Update on Pneumocystis carinii f. sp. hominis Typing Based on Nucleotide Sequence Variations in Internal Transcribed Spacer Regions of rRNA Genes

Pneumocystis carinii f. sp. hominis isolates from 207 clinical specimens from nine countries were typed based on nucleotide sequence variations in the internal transcribed spacer regions I and II (ITS1 and ITS2, respectively) of rRNA genes. The number of ITS1 nucleotides has been revised from the previously reported 157 bp to 161 bp. Likewise, the number of ITS2 nucleotides has been changed from 177 to 192 bp. The number of ITS1 sequence types has increased from 2 to 15, and that of ITS2 has increased from 3 to 14. The 15 ITS1 sequence types are designated types A through O, and the 14 ITS2 types are named types a through n. A total of 59 types of P. carinii f. sp. hominis were found in this study.     

A Case-Crossover Analysis of Indoor Heat Exposure on Mortality and Hospitalizations among the Elderly in Houston,Texas

Background: Despite the substantial role indoor exposure has played in heat wave–related mortality, few epidemiological studies have examined the health effects of exposure to indoor heat. As a result, knowledge gaps regarding indoor heat–health thresholds, vulnerability, and adaptive capacity persist.Objective: We evaluated the role of indoor heat exposure on mortality and morbidity among the elderly (≥65 years of age) in Houston, Texas.Methods: Mortality and emergency hospital admission data were obtained through the Texas Department of State Health Services. Summer indoor heat exposure was modeled at the U.S. Census block group (CBG) level using building energy models, outdoor weather data, and building characteristic data. Indoor heat–health associations were examined using time-stratified case-crossover models, controlling for temporal trends and meteorology, and matching on CBG of residence, year, month, and weekday of the adverse health event. Separate models were fitted for three indoor exposure metrics, for individual lag days 0–6, and for 3-d moving averages (lag 0–2). Effect measure modification was explored via stratification on individual- and area-level vulnerability factors.Results: We estimated positive associations between short-term changes in indoor heat exposure and cause-specific mortality and morbidity [e.g., circulatory deaths, odds ratio per 5°C increase=1.16 (95% CI: 1.03, 1.30)]. Associations were generally positive for earlier lag periods and weaker across later lag periods. Stratified analyses suggest stronger associations between indoor heat and emergency hospital admissions among African Americans compared with Whites.Discussion: Findings suggest excess mortality among certain elderly populations in Houston who are likely exposed to high indoor heat. We developed a novel methodology to estimate indoor heat exposure that can be adapted to other U.S. locations. In locations with high air conditioning prevalence, simplified modeling approaches may adequately account for indoor heat exposure in vulnerable neighborhoods. Accounting for indoor heat exposure may improve the estimation of the total impact of heat on health. https://doi.org/10.1289/EHP6340     

A PKR-like eukaryotic initiation factor 2alpha kinase from zebrafish contains Z-DNA binding domains instead of dsRNA binding domains

The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) is induced as part of the IFN response in mammals and acts to shut down protein synthesis by the phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha). In fish, a PKR-like kinase activity has been detected, but the enzyme responsible has eluded characterization. Here, we describe a PKR-like kinase from zebrafish. Phylogenetic analysis shows that the C-terminal kinase domain is more closely related to the kinase domain of PKR than to any of the other three known eIF2alpha kinases. Surprisingly, instead of the two dsRNA binding domains found at the N terminus of PKR, there are two Zalpha domains. Zalpha domains specifically bind dsDNA and RNA in the left-handed Z conformation, often with high affinity. They have been found previously in two other IFN-inducible proteins, the dsRNA editing enzyme, ADAR1, and Z-DNA binding protein 1 (ZBP1), as well as in the poxvirus virulence factor, E3L. This previously undescribed kinase, designated PKZ (protein kinase containing Z-DNA binding domains), is transcribed constitutively at low levels and is highly induced after injection of poly(inosinic)-poly(cytidylic) acid, which simulates viral infection. Binding of Z-DNA by the Zalpha domain of PKZ was demonstrated by circular dichroism. PKZ inhibits translation in transfected cells; site-directed mutagenesis indicates that this inhibition depends on its catalytic activity. Identification of a gene combining Zalpha domains with a PKR-like kinase domain strengthens the hypothesis that the ability to bind left-handed nucleic acid plays a role in the host response to viruses.     

