Characterization of the public transit air microbiome and resistome reveals geographical specificity.

BACKGROUND: The public transit is a built environment with high occupant density across the globe, and identifying factors shaping public transit air microbiomes will help design strategies to minimize the transmission of pathogens. However, the majority of microbiome works dedicated to the public transit air are limited to amplicon sequencing, and our knowledge regarding the functional potentials and the repertoire of resistance genes (i.e. resistome) is limited. Furthermore, current air microbiome investigations on public transit systems are focused on single cities, and a multi-city assessment of the public transit air microbiome will allow a greater understanding of whether and how broad environmental, building, and anthropogenic factors shape the public transit air microbiome in an international scale. Therefore, in this study, the public transit air microbiomes and resistomes of six cities across three continents (Denver, Hong Kong, London, New York City, Oslo, Stockholm) were characterized. RESULTS: City was the sole factor associated with public transit air microbiome differences, with diverse taxa identified as drivers for geography-associated functional potentials, concomitant with geographical differences in species- and strain-level inferred growth profiles. Related bacterial strains differed among cities in genes encoding resistance, transposase, and other functions. Sourcetracking estimated that human skin, soil, and wastewater were major presumptive resistome sources of public transit air, and adjacent public transit surfaces may also be considered presumptive sources. Large proportions of detected resistance genes were co-located with mobile genetic elements including plasmids. Biosynthetic gene clusters and city-unique coding sequences were found in the metagenome-assembled genomes. CONCLUSIONS: Overall, geographical specificity transcends multiple aspects of the public transit air microbiome, and future efforts on a global scale are warranted to increase our understanding of factors shaping the microbiome of this unique built environment.

Efficacy and Stability of Integrating Fungicide and Cultivar Resistance to Manage Fusarium Head Blight and Deoxynivalenol in Wheat.

Integration of host resistance and prothioconazole + tebuconazole fungicide application at anthesis to manage Fusarium head blight (FHB) and deoxynivalenol (DON) in wheat was evaluated using data from over 40 trials in 12 U.S. states. Means of FHB index (index) and DON from up to six resistance class-fungicide management combinations per trial (susceptible treated [S_TR] and untreated [S_UT]; moderately susceptible treated [MS_TR] and untreated [MS_UT]; moderately resistant treated [MR_TR] and untreated [MR_UT]) were used in multivariate meta-analyses, and mean log response ratios across trials were estimated and transformed to estimate mean percent control ( ) due to the management combinations relative to S_UT. All combinations led to a significant reduction in index and DON (P < 0.001). MR_TR was the most effective combination, with a of 76% for index and 71% for DON, followed by MS_TR (71 and 58%, respectively), MR_UT (54 and 51%, respectively), S_TR (53 and 39%, respectively), and MS_UT (43 and 30%, respectively). Calculations based on the principle of treatment independence showed that the combination of fungicide application and resistance was additive in terms of percent control for index and DON. Management combinations were ranked based on percent control relative to S_UT within each trial, and nonparametric analyses were performed to determine management combination stability across environments (trials) using the Kendall coefficient of concordance (W). There was a significant concordance of management combinations for both index and DON (P < 0.001), indicating a nonrandom ranking across environments and relatively low variability in the within-environment ranking of management combinations. MR_TR had the highest mean rank (best control relative to S_UT) and was one of the most stable management combinations across environments, with low rank stability variance (0.99 for index and 0.67 for DON). MS_UT had the lowest mean rank (poorest control) but was also one of the most stable management combinations. Based on Piepho's nonparametric rank-based variance homogeneity U test, there was an interaction of management combination and environment for index (P = 0.011) but not for DON (P = 0.147), indicating that the rank ordering for index depended somewhat on environment. In conclusion, although the magnitude of percent control will likely vary among environments, integrating a single tebuconazole + prothioconazole application at anthesis with cultivar resistance will be a more effective and stable management practice for both index and DON than either approach used alone.

Triazolam use in a university medical center.

