Biological properties of sherry yeasts in the presence of antimicrobial preparations

The wine yeasts Cheres were not sensitive to high concentration (500 gamma/ml) of benzylpenicillin, streptomycin, tetracycline, oxytetracycline, chlortetracycline, morphocycline, erythromycin, oleandomycin, monomycin, neomycin, kanamycin, polymyxin, ampicillin, oxacillin, methicillin, ceporin, ristomycin, levomycetin, furadonin and furazolidone. In concentrations of 50 to 500 gamma-ml oleadomycin, chlortetracycline, oxytetracycline, kanamycin and ristomycin inhibited synthesis of the Cheres yeast biomass. Benzylpenicillin, polymyxin, neomycin and ampicillin in concentrations of 50 to 100 gamma/ml had a stimulating effect on the yeast biomass synthesis.     

Sensitivity of pathogenic clostridia to antibiotics]

By the sensitivity levels of the gas infection causative agents, i. e. pathogenic Clostridia to antibiotics, the latter were conditionally divided into 4 groups. The 1st group included the most active antibiotics, such as tetracyclines,, penicillins, cephalosporins, rifampicin, 7-chlor-7-desoxylincomycin. Their minimum inhibitory and bactericidal concentrations did not usually exceed 2 gamma/ml. For most of the strains the inhibitory and bactericidal concentrations amounted to the tenth and hundredth fractions of gamma/ml. The antibiotics of the 2nd group, i. e. erythromycin, lincomycin,ristomycin and levomycetin inhibited multiplication and viability of pathogenic Clostridia in concentrations of 20 gamma/ml. Erythromycin was most active among them The 3rd group consisted of oleandomycin, novobiocin, geliomycin and azalomycin, the minimum inhibitory concentrations of them being 20 to 50 gamma/ml. The antibiotics of the 4th group, i. e. neomycin, monomycin, kanamycin, streptomycin, polymyxin and others affected pathogenic Clostridia at very high concentrations, amounting to the hundrenth and thousandth of gamma/ml.     

Dynamics of drug resistance of Vibrio cholerae isolated from surface water reservoirs in Siberia and the Soviet Far East in 1976-1990]

In the study on antibiotic resistance 1383 strains of El Tor Vibrio cholerae isolated from surface water reservoirs in 12 administrative territories of the Siberia and Far East within a period of 15 years were tested. The following antibiotics were used: ampicillin, streptomycin, monomycin, polymyxin, tetracycline, chloramphenicol, rifampicin and nalidixic acid. The resistance was unstable and its pattern was wave-like according to annual changes in the biological cycle. It was especially evident in regard to ampicillin, streptomycin, monomycin and polymyxin. The highest numbers of the strains were resistant to polymyxin, ampicillin and streptomycin (up to 100 per cent in some years). The lowest numbers of the strains were resistant to chloramphenicol (0.4 per cent) and tetracycline (1.9 per cent). No strains resistant to rifampicin and nalidixic acid were isolated. In some cases the antibiotic resistance level depended on the geographical zone where the strain was isolated. A direct quantitative dependence of the resistance level on the MIC was observed: the lower the MIC of the drug was, the lower the number of the strains resistant to it was. Within the 15-year period there was no general tendency to increase the resistance in V. cholerae to the antibiotics used.     

Susceptibility of sixty-five non-oral clinical isolates of the Streptococcus milleri group to seven antimicrobial agents.

Antimicrobial susceptibilities of sixty-five non-oral Streptococcus milleri group clinical isolates to penicillin, gentamicin, lincomycin, ampicillin, chloramphenicol, tetracycline and erythromycin were determined by an agar dilution method. All strains were penicillin-sensitive (MIC < or = 0.031 microgram/ml) and the majority (64/65) were susceptible to erythromycin (MIC < or = 0.125 microgram/ml). Low-level resistance to gentamicin was observed, and the majority of strains possessed an MIC of 8 micrograms/ml. Lincomycin and ampicillin at 0.5 microgram/ml inhibited 52/65 and 61/65 strains, respectively. Of the isolates 92% were inhibited by chloramphenicol at < or = 2 micrograms/ml. Twenty-two S. milleri group strains (of which thirteen were vaginal isolates) were resistant to tetracycline (MIC > or = 8 micrograms/ml).     

