Effect of proteolytic enzymes on antibiotic distribution when the preparations are administered by different routes]

The effect of proteolytic enzymes, such as terrilitine and chymotripsin on pharmacokinetics of morphocycline and streptomycin in rats after their administration by various routes was studied comparatively. The oral use of the enzymes or their introduction directly into the duodenum simultaneously or 30 minutes before the antibiotic administration did not increase the morphocycline and streptomycin levels in the biosubstrates tested. A tendency to a decrease in the serum and organ levels of the antibiotics in animals when used orally in combination with the enzymes was noted. When the drugs were administered intramuscularly, the morphocycline serum and organ levels in the rats increased insignificantly, while the streptomycin levels increased significantly. Administration of formalin as a stressor had an analogous effect which provided a supposition of a possibility of non-specific effect of the enzymes of distribution of the antibiotics on intramuscular injection of the enzymes in large doses having a local irritating effect.     

Comparative study of the relationship between the blood concentration of gentamicin and streptomycin and their muscle-relaxing activity]

A mathematical model of relation between the miorelaxant effect value of aminocyclitol antibiotics and their blood levels is proposed. The kinetics of the reduction of the neuromuscle transmission damaged under the action of the drugs was studied in detail in acute experiments with cats treated with gentamycin or streptomycin administered intravenously. The changes in the effect value in time were satisfactorily described by the logistic function. Parallel determination of the blood levels of the antibiotics in the animals provided construction of an adequate model of their pharmacokinetics. Tabulation of the corresponding biexponential equations and logistic functions for the same time intervals during reduction of the neuromuscle transmission provided necessary information for plotting the "effect: concentration" curves. Comparison of the drug levels at which the effect of inhibition of the neuromuscle transmission was equal to 50% of the maximum one, revealed a statistically reliable difference in the miorelaxant activity of gentamycin and streptomycin. A high miorelaxant activity of gentamycin in comparison to streptomycin was also shown on comparison of the average "effect: concentration" curves plotted on the basis of tabulation of the general equations presenting a combination of the logistic and biexponential equations.     

Sensitivity to Rifampicin: Incidence,Mechanism, and Prevention

Five out of 200 patients taking rifampicin 900 mg twice weekly and three out of 91 patients taking rifampicin who attended an immunology clinic developed intolerance to the drug. Antibodies to rifampicin, which were found in most cases, decreased steadily after the end of treatment but were detectable for up to 16 months. The dose of rifampicin and the blood levels are predominating factors in the occurrence of reactions. Thus the dose should be reduced in patients in whom rifampicin blood levels rise abnormally. When it is important to continue rifampicin treatment despite intolerance antibody titres within 24 hours after administration of the drug must be measured to find when they are lowest, which determines the “unreactive period,” and when a further dose may be safely given.     

Efficacy of plague prophylaxis with streptomycin, tetracycline, and rifampicin in simultaneous immunization of white mice by resistant EV NRIEG strain]

Tetracycline, doxycycline, streptomycin and rifampicin were used for prophylaxis of experimental plague in albino mice (Yersinia pestis 231, approximately 1000 LD50). The antibiotics were administered 5 hours after the infection for 5 days. Tetracycline and doxycycline provided survival of 60 to 75% of the animals, while the respective figure for streptomycin and rifampicin was 100%, but streptomycin and rifampicin inhibited development of plague immunity evident from a lower protection index (PI) by 3-4 orders. The PI for the tetracyclines lowered by 2 orders. Simultaneous prophylaxis with the tetracyclines and immunization by Y. pestis EV Rifr R(SmTc) (10(6) microbial cells) provided not only higher percentage of the animal survival (80-90%) but also development of sufficient plague immunity: PI of 1.0 x 10(5)--5.0 x 10(5). When the animals were infected with Y. pestis 231 R(SmTc) the use of the tetracyclines failed, whereas the use of doxycycline and simultaneous vaccination by EV Rifr R(SmTc) provided survival of 70-85% of the animals. Successive use of inefficient streptomycin (for 2 days) and efficient rifampicin (for 3 days) provided survival only of 30% of the mice. A similar regimen of the successive use of the inefficient and efficient antibiotics (the total term of 5 days) started simultaneously with immunization by EV Rifr R(SmTc) provided survival of 80% of the animals. The use of combined specific and urgent prophylaxis of plague infection due not only to antibiotic susceptible but also to antibiotic resistant strains of the plague pathogen was shown promising.     

