Phage-typing of Listeria.
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Biomedical subjects
Publications and source records attributed to S Ortel.
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In the period from 1980-86 we obtained 51 strains of Listeria from meningitis in adults for serotyping and phage-typing. Ten strains were associated with meningitis and 3 with septicaemia of immunocompromised patients. They suffered from leukaemia, diabetes, Hodgkin's disease, alcoholism, lupus erythematodes. The lethality rate in these patients was 70%, in other patients with meningitis 30%. Phage typing has shown that 4b strains were often determined by the phage-code 00010 and similar codes. This phage-pattern might be specific for meningitis strains. The immunocomprised patient is especially endangered in taking up listeriae from the environment, but it must also be in consideration that listeriae may easy gain access from the gut into the vessels.
Results of phage-typing of 22 strains from 16 listeriosis cases, which were isolated during an epidemic outbreak in the district of Magdeburg, showed that most strains were determined by the octal codes 73611, 73615, 73655, 73645. We suppose that this was the epidemic strain, although also other phage-patterns (40000, 00600, 03200) were found. The source of the epidemic outbreak could not cleared up. The purpose of further investigations was to establish how far phage-patterns of Listeria from the same patients from different materials might be identified as identical, similar or different. We give examples of typing results in 1/2a and 4b strains and compare the results concerning an significant or non-significant alteration.
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The aim of this multicenter study was to determine and to standardize methods in order to have common basis for comparing results of phage typing of Listeria monocytogenes. Using a common set of Listeria strains, a standardized method, including media, bacterial growth conditions, application of viruses and reading of lytic reactions, was established. 29 bacteriophages were selected according to their host range. This phage typing system allowed phagovar determination of 54% of the serogroup 1/2 strains and 77% of the serogroup 4 strains of L. monocytogenes.
Seventeen Listeria phages have isometric heads and long, noncontractile tails. Twelve of them belong to three already known phage species. Five phages represent a new species, named H387.
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Ninety-eight (39.6%) out of 247 Listeria monocytogenes strains isolated from a variety of sources were typable by 27 phases. Of the 31 human strains only 3 belonged to phage types occurring in cattle, sheep and surface waters. A close correlation existed between serotype and phage type of the strains. Serotype 1/2 and 4 strains isolated in Hungary were less frequently typable than cultures originating from France. Phage typing is a useful tool for epidemiological tracing but, for a more effective differentiation, the number of phages should be increased and the method should be standardized.
In former years, especially between 1963 and 1969, in the GDR the listeriosis of pregnants, prematures, and newborns played a significant role, and the infantile mortality was influenced in a most unfavourable way. Since 1970 frequency of listeriosis diminished definitely in the GDR. - We present the route of embryo-infection of the most frequently occurring connatal listeriosis and the consequences there of for mother and child. - Investigations on Listeria-excretion in pregnants show that 34 (= 31%) of 110 morefold examined pregnants excreted Listeria in their feces. Particularly the distribution of serovars, excretion frequency with regard to duration of pregnancy, season, as to primipara and multipara was investigated. All 34 excretors are delivered of healthy babies. A treatment with antibiotics of pregnants excreting Listeria is no longer recommended. - With reference to the epidemiology, listeriosis should be indicated as geonosis or sapronosis because the infectious reservoir is the human environment. The bacteriological diagnosis of listeriosis can be accomplished with approved and successful methods especially the storage of specimens in thioglycolat broth at + 4 degrees C over a period of 26 weeks and the cultivation on tryptose-agar with nalidixine acid and trypaflavin. - Chemotherapeutics for infected mothers, adults, and newborns are the ampicillins, the ureidopenicillins, and antibiotic-combinations (ampicillin with gentamycin). Preventive measures are especially the avoidance of dirt- and smear-infections and the contact with ill animals. In maternity hospitals infected mothers should be separated to elude hospital infections; the same request is accepted in newborn wards.
Under aerobic conditions Staph. aureus was isolated in 40%, grampositive germs were as frequent as gramnegative bacteria. Bacteroides fragilis was the predominant germ from material suspicious of an anaerobic infection. For its isolation the material should be sent as soon as possible to the laboratory to be investigated under anaerobic conditions. The author stresses the close cooperation between the clinician and the microbiologist to receive optimal diagnostic results as the basis of an effective chemotherapy.
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56 Listeria strains isolated from the intestine contents of 13 species of micromammalia in Bulgaria were studied. 10 of the strains belong to the serovars 1/2a, 4A, 4b and 5 of Listeria monocytogenes and 44 of the strains belong to 10 antigenic variants of Listeria innocua. According to their characteristics these strains could hardly cause diseases in humans or domestic animals. Two strains have antigenic formulae O-V, VII, XIV and O-V, XIV and cannot be included in the existing classification. Prevalent are the strains antigen O-XV. They are more often isolated from synanthropic rodents. The hemolytic properties of the studied strains have the best correlation with the pathogenicity. The decomposition of rhamnose and xylose and the production of lysozyme could be a suitable basis for their classification in biotypes.
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By means of mitomycin induction monocine preparations were made from 162 Listeria monocytogenes strains. From tested strains of different serovars and antigen combinations altogether 76% were monocinogenic. Examination of efficiency was performed against 15 indicator strains of Listeria monocytogenes. Concluding from spectra of reaction 6 groups of monocines (A-F) could be differentiated. Serovar 5 (Ivanov) proved as an indicator strain particularly sensitive for all monocines.
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