Structure of the antibiotic resistance of the salmonellae found in Transcarpathia]

Resistance of 1280 strains of Salmonella of various serological types isolated in the Zakarpatskaya region within 1967-1976 was studied with respect to benzylpenicillin, streptomycin tetracycline, levomycetin, monomycin, neomycin, erythromycin and oleandomycin. An Increase in the resistance of Salmonella to streptomycin, tetracycline, levomycetin, monomycin and neomycin was shown. During the last years Salmonellae carrying 4-8 resistance determinants were spreading in the region. Among S. typhimurium strains with 7-8 resistance determinants predominated (58.8 per cent). The cases of salmonollosis were mainly due to these strains.     

Action of antibiotic combinations with furacilin on the synthesis of proteins and nucleic acids in intact NAG-vibrio cells]

Furacillin in combination with such antibiotics as tetracycline, levomycetin or neomycin inhibited the synthesis of proteins in the cells of NAG-vibrios. Combination of 8 gamma/ml of furacillin and 0.125 gamma/ml of tetracycline inhibited the protein synthesis by 58.8 per cent, 8 gamma/ml of furacillin and 0.5 gamma/ml of levomycetin inhibited the synthesis by 61 per cent, 8 gamma/ml of furacillin and 4 gamma/ml of neomycin inhibited it by 59.5 per cent. At the same time furacillin alone in concentrations of 16 and 8 gamma/ml inhibited the protein synthesis by 69.1 and 37 per cent respectively, tetracycline alone in doses of 0.25 and 0.125 gamma/ml inhibited it by 51.3 and 34.7 per cent respectively, levomycetin alone in doses of 1 and 0.5 gamma/ml inhibited it by 54.4 and 33.2 per cent, enomycin in doses of 8 and 4 gamma/ml inhibited it by 54.4 and 22.6 per cent respectively. Therefore, when the above antibiotics were used in combination with furacillin the inhibitory effect of the drugs on the protein synthesis was summarized. When furacillin was combined with tetracycline or levomycetin in the above concentrations, the inhibitory effect on RNA synthesis (42 or 32 per cent respectively) was lower than that of furacillin alone (50.5 per cent). When furacillin was used in combination with neomycin, the inhibition of RNA synthesis increased up to 69 per cent. The increase in the inhibitory effect was also noted with respect to the synthesis of DNA. Combination of furacillin with tetracycline, levomycetin or neomhcin decreased the synthesis of DNA by 79.7, 85 or 85.8 per cent respectively as compared to the inhibitory effect of 8 gamma/ml of furacillin equal to 61 per cent.     

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 Shigella to antibiotics]

Three hundred and twenty two Shigella cultures isolated from dysentery patients within 1986-1989 were tested with the use of standard paper disks for their sensitivity to levomycetin, streptomycin, tetracycline, monomycin, neomycin, kanamycin, erythromycin, gentamicin, carbenicillin, ampicillin, oxacillin, methicillin and doxycycline. The number of the cultures belonging to Shigella sonnei amounted to 85.1 per cent of the total number of the strains studied. 91.9, 89.5, 87.3, 87.3, 80.1 and 80.1 per cent of the cultures were sensitive to gentamicin, kanamycin, carbenicillin, neomycin, levomycetin and ampicillin, respectively. 99.4 per cent of the isolates were resistant to streptomycin and 97.2 per cent were resistant to tetracycline. The sensitivity to erythromycin remained rather high (70.2 per cent). The overwhelming majority of the Shigella sonnei isolates had multiple resistance.     

Antibiotic resistance dynamics of plasma-coagulating staphylococci isolated from patients in 1970-1975]

Resistance of 2345 strains of plasmocoagulating staphylococci isolated from purulent inflammatory foci of surgical patients was studied with respect to the widely used antibiotics by the method of standard paper discs in 1970--1975. It was noted that the cultures resistant to erythromycin and monomycin were more frequent, i.e. from 24.2 +/- 2.5 to 51.4 +/- 3.4 per cent and from 1.0 +/- 0.6 to 28.0 +/- 2.1 per cent respectively, p less than 0.001 in both cases, while the percentage of the strains resistant to benzylpenicillin and tetracycline steadily increased, i.e. from 69.9 +/- 2.4 to 47.0 +/- 2.3 per cent and from 72.8 +/- 2.4 to 28.4 +/- 2.1 per cent respectively, p less than 0.001 in both cases. The number of the resistant cultures to streptomycin and levomycetin slightly changed and was relatively high (about 50 per cent and more). Direct correlation (mean and pronounced) between the amount of levomycetin, tetracycline, erythromycin or monomycin used per citizen of Minsk and the frequency of the strains isolated from the patients to these drugs was noted.     