Determination of plasmid transfer frequency in soil: Consequences of bacterial mating on selective agar media

The possible occurrence of bacterial matings on transconjugant-selective plates used in experiments aimed at assessing conjugal transfer in soil was investigated. Matings on transconjugant-selective plates (with rifampicin, streptomycin, tetracycline, and kanamycin) between donor and recipient cells were shown to occur depending on the number of parent cells. Temperature also influenced conjugation frequencies on agar plates, since a lower temperature resulted in a decreased number of transconjugants. The use of nalidixic acid instead of streptomycin in conjunction with rifampicin for donor counter selection inhibited conjugation on selective plates. Conjugation in soil was analyzed by plating on selective media with nalidixic acid or streptomycin. The results indicated that conjugation in bentonite- or nutrient-amended soil was readily detected; however, part of the transconjugants could be assigned to be the result of matings on the selective plates. Conjugation was also stimulated in the presence of plant roots. Colony hybridization experiments confirmed the presence of plasmid RP4 in the transconjugants.     

Dependence of the nephrotoxic effect of kanamycin on its concentration in the blood (an experimental study)]

The kinetics of changes in the urea nitrogen level of the serum was studied experimentally on narcotized cats with constant blood levels of kanamycin. A relationship between the intensity of the nephrotoxic effect of kanamycin and its blood level was found. On the basis of this relationship lower nephrotoxicity of kanamycin as compared to that of gentamicin and streptomycin under conditions of their constant blood levels was shown. However, the concentrations of gentamicin and kanamycin provided in the blood by their use in therapeutic doses differeing 3--4 times allow a conclusion that the nephrotoxic effect of kanamycin and gentamicin to be practically the same.     

Bioluminescent Mycobacterium aurum expressing firefly luciferase for rapid and high throughput screening of antimycobacterial drugs in vitro and in infected macrophages

The slow growth and highly infectious nature of Mycobacterium tuberculosis is a limiting factor in its use as test organism in high throughput screening for inhibitory compounds. To overcome these problems, use of surrogate strains and reporter genes have been considered. In this study, we have investigated the application of a fast growing nonpathogenic M. aurum expressing firefly luciferase in rapid screening of antituberculosis compounds in vitro and in infected macrophages using bioluminescence assay. The assay is based on luminescence determination using luciferin as substrate. Inhibition of bioluminescence was obtained with frontline antimycobacterial drugs like streptomycin, rifampicin, isoniazid, ethambutol, ofloxacin, and sparfloxacin at their reported MICs. Inhibition could be observed as early as 2 h in vitro and within 24 h in infected macrophages. The system can reliably be used in high throughput screening.     

Hypotension caused by intravenous infusion of rifampicin and its relation to the administration schedule

It was shown in studies on animals that bolus administration of rifampicin induced hypotension whose severity depended on the rate of the antibiotic administration. When the antibiotic was administered in the 5-, 10- or 15-minute regimen in a dose of 10 mg/kg the maximum decrease in blood pressure was 44, 34 or 21% of the initial level and the maximum antibiotic concentration attained in the blood was 34.4, 27.2 or 22.6 micrograms/ml, respectively. With the infusion for 30 minutes, the maximum antibiotic concentration in the blood was 17.6 micrograms/ml and the blood pressure did not undergo any significant changes. When the rate of the antibiotic infusion was high there was pharmacokinetic heterogeneity of the blood serum and biophase which could lead to unpredictable results. After repeated administrations of rifampicin to the same animals pronounced tachyphylaxis to the antibiotic was noted, which manifested itself in decreasing of hypotension, though the serum antibiotic level was 1.5 to 2 times higher that the initial one. It was concluded that administration of rifampicin in the therapeutic dose equal to 10 mg/kg for 30 minutes was the most sparing regimen for the antibiotic bolus intravenous infusion. Gradual increase in the antibiotic dose and administration rate in patients is possible under careful control of blood pressure and pharmacokinetic studies.     

Autoradiographic Evidence for the Impermeability of Mouse Peritoneal Macrophages to Tritiated Streptomycin

Cultured mouse peritoneal macrophages were found to be relatively impermeable to streptomycin. Based on radioactivity measurements and radioautographic evidence, macrophages were impermeable to tritiated dihydrostreptomycin for periods up to 20 hr of incubation. Little or no intracellular streptomycin could be detected even when incubation was carried out in the presence of therapeutic blood levels of carrier dihydrostreptomycin. When the cultured mouse macrophages were allowed to phagocytize staphylococci, yeast cells, or polystyrene latex particles in the presence of tritiated streptomycin, the impermeability of the cells to the antibiotic was not affected. These observations suggested that the process of phagocytosis does not facilitate the intracellular accumulation of streptomycin, as seems to be the case for the fixed phagocytic cells of the liver.     

