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Bulletin of the World Health... 1953In 1952, the Department of Biological Standards, National Institute for Medical Research, London, was authorized by the WHO Expert Committee on Biological...
In 1952, the Department of Biological Standards, National Institute for Medical Research, London, was authorized by the WHO Expert Committee on Biological Standardization to proceed with the establishment of an International Standard for Bacitracin. Thirty grams of bacitracin were obtained and it was decided to compare the proposed International Standard with the existing Working Standard for Bacitracin of the United States Food and Drug Administration.Six laboratories in five countries participated in the collaborative assay. A total of 52 assays was carried out, but the overall weighted mean potency was calculated from only the 48 biological assays, the 4 assays by the Hiscox method being excluded. The biological assays were done by the plate, the cylinder, or the disc method, using Streptococcus pyogenes, Staphylococcus aureus, Corynebacterium xerosis, or Micrococcus flavus.After analysing the results by standard statistical methods, the authors established the batch of bacitracin examined as the International Standard. The Standard contains 55 International Units of activity per mg, and the International Unit has therefore been defined as the activity contained in 0.0182 mg of the International Standard for Bacitracin.
Topics: Bacitracin; Biological Assay; Humans; Laboratories; Reference Standards; Staphylococcus aureus; United States
PubMed: 13141138
DOI: No ID Found -
Poultry Science May 2024The poultry industry is evolving towards antibiotic-free production to meet market demands and decelerate the increasing spread of the antimicrobial resistance. The...
The poultry industry is evolving towards antibiotic-free production to meet market demands and decelerate the increasing spread of the antimicrobial resistance. The growing need for antibiotic free products has challenged producers to decrease or completely stop using antimicrobials as feed supplements in broiler diet to improve feed efficiency, growth rate, and intestinal health. Natural feed additives (e.g., probiotics and phytobiotics) are promising alternatives to substitute antimicrobial growth promoters. The goal of our study was to characterize the effects of a Probiotic and an Essential Oils blend on broilers' performance and perform a time-series analysis to describe their excreta microbiome. A total of 320 Cobb 500 (1-day-old) chicks were raised for 21 d in 32 randomly allocated cages. Treatments consisted of 4 experimental diets: a basal diet, and a basal diet mixed with an Antibiotic (bacitracin methylene disalicylate), an essential oils blend (oregano oil, rosemary, and red pepper), or a Probiotic (Bacillus subtilis). Body weight (on 1, 10, and 21d), and feed intake (10d and 21d) were recorded and feed conversion ratio was calculated. Droppings were collected daily (1-21d) to characterize broilers' excreta microbiota by targeted sequencing of the bacterial 16S rRNA gene. The Probiotic significantly improved feed conversion ratio for starter phase 1 to 10d (P = 0.03), grower phase 10 to 21d (P = 0.05), and total period 1 to 21d (P = 0.01) compared to the Antibiotic. Feed supplements did not affect alpha diversity but did impact microbial beta diversity (P < 0.01). Age also impacted microbiome turnover as differences in alpha and beta diversity were detected. Furthermore, when compared to the basal diet, the probiotic and antibiotic significantly impacted relative abundance of Bifidobacterium (log2 fold change -1.44, P = 0.03), Intestinimonas (log2 fold change 0.560, P < 0.01) and Ligilactobacillus (log2 fold change -1.600, P < 0.01). Overall, Probiotic supplementation but not essential oils supplementation positively impacted broilers' growth performance by directly causing directional shifts in broilers' excreta microbiota structure.
Topics: Animals; Chickens; Animal Feed; Probiotics; Diet; Dietary Supplements; Oils, Volatile; Anti-Bacterial Agents; Feces; Gastrointestinal Microbiome; Bacitracin; Random Allocation; Bacillus subtilis; Microbiota; Male; Plant Oils; Salicylates
PubMed: 38484563
DOI: 10.1016/j.psj.2024.103604 -
Environment International Jan 2020Antimicrobial peptides (AMPs) are increasingly important as a last resort against multi-drug resistant bacteria due to resistance formation towards conventional...
