[Antibiotic resistance of Shigella isolated in the Kara-Kalpak A.S.S.R. 1987-1988]. / Antibiotikochuvstvitel'nost' shigell, vydelennykh v Karakalpakskoi ASSR v 1987-1988 gg.

Sensitivity of Shigella spp. isolated in one of the hospitals of Nukus within 1987-1988 and earlier in 1977 and 1985 was studied. S. flexneri 1-5 remained the main causative agents of dysentery on the territory. However, beginning from 1987 there were registered cases of dysentery caused by S. dysenteriae 1. The isolates were most sensitive to cefotaxime, cephaloridine, polymyxin B and gentamicin. The majority of the isolates were resistant to tetracycline, levomycetin (chloramphenicol) and streptomycin. No significant changes in the sensitivity levels of the strains isolated in 1987-1988 as compared to those isolated in 1985 were observed.

[Antibiotic sensitivity of Vibrio parahaemolyticus isolated in the Turkmene SSR]. / Chuvstvitel'nost' k antibiotikam paragemoliticheskikh vibrionov, vydelennykh na territorii Turkmenskoi SSR.

Sensitivity of 82 cultures of parahemolytic vibrios to 8 antibiotics was studied. It was shown that the majority of the strains were highly sensitive to levomycetin and gentamicin, sensitive to tetracycline, rifampicin, streptomycin, neomycin and kanamycin and resistant to ampicillin.

[Determining the sensitivity of Pseudomonas to chemotherapeutic preparations by the micromethod in liquid synthetic medium]. / Opredelenie chuvstvite'lnosti pseudomonad k khimioterapevti- cheskim preparatam mikrometodom v zhidkoi sinteticheskoi srede.

Ever increasing interest is being displayed lately to simple, economic and standard systems for assay of antibiotic sensitivity of microbes with microtechniques in nutrient media requiring no raw materials in short supply. For determining sensitivity of Pseudomonas spp. to chemotherapeutics a liquid synthetic medium balanced by its cationic composition and containing no competing agents of sulfanylamides was used. Three procedures were comparatively estimated: the method of serial dilutions in the liquid medium with using immunological trays, the method of serial dilutions in agar and the diffusion test. In the estimation 185 strains of various Pseudomonas species were used: P. aeruginosa, P. cepacia, P. fluorescens, P. stutzeri, P. putida and P. pseudomallei. The method using the liquid synthetic medium and trays provided more precise interpretation of the results of the assay of the Pseudomonas spp. sensitivity to aminoglycosides, tetracycline, polymyxin and sulfamonomethoxine that the routine procedures. It showed some other advantages such as simplicity, low cost, low medium requirement and glassware economy. The application of the method allowed to exclude the use of expensive imported nutrient media in assay of sulfanylamide sensitivity.

[Determination of the sensitivity of Pseudomonas aeruginosa to antibiotics using a synthetic liquid culture medium]. / Opredelenie chuvstvitel'nosti Pseudomonas aeruginosa k antibiotikam v zhidkoi sinteticheskoi pitatel'noi srede.

Antibiotic sensitivities of 120 Ps. aeruginosa strains isolated from patients and environmental objects have been studied by microdilutions in modified Jorgensen's liquid synthetic nutrient medium. Use of "transitional" concentrations of antibiotics permits a simultaneous examination of the sensitivities of 7-8 Ps. aeruginosa cultures to 6-11 antibiotics. The simplicity, low price, low consumption of nutrient medium, sufficient accuracy and good reproducibility of the results recommend this method for laboratory practice.

[Changes in the degree of sensitivity to antibiotics of Shigella isolated from patients with dysentery in a city infectious disease hospital over the past 8 years]. / Izmeneniia za 8 let v urovne chuvstvitel'nosti k antibiotikam shigell, vydelennykh ot bol'nykh dizenteriei v gorodskoi infektsionnoi bol'nitse.

Changes in sensitivity of Shigella and in particular Shigella flexneri isolated from dysentery patients in a city infection hospital within 8 years i.e. from 1977 to 1985 were followed. It was shown that the changes were to the greater extent connected with preferable use of certain antibiotics in the hospital.

