[The sensitivity of enterobacteria to disinfectants]. / Issledovanie chuvstvitel'nosti énterobakterii k dezinfektantam.

The presence of variants resistant to disinfectants in the natural populations has been established by original methods and with the use of a complex of indices. The occurrence, levels and spectra of acquired resistance depend on the type of a disinfecting agent and the habitat of bacteria. The study substantiates the necessity for surveillance on resistance to disinfectants, carried out with the use of universal methods and indices, available to practical laboratories and based on a more rational approach to the choice of disinfectants.

[Antimicrobial properties of fibrous cellulose and other polymeric materials modified with chlorhexidine]. / Izuchenie antimikrobnykh svoistv voloknistykh tselliuloznykh i drugikh polimernykh materialov, modifitsirovannykh s pomoshch'iu khlorgeksidina.

Since fibrous cellulose and other polymeric materials are widely used as dressings, it was of interest to study the mechanism of the antimicrobial action of the products from such materials physically and chemically modified by chlorhexidine, a broad spectrum antiseptic. As vehicles and prolongation agents the following products were used: dressing gauze and cation exchange derivatives of cellulose and starch i.e. monocarboxycellulose (MCC), phosphate cellulose (PC), carboxymethyl cellulose (CMC), monocarboxyl starch (MCS) and alginic acid (AA), a natural compound. It was shown that chemical attachment of chlorhexidine provided a 2-4-fold increase in the antimicrobial effect of the preparations as compared to the use of physical sorption. The antimicrobial effect of the polymeric form of chlorhexidine based on MCC and PC was much higher than that based on MCC, MCS and AA.

[A comparative analysis of the antibacterial activity of antiseptics and antibiotics on samples of Pseudomonas aeruginosa]. / Sravnitel'nyi analiz antibakterial'noi aktivnosti antiseptikov i antibiotikov na vyborkakh Pseudomonas aeruginosa.

Antibiotic and antiseptic preparations, currently used in medical practice, have been tested on the same P. aeruginosa samples and compared by the amplitude of their minimal inhibiting concentration (MIC) values, determined as the average MIC values for the samples under test, by the proportion of variants resistant to the tested preparations, by the distribution of strains in the resistance spectrum, and by the pace of the increase of resistant variants under natural conditions in 5-10 years. On the basis of the results obtained in this study a conclusion has been made that in some cases of local application antiseptic preparations have advantages over antibiotics, especially in controlling hospital strains of microorganisms. The authors believe that the heterogeneity of microbial populations, as well as the frequency of the appearance of resistant variants and the activity of the mechanisms of their selection in hospitals, is of great importance in the development of new preparations, in the re-evaluation of currently used preparations and in the choice of the optimum preparation in concrete situations.

[Comparative study of the effect of antibiotics and antiseptics on Staphylococcus aureus]. / Sravnitel'noe issledovanie aktivnosti antibiotikov i antiseptikov v otnoshenii Staphylococcus aureus.

The routinely used antibiotics and antiseptics were compared with the same staphylococcal isolates by MIC ranges, the mean MIC for the strains, proportion of the variants resistant to the drugs, distribution of the strains by the resistance spectra and the number increase rate for the resistant variants in natural populations within 5-10-year periods. It was concluded that when used locally the antiseptics had some advantages over the antibiotics especially with respect to hospital strains. The authors believe that in developing new drugs, ++re-estimation of the routinely used ones, choosing the optimal drug for a particular case it is more important to consider the heterogeneity of microbial populations, the frequency of resistant variants and activity of the mechanisms of their selection under hospital conditions.

[Control of microbial contamination of antiseptics and disinfectant solutions]. / Kontrol' za mikrobnoi kontaminatsiei antisepticheskikh i dezinfitsiruiushchikh rastvorov.

Since various species of opportunistic and pathogenic bacteria and fungi are known to be present in working solutions of disinfectants and antiseptics, an original method for the detection of bacterial contamination of these solutions has been developed. This method has been introduced into practical activities of sanitary and epidemiologic stations and hospitals in Byelorussia as the principal element of sanitary inspection of antiseptic and disinfectant utilization.

[An evaluation of the sensitivity to antiseptic preparations of clinical strains of microorganisms in the family Enterobacteriaceae]. / Otsenka chuvstvitel'nosti k antisepticheskim preparatam klinicheskikh shtammov mikroorganizmov semeistva Enterobacteriaceae.

Classical enterobacterial strains are sensitive to the working concentrations of pervomur, dioxydine, resorcinol, sodium sulfacyl, iodopyrone, chlorhexidine and boric acid, resistant to the action of cetyplyridinium chloride, rivanol, roccal and ethonium. In enterobacterial populations strains with acquired resistance to chloramine B, iodopyrone, chlorhexidine and resorcinol are present. Hospital strains of enterobacteria are characterized by higher, in comparison with extrahospital strains, resistance to ethonium, sodium sulfacyl, lodopyrone, chloramine B and resorcinol.

[Antiseptic sensitivity of clinical strains of Pseudomonas aeruginosa]. / Chuvstvitel'nost' k antiseptikam u klinicheskikh shtammov Pseudomonas aeruginosa.

MICs, the frequency of clinical and statistic resistance and the antiseptic activity index were studied in complex on out-of-hospital and hospital ecovars of P. aeruginosa. The forms resistant to a number of antiseptics, i.e. chloramine B, chlorhexidine, decamethoxine and dioxidine whose frequency eventually increased were shown to be widely distributed. The antiseptic sensitivity spectrum was more narrow and more heterogeneous than that of other bacteria, the heterogeneity level being dependent on the antiseptic type and bacterial ecovar. The activity of pervomur, phenol, resorcin and boric acid was higher against the clinical strains of P. aeruginosa while iodopyrin, sulfacetamide sodium and dioxidine were less active. The P. aeruginosa strains had natural resistance to cetylpyridinium chloride, rokkal, ethonium, sodium laurate and laurylsulfate and rivanol. It was recommended to assay antiseptic sensitivity of agents causing purulent inflammatory infections and to control circulation of antiseptic resistant variants of bacteria in hospitals.

