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The bacA gene, which determines bacitracin susceptibility in Streptococcus pneumoniae and Staphylococcus aureus, is also required for virulence.

Homologues of Escherichia coli bacA, encoding extremely hydrophobic proteins, were identified in the genomes of Staphylococcus aureus and Streptococcus pneumoniae. Allelic replacement mutagenesis demonstrated that the gene is not essential for in vitro growth in either organism, and the mutants showed no significant changes in growth rate or morphology. The Staph. aureus bacA mutant showed slightly reduced virulence in a mouse model of infection and an eightfold increase in bacitracin susceptibility. However, a Strep. pneumoniae bacA mutant was highly attenuated in a mouse model of infection, and demonstrated an increase in susceptibility to bacitracin of up to 160000-fold. These observations are consistent with the previously proposed role of BacA protein as undecaprenol kinase.

Amino Acid Sequence↗

Bacillus licheniformis bacitracin-resistance ABC transporter: relationship to mammalian multidrug resistance.

The nucleotide sequence of the Bacillus licheniformis bacitracin-resistance locus was determined. The presence of three open reading frames, bcrA, bcrB and bcrC, was revealed. The BcrA protein shares a high degree of homology with the hydrophilic ATP-binding components of the ABC family of transport proteins. The bcrB and bcrC genes were found to encode hydrophobic proteins, which may function as membrane components of the permease. Apart from Bacillus subtilis, these genes also confer resistance upon the Gram-negative Escherichia coli. The presumed function of the Bcr transporter is to remove the bacitracin molecule from its membrane target. In addition to the homology of the nucleotide-binding sites, BcrA protein and mammalian multidrug transporter or P-glycoprotein share collateral detergent sensitivity of resistant cells and possibly the mode of Bcr transport activity within the membrane. The advantage of the resistance phenotype of the Bcr transporter was used to construct deletions within the nucleotide-binding protein to determine the importance of various regions in transport.

ATP-Binding Cassette Transporters↗

Reevaluation of bacitracin as a spore coat component.

Analysis of hydrolysates of highly purified spore coats revealed only small quantities of ornithine, a component of bacitracin. We conclude that the peptide, bacitracin, is not a significant component of spore coats.

Amino Acids↗

Differentiation of Staphylococcus and Micrococcus spp. with the Taxo A bacitracin disk.

Taxo A bacitracin disks (BBL Microbiology Systems, Cockeysville, Md.) were evaluated as a test for differentiating staphylococci from micrococci in clinical laboratories. All staphylococci tested were resistant to the disks, with no zone of growth inhibition. Zones of growth inhibition ranging from 10.5 to 25.0 mm in diameter were observed with all micrococci except two isolates which failed to grow on the test medium. These findings were confirmed by minimal inhibitory concentrations to bacitracin. Staphylococci had minimal inhibitory concentrations significantly higher than those of micrococci, with no overlap in the ranges of values.

Bacitracin↗

Further studies on the reliability of the bacitracin inhibition test for the presumptive identification of Lancefield group A streptococci.

The reliability of the bacitracin inhibition test to differentiate between 125 Lancefield group A and 122 non-group A beta-haemolytic streptococci was studied. Bacitracin discs containing 0-02, 0-04, or 0-1 international units and the conditions recommended by both the Association of Clinical Pathologists and the Federal Drug Administration for routine sensitivity testing were used. The results suggest that the presence or absence of a zone of inhibition around a 0-04 unit disc can be used routinely for the presumptive identification of group A streptococci and that a specific zone size can be used for reading the test only with a 0-1 unit disc.

Bacitracin↗

Neomycin and the combination of neomycin and bacitracin in the prevention of bacterial infection in surgery of the colon and/or rectum.

In two groups of patients submitted to surgery of the colon and/or rectum, treatment to prevent bacterial infections using a combination of 100 mg neomycin and 10,000 U bacitracin every 6 h for 48 h gave the same results as neomycin employed alone at a dosage of 500 mg every 6 h for 48 h. Results confirm the synergism of action between neomycin and bacitracin.

Adult↗

Effects of additives on in vitro ruminal fermentation: a comparison of monensin and bacitracin, another gram-positive antibiotic.