The results of a drug-use evaluation (DUE) of triazolam at a university medical center are reported. The DUE was conducted at three institutions in a medical center complex with over 1100 beds. Indicators and thresholds were developed by the DUE subcommittee and approved by each institution's pharmacy and therapeutics committee. The medical charts of patients for whom triazolam was prescribed during January through March 1991 were reviewed. The relationship between the occurrence of adverse drug reactions (ADRs) and triazolam use was evaluated with the Naranjo ADR probability scale. Of 192 patients whose medical charts were reviewed, 123 (64%) were prescribed 0.125-mg doses. Patients who were > 70 years of age were more likely than younger patients to be prescribed this low dose (84% versus 60%). Fifty-four patients (28%) received no doses; a median of two doses (range, 1-46) were received by the remaining 138 patients. Twelve (9%) of those 138 patients experienced ADRs considered to be possibly (n = 10) or probably (n = 2) related to triazolam. Possible triazolam-associated reactions consisted of confusion (four cases), weakness and lethargy (four), and dizziness (two); probable triazolam-associated ADRs were confusion (one case) and next-day somnolence (one). Factors potentially contributing to ADRs included the presence of concomitant diseases or medications, the total number of doses received, and patient age. Of 138 hospitalized patients who had been given one or more doses of triazolam, 12 had had possible or probable triazolam-associated ADRs. The use of low doses and short-term therapy, particularly in elderly patients, may reduce the likelihood of ADRs.

Effect of myocardial ischemia on uridine incorporation and histone acetylation.

The influence of transient myocardial ischemia on recovery uridine incorporation into RNA and histone acetylation was investigated in an isolated perfused rat heart. Hemodynamically, hearts recovered from 15 min of ischemic arrest and were stable for at least 60 min of perfusion. Uridine incorporation was reduced (P less than 0.05) in ischemic hearts by 24 and 26% after 30 and 60 min of recovery perfusion. The incorporation of uridine into RNA from purified myocytes was decreased by 50% in the ischemic muscle cells. The covalent acetylation of total nucleohistones was diminished by 37%. Histone fractionation by urea polyacrylamide gel electrophoresis clearly indicated that histones H3 and H4 preferentially incorporated less acetate during ischemic recovery. However, histone acetylation for proteins H2A + H2B was not effected. These data suggest that a brief period of ischemia disrupts nucleotide incorporation during the recovery phase, with marked decrease associated with the muscle cell. The similar change in histone acetylation indicates a possible link between nucleoproteins and chromatin function during ischemic insult to the heart.

Delayed hypersensitivity to myxoviruses and myxovirus vaccines in the guinea pig.

Influenza, mumps and measles viruses were examined for their ability to induce in guinea pigs homologous and cross-reactive delayed hypersensitivity. A majority of the animals skin tested with homologous and a portion of the animals skin tested with heterologous viruses and vaccines developed positive reactions. Findings with the heterologous preparations suggest that the observed cross-reactive hypersensitivity might be due to shared antigens of viral or substrate origin in the influenza, mumps and measles preparations. The present findings in guinea pigs suggest that the adverse effects, attributed in whole or in part to induced hypersensitivity, observed in man following injection of killed influenza, mumps and measles vaccines could be due to cross-reactive delayed hypersensitivity resulting from the use of these preparations.

Guidelines for defining and disposing of medical waste.

Considerations of ecology, public health hazards, and rising health costs have been critically reevaluated in the matter of appropriate medical waste disposal at nursing homes and hospitals. The Maryland Department of Health has intermittently received reports from the public of human tissues, bandages, and other inappropriate, unaesthetic materials visible in landfill areas. The Department has experienced increasing concern for communicable disease transmission, e.g. hepatitis, to landfill waste handlers and to the general public. Incineration had been considered as an alternative to landfilling of medical wastes, but fear of increasing hospital costs dampened initial enthusiasm for this possibility, particularly when coupled with fears of air pollution by smoke and noxious fumes generated by incineration. Other problems requiring resolution were conflicting definitions of medical waste and disposal requirements by federal, state, and local regulatory bodies. On-site incineration of all waste generated at hospitals is proposed as an economical and ecologically feasible solution to this public health problem in Maryland.

