Effect of an interferon preparation on increasing bacterial sensitivity to antibiotics

Under the effect of human leukocytic alpha-interferon-II for injections there was observed an increase in sensitivity of bacteria to benzylpenicillin, ristomycin, novobiocin, streptomycin, kanamycin, monomycin and erythromycin. A higher antibacterial effect of the penicillin and erythromycin was recorded only with respect to initially resistant strains of staphylococci. For the antibiotic resistant strains of staphylococci the MICs of the penicillin and erythromycin decreased on the average 17.8 and 208 times (p less than 0.001) respectively. The interferon had no effect on sensitivity of bacteria to chloramphenicol.     

Effect of antibiotics on development in vitro of hamster pronucleate ova

Antibiotics are commonly added to embryo culture media, but effects on embryo development have not been examined thoroughly. Hamster ova were used to investigate whether penicillin, streptomycin or gentamicin affect embryo development in vitro. Ova were collected 10 h post activation by spermatozoa in vivo and cultured in five treatments: 1) Control: chemically-defined medium HECM-9 with no antibiotics; 2) HECM-9 with 100 IU/mL penicillin; 3) HECM-9 with 50 microg/mL streptomycin; 4) HECM-9 with 10 microg/mL gentamicin and 5) HECM-9 with both 100 IU/mL penicillin and 50 microg/mL streptomycin. Individually, penicillin, streptomycin and gentamicin did not affect embryo development to the 8-cell stage at 58 h post oocyte activation, or morula/blastocyst stages, or blastocysts alone at 82 h post activation. However, when penicillin and streptomycin were both present in the culture medium the percentages of 8-cell embryos at 58 h and blastocysts at 82 h were significantly lower than the control. No antibiotic treatment improved hamster embryo development in vitro. We caution against the use of penicillin and streptomycin together for hamster embryo culture, and show that it is not necessary to include any antibiotics in embryo culture media for up to 72 h if proper sterile technique is used with an oil overlay.     

Mechanism of Resistance to Antibiotic Synergism in Enterococci

Enterococci exhibit two types of resistance to streptomycin. Moderately high-level resistance is observed in most naturally occurring strains and can be overcome by simultaneous exposure to penicillin. In addition, very high-level resistance is found in those strains against which penicillin plus streptomycin fail to produce synergism in vitro. To study the mechanism of streptomycin resistance in enterococci, ribosomes from a wild-type strain and from a highly streptomycin-resistant mutant were isolated, characterized, and studied in an in vitro amino acid incorporation system. The ribosomes from the organism with moderately high-level streptomycin resistance were sensitive to streptomycin in vitro, suggesting that this type of resistance is caused by failure of streptomycin to reach the ribosomes. Very high-level resistance (and lack of penicillin-streptomycin synergism), on the other hand, appears to be due to ribosomally mediated streptomycin resistance.     

Methods for detecting drug-resistant staphylococci in the human body under natural conditions]

Two methods were compared for determination of drug resistant staphylococci on the nasal mucosa of patients, i. e. the routine method for determination of staphylococcal sensitivity to antibiotics and the method of direct plating out of the starting material onto agarized media containing antibiotics. Staphylococci resistant to streptomycin, tetracycline, chloramphenicol, erythromycin, monomycin, axacillin and less frequent to penicillin were found more often with the 2nd method. A method of proportions was developed for testing sensitivity of staphylococci in purulent inflammatory foci of the patients. It provided characterization of the staphylococcal population from the foci by the number of the antibiotic resistant microbial cells.     

Susceptibility of Cheese and Yoghurt Starter Bacteria to Antibiotics

Eight single-strain lactic streptococci, three commercial cheese starters, and six lactic acid bacteria isolated from yoghurt were examined for their susceptibility to penicillin, cloxacillin, tetracycline-hydrochloride and streptomycin. The ranges of the antibiotics causing 50% inhibition of the bacteria were (mug/ml): penicillin, 0.009 to 0.20; cloxacillin, 0.24 to 2.50; tetracycline, 0.09 to 0.60; and streptomycin, 0.35 to 13.0. The average concentrations required to cause 50 and 100% inhibition of the cheese starters were (mug/ml): penicillin, 0.12 and 0.26; cloxacillin, 1.91 and 3.9; tetracycline-hydrochloride, 0.13 and 0.36; and streptomycin, 0.59 and 2.06. All the cocci were about equally susceptible to tetracycline, and all organisms were more resistant to cloxacillin than penicillin. The yoghurt isolates were more resistant to streptomycin and more susceptible to penicillin than the cheese starters. The 2, 3, 5-triphenyltetrazolium chloride test, using Streptococcus thermophilus BC as assay organism, does not detect low levels of streptomycin in milk. However, it is useful in detecting cloxacillin residues.     