Antimicrobial peptides (AMPs) are increasingly important as a last resort against multi-drug resistant bacteria due to resistance formation towards conventional antibiotics. However, many AMPs were introduced to the market before environmental risk assessment was required, e.g., by the European Medicines Agency (EMA) since 1998. While AMPs have been administered as antibiotics and growth promotors in feedstock since the 1960s and were reconsidered for human medicine by the EMA in 2013, details about their mobility and persistence in the environment remain unknown. This study investigated the environmental fate of three commonly used AMPs: bacitracins, daptomycin, and polymyxins B and E (Colistin). We observed moderate sorption affinity of daptomycin to standard European soils (K = 20.6-48.6), while polymyxins adsorbed irreversibly. Bacitracin variants sorbed slightly to sandy soil (K = 5.8-8) and significantly to clayey soil (K = 169-250). We further investigated photochemical and microbial transformation processes relevant in surface waters. We demonstrated that phototransformation of all AMPs was enhanced in the presence of dissolved organic matter and fast bimolecular reaction rate constant with singlet oxygen contributed largely to indirect phototransformation (15-41%). Phototransformation product analysis for daptomycin was consistent with expected modifications of the tryptophan and kynurenine moieties. Moreover, riverine biofilm communities demonstrated biotransformation potential for all AMPs. Our findings of sorption behaviour, photo- and biotransformation suggest that these processes play a critical role in the fate of bacitracins, daptomycin, and polymyxins in environmental systems.
Topics: Anti-Bacterial Agents; Bacitracin; Colistin; Daptomycin; Humans; Polymyxins
PubMed: 31704562
DOI: 10.1016/j.envint.2019.105271 -
Frontiers in Cellular and Infection... 2022, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of is involved in collagen binding, but its other biological...
, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability.
Topics: ATP-Binding Cassette Transporters; Adhesins, Bacterial; Anti-Bacterial Agents; Bacitracin; Base Composition; Biofilms; Carrier Proteins; Chloramphenicol; Collagen; Glucans; Membrane Proteins; Permeability; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Streptococcus mutans
PubMed: 36176579
DOI: 10.3389/fcimb.2022.994014 -
Journal of Applied Microbiology May 2008Determining the effects of zinc bacitracin, bird age and access to range on bacterial microbiota in the ileum and caeca of broilers.
AIMS
Determining the effects of zinc bacitracin, bird age and access to range on bacterial microbiota in the ileum and caeca of broilers.
METHODS AND RESULTS
16S rRNA gene-based polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) profiling, DNA sequencing and real-time quantitative PCR techniques were used. The richness of both ileal and caecal microbiota increased with chicken age. The microbiota from those birds of the same age demonstrated relatively similar PCR-DGGE profiles and tended to form closely related clusters in the relatedness analyses. Dietary treatment with bacitracin (50 mg kg(-1)) and access to range did not change the richness but altered the composition of the microbiota. The impact of bacitracin was particularly obvious in 3-day-old chicks. Lactobacilli were abundant in the caecal microbiota of 3-day-old chicks regardless of the dietary treatment with bacitracin. The access to range enriched Bifidobacterium in both the ileum and caeca.
CONCLUSIONS
Bacitracin, bird age and access to range all influenced bacterial microbiota in the ileum and caeca of broilers, with bird age having the greatest apparent effect.
SIGNIFICANCE AND IMPACT OF THE STUDY
Providing useful information for the development of antibiotic replacement therapy for poultry production.
Topics: Aging; Animal Feed; Animal Husbandry; Animals; Anti-Bacterial Agents; Bacitracin; Bacteria; Bifidobacterium; Cecum; Chickens; DNA, Bacterial; Gastrointestinal Contents; Ileum; Polymerase Chain Reaction; RNA, Ribosomal, 16S
PubMed: 18201175
DOI: 10.1111/j.1365-2672.2007.03699.x -
Microbiology (Reading, England) Sep 2015Streptococcus mutans in dental biofilms often faces life-threatening threats such as killing by antimicrobial molecules from competing species or from the host. The...
