Characterization of the bacterial communities of life stages of free living lone star ticks (Amblyomma americanum).

The lone star tick (Amblyomma americanum) is an abundant and aggressive biter of humans, domestic animals, and wildlife in the southeastern-central USA and an important vector of several known and suspected zoonotic bacterial pathogens. However, the biological drivers of bacterial community variation in this tick are still poorly defined. Knowing the community context in which tick-borne bacterial pathogens exist and evolve is required to fully understand the ecology and immunobiology of the ticks and to design effective public health and veterinary interventions. We performed a metagenomic survey of the bacterial communities of questing A. americanum and tested 131 individuals (66 nymphs, 24 males, and 41 females) from five sites in three states. Pyrosequencing was performed with barcoded eubacterial primers targeting variable 16S rRNA gene regions 5-3. The bacterial communities were dominated by Rickettsia (likely R. amblyommii) and an obligate Coxiella symbiont, together accounting for 6.7-100% of sequences per tick. DNAs from Midichloria, Borrelia, Wolbachia, Ehrlichia, Pseudomonas, or unidentified Bacillales, Enterobacteriaceae, or Rhizobiales groups were also detected frequently. Wolbachia and Midichloria significantly co-occurred in Georgia (p<0.00001), but not in other states. The significance of the Midichloria-Wolbachia co-occurrence is unknown. Among ticks collected in Georgia, nymphs differed from adults in both the composition (p = 0.002) and structure (p = 0.002) of their bacterial communities. Adults differed only in their community structure (p = 0.002) with males containing more Rickettsia and females containing more Coxiella. Comparisons among adult ticks collected in New York and North Carolina supported the findings from the Georgia collection despite differences in geography, collection date, and sample handling, implying that the differences detected are consistent attributes. The data also suggest that some members of the bacterial community change during the tick life cycle and that some sex-specific attributes may be detectable in nymphs

Significance of co-infection patterns between selected operational taxonomic units (OTUs).

<p>Only data from the Georgia tick DNA sample collection is shown. The upper triangle represents <i>p</i>-values of positive associations (codetection in the same sample) between OTUs and the lower triangle the <i>p</i>-values of negative associations. Black cells were not evaluated due to low expected co-occurrence (<1) between the OTUs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102130#pone.0102130-Veech1" target="_blank">[49]</a>.</p

Multivariate analysis of the effect of sex and life stage on the relatedness of <i>Amblyomma americanum</i> bacterial communities.

<p>Tick DNAs from the archival collection (n = 27) were older, collected in a different geographical region, and processed using different protocols than tick DNAs from the Georgia collection (n = 104).</p><p>*Corrected for multiple comparisons using Holm’s method; α  = 0.05.</p

Life stage and geographic origin of <i>Amblyomma americanum</i> ticks used in bacterial community analyses.

§<p>Nymphs collected in July 2010; adults in July 2010 and May 2011.</p><p>*Nymphs collected in August 2010; adults in May 2011.</p><p>NT = Not tested.</p

Non-metric multi-dimensional scaling (NMDS) of a Bray-Curtis distance matrix describing Georgian <i>Amblyomma americanum</i> bacterial communities.

<p>Each point symbolizes a single tick’s community (n = 104); some points may overlap completely. Point and ellipse colors indicate life stage; ellipses represent 95% confidence intervals around life stage centroids. Non-overlapping centroids are considered significantly different at α = 0.05. R² values in the upper left corner of plots describe the amount of variation in the data set explained by the groupings. The stress value given is a measure of the disagreement between the rank order in the original data set and that in the NMDS (lower numbers indicate better agreement). Brown numbers indicate the species scores for select OTUs as follows: (1) <i>Coxiella</i>, (2) <i>Rickettsia</i>, (3) <i>Midichloria</i> 1, (4) <i>Borrelia</i>, (5) <i>Ehrlichia</i>, (6) Bacillales 1, (7) <i>Wolbachia</i>, (8) Rhizobiales 1, (9) <i>Rhodobaca</i>, (10) Bacillales 2, (11) <i>Nitriliruptor</i>, (12) Bacillales 3.</p

Non-metric multi-dimensional scaling (NMDS) of a Bray-Curtis distance matrix describing archival <i>Amblyomma americanum</i> bacterial communities.

<p>Each point symbolizes a single tick’s community (n = 27); some points may overlap completely. Point and ellipse colors indicate life stage; ellipses represent 95% confidence intervals around life stage centroids. Non-overlapping centroids are considered significantly different at α = 0.05. R² values in the upper left corner of plots describe the amount of variation in the data set explained by the groupings. The stress value is a measure of the disagreement between the rank order in the original data set and that in the NMDS (lower numbers indicate better agreement). Numbers indicate the species scores for the plot as follows: (1) <i>Coxiella</i>, (2) <i>Rickettsia</i>, (3) <i>Midichloria</i> 1, (4) <i>Borrelia</i>, (5) <i>Francisella</i>, (6) <i>Midichloria</i> 2, (7) <i>Ehrlichia</i>, (8) Enterobacteriaceae, (9) <i>Pseudomonas</i> 1, (10) Burkholderiaceae, (11) Acidobacteria Gp1, (12) <i>Pseudomonas</i> 2, (13) Rhizobiales 2, (14) <i>Bacillus</i>, (15) Acetobacteraceae 1, (16) Acetobacteraceae 2, (17) Bacteria 1, (18) Bacteria 2.</p

Bacterial operational taxonomic unit (OTU) sequence abundance detected in tick samples.

<p>OTUs present in greater than one third of all tick samples were considered broadly distributed. OTUs present at a mean abundance ≥1% of the community (i.e. 10 sequences) were considered locally abundant. Sequence abundance values are slightly offset to reveal overlapping OTUs.</p

Factors associated with supportive care service use among California Alzheimer's disease patients and their caregivers

BACKGROUND: Existing literature on factors associated with supportive care service (SCS) use is limited. A better understanding of these factors could help tailor SCS to the needs of frequent users, as well as facilitate targeted outreach to populations that underutilize available services. OBJECTIVE: To investigate the prevalence of SCS use and to identify factors associated with, and barriers to, service use. METHODS: California Alzheimer's Disease Center patients with AD (n = 220) participated in the study from 2006-2009. Patients and their caregivers completed assessments to determine SCS use. Cognitive, functional, and behavioral status of the patients were also assessed. A two-part hurdle analysis identified 1) factors associated with any service use and 2) service use frequency among users. RESULTS: Forty percent of participants reported using at least one SCS. Patients with more impaired cognition and activities of daily living and more of the following: total number of medications, comorbid medical conditions, and years of education were more likely to use any SCS (p