Action of mutagenic chemicals on Anacystis nidulans

Summary A mutant strain of the blue-green alga Anacystis nidulans showing a 1000-fold increased resistance to streptomycin over the parental strain was isolated following treatment with diethyl sulphate. The mutant strain was found to show profuse filamentation, partial requirement of streptomycin for pigment production, and greater resistance to ultraviolet radiation. It also showed greater sensitivity to dimethyl sulphate than the parental strain. It seems that the streptomycin-resistant strain is a composite one comprising at least four kinds of mutations, namely streptomycin-resistance, filamentation, u.v.-resistance and partial dependence on streptomycin for pigment accumulation. Further. the streptomycin-resistant mutant seems nuclear rather than extra-nuclear in nature.Treatment with diethyl sulphate also conferred a slight increase in resistance to penicillin in this alga.     

Rumen Fungi and Forage Fiber Degradation

The role of anaerobic rumen fungi in in vitro forage fiber degradation was determined in a two forage × two inoculum source × five treatment factorial design. Forages used as substrates for rumen microorganisms were Coastal bermuda grass and alfalfa; inoculum sources were rumen fluid samples from a steer fed Coastal bermuda grass hay or alfalfa hay; treatments were whole rumen fluid (WRF), WRF plus streptomycin (0.2 mg/ml of rumen fluid) and penicillin (1.25 mg/ml of fluid), WRF plus cycloheximide (0.5 mg/ml of fluid), WRF plus streptomycin, penicillin, and cycloheximide, and McDougall buffer. Populations of fungi as shown by sporangial development were greater on bermuda grass leaves than on alfalfa leaflets regardless of inoculum source. However, endogenous fungal populations were greater from the alfalfa hay inoculum. Cycloheximide inhibited the fungi, whereas streptomycin and penicillin, which inhibit bacterial populations, resulted in an increase in numbers of sporangia in the alfalfa inoculum, suggesting an interaction between bacteria and fungi. Bacteria (i.e., WRF plus cycloheximide) were equal to the total population in degrading dry matter, neutral-detergent fiber (NDF), acid-detergent fiber (ADF), and cellulose for both inocula and both forages. Degradation of dry matter, NDF, ADF, and cellulose by anaerobic fungi (i.e., WRF plus streptomycin and penicillin) was less than that due to the total population or bacteria alone. However, NDF, ADF, and cellulose digestion was 1.3, 2.4, and 7.9 percentage units higher, respectively, for bermuda grass substrate with the alfalfa versus bermuda grass inoculum, suggesting a slight benefit by rumen fungi. No substantial loss of lignin (72% H₂SO₄ method) occurred due to fungal degradation. The most active fiber-digesting population in the rumen was the bacteria, even when streptomycin and penicillin treatment resulted in an increase in rumen fungi over untreated WRF. The development of large numbers of sporangia on fiber may not indicate a substantial role as digesters of forage.     

Susceptibility of various purple and green sulfur bacteria to different antimicrobial agents

Abstract Several purple and green sulfur bacteria (genera Chromatium, Thiocapsa and Chlorobium ) were tested for their sensitivity to different antimicrobial agents by a disc diffusion assay, using thioacetamide as a source of hydrogen sulfide for plate growth. Chlorobium limicola strains were more sensitive to amoxicillin, erythromycin and nalidixic acid, whereas gentamicin and netilmicin were more active against the purple bacteria tested. None of the organisms were sensitive to oxacillin and trimethoprim + sulfamethoxazole. The critical concentrations at the edge of the inhibition zone were also calculated for three organisms and the antimicrobials colistin, mitomycin C, penicillin G, rifampicin, and streptomycin. The results obtained suggest that colistin, mitomycin C, penicillin G would provide selective conditions against the growth of Chlorobium limicola strains, while streptomycin and other aminoglycoside antibiotics would select against purple bacteria.     

