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At least 19 recordsLinked to original sources

Chemotherapy for giardiasis: randomized clinical trial of bacitracin, bacitracin zinc, and a combination of bacitracin zinc with neomycin.

This study describes a prospective, randomized, clinical trial in patients infected with the protozoa Giardia lamblia. Patients received a 10-day treatment with twice a day doses of either 120,000 U (USP) of bacitracin zinc, 120,000 U (USP) of bacitracin, 120,000 U (USP) of neomycin, or 60,000 U (USP) of bacitracin zinc and 60,000 U (USP) of neomycin. At the first assessment (day 11), all 21 subjects (100%) treated with bacitracin zinc had ceased to show Giardia parasites in their stools compared with 19 (95%) of 20 receiving bacitracin, 20 (90.9%) of 22 subjects receiving neomycin, and 17 (89.5%) of 19 subjects receiving bacitracin zinc plus neomycin. During the two-week follow up period, one (5.3%) of the 19 subjects examined who received bacitracin zinc experienced a recurrence compared with one (6.7%) of 15 receiving bacitracin, one (5.0%) of 20 receiving neomycin, and 0 (0%) of 14 receiving the combination treatment. Final cure rates of 94.7% for bacitracin zinc, 87.5% for bacitracin, 86.4% for neomycin, and 87.5% for bacitracin zinc plus neomycin were obtained. No synergistic activity was noted between bacitracin zinc and neomycin. Side effects were generally limited to nausea, abdominal discomfort, and diarrhea in a small number of patients.

Adolescent↗

Sporulation of a bacitracin-sensitive mutant of Bacillus licheniformis is self-inhibited by bacitracin.

A mutant of Bacillus licheniformis (BLU166) sensitive to its own antibiotic bacitracin was isolated and the mutation bcr-l was mapped close to the bacitracin synthetase genes. The sensitivity was shown to be specific for bacitracin. Two further bacitracin-sensitive strains were constructed, one (BLU171) with normal ability to synthesize bacitracin, and one (BLU170) a bacitracin non-producer. In addition to an increased sensitivity of growing cells to bacitracin, sporulation of the mutant strain BLU171 was self-inhibited by bacitracin. It is concluded that (1) there might exist at least two levels of resistance to bacitracin; (2) mutation bcr-1 affects a 'structural' component, which may protect the sensitive reaction of cell-wall biosynthesis; (3) sporulation is affected to a greater extent by bacitracin than vegetative growth; and (4) synthesis of bacitracin is independent of the presence of this resistance mechanism since the sensitive mutant produces similar amounts of the antibiotic to the wild-type strain.

Bacillus↗

Growth and performance of broiler breeders fed bacitracin methylene disalicylate and zinc bacitracin.

Day-old Cobb broiler breeder pullets were randomly allotted into 20 floor pens where they were brooded and reared to 23 wk of age. Eight pens received a control diet containing no growth promotant. The other 12 were fed 55 mg of bacitracin methylene disalicylate/kg of diet. Males were reared separately on the control diet. Pullets were full-fed for the first 8 wk of life, then placed on a skip-a-day program with breeder-recommended feed allocations. At 23 wk of age bird numbers were reduced to 26 females per pen, three males added, and diets changed to the layer regimen. Levels of 0, 27.5, 55, or 110 mg/kg of zinc bacitracin were each assigned to five pens with factorial attention to growing treatment. Layer treatments were continued for 280 days. No significant differences were associated with the feeding of bacitracin methylene disalicylate among body weight or mortality data summarized at 8 and 23 wk. Eight-week feed efficiency was also not affected. In the laying phase, 110 mg/kg of zinc bacitracin significantly improved egg production and fertility over the unsupplemented controls. Hatch of fertile eggs, overall hatchability, and the number of chicks per pen were all significantly improved by 27.5 mg/kg of zinc bacitracin. Higher drug levels supported no additional improvement. Feed efficiency, mortality rate, and final body weight were not significantly influenced by any level of supplementation. No effect of grower treatment upon subsequent layer performance was noted.

Animal Feed↗

[Effect of bacitracin and other drugs on the synthesis of the antibiotic itself (bacitracin) by a Bacillus licheniformis culture].

