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91.
Lutfiye Oksuz Celine Dupieux Anne Tristan Michele Bes Jerome Etienne Nezahat Gurler 《International journal of medical sciences》2013,10(12):1740-1745
Background: To characterize the methicillin-resistant Staphylococcus aureus (MRSA) clones present in Istanbul, 102 MRSA isolates collected during a 5-year period at the Istanbul Medical Faculty Hospital were characterized using microarray analysis and phenotypic resistance profiles.Methods: Resistance to methicillin was detected with a cefoxitin disk diffusion assay and confirmed with a MRSA-agar and MRSA detection kit. Antimicrobial susceptibility testing was performed by a disk diffusion assay and interpreted according to the 2012 guidelines of the Antibiogram Committee of the French Society for Microbiology. Decreased susceptibility to glycopeptides was confirmed using the population analysis profile-area under the curve (PAP-AUC) method. The presence of the mecA gene was detected by polymerase chain reaction. Bacterial DNA was extracted according to the manufacturer''s recommended protocol using commercial extraction kits. Strains were extensively characterized using the DNA microarray.Results: Isolates were grouped into six clonal complexes. The most frequently detected clone was the Vienna/Hungarian/Brazilian clone (ST239-MRSA-III), which accounted for 53.9% of the isolates. These isolates were resistant to multiple antibiotics, particularly penicillin, tetracycline, rifampicin, kanamycin, tobramycin, gentamicin, levofloxacin, erythromycin, lincomycin and fosfomycin. Furthermore, three isolates were detected by population analysis profile as heterogeneous vancomycin-intermediate S. aureus (hVISA). The UK-EMRSA-15 clone (ST22-MRSA-IV PVL negative) was detected in 9.8% of the isolates and was mainly susceptible to all anti-staphylococcal antibiotics. Seven isolates (6.9%) were positive for PVL genes and were assigned to the CC80-MRSA-IV clone (European CA-MRSA clone, three isolates), ST8-MRSA-IV clone (USA300 clone, two isolates, one ACME-positive) or ST22-MRSA-IV clone (“Regensburg EMRSA” clone, two isolates). All other clones were detected in one to six isolates and corresponded to well-known clones (e.g., Pediatric clone, Dublin EMRSA clone, WA MRSA-54/63, WA MRSA-1/57).Conclusions: This work highlighted both the high prevalence of ST239-MRSA-III clone and the large diversity of the other MRSA clones detected in a university hospital in Istanbul. 相似文献
92.
Antigenic diversity and size diversity of Plasmodium falciparum antigens in isolates from Gambian patients. I. S-antigens 总被引:2,自引:2,他引:2
RUSSELL J. HOWARD LINDSEY J. PANTON† KEVIN MARSH† IRENE T. LING‡ J ELLEN J. WINCHELL‡ R. J. M. WILSON‡ 《Parasite immunology》1986,8(1):39-55
Ring-stage asexual parasites of P. falciparum were collected from six Gambian children and the S-antigens radiolabelled by 3H-glycine uptake during in vitro culture up to rupture of infected cells and merozoite release. Ouchterlony double diffusion of boiled culture supernatants against a panel of adult Gambian sera identified one S-antigen precipitin arc for five isolates and two precipitin arcs for one isolate. Five of the six isolates were serologically distinct. Analysis of S-antigens by comparison of SDS-polyacrylamide gel electrophoresis patterns of heat-treated soluble proteins revealed a more complex pattern of 3H-labelled S-antigens that was different for each isolate. There were between two and six different 3H-labelled bands for each isolate in the size range of molecular weight 137 000 to 285 000. This result confirms the large size range of S-antigens identified with culture adapted P. falciparum. Several bands were relatively weakly labelled with 3H-glycine, suggesting that natural isolates contain one or two predominant S-antigen phenotypes and several other S-antigen phenotypes expressed by minor parasite subpopulations. Immunoprecipitation was performed using a panel of sera from Gambian adults, or, acute and 3 week convalescent sera from the same patients used for S-antigen radiolabelling. Adult sera generally immunoprecipitated some of the S-antigens in each isolate, including antigens that must represent extremely minor parasite subpopulations since they could not be seen in the patterns of non-immunoprecipitated heat-stable proteins. Sera from convalescent children were generally negative on immunoprecipitation, even with the homologous isolate. In one case we observed the acquisition of specific immunoprecipitating antibody to one of the homologous S-antigens during the convalescent period. The antigenic and structural complexity of S-antigens in natural isolates that have not been submitted to the selection pressure of adaptation for in vitro culture is clearly greater than for culture adapted P. falciparum. 相似文献
93.