[Comparative evaluation of 2 methods--dilution in agar and diffusion in agar--in determining Pseudomonas aeruginosa sensitivity to antibiotics]. / Sravnitel'naia otsenka dvukh metodov--razvedenii v agare i diffuzii v agar--pri opredelenii chuvstvitel'nosti Pseudomonas aeruginosa k nekotorym antibiotikam.

Sensitivity of 200 strains of Pseudomonas aeruginosa to 8 antibiotics was studied with 2 methods, agar dilution and agar diffusion. The data obtained with the two methods were in good agreement. The simple method of agar diffusion provided sufficiently precise results in determination of the Pseudomonas sensitivity to carbenicillin and polymyxin. With the use of the correction principle by the "mobile intermediate zone" it also provided sufficiently precise results in determination of the Pseudomonas sensitivity to gentamicin. The necessity of using the reference strain ATCC 27853 of P. aeruginosa in every experiment is stressed. The peculiarities of the data interpretation in determination of antibiotic sensitivity of Pseudomonas are discussed.

[Tolerance of group A streptococci to the bactericidal effect of various antibiotics]. / Izuchenie tolerantnosti streptokokkov gruppy A k bakteritsidnomu deistviiu nekotorykh antibiotikov.

The MICs and MBCs (minimum bactericidal concentration) of 6 antibiotics (benzylpenicillin, oxacillin, cephalothin, ristomycin, erythromycin and lincomycin) for 50 strains of group A streptococci were determined with serial dilutions in a liquid medium (the medium for isolation of streptococci of the I. I. Mechnikov Moscow Research Institute of Vaccines and Sera) followed by volumetric platings on a solid medium (the same medium supplemented with 1.5 per cent agar). The results are discussed in relation to the problem of Streptococci tolerance to the bactericidal effect of the antibiotics.

[Sensitivity of 56 strains of Streptococcus group B to 12 antibiotics: its determination by dilution and diffusion in agar]. / Chuvstvitel'nost' k 12 antibiotikam 56 shtammov streptokokkov gruppy B: opredelenie metodami razvedeniia v agare i diffuzii v agar.

Sensitivity of 56 streptococcal strains of group B to 12 antibiotics was studied with the method of dilution in a special solid medium for cultivation of streptococci and with the method of agar diffusion in the same medium. All the strains were found to be sensitive to chloramphenicol, ristomycin and erythromycin. The predominating majority of the strains were sensitive to beta-lactam antibiotics and lincomycin. All the strains were resistant to aminoglycoside antibiotics, such as streptomycin and gentamicin. More than 85 per cent of the strains were resistant to tetracycline. Strains with multiple resistance to 2-7 antibiotics were detected. Satisfactory correlation between the two methods was observed. It was shown to be clinically advisable to determine the sensitivity of streptococci of group B to beta-lactam antibiotics, erythromycin and lincomycin.

[A method of diffusion in agar for determining streptococcal sensitivity to antibiotics]. / Metod diffuzii v agar dlia opredeleniia chuvstvitel'nosti streptokokkov k antibiotikam.

An agar diffusion method for determination of antibiotic sensitivity to streptococci of different serological groups with semiquantitative estimation of the results was developed with the use of the dry nutrient medium of the I. I. Mechnikov Central Research Institute of Vaccines and Sera for isolation of hemocultures and cultivation of streptococci. The addition of blood or serum to this medium is not required. The standard inoculum (2 milliard microbial bodies) is added into the depth of the nutrient agar thus providing the optimal conditions for the growth of the facultative anaerobes. The MICs of the antibiotics and the diameters of the growth inhibition zones of 150 streptococcal strains were compared and an estimation table for interpretation of the data of the agar diffusion test was presented. This simple method provides a sufficient accuracy and satisfactory reproducibility in the clinical tests.