Rapid evaluation of the effectiveness of antibacterial drugs in experimental tularemia

Rapid estimation of the protective effect of antibacterial drugs on Fransiella tularensis for not more than 2 days was shown possible in experiments on albino mice infected with tularemia. High efficacy of aminoglycosides (kanamycin, gentamicin, streptomycin, amikacin, netilmicin, tobramycin, sagamycin, ribostamycin and sisomicin), tetracyclines (tetracycline, doxycycline, minocycline and methacycline), rifampicin, phosphomycin and oxolinic acid was determined with the recommended rapid method. Amoxycillin, ampicillin, piperacillin, carbenicillin, erythromycin, levomycetin, cefradine, cefmetazole, cefatrizine, cefoxitin, cefsulodin and bactrim (biseptol) proved to be inefficient against the tularemia causative agent.     

Antibiotic sensitivity of plague microbe strains from foreign countries]

The method of serial dilutions on the Hottinger agar was applied to comparative assay of antibiotic sensitivity in 50 strains of the plague microbe isolated abroad and in 5 strains isolated in the plague focus in the Central Caucasus. The antibiotics used in the assay were the following: streptomycin, gentamicin, doxycycline, monomycin, kanamycin, tetracycline, erythromycin, ristomycin, lincomycin and polymyxin M. Irrespective of the origin, all the isolates were resistant to erythromycin, lincomycin and polymyxin M. The levels of the sensitivity to the other antibiotics were different. The data serve as a ground for the statement that there is no tendency to development of antibiotic resistance in the plague microbe in patients treated with high doses of the antibiotics and mainly streptomycin. Along with streptomycin, such antibiotics as gentamicin, tetracycline, doxycycline and kanamycin are useful in the therapy of plague and require further investigation.     

Geographical race typing of the causative agent of tularemia using antibiotics]

Reaction of the strains of the tularemia causative agent to erythromycin (100 gamma/ml) or oleandomycin (400 gamma/ml) is one of the taxonomic tests. The study of 82 strains of the holarctic race and 63 strains of the Central Asiatic race according to this test showed that the strains of the holarctic race were divided with respect to these macrolides into sensitive (biotype I) and resistant (biotype II). The strains of the both races were isolated at the territory of the Kazakh SSR. Such a reaction of the strains of the holarctic race is a stable feature and is not connected with virulence, the isolation source and the biochemical properties of the strains. Division of the holarctic race into the biotypes (I and II) with respect to erythromycin and oleandomycin may be of definite significance in epidemiological and epizootological examination for tularemia with a purpose of determining the source of the infection, as well as in defining the borders of the infection focus area with circulation of this or that biotype of the holarctic race of the tularemia causative agent.     

Antibiotic resistance of Pseudomonas aeruginosa strains isolated from patients with infected burns

Sensitivity to 15 drugs of 248 P. aeruginosa strains isolated from patients with infected burns was studied by the method of agar dilution. All of the strains were resistant to polymyxin M, ceporin, erythromycin and oleandomycin. Most of the strains were resistant to streptomycin, monomycin, ampicillin and rifadin. Moderate resistance of the strains to carbenicillin, morphocycline, vibramycin, kanamycin, tetraolean and tetracycline was observed: the maximum concentrations of these antibiotics (128 microgram/ml) inhibited the growth of 85, 69, 63, 51.8, 43.6 and 41.2 per cent of the strains respectively. Gentamicin proved to be most active against the strains of P. aeruginosa and inhibited 87 per cent of the strains when used in the therapeutic doses. The study provided recomendation of the drugs for parenteral and local use in treatment of burns infected with P. aeruginosa.     

Comparative analysis of antibiotic sensitivity of Streptococcus pneumoniae strains isolated from patients and carriers

The data on antibiotic sensitivity of 38 strains of S. pneumoniae isolated from children and 46 strains isolated from carriers are presented. The isolates from the carriers had significantly higher sensitivity to benzylpenicillin, ampicillin, methicillin, oxacillin, cefazolin, erythromycin, oleandomycin and lincomycin. Resistance to gentamicin was more frequent in the strains isolated from the carriers. Among the strains of S. pneumoniae isolated from the patients and carriers representatives of serovar K19 were more frequent. There were no statistically reliable difference in them by sensitivity to benzylpenicillin, ampicillin, cefazolin, lincomycin and rifampicin. Still, the isolates from the carriers were much more sensitive to methicillin, oxacillin, oleandomycin and erythromycin.     