A. Desvars Y. Grimaud H. Guis O. Esnault X. Allène L. Gardès T. Balenghien T. Baldet J.C. Delécolle C. Garros 《Acta tropica》2015
This study establishes the first faunistic inventory of livestock associated Culicoides (Diptera: Ceratopogonidae) species of Reunion Island (Indian Ocean), where bluetongue and epizootic hemorrhagic disease are regularly recorded. Single night-catches were performed at 41 sites using light suction traps at altitudes ranging from 0 to 1525 m, from March to April 2005. Five species were recorded: Culicoides imicola, Culicoides bolitinos, Culicoides enderleini, Culicoides grahamii, and Culicoides kibatiensis, among which at least the first three species are known to be involved in virus transmission to ruminants and equids. This is the first record of C. bolitinos, C. kibatiensis, and C. enderleini on the island. C. imicola was the most abundant species along the sea coast. C. bolitinos was more abundant inland and on two sites on the east coast. C. kibatiensis and C. grahamii were less abundant than the other three species and limited to two foci. 相似文献
94.
BackgroundCrimean Congo hemorrhagic fever (CCHF) has been reported from more than 30 countries in Africa, Asia, Eastern Europe and Middle East. The disease is considered endemic in Pakistan and neighboring countries like Iran and Afghanistan.ObjectivesThis study aimed to explore the genetic diversity of CCHF virus (CCHFV) detected in Pakistan and Afghanistan based on analysis of partial S-segment sequences.Study designDuring 2011, one hundred samples satisfying the CCHF case definition were tested by (ELISA) and RT-PCR for detection of IgM antibodies and viral RNA, respectively. Phylogenetic analysis was carried out on partial S-segment nucleotide sequences using MEGA 5.0.ResultsOut of one hundred collected during 2011, 49 (49%) were positive for CCHF either by ELISA/RT-PCR or both. The mean age of the CCHFV positive cases was 30.32 years (range 18–56 years) and overall mortality rate was 20.4%. All CCHF virus isolates from this study clustered with strains previously reported from Pakistan, Iran and Afghanistan within the Asia-1 genogroup. Four distinct sub-clades were found circulating within Asia-1 genogroup. Six CCHFV strains found in Pakistan and Afghanistan grouped into a new sub-clade-D.ConclusionsData from this study shows that endemic foci of CCHFV span the international border between Pakistan and Afghanistan with genetically diverse variants circulating in this region. Our findings emphasize to establish a laboratory based surveillance program and devise health policy measures to control CCHF infection especially in Baluchistan. 相似文献
95.
目的:探讨糠酸莫米松鼻喷雾剂对儿童变应性鼻炎鼻腔黏液菌群的影响,并观察其临床疗效。方法选取我院门诊治疗的49例变应性鼻炎儿童患者作为治疗组,给予糠酸莫米松治疗,同时对其治疗前后鼻腔黏液的菌群分布情况进行检测,另设立48例未患变应性鼻炎的正常儿童为对照组进行比较。结果治疗组患者经糠酸莫米松治疗后鼻部症状、眼部症状、呼吸道症状评分均较治疗前明显降低(P<0.05),治疗组治疗后鼻部症状、眼部症状、呼吸道症状得分均高于对照组(P<0.05)。经检测发现,对照组病原菌检出率为91.7%,其中需氧菌和真菌各占82.4%和17.6%,而治疗组治疗前病原菌检出率为91.8%,需氧菌和真菌各占79.6%和20.4%,治疗后病原菌检出率为93.9%,其中需氧菌和真菌各占85.4%和14.6%,其中需氧菌以凝固酶阴性葡萄球菌居首位,真菌则以曲霉菌居首位。但对照组与治疗组治疗前以及治疗组治疗前后比较差异均无统计学意义(P>0.05)。结论糠酸莫米松鼻喷雾剂治疗儿童变应性鼻炎对改善患儿的临床症状有较好效果,但对鼻腔黏液菌群不产生明显影响。 相似文献
96.
