Genetic identification of rickettsiae of the tick-borne spotted fever group, isolated in the foci of tick-borne rickettsiosis

A total of 25 rickettsial cultures of the tick-borne spotted fever (TBSF) group from the collection of the Research Institute of Infections in Omsk, isolated from different sources in the territory of the Russian Federation (from the Urals to the Far East) during the period of 1954-2001) were studied by the methods of genetic analysis. The fragments of the gene coding the outer-membrane protein of 190 kD (ompA) and synthetase citrate (gltA) of the rickettsiae under the study were sequenced. 23 isolates were identified as R. sibirica, among them 3 isolates obtained from patients, 16 isolates obtained from Dermacentor ticks, 2 isolates from Haemaphysalis concinna and 2--from Ixodes persulcatus. The strain Primorye 32/84, isolated from D. silvarum ticks in the Far East and earlier identified as S. sibirica by the results of the PCR-RFLP analysis proved to be a genovariant Rickettsia spBJ-90, i.e. close to this species. Strain Karpunino 19/69, isolated in the Kurgan region, was identified as R. slovaca. The results obtained extended our notions of the spectrum of rickettsiae group TBSF in Russia as well as their vectors.     

Comparative evaluation of diagnostic preparations

The diagnostic value of preparations is commonly characterized by sensitivity and specificity. But not all these characteristics make it possible to decide unequivocally which of the preparations to be compared is superior to the other one with respect to its diagnostic value. It is proposed that in the choice of a diagnostic preparation its capacity to provide data for exact diagnosis should be considered, i.e. the additional characteristic indicating the spread of the disease under study. As an example, the comparison of the diagnostic value of conventional methods and the polymerase chain reaction in the diagnostics of helicobacteriosis is presented. The described method for the evaluation of the diagnostic value of the preparation is well-grounded, simple and obvious.     

Adhesiveness and antibiotic resistance of the causative agents of salmonella infection in Gomel' region

The adhesive capacity, resistance to antibiotics and biological properties of Salmonella strains of different serogroups, circulating in the Gomel region, were under study. Resistance to antibiotics and changes in biological properties were accompanied by an increased adhesiveness of these strains. A high degree of adhesiveness was noted in S. hadar, a new for Belarus strains.     

Characterization of antirubella vaccine in an epidemiological trial

The work was aimed at the evaluation of the antigenic activity and reactogenicity of antirubella vaccine, manufactured by the Serum Institute of India, on the basis of the active observation of 373 children. Vaccinal reactions were registered in 8.8% of the vaccinees. Seroconversion after the injection of the vaccine was 100%. The results of the epidemiological trial demonstrated that the Indian antirubella vaccine was faintly reactogenic and had high antigenic activity.     

Spread of salmonellosis in Moscow and the ways of its prophylaxis

The article deals with the results of the epidemiological analysis of the spread of salmonellosis in Moscow. During the last 15 years the proportion of Salmonella enteritidis was about 80% and more. After salmonellosis morbidity decreased to 19.9 per 100,000 of the population (the minimum level) in 1985 its sharp rise was noted. Morbidity rate increased from 31.7 in 1987 to 55.1 per 100,000 in 1988, then to 93.9 per 100,000 of the population in 1989 (the maximum level). In the subsequent years up to 1996 a decrease in morbidity rate was observed, but in 1997-2002 morbidity rate stabilized within 29.8-35.7 per 100,000 of the population without a perceptible tendency towards decrease. The sharp increase of the etiological role of S. enteritidis which led to a wide spread of Salmonella infections was caused by the "chicken-egg" factor of their transmission. High morbidity rate among children and adults, registered all the year round, is the consequence of the constant epidemic activity of this factor.     

Properties of the isolated Bacillus subtilis strains and their influence on the intestinal microflora of experimental mice

The cultural, physiologo-biochemical adhesive and antagonistic properties of B. subtilis strains with good prospects for use as biotherapeutic preparations were studied. For further studies B. subtilis strain No. 1719 was chosen. In experiments on non-inbred white mice the animals were treated by the preparation Cifran used for their selective decontamination from opportunistic microflora and for the creation of the state of dysbiosis. The influence of the spore-forming microbe on the parietal microflora of the large intestine of the animals was shown. Reliable data on the changes in the number of microorganisms (CFU/ml) per 1 cm of the surface of the large intestine were established. As markers making it possible to evaluate the action of biotherapeutic and other medicinal remedies, easily determinable ratios of lac+/lac- of bacteria and Staphylococcus aureus/Staphylococcus spp. was proposed.     

Corynebacterium diphtheriae nontoxigenic strain carrying the gene of diphtheria toxin

Among 828 C. diphtheriae nontoxigenic cultures isolated in different region of Russia in 1994-2002, 114 cultures (13.8%) had the gene of diphtheria toxin (gene tox) and were thus called nontoxigenic tox-carrying (NTTC) strains. All NTTC strains were found to belong to biovar mitis and formed neither normal, nor "defective" diphtheria toxin. The most of NTTC strains (94%) belonged to ribotype "Moskva", not occurring among C. diphtheriae toxigenic strains. The incapacity of NNTC strains of forming diphtheria toxin was caused by mutation: the deletion of one nucleotide which led to the shift of the open reading frame and to the formation of the stop codon. The results of these studies are indicative of the fact that a sufficiently homogeneous and isolated group of C. diphtheriae nontoxigenic strains is spread in Russia. These strains carry the nonexpressing gene of diphtheria toxin and are of no epidemic importance in diphtheria infection.     

New recombinant variant of human immunodeficiency virus of type 1, subtype envB/envA, isolated in Novosibirsk

The nucleotide sequence of the variant of human immunodeficiency virus of type 1 (HIV-1), mostly widespread on the territory of the Novosibirsk region, was determined. The analysis of the nucleotide sequence confirmed that this variant belonged to HIV-1 of subtype A. The HIV-1 recombinant variant of subtype envB/envA with the recombination area within the second conservative region C2 of gene env, so far unknown, was detected and characterized. In HIV-1 the area at the beginning of gene env (5'-env) was found to belong to subtype B and the sequence at the end of gene env (3'-env), to subtype A. The analysis of the amino acid sequence of the third variable region of gene env demonstrated that the viruses under study belonged to macrophagotropic "slow/low" variants, characterized by low replication speed. The analysis of nucleotide sequences of the isolated variants of HIV-1 revealed their close genetic relationship with HIV-1 isolates circulating on the territory of Ukraine.