Identification and characterization of SMU.244 encoding a putative undecaprenyl pyrophosphate phosphatase protein required for cell wall biosynthesis and bacitracin resistance in Streptococcus mutans.
Streptococcus mutans in dental biofilms often faces life-threatening threats such as killing by antimicrobial molecules from competing species or from the host. The ability of S. mutans to cope with such threats is crucial for its survival and persistence in dental biofilms. By screening a transposon mutant library, we identified 11 transposon insertion mutants that were sensitive to bacitracin. Two of these mutants, XTn-01 and XTn-03, had an independent insertion in the same locus, SMU.244, which encoded a homologue of undecaprenyl pyrophosphate phosphatase (UppP). In this study, we describe the genetic and phenotypic characterization of SMU.244 in antibiotic resistance. The results revealed that deletion of SMU.244 results in a mutant (XTΔ244) that is highly sensitive to bacitracin, but confers more resistance to lactococcin G, a class IIb bacteriocin. Introduction of the intact SMU.244 into XTΔ244 in trans completely restores its resistance to bacitracin and the susceptibility to lactococcin G. The XTΔ244 was also defective in forming the WT biofilm, although its growth was not significantly affected. Using recombinant protein technology, we demonstrated that the SMU.244-encoded protein displays enzyme activity to catalyse dephosphorylation of the substrate. The lux transcriptional reporter assays showed that S. mutans maintains a moderate level of expression of SMU.244 in the absence of bacitracin, but bacitracin at sub-MICs can further induce its expression. We concluded that SMU.244 encodes an UppP protein that plays important roles in cell wall biosynthesis and bacitracin resistance in S. mutans. The results described here may further our understanding of the molecular mechanisms by which S. mutans copes with antibiotics such as bacitracin.
Topics: Amino Acid Sequence; Anti-Bacterial Agents; Bacitracin; Biofilms; Cell Wall; DNA Transposable Elements; Drug Resistance, Bacterial; Gene Order; Genetic Loci; Microbial Sensitivity Tests; Molecular Sequence Data; Mutagenesis, Insertional; Promoter Regions, Genetic; Pyrophosphatases; Sequence Alignment; Sequence Deletion; Streptococcus mutans; Transcription, Genetic
PubMed: 26198853
DOI: 10.1099/mic.0.000142 -
CMAJ : Canadian Medical Association... Jan 2018
Topics: Bacitracin; Dermatitis, Allergic Contact; Humans; Lidocaine; Polymyxin B
PubMed: 29358205
DOI: 10.1503/cmaj.733515 -
Molecular Microbiology May 2016Protection against antimicrobial peptides (AMPs) often involves the parallel production of multiple, well-characterized resistance determinants. So far, little is known...
Protection against antimicrobial peptides (AMPs) often involves the parallel production of multiple, well-characterized resistance determinants. So far, little is known about how these resistance modules interact and how they jointly protect the cell. Here, we studied the interdependence between different layers of the envelope stress response of Bacillus subtilis when challenged with the lipid II cycle-inhibiting AMP bacitracin. The underlying regulatory network orchestrates the production of the ABC transporter BceAB, the UPP phosphatase BcrC and the phage-shock proteins LiaIH. Our systems-level analysis reveals a clear hierarchy, allowing us to discriminate between primary (BceAB) and secondary (BcrC and LiaIH) layers of bacitracin resistance. Deleting the primary layer provokes an enhanced induction of the secondary layer to partially compensate for this loss. This study reveals a direct role of LiaIH in bacitracin resistance, provides novel insights into the feedback regulation of the Lia system, and demonstrates a pivotal role of BcrC in maintaining cell wall homeostasis. The compensatory regulation within the bacitracin network can also explain how gene expression noise propagates between resistance layers. We suggest that this active redundancy in the bacitracin resistance network of B. subtilis is a general principle to be found in many bacterial antibiotic resistance networks.
