Characterizing the Transfer of Bacterial Antibiotic Resistance Genes Across Generations of Swine

Sows and pigs were used to characterize the origin, transfer and persistence of bacterial resistance in swine. Effects of sow’s previous exposure to antibiotics and subsequent use of antibiotics in their pigs on antibiotic resistance of Salmonella enterica Typhimurium, Enterococcus faecalis, and E. coli were determined. Eight pregnant sows were divided into two groups, with four sows receiving oxytetracycline and four sows receiving no antibiotics. Fecal samples were obtained from sows prior to antibiotic exposure, and at 1- week intervals until pigs were weaned. Weaned pigs were challenged with Salmonella Typhimurium containing a nalidixic acid. Pigs from each sow treatment group were divided equally between a subtherapeutic antibiotic treatment regimen or exclusion of antibiotics. Pigs on the antibiotic treatment received apramycin at 150 g/ton of feed, beginning 7 days postweaning and lasting for 14 days, followed by oxytetracycline at 50 g/ton throughout the grow/finish period. Fecal samples were obtained from the pigs while on the sows and at 2, 7, 14, 30, 60, 114 and 115 days postweaning. The Salmonella challenge organism, E. coli and E. faecalis were recovered and tested against both apramycin and oxytetracycline using a minimum inhibitory concentration (MIC) analysis. Data were analyzed using the mixed models procedure of SAS. Polymerase Chain Reaction and transformation techniques were used to characterize genetic resistance elements and determine if the location of such gene sequences. Random apramycinresistant E. coli isolates (n = 110) were chosen from antibiotic treated sows and pigs, non-antibiotic treated sows and pigs and environmental manure to test through PCR, plasmid profiling, and macrorestriction analysis. Treatments affected antibiotic resistance to the greatest extent in E. coli, compared to Salmonella Typhimurium and Enterococcus faecalis. The greatest resistance to apramycin occurred in E. coli isolates from nursing pigs on sows that had earlier exposure to tetracyclines, and from pigs treated with apramycin during the postweaning period. Resistance to oxytetracycline was consistently high throughout the study in isolates from all pigs and sows, including those with no previous exposure to that drug. Genes responsible for apramycin resistance were found in approximately 90% of resistant isolates and their location was determined to be on bacterial plasmids. It was also determined that several different types of E. coli contained the aac(3)-IV gene responsible for apramycin resistance. These results indicate that apramycin and tetracycline resistance in E. coli was affected by previous use of tetracycline in sows (P ≥ 05). Additionally, subsequent use of antibiotics in pigs also affected (P ≤ 05) resistance levels in E. coli, whereas Salmonella Typhimurium and Enterococcus faecalis were not affected by antibiotic use in sows or pigs. Key Words: antibiotic resistance, swine, E. col

Evidence for gene flow differs from observed dispersal patterns in the Humboldt penguin, Spheniscus humboldti

The Humboldt penguin, once common throughout its range, is today listed as Vulnerable by the IUCN. Mark-recapture and telemetry studies indicate that adult Humboldt penguins are sedentary, suggesting strong genetic differentiation between colonies. We developed genotypes for 336 individuals at 12 microsatellite loci sampled at four different localities spanning the entire range of this species. Results show that long-term gene flow has occurred but appears to be affected by geographic distance as pairwise F ST comparisons involving the colony at Punta San Juan (Peru) and the two colonies at Algarrobo (central Chile) and Puñihuil (southern Chile) are significant. Bayesian estimates of recent migration rates indicate substantial dispersal among all colonies. Despite the dramatic decline in numbers, we did not observe a bottleneck in any population. Furthermore, we did not detect a founder effect in the recently discovered colony at Puñihuil. As our indirect estimates signal strong gene flow between populations, we suggest that Humboldt penguin colonies need to be managed as a metapopulation rather than as discrete management unit

Immune Function and Muscle Adaptations to Resistance exercise in Older Adults: Study Protocol for a Randomized Controlled Trial of a Nutritional Supplement