97.
随着慢性肾病(chronic kidney disease,CKD)发病率不断增加,肾病已成为全球性重大公共卫生问题之一。据2017世界肾脏大会发布的最新全球肾病健康报告显示,全球每10人当中就有1人患有肾脏疾病[1]。近年来,越来越多的证据表明,慢性肾病患者中存在肠道菌群失调及肠道屏障功能受损的情况,且慢性肾病患者比非慢性肾病患者有更高的患痴呆和认知障碍的风险。本文就肠道菌群和脑-肠-肾轴在慢性肾脏疾病中的作用做一综述,希望通过调节肠道菌群作为靶点,来延缓慢性肾脏病及其并发症的进展。 相似文献
98.
Xue-Feng Wang Shuai Wang Qiang Liu Yue-Zhi Lin Cheng Du Yan-Dong Tang Lei Na Xiaojun Wang Jian-Hua Zhou 《Viruses》2014,6(11):4265-4279
Equine infectious anemia virus (EIAV) is a member of the Lentivirus genus in the Retroviridae family that exhibits a genomic structure similar to that of HIV-1. The S2 accessory proteins play important roles in viral replication in vivo and in viral pathogenicity; however, studies on S2 evolution in vivo are limited. This study analyzed the evolutionary characteristics of the S2 gene of a pathogenic EIAV strain, EIAVLN40, in four experimentally infected horses. The results demonstrated that 14.7% (10 of 68 residues) of the stable amino acid mutations occurred longitudinally in S2 during a 150-day infection period. Further analysis revealed that six of the ten mutated residues were positively selected during the infection. Alignment and phylogenetic analyses showed that the S2 gene sequences of viruses isolated from the infected horses at the early stage of EIAVLN40 infection were highly homologous and similar to the vaccine-specific sequence. The S2 gene variants isolated from the febrile episodes and late phase of infection became homologous to the S2 gene sequence of the inoculating EIAVLN40 strain. Our results indicate that the S2 gene evolves in diversity and divergence in vivo in different stages of EIAV infection and that this evolution correlates with the pathogenicity of the virus. 相似文献
99.
Biswadeep Das Aparna P. Patra Mumani Das Namita MahapatraHarekrushna Tripathy Santanu K. KarRupenangshu K. Hazra 《Acta tropica》2014
Anopheles annularis is one of the major vectors of malaria in Odisha, India. The present study was undertaken to determine the vectorial capacity and assess the genetic diversity of An. annularis collected from different endemic regions of Odisha. Mosquitoes were collected from thirteen endemic districts using standard entomological collection methods from 2009 to 2011. Sibling species of An. annularis were identified by PCR-RFLP and sequencing of D3 region of 28S ribosomal DNA (rDNA) region. Plasmodium falciparum (Pf) sporozoite rate and human blood fed percentage (HBF) were estimated by multiplex PCR using Pf and human specific primers. Genetic diversity of An. annularis was estimated by ISSR markers. Out of 1647 An. annularis collected, 1353 (82.15%) were collected by mechanical aspirators and 294 (17.85%) by light trap. 49 (2.97%) were positive for human blood and 18 (1.09%) were positive for Pf sporozoite. PCR-RFLP and sequencing analyses detected only An annularis A in the study areas. Overall genetic differentiation among An. annularis populations was moderate (FST = 0.048) and showed significant correlation between genetic distance and geographic distance (r = 0.882; P < 0.05). Angul population proved to be genetically unique and was highly divergent FST > 0.110) from other populations, suggesting low gene flow between them. The study indicated that only An. annularis A was found in Odisha with potential vectorial capacity that can play a major role in malaria transmission. ISSR markers proved to be useful molecular tools to evaluate genetic variability in An. annularis populations. 相似文献
100.
