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41.
J. Donaghy M. Keyser J. Johnston F.P. Cilliers P.A. Gouws M.T. Rowe 《Letters in applied microbiology》2009,49(2):217-221
Aims: To determine the effect of UV radiation on the viability of two strains of Mycobacterium avium ssp. paratuberculosis (Map) inoculated into milk.
Methods and Results: Mycobacterium avium ssp. paratuberculosis in a ultra heat treated milk matrix was subjected to increasing doses of UV-C radiation from 0 to 1836 mJ ml−1 using a pilot-scale UV reactor (20 l capacity). Survival of Map was monitored by culture on Herrold's egg yolk medium, Middlebrook 7H10 medium and the FASTPlaque TB™ phage assay. Differences in sensitivity to UV treatment were observed between strains, however, at 1000 mJ ml−1 a Map kill rate of 0·1–0·6 log10 was achieved regardless of strain used or method employed to enumerate Map. Although the inactivation trend was similar on the culture and phage assay, the former gave a consistently higher viable count.
Conclusions: The use of UV radiation alone does not represent an alternative to current pasteurization regimes for a large reduction in viable Map in milk.
Significance and Impact of the Study: To the authors' knowledge the work here represents the first pilot-scale UV treatment process used to assess UV efficacy to inactivate Map in milk. The results are similar to those obtained with a laboratory-scale process indicating the difficulties associated with UV treatment of an opaque liquid and the recalcitrance of Map towards inimical treatments. 相似文献
Methods and Results: Mycobacterium avium ssp. paratuberculosis in a ultra heat treated milk matrix was subjected to increasing doses of UV-C radiation from 0 to 1836 mJ ml
Conclusions: The use of UV radiation alone does not represent an alternative to current pasteurization regimes for a large reduction in viable Map in milk.
Significance and Impact of the Study: To the authors' knowledge the work here represents the first pilot-scale UV treatment process used to assess UV efficacy to inactivate Map in milk. The results are similar to those obtained with a laboratory-scale process indicating the difficulties associated with UV treatment of an opaque liquid and the recalcitrance of Map towards inimical treatments. 相似文献
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43.
Chrisna Veldsman Marleen M. Kock Theresa Rossouw Martin Nieuwoudt Mark Maeurer Anwar A. Hoosen & Marthie M. Ehlers 《FEMS immunology and medical microbiology》2009,57(3):269-273
Tuberculosis is a life-threatening infection worldwide. Despite improvements in therapy, it results in 2 million deaths and 9 million new cases annually. This study evaluated the use of the QuantiFERON-TB GOLD enzyme-linked immunosorbent assay in a high HIV/TB burden setting in an ARV clinic at the Tshwane District Hospital, South Africa. The sensitivity and specificity of the QF assay in the clinic were 30% (9/30) and 63% (19/30), respectively, when compared with the gold standard culture results. Analysis also suggested that the sensitivity of the QuantiFERON assay is determined by a limiting patient CD4 value between 150 and 200. 相似文献
44.
The freshwater isopod Paramphisopus palustris is ubiquitous and abundant in the groundwater-fed wetlands of the Swan Coastal Plain around Perth, Western Australia. Taxonomically,
an additional variety (P. palustris fairbridgei) and species (P. montanus) are recognized from geographically outlying localities. Here a 486 bp fragment of cytochrome c oxidase subunit I (COI) mtDNA was sequenced in 68 individuals from 23 localities in order to evaluate the accepted taxonomy,
to examine the evolutionary history of the species, and to identify lineages to prioritize conservation of wetlands already
substantially modified. MtDNA showed individual populations to be largely distinct and differentiated. The 41 unique haplotypes
formed seven independent, geographically defined networks. Phylogenetic analysis retrieved corresponding subclades, with three
well-supported larger clades occurring (1) north of the Swan River, (2) south of the Swan River, and (3) in an area further
south. A clear pattern of isolation by distance was detected suggesting an ancient serial founder event, with the pattern
possibly persisting in the face of limited gene flow through priority effects. The possibility of incipient speciation, the
monophyly of the recognized subspecies and the paraphyly of P. palustris with respect to P. montanus, suggest that the current taxonomy is invalid and requires re-examination. Divergences suggest a mid- to early Pliocene divergence
of the major clades, with early Pliocene divergences among subclades probably driven by documented intense arid periods. Lineages
are present in wetlands in geologically younger environments suggesting in situ survival and persistence. Seven Evolutionarily
Significant Units were identified for the conservation of Paramphisopus, two of which are not currently represented in conservation reserves. With increased water demand and the negative impact
of surrounding land-use, the current study provides a first phylogeographic assessment of conservation priorities for wetlands
of the Swan Coastal Plain.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material which is available to authorized users.
Handling editor: C. Sturmbauer 相似文献
45.
Marthie M. Ehlers Chrisna Veldsman Eddy P. Makgotlho Michael G. Dove Anwar A. Hoosen & Marleen M. Kock 《FEMS immunology and medical microbiology》2009,56(3):191-196
Extended-spectrum β-lactamases (ESBLs) are considered to be one of the most important antibiotic resistance mechanisms. This study reported the ESBL-producing genes in 53 randomly selected clinical bacterial isolates from the Steve Biko Academic Hospital. The presence of the bla SHV , bla TEM and bla CTX-M genes was determined, and the overall prevalence of these genes detected in this study was 87% (46/53) in comparison with the literature; these results were higher when compared with 33% for Escherichia coli in Europe and 0.8% in Denmark for similar pathogens. These research findings indicated that it is crucial to routinely monitor the prevalence of these resistance genes. 相似文献