein, T. Kretschmar, M. Hof, H. Inst. Med. Microbiol. Hyg. Mannheim Faculty of Clinical Medicine University of Heidelberg 68167 Mannheim Germany Inst. Med. Microbiol. Hyg. Mannheim D-68167 Mannheim Theodor-Kutzer-Ufer 1 Germany

HMR 3647 is a novel macrolide derivative with a broad spectrum of activity against grampositive bacteria and some fastiduous gramnegative bacteria, anaerobes and Toxoplasma gondii. In this work, its activity against the facultatively intracellular bacterium, Listeria monocytogenes, was examined in vitro, in tissue culture and in animal models of systemic and intracerebral infection and compared with that of erythromycin. All strains of L. monocytogenes were susceptible to the substance, with minimal inhibitory concentrations (MICs) that were consistently lower than the MICs of erythromycin. HMR 3647 was bacteriostatic against L. monocytogenes since concentrations of up to 64 times the MIC did not kill the bacteria within 24 hours. HMR 3647 produced a pronounced postantibiotic effect (PAE) and was bacteriostatic in tissue culture cells infected with L. monocytogenes. In animal models of systemic and intracerebral infection, HMR 3647 was slightly more effective than erythromycin in the livers and spleens and comparably effective in the brains when given in the same dosage. In conclusion, HMR 3647 is a candidate substance for the treatment of infections with L. monocytogenes in immunocompetent subjects.

关键词：抗菌药/药理学抗菌药/治疗应用脑疾病/药物疗法脑疾病/微生物学细胞系疾病模型动物酮内酯类抗生素利斯特菌感染/药物疗法利斯特菌感染/微生物学利斯特菌单核细胞增生/药物作用大环内酯类微生物敏感性试验动物女(雌)性小鼠

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