Long Term Streptomycin Toxicity in the Treatment of Buruli Ulcer: Follow-up of Participants in the BURULICO Drug Trial

Background

Buruli Ulcer (BU) is a tropical infectious skin disease that is currently treated with 8 weeks of intramuscular streptomycin and oral rifampicin. As prolonged streptomycin administration can cause both oto- and nephrotoxicity, we evaluated its long term toxicity by following-up former BU patients that had received either 4 or 8 weeks of streptomycin in addition to other drugs between 2006 and 2008, in the context of a randomized controlled trial.

Methods

Former patients were retrieved in 2012, and oto- and nephrotoxicity were determined by audiometry and serum creatinine levels. Data were compared with baseline and week 8 measurements during the drug trial.

Results

Of the total of 151 former patients, 127 (84%) were retrieved. Ototoxicity was present in 29% of adults and 25% of children. Adults in the 8 week streptomycin group had significantly higher hearing thresholds in all frequencies at long term follow-up, and these differences were most prominent in the high frequencies. In children, no differences between the two treatment arms were found. Nephrotoxicity that had been detected in 14% of adults and in 13% of children during treatment, was present in only 2.4% of patients at long term follow-up.

Conclusions

Prolonged streptomycin administration in the adult study subjects caused significant persistent hearing loss, especially in the high frequency range. Nephrotoxicity was also present in both adults and children but appeared to be transient. Streptomycin should be given with caution especially in patients aged 16 or older, and in individuals with concurrent risks for renal dysfunction or hearing loss.     

利福平导致严重血小板减少1例

利福平主要用于结核病的治疗,能引起血小板减少等不良反应。本病例使用利福平后出现严重血小板减少,血小板下降至4×10⁹/L,立即停用利福平并输注血小板后血小板恢复正常。因此,在利福平使用过程中应密切观察病情,监测血常规、肝肾功能等,及时发现不良反应,必要时立即停药,并对血小板明显下降者(<30×10⁹/L)给予补充血小板等治疗。对明确由利福平引起血小板减少者,治疗时应不再使用该药,以避免药物不良事件的发生。     

Evaluation of five antibiotics on larval gut bacterial diversity of Plutella xylostella (Lepidoptera: Plutellidae)

Larvae of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), have rich microbial communities inhabiting the gut, and these bacteria contribute to the fitness of the pest. In this study we evaluated the effects of five antibiotics (rifampicin, ampicillin, tetracycline, streptomycin sulfate and chloramphenicol) on the gut bacterial diversity of P. xylostella larvae. We screened five different concentrations for each antibiotic in a leaf disc assay, and found that rifampicin and streptomycin sulfate at 3 mg/mL significantly reduced the diversity of the bacterial community, and some bacterial species could be rapidly eliminated. The number of gut bacteria in the rifampicin group and streptomycin sulfate group decreased more rapidly than the others. With the increase of antibiotic concentration, the removal efficiency was improved, whereas toxic effects became more apparent. All antibiotics reduced larval growth and development, and eventually caused high mortality, malformation of the prepupae, and hindered pupation and adult emergence. Among the five antibiotics, tetracycline was the most toxic and streptomycin sulfate was a relatively mild one. Some dominant bacteria were not affected by feeding antibiotics alone. Denaturing gradient gel electrophoresis graph showed that the most abundant and diverse bacteria in P. xylostella larval gut appeared in the cabbage feeding group, and diet change and antibiotics intake influenced gut flora abundance. Species diversity was significantly reduced in the artificial diet and antibiotics treatment groups. After feeding on the artificial diet with rifampicin, streptomycin sulfate and their mixture for 10 days, larval gut bacteria could not be completely removed as detected with the agarose gel electrophoresis method.     

Acetobacter methanolicus--a new organism for genetic studies

A new bacterial strain is described belonging to Acetobacter methanolicus species. It is of industrial value as a producer of protein and methanol products. The strain is acidophile and this feature comprises a conspicuous technological advantage. The results of bacteriophage and cell interactions are reported. They might be potentially useful for elaboration of the transduction technique for the strain. The collection of mutants was obtained including those utilizing methanol, having auxotrophic markers as well as streptomycin and rifampicin resistances. The transfer of plasmids RSF1010 and R68 to Acetobacter methanolicus from other bacteria has been demonstrated.     

