Comparison of clinical and environmental isolates of Legionella pneumophila obtained in the UK over 19 years

ABSTRACTBetween January 1980 and December 1998, 3458 cases of Legionnaires’ disease were reported to the national surveillance scheme in England and Wales. Of these, 463 (13.4%) were reported as proven by culture and isolation of Legionella spp., with 96.3% being Legionella pneumophila. Serogroup (Sgp), monoclonal antibody (mAb) subgrouping and restriction fragment length polymorphism (RFLP) analysis data were obtained for 321 (69.3%) of these, of which 284 were classified as being unrelated to any other isolate in the study. Typing data were also available for 117 unrelated environmental isolates of L. pneumophila obtained from England and Wales, giving a total of 401 unrelated isolates in the study. Of the clinical isolates, 88.0% were Sgp1, compared with only 42.7% of environmental isolates (p <0.001); 79.6% of clinical isolates were subgrouped as mAb2+, compared with only 12.8% of environmental isolates (p <0.001). RFLP typing identified 67 types among the 401 isolates, with clinical isolates showing significantly less diversity than environmental isolates (index of diversity (IOD) 0.944 vs. 0.958; p <0.05), with three RFLP types (1, 5 and 14) accounting for 40.0% of all clinical isolates. Combining the phenotypic and genotypic data resulted in 173 distinct phenons, with clinical isolates showing significantly less diversity than environmental isolates (IOD 0.964 vs. 0.996; p <0.01). Three phenons accounted for 30% of all clinical isolates. These data strongly suggest that some strains of L. pneumophila are more likely to cause human infection than would be expected from their distribution in the environment

Assessment of fluorescent amplified fragment length polymorphism analysis for epidemiological genotyping of Legionella pneumophila serogroup 1

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Pertactin-deficient Bordetella pertussis isolates: evidence of increased circulation in Europe, 1998 to 2015

Introduction: Pertussis outbreaks have occurred in several industrialised countries using acellular pertussis vaccines (ACVs) since the 1990s. High prevalence of pertactin (PRN)-deficient Bordetella pertussis isolates has been found in these countries. Aims: To evaluate in Europe: (i) whether proportions of PRN-deficient strains increased in consecutive collections of B. pertussis clinical isolates; (ii) if the frequency of PRN-deficient strains in countries correlated with the time since ACV introduction; (iii) the presence of pertussis toxin (PT)-, filamentous haemagglutinin (FHA)- or fimbriae (Fim)-deficient isolates. Methods: B. pertussis clinical isolates were obtained from different European countries during four periods (EUpert I-IV studies): 1998 to 2001 (n =102), 2004 to 2005 (n =154), 2007 to 2009 (n =140) and 2012 to 2015 (n=265). The isolates' selection criteria remained unchanged in all periods. PRN, PT, FHA and Fim2 and Fim3 expression were assessed by ELISA. Results: In each period to1.0% (1/102), 1.9% (3/154), 6.4% (9/140) and 24.9% (66/265) of isolates were PRN-deficient. In EUpert IV, PRN-deficient isolates occurred in all countries sampled and in six countries their frequency was higher than in EUpert III (for Sweden and the United Kingdom, p < 0.0001 and p = 0.0155, respectively).Sweden and Italy which used ACvs since the mid 1990s had the highest frequencies (69%; 20/29 and 55%; 11/20, respectively) while Finland, where primary immunisations with ACV containing PRN dated from 2009 had the lowest (3.6%). Throughout the study, no PT- or FHA-deficient isolate and one Fim2/3-deficient was detected. Conclusion: Results suggest that the longer the period since the introduction of ACVs containing PRN, the higher the frequency of circulating PRN-deficient isolates

Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Measurement of the CP-Violating Asymmetry Amplitude sin2β\beta

We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes

Measurement of the electron energy spectrum and its moments in inclusive B -> Xe nu decays

We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million Y(4S)-->B(B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cutoffs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be B(B-->Xenu,E-e>0.6 GeV)=[10.36+/-0.06(stat.)+/-0.23(sys.)]%