[Antiseptic resistance of clinical strains of Staphylococcus aureus]. / Ustoichivost' k antiseptikam klinicheskikh shtammov Staphylococcus aureus.

To evaluate the activity of antiseptics and the sensitivity-resistance of bacteria to antiseptics, a number of characteristics has been used, including the minimum inhibiting concentration for different strains, the frequency of statistical and clinical resistance, the antiseptic activity index. A wide spread of S. aureus strains isolated from patients with hospital infections has been revealed. Differences in the resistance of bacterial strains have been established, depending on the type of the antiseptic and the ecovar of bacteria: among hospital ecovars, resistant strains occur more frequently and can resist a wider range of antibiotics. In staphylococcal hospital ecovars the occurrence and level of resistance to a number of widely used antiseptics increase with time. In connection with a wide spread of staphylococcal hospital strains resistant to antiseptics, measures on the control of the circulation of such strains should be introduced into hospitals, and the data thus obtained should be used for the periodic reevaluation of antiseptics used in medical practice and for the choice of preparations to be used for individual therapeutic and prophylactic antisepsis.

[The intensity and dynamics of the development of immunity in the administration of experimental corpuscular ozena vaccines]. / Napriazhennost' i dinamika razvitiia immuniteta pri vvedenii éksperimental'nykh ozenoznykh korpuskuliarnykh vaktsin.

Experiments on the active protection of mice from ozenous infection in its two forms, generalized (acute sepsis) and local (plantar infiltration), have demonstrated that immunity, induced by experimental heat-killed ozena vaccine (Klebsiella ozaenae strain 2211, antigens 02B:K4) introduced in a single injection, is characterized by sufficiently high intensity (the degree of protection increases up to 10,000-fold) and duration (at least 30 days). In both forms the development of immunity is characterized by a rapid rise of its intensity to the maximum level (achieved by the end of week 1), subsequent decrease by weeks 3-4 and disappearance by days 50-60 after immunization. Immunity becomes more intense with the increase of the number of injections if these injections are separated by sufficient intervals (up to 14 days). The optimum schedule used in the study of postvaccinal immunity to experimental generalized and local ozenous infection consists of the subcutaneous injection of K. ozaenae strain 2211 in a dose of 250-500 million microbial bodies per mouse with the subsequent challenge with the virulent strain on week 2 from the date of immunization.

[Immunogenicity of inactivated Klebsiella ozaenae cultures in relation to the properties and methods of culturing and preserving the initial strains]. / Immunogennost' inaktivirovannykh kul'tur Klebsiella ozaenae v zavisimosti ot svoistv, metodov kul'tivirovaniia i khraneniia iskhodnykh shtammov.

Experiments in the active protection of mice from generalized K. ozaenae infection have demonstrated that the heat-killed cultures of K. ozaenae capsular strains (antigens 02B : K4) possess pronounced and stable immunogenic properties, dependent on the presence and type of the capsular antigen and independent of the virulence and age of the initial strain, as well as the time and methods of its cultivation (the type of the culture medium: nutrient agar, glucose-mineral medium) and storage (the term of observation is 2 years). This investigation has resulted in the determination of the strain (2211) with the highest and most stable protective properties and in the selection of the optimum conditions for the immunization of mice (by the subcutaneous injection of 250 microbial bodies per mouse) with its heat-killed culture.

[Antibiotic resistance of enterobacteria isolated from chronic bronchitis and pneumonia patients]. / Ustoichivost' k antibiotikam énterobakterii, vydelennykh ot bol'nykh khronichesmimi bronkhitami i pnevmoniiami.

Resistance of 1060 Enterobacteria strains isolated from patients with chronic pneumonia and bronchitis was studied with respect to 15--18 antibiotics. The methods of agar dilution and sensitivity discs (Pr. mirabilis) were used. High resistance of the isolates to the antibiotics except aminoglycosides was shown. The rate, spectrum and level of the resistance were variable and changed depending on the bacterial species and drug type. The majority (77.7--100 per cent) was multiple resistant (to at least 6--10 antibiotics). The Enterobacteria populations of the respiratory origin were heterogeneous with respect to the resistance warts (61.5--85.7 per cent). The changes included elimination of the primary warts, appearance of new secondary warts or complete replacement of the variant composition. Rational therapy requires investigation of both the species and the variant composition of the microbiocenoses of the bronchial contents and their changes during the patient treatment in the hospital.

[Interpopulation variability of Staphylococcus aureus]. / Mezhpopuliatsionnaia izmenchivost' Staphylococcus aureus.

The comparative study of 830 hospital and 181 extrahospital S. aureus strains has revealed the existance of the interpopulation (group, geographic) variability of this species. Hospital strains differ from those inhabiting other places by the composition of phago- and resistovars, greater resistance to antibiotics, antiseptic and disinfecting agents, the inhibiting action of antagonist, as well as by pronounced antagonistic activity. The biological characteristics of such strains allow one to classify them with the hospital ecological variants (ecovars) of S. aureus. These properties of hospital strains give them selective advantages in hospitals over extrahospital strains, and the latter are thus ousted from the skin surface, mucous membranes, wound surfaces. The measures taken to prevent hospital infections must be aimed mainly against the hospital ecovars of these bacteria.