4,378 research outputs found

    Correlation of ciprofloxacin resistance with the AdeABC efflux system in Acinetobacter baumannii clinical isolates

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    Background: Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients. Methods: A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI). Results: Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to ≥128 μg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system. Conclusions: The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI. © The Korean Society for Laboratory Medicin

    Sharing Alike: French Family Taxation as a Model for Reform

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    The current system of federal income taxation neither recognizes nor accommodates the realities of the modern American family. The author proposes an alternative method of taxing personal income based on the French method of taxation. The French method of taxing each family member\u27s portion of total family income in the aggregate according to a universal rate schedule is examined as a model that better reflects the actual living arrangements and financial burdens of American taxpayers

    Detection of the efflux-mediated erythromycin resistance transposon in streptococcus pneumoniae

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    Background: The present analysis focuses on phenotypic and genotypic characterizations of efflux-mediated erythromycin resistance in Streptococcus pneumoniae due to an increase in macrolide resistance in S. pneumoniae worldwide. Methods: We investigated the prevalence of efflux-mediated erythromycin resistance and its relevant genetic elements from 186 specimens of S. pneumonia isolated from clinical and normal flora from Tehran, Iran. The presence of erythromycin resistance genes was tested by PCR with two sets of primers, specific for erm(B) and mef(A/E), and their genetic elements with tetM, xis, and int genes. Isolates were typed with the BOX PCR method and tested for resistance to six antibiotics. Results: Antibiotic susceptibility tests revealed that 100 and 47 isolates were resistant to tetracycline and erythromycin, respectively. The erythromycin and clindamycin double-disc diffusion test for macrolide-lincosamide-streptograminB (MLSB) resistance phenotype showed 74 (84) isolates with the constitutive MLSB phenotype and the remaining with the M phenotype. BOX PCR demonstrated the presence of 7 types in pneumococci with the M phenotype. Fourteen (16) isolates with the M phenotype harbored mef(A/E), tetM, xis, and int genes. Conclusion: The present results suggest dissemination of polyclonal groups of S. pneumoniae with the M phenotype carrying resistance genes attributed to transposon 2009. © The Korean Society for Laboratory Medicine

    Multipartite entanglement in fermionic systems via a geometric measure

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    We study multipartite entanglement in a system consisting of indistinguishable fermions. Specifically, we have proposed a geometric entanglement measure for N spin-1/2 fermions distributed over 2L modes (single particle states). The measure is defined on the 2L qubit space isomorphic to the Fock space for 2L single particle states. This entanglement measure is defined for a given partition of 2L modes containing m >= 2 subsets. Thus this measure applies to m <= 2L partite fermionic system where L is any finite number, giving the number of sites. The Hilbert spaces associated with these subsets may have different dimensions. Further, we have defined the local quantum operations with respect to a given partition of modes. This definition is generic and unifies different ways of dividing a fermionic system into subsystems. We have shown, using a representative case, that the geometric measure is invariant under local unitaries corresponding to a given partition. We explicitly demonstrate the use of the measure to calculate multipartite entanglement in some correlated electron systems. To the best of our knowledge, there is no usable entanglement measure of m > 3 partite fermionic systems in the literature, so that this is the first measure of multipartite entanglement for fermionic systems going beyond the bipartite and tripartite cases.Comment: 25 pages, 8 figure
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