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PubMed1983

Proteinase affinity chromatography on bacitracin-Sepharose.

Antibiotic-cyclopeptide bacitracin covalently bound to Sepharose proved to be an efficient general ligand for affinity chromatography of aspartyl, serine, and metalloproteinases from various sources. The yields of purified enzymes varied from 50 to 180%. New experimental data extend the application of bacitracin-Sepharose for affinity chromatography of cysteine proteinases--papain, bromelain, and ficin. Hence, bacitracin acts as a ligand which more or less efficiently binds proteinases that belong to all the main classes of these enzymes. Bacitracin, being a weak proteinase inhibitor of broad specificity, interacts with the substrate-binding sites of proteinases, which explains its efficiency as a ligand.

Affinity Labels↗
PubMed1983

[Participation of temperate phages LP52 and BL20 in the control of bacitracin synthesis in Bacillus licheniformis].

The synthesis of the antibiotic bacitracin in lysogenic and nonlysogenic strains of Bacillus licheniformis 1001 and ATCC10716 has been studied. The antibiotic activity was shown to be about 20% less in lysogens, as compared to nonlysogens. However, the level of bacitracin production was completely restored when temperate bacteriophages BL20 and LP52 were reintroduced into the nonlysogenic strains by virtue of genetic transformation with DNA from lysogenic strains or by transduction with LP52. This may indicate that both phages take part in control of the synthesis of bacitracin. For the time being, the mechanism of regulation is not known. It is likely to be either direct (provided that prophage DNA contains "bacitracin" genes), or indirect.

Bacillus↗
PubMed1980

Evaluation of methanol extraction for determination of bacitracin in feeds.

Five laboratories evaluated methanol extraction for the determination of zinc and methylene disalicylate (MD) bacitracn in swine and poultry feeds at 100 g/ton and 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The kind of bacitracin or type of feed did not significantly affect results.

Animal Feed↗
PubMedDate not supplied

Liquid chromatographic analysis of bacitracin methylene disalicylate in feed.

Because of its peptide structure, bacitracin is not chemically distinct from many matrixes such as feeds or residue samples. Thus, bacitracin must be isolated from the matrix components or chemically altered to form a distinct component. Because of the complexity of this problem, bacitracin is still analyzed almost exclusively by microbiological methods. However, advances in solid-phase extraction has made sample isolation from the matrix much more practical. In this investigation both strong-cation exchange and C8 columns were used to isolate bacitracin for liquid chromatographic (LC) analysis. Results of both LC and microbiological analyses are compared.

Animal Feed↗
PubMed1966

Lethal gram-negative bacterial superinfection in Guinea pigs given bacitracin.

Farrar, W. Edmund, Jr. (Walter Reed Army Institute of Research, Washington, D.C.), Thomas H. Kent, and Van B. Elliott. Lethal gram-negative bacterial superinfection in guinea pigs given bacitracin. J. Bacteriol. 92:496-501. 1966.-Oral administration of a single dose of bacitracin (either 2,000 or 10,000 units) was lethal to more than 80% of guinea pigs. Within the first 12 hr, there was a 2,000-fold fall in the number of gram-positive organisms in the cecum. An increase in the number of coliform bacteria in the cecum was demonstrable within 6 hr, and, by 48 hr, these organisms had increased from the normal level of less than 100 per gram to approximately 1 billion per gram. The changes in intestinal bacterial flora were associated with development of a severe cecitis, mild ileitis, and acute regional lymphadenitis. Bacteremia, primarily due to coliform bacteria, was demonstrated in approximately 40% of the animals killed between 72 and 96 hr after administration of bacitracin. Development of this disease syndrome was suppressed by the administration of neomycin and polymyxin B, nonabsorbable antibiotics effective against coliform bacteria. The lethal disease produced by bacitracin in the guinea pig is similar to that produced by penicillin.

Journal Article↗
PubMed1965

THE SYNTHESIS AND BACITRACIN-CATALYSED HYDROLYSIS OF ARYL ESTERS OF N-ACYLAMINO ACIDS.

