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B Ralovich

Publications and source records attributed to B Ralovich.

At least 19 recordsLinked to original sources
PubMed1997

Problems of microbial zoonoses in Hungary. (A review).

Hungarian data of 36 zoonotic diseases are summarized. These illnesses cause problems not only for health, public health and veterinary health services but for the society and their importance has increased. Changing character of an old pathogen (Salmonella enteritidis PT4) resulted in new epidemiological situation. The number of cases of food-borne zoonotic diseases has rapidly grown. The number of pets has elevated and in consequence the possibility of an infection of owners, breaders, sellers and other persons has also grown. Growing number of HIV positive patients as well as ill persons treated with immunosuppressive drugs increases the importance of opportunistic zoonotic pathogens (Cryptosporidium, Toxoplasma). The most effective and less expensive way to prevent an exposed population is the active immunization (BCG, tetanus, tick-borne encephalitis). Active immunization of animals can also reduce probability of human infections and economic losses (leptospirosis, rabies). In special cases it is advised to perform eradication programmes to get pathogenic-free domestic animals (brucellosis, bovine tuberculosis, salmonellosis, campylobacteriosis). Permanent surveillance is obligatory to recognize changing nature of pathogens, alteration of epidemiological situation and to identify areas for further research. Continuous education of population in general and special teaching of risky groups are very important for an effective prevention.

Animals↗
PubMed1996

Occurrence of Listeria and listeriosis in Hungary.

Listeriosis is a rare human disease in Hungary. The number of cases is slowly increasing. Only sporadic events have been observed but the occurrence of epidemic listeriosis may be supposed. The Listeria monocytogenes (in abbreviation: L. m.) transmitter role of food in human infections has not yet been verified. The epidemiological character of animal listeriosis is different. Healthy carriers can be found among both humans and animals. Foodstuffs of animal as well as plant origin may be contaminated with Listeria. When the processing technology and/or hygienic conditions are not satisfactory, these microorganisms can be detected in food factories and in final products of the food industry.

Animals↗
PubMed1992

Data for the properties of Listeria strains (a review).

It seems that taxonomy of listeriae is in a fluid stage. Between beta-haemolytic property and virulence of these bacteria a strong relationship has been demonstrated. These characters are coded by hlyA gene which seems to belong to a monocistronic unit. Virulent Listeria strains possess specific surface antigens and can enter as well as multiply in host cells. Their exact human virulence is not known. Listeriae can grow from around 0 to 42 degrees C and can survive either the effect of frost or of temperature of 48 degrees C. They may form biofilm on different surfaces. Their growth kinetics, persistance and heat resistance can be influenced by many factors (type of growth environment, pH, acidulants, salts, chemicals, antibiotics, plant substances, enzymes, humidity, atmosphere, temperature, prior temperature-effects, microbial competition and the length of influences). Radiation sensitivity of Listeria is usual. Plasmid mediated antibiotic resistant mutant of Listeria monocytogenes is verified.

Food Microbiology↗
PubMed1991

[Problems of listeriosis].

The first human listeriosis case was diagnosed in 1965 in Hungary. Since that time about 90 bacteriologically verified cases have been recognized. The half of the cases occurred in pregnant women and newborns. 45% of the patients died. The author reports the newest information about characteristics and ecology of Listeria strains and epidemiology of listeriosis. So, importance of hygienic animal husbandry and food production, transmitter role of foods, possibilities of prevention, treatment and diagnostic methods are mentioned in this paper.

Animal Husbandry↗
PubMed1991

Model examination of selective media for isolation of Listeria strains.

During the Tenth International Symposium on Listeriosis (Pécs, Hungary, 1988) the Working Party on Culture Media of IUMS-ICFMH suggested comparative examination of nine enrichment broths and nine solid selective media. On the basis of this proposal the following media were studied: LiCl-phenylethanol-moxalactam agar (LPM), polymyxin-acriflavine-LiCl-ceftazidime-aesculin-mannitol agar (PALCAM) No. 1 (home made) and No. 2 (Merck), acriflavine-ceftazidime agar (AC), Oxford agar, tripaflavine-nalidixic acid serum agar (TNSA) and Forray's agar. The study was performed as described in "Testing methods for use in quality assurance of culture media". Oxford agar proved to be the best medium. LPM, AC and Forray's agars were somewhat more inhibitory than Oxford medium. In productivity TNSA and PALCAM media were weakest but the latter one was more selective. When 43 sausage samples were enriched in UVM broths and subcultured on the above mentioned media the number of positive samples was the same on Oxford, LPM, AC and TNSA agars but it was lower on PALCAM agar No. 1. When 103 milk samples were subcultured on TNSA and PALCAM agar No. 2, the number of positive samples was the same.

Agar↗
PubMed1991

What is the diagnostic value of beta-D-glucuronidase (BDG) activity of bacteria using Fluorocult ECD agar for their cultivation?

A total of 1510 strains from 15 genera of Gram-negative and Gram-positive bacteria were studied. More than 94% of 327 Escherichia coli strains showed beta-D-glucuronidase (BDG) activity. Seventeen serotypes from 170 E. coli O serogroup representatives were negative. Relationship between the existence of BDG positive and negative E. coli strains in the same serogroup or serotype has not been observed. The rate of BDG positivity was 42% among Salmonella arizonae strains and 42.2% among Shigella strains. Only one Citrobacter strain out of the 971 strains belonging to Citrobacter, Edwardsiella, Enterobacter, Hafnia, Klebsiella, Proteus, Serratia, Yersinia, Pseudomonas, Aeromonas, Vibrio and Listeria was BDG positive. A screening method based on only BDG activity is not sufficient for the primary diagnosis of E. coli.