The type and level of resistance of Bac. licheniformis 1001 to the antibiotic produced by it, i. e. bacitracin and the effect of bacitracin and some other drugs on the culture variation with respect to the feature of the antibiotic production were studied. It was found that strain 1001 possessed an inducible resistance to its own antibiotic. In addition, a cross inducible resistance to bacitracin and penicillin was observed. The mutations of the resistance to bacitracin, as well as streptomycin, rifampicin and sulfaethidole had no effect on bacitracin production by strain 1001.

Bacillus↗

A comparison of the performance of bacitracin-incorporated chocolate blood agar with chocolate blood agar plus a bacitracin disk in the isolation of Haemophilus influenzae from sputum.

The lack of selectivity of chocolated blood agar (CBA), routinely used for the isolation of Haemophilus influenzae, may lead to masking of the growth of H. influenzae due to overgrowth of competing flora. Bacitracin can be used as a selective agent, either incorporated into the medium or applied to the medium in a filter paper. However, neither method has been evaluated or compared in a large study. Sputum samples (1990) were examined in four laboratories and the isolation rates of H. influenzae on chocolated blood agar with bacitracin added to the medium (BCA) and chocolated blood agar (CBA) with a bacitracin disk were compared. A plain blood agar plate was also inoculated to facilitate the isolation of Streptococcus pneumoniae so that its effects on the isolation of H. influenzae could be assessed. No significant difference was found between the isolation rates of H. influenzae on BCA and CBA with a bacitracin disk, although competing flora was greatly reduced and quantity of growth of H. influenzae increased on BCA. The presence of S. pneumoniae did not affect the isolation of H. influenzae in this study.

Anti-Bacterial Agents↗

Amplification of bacitracin transporter genes in the bacitracin producing Bacillus licheniformis.

We have amplified the previously cloned and sequenced genes of the bacitracin exporter (bcr), a member of the ATP-binding transport protein family, within the chromosome of the bacitracin producing Bacillus licheniformis. Amplification of the transporter genes was followed by greatly increased bacitracin resistance. Antibiotic production was enhanced at a low level of bcr genes amplification. An enlarged increase in the copy number of the bcr genes negatively affects the overall growth of bacteria.

ATP-Binding Cassette Transporters↗

The role of the bacitracin ABC transporter in bacitracin resistance and collateral detergent sensitivity.

The bacitracin resistance of Bacillus licheniformis, a producer of bacitracin, is mediated by the ABC transporter Bcr. Bacillus subtilis cells carrying bcr genes on high-copy number plasmids developed collateral detergent sensitivity, as did human cells with overexpressed multidrug resistance P-glycoprotein. Resistance against bacitracin and sensitivity of resistant cells to detergents were shown to be inseparable phenomena associated with the membrane part of Bcr transporter, namely protein BcrC. A fused protein, consisting of ATP-binding protein BcrA and membrane component BcrC was constructed. It resembled a half molecule of P-glycoprotein and was capable of providing a significant degree of antibiotic resistance and detergent sensitivity.

ATP-Binding Cassette Transporters↗

Resistance to bacitracin as modulated by an Escherichia coli homologue of the bacitracin ABC transporter BcrC subunit from Bacillus licheniformis.

A small open reading frame from the Escherichia coli chromosome, bcrC(EC), encodes a homologue to the BcrC subunit of the bacitracin permease from Bacillus licheniformis. We show that disruption of the chromosomal bcrC(EC) gene causes bacitracin sensitivity and, conversely, that BcrC(EC) confers bacitracin resistance when expressed from a multicopy plasmid.

ATP-Binding Cassette Transporters↗

Glucose-sucrose-potassium tellurite-bacitracin agar, an alternative to mitis salivarius-bacitracin agar for enumeration of Streptococcus mutans.

