scholarly journals A simple model for the influence of habitat resource availability on lateral clonal spread

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150327 ◽  
Author(s):  
Martin Weiser ◽  
Jan Smyčka
Keyword(s):  
Simple Model ◽  
Resource Availability ◽  
Clonal Growth ◽  
Null Model ◽  
Availability Analysis ◽  
Optimal Distance ◽  
High Prevalence ◽  
Below Ground ◽  
Clonal Spread ◽  
Plant Community Assembly

Plant clonal spread is ubiquitous and of great interest, owing both to its key role in plant community assembly and its suitability for plant behaviour research. However, mechanisms that govern spreading distance are not well known. Here we link spacer costs and below-ground competition in a simple model of growth in a homogeneous below-ground environment, in which optimal distance between ramets is based on minimizing the sum of these costs. Using this model, we predict a high prevalence of clonal growth that does not employ spacers in resource-poor environments and a nonlinear increase in spreading distance in response to increasing below-ground resource availability. Analysis of database data on clonal growth in relationship to below-ground resource availability revealed that patterns of the spread based on stolons is compatible with the model's predictions. As expected, model prediction failed for rhizomatous species, where spacer sizes are likely to be selected mainly to play roles other than spread. The model's simplicity makes it useful as a null model in testing hypotheses about the effects of environmental heterogeneity on clonal spread.

scholarly journals 159. Genomic Epidemiology of MRSA at Intake to a Large Inner-City Jail: Evidence for Community Transmission Networks?

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S13-S14 ◽  
Author(s):  
Kyle J Popovich ◽  
Evan S Snitkin ◽  
Stefan J Green ◽  
Alla Aroutcheva ◽  
Michael Schoeny ◽  
...  
Keyword(s):  
Cook County ◽  
Hiv Care ◽  
Transmission Networks ◽  
Genomic Epidemiology ◽  
High Prevalence ◽  
Community Transmission ◽  
Clonal Spread ◽  
Small Clusters ◽  
The Impact ◽  
Mrsa Colonization

Abstract Background USA300 is endemic in the community, with congregate settings potentially facilitating spread. The impact of community MRSA transmission networks on importation of MRSA into urban jails is unknown. We examined MRSA colonization isolates entering the jail and determined whether there are community transmission networks for MRSA that precede incarceration. Methods HIV-infected and HIV-negative males incarcerated at the Cook County Jail were enrolled within 72 hours of intake. Surveillance cultures (nares, throat, and groin) were collected to determine prevalence of MRSA colonization. A survey was administered to identify predictors of colonization. Whole-genome sequencing (WGS) and phylogenetic analysis were integrated with epidemiologic data to identify community transmission networks. Results A total of 800 males were enrolled (83% AA and 9% Hispanic); 58% were HIV-infected. The prevalence of MRSA colonization at intake was 19%. In multivariate analysis, methamphetamine use (METH), unstable housing, and prior jail incarceration were significant predictors of MRSA. Among HIV patients, injection drug use and HIV care at outpatient Clinic A that emphasize comprehensive care to the LGBTQ community were significant predictors of MRSA. Of the 31 (45%) patients with care at Clinic A, 14 had MRSA colonization. We sequenced 145 isolates from unique individuals, with 102 and 13 closely related to USA300 and USA500 reference genomes, respectively. USA300 strains from intake were diverse (median pairwise SNV distance = 109), with several small clusters noted. WGS revealed the high prevalence of MRSA in Clinic A was not due to clonal spread but rather an intermingling of distinct community transmission networks (strains were highly diverse; median pairwise SNV distance = 410). We did identify a 13-member community transmission network underlying spread of USA500 (figure). Members of this network were more likely to be HIV-infected (P < 0.004), MSM (P < 0.001), and METH (P < 0.001). Conclusion A high proportion of individuals enter jail already colonized with MRSA and colonization risk factors provide clues to community reservoirs for MRSA. WGS extended epidemiologic analysis and revealed community transmission networks that could be a potential focus for an intervention. Disclosures All authors: No reported disclosures.