Some factors affecting the expression of Epstein-Barr virus-associated membrane antigens.

The effect of two factors, L-arginine concentration and phytohemagglutinin (PHA) stimulation, on the expression of Epstein-Barr virus (EBV)-associated membrane antigens (MA) was evaluated. An EBV-producer cell line, AV-1, was cultivated in Eagle's basal medium with Earle's salts, supplemented with various L-arginine concentrations ranging from 0.0 to 20.0 mM. In most of the L-arginine concentrations, the number of cells expressing MA decreased within the first 24 hours. This decrease was followed by a marked increase in MA-positive cells at 48 hours and a slight decrease between 48 and 72 hours. Statistical evaluation, however, revealed no significant differences in the level of MA expression among cells exposed to the various L-arginine concentrations. These findings were discussed in relation to the cell cycle dependence of L-arginine-deficient media as a virus-activating agent. AV-1 cell cultures were treated with PHA and observed at 24-hour intervals for 72 hours. Within the first 24 hours, the percentage of cells showing MA was markedly increased. This was followed by a rapid decline in percentage of MA-positive cells within the next 24 hours. Treatment of an EBV-nonproducer cell line, NC37, with PHA resulted in the production of MA in approximately 11% of the cells within the first 24 hours. The number of MA-positive cells gradually declined over the next 48 hours. No viral capsid antigens were detected in these cells. The data suggested either complete or partial activation of the latent EBV genome by PHA.

The effect of mycoplasmas on replication and plaquing ability of Herpes simplex virus.

M. arginini, an arginine utilizer, can decrease the yield of Herpes simplex virus, type 1 grown in Vero cells. M. arginini can also cause a reduction in number and size of plaques produced by HSV. The reduction in titer and plaque size produced in M. arginini-infected cells can be reversed by supplementing medium with additional arginine. A. laidlawii, a nonarginine utilizing mycoplasma, had no effect on the growth of HSV.

Spectral emission signatures of ambient temperature objects.

This report describes the preliminary work to collect the ir spectral emission signatures of ambient temperature objects using a Fourier transform spectrometer operating in the 8-13-microm region of the electromagnetic spectrum. Details of the construction of a sample container are presented along with a description of the spectrometer, the controlling computer, and the data collection techniques and procedures. A system test, which is actually the ratio of two blackbodies at different temperatures, indicates that these procedures are valid. The emissivities of Krylon 1602 ultraflat black paint, crushed fused quartz, and three types of cotton are presented.

Control of interferon, migration inhibition factor, and expression of virus capsid antigens in Burkitt's lymphoma-derived cell lines: role of L-arginine.

The effects of an arginine-utilizing mycoplasma, Mycoplasma arginini, and of varying levels of arginine in the growth media of the Epstein-Barr virus (EBV)-containing EB1 and EB3 cell lines, and the EBV-free RPMI 1788 cell line, were studied. l-Arginine, at a concentration of 0.1 mM in the growth medium, led to a reduction of the EBV capsid antigen content of the EB1 and EB3 cells lines as determined by indirect immunofluorescence, and M. arginini infection enhanced this reduction. The synthesis of two immune products, interferon and macrophage migration inhibition factor, was enhanced by growing the cell lines in medium containing arginine at a concentration of 0.1 mM, but the RPMI 1788 cell line produced much less of both products than EB1 or EB3 under these conditions. Infection of the cell lines with M. arginini reduced the amount of interferon produced and completely inhibited macrophage migration inhibition factor synthesis. The addition of arginine to a final concentration of 0.6 mM in the growth medium caused a dual effect: the EB1 and EB3 cell lines maintained the original level of EBV capsid antigens, even when infected with M. arginini; immune product synthesis was greatly reduced or completely inhibited by the addition of arginine, and M. arginini infection caused no further reduction of immune product synthesis.