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O A Dmitrenko

Publications and source records attributed to O A Dmitrenko.

At least 19 recordsLinked to original sources
PubMed1997

[A system of step-by-step differentiation of methicillin-resistant Staphylococcus aureus].

One hundred and eighty four strains of methicillin resistant Staphylococcus aureus (MRSA) isolated in pyosurgical and burn departments of Moscow, Minsk, Omsk, Tbilisi, Vologda, Smolensk and Dushanbe were differentiated with using phages of the International Set (BIS), two collections of experimental phages and two-probe fingerprinting. More than 50 per cent of the isolates could not be typed by the BIS phages. The Experimental Collection of the N.F. Gamaleya Research Institute of Epidemiology and Microbiology (Moscow) was more useful in the differentiation in comparison to the Experimental Collection of the London Health Centre. A new approach applied by us to the establishment of our collection i.e. screening of cultures with a definite specificity of the system of the restriction-modification (by a modified phage 85) followed by their differentiation with respect to the specificity of the prophages (by the induced phages with the respective modification specificity) provided reliable and reproducible results. Our collection made it possible to classify the phage type 85 strains which as was confirmed by the fingerprinting data belonged to 3 different genotype variants. The fingerprinting had no advantages over the typing by the phages of the more extended phage set and was recommended for differentiation of the strains (14 per cent) not sensitive to the phages used. A step-by-step scheme for typing MRSA easy for use in clinical and epidemiological laboratories is described.

Bacteriophage Typing↗
PubMed1994

[Additional differentiation of methicillin resistant strains of Staphylococcus aureus typed by the international phage bank].

In the methicillin resistant strains of Staphylococcus aureus (MRSA) typed by the International Set phages the host specificity of the restriction-modification of the phage 85 DNA was determined, the finger printing of the cell DNA was carried out with using two probes and the lytic spectrum of the phages induced in them was studied. Four clones with different specificity of the restriction-modification system (rm89, rm108, rm121 and rm947) differing from that of strain PS 85 which is the host of phage 85 were detected. The strains belonging to the modification types m89, m108 and m121 contained prophages (within the respective groups) with similar lytic spectra when tested with the use of the PS strains of the International Collection and had cross antiphage immunity. Six phage variants were detected among the phages induced in the strains with the modification type m947 which could be indicative of the clone heterogeneity.

Bacteriophage Typing↗
PubMed1994

[Experimental substantiation of population heterogeneity in methicillin resistant Staphylococcus aureus].

A comprehensive intraspecies typing of the cultures of MRSA collected during inspection of drug resistance in causative agents of intrahospital infections was performed. The following parameters were investigated: antibiotic resistance, toxin production, sensitivity to the phages of the International Set and the phages of an experimental collection providing the isolation of strains with definite specificity of the restriction-modification system. Different clones of methicillin resistant S. aureus were found to be circulating on the territory of the CIS.

Bacterial Typing Techniques↗
PubMed1992

[Phage-mediated conjugative transfer of plasmids in Staphylococcus aureus].

It was shown possible to transfer nonconjugative plasmids during joint cultivation of the donor and recipient cells by transduction and phage-mediated conjugation. In the latter case it was necessary that the phage in the medium was free and the prophage was present in the recipient cells. Differences in the regularities of the transfer of the nonconjugative plasmids mobilized by the conjugative plasmid or phage were observed.

Calcium Chloride↗
PubMed1991

A new approach to establishing the set of phages for typing methicillin-resistant Staphylococcus aureus.

A new approach to using experimental phages for typing methicillin-resistant S. aureus (MRSA) non-sensitive to the phages of International Basic Set (IBS) is described. The collection Includes phage 85, modified on a culture of MRSA, and 5 phages induced from MRSA strains isolated in clinics of Moscow in 1975-76. Firstly, the modified phage selects cultures according to the specific character of its restriction-modification system, then the induced phages differentiate the selected strains into 5 groups (1, 2, 3, 4, 5) based on the specificity of the prophages they contain. Group 1 strains can further be differentiated into 5 subgroups (A, B, C, D, E) by additional phages. Forty-one MRSA strains isolated in 1987-90 in various hospitals of Moscow showing no sensitivity to IBS phages, were lysed by the modified phage, 15 of them belonging to Group 2 and isolated in the traumatological hospital, 26 belonging to Group 1 and were circulating in the burn center. Twenty-three strains of Group 1 appertain to subgroup 1B and were isolated over a 4-year period from the burned surface of patients and from the throat of a medical staff carrier.

Bacteriophage Typing↗
PubMed1991

Lysogeny of methicillin-resistant Staphylococcus aureus and the role of prophages in transfer of conjugative and non-conjugative plasmids.

The lysogenicity of 49 strains of methicillin-resistant S. aureus (MRSA) isolated in Moscow clinics in the 1970s and '80s was studied by the method of mitomycin C induction. It was found that one strain had phage of serogroup B, 33 strains had serogroup F phages and 15 strains had phages of both serogroups. In the course of genetic crossing on nitrocellulose filters it was demonstrated that serogroups B and F prophages contained in recipient cells 1) increase the frequency of transfer of conjugative plasmid pG873 and 2) mobilize transfer of non-conjugative plasmids pE994 and rms7.

