Comparison of the gut microbiota of short-term and long-term medical workers and non-medical controls: a cross-sectional analysis.

OBJECTIVES: The hospital environment has been implicated in the enrichment and exchange of pathogens and antibiotic resistance, but its potential in shaping the symbiotic microbial community of hospital staff is unclear. This study was designed to evaluate the alteration of the gut microbiome in medical workers compared to non-medical controls. METHODS: A prospective cross-sectional cohort study was conducted in the intensive care unit (ICU) and other departments of a centre in north-eastern China. Faecal samples of 175 healthy medical workers-short-term (1-3 months) workers (n = 80) and long-term (>1 year) workers (n = 95)-and 80 healthy non-medical controls were analysed using 16S rRNA amplicon sequencing. The hospital environmental samples (n = 9) were also analysed. RESULTS: The gut microbiomes of medical workers exhibited marked deviations in diversity and alteration in microbial composition and function. Short-term workers showed significantly higher abundances of taxa such as Lactobacillus, Butyrivibrio, Clostridiaceae, Clostridium, Ruminococcus, Dialister, Bifidobacterium, Odoribacter, and Desulfovibrio and lower abundances of Bacteroides and Blautia than the controls. Long-term workers showed higher abundances of taxa such as Dialister, Veillonella, Clostridiaceae, Clostridium, Bilophila, Desulfovibrio, Pseudomonas, and Akkermansia and lower abundances of Bacteroides and Coprococcus than the controls. The medical workers' department (ICU versus non-ICU) and position (resident doctor versus nursing staff) also impacted their gut microbiome. Compared with the non-ICU workers, workers in the ICU showed a significant increase in the abundances of Dialister, Enterobacteriaceae, Phascolarctobacterium, Pseudomonas, Veillonella, and Streptococcus and a marked depletion of Faecalibacterium, Blautia, and Coprococcus. In contrast with the nursing staff, the resident doctors showed a significant increase in Erysipelotrichaceae and Clostridium and a decrease in Bacteroides, Blautia, and Ruminococcus in the gut microbiome. Moreover, we found that the microbiota of hospital environments potentially correlated with the workers' gut microbiota. CONCLUSIONS: Our findings demonstrated structural changes in the gut microbial community of medical workers.

[Influence Factors and Sensitivity of Ozone Formation in Langfang in the Summer].

The diurnal variations in ozone concentrations in the summer were studied using the temperature, wind speed and direction, total cloud cover, and solar radiation intensity data collected in Langfang, China. The ratio of volatile organic compounds to nitrogen oxides (VOCs/NOx) and the EKMA curve were studied to analyze the sensitivity of ozone formation. The results showed that:① The ozone generation rate and ozone concentrations were positively correlated with the solar radiation intensity with Pearson correlation coefficients of 0.61 and 0.48, respectively. Both the ozone generation rate and the solar radiation intensity reached their peak at about 12:00, while the ozone concentration reached its peak at about 16:00, which lagged behind the peak of the solar radiation intensity by 4 h. ② The correlation coefficient between the ozone generation rate and the temperature was 0.44, between the ozone concentration and temperature was 0.68. The ozone generation rate and ozone concentrations were inversely correlated with total cloud cover with correlation coefficients of -0.24 and -0.45, respectively. ③ The ozone concentrations in Langfang were high when the winds were from the west, south, or southeast. ④ The ozone concentrations in Langfang were more sensitive to VOCