Administration Of Bacitracin Research Articles

Real-Time Quantitative PCR Measurement of Ileal Lactobacillus salivarius Populations from Broiler Chickens To Determine the Influence of Farming Practices

A real-time quantitative PCR assay targeting a 16S-23S intergenic spacer region sequence was devised to measure the sizes of populations of Lactobacillus salivarius present in ileal digesta collected from broiler chickens. This species has been associated with deconjugation of bile salts in the small bowel and reduced broiler productivity. The assay was tested as a means of monitoring the sizes of L. salivarius populations from broilers fed diets with different compositions, maintained at different stocking densities, or given the antimicrobial drugs bacitracin and monensin in the feed. Stocking densities did not influence the numbers of L. salivarius cells in the ileum. A diet containing meat and bone meal reduced the size of the L. salivarius population relative to that of chickens given the control diet, as did administration of bacitracin and monensin in the feed. These changes in the target bacterial population were associated with improved broiler weight gain.

Relationship of Dietary Antimicrobial Drug Administration with Broiler Performance, Decreased Population Levels of Lactobacillus salivarius, and Reduced Bile Salt Deconjugation in the Ileum of Broiler Chickens

Straight-run broiler chickens were raised either in floor pens or wire-floored cages (trial 1) or in floor pens only (trials 2, 3, and 4). Birds raised in floor pens had lower BW and feed intakes than those raised in cages. The administration of bacitracin in the feed increased feed intake from d 12 to d 35, decreased the feed conversion ratio during the same period in trial 2, and improved the weight gain of broilers from d 0 to 10 in trial 3. The concentrations of conjugated bile salts (taurocholic and taurochenodeoxycholic acids) were higher in the ileal contents of broilers administered the antimicrobials compared with untreated birds. Supplementation of the feed with monensin increased fat digestibility in the ileum of the birds. Although total numbers of bacteria in ileal contents were the same regardless of whether antimicrobials were administered or not, the bacterial community differed qualitatively. Populations of Lactobacillus salivarius were reduced in birds fed antimicrobials relative to untreated broilers. A representative ileal isolate of L. salivarius deconjugated bile salts in pure culture in the laboratory and in the ileal contents of ex-Lactobacillus-free chickens maintained in a protective environment and colonized by the Lactobacillus isolate. These observations provide a link between bile salt deconjugation in the ileum by L. salivarius and decreased weight gain of broilers. Lactobacillus salivarius populations could be targeted in future studies aimed at modification of the ileal bacterial community to achieve growth promotion of broilers without the administration of antimicrobial drugs.

The effect of inhibitors of endogenous opioid degradation, bacitracin, bestatin, captopril, and D-phenylalanine, on digoxin-induced arrhythmias in guinea pigs.

The purpose of this study was to investigate the effect of inhibition of endogenous opioid degradation on digitalis-induced arrhythmias, utilizing the inhibitors bacitracin, bestatin, captopril, and D-phenylalanine. Guinea pigs, anesthetized with pentobarbital, 50 mg/kg i.p., and breathing spontaneously received intracerebroventricular (i.c.v.) injection of bacitracin (6.8 mg/kg), bestatin (1 mg/kg), captopril (2 mg/kg), D-phenylalanine (1.2 mg/kg) or the diluent, saline. Digitalis arrhythmias were induced by a 50 micrograms/kg i.v. bolus of digoxin followed by 500 micrograms.kg-1.h-1 i.v. Bacitracin and bestatin, but not captopril or D-phenylalanine, significantly (p less than 0.05) altered the relationship between the digoxin dose and the first occurrence of arrhythmias, i.e., digoxin-induced ventricular arrhythmias became manifest at lower digoxin doses. The mean digoxin dose and ED50s, at which arrhythmias first occurred, were significantly (p less than 0.05) reduced by bacitracin and bestatin. The findings were similar for fatal arrhythmias, although D-phenylalanine appeared to decrease the digoxin dose at the development of fatal arrhythmias. The opioid antagonist naloxone, in a 50 micrograms/kg bolus and 50 micrograms.kg-1.h-1 i.c.v., completely prevented these effects of bacitracin and reduced the effect of bestatin. The relationship to arrhythmias could not be ascribed to an effect on blood pressure, as the blood pressure response to digoxin was the same in bestatin, D-phenylalanine, and control groups. To examine whether systemic administration of an inhibitor of opioid degradation had similar effects, a second protocol was selected with systemic administration of bacitracin because it altered the dose effect relationship after i.c.v. administration and systemic concentrations could be readily attained. Bacitracin, in a 13.5 mg/kg i.v. bolus and 135 mg.kg-1.h-1 i.v., was followed by 100 micrograms/kg digoxin i.v. every 15 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of antibiotics on intestinal mucin in healthy subjects.

To determine the effect on microbial breakdown of intestinal mucin healthy volunteers were treated orally with ten different antibiotics. The most pronounced effects were seen after administration of bacitracin, clindamycin or vancomycin: the electrophoretic mucin pattern in faeces changed from a normal conventional pattern to a specific pattern similar to that found in germ-free rats. Disturbed patterns were also observed in some of the subjects treated with ampicillin, doxycycline, erythromycin, metronidazole or nalidixic acid. In most cases the electrophoretic mucin pattern normalized within five weeks after the end of treatment. There were no effects on the microbial breakdown of intestinal mucin in the groups treated with ofloxacin or trimethoprim/sulfamethoxazole. Thus, administration of antimicrobial drugs in clinically recommended doses may cause long-term disturbances in one microflora-associated characteristic, the breakdown of intestinal mucin.

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.