Impact of single-room contact precautions on acquisition and transmission of vancomycin-resistant enterococci on haematological and oncological wards,multicentre cohort-study,Germany, January−December 2016

BackgroundEvidence supporting the effectiveness of single-room contact precautions (SCP) in preventing in-hospital acquisition of vancomycin-resistant enterococci (haVRE) is limited.AimWe assessed the impact of SCP on haVRE and their transmission.MethodsWe conducted a prospective, multicentre cohort study in German haematological/oncological departments during 2016. Two sites performed SCP for VRE patients and two did not (NCP). We defined a 5% haVRE-risk difference as non-inferiority margin, screened patients for VRE, and characterised isolates by whole genome sequencing and core genome MLST (cgMLST). Potential confounders were assessed by competing risk regression analysis.ResultsWe included 1,397 patients at NCP and 1,531 patients at SCP sites. Not performing SCP was associated with a significantly higher proportion of haVRE; 12.2% (170/1,397) patients at NCP and 7.4% (113/1,531) patients at SCP sites (relative risk (RR) 1.74; 95% confidence interval (CI): 1.35–2.23). The difference (4.8%) was below the non-inferiority margin. Competing risk regression analysis indicated a stronger impact of antimicrobial exposure (subdistribution hazard ratio (SHR) 7.46; 95% CI: 4.59–12.12) and underlying disease (SHR for acute leukaemia 2.34; 95% CI: 1.46–3.75) on haVRE than NCP (SHR 1.60; 95% CI: 1.14–2.25). Based on cgMLST and patient movement data, we observed 131 patient-to-patient VRE transmissions at NCP and 85 at SCP sites (RR 1.76; 95% CI: 1.33–2.34).ConclusionsWe show a positive impact of SCP on haVRE in a high-risk population, although the observed difference was below the pre-specified non-inferiority margin. Importantly, other factors including antimicrobial exposure seem to be more influential.     

Atmosphere-sensitive photoluminescence of CoxFe3−xO4 metal oxide nanoparticles

In this work the photoluminescence (PL) of Co_xFe_3−xO₄ spinel oxide nanoparticles under pulsed UV laser irradiation (λ_exc = 270 nm) is investigated for varying Co/Fe ratios (x = 0.4_⋯2.5). A broad emission in the green spectral range is observed, exhibiting two maxima at around 506 nm, which is dominant for Fe-rich nanoparticles (x = 0.4, 0.9), and at around 530 nm, that is more pronounced for Co-rich nanoparticles (x > 1.6). As examinations in different atmospheres show that the observed emission reacts sensitively to the presence of water, it is proposed that the emission is mainly caused by OH groups with terminal or bridging metal–O bonds on the Co_xFe_3−xO₄ surface. Raman spectroscopy supports that the emission maximum at 506 nm corresponds to terminal OH groups bound to metal cations on tetrahedral sites (i.e., Fe³⁺), while the maximum around 530 nm corresponds to terminal OH groups bound to metal cations on octahedral sites (i.e., Co³⁺). Photoinduced dehydroxylation shows that OH groups can be removed on Fe-rich nanoparticles more easily, leading to a conversion process and the formation of new OH groups with different bonds to the surface. As such behavior is not observed for Co_xFe_3−xO₄ with x > 1.6, we conclude that the OH groups are more stable against dehydroxylation on Co-rich nanoparticles. The higher OH stability is expected to lead to a higher catalytic activity of Co-rich cobalt ferrites in the electrochemical generation of oxygen.

Co_xFe_3−xO₄ (0.4 < x < 2.5) nanoparticles show a broad green emission induced by surface OH-groups with a lower stability regarding UV-photoinduced dehydroxylation on Fe-rich (x ≤ 1.6) nanoparticles.     

Imaging of infected total arthroplasty with Tc-99m-labeled antigranulocyte antibody Fab'fragments

OBJECTIVE: The objective of this study was to evaluate the diagnostic accuracy of Tc-99m-labeled antigranulocyte antibody Fab' fragments in infected total arthroplasty. MATERIALS AND METHODS: A total of 38 immunoscintigrams were evaluated retrospectively with 15 to 25 mCi Tc-99m-labeled antigranulocyte antibody-Fab' fragments. The final diagnosis was assessed by articular puncture or intraoperative sampling. RESULTS: In the total hip replacement group the authors found 10 true positives, 7 true negatives, 8 false positives, and 1 false negative; and in the total knee replacement group they found 4 true positives, 8 true negatives, and no false positives or false negatives. They also found a sensitivity of 93%, a specificity of 65%, and a positive predictive accuracy of 63%. There was a negative predictive accuracy of 94%. CONCLUSION: The high negative predictive accuracy in the whole group suggests that the scan can be used to exclude infection in most cases. Negative results with a high clinical suspicion merits further investigation. A positive result will require further correlative imaging, especially for total knee replacement.