抗性突变他克莫司高产菌株的选育

研究利用核糖体工程育种方法结合紫外诱变处理产他克莫司链霉菌SIIA-9818,以期筛选得到发酵水平有较大提高的新菌株。首轮采用链霉素抗性筛选,第二轮组合链霉素和利福平抗性结合紫外诱变育种,进一步巩固育种成效。采用链霉素抗性诱变得到突变株T-122,其气生菌丝丰满程度明显好于原对照株,发酵效价提高22.8%;采用组合链霉素和利福平抗性结合紫外诱变T-122,得到多株高产菌株,其中H-493发酵水平较原出发菌株提高82.6%;在50 L发酵罐通过增大搅拌转速,使菌种H-493发酵单位进一步提高31.0%。本方法简单经济,得到的突变株发酵单位显著提高,组分无明显变化,传代稳定。     

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.     

Antibiotic interaction with proteolytic enzymes]

The effect of penicillin, tetracycline, aminoglucozide antibiotics and streptomycin on BAEE-esterase activity of trypsin was studied. It was found that benzylpenicillin in amounts of 50, 100 and 300 mg, ampicillin in an amount of 25 mg, methicillin in an amount of 12 mg and tetracycline in an amount of 2.5 mg as calculated per 1 mg of trypsin had no effect in vitro on the esterase activity of the enzyme. Neomycin, kanamycin and streptomycin in amounts of 5, 10, 100 or 300 mg per 1 mg of trypsin catalyzed splitting of BAEE by trypsin. When the antibiotics were added to the bile, its esterase activity increased. Preliminary intramuscular administration of trypsin and kanamycin to the rats had no effect on the ampicillin levels in the blood serum and brain and did not affect the permeability of the hemato-encephalic barrier as compared to the use of trypsin alone.     

Paradoxical effect of Tween 80 between the susceptibility to rifampicin and streptomycin and the susceptibility to ethambutol and sulfadimethoxine in the Mycobacterium avium-Mycobacterium intracellulare complex.

The susceptibility to rifampicin and streptomycin of the Mycobacterium avium-Mycobacterium intracellulare complex was augmented by the addition of Tween 80 into 7H10 agar medium with OADC, whereas the susceptibility to ethambutol and sulfadimethoxine was either not changed or reduced by the addition of Tween 80. In 7H10 agar medium without OADC, however, susceptibilities to both rifampicin and sulfadimethoxine were reduced by the addition of Tween 80 to the medium. A number of hypotheses are made to explain these phenomena.     

Bacteriostatic and bactericidal activity of antituberculosis drugs against Mycobacterium tuberculosis, Mycobacterium avium-Mycobacterium intracellulare complex and Mycobacterium kansasii in different growth phases.

Bacteriostatic and bactericidal activities of rifampicin, isoniazid, streptomycin, enviomycin and ethambutol against Mycobacterium tuberculosis, Mycobacterium avium--M. intracellulare complex and Mycobacterium kansasii were studied in different growth phases. Bacteriostatic activities of the drugs were similar in different growth phases, except isoniazid. M. tuberculosis was much less susceptible to isoniazid in the lag phase than in the log and the stationary phases. In contrast, bactericidal activity was influenced by the growth phase. M. tuberculosis was killed by isoniazid, streptomycin and rifampicin. The bactericidal activity of isoniazid was strongest. The bactericidal activity of isoniazid and streptomycin was most marked in the log phase. M. avium complex and M. kansasii resisted the bactericidal activity, but some strains of M. avium complex were killed by streptomycin and enviomycin, and the activities of these two drugs were most marked in the lag phase.     

The cost of multiple drug resistance in Pseudomonas aeruginosa

The spread of bacterial antibiotic resistance mutations is thought to be constrained by their pleiotropic fitness costs. Here we investigate the fitness costs of resistance in the context of the evolution of multiple drug resistance (MDR), by measuring the cost of acquiring streptomycin resistance mutations (StrepR) in independent strains of the bacterium Pseudomonas aeruginosa carrying different rifampicin resistance (RifR) mutations. In the absence of antibiotics, StrepR mutations are associated with similar fitness costs in different RifR genetic backgrounds. The cost of StrepR mutations is greater in a rifampicin‐sensitive (RifS) background, directly demonstrating antagonistic epistasis between resistance mutations. In the presence of rifampicin, StrepR mutations have contrasting effects in different RifR backgrounds: StrepR mutations have no detectable costs in some RifR backgrounds and massive fitness costs in others. Our results clearly demonstrate the importance of epistasis and genotype‐by‐environment interactions for the evolution of MDR.