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.

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.

[Indentification of staphylococci of hospital origin. I. Specific identification of staphylococci]. / Materialy po identifikatsii stafilokokkov gospital'nogo proiskhozhdeniia. Soobshchenie I. Vidovaia identifikatsiia stafilokokkov

In 22 biological tests a study was made of the properties of 1117 strains of staphylococci isolated from patients and medical personnel surgical departments. The significance of each of the tests for species identification of staphylococci was assessed on the basis of correlation of its results with the results of study of 3 main signs characteristic of S. aureus: the presence of coagulase, anaerobic mannite fermentation, and of DNA-ase. Besides the ones pointed out the following could be considered as properties characteristic of S. aureus: flocculus-forming factor, fibrinolysin, hyaluronidase, lysozyme, golden pigment, tellurite-reductase, aerobic fermentation of mannite and tregalose. A standard system of species identification of staphylococci was elaborated; on its basis assessment was made of the diagnostic value of a number of simple systems used in practice for determination of staphylococcus species.

[Data on the identification of staphylococci of hospital origin. Report 2. Method of biological typing of S. epidermis]. / Materialy po identifikatsii stafilokokkov gospital'nogo proiskhozhdeniia. Soobshchenie 2. Metod biologicheskogo tipirovaniia S. epidermis

In accordance with the principles of numerical taxonomy the authors elaborated a new method of biological typing of S. epidermidis strains of hospital origin based on the use of 5 tests (gelatinase, hemolysis, lecithinase, phosphatase, lysozyme). The suggested scheme includes 5 biotypes. In typing 690 S. epidermidis strains it was revealed that 47.5% belonged to biotype 1,14.4% - to type 2,11.2% - to type 3,7.7% - to type 4,14.5% - to type 5, and 4.7% were nontyping strains. The suggested scheme permitted better differentiation of the cultures under study than methods of biological typing suggested earlier by foreign authors. The new scheme requires wide approbation.

[Resistance of different strains of pathogenic staphylococcus to unfavorable environmental factors]. / Ob ustoichivosti razlichnykh shtammov patogennogo stafilokokka k neblagopriianym vneshnim faktoram

A study was made of the resistance to drying the UV-irradiation, the action of furacillin and chloramine displayed by 60 stains of S. aureus differing by origin (hospital and extrahospital), by the source of discharge (the upper respiratory tracts of carriers and the discharge of the purulent-inflammatory foci of surgical patients), relation to the antibiotics (polyresistant and sensitive) and phage-group reference. It was found that the resistance of staphylococci to the unfavourable factors was not always associated with the listed signs of the strains. In respect to drying a marked resistance was expressed by the hospital strains in comparison with the extrahospital ones, polyresistant in comparison with the sensitive ones, staphylococci of III and I+III phage groups in comparison with the strains of other bacteriophage groups. Strains of the III phage group proved to be the most resistant to the UV-irradiation. Strains isolated from carriers were more resistant to furacillin than staphylococci isolated from the purulent-inflammatory foci. Strains of the III phage group and nontyping had analogous advantages over the cultures of other phage groups.

[Virulence of Pseudomonas aeruginosa]. / Nekotorye dannye o virulentnosti Pseudomonas aeruginosa

A study was made of the virulence of 137 strains of P. aeruginosa on a model of intraperitoneal infection of albino mice. The graded index of the 1/T effect (the value reverse to the time of mouse death, in days) was in direct relationship to the log of the culture dose. The optimal infective dose in tesing the strain virulence was a dose equal to 10-8-5 microbial cells. The virulence index V was a satisfactory index characterizing the strain virulence in the selected model of infection. V values of the strains studied were subject to the law of normal distribution. P. aeruginosa virulence failed to depend on the periods of strain storage (museum and freshly isolated) their origin (from man or animals) and the source of isolation (different localization of diseases in man).

[Quantitative indices of lysozyme activity in staphylococci]. / Kolichestvennye pokazateli lizotsimnoi aktivnosti stafilokokkov

The lysozyme activity of 354 lysozyme-positive and 100 lysozyme-negative (by the results of qualitative test) staphylococcus strains were studied quantitatively. The method was based on titration of the lysozyme in the culture fluid of 48-hour broth cultures of the strains under study. The quantitative method proved to be more sensitive than the qualitative one, and permitted to reveal the lysozyme production in 71% of the strains which were formerly considered to be lysozyme-negative. There were distinct species differences between the lysozyme-positive staphylococci: the mean lysozyme level in the S. aureus was significantly greater then in the S. epidermis. There was no regular association between the lysozyme activity, staphylococcus origin, bacteriophage reference and the antibiotic resistance.

[Changes in the humoral response to sheep erythrocytes based on data from a determination of the level and classes of antibodies in mice immunized with purified staphylococcal anatoxin]. / Izmenenie gumoral'nogo otveta na éritrotsitov barana po dannym opredeleniia urovnia i klassov antitel u myshei, immunizirovannykh anatoksinom stafilokokkovym ochishchennym.