Mixed ruminal bacteria (n = 4) were incubated in anaerobic media for 24 h in vitro with either hay, corn meal, protein hydrolyzate or hydrogen gas as the substrate. The ionophore monensin and the polypeptide antibiotic bacitracin were added to the incubation flasks at concentrations ranging from 0 to 10 or 40 mg/liter. As was expected, monensin decreased methane production, increased the ratio of propionate to acetate and decreased the deamination of amino acids. Monensin had little effect on methane production, however, if hydrogen gas was the fermentation substrate. Bacitracin, another gram-positive antibiotic with a distinctly different cellular target, was somewhat less potent than monensin, but it produced strikingly similar responses. This similarity of fermentation patterns suggested that monensin action in the rumen is probably due to its activity as a gram-positive antibiotic, and that any gram-positive antibiotic not suppressed by resistance may produce fermentation effects similar to those of monensin. The cellular action of monensin as an ionophore in membranes is probably little more than a means of inhibiting sensitive species. Many gram-positive antibiotics have little affect on ciliate protozoa or coccidia.

Animals↗

Response of broiler chickens to dietary supplementation with roxarsone and bacitracin methylene disalicylate in diets containing narasin.

Six trials were conducted at different locations to examine the response of broiler chickens to roxarsone and bacitracin in the form of bacitracin methylene disalicylate (BMD) in the presence of the anticoccidal narasin. All diets contained narasin (80 mg/kg) and were fortified with a factorial arrangement of roxarsone (0 to 50 mg/kg) and BMD (0 or 55 mg/kg). Broilers were grown to market weights with narasin and roxarsone removed from the diets for the final 5 days. Addition of both roxarsone and BMD resulted in significant (P less than .05) improvements in body weight and feed utilization. Response to roxarsone for feed utilization was influenced to some extent by the presence or absence of BMD. Although the response to roxarsone was always positive, the degree of response was lessened by the presence of BMD. This resulted in a significant (P less than .10) interaction between roxarsone and BMD for feed utilization but not for body weight.

Animal Feed↗

Response of guinea fowl (Numida meleagris) to dietary supplementation of zinc bacitracin.

The effect of dietary bacitracin on the growth and feed conversion of guineas has been investigated using graded levels of the antibiotic. The treatments were 0, 11, 22, and 45 mg bacitracin/kg diet. Poorest live weights were recorded by unmedicated guineas. Keets given bacitracin at 11 mg/kg recorded significantly higher live weights (P less than .05) than unmedicated chicks. Best live weights were obtained at a supplementation level of 22 mg/kg; supplementation to 45 mg/kg gave no further growth improvement.

Animal Feed↗

Effect of roxarsone and bacitracin methylene disalicylate on the development of immunity to Eimeria in broilers given a live coccidiosis vaccine.

No significant differences in the BW, feed intake, feed conversion, or mortality of broilers that had been vaccinated at 3 d of age with a live coccidiosis vaccine were observed irrespective of whether they had been given roxarsone, bacitracin methylene disalicylate, or both drugs in the feed. The weight gain of birds challenged with a high dose of the vaccine at 51 d was not significantly different from that of unchallenged birds and no lesions of Eimeria species were found in their intestines irrespective of the medication given. It is concluded that roxarsone and bacitracin methylene disalicylate do not interfere with the acquisition of immunity to Eimeria species in broilers.

Animals↗

Total structures and antimicrobial activity of bacitracin minor components.

Total structures of 13 minor components of bacitracin (BC) were proposed, and their antimicrobial activities were investigated. The components of BC including bacitracins A (BC-A) and F (BC-F) were isolated by preparative HPLC and were hydrolyzed under acidic conditions. The resulting amino aids were derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-alanineamide and were separated by HPLC to determine their absolute configurations. It was found that the N-terminal amino acids of BC-A and its related components were epimerized during the hydrolysis to yield their enantiomers. The formation of these artifactual amino acids suggests that our previously proposed structures of the BC minor components are incorrect; therefore, the structures were corrected based on these results. The structures of the BC minor components were the same as that of BCs-A and -F except that one to three of the L-isoleucines, including the N-terminal one, were replaced by L-valines. These structures were confirmed by tandem mass spectrometry under fast atom bombardment (FAB) conditions and Frit-FAB liquid chromatography/mass spectrometry. Based on the UV spectra of the BC components determined by photodiode array detection-HPLC analysis, a new systematic nonmenclature was proposed for the minor components. The isolated components were also used for the determination of their minimal inhibition concentrations and it was found that BC-A is 2 approximately 8 times more potent than the other minor components against strains of Micrococcus luteus and Staphylococcus aureus.

Amino Acid Sequence↗

Use of bacitracin in the prevention and treatment of experimentally-induced idiopathic colitis in horses.