BACKGROUND: Immune function may influence the ability of older adults to maintain or improve muscle mass, strength, and function during aging. Thus, nutritional supplementation that supports the immune system could complement resistance exercise as an intervention for age-associated muscle loss. The current study will determine the relationship between immune function and exercise training outcomes for older adults who consume a nutritional supplement or placebo during resistance training and post-training follow-up. The supplement was chosen due to evidence suggesting its ingredients [arginine (Arg), glutamine (Gln), and β-hydroxy β-methylbutyrate (HMB)] can improve immune function, promote muscle growth, and counteract muscle loss. METHODS/DESIGN: Veterans (age 60 to 80 yrs, N = 50) of the United States military will participate in a randomized double-blind placebo-controlled trial of consumption of a nutritional supplement or placebo during completion of three study objectives: 1) determine if 2 weeks of supplementation improve immune function measured as the response to vaccination and systemic and cellular responses to acute resistance exercise; 2) determine if supplementation during 36 sessions of resistance training boosts gains in muscle size, strength, and function; and 3) determine if continued supplementation for 26 weeks post-training promotes retention of training-induced gains in muscle size, strength, and function. Analyses of the results for these objectives will determine the relationship between immune function and the training outcomes. Participants will undergo nine blood draws and five muscle (vastus lateralis) biopsies so that the effects of the supplement on immune function and the systemic and cellular responses to exercise can be measured. DISCUSSION: Exercise has known effects on immune function. However, the study will attempt to modulate immune function using a nutritional supplement and determine the effects on training outcomes. The study will also examine post-training benefit retention, an important issue for older adults, usually omitted from exercise studies. The study will potentially advance our understanding of the mechanisms of muscle gain and loss in older adults, but more importantly, a nutritional intervention will be evaluated as a complement to exercise for supporting muscle health during aging. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02261961, registration date 10 June 2014, recruitment active

Wii-Fit for Improving Gait and Balance in an Assisted Living Facility: A Pilot Study

Objectives. To determine the effects on balance and gait of a Wii-Fit program compared to a walking program in subjects with mild Alzheimer's dementia (AD). Methods. A prospective randomized (1 : 1) pilot study with two intervention arms was conducted in an assisted living facility with twenty-two mild AD subjects. In both groups the intervention occurred under supervision for 30 minutes daily, five times a week for eight weeks. Repeated measures ANOVA and paired t-tests were used to analyze changes. Results. Both groups showed improvement in Berg Balance Scale (BBS), Tinetti Test (TT) and Timed Up and Go (TUG) over 8 weeks. However, there was no statistically significant difference between the groups over time. Intragroup analysis in the Wii-Fit group showed significant improvement on BBS (P = 0.003), and TT (P = 0.013). The walking group showed a trend towards improvement on BBS (P = 0.06) and TUG (P = 0.07) and significant improvement in TT (P = 0.06). Conclusion. This pilot study demonstrates the safety and efficacy of Wii-Fit in an assisted living facility in subjects with mild AD. Use of Wii-Fit resulted in significant improvements in balance and gait comparable to those in the robust monitored walking program. These results need to be confirmed in a larger, methodologically sound study

Effect of Transmission Reduction by Insecticide-Treated Bednets (ITNs) on Antimalarial Drug Resistance in Western Kenya

Despite the clear public health benefit of insecticide-treated bednets (ITNs), the impact of malaria transmission-reduction by vector control on the spread of drug resistance is not well understood. In the present study, the effect of sustained transmission reduction by ITNs on the prevalence of Plasmodium falciparum gene mutations associated with resistance to the antimalarial drugs sulfadoxine-pyrimethamine (SP) and chloroquine (CQ) in children under the age of five years was investigated during an ITN trial in Asembo area, western Kenya. During the ITN trial, the national first line antimalarial treatment changed from CQ to SP. Smear-positive samples collected from cross sectional surveys prior to ITN introduction (baseline, n = 250) and five years post-ITN intervention (year 5 survey, n = 242) were genotyped for single nucleotide polymorphisms (SNPs) at dhfr-51, 59, 108, 164 and dhps-437, 540 (SP resistance), and pfcrt-76 and pfmdr1-86 (CQ resistance). The association between the drug resistance mutations and epidemiological variables was evaluated. There were significant increases in the prevalence of SP dhps mutations and the dhfr/dhps quintuple mutant, and a significant reduction in the proportion of mixed infections detected at dhfr-51, 59 and dhps-437, 540 SNPs from baseline to the year 5 survey. There was no change in the high prevalence of pfcrt-76 and pfmdr1-86 mutations. Multivariable regression analysis further showed that current antifolate use and year of survey were significantly associated with more SP drug resistance mutations. These results suggest that increased antifolate drug use due to drug policy change likely led to the high prevalence of SP mutations 5 years post-ITN intervention and reduced transmission had no apparent effect on the existing high prevalence of CQ mutations. There is no evidence from the current study that sustained transmission reduction by ITNs reduces the prevalence of genes associated with malaria drug resistance

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

End-Stage Renal Disease in African Americans With Lupus Nephritis Is Associated With APOL1

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE) that exhibits familial aggregation and may progress to end-stage renal disease (ESRD). LN is more prevalent among African Americans than among European Americans. This study was undertaken to investigate the hypothesis that the apolipoprotein L1 gene (APOL1) nephropathy risk alleles G1/G2, common in African Americans and rare in European Americans, contribute to the ethnic disparity in risk