1. A new method for synthesizing aryl esters of N-acylamino acids is described. The unsymmetrical anhydride resulting from the interaction of an N-acylamino acid and diphenylketen is allowed to react with a phenol. Cleavage of the anhydride by the phenol usually occurs in the desired direction. 2. Bacitracin has been examined as an enzyme model by determining its catalytic activity towards the hydrolysis of aryl esters. In general, it is less effective than imidazole. The variation of the catalytic constant with pH, together with other evidence, suggests that the histidine residue in bacitracin is the effective catalytic centre. 3. The stereoisomers of N-methoxycarbonylalanine p-nitrophenyl ester were hydrolysed at the same rate, but bacitracin was stereoselective towards the stereoisomers of the corresponding phenylalanine derivative.

Amino Acids↗
PubMed1965

ISOLATION OF L FORMS FROM GROUP A STREPTOCOCCI EXPOSED TO BACITRACIN.

Rotta, Jiri (Washington University School of Medicine, St. Louis, Mo.), Walter W. Karakawa, and Richard M. Krause. Isolation of L forms from group A streptococci exposed to bacitracin. J. Bacteriol. 89:1581-1585. 1965.-L forms were obtained from group A streptococci by exposure to bacitracin on gradient plates, although novobiocin was ineffective in this respect. Subcultures of these L forms had morphological and bacteriological properties similar to those obtained with penicillin. M protein was detected in L-form colony smears by immunofluorescent staining with type-specific conjugate. The L forms were not stained with group-specific conjugate. Parallel precipitin tests performed with extracts from a heavy growth of L forms on agar confirmed these findings. Thus, the L forms obtained with bacitracin continue to produce M protein but are devoid of the group-specific carbohydrate which is a major component of cell-wall structure.

Bacitracin↗
PubMed1994

Primary structural confirmation of components of the bacitracin complex.

The bacitracin antibiotic peptide complex has been analyzed using liquid chromatography in conjunction with ion spray tandem mass spectrometry and multiple reaction monitoring techniques. Fragmentation patterns were determined from the product ion spectrum of bacitracin A (mol. wt 1421.8 Da), a compound of well-established structure. Primary structural information has been determined for seven minor components of the bacitracin complex with regard to the extent of amino acid substitution taking place.

Amino Acid Sequence↗
PubMed2003

Capillary electrophoretic study of the binding of zinc(II) ion to bacitracin A1 in water-2,2,2-trifluoroethanol.

Binding of Zn(2+) to bacitracin A(1) was studied by capillary electrophoresis in water/2,2,2-trifluoroethanol (70/30 v/v) at different apparent pH values in order to estimate the association constant of metal, the acidic dissociation constants and the Stokes radii of both free and bounded peptide in apolar environment. The Stokes radii of the free peptide species were compared with those in aqueous solution, as obtained in a recent study performed by our group, indicating that apolar environment stabilizes bacitracin A(1) in a conformational structure with the lateral chain of apolar amino acids exposed on the external surface. This conformation of the macrocyclic dodecapeptide is ready to interact with Zn(2+) ion, as pointed out by the strong increase of the association constant measured in water/2,2,2-trifluoroethanol with respect to the value obtained in aqueous solution. In addition, whereas Zn(2+) ion binding in aqueous solution provides a sensible reduction of peptide Stokes radius, no sensible variations following to ion binding were observed in hydro-organic solution. The present results suggest that the apolar environment, rather than the metal ion binding, could be responsible for the conformational transition that brings bacitracin A(1) towards its biologically active structure.*

Bacitracin↗
PubMed2004

Different binding thermodynamics of Ni2+, Cu2+, and Zn2+ to bacitracin A1 determined by capillary electrophoresis.

Thermodynamics of the binding of Ni(2+), Cu(2+) and Zn(2+) to bacitracin A(1) was studied by capillary electrophoresis measuring the peptide effective mobility at different pH in the presence of increasing concentration of the three ligands. The affinity follows the order Ni(2+) > Cu(2+) > Zn(2+), with association constant values of (2.3 +/- 0.1)x10(4), (4.9 +/- 0.2)x10(3), and (1.5 +/- 0.1)x10(3) M(-1), respectively. The only model able to rationalize mobility data implies that metal ion binds to the P(0) peptide form. Moreover, mobility values indicated a change of bacitracin A(1) acidic properties on Ni(2+) and Cu(2+) binding, with a shift of the pK(a) of N-terminal Ile-1 from 7.6 to about 5 and of the pK(a) of the delta-amino group of D-Orn-7 from 9.7 to about 7. Even though on Zn(2+) binding a shift of the N-terminal Ile-1 pK(a) was observed, restrictions in the pH range suitable for investigation, due to precipitation phenomena, did not allow establish if the shift of D-Orn-7 lateral chain pK(a) also occurred. Nonetheless, if present, the shift should be limited to the 7.8-9.7 range. Mobility data indicated that the Stokes radius of the complexes is ca. 3 A lower than that of the free peptide. The present results indicate that metal-ion binding to bacitracin A(1) is more complex than previously assumed.