An agar medium for selective recovery and enumeration of Streptococcus mutans was developed as an alternative to mitis salivarius-bacitracin (MSB) agar. Combinations of dyes, antibiotics, and tellurite were added to a nonselective medium which, because of its sucrose content, allowed easy recognition of S. mutans colonies. Candle jar incubation for 2 days, by comparison with anaerobic incubation, reduced background flora but did not diminish S. mutans recoveries from clinical samples. Quantitative comparisons were made of the simultaneous recoveries of a number of authentic S. mutans serotype representatives and fresh clinical isolates, using various glucose-sucrose-potassium tellurite-bacitracin (GSTB) formulations and mitis salivarius, MSB, and blood agars. Mitis salivarius counts were not detectably different from blood counts, but counts on MSB were distinctly lower. A formulation of the new medium containing 5% glucose 5% sucrose, 0.001% potassium tellurite, 0.3 U of bacitracin per ml (hence GSTB), and 2% agar gave recoveries nearly equal to those on mitis salivarius agar and much greater than those on MSB. The medium yielded readily recognized S. mutans colonies and facilitated detection of intracellular polysaccharide formers upon flooding with I2 reagent. Freshly isolated serotype c, E, and f colonies could often be distinguished from serotype d and g colonies, a distinction made reliable by testing for intracellular polysaccharide. A study of 300 salivary samples revealed GSTB to give significantly higher recoveries than MSB. About 72% of all samples were substantially underestimated for S. mutans with MSB, and 6.7% of samples were falsely negative for S. mutans with MSB. Recovery of background flora on GSTB was as low or lower than on MSB, and both types of agar could be stored for at least 9 weeks without notable change of selectivity. Thus, GSTB agar appears to be simple and reliable to use and requires no anaerobic incubation. Caution is voiced about interpretation of data previously reported which evaluated S. mutans on MSB agar.

Agar↗

Bacitracin and a bacitracin-zinc complex damage DNA and carbohydrate in the presence of iron and copper salts.

The antibiotic bacitracin binds metal ions such as zinc, copper and iron, and is often prepared for clinical and veterinary use as a zinc complex to enhance stability. Here, we show that bacitracin and its zinc complex are able to reduce copper and iron salts with the formation of hydrogen peroxide. This results in damage to the bacitracin molecule and the release of some oxidising radicals into free solution that attack detector molecules such as deoxyribose and DNA. Damage to deoxyribose and DNA can be detected by the formation of thiobarbituric acid-reactive material and this damage can be protected against by the addition of scavengers of the hydroxyl radical implicating the OH radical in the degradation observed.

Bacitracin↗

Improved high-performance liquid chromatographic method for polypeptide antibiotics and its application to study the effects of treatments to reduce microbial levels in bacitracin powder.

Improvements were made in the high-performance liquid chromatographic (HPLC) method to obtain baseline separation of chromatographic peaks of structurally similar polypeptide components in bacitracin. The improved method uses a 30-cm-long stainless-stell column packed with muBondapak C18. The theoretical plates of the column are approximately 140,000 per meter for the bacitracin A peak. The resolution function between bacitracins B1 and B2 and that between bacitracins A and B2 have been improved 418 and 225%, respectively. The components of bacitracin, bacitracins A, B, C, D, E, F, and G, were fractionated by the countercurrent distribution technique. These components, together with Compound X, a compound separated on a carboxymethylcellulose column, and bacitracin F, obtained by degrading bacitracin A sample at neutral pH, were used to identify peaks in the HPLC chromatogram. Effects of processing methods used to reduce microbial contamination levels in bacitracin powders were evaluated. Heat treatment caused a significant loss of antimicrobial activity (35% reduction), bacitracins A, B1, and B2 were reduced by 37, 22, and 21%, respectively. A significant increase (2.8 times) of bacitracin F, an oxidative degradation compound, was show. Irradiation by 60Co at 1.8 Mrad caused no loss of potency nor change in any of the bacitracin components. Ethylene oxide treatment, on the other hand, caused considerable (46%) reduction of potency. Substantial reduction of areas under the peak of bacitracins A, B1, and B2 (50, 24 and 37%, respectively) were noted. The chromatograms showed numerous unresolved peaks around bacitracins A, B1 and B2,; however, no significant increase in the bacitracin F peak, nor appearance of non-UV absorbing peaks were observed. Peptide antibiotics of the polymyxin group, circulin, colistin, and polymyxin, were also analyzed using the muBondapak C18 column with a linear-gradient elution. A UV monitor was used for polymyxin. A moving-wire flame ionization detector was used to monitor circulin and colistin. A sample of polymyxin, circulin, and colistin may be analyzed in less than 20 min of chromatographic time.

Anti-Bacterial Agents↗