Severe skin and soft tissue pythiosis acquired in a hot spring in the southwestern United States, a case report and review of North American cases.

BACKGROUND: Human pythiosis, caused primarily by the aquatic oomycete, Pythium insidiosum, is an emerging but uncommon infection in North America. The infection is frequently life-threatening and is often initially unrecognized due to its rarity and similar presentation to certain fungal infections. METHODS: We report a case of skin and soft tissue pythiosis in a patient without significant underlying comorbidities acquired in a New Mexico hot spring and review its successful treatment. We also review all reported pythiosis cases in North America. RESULTS: Eleven confirmed cases of human pythiosis acquired in North America were identified. The majority of cases occurred in children (64%), ten of eleven cases were acquired in the southern U.S., Mexico, Central America or the Caribbean and four of the eleven individuals succumbed to the infection. CONCLUSIONS: With recognition and aggressive surgical and medical treatment good clinical outcomes can be achieved when treating human pythiosis.

Provision of refugia and seeding with native bivalves can enhance biodiversity on vertical seawalls.

Recent studies have suggested that increasing habitat complexity of artificial seawalls by modifying surface heterogeneity could enhance exploitable habitat and therefore species richness and abundance. We tested the effects of adding complex tiles (with crevices/ledges) of different heterogeneity (i.e., flat tiles resembling the seawall vs. tiles with crevices of 2.5 cm or 5.0 cm depth) and seeding with native rock oysters, Saccostrea cuccullata (unseeded vs. seeded) on species richness and abundances of intertidal marine organisms on two vertical seawalls in Hong Kong. Tiles were affixed to the mid-intertidal zone of the seawalls for 12 months. The results showed that the tiles with crevices had greater species richness and cover of sessile epifauna than flat tiles. Seeding tiles with S. cuccullata also facilitated natural recruitment of the same species. Our results support the hypothesis that using eco-engineering to increase habitat complexity can enhance the biodiversity of intertidal marine organisms on seawalls.

Topic choice contributes to the lower rate of NIH awards to African-American/black scientists.

Despite efforts to promote diversity in the biomedical workforce, there remains a lower rate of funding of National Institutes of Health R01 applications submitted by African-American/black (AA/B) scientists relative to white scientists. To identify underlying causes of this funding gap, we analyzed six stages of the application process from 2011 to 2015 and found that disparate outcomes arise at three of the six: decision to discuss, impact score assignment, and a previously unstudied stage, topic choice. Notably, AA/B applicants tend to propose research on topics with lower award rates. These topics include research at the community and population level, as opposed to more fundamental and mechanistic investigations; the latter tend to have higher award rates. Topic choice alone accounts for over 20% of the funding gap after controlling for multiple variables, including the applicant's prior achievements. Our findings can be used to inform interventions designed to close the funding gap.

Short-term tissue decomposition alters stable isotope values and C:N ratio, but does not change relationships between lipid content, C:N ratio, and Δδ13C in marine animals.

Measures (e.g. δ15N, δ13C, %C, %N and C:N) derived from animal tissues are commonly used to estimate diets and trophic interactions. Since tissue samples are often exposed to air or kept chilled in ice over a short-term during sample preparation, they may degrade. Herein, we hypothesize that tissue decomposition will cause changes in these measures. In this study, we kept marine fish, crustacean and mollusc tissues in air or ice over 120 h (5 days). We found that tissue decomposition in air enriched δ15N (range 0.6‰ to 1.3‰) and δ13C (0.2‰ to 0.4‰), decreased %N (0.47 to 3.43 percentage points from staring values of ~13%) and %C (4.53 to 8.29 percentage points from starting values of ~43%), and subsequently increased C:N ratio (0.14 to 0.75). In air, while such changes to δ13C were relatively minor and therefore likely tolerable, changes in δ15N, %N, %C and C:N ratio should be interpreted with caution. Ice effectively reduced the extent to which decomposition enriched δ15N (≤ 0.4‰) and δ13C (≤ 0.2‰), and eliminated decomposition in C:N ratio, %N and %C. In our second experiment, for fish tissues in either air or ice over 120 h, we observed no effects of decomposition on relationships between lipid content, C:N ratio, and Δδ13C (change in δ13C after lipid removal), which are employed to correct δ13C for samples containing lipid. We also confirmed that lipid in tissues caused large errors when estimating δ13C (mean ± standard error = -1.8‰ ± 0.1‰, range -0.6‰ to -3.8‰), and showed both lipid extraction and mathematical correction performed equally well to correct for lipids when estimating δ13C. We, therefore, recommend that specimens of marine animals should be kept in ice during sample preparation for a short-term, as it is an effective means for minimizing changes of the stable isotope measures in their tissue.

Brief Report: Prevalence of Posttreatment Controller Phenotype Is Rare in HIV-Infected Persons After Stopping Antiretroviral Therapy.