The intensity and direction of the modulation of humoral immune response, induced by the action of purified staphylococcal toxoid (PST), depend on the dose of the preparation, the dose of the test antigen, the scheme of the experiment, the time of the registration of its results and the genotype of animals. PST induces the modulation of the synthesis of both IgM and IgG antibodies. The injection of small divided doses of PST enhances immune response to heterologous antigen, while a single inoculation of the total dose produces no such effect.

[The patterns of the corrective action of a natural immunomodulator on the secondary immunological defect caused by a corpuscular pertussis vaccine]. / Zakonomernosti korrigiruiushchego deistviia prirodnogo immunomoduliatora na vtorichnyi immunologicheskii defekt, vyzvannyi korpuskuliarnoi kokliushnoi vaktsinoi.

Purified staphylococcal toxoid (PST) was shown to be capable of preventing the development of secondary antigen-nonspecific immune deficiency in mice, immunized with whole-cell pertussis vaccine. The immunocorrective action of PST was manifested after its injection before (on day -1), simultaneously with and after (on day +1) the injection of whole-cell pertussis vaccine. Correction was either complete or partial, depending on the scheme of the experiment and the dose of PST.

[The characteristics of the protective and antigenic activities of purified staphylococcal anatoxin in trials with mice of different genotypes]. / Kharakteristika protektivnoi i antigennoi aktivnosti anatoksina stafilokokkovogo ochishchennogo v opytakh na myshakh raznykh genotipov.

The protective potency of purified staphylococcal toxoid by the survival rate of immunized mice challenged with the culture of Staphylococcus aureus strain L-1726 and the antigenic properties of the toxoid, determined by the level of antitoxin in the blood of mice and by the intensity of cell-mediated immunity in the spleen-cell migration inhibition test, were studied. The experiments were made on CBA and C57BL/6 mice. Purified staphylococcal toxoid was shown to possess antigenic and protective properties in a wide range of doses between 0.15 and 15 binding units per mouse. The protective effect of the toxoid in CBA mice was manifested in the presence of circulating antibodies and cell-mediated reaction or only in the presence of the toxoid. In C57BL/6 mice the protective effect of the toxoid was less pronounced and appeared in combination with the induction of cell-mediated immunity in the presence of an extremely low antibody level (0.062 I.U.).

[Patterns in the antigen-nonspecific modulation of the B-cell activity in mice under the influence of a purified staphylococcal anatoxin]. / Zakonomernosti antigennespetsificheskoi moduliatsii aktivnosti B-kletok myshei pod vliianiem ochishchennogo stafilokokkovogo anatoksina.

Purified staphylococcal toxoid (PST) has been shown to be an antigen-nonspecific immunomodulator, capable of inducing changes in the immune response of B-cells to unrelated antigens, such as sheep red blood cells (SRBC), in a wide range of doses (from 15 to 0.15 binding units per mouse). The manifestation of the immunomodulating effect depends on the conditions of the experiment: the doses of PST and SRBC, the age of mice, the sequence of the injections of the antigens and the intervals between the injections. The simultaneous injection of PST and SRBC induces, as a rule, an increase in immune response to the test antigen, while their separate injection induces mainly immunosuppression.

[Clinical study of the efficacy of staphylococcal anatoxin in relation to the phage group to which the staphylococcal strains--the causative agents of infection--belong]. / Klinicheskoe izuchenie éffektivnosti stafilokokkovogo anatoksina v sviazi s fagogruppovoi prinadlezhnost'iu shtammov stafilokokka - vozbuditelei infektsii

In comparing the bacteriophage group reference of the strains of pathogenic staphylococci isolated in case of postoperative complications from children given staphylococcus toxoid for prophylactic purpose and from control group it was found that prophylactic vaccinations of staphylococcus toxoid created the most intense immunity against staphylococci of the I bacteriophage group. There was found no significant association between the efficacy of the therapy and bacteriophage reference of staphylococci--the causative agents of the infection.

[Coagulase-negative staphylococci isolated from patients. II. Species diversity of the strains]. / Koagulazootritsatel'nye stafilokokki, vydelennye ot bol'nykh. Soobshchenie II. Vidovoe raznoobrazie shtammov.

Of 403 coagulase-negative staphylococcal strains isolated from patients with different forms of infection 68,1% of the cultures could be identified in accordance with the scheme proposed by Akatov and Devriese. Of these, S. epidermidis constituted 55.1%, S. saprophyticus 13.5%, S. sciuri, S. warneri, S. cohnii, etc., 0.4% to 5.5%. A small group (8,2%) of novobiocin-resistant S. epidermidis and S. hominis strains was detected. S. epidermidis and S. warneri were isolated mostly in septicemia, conjunctivitis, purulent processes; S. saprophyticus and S. sciuri from infected wounds, nonidentified Staphylococcus spp., group I, in urological diseases. The cultures of S. epidermidis sensu stricto belonged, as a rule, to biotype 1, S. epidermidis according to Baird-Parker, S. hominis and S. stimulans belonged to biotype 4. No strains of biotype 2 were detected.