Topics: Anti-Bacterial Agents; Bacillus subtilis; Bacitracin; Bacterial Proteins; Cell Wall; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Signal Transduction
PubMed: 26815905
DOI: 10.1111/mmi.13336 -
Journal of Bacteriology Mar 1948
Topics: Bacitracin; Bacteria; Bacteriocins; Humans; In Vitro Techniques; Spirochaeta; Treponema pallidum
PubMed: 16561465
DOI: 10.1128/jb.55.3.347-358.1948 -
Applied and Environmental Microbiology Aug 2020Antibiotics are used to treat or prevent some types of bacterial infection. The inappropriate use of antibiotics unnecessarily promotes antibiotic resistance and...
Potential Risk of Spreading Resistance Genes within Extracellular-DNA-Dependent Biofilms of Streptococcus mutans in Response to Cell Envelope Stress Induced by Sub-MICs of Bacitracin.
Antibiotics are used to treat or prevent some types of bacterial infection. The inappropriate use of antibiotics unnecessarily promotes antibiotic resistance and increases resistant bacteria, and controlling these bacteria is difficult. While the emergence of drug-resistant bacteria is a serious problem, the behavior of drug-resistant bacteria is not fully understood. In this study, we investigated the behavior of , a major etiological agent of dental caries that is resistant to bacitracin, which is a cell wall-targeting antibiotic, and focused on biofilm formation in the presence of bacitracin. UA159 most strongly induced extracellular DNA (eDNA)-dependent biofilm formation in the presence of bacitracin at 1/8× MIC. The Δ and Δ mutant strains, which lack bacitracin resistance, also formed biofilms in the presence of bacitracin at 1/2× MIC. This difference between the wild type and the mutants was caused by the induction of expression in the mid-log phase. We also revealed that certain genes involved in the synthesis of rhamnose-glucose polysaccharide related to cell wall synthesis were downregulated by bacitracin. In addition, glucosyltransferase-I was also involved in eDNA-dependent biofilm formation. The biofilm led to increased transformation efficiencies and promoted horizontal gene transfer. Biofilms were also induced by ampicillin and vancomycin, antibiotics targeting cell wall synthesis, suggesting that cell envelope stress triggers biofilm formation. Therefore, the expression of the and genes is regulated by , which forms eDNA-dependent biofilms, promoting horizontal gene transfer in response to cell envelope stress induced by sub-MICs of antibiotics. Antibiotics have been reported to induce biofilm formation in many bacteria at subinhibitory concentrations. Accordingly, it is conceivable that the MIC against drug-sensitive bacteria may promote biofilm formation of resistant bacteria. Since drug-resistant bacteria have spread, it is important to understand the behavior of resistant bacteria. is bacitracin resistant, and the 1/8× MIC of bacitracin, which is a cell wall-targeted antibiotic, induced eDNA-dependent biofilm formation. The Δ and Δ strains, which are not resistant to bacitracin, also formed biofilms in the presence of bacitracin at 1/2× MIC, and biofilms of both the wild type and mutants promoted horizontal gene transfer. Another cell wall-targeted antibiotic, vancomycin, showed effects on biofilms and gene transfer similar to those of bacitracin. Thus, treatment with cell wall-targeted antibiotics may promote the spread of drug-resistant genes in biofilms. Therefore, the behavior of resistant bacteria in the presence of antibiotics at sub-MICs should be investigated when using antibiotics.
Topics: Anti-Bacterial Agents; Bacitracin; Biofilms; DNA, Bacterial; Drug Resistance, Bacterial; Gene Transfer, Horizontal; Genes, Bacterial; Genes, MDR; Microbial Sensitivity Tests; Streptococcus mutans; Stress, Physiological
PubMed: 32532873
DOI: 10.1128/AEM.00770-20