Bacitracin↗
PubMed2003

Influence of molecular dipoles on human skin permeability: Use of 6-ketocholestanol to enhance the transdermal delivery of bacitracin.

In the present work, we report the possibility of modifying the electrostatic properties of the skin by treating human epidermis with compounds whose structures possess a large molecular dipole moment. Data are presented showing that such a modification can be used to enhance dermal drug delivery. Inclusion of such compounds in biological membranes affects the so-called membrane dipole potential, an electrical potential originating from molecular dipoles present on the lipid molecules. Modifications in the magnitude of this potential are known to affect the interaction of hydrophobic ions and peptides with model membranes. Using fluorescein-labeled bacitracin and confocal microscopy, we show that the penetration of the antibiotic peptide bacitracin into the epidermis is enhanced when the skin has been pretreated with liposomes loaded with 30 mol % 6-ketocholestanol, a compound known to increase the magnitude of the membrane dipole potential. Studies using the fluorescent indicators fluoresceinphosphatidylethanolamine and 1-(3-sulfonatopropyl)-4-[beta [2-(di-n-octylamino)-6-naphthyl] vinyl] pyridinium betaine show that the interaction of bacitracin with model membranes is also enhanced by the presence of 6-ketocholestanol in the bilayer and offers some indication to the mechanism of penetration enhancement.

Adjuvants, Pharmaceutic↗
PubMed1980

Bacitracin therapy in antibiotic-associated pseudomembranous colitis.

Two patients with antibiotic-associated pseudomembranous colitis, and stool positive for Clostridium difficile cytotoxin were successfully treated with oral bacitracin. One patient had previously suffered two relapses of pseudomembranous colitis following successful treatment with vancomycin and one patient was allergic to vancomycin. Bacitracin appears to be a reasonable choice to treat patients with antibiotic-associated colitis who are allergic to vancomycin. Further studies comparing vancomycin and bacitracin are needed.

Adult↗
PubMed1985

Enhancement of bacitracin biosynthesis by branched-chain amino acids in a regulatory mutant of Bacillus licheniformis.

DL-4-Azaleucine-resistant mutant of Bacillus licheniformis azlr-1 isolated after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis, was a better bacitracin producer than the parent strain. In the minimal medium, the antibiotic biosynthesis was 4 times higher in the mutant than in the parent strain and less dependent on L-leucine addition. In the complex fermentation medium, the yield was 18-20% higher in the mutant strain. Transaminase B activity measured in the crude extract revealed that the branched-chain amino acid biosynthetic enzymes were 5-10 times derepressed supplying bacitracin synthetase with enhanced quantity of isoleucine and leucine, the building units of bacitracin molecule.

Amino Acids, Branched-Chain↗
PubMed2006

Detection of residual bacitracin A, colistin A, and colistin B in milk and animal tissues by liquid chromatography tandem mass spectrometry.

Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-MS/MS) was applied to the determination of residual bacitracin A, colistin A, and colistin B in milk and animal tissue samples. Prior to instrumental analysis, samples were subjected to acid extraction followed by solid-phase cleanup using Strata-X cartridges. Mass spectral acquisitions were performed under selective multiple reaction monitoring (MRM) mode at m/z 199 and 670 from triply charged precursors of bacitracin A (m/z 475); m/z 385 and 379 from triply charged precursors of colistin A (m/z 391); and m/z 380 and 374 from triply charged precursors of colistin B (m/z 386). Method precision was evaluated from spike recovery of samples fortified at concentrations corresponding to 2/5 of the maximum residue limits (MRLs) for each of the analytes under study. Intra-day and inter-day variations were found to range from 90.9 to 104% with relative standard deviation (RSD) <6.5%, and from 90.1 to 106% with RSD <9.1%, respectively. Limits of quantification (LOQs) were defined as the spiking concentrations at 2/5 MRL, and limits of detection (LODs) were 10-47 microg kg(-1) for bacitracin A, 1-16 microg kg(-1) for colistin A, and 6-14 microg kg(-1) for colistin B in milk and animal tissues. The presented method has good precision and high sensitivity and was applied as a fast screening protocol and a quantitative tool for monitoring of the concerned polypeptides in foods as part of a surveillance program.