Effect of thiamine, riboflavin and ascorbic acid on tetracycline, erythromycin and levomycetin activity]

The effect of antibiotics was estimated by inhibition of the protein increase in the broth culture of Staph, aureus during incubation at a temperature of 37 degrees for 18 hours. In some experiments preincubation of the antibiotic solutions with the vitamins for 2 hours at light and in dark was used. The antibiotic concentrations in gamma per 1 ml were equal to those of the vitamins. In the experiments with tetracycline and 2-hour preincubation at light the antibiotic in a concentration of 0.1gamma ml inhibited for certain the protein increase by 58.9%, in combination with thiamin it inhibited the protein by 60 per cent and in combination with ascorbic acid by 59%. Riboflavin lowered the activity of tetracycline to a value not differing for certain from the control one. In the experiments with preincubation in dark tetracycline inhibited the protein increase by 55.2%, in combination with thiamin it inhibited the protein increase by 50.5%, in combination with riboflavin by 53% and in combination with ascorbic acid by 57.2%. Erythromycin in a concentration of 0.03gamma/ml when preincubated at light inhibited the protein increase by 48.8% and in combinations with thiamin, riboflavin or ascorbic acid by 23, 27, 47.2% respectively. When preincubated in the darkness erythromycin alone inhibited the protein increase by 47.8% and in combinations with thiamin, riboflavin or ascorbic acid by 32.5, 51.1 or 49.8% respectively. The above vitamins has no effect on levomycetin activity.     

Comparison of the sensitivity of Pseudomonas aeruginosa cultures that synthesize melanin and other pigments to 12 antibiotics and 5-nitro-8-quinolinol]

Sensitivity of 80 Pseudomonas aeruginosa cultures forming melanin and 80 cultures synthesizing other pigments to amikacin, gentamicin, kanamycin, carbenicillin, levomycetin, monomycin, 5-NOK, polymyxin M, rifampicin, streptomycin, tetracycline, tobramycin and erythromycin was determined. It was found that the cultures of Ps. aeruginosa synthesizing melanin were less resistant to most of the antibiotics that the other representatives of this species.     

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.     

Ultrastructural changes in populations of the pertussis microbe exposed to antibiotics

The ultrastructural changes in the populations of the pertussis causative agent maintained for a prolonged period of time on nutrient media containing antibiotics were studied with the method of electron microscopy. Significant changes in the ultrastructure of the cells and the population composition due to the effect of tetracycline, levomycetin or erythromycin were observed. The ultrastructure of the populations affected by penicillin or streptomycin and their biological properties were most similar to those of the initial strains. The electronogrammes revealed morphological heterogeneity of the initial and experimental cultures and changes in the subpopulation composition induced by the antibiotics.     

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.     

Antibiotic sensitivity of the erythromycin-resistant strain E of Rickettsia prowazekii cultured in the vector's body

Experiments on the laboratory cultures of lice infected by Weigl's method revealed that the spontaneous, erythromycin-resistant mutant of R. prowazekii strain E, adapted to the vector's organism, retained its resistance to erythromycin during 50 successive passages without the maintenance concentrations of this antibiotic. The above strain remained sensitive to tetracycline and levomycetin. Its level of sensitivity to the latter antibiotics was similar to that of R. prowazekii strains cultivated in the vector's organism for a long time.     

E. coli resistance to antibiotics on the material studied and the structure of the antibiotic resistance of the strains]

Standard filter paper discs were used to determine the sensitivity of 943 strains of E. coli isolated in 1970-1974 from patients' purulent-inflammatory foci with respect to benzylpenicillin, streptomycin, levomycetin, tetracycline, erythromycin and monomycin. An increase in the specific weight of the cultures resistant to the 6 drugs from 4.7 +/- 1.7 per cent in 1970 to 16.0 +/- 2.6 per cent in 1974 was observed. Strains resistant to 5--6 antibiotis were more often isolated from the urine (64.6 per cent) and the wound content (48.9 per cent) and rarer from the abdominal cavity exudate (23.1 per cent), bile (28.0 per cent) and sputum (30.1 per cent). Most often certain combinations of resistance to benzylpenicillin, streptomycin, tetracycline and erythromycin were found in the E. coli strains tested.     