[Introduction of the inoculum into the upper agar layer as an alternative method in determining microorganism sensitivity to antibiotics by diffusion in agar]. / Vnesenie inokuliata v verkhnii sloi agara kak al'ternativnyi sposob pri opredelenii chuvstvitel'nosti mikroorganizmov k antibotikam metodom diffuzii v agar.

A procedure for addition of the inoculum to the surface layer of semisynthetic agar was developed and recommended for the use in the assay of antibiotic sensitivity of microorganisms. The procedure differs from the alternative method of Barry et al. It is of special value when it is necessary to determine antibiotic sensitivity of the pathogens of highly contagious infections with the agar diffusion method.

[Antibiotic sensitivity of beta-hemolytic Streptococcus group A on a new nutrient medium for the cultivation of streptococci]. / Izuchenie chuvstvitel'nosti k antibiotikam beta-gemoliticheskikh streptokokkov gruppy A na novoi pitatel'noi srede dlia kul'tivirovaniia streptokokkov.

Sensitivity of 167 strains of beta-hemolytic streptococci of group A was studied with the method of serial dilutions on a solid agar medium for cultivation of streptococci. The medium was developed at the I. I. Mechnikov Research Institute of Vaccines and Sera. It does not require addition of blood or serum. The strains were found to be highly sensitive to penicillin, cephalothin and erythromycin. The number of the strains resistant to tetracycline, streptomycin, gentamycin, levomycetin (chloramphenicol) and ristomycin amounted to 51, 36, 23, 1.8 and 1.8 per cent, respectively. One of the strains (0.6 per cent) was resistant to lincomycin. Strains with multiple resistance were isolated. The necessity of regular control of distribution of antibiotic resistance among staphylococci is indicated.

[Determination of the sensitivity of NAG-Vibrio to antibiotics by the methods of serial dilution in agar and agar diffusion]. / Opredelenie chuvstvitel'nosti NAG-Vibrionov k antibiotikam metodami seriinykh razvedenii v agare i diffuzii v agar.

The methods of serial dilutions and agar diffusion in medium AGV were used in the study on sensitivity of 200 NAG-vibrio strains to 10 antibiotics. The regression equations showing the relation between the MIC log2 and the diameter of the zones of the vibrio growth inhibition around the standard discs with the antibiotics were estimated. An evaluation table was developed for semiquantitative interpretation of the diameters of the inhibition zones of the vibrio growth when the agar diffusion method was used. A possibility of rapid estimation of the results in determination of the vibrio sensitivity to antibiotics with the methods of serial dilutions and agar diffusion is shown.

[Combination of antibiotics and sodium nucleinate in the therapy of an experimental mixed infection due to pyogenic bacteria]. / Kombinatsiia antibiotikov i nukleinata natriia v terapii smeshannoi infektsii, vyzvanno7i gnoerodynmy bakteriiami, v éksperimente.

Mice were infected wtih a mixed culture of pathogenic Staphylococcus and Pseudomonas aeruginosa. The doses of sodium nucleinate were titrated. When used for prophylactic and treatment-prophylactic purposes, these doses did not change the antiinfection resistance of the animals. The doses of tetracycline and lincomycin combination (lincotetrin) having no therapeutic effect on repeated use of the combination were also chosen. It was shown that the combined use of the antibiotics and sodium nucleinate in the above doses promoted a significant increase in the animal survival rate while the drugs used alone did not promote any increase in the survival of the mice. The decrease in the death rate of the animals was observed both with the parenteral and the oral use of sodium nucleinate.

[Standardization of the methods for determining microorganism sensitivity to antibiotics. Semiquantitative and quantitative evaluation of the results of the diffusion test]. / Ob unifikatsii metodov opredeleniia chuvstvitel'nosti mikroorganizmov k antibiotikam. Polukolichestvennaia i kolichestvennaia otsenka rezul'tatov diffuzionngo testa.

On the basis of the literature data and experimental findings approaches are proposed for improving the agar diffusion method for determination of microbial sensitivity to antibiotics involving a semiquantitative or quantitative system for interpretation of the diffusion data obtained with the use of a new nutrient medium.