Conjugation, Genetic↗
PubMed1991

[Effect of prophages on transfer frequency of conjugative plasmid G 873].

Transfer of the conjugative plasmid G873 on filters and mixed cultivation of the donor and recipient cells in liquid media is described. In the both systems the use of the lysogenic recipient cells (phages of serogroups B and F) in the crossings increased mor than 100-fold the frequency of plasmid transfer. The conjugative transfer of the plasmid in the mixed cultivation system was proved. The conjugative transfer required the presence (while not obligatory) of calcium chloride and was restricted by the serum factors.

Animals↗
PubMed1988

[Experimental phages for differentiating nontypable methicillin-resistant Staphylococcus aureus].

The possibility of using phages, isolated from the lysogenic cultures of methicillin-resistant staphylococci and modified in methicillin-resistant cultures of phage 85, for the differentiation of nontypable staphylococcal strains has been studied. The variants of phage 85 cannot be used for the determination of differences between the strains of methicillin-resistant cultures; they are not suited for typing. For this purpose the collection of phages isolated from lysogenic methicillin-resistant cultures should be used.

Bacteriophage Typing↗
PubMed1984

[Effect of interferon type I on staphylococcal persistence and indices of body immunoreactivity].

After the subcutaneous injection of type I (alpha) interferon into mice their survival rate in staphylococcal infection greatly increased. At the same time duration of staphylococcal persistence in these animals and the number of persisting staphylococci were found to decrease. After the injection of interferon the splenocytes of the treated animals showed a higher capacity for interferon production. During the whole experiment the characteristics of delayed hypersensitivity in these animals showed a tendency towards normalization in comparison with those in infected mice receiving no interferon.

Animals↗
PubMed1982

[Antistaphylococcal activity in interferon preparations].

Antistaphylococcal bacteriostatic and bactericidal activity was detected in the preparations of human leucocytic interferon of the native type. Such an activity could not be neutralized by the interferon antibodies. However, it was usually lost during the process of interferon purification. It is concluded that this antistaphylococcal activity is not related to interferon and is due to other factors which can be isolated with induced leucocytes.

Animals↗
PubMed1978

[Drug resistance stability in staphylococci under different conditions. The mechanism of the recovery of streptomycin sensitivity of a staphylococcal population in patients 7 months after hospital discharge].

A method for analysis of antibiotic sensitivity restoration in staphylococcal populations in humans is described. The mechanism of streptomycin sensitivity restoration in staphylococcal populations on the nasal mucosa of 59 patients 7 months after discharging from surgical stationary was studied. Quantitative estimates for loss of superinfecting streptomycin-resistant staphylococci, initial streptomycin-resistant staphylococci and resistance determinants by the initial streptomycin-resistant staphylococci are presented.

Drug Resistance, Microbial↗
PubMed1978

[Stability of drug resistance in staphylococci under various conditions and the effect on it of prolonged culture storage on artificial nutrient media].

The literature and experimental data on stability of resistance ot benzylpenicillin, streptomycin, tetracycline, chloramphenicol, erythromycin, kanamycin and methicillin in staphylococci stored for prolonged periods of time on artificial nutrient media were systematized. When the staphylococcal cultures were not in contact iwth the antibiotics for 5 to 18 months, sensitive cells to separate drugs were detected in 51.0--67.4 per cent of the strains. The number of such cells in the populations of some strains ranged from 1 to 100.0 per cent. The effect of the resistance multiplicity on the stability of resistance to benzylpenicillin, tetracycline, chloramphenicol and erythromycin was not observed.

Anti-Bacterial Agents↗
PubMedDate not supplied

[A new collection of phages for typing methicillin resistant Staphylococcus aureus].

A new collection of phages for typing methicillin-resistant S. aureus (MRSA) is proposed. The collection includes phage 85 (modified by the MRSA strain), capable of selecting strains with the similar specificity of the restriction-modification system, and 9 MRSA-induced phages. The latter differentiate MRSA strains according to the specificity of prophages present in bacterial cells. The use of this phage collection has permitted the typing of MRSA strains insensitive to the phages of the international collection. Among these cultures an epidemic strain has been detected and the source of its spread in the burn center has been established.

Bacteriophage Typing↗
PubMedDate not supplied

[Conjugative plasmid transfer in Staphylococcus aureus?].

The microbiological and electron-microscopic study of the transfer of conjugative (pG873) and nonconjugative (rms7 and pE994) plasmids in two systems, on nitrocellulose filters and in a fluid culture medium, was carried out. In both systems the low frequency of the transfer of plasmid pG873 or the absence of the transfer of plasmids rms7 and pE994 were observed when nonlysogenic recipients were used for crossing. The presence of prophage in recipient cells increased the rate of the detection of gentamicin-sensitive transconjugants 100-fold and provided to reveal the transfer rms7 and pE994 plasmids. The electron-microscopic study of specimens with lysogenic recipients revealed a picture which can be interpreted as the fusion of two cells. Such picture was not observed in crossings with a nonlysogenic recipient and in preparations obtained from separate donor and recipient cultures.

Collodion↗