Sensitivity to antibacterial preparations of the pathogenic staphylococci isolated from carriers]

After discontinuation of the use of antibiotics for sanation of the carriers of pathogenic staphylococci among the staff of a maternity unit, the number of the strains resistant to penicillin, streptomycin, chlortetracycline, tetracycline, levomycetin, erythromycin, monomycin and neomycin decreased 1.3, 2.9, 10,4.3,5.5,1.5,3.9 and 2.4 times respectively. The differences were statistically reliable. The causes of the antibiotic resistance decrease require further investigation.     

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.     

Antibiotic sensitivity of beta-hemolytic Streptococcus group A on a new nutrient medium for the cultivation of streptococci

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.     

Coamide stimulation of immunogenesis during experimental levomycetin therapy]

The effect of various doses of levomycetin on immunogenesis and capacity of coamide for stimulation of immunogenesis in levomycetin therapy was studied. It was found that massive five-fold doses of levomycetin sodium succinate (I and 0.5 g/kg) administered parenterally or orally inhibited immunogenesis, the inhibition being more pronounced on administration of the antibiotic per os. When levomycetin sodium succinate was used in massive doses (1 g/kg) in combination with coamide (0.5 mg/kg) the inhibition of the immune response to the antigenic stimulation was less pronounced.     

Administration of antibiotics in combination. Determination of antibacterial effectivity of blood serum and urine after simultaneous administration of macrolides and tetracyclines.

The authors deal with antibacterial effectivity of blood serum and urine in simultaneous administration of macrolids and tetracyclines under in vivo conditions, using Staphylococcus aureus strains. The obtained results suggest that pharmacodynamic effect, i.e., higher effective concentration, is induced in some combinations of these preparations. It was found mainly after the administration of the combinations of erythromycin 250 mg + doxycycline 200 mg in all the chosen reference strains S. a. The results have also shown that the combination of erythromycin with tetracycline has a higher effect when an erythromycin-resistant strain is used than when using a strain resistant to tetracycline.     

Antibiotic sensitivity of S. typhi cultures that have reverted from L forms isolated from the blood of patients]

L-forms of bacteria were isolated in 18 out of 300 fever patients with diagnoses of typhoid-paratyphoid fever, grippe, virus respiration disease and others in the Diagnostic Department of an Infection Hospital during bacteriological tests of the blood. Among the cultures tested 13 were instable and reversed to the bacterial form. The type identification showed that only 9 revertants possessed properties characteristic of the typhoid fever microbes and belonged to S. typhi. Sensitivity of the typhoid fever revertants to levomycetin, sintomycin, streptomycin, pencillin and tetracycline was studied. The studies showed that the typhoid fever revertants from the L-forms isolated from the patients were sufficiently sensitive to levomycetin, sintomycin, penicillin and tetracycline. The minimum bactericidal concentrations of the above antibiotics ranged within 12.5--100 gamma/ml.     

Factors of multiple resistance to antibiotics in nodule bacteria]

Multiple resistance to antibiotics (penicillin, levomycetin, neomycin, tetracycline) was found in 15% of collection strains of nodule bacteria and in strains isolated from natural environment.     

Study of the antibiotic sensitivity of the Shigellae, pathogenic Escherichia, Proteus and Staphylococcus isolated from young children in Tbilisi with acute intestinal diseases]

Sensitivity of Shigella, pathogenic Escherichia, Proteus and Staphylococcus isolated from children with acute intestinal diseases was studied with respect to antibiotics widely used in medical practice: streptomycin, levomycetin, tetracycline, chlortetracycline, oxytetracycline and neomycin. The antibiotic sensitivity was determined with the method of indicator discs. It was found that sensitivity of shigella was: 44 percent to streptomycin, 69.5 per cent to levomycetin, 18.5 per cent to tetracycline, 18.5 per cent to chlortetracycline, 23 per cent to oxytetracycline and 94 per cent to neomycin. Sensitivity of pathogenic Eschericia was 28, 33, 14, 14, 25 and 74 per cent, sensitivity of staphylococci was 46, 56.5, 21, 21, 31.5 and 89.5 per cent, sensitivity of Proteus was 15, 31.5, 3.5, 3.5, 7.5 and 52.5 per cent respectively. Cross resistance with respect to tetracyclines was found in all the microbes studie. Intragenera differences in the antibiotic sensitivity were observed among Shigella and pathogenic Escherichia.