Resistance bacitracin

Interestingly, the selection of variants with reduced branching rates and enhanced strength of the cell wall results in a significantly enhanced production of erythromycin. This led Wardell et al. to search for the correlation between resistances to cell wall inhibitors bacitracin, tunicamycin and penicillin and production of the antibiotic. Significantly greater erythromycin titers were observed in the cultures of the tunicamycin- and penicillin-resistant mutants, whereas bacitracin-resistant mutant produced less antibiotic than the original strain. 

Staphylococcus aureus - [ANTIBIOTICS - BETA-LACTAMS - CEPHALOSPORINS] (Vol 3) - [DISINFECTANTS AND ANTISEPTICS] (Vol 8) - [ANTIBIOTICS - BETA-LACTAMS - BETA-LACTAMASE INHIBITORS] (Vol 3) - [ANTIBIOTICS - LINCOSAMINIDES] (Vol3) - [ANTIBIOTICS - BETA-LACTAMS - PENICILLINS AND OTHERS] (Vol 3) - [ANTIBIOTICS-AMINOGLYCOSIDES] (Vol2) - [ANTIBIOTICS - GLYCOPEPTIDES(DALBAHEPTIDES)] (Vol 2) -bacitracin resistance [ANTIBIOTICS - PEPTIDES] (Vol 3) -ethanol activity against [DISINFECTANTS AND ANTISEPTICS] (Vol 8) -inhibited by sorbates [SORBIC ACID] (Vol 22)... 

Matos R, Pinto VV, Ruivo M, Lopes MED, Study on the dissemination of the bcrABDR cluster in Enterococcus spp reveals that the BCRAB transporter is sufficient to confer high level bacitracin resistance, Int. J. Antimicrob. Agents 2009 34 142-147. 

Comparison of the two mutant strains of B. megaterium, resistant to bacitracin and Su 2079, respectively, revealed that the 1735 cm" band was present in both cases, while the 1176 cm" band seen in the strain resistant to the thiourea compound was absent in the curve produced by the cells resistant to bacitracin. The strain resistant to the Su 2079 had a spectrum without a band at 835 cm". The 835 cm" band was distinct in the spectrum of the bacitracin-resistant cells. Thus, infrared spectroscopy differentiated between sensitive and resistant strains. 

Acquired resistance to bacitracin has been observed in laboratory strains of Staph, aureus, but resistance has been unstable and no resistant mutants have yet been isolated in vivo. Gram-negative bacteria are intrinsically resistant to bacitracin, which inhibits the transfer of pentapeptide units to petidoglycan. 

C. Teicoplanin, although used in Europe, is not approved for use in the United States. It can be used to treat a variety of gram-positive infections and should be considered in resistant gram-positive infections as well. Bacitracin and polymyxins are topical agents with potential for serious nephrotoxicity when used parenterally. Linezolid is recently approved for resistant gram-positive infections (VRE and MRSA) and is available in the United States. 

The use of bacitracin in the anterior nares may temporarily decrease colonization by pathogenic staphylococci. Microbial resistance may develop following prolonged use. Bacitracin-induced contact urticaria syndrome, including anaphylaxis, occurs rarely. Allergic contact dermatitis occurs frequently, and immunologic contact urticaria rarely. Bacitracin is poorly absorbed through the skin, so systemic toxicity is rare. 

Bacitracin is seldom used parenterally because renal necrosis has been reported after systemic use. Bacitracin is primarily used topically to treat skin and mucous membrane infections caused by gram-positive bacteria because only a few of these bacteria have become resistant to it. 

Polymyxin B is bactericidal fc>r most gram-negative organisms, especially Haemophilus and Pseudomonas species. Neisseria and Proteus species, however, are resistant. Combining polymyxin B with bacitracin or trimethoprim achieves broad-spectrum antibacterial activity for treating acute bacterial conjunctivitis. Because it is not absorbed through mucous membrane or skin tissue, polymyxin B is used primarily for superficial infections.Adverse reactions are rare. 

Antibiotic therapy should be limited to periods of disease exacerbation, with the eyelid hygiene providing the daily maintenance regimen. Occasionally, topical erythromycin, bacitracin, or bacitracin-polymyxin B ointment applied at bedtime for several weeks proves beneficial as part of the therapeutic protocol. This type of chronic therapy, however, always carries the risk of fitster-ing overgrowth of resistant organisms. 

Although there is evidence of acquired resistance to bacitracin in enterococci and staphylococci isolated from animals (11), a review found no evidence that the prevalence of such resistance has increased over time or in relation to the use of bacitracin in man or in animals (in which bacitracin is used as a growth promoter) (12). 

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