[The modulation of cellular immunity in vivo and in vitro under the action of purified staphylococcal anatoxin]. / Moduliatsiia kletochnogo immuniteta in vivo i in vitro pod deistviem anatoksina stafilokokkovogo ochishchennogo.

Purified staphylococcal toxoid modulates (mainly suppresses) cell-mediated immune response to heterogeneous antigens of animal origin (to sheep red blood cells as shown by the delayed hypersensitivity reaction) or bacterial origin (to BCG as shown by the splenocyte migration test). The direction and manifestation of modulation depend on the strain of mice, dose of the toxoid, dose and nature of the test antigen and the immunization schedule (intervals between the injections of the antigen).

[Phage typing and lysogen typing of Staphylococcus aureus]. / Fagotipirovanie i lizogenotipirovanie zolotistykh stafilokokkov.

A comparison was made between the results of phage and lysogenic typing of S. aureus strains isolated during several outbreaks of staphylococcal infection and S. aureus cultures isolated from the same carriers at different periods. The study of the groups of strains having the same origin showed that the differences in the number of reactions were more pronounced in lysogenic typing than in phage typing. For this reason lysogenic typing can be recommended only for the identification of those strains which cannot be identified with the use of the phages of the International Basic Set. The results of the experiments with induced phages proliferating in a restriction-defective strain indicated that restriction and modification were mainly responsible for the specificity of lytic reactions.

[Species characteristics of coagulase-negative staphylococci of animal origin]. / Vidovaia kharakteristika koagulazootritsatel'nykh stafilokokkov zhivotnogo proiskhozhdeniia.

The specific identification of 271 strains of coagulase-negative staphylococci isolated from different animals (cows, sheep, swine, hens, monkeys, minks, sables, foxes, etc.) was carried out according to the scheme of Akatov--Devriese. Species could be determined in 77.5% of the strains. The representatives of S. sciuri (55.5%) and S. xylosus (11.4%), very seldom occurring in humans, prevailed among the identified cultures. In 31.4% of coagulase-negative strains of animal origin the presence of protein A was established. The study of the time of glucose fermentation in the cultures and the type of colonies formed on agar with crystalline violet permitted the additional characterization of the majority of the strains of coagulase-negative staphylococci. Only in 4.8% of cases the strains under study could be lyzed by typing phages Holmberg and belonged to 6 phage types; of these, 117 A was the most numerous one (7 out of 13 typed cultures). No relationship between the phage type and the species of the strains was established.

[Comparison of the spectra of membrane proteins in differentiating coagulase-negative staphylococci]. / Sopostavlenie spektrov membrannykh belkov v differentsiatsii koagulazootritsatel'nykh stafilokokkov.

The comparison of the spectra of the membrane proteins of 12 typing strains of coagulase negative staphylococci has revealed differences which probably reflect the distinctive features of membrane proteins, intrinsic to individual bacterial species.

[Induction of delayed hypersensitivity in guinea pigs by staphylococcal cell wall components]. / Induktsiia giperchuvstvitel'nosti zamedlennogo tipa u morskikh svinok komponentami kletochnoi stenik stafilokokka.

The subcutaneous injection of 100 micrograms of staphylococcal cell-wall peptidoglycan in Freund's incomplete adjuvant leads to the development of sensitization which can be detected on days 7-35 by the splenocyte migration inhibition test. Sensitization can be detected with peptidoglycan, as well as with staphylococcal cell walls. Teichoic acids produce no such effect. The sensitization of guinea pigs with whole staphylococcal cells introduced in three injections also leads to the development of delayed hypersensitivity specific to staphylococcal cell walls, peptidoglycan, but not teichoic acids.

[The capacity of purified staphylococcal anatoxin to correct antigen-specific and antigen-nonspecific immunological defects]. / Sposobnost' anatoksina stafilokokkovogo ochishchennogo ispravliat' antigenspetsificheskii i antigennespetsificheskii immunologicheskie defekty.

Purified staphylococcal toxoid is capable of partially preventing the development of antigen-specific (induced by the supraoptimal dose of sheep red blood cells) and antigen-nonspecific (induced by Tahyna virus) defects of humoral immune response, as well as abolishing these defects. The presence and manifestation of the correction of virus-induced immunodeficiency is determined by the dose of the toxoid and the interval between the injections of purified staphylococcal toxoid and the infective agent.

[Antistaphylococcal bacteriostatic activity of the sera from surgical patients]. / Ob antistafilokokkovoi bakteriostaticheskoi aktivnosti syvorotok khirurgicheskikh bol'nykh

Blood serum was examined in 41 patients (operated for various forms of acute appendicitis) on the 5th--6th day after the operation when 10 of the patients developed purulent complications of staphylococcal etiology. A determination was made of the titres of beta-lysins and the bacteriostatic activity against 2 strains of S. aureus by the modified Ehrenkranz et al method. The mentioned indices were low in the great majority of cases; consequently, the appearance of purulent complications in the operated patients was independent of the antistaphylococcal bacteriostatic activity and the beta-lysin titres in their sera. Prophylactic express-immunization of a number of patients by crude staphylococcus toxoid did not influence the nonspecific humoral immunity factors.