Agar↗
PubMed1991

Meditation of the taxonomy of Listeria.

Listeria monocytogenes was exactly identified and named in 1924. Since then the name and taxonomic position of listeriae have been changed several times. The last classification was performed on the basis of genetic studies and of some biological properties (haemolytic character, virulence and acid production from sugars). On the basis of the taxonomic validity of these characters, the Listeria genus is proposed to be classified into three species: L. monocytogenes (four subspecies), L. ivanovii and L. grayi (two subspecies).

Bacterial Typing Techniques↗
PubMed1991

beta-D-glucuronidase (BDG) activity of gram-negative bacteria.

BDG is an inducible enzyme that is encoded by the uidA gene in Escherichia coli. Genetic sequences of this gene are present in most if not all E. coli strains regardless of the BDG phenotype. Expression of BDG activity can be influenced by lactose-induced catabolite repression or genetic mutations. Salmonella, Shigella and Yersinia strains frequently exhibit positive BDG reaction. BDG activity of strains belonging to genus Edwardsiella, Serratia, Yersinia, Vibrio, Erwinia, Alcaligenes, Acinetobacter, Moraxella, Plesiomonas, Achromobacter, Flavobacterium, Chromobacterium and Pasteurella awaits examination.

Animals↗
PubMed1990

Haematological reactions of rabbits infected intravenously with Listeria strains of different virulence.

Listeria strains of different virulence were injected intravenously into rabbits of both sexes (2-4 kg). The infectious dose was 10(8) cells/kg. Blood samples were taken from the ear wein one day and immediately before the infection, then 3 h, 1, 2, 3, 6 and 10 days after it. Total white blood cell counts and their changes were determined and the number of lysosomal granules in neutrophils were counted. A marked monocytic reaction was observed after the injection of virulent Listeria monocytogenes 18 and 87/5467, partly virulent Listeria ivanovii, non-pathogenic Listeria seeligeri 87/5626 and 87/5575, and Listeria murrayi G44 strains. A late slow growth was provoked by Listeria innocua C644 and a very slight reaction by Listeria welshimeri 1830 strains. There was no change after injection of L. innocua strain 10. The number of lysosomal granules decreased significantly and remained at a low level for 6 days after the infection of L. monocytogenes strain 18 and for 3 days after the injection of L. innocua strain 10.

Animals↗
PubMed1989

Differentiation of Listeria and Streptococcus strains.

Colonial morphology of non-beta haemolytic Listeria strains is frequently similar to that of non-haemolytic streptococci. Biochemical characteristics, motility, haemolysis on ox blood agar, growth on Clauberg, selective streptococcus (Si) and Mitis-Salivarius agar medium, CAMP test, serological behaviour of 16 Listeria strains were studied and the results were compared with the properties of Streptococcus strains. Microscopic morphology, motility and catalase activity are useful for distinguishing these strains. To avoid a false diagnosis, latex-agglutination should be supplemented with the above tests.

Listeria↗
PubMed1986

Alteration of phage- and biotypes of Listeria strains.

Ethyl-methyl-sulphonate mutants of Listeria monocytogenes might be different from the parent strain in phage type and in splitting of lactose, maltose, melezitose, sucrose and trehalose. Differences were observed in repeated control studies in phage type and carbohydrate-decomposition of 550 Listeria strains isolated from a variety of sources (patients, healthy and dead animals). It has been concluded that certain carbohydrate tests are unsuitable for distinguishing biotypes of Listeria. An improvement of the evaluation of phage typing results is recommended.

Animals↗
PubMed1986

Comparison of Listeria serotypes and phage types isolated from sheep, other animals and humans.

A total of 814 different faecal, nasal, vaginal and milk samples of 50 healthy cotted sheep was investigated for Listeria during an epidemic-free summer season. Forty ewes and 5 tegs excreted Listeria strains; 18.1% of all samples were positive. A total of 151 Listeria monocytogenes strains belonging to serotypes 1/2, 4, 5, 6 and unknown were identified and phage typed. On the basis of the serotype and phage type of the excreted strains the animals could be divided into 7 groups. Characters of strains isolated from the cotted sheep were compared with those cultivated from 68 dead animals received from 44 distinct settlements. Also properties of 10 Listeria strains originating from 8 ill patients infected in the same region from where the carcasses of the animals were sent to the laboratory were studied. Two human Listeria strains were identical in serotype and phage type with some animal strains.

Adult↗
PubMed1986

Computer analysis of some bacteriological, biological and physiochemical parameters of the coastal water of Lake Balaton.

Some 61 coastal water samples were taken at four definite points of Balaton Lake. Seventeen parameters of each sample characterizing the quality of the water were studied by means of multiple correlation and regression analysis, one-way variance analysis and by factor analysis with the help of BMD computer program. Uni- and multilateral relationships could be observed among the single parameters. On the basis of the results of factor analysis six factors--phytoplankton system, anthropogenic effect, own bacterial system of the lake, nitrogen circulation, hydrocarbonate and reactive phosphate system and NH+4 circulation--could be separated. Significant qualitative differences could be found along the longitudinal axis of Balaton. It could be also demonstrated that the water of the lake in its present condition is suitable for the proliferation of bacteria. Further and deeper examinations are necessary for a better understanding of the biochemical and biological processes.

Analysis of Variance↗