[Significance of determining novobiocin sensitivity in the taxonomy of staphylococci]. / Znachenie opredeleniia chuvstvitel'nosti k novobiotsinu v taksonomii stafilokokkov.

Novobiocin sensitivity of 96 strains belonging to various staphylococcal species was studied. It was noted that Staph. saprophyticus significantly differed from Staph. aureus and Staph. epidermidis with respect to the above antibiotic. The MIC up to 2 micrograms/ml and the growth inhibition zones of 26--35 mm in diameter were characteristic of Staph. aureau and Staph. epidermidis, while the respective figures for most of the strains of Staph. saprophyticus were 32--64 micrograms/ml and 12--17 mm. However, 28 percent of the strains of Staph. saprophyticus did not differ with respect to their movobiocin sensitivity from the other 2 species. It is concluded that the "novobiocin test" may be used for differentiation of staphylococci, within the genera. At the same time it was shown that the method of the paper sensitivity discs compares very favourably with the method of serial dilutions in agar not only because of its simplicity and convenience of manipulation with single strains, but also of the possibility of identifying the population heterogenicity with respect to novobiocin sensitivity.

[Antibiotic sensitivity and the characteristics of transmissive R plasmids in Shigella belonging to various species]. / Chuvstvitel'nost' k antibiotikam i kharakteristika transmissivnykh R-plazmid u shigell razlichnoi vidovoi prinadlezhnosti.

Sensitivity of 241 Shigella strains isolated from patients at various regions of the USSR in 1975--1978 was tested with respect to 14 antibiotics by the method of serial dilutions. 90.5 per cent of the isolates proved to be resistant to the antibacterial drugs and the greater part of 75.9 per cent of them had multiple resistance. The resistance of the Shigella was most pronounced and frequent with respect to tetracycline, streptomycin, levomycetin, as well as ampicillin and carbenicillin. Gentamicin, cephaloridin, polymyxin M, kanamycin, monomycin, neomycin and rifampicin were highly active against the Shigella. More than 50 per cent of the isolates were sensitive to levomycetin, ampicillin and carbenicillin. Differences in the frequency of the resistant strains and the spectrum of the antibiotic resistance of different Shigella subgroups (species) were observed. The study of 173 multiple resistant Shigella strains showed that about 67 per cent of the strains had a capacity for transduction of the resistance markers into the recipient cells of E. coli. The conjugative R-plasmids were most frequent in Sh. boydii and Sh. sonnei (95 and 95 per cent respectively), less frequent in Sh. flexneri and Sh. newcastle (68 and 53 per cent respectively) and least frequent in the mannitol negative Shigella (25 per cent). The capacity for transduction of R-plasmids in the strains carrying the determinants of resistance to 2 or 3 antibiotics was higher than in the strains carrying the determinant of resistance to one antibiotic. The clinical Shigella strains tested mainly had transmissive R-plasmids of fi--character (79 per cent).

[Simple qualitative methods of detecting beta-lactamase-producing strains of microorganisms]. / Prostye kachestvennye metody obnaruzheniia beta-laktamazoprodutsiruiushchikh shatmmov mikroorganizmov.

Modifications of two microbiological qualitative methods for detection of beta-lactamase-producing microbial strains are described. The methods are based on the principle of Goths. One of the methods named "contact" significantly differs from the prototype and is more simple, convenient, easily reproducible and does not require the use of special equipment and special training of the staff.

[Comparative antibiotic sensitivity of different species of staphylococci isolated from humans]. / Sravnitel'naia chuvstvitel'nost' k antibiotikam razlichnykh vidov stafilokokkov, vydelennykh ot liudei

A total of 206 strains of various staphylococcal species isolated from various sources were studied with respect to their sensitivity to 18 antibiotics. The number of strains poly-resistant to the antibiotics was almost the same among Staph. aureus and Staph. epidermidis, i. e. 54.8 and 51.3 per cent respectively. The coagulase-negative and mannitol-negative variants of Staph. aureus and Staph. epidermidis possessing high biological activity (10-14 properties) were resistant to more antibiotics as compared to the low active strains.