Insight into neonatal septicaemicEscherichia colifrom India with respect to phylogroups, serotypes, virulence, extended-spectrum-β-lactamases and association of ST131 clonal group

2015 ◽  
Vol 143 (15) ◽  
pp. 3266-3276 ◽  
Author(s):  
S. ROY ◽  
S. DATTA ◽  
P. DAS ◽  
R. GAIND ◽  
T. PAL ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Virulence Determinants ◽  
E Coli ◽  
Extended Spectrum ◽  
High Prevalence ◽  
Clonal Spread ◽  
Insight Into ◽  
Esbl Producers ◽  
St131 Clone

SUMMARYThe study characterizes a collection of 67 neonatal septicaemicEscherichia coliisolates on the basis of phylogroup, serotype, virulence, antibiotic resistance and also the association of CTX-M-producingE. coliand the ST131 clone in a developing country. Phylogroups B2 and D were predominant (33% and 19%, respectively). The most prevalent virulence factors (VFs) weretraT(69%) andiucC(68%) and most VFs were concentrated in the B2 isolates. High levels of resistance (⩾70%) to cefotaxime, ciprofloxacin and trimethoprim/sulfamethoxazole was recorded but meropenem remained the most active antimicrobial. Six (9%) of the study isolates belonged to the ST131 clone, five of which were from the same hospital, and were either indistinguishable or closely related by pulsed-field gel electrophoresis. Although the prevalence of CTX-M-15-producing isolates was high (81%), the ST131 clone was relatively infrequent (11%) in extended spectrumβ-lactamase (ESBL)-producers. The ST131 clone was characterized by the presence ofblaCTX-M-15,qnrS, aac(6′)-Ib-cr, IncF plasmids and virulence determinants such asiucC, papC, traT, usp, hlyA, iroNE.coli,cnf, andsat. We conclude that clonal spread of ST131 did not contribute directly to the high prevalence of CTX-M-15 in our settings.

scholarly journals Predicting Ideological Prejudice: A Pre-Registered Replication of Brandt (2017)

2018 ◽  
Author(s):  
Mark John Brandt
Keyword(s):  
Time Series ◽  
Simple Model ◽  
Political Ideology ◽  
Meta Analysis ◽  
Null Model ◽  
National Election ◽  
Target Group ◽  
Archival Data ◽  
Target Groups ◽  
Better Than

Brandt (2017) demonstrated that a simple model using the perceived ideology of a target group can predict the size and direction of the association between political ideology and prejudice. A meta-analysis of four studies showed that this simple ideology only model performs better than a null model and models using the perceived conventionalism, status, and choice of being a member of the target groups. This report describes a preregistered replication which uses data from the American National Election Study’s 2016 Time Series (N = 2616), archival data that was only made available after the study was preregistered. The findings of Brandt (2017) were replicated and the meta-analysis reported in Brandt (2017) is updated with these new data.

scholarly journals High prevalence of trimethoprim-resistance cassettes in class 1 and 2 integrons in Senegalese Shigella spp isolates

2010 ◽  
Vol 4 (04) ◽  
pp. 207-212 ◽  
Author(s):  
Amy Gassama Sow ◽  
Awa Aïdara-Kane ◽  
Olivier Barraud ◽  
Martine Gatet ◽  
François Denis ◽  
...  
Keyword(s):  
Multiple Drug Resistance ◽  
Acquired Resistance ◽  
Multiple Drug ◽  
Antimicrobial Drugs ◽  
Class 1 Integrons ◽  
High Prevalence ◽  
Class 1 ◽  
Shigella Spp ◽  
Clonal Spread ◽  
Established Role

Background: Integrons have a well-established role in the dissemination of resistance among Gram-negative pathogens and are thus a useful marker of antibiotic resistance. Shigellae are noteworthy for their multiple drug resistance, having gradually acquired resistance to most widely use and inexpensive antimicrobial drugs. Methodology: A total of 32 Shigella strains belonging to serotypes flexneri, dysenteriae, and boydii 20, a new Shigella serovar, resistant to at least four antibiotics were analyzed by molecular techniques.Results: Class 1 integrons were the most prevalent (92.8%); class 2 integrons were found in 16 strains (57.1%). Fifty percent of the strains harboured both class 1 and 2 integrons (intI1 and intI2 genes); this combination of integrase genes was most prevalent in S. boydii 20 and S. dysenteriae strains. The class 1 integrons detected contained dfr and aadA cassettes, alone or in combination (dfrA5/dfrA15, or dfrA15-aadA1, dfrA1-aadA2), and an atypical cassette array with an insertion sequence (oxa30-aadA1-IS1). For class 2 integrons, we detected either the same cassettes as those found in Tn7 (dfrA1-sat1-aadA1-orfX) or truncated class 2 integrons without aadA1 or orfX. The tns genes were absent from all class 2 integrons.The distribution of integrons among RAPD profiles and serotypes revealed a clonal spread of integrons into serotypes and a transfer of integrons between different serotypes. Conclusions: The detection of integrons in a new Shigella serovar, in addition with a high integron prevalence among Shigella strains, confirms the propensity of shigellae to acquire and disseminate resistance determinants.

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