Antibiotic sensitivity of the causative agents of suppurative surgical infection]

Sensitivity of 1492 strains of the causative agents of the surgical purulent infections, i. e. pathogenic Staphylococcus, Proteus, Ps. aeruginosa and E. coli to benzylpenicillin, streptomycin, levomycetin, tetracycline, erythromycin, oleandomycin, monomycin, kanamycin, novobiocin, ampicillin, oxacillin, ceporin, gentamicin and rifampicin was studied. Gentamicin was most active against all the bacterial species tested. The staphylococci were in addition sensitive in a high percentage of the cases to rifampicin, novobiocin, ceporin, monomycin and kanamycin. The isolates of E. coli were in addition sensitive to ceporin, monomycin and kanamycin. Sensitivity of the strains of Ps. aeruginosa and Proteus was low to all of the antibiotics except gentamycin. Most of the strains of the causative agents of the surgical purulent infections were multiresistant to 4 antibiotics. The number of the staphylococcal strains sensitive to benzylpenicillin, streptomycin and levomycetin increased in 1976 as compared to 1975 on the background of a limited use of these antibiotics in clinics.     

Sensitivity of various races of the tularemia microbe to erythromycin, oleandomycin and polymyxin]

Sensitivity of 66 strains of the tularemia microbe to erythromycin, oleandomycin and polymyxin was studied. It was shown that all the strains were resistant to polymyxin. The strains of the non-artic and Central Asiatic races and 64 per cent of the strains of the holarctic race were resistant to erythromycin and oleandomycin.     

Sensitivity to antibacterial preparations of the pseudotuberculosis bacteria isolated on the territory of the Ukraine]

Sensitivity of 92 strains of the causative agent of pseudotuberculosis isolated in the Ukraine was studied with respect to 26 antibacterial drugs. It was found that the strains of the pseudotuberculous bacteria were sensitive to 17 drugs, i.e. benzylpenicillin, ampicillin, carbenicillin, cephaloridin, chloramphenicol, tetracycline, streptomycin, neomycin, monomycin, kanamycin, gentamicin, polymyxin, colistin, furadontin, nalidixic acid, sulfisoxazol and septrin. No differences in the sensitivity of the strains isolated in various districts of the Ukraine and from various sources were found. By their antibiotic sensitivity the strains isolated in the Ukraine did not differ from the cultures isolated in other districts of the USSR and abroad.     

Action of Lincomycin on Staphylococci

On a solid medium, 0.1 to 1 μg/ml of lincomycin hydrochloride had a bacteriostatic effect upon 95 of 100 strains of staphylococci. Using cellophane transfers, we observed a bactericidal effect upon 54 of these strains after 3 to 14 hr of contact with 1 μg/ml. Five staphylococcal strains resistant to 100 μg/ml of lincomycin were also resistant to penicillin G, streptomycin, erythromycin, tetracycline, chloramphenicol (three strains), and rovamycin (three strains). Other staphylococcal strains resistant to methicillin, ampicillin, tetracycline, streptomycin, chloramphenicol, and erythromycin were sensitive to lincomycin.     

Antibiotic resistance of Shigella in different regions of the USSR]

Shigella were most sensitive to polymyxin ceporin, ampicillin, neomycin and furazolidone and resistant to chloramphenicol, tetracycline and streptomycin. Shigella resistant simultaneously to two or three drugs mainly to tetracycline + chloramphenicol, tetracycline + streptomycin and tetracycline + chloramphenicol + streptomycin were most frequent. The frequency of the Shigella strains carrying R-plasmids increased from 28 per cent in 1969--1970 to 72.6 per cent in 1977. The Shigella strains isolated during the dysentery outbreak in 1973--1977 carried the R-factor controlling resistance to tetracycline + chloramphenicol, tetracycline + chloramphenicol + streptomycin, tetracycline + chloramphenicol + streptomycin + neomycin. Interaction between separate biochemical types, colicinogenicity and drug resistance classes was found in the Shigella isolates. The data on the effect of antibiotic (tetracyclines) intensive use in stock-raising defining wide spread of the R-plasmids controlling resistance to these drugs were obtained.     

The sensitivity to 12 antibiotics of 125 strains of Streptococcus group B isolated in a maternity home

Sensitivity of 125 strains of group B streptococci isolated from newborns, their mothers and personnel in a maternity home was studied with respect to 12 antibiotics: benzylpenicillin, ampicillin, methicillin, cephalotin, erythromycin, lincomycin, levomycetin (chloramphenicol), oxacillin, tetracycline, streptomycin, gentamicin and ristomycin. The method of serial dilutions in a solid medium was applied. All the strains were sensitive to ristomycin and erythromycin. The predominating number of the strains were sensitive to lincomycin, levomycetin and the beta-lactam antibiotics. Strains resistant or moderately resistant to benzylpenicillin, ampicillin, oxacillin, methicillin and cephalotin were detected. The majority of the strains were resistant to streptomycin, tetracycline and gentamicin. Multiple antibiotic resistance with 2-7 determinants was revealed in 11.2 per cent of the strains. The antibiotic sensitivity of the strains isolated from the newborns, their mothers and the personnel in the maternity home was on the whole similar or insignificantly differed.     