Ten healthy ponies from a single herd were found by repeated fecal culture to be free of Salmonella species and Clostridium cadaveris. In a preliminary study, four ponies administered a single oral dose of 10 mg/kg lincomycin did not develop idiopathic colitis when the drug was administered alone. Four other ponies were administered 10 mg/kg lincomycin by stomach tube together with 0.45 L of colonic content from a horse with idiopathic colitis induced earlier by lincomycin alone. Two of the four ponies were treated with 25 g oral zinc bacitracin premix (110 g/kg active ingredient) 24 h later. Forty-two hours after inoculation the two untreated ponies had severe signs of idiopathic colitis and were euthanized. Postmortem findings were typical of idiopathic colitis. The two treated ponies had milder illness but the more severely affected was also euthanized; the other was retreated at 42 h with bacitracin pre-mix and again 12 h later. Its illness and diarrhea resolved over the next 24 h. Clostridium cadaveris was isolated in large numbers from the cecum of the euthanized ponies and their cecal content contained mouse lethal and guinea pig dermonecrotic, but not cytotoxic, activity. Enterotoxins of Clostridium perfringens and Clostridium difficile could not be demonstrated. No toxin could be demonstrated in culture supernatants of C. cadaveris or in supernatants of cecal contents treated with ethanol prior to culturing in anaerobically incubated broth. No Salmonella spp. were isolated. A further two ponies were administered 10 mg/kg lincomycin orally with 0.45 L colonic content from a horse with idiopathic colitis, as described.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Bacitracin.

Bacitracin is an antibiotic widely used by both the medical profession and the general public. It is most commonly found in a variety of topical ointments and creams used after surgical procedures, for acute skin injuries, and for chronic wounds. The incidence of allergy to this agent has been increasing over the last 10 years, probably because of more frequent use. This article reviews basic information about bacitracin as an allergen, including sources of exposure, chemical composition, types of allergic reactions, and patch testing.

Administration, Topical↗

[Bacitracin and gramicidin S as biospecific ligands for affinity chromatography of human thrombin].

It was shown that the cyclic polypeptide antibiotic bacitracin is a competitive inhibitor of fibrinogen clotting by thrombin. Biospecific adsorbents for isolation of thrombin by gramicidin S and bacitracin attachment to silochrome S-80 modified by gamma-glycido-oxypropyl groups were synthesized. The thrombin yield at pH 7.2 and 8.0 was 76.5-96%, purification--6.2-11.6-fold, specific coagulating activity--940-1750 NIH u./mg protein. At pH 6.1 the enzyme does not practically bind to the adsorbents. In all probability, the differences in thrombin binding are due to conformational changes in the enzyme molecule, when pH changes from 6.1 to 7.2. Possible application of the synthesized adsorbents for obtaining laboratory and commercial preparations of thrombin and their perspective use for purification of other blood plasma serine proteinases possessing a narrow specificity are discussed.

Bacitracin↗

[In vitro antibacterial activity of neomycin, bacitracin and a combination of both].

Bacitracin and neomycin have been used for a long time for local intestinal antisepsis or decontamination, due to their scarce or nonexistent intestinal absorption. The aim of the present study was to determine the activity of bacitracin and neomycin against recent clinical isolates of aerobic and anaerobic microorganisms and to verify their capacity to have a synergistic effect and to prevent the emergence of bacterial resistance when in combination. The results showed that the activity of either antibiotic against recent clinical isolates (even if resistant to cephalosporins and aminoglycosides) is similar to that originally displayed at the time introduction in therapy. Generally the combination of the two antibiotics showed a synergistic or additive effect and prevented the selection of resistant strains.

Bacitracin↗

The use of bacitracin irrigation to prevent infection in postoperative skeletal wounds. An experimental study.

In dogs, irrigation of contaminated osseous wounds with bacitracin eliminated clinical evidence of infection and significantly reduced the number of positive cultures and pathological evidence of infection when compared with dogs that received no treatment or irrigation with normal saline solution. The inocula contained more organisms than are introduced into a wound during an elective orthopaedic operation. The use of bacitracin in the prevention of postoperative Staphylococcus aureus infection of bone in humans may be justified.

Animals↗

[Interaction of the peptide antibiotic bacitracin with DNA and synthetic polynucleotides].

The aim of the present paper was to study the specific character of interaction of peptide antibiotic bacitracin with DNA and to estimate the interaction constant. The influence of bacitracin on bacteriophage DNA restriction by HindIII and SmaI endonucleases was studied. The possibility of arranging the polynucleotide template by small ligands was shown.

Bacitracin↗