Animals↗
PubMed2002

Distribution and variation of bacitracin synthetase gene sequences in laboratory stock strains of Bacillus licheniformis.

Distribution and variation of bacitracin synthetase gene (bac) sequences in 22 laboratory stock strains of Bacillus licheniformis were studied by Southern hybridization of bac gene probes from B. licheniformis ATCC 10716 to genomic PstI or HindIII restriction fragments. Eleven strains gave hybridization signals. These hybridization patterns were classed into two types. Eight strains showed similar patterns to that of ATCC 10716 and all, except one, produced bacitracin. The three strains showed fairly different hybridization patterns from that of ATCC 10716, and one (ATCC 33632) of them produced bacitracin. None of the remaining 11 strains, including ATCC 14580 (type strain), gave any hybridization signals. All strains carrying bac gene sequences were erythromycin resistant. With one exception, all strains without bac gene sequences were erythromycin sensitive. These results show that B. licheniformis strains are divided into two groups with respect to presence of bac gene sequences and erythromycin resistance.

Anti-Bacterial Agents↗
PubMed2004

Dissemination of emm28 erythromycin-, clindamycin- and bacitracin-resistant Streptococcus pyogenes in Spain.

Reported here is an unusual cluster of non-invasive infections caused by an emm28 Streptococcus pyogenes strain resistant to bacitracin, erythromycin and clindamycin detected in Santander, Spain. Since one of the characteristics of group A streptococci is their almost uniform susceptibility to bacitracin, this finding was unusual, and a search for bacitracin-resistant Streptococcus pyogenes strains was conducted in two other distant cities of Spain (Madrid and San Sebastián) where their presence was confirmed. These strains were frequently associated with erythromycin- and clindamycin-resistance, and most of them belonged to a unique emm28 T28, ST52 clone.

Bacitracin↗
PubMed1988

Further evidence for the presence of a thiazoline ring in the isoleucylcysteine dipeptide intermediate in bacitracin biosynthesis.

Isoleucylcysteine dipeptide, a first intermediate peptide in bacitracin biosynthesis, was liberated from the enzyme protein and oxidized with manganese dioxide in dimethylsulfoxide. The resulting oxidation product was identified by thin-layer chromatography as 2-(2-methyl-l-oxobutyl)-thiazole-4-carboxylic acid which has been isolated from the hydrolysate of bacitracin F. This result shows that the intermediate dipeptide contains a thiazoline ring, and that the thiazoline ring is synthesized at the dipeptide stage in the process of peptide chain elongation in bacitracin biosynthesis. Improbability of non-enzymatic dehydrative cyclization of the dipeptide is discussed.

Bacitracin↗
PubMed1992

Preparative high-performance liquid chromatographic separation and isolation of bacitracin components and their relationship to microbiological activity.

Bacitracin, a polypeptide antibiotic, is one of the most commonly used antibiotics in the world. The approved method of analysis for bacitracin is microbial. To correlate the microbiological method with a high-performance liquid chromatographic (HPLC) method, bacitracin was chromatographed using HPLC with ultraviolet detection and a YMC basic column. Adequate separation of the isomers was obtained to scale up this procedure to preparative HPLC using a Prep HPLC system and a 250 x 21 mm YMC basic column. The various fractions were separated, isolated and examined for microbial activity. The individual fractions could be precipitated by adding zinc or methylene disalicylic acid and lowering the pH. The crude fractions were recycled to ensure chromatographic purity. The chromatograms can accurately predict (in minutes) the microbiologically determined potency which usually takes 16-24 h to develop. The chromatographic procedure also provides information on the amounts of isomers and degradation products present in the sample, whereas the microbiological assay only provides activities or potencies of the antibiotic. The reported HPLC method also possesses some advantages over some other published HPLC methods in terms of accuracy and time of analysis.

Anti-Bacterial Agents↗