Subacute bacterial endocarditis; a report on 57 patients treated with massive doses of penicillin

Fifty-seven patients with subacute bacterial endocarditis were treated with doses of penicillin varying from 500,000 to 20,000,000 units per day. Diagnosis was confirmed in some cases by growths on blood culture, in others by postmortem examination. In those cases in which the diagnosis was established by blood culture, the in vitro sensitivity of the organism to penicillin was determined and penicillin then was administered by continuous intramuscular infusion in a dosage calculated to produce blood levels of penicillin four to five times that required for in vitro inhibition. Penicillin was given for a period of 21 days, and blood cultures were made periodically during and after treatment. Of the 57 patients, 38 were cured (66.7 per cent), and 19 died (33.3 per cent). Of the 19 who died, three did so within 48 hours of hospitalization and seven died despite adequate treatment. Of these seven, three died of cerebral emboli, two because of resistance to penicillin and streptomycin, one because of congestive heart failure, and one of undetermined cause. The remaining nine who died were considered to have been inadequately treated in that there was (1) failure to obtain sensitivity, (2) inadequate dossage of penicillin, (3) delay in starting treatment, or (4) failure to recognize mixed infections. There were five patients with repeatedly sterile blood cultures during life. In all of these cases, streptococcus viridans was recovered at postmortem examination. In an attempt to determine how long therapy should justly be withheld in patients with repeatedly sterile blood cultures, 140 cases of subacute bacterial endocarditis in which positive blood cultures had been obtained were reviewed. From the review it was determined that if blood cultures taken during the first two days are reported sterile, the chance of subsequent cultures proving positive is minimal. Therefore, for patients in whom the diagnosis seems otherwise obvious, delaying treatment for more than two days is not justified even though the blood culture be sterile. In cases in which blood cultures are repeatedly sterile, a dosage of 6,000,000 to 10,000,000 units of penicillin daily for 21 days is advisable.High bacterial resistance to penicillin and streptomycin was found in four fatal cases. In one of these, the infecting organism was streptococcus viridans, and in three it was staphylococcus albus. There was one patient with penumococcal meningitis complicated by unrecognized streptococcal viridans bacterial endocarditis.     

Intracellular production of Brucella L forms . II. Induction and survival of Brucella abortus L forms in tissue culture

Hatten, Betty A. (The University of Texas Southwestern Medical School, Dallas), and S. Edward Sulkin. Intracellular production of Brucella L forms. II. Induction and survival of Brucella abortus L forms in tissue culture. J. Bacteriol. 91:14-20. 1966.-Intracellular survival of altered brucellae, possibly L forms, was not greatly affected by penicillin or streptomycin in concentrations ranging from 5.0 to 40 mug/ml, but a combination of these two antibiotics (2.5 to 20 mug/ml each) reduced the number of positive L-form cultures. Tetracycline (2.0 mug/ml) decreased the number of positive L-form cultures at about the same rate as combinations of the higher concentrations of penicillin and streptomycin. Various concentrations of tetracycline (0.1 to 2.0 mug/ml) with 5.0 mug/ml of penicillin or streptomycin significantly reduced the number of positive L-form cultures. L forms were recovered for several days after elimination of bacteria from the cultures by all of the antibiotics tested. L-form production was not dependent upon the presence of antibiotics in the culture medium, but they were recovered in greater numbers when bacteria were still present in the hamster kidney cells. Addition of thallium acetate to infected cells (at varying intervals of time after infection) to control bacterial growth and conversion to the L phase during cellular disintegration decreased the number of positive L-form cultures obtained over a 10-day period. Comparison of the antibiotic sensitivity of bacteria recovered from infected tissue culture cells with the stock strain of Brucella abortus indicated that some resistance to penicillin and tetracycline had developed. A marked resistance to streptomycin was observed in those bacteria recovered from cells maintained in the presence of this antibiotic.     

SUBACUTE BACTERIAL ENDOCARDITIS—A Report on 57 Patients Treated with Massive Doses of Penicillin

Fifty-seven patients with subacute bacterial endocarditis were treated with doses of penicillin varying from 500,000 to 20,000,000 units per day. Diagnosis was confirmed in some cases by growths on blood culture, in others by postmortem examination. In those cases in which the diagnosis was established by blood culture, the in vitro sensitivity of the organism to penicillin was determined and penicillin then was administered by continuous intramuscular infusion in a dosage calculated to produce blood levels of penicillin four to five times that required for in vitro inhibition. Penicillin was given for a period of 21 days, and blood cultures were made periodically during and after treatment.Of the 57 patients, 38 were cured (66.7 per cent), and 19 died (33.3 per cent).Of the 19 who died, three did so within 48 hours of hospitalization and seven died despite adequate treatment. Of these seven, three died of cerebral emboli, two because of resistance to penicillin and streptomycin, one because of congestive heart failure, and one of undetermined cause. The remaining nine who died were considered to have been inadequately treated in that there was (1) failure to obtain sensitivity, (2) inadequate dossage of penicillin, (3) delay in starting treatment, or (4) failure to recognize mixed infections.There were five patients with repeatedly sterile blood cultures during life. In all of these cases, streptococcus viridans was recovered at postmortem examination. In an attempt to determine how long therapy should justly be withheld in patients with repeatedly sterile blood cultures, 140 cases of subacute bacterial endocarditis in which positive blood cultures had been obtained were reviewed. From the review it was determined that if blood cultures taken during the first two days are reported sterile, the chance of subsequent cultures proving positive is minimal. Therefore, for patients in whom the diagnosis seems otherwise obvious, delaying treatment for more than two days is not justified even though the blood culture be sterile. In cases in which blood cultures are repeatedly sterile, a dosage of 6,000,000 to 10,000,000 units of penicillin daily for 21 days is advisable.High bacterial resistance to penicillin and streptomycin was found in four fatal cases. In one of these, the infecting organism was streptococcus viridans, and in three it was staphylococcus albus. There was one patient with penumococcal meningitis complicated by unrecognized streptococcal viridans bacterial endocarditis.     

Effect of chymotrypsin on the urinary excretion of antibiotics in rabbits]

The effect of cymotrypsin on excretion of penicillin, methicillin, oxacillin, streptomycin and gentamycin with urine including the kidney clearance was studied on rabbits. It was found that the enzyme introduced intramuscularly in a dose of 20 mg/kg increased excretion of penicillin, methicillin, oxacillin and gentamycin by 37, 24, 26 and 16 per cent respectively. The only exclusion was streptomycin. Chymotrypsin increased the kidney clearance of penicillin, methicillin, oxacillin, streptomycin and gentamycin by 1.7, 1.9, 2.2, 1.2 and 1.5 times respectively.     

Streptomycin retards the phenotypic maturation of chick myogenic cells

Summary As part of an effort to optimize conditions required for the complete maturation of muscle cells in vitro, we have investigated the effects of the antibiotics penicillin, streptomycin, and Fungizone (amphotericin B) on the development of cultured chick embryo skeletal muscle. It is shown that even low dosages of streptomycin, but not penicillin or Fungizone, retard protein synthesis and accumulation in these cultures. Myosin accumulation was also reduced and the appearance of striations in fused cells was delayed in myotubes formed in medium containing streptomycin. Additional data suggest that this overall retardation of myogenesis is due to the influence of streptomycin on maturing myotubes rather than early proliferation and cell fusion. These results are discussed with regard to recent efforts to promote the full maturation of muscle cells grown in culture. This research was supported by National Institutes of Health Grant NS 155882 and a Task Force on Drug Development Research Contract from The Muscular Dystrophy Association.     

THE USE OF AEROSOL PENICILLIN AND STREPTOMYCIN IN BRONCHOPULMONARY INFECTIONS

Three hundred patients with subacute or chronic non-tuberculous bronchopulmonary disease were given aerosol therapy, chiefly penicillin and more recently penicillin combined with streptomycin. The result showed that the inhalation of these antibiotics is a useful procedure in the treatment of tracheobronchitis, either subacute or protracted, or in association with bronchial asthma, bronchiectasis or pulmonary emphysema. The method of administration is simple.     

Quantitative antibiotic sensitivity pattern ofAcinetobacter strains

Seventy-eightAcinetobacter strains (37A. lwoffii, 22A. haemolysans and 19A. anitratus) were tested for antibiotic sensitivity with the plate incorporation method. TheA. anitratus strains were distinctly less sensitive to penicillin, chloramphenicol, oxytetracyclin and nitrofurantoin than theA. lwoffii andA. haemolysans strains. Sensitivity patterns to streptomycin and erythromycin were similar for the three species.     

