[The chemotherapeutic efficacy of ciprofloxacin and lomefloxacin in the inhalation method of infecting white mice with tularemia]. / Khimioterapevticheskaia éffektivnost' tsiprofloksatsina i lomefloksatsina pri ingaliatsionnom sposobe zarazheniia tuliaremiei belykh myshei.

Peculiarities of the protective effect of ciprofloxacin and lomefloxacin were studied and the optimal regimens of their use were determined in multifactor experiments on albino mice infected with finally dispersed aerosol of the virulent strain of the European subspecies of Francisella tularensis. As for protective effect, the fluoroquinolones provided high percentage of the animal survival. The optimal course of the treatment was at least 7 days. The interval of 0 to 48 hours between the infection and the start of the treatment had no statistically significant effect on chemotherapeutic efficacy of fluoroquinolones.

[Protective properties of doxycycline, rifampicin and sisomycin in experimental pulmonary tularemia of albino mice]. / Zashchitnye svoistva doksitsiklina, rifampitsina i sizomitsina pri éksperimental'noi legochnoi tuliaremii belykh myshei.

The protective effects of doxycycline, rifampicin and sisomicin were compared in a multifactor experiment with animal infection induced by finally dispersed aerosol of a virulent strain of the European variant of the tularemia causative agent and the optimal regimens for the antibiotic use were determined. By the values of the protective effect rifampicin and sisomicin were shown to provide a high percentage of the animal survival: more than 80 and up to 50-70 per cent of the animals survived when the aerosol infective doses were 100 and 10,000 LD50, respectively. A characteristic feature of doxycycline was its activity only in the infection induced by low doses of the biological agent. The optimal course of the antibiotic therapy in inhalation tularemia was 6 to 8 days. The interval of 1 to 3 days between the infection and the therapy start had no significant effect on the protective efficacies of the antibiotics.

[Comparative evaluation of the effectiveness of fluoroquinolones in experimental anthrax infection]. / Sravnitel'naia otsenka éffektivnosti ftorkhinolonov pri éksperimental'noi sibireiazvennoi infektsii.

Comparative antibacterial activity and protective efficacy of ciprofloxacin, pefloxacin and lomefloxacin were estimated in a model of anthrax. The MICs of the three drugs determined by the method of serial dilutions for three vaccinal strains of Bacillus anthracis were 0.5 to 1.0 microgram/ml. The protective efficacy of the chemotherapeutics in experimental anthrax induced by the spores of the vaccinal strain 71/12, Tsenkovsky was evaluated in mathematically designed four-factor experiments. It depended on the infective dose and the chemotherapy term and amounted in the protective use of the drugs in the daily doses, equivalent to those for humans, to 80-100-percent protection of the animals infected with 10 LD50 of the biological agent, to 50-80-percent protection with the use of 100 LD50, to 40-70-percent protection with the use of 1000 LD50 and to 50-90-percent protection in the therapeutic use of the fluoroquinolones. This was indicative of the fact that the fluoroquinolones were chemotherapeutically highly active in the treatment of experimental anthrax. The marked therapeutic efficacy of the fluoroquinolones and the high percentage of the animal protection after their urgent prophylactic use in a single dose are their obvious merits. The total values of the protective efficacy of the three fluoroquinolones with respect to anthrax were practically the same.

[Effect of antibiotics on Francisella tularensis]. / Deistvie antibiotikov na Franscisella tularensis.

The minimum inhibitory concentrations of rifampicin, doxycycline, sisomicin, ciprofloxacin and phosmidomycin for various strains of Francisella tularensis were 0.5 to 2.0, 0.5 to 2.0, 0.125 to 0.4, 0.625 to 0.125 and 2.0 to 12.5 micrograms/ml, respectively. Ciprofloxacin and sisomicin had a marked bactericidal effect. The bactericidal effect of rifampicin was insignificant. Doxycycline and phomidomycin had practically no such effect. All the antibiotics had a post effect. The level of the post-antibiotic effect was different and depended on the antibiotic concentration.

[Elaboration of a rapid method of determining the sensitivity of Brucella to antibiotics]. / Razrabotka ékspressnogo metoda opredeleniia antibiotiko- chuvstvitel'nosti brutsell.

Optimal conditions were developed for determination of antibiotic sensitivity in Brucella by using enzyme immunoassay directly in the primary cultures of the material tested. The Brucella concentration in the material tested should be not lower than 1.10(6) microbial cells/ml and the time of culture incubation be 24 hours at 37 degrees C. The obligatory condition is to use a liquid medium, i.e. the Albimi broth with 1% glucose. To inhibit the foreign microflora it is recommended to use polymyxin B and amphoglucamine in a concentration of 3 microgram/ml. The use of enzyme immunoassay was shown that it was possible to determine the antibiotic sensitivity of Brucella in practice.

[Detection of the determinants of tetracycline A, B and C resistance in Shigella and Salmonella using DNA probes]. / Opredelenie determinant resistentnosti k tetratsiklinu klassov A, B i C u shigell i sal'monell s pomoshch'iu DNK-zondov.