Sensitivity of Mycoplasma hominis cultures isolated from clinical material to certain antibiotics]

Sensitivity to II antibiotics of 80 strains of M. hominis isolated from patients with various inflammatory processes of the urogenital tract was studied by the method of suppressing the metabolic activity. Inhibition of the arginine metabolism of mycoplasma was used as a test for determination of the growth suppression. All the strains tested were highly sensitive to tetracycline and lincomycin. Kanamycin and neomycin were less active against M. hominis. All the strains tested were resistant to erythromycin, oleandomycin, ristomycin, novobiocin and streptomycin. The inhibitory effect of tetracycline and lincomycin on M. hominis decreased by the 5th day.     

Susceptibility of Salmonellae to Cephalosporins and to Nine Other Antimicrobial Agents

Three cephalosporin-related antibiotics and nine other antimicrobial agents were studied for in vitro effectiveness against 54 recently isolated strains of Salmonella. Minimal inhibitory concentrations determined by the plate dilution method demonstrated the following percentages of resistance: ampicillin, 6%; tetracycline, 13%; streptomycin, 52%; sulfadiazine, 94%; cephaloglycin, 96%; and lincomycin, 100%. No strains were resistant to cephalothin, cephaloridine, chloramphenicol, colistimethate, kanamycin, and polymyxin B. The commonest serotype studied, S. typhimurium, showed the greatest antibiotic resistance, with 21% resistant to ampicillin, 36% resistant to tetracycline, and 71% resistant to streptomycin. Cephalothin and cephaloridine were highly effective in vitro but inhibitory concentrations of 20 to 40 mug of cephaloglycin per ml were required for the majority of Salmonella strains.     

Effect of lytic enzymes on Staphylococcus and the possibilities of their combined use with antibiotics

Dependence of lytic enzyme preparation activity on temperature and time of Staphylococcus incubation with the preparation was shown. A decrease in the activity with an increase in the ionic strength of the incubation solutions and protective effect of salts on the staphylococcal cells were observed. Possible combined use of the preparation with antibiotics was studied. The enzymatic preparation inactivated penicillins and cephalosporins at the account of the ability of lytic endopeptidases to hydrolyze the peptide bond of the beta-lactam ring. However, its combined use with many other antibiotics such as novobiocin, lincomycin, rifampicin, gramicidin, polymyxin, oleandomycin, streptomycin, kanamycin, tetracycline and levomycetin is quite possible.     

Study of the sensitivity of the L-forms of group A Streptococcus to antibiotics in artificial nutrient media and in human cell cultures

Sensitivity of L-forms of group A streptococci to 5 antibiotics such as erythromycin, lincomycin, tetracycline, gentamicin and chloramphenicol was studied in an artificial nutrient medium and cell cultures i.e. human fibroblast diploid cells and transplantable human heart cells (Girardi). In vitro investigation of the antibiotic effect on the streptococcal L-forms revealed their sensitivity to erythromycin (MIC, 0.4 micrograms/ml), lincomycin (MIC, 0.08 microgram/ml) and tetracycline (MIC, 2 micrograms/ml). The streptococcal L-forms were slightly sensitive to gentamicin (MIC, 6 micrograms/ml) and chloramphenicol (MIC, 30 micrograms/ml). Complete inhibition of the growth of the L-forms in the Girardi cells on the 1st day of the experiment after the antibiotics administration in single doses was induced by lincomycin, 5 micrograms/ml, erythromycin, 10 micrograms/ml, and tetracycline, 100 micrograms/ml. In the diploid cells, the respective figures were 50, 100 and 200 micrograms/ml. Chloramphenicol and gentamicin had an inhibitory effect on the growth of the L-forms but produced no sanative effect.     

Production of toxic shock exotoxin by Staphylococcus aureus strains resistant and sensitive to antibiotics

Three hundred and ninety two strains of S. aureus isolated from bacteria carriers and patients with staphylococcal infections in different regions of the Soviet Union were investigated. 55.9 per cent of the isolates were able to produce exotoxin of toxic shock. No regular relation between resistance to definite antibiotics (tetracycline, chloramphenicol, benzylpenicillin, streptomycin, lincomycin, erythromycin, oleandomycin, gentamicin and methicillin) and the polyresistance range on the one hand and the ability to produce toxic shock exotoxin on the other hand was revealed.