Author(s): Athamna A, Athamna M, AbuRashed N, Medlej B, Bast DJ,
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Abstract OBJECTIVE: Long-term therapy for anthrax might induce antimicrobial resistance in Bacillus anthracis. The aim of the present study was to investigate the potential of 18 different antibiotics to select resistant isolates of B. anthracis, (ST-1 and Sterne strains). METHODS: Resistant isolates were selected by serial passages on brain heart infusion agar containing increasing concentrations of antibiotics (from the MIC upwards). RESULTS: The MICs of ciprofloxacin, ofloxacin and levofloxacin increased from 0.125-0.25 to 8 mg/L, that of moxifloxacin increased from 0.03-0.06 to 8 mg/L, in both strains, and the MIC of garenoxacin increased from 0.015 to 0.5 mg/L for the ST-1 strain and from 0.03 to 8 mg/L for the Sterne strain. The MICs of tetracycline and minocycline increased from 0.125 to 2-8 mg/L and 0.06 to 1 mg/L, respectively. The MIC of vancomycin increased from 2.5 to 20 mg/L for the ST-1 strain and from 5 to 20 mg/L for the Sterne strain. Linezolid exhibited an MIC increase from 2 to 4 mg/L for both strains. The MIC of quinupristin/dalfopristin increased from 0.125 to 64-128 mg/L. Erythromycin demonstrated an MIC increase from 1 to 128 mg/L, that of clarithromycin increased from 0.125 to 8-64 mg/L and that of telithromycin increased from 0.06-0.125 to 1-4 mg/L. The clindamycin MIC increased from 0.125-0.25 to 8 mg/L. Penicillin G and amoxicillin MICs increased from <1 mg/L to 128-512 mg/L. Isolates made resistant to one fluoroquinolone exhibited cross-resistance to the other quinolones except the ST-1 mutant strain which remained susceptible to garenoxacin. Cross-resistance to fluoroquinolones did not correlate with resistance to other antibiotics. CONCLUSION: The ease with which B. anthracis can be made resistant in vitro suggests that close monitoring of patients treated for anthrax is mandatory.
This article was published in J Antimicrob Chemother
and referenced in Journal of Bioterrorism & Biodefense
- Eugene Stephane Mananga
On Fer and Floquet-Magnus expansions: Application in solid-state nuclear magnetic resonance and physics
- Yosef Yarden
Classically, the 3âuntranslated region (3âUTR) is that region in eukaryotic protein-coding genes from the translation termination codon to the polyA signal. It is transcribed as an integral part of the mRNA encoded by the gene. However, there exists another kind of RNA, which consists of the 3âUTR alone, without all other elements in mRNA such as 5âUTR and coding region. The importance of independent 3âUTR RNA (referred as I3âUTR) was prompted by results of artificially introducing such RNA species into malignant mammalian cells. Since 1991, we found that the middle part of the 3âUTR of the human nuclear factor for interleukin-6 (NF-IL6) or C/EBP gene exerted tumor suppression effect in vivo. Our subsequent studies showed that transfection of C/EBP 3âUTR led to down-regulation of several genes favorable for malignancy and to up-regulation of some genes favorable for phenotypic reversion. Also, it was shown that the sequences near the termini of the C/EBP 3âUTR were important for its tumor suppression activity. Then, the C/EBP 3âUTR was found to directly inhibit the phosphorylation activity of protein kinase CPKC in SMMC-7721, a hepatocarcinoma cell line. Recently, an AU-rich region in the C/EBP 3âUTR was found also to be responsible for its tumor suppression. Recently we have also found evidence that the independent C/EBP 3âUTR RNA is actually exists in human tissues, such as fetal liver and heart, pregnant uterus, senescent fibroblasts etc. Through 1990âs to 2000âs, world scientists found several 3âUTR RNAs that functioned as artificial independent RNAs in cancer cells and resulted in tumor suppression. Interestingly, majority of genes for these RNAs have promoter-like structures in their 3âUTR regions, although the existence of their transcribed products as independent 3âUTR RNAs is still to be confirmed. Our studies indicate that the independent 3âUTR RNA is a novel non-coding RNA species whose function should be the regulation not of the expression of their original mRNA, but of some essential life activities of the cell as a whole.
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