Genetic determinants of tetracycline resistance of classes A, B and C were detected with DNA probes labeled with radioactive phosphorus (32P) in Shigella (44 strains) and Salmonella (50 strains). It was shown that in the Shigella strains the frequency of the Tet A gene amounted to 66 per cent, the frequency of the Tet B gene was equal to 84 per cent, the frequency of their combination was equal to 50 per cent and the frequency of the Tet C gene was nil. In the Salmonella strains the frequency of the Tet A, Tet B and Tet C genes was equal to 0.100 and 20 per cent, respectively, and that of their combination amounted to 20%. Possible use of the DNA probes in epidemiological analysis of outbreaks of Shigella and Salmonella infections is suggested.

[Sensitivity of antibiotic-resistant strains of Salmonella to new antibiotics and chemotherapeutic agents]. / Chuvstvitel'nost' antibiotikoustoichivykh shtammov Sal'monell k novym antibiotikam i khimiopreparatam.

One hundred and sixty two antibiotic resistant strains of Salmonella isolated within 1984-1988 in Leningrad and the Leningrad Region were tested with respect to their sensitivity to new antibiotics and chemotherapeutics developed or being developed in the USSR. At the background of high numbers of circulating Salmonella strains resistant to the routinely used antibiotics such as doxycycline, streptomycin and gentamicin they appeared to be highly sensitive to amikacin, ciprofloxacin, pefloxacin and the 3rd generation cephalosporins i.e. ceftazidime and cefotaxime as well as to thienamycin. These modern antibacterial agents are possibly to be the drugs of choice in etiotropic treatment and chemoprophylaxis of septic acute intestinal infections due to Salmonella strains with multiple resistance. Resistance of individual Salmonella strains to cefotaxime and ceftazidime indicated that it was possible to use their property for additional labeling of the pathogens within a serological type of Salmonella while conducting epidemiological examinations during outbreaks of acute intestinal infections of Salmonella etiology.

[A rapid immunofluorescent method of determining the antibiotic sensitivity of brucella]. / Immunofliuorestsentnyi ékspress-metod opredeleniia antibiotikochuvstvitel'nosti brutsell.

Optimal conditions for rapid assay of Brucella antibiotic sensitivity with the immunofluorescent method were developed. With this method high sensitivity of the main Brucella species to tetracycline, doxycycline and rifampicin was confirmed. It was found actually possible to use the immunofluorescent method for rapid assay of Brucella antibiotic sensitivity in practice.

[Methodological characteristics of the use of the immunofluorescence method for the rapid determination of the sensitivity of the anthrax microbe to antibiotics]. / Metodicheskie osobennosti ispol'zovaniia immunofliuorestsentnogo metoda dlia ékspressnogo opredeleniia chuvstvitel'nosti sibireiazvennogo mikroba k antibiotikam.

An immunofluorescent method for rapid assay of antibiotic sensitivity of Bacillus anthracis was tested with the use of virulent strains. It was shown that the immunofluorescent method was applicable for assay of antibiotic sensitivity of Bacillus anthracis immediately upon inoculation of the native matter: soil samples and other materials. Comparison of the results obtained with the method of serial dilutions and the immunofluorescent method showed that the levels of the Bacillus anthracis sensitivity to rifampicin, benzylpenicillin, tetracycline, streptomycin and gentamicin coincided. The immunofluorescent method provided the results on antibiotic sensitivity of Bacillus anthracis 6-8 hours after initiation of the rapid assay, the inoculum size being at least 10(6) spores/ml. Isolation of the causative agent pure cultures was not required. Under laboratory conditions the assay required consideration of the characteristic features of the causative agent and fixation of smear replicates in a mixture of 96 degrees ethyl alcohol and 3 per cent hydrogen peroxide for 30 min. After the assay the panels should be disinfected by immersing for 16-18 hours into 6 per cent hydrogen peroxide supplemented with 0.5 per cent of a detergent.

[New immunofluorescent method for the rapid determination of microbial antibiotic sensitivity]. / Novaia immunofliuorestsentnaia metodika ékspressnogo opredeleniia antibiotikochuvstvitel'nosti mikrobov.

A new procedure for rapid determination of the levels of antibiotic sensitivity in pathogenic microorganisms with the use of fluorescent antibodies is described. The procedure was developed with the use of a model of the vaccinal strains of Bacillus anthracis. It is based on determination of the microbial antibiotic resistance with the method of serial dilutions on solid media. Still, the medium with an antibiotic is inoculated instead of the pathogen with the native material subject to the analysis. The antibiotic effect on the microorganism is estimated with the method of fluorescent antibodies. The replica preparations obtained as a result of the pathogen growth in a mixed culture on nutrient media containing definite concentrations of the antibiotic are examined with the method of luminescence microscopy. The modification of the immunofluorescent procedure for rapid determination of the microbial sensitivity to antibiotics does not require obligatory isolation of the pathogen as a pure culture. This makes the procedure more economic with respect to the time necessary for the analysis. The following conditions for performing rapid analysis with respect to Bacillus anthracis are required: the minimal concentration of the pathogen in the specimen (2.10(5) spores/ml), preliminary thermal treatment of the specimen for destroying the spore microflora, additional cultivation for 6-8 hours at 37 degrees C. The presence of the accompanying sporulating microflora, i.e. common microorganisms present in the atmosphere, soil and open water bodies does not prevent the performance of the analysis.