Peter T. Green Kyle E. Harms Joseph H. Connell 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(52):18649-18654
A variety of ecological processes influence diversity and species composition in natural communities. Most of these processes, whether abiotic or biotic, differentially filter individuals from birth to death, thereby altering species’ relative abundances. Nonrandom outcomes could accrue throughout ontogeny, or the processes that generate them could be particularly influential at certain stages. One long-standing paradigm in tropical forest ecology holds that patterns of relative abundance among mature trees are largely set by processes operating at the earliest life cycle stages. Several studies confirm filtering processes at some stages, but the longevity of large trees makes a rigorous comparison across size classes impossible without long-term demographic data. Here, we use one of the world’s longest-running, plot-based forest dynamics projects to compare nonrandom outcomes across stage classes. We considered a cohort of 7,977 individuals in 186 species that were alive in 1971 and monitored in 13 mortality censuses over 42 y to 2013. Nonrandom mortality with respect to species identity occurred more often in the smaller rather than the larger size classes. Furthermore, observed nonrandom mortality in the smaller size classes had a diversifying influence; species richness of the survivors was up to 30% greater than expected in the two smallest size classes, but not greater than expected in the larger size classes. These results highlight the importance of early life cycle stages in tropical forest community dynamics. More generally, they add to an accumulating body of evidence for the importance of early-stage nonrandom outcomes to community structure in marine and terrestrial environments.Processes that operate nonrandomly with respect to species identity contribute to the structure of natural communities (1–3). Evidence from diverse rain forests includes demographic transitions from seeds to seedlings (4, 5), at the seedling (6, 7) and sapling stages (8) and among large trees (9–12). Although the relative contributions of nonrandom processes at each life cycle stage to determining patterns of abundance and diversity in the mature canopy are unknown, one long-standing paradigm is that community assembly is mediated primarily by events occurring from seed dispersal through seedling germination and small-sapling establishment (13–17). However, despite suggestive patterns (6, 7, 18, 19), evidence is lacking for the comparative strength of early-stage dynamics in determining canopy abundance and diversity.Numerous studies demonstrate significant interspecific variation in the susceptibility of tropical tree seedlings to postgermination hazards, including natural enemies (20, 21), adverse climatic or edaphic conditions (22), physical damage (23), and the crowding or shared-enemies effects of con- and heterospecific neighbors (24, 25). In other words, the per capita probability of seedling mortality is nonrandom because the probability of death is not the same for all individuals in a local community – it is dependent to some degree on species identity. In plant communities in which generation times are relatively short, experiments have demonstrated that nonrandom mortality through these early transitions can be sufficiently strong to affect the species composition of mature plants (26–29). Such demonstrations are impossible in studies of a few decades or less in duration when generation times are long and even juveniles live for several decades or centuries, such as in many tropical forests. Even so, some hypotheses explicitly identify stressors that affect plants at the earliest life cycle stages (such as pests and pathogens, 13, 14, 30) as disproportionately influential. In addition, some empirical studies find a lack of support for nonrandom processes operating among larger stems (31, 32). Together these hypotheses and observations provide the rationale underpinning the considerable body of research on seed and seedling dynamics in tropical forests worldwide. However, no empirical or experimental assessment has been made of the relative contributions across life cycle stages from nonrandom mortality.Here, we evaluate the comparative contribution of early-stage dynamics using a multidecadal study of a tropical forest dynamics plot initiated by one of us (J.H.C.) in 1963 at a site in north Queensland, Australia. We considered a cohort of 7,977 individuals in 186 species that were alive on the plot in 1971, from tiny seedlings to large canopy trees, whose fates were monitored in 13 mortality censuses over 42 y to 2013. Individuals were assigned to one of six size classes (Size class* N in 1971 S in 1971 S in 2013 D in 2013 (% mortality) SC1 (0-6.0-cm ht) 1,465 91 24 1,421 (97.0) SC2 (6.1–15.2-cm ht) 1,275 105 47 1,156 (90.7) SC3 (15.3–36.6-cm ht) 1,291 106 77 965 (74.7) SC4 (36.7–182.9-cm ht) 1,351 124 101 639 (47.3) SC5 (183.0-cm ht – 10-cm dbh) 1,208 135 123 330 (27.3) SC6 (≥10.1-cm dbh) 1,387 122 113 357 (25.7)