4种抗生素对蚯蚓-污泥系统细菌群落结构的影响

蚯蚓可摄食污泥中的有机物,其肠道微生物群落在其分解过程中起着主要的作用。利用赤子爱胜蚓(Eisenia foetida)和人工湿地基质构建蚯蚓-污泥系统,添加氯霉素、四环素、链霉素和青霉素4种抗生素,研究不同抗生素对污泥和蚓粪的细菌群落结构的影响。采用高通量测序技术比较分析污泥和蚓粪的细菌多样性及群落结构变化。结果表明,外加抗生素能够导致污泥的Chao1和ACE指数降低,同时降低拟杆菌门和变形菌门的相对丰度,加入氯霉素和青霉素会增加厚壁菌门的相对丰度,降低酸杆菌门、放线菌门和绿弯菌门的相对丰度,加入四环素和链霉素则与之相反。蚓粪样品中,添加氯霉素和链霉素导致Chao1和ACE指数降低,而添加四环素和青霉素则导致Chao1和ACE指数升高,外加抗生素可降低拟杆菌门的相对丰度,增加放线菌门、变形菌门和疣微菌门的相对丰度。主成分分析(PCA)和聚类分析表明,氯霉素和青霉素对污泥细菌群落影响作用相似,四环素与链霉素效果类似;氯霉素对蚓粪群落结构的影响小于其他抗生素。研究结果显示,抗生素可影响污泥和蚓粪的细菌多样性及群落结构,不同抗生素对污泥和蚓粪的影响程度存在差异。     

Various methods of using lincomycin for treating acute and chronic hematogenic osteomyelitis in children]

Comparative data on the treatment of 209 children with acute and chronic hematogenic osteomyelitis are presented; 128 patients hospitalized before 1974 were treated with antibiotics, mainly penicillin and streptomycin without sensitivity testing. From 1974 81 children were treated with lincomycin; 80 per cent of the isolates were sensitive to this antibiotic. In lincomycin therapy the method of electrophoresis on the disease focus, intrabone administration of the drug and administration of the drug into the bone cavity together with the blood clot during surgical interventions in cases with chronic hematogenic osteomyelitis were used. A marked decrease in the rate of the chronic forms of the disease was registered (from 77.2 to 8.8 per cent).     

Antibiotic penetration through the blood-brain barrier in rats and the effect on this process of proteolytic enzymes]

Penetration of penicillin, ampicillin, oxacillin, tetracycline, streptomycin and gentamycin through the hemato-encephalic barrier in rats and effect of proteolytic enzymes on the above process were studied comparatively. The levels of penetration to the brain were highest for ampicillin, then followed penicillin, tetracycline, oxacillin, streptomycin and gentamycin. Preliminary intramuscular administration of trypsin and chimotrypsin (10 mg/kg) to the animals had no effect on permeability of the hemato-encephalic barrier for the antibiotics tested, except penicillin. Higher levels of the antibiotics in the brain tissue may be explained by higher antibiotic blood levels under the effect of proteolytic enzymes.     

Improved Method for Axenizing Blepharisma by Means of Antibiotics

Synopsis.
A simplified method for obtaining axenic cultures of Blepharisma involves the use of penicillin, streptomycin, and tetracycline. Cytologic examination disclosed no significant effect of these antibiotics on the structure of the ciliates.     

葡萄糖存在下选择性抑菌剂对土壤氮素转化的影响

采用2种氮源并分别加入选择性微生物抑制剂进行室内培养,通过测定样品中NH₄⁺-N和NO₃^--N及土壤中氨基葡萄糖和胞壁酸含量,研究土壤微生物氮素固持时间特征及其相对贡献.结果表明,加入青链霉素明显地降低了NH₄⁺-N的转化速率,且影响远大于真菌抑制剂放线菌酮;氨基葡萄糖和胞壁酸的相对比例急剧增加,而后趋于平衡;加入放线菌酮后NO₃-N转化速率持续下降,氨基葡萄糖的合成受到抑制,但加入细菌抑制剂青链霉素对其转化无显著影响.培养初期,细菌在葡萄糖存在下能快速固持NH₄⁺-N和NO₃^--N,并以NH₄⁺-N为首选氮源;培养后期,氮转化主要为真菌所推动,且真菌对NO₃^--N的利用能力显著大于细菌.