BACKGROUND: Posttreatment control of HIV infection is a rare phenomenon primarily described among those initiating treatment with antiretroviral therapy (ART) during early/acute HIV infection. METHODS: We examined a large, well-characterized cohort of HIV-infected Department of Defense beneficiaries for the presence of posttreatment controllers (PTCs) whom we defined as individuals with sustained viral suppression for ≥6 months after discontinuation of ART. We defined those who became viremic within 6 months of discontinuing ART as rapid viremics (RVs) and compared demographic and clinical characteristics, CD4 counts, and viral loads prior, during, and after ART discontinuation between the 2 groups. RESULTS: From a cohort of 6070 patients, we identified 95 who had been treated with ART for 2 years or more who subsequently discontinued ART and had viral load assessments available after discontinuation. Four (4.2%) of these 95 met our definition of PTC. The duration of viral suppression off of ART ranged from 267 to 1058 days with 1 of the 4 restarting ART without having redeveloped a significant viremia. All 4 patients initiated ART during chronic HIV infection. Demographic and clinical characteristics of PTCs were similar to RVs. CONCLUSIONS: While posttreatment control has predominantly been described among individuals who initiated ART in early/acute HIV infection, we identified 4 PTCs who started ART during chronic infection suggesting that posttreatment control also occurs among such patients. The rarity of PTCs identified in our cohort is consistent with reports from previous studies.

Clostridium sphenoides Chronic Osteomyelitis Diagnosed Via Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry, Conflicting With 16S rRNA Sequencing but Confirmed by Whole Genome Sequencing.

We report a case of successful treatment of chronic osteomyelitis (emanating from contaminated soil exposure) caused by Clostridium sphenoides, an organism infrequently identified as a cause of human infection and more saliently osteomyelitis (only 1 reported case in the literature). Additional impetus for reporting this case resides in the insights gained regarding pathogen identification exploiting sophisticated molecular platforms coupled to traditional microbial culture-based methods. The fastidious nature of cultivating anaerobic organisms required initial attempts at 16S rRNA sequencing to identify a Clostridium species (Clostridium celerecrescens). However, on exploiting matrix-assisted laser desorption ionization time of flight (MALDI TOF) technology, C. sphenoides was identified, and confirmed on whole genome sequencing. The discrepancies noted in the varying platforms require vigilance to seek complementary testing for conflicting results. Although highly accurate, the MALDI TOF and 16S rRNA sequencing platforms are not immune to false identification particularly in differentiating closely related organisms. More germane, whole genome sequencing should be entertained when conflicting results are obtained from MALDI TOF and 16S rRNA sequencing. Precise species and/or strain level identification can be clinically relevant as antimicrobial sensitivity profiles may be discrepant between closely related species influencing clinical outcomes. Thus, it is incumbent on us to strive to acquire the correct species characterization when resources allow to dictate optimal treatment.

Chemical dispersants can suppress the activity of natural oil-degrading microorganisms.

During the Deepwater Horizon oil well blowout in the Gulf of Mexico, the application of 7 million liters of chemical dispersants aimed to stimulate microbial crude oil degradation by increasing the bioavailability of oil compounds. However, the effects of dispersants on oil biodegradation rates are debated. In laboratory experiments, we simulated environmental conditions comparable to the hydrocarbon-rich, 1,100 m deep plume that formed during the Deepwater Horizon discharge. The presence of dispersant significantly altered the microbial community composition through selection for potential dispersant-degrading Colwellia, which also bloomed in situ in Gulf deep waters during the discharge. In contrast, oil addition to deepwater samples in the absence of dispersant stimulated growth of natural hydrocarbon-degrading Marinobacter. In these deepwater microcosm experiments, dispersants did not enhance heterotrophic microbial activity or hydrocarbon oxidation rates. An experiment with surface seawater from an anthropogenically derived oil slick corroborated the deepwater microcosm results as inhibition of hydrocarbon turnover was observed in the presence of dispersants, suggesting that the microcosm findings are broadly applicable across marine habitats. Extrapolating this comprehensive dataset to real world scenarios questions whether dispersants stimulate microbial oil degradation in deep ocean waters and instead highlights that dispersants can exert a negative effect on microbial hydrocarbon degradation rates.

Application of nitrogen and carbon stable isotopes (δ(15)N and δ(13)C) to quantify food chain length and trophic structure.

Increasingly, stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR) using δ(15)N, and carbon range (CR) using δ(13)C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ(15)N or δ(13)C from source to consumer) between trophic levels and among food chains. δ(15)N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰), and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ(13)C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ(13)C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority of ecological systems.

Biventricular Takotsubo cardiomyopathy in Graves hyperthyroidism.

Graves hyperthyroidism is commonly seen in clinical practice and Takotsubo stress cardiomyopathy is an increasingly recognized cardiac complication of physical or emotional stress. We report the rare case of a patient with Graves hyperthyroidism that was complicated by severe biventricular takotsubo cardiomyopathy, which was demonstrated on heart catheterization. After appropriate pharmacologic treatment of her hyperthyroidism, she had complete resolution of her cardiomyopathy.