Evolutionary relationship of the Bacillus licheniformis macrolide-lincosamide-streptogramin B resistance elements

Israeli-Reches, M.; Weinrauch, Yvette; Dubnau, David

doi:10.1007/bf00425545

Cited by 12 publications

(7 citation statements)

References 35 publications

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“…The primers we used to detect seven macrolide resistance genes would not be expected to capture all of the genes potentially conferring resistance. For example, primers for erythromycin resistance genes erm (D) and erm (34) previously characterized from B. licheniformis and B. clausii , respectively (Israeli-Reches et al, 1984; Bozdogan et al, 2004) were not included in our panel. Although we observed no increase in the diversity of erythromycin resistant nasopharyngeal bacteria in our study, determinants in those bacteria that possessed them could be disseminated into the broader environment.…”

Section: Discussionmentioning

confidence: 99%

Effect of subtherapeutic vs. therapeutic administration of macrolides on antimicrobial resistance in Mannheimia haemolytica and enterococci isolated from beef cattle

Zaheer¹,

Cook²,

Klima³

et al. 2013

Front. Microbiol.

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Macrolides are the first-line treatment against bovine respiratory disease (BRD), and are also used to treat infections in humans. The macrolide, tylosin phosphate, is often included in the diet of cattle as a preventative for liver abscesses in many regions of the world outside of Europe. This study investigated the effects of administering macrolides to beef cattle either systemically through a single subcutaneous injection (therapeutic) or continuously in-feed (subtherapeutic), on the prevalence and antimicrobial resistance of Mannheimia haemolytica and Enterococcus spp. isolated from the nasopharynx and faeces, respectively. Nasopharyngeal and faecal samples were collected weekly over 28 days from untreated beef steers and from steers injected once with tilmicosin or tulathromycin or continuously fed tylosin phosphate at dosages recommended by manufacturers. Tilmicosin and tulathromycin were effective in lowering (P < 0.05) the prevalence of M. haemolytica, whereas subtherapeutic tylosin had no effect. M. haemolytica isolated from control- and macrolide-treated animals were susceptible to macrolides as well as to other antibiotics. Major bacteria co-isolated with M. haemolytica from the nasopharynx included Pasteurella multocida, Staphylococcus spp., Acinetobacter spp., Escherichia coli and Bacillus spp. With the exception of M. haemolytica and P. multocida, erythromycin resistance was frequently found in other isolated species. Both methods of macrolide administration increased (P < 0.05) the proportion of erythromycin resistant enterococci within the population, which was comprised almost exclusively of Enterococcus hirae. Injectable macrolides impacted both respiratory and enteric microbes, whereas orally administered macrolides only influenced enteric bacteria.

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Section: Discussionmentioning

confidence: 99%

Effect of subtherapeutic vs. therapeutic administration of macrolides on antimicrobial resistance in Mannheimia haemolytica and enterococci isolated from beef cattle

Zaheer¹,

Cook²,

Klima³

et al. 2013

Front. Microbiol.

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“…Probes for nick translation were labeled with [O-32P]dATP as described previously (19 (21). The hybridization conditions used were those described previously (14). Autoradiograms were exposed at room temperature or at -70°C with intensifying screens (Cronex Lightning Plus; E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.…”

Section: Methodsmentioning

confidence: 99%

Cloning and characterization of the regulatory Bacillus subtilis competence genes comA and comB

Guillén¹,

Weinrauch²,

Dubnau³

1989

J Bacteriol

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comA and comB are Bacillus subtilis competence genes that are identified by insertions of Tn9171ac. They are classified as early genes because of their expression throughout growth; the expression of late com genes increases sharply during the transition to the stationary phase. The comA and comB determinants were cloned, and the 5' and 3' termini of their transcripts were localized by low-resolution S1 nuclease protection experiments. comA and comB were found by Southern blotting to be localized near one another, but they were nevertheless apparently transcribed independently. Epistatic relationships among the com genes were explored by using the j-galactosidase expressed from transcriptional fusions as a marker. Late com genes were found to be dependent on the products of comA, comB, and sin for their expression. The sin gene is a transcriptional regulator that is required for the development of competence

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“…Plate transformation was carried out as described elsewhere (15 (27). Filters were hybridized as described previously (17). Autoradiograms were exposed at -70°C with Cronex Lightning Plus (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.)…”

mentioning

confidence: 99%

Cloning and characterization of a cluster of linked Bacillus subtilis late competence mutations

Albano¹,

Dubnau²

1989

J Bacteriol

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We characterized a segment of chromosomal DNA from Bacillus subtilis that was required for the development of genetic competence. The chromosomal DNA was cloned from a group of genetically linked and phenotypically similar Tn9171ac insertion mutants deficient in competence. This cluster of mutations defined the comG locus. Chromosomal DNA flanking each of the six insertions was cloned. Restriction maps of the cloned plasmids revealed that their chromosomal inserts consisted of overlapping fragments. These data, together with Southern blots of chromosomal DNA from the comG mutants, showed that the six Tn9171ac comG insertions occurred in the following order: comG12, comG39, comG412, comG107, comG56, and comG210. Expression of the comG Tn9171ac insertions was from a promoter located upstream from the first insertion, comG12. This was determined genetically and by low-resolution S1 nuclease mapping of the 3' terminus. The comG region spanned about 5 kilobase pairs, based on low-resolution S1 nuclease mapping of the transcription terminator and Northern blotting. The comG12 mutation had a partial epistatic effect on the expression of one other com locus, comE, but none of the other comG mutations affected expression of this or any other com gene tested. Based on these conclusions, and on its size and phenotype, the comG locus must be organized as a polycistronic operon that is subject to competence-specific regulation.Genetic competence in Bacillus subtilis is an example of a regulated global response to environmental conditions and developmental signals. The final products of this regulated response are also of interest, because they are presumably required for the binding, processing, and transport of DNA from the medium into the cytosolic compartment. Little is known about these products or the specific roles they play (for a review, see reference 8), and it is of interest to characterize them on the molecular level. 30,32) provided us with powerful and convenient tools for cloning comnG DNA from B. subtilis. We were able to clone Tn9171ac insertion proximal chromosomal DNA from each of the six insertion mutants, obtaining in all about 6.5 kilobase pairs (kbp) of B. subtilis chromosomal DNA. We were also able to clone an intact region of comG DNA that was devoid of insertional disruptions and that consisted of about 8.5 kbp. We analyzed the cloned fragments by restriction mapping and determined the linear order of the six insertion positions in the comG region by Southern blotting. The epistatic relationships between comG and other competence genes were examined.(The work by M.A. was conducted in partial fulfillment of the requirements for the doctoral degree from the Department

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Evolutionary relationship of the Bacillus licheniformis macrolide-lincosamide-streptogramin B resistance elements

Cited by 12 publications

References 35 publications

Effect of subtherapeutic vs. therapeutic administration of macrolides on antimicrobial resistance in Mannheimia haemolytica and enterococci isolated from beef cattle

Effect of subtherapeutic vs. therapeutic administration of macrolides on antimicrobial resistance in Mannheimia haemolytica and enterococci isolated from beef cattle

Cloning and characterization of the regulatory Bacillus subtilis competence genes comA and comB

Cloning and characterization of a cluster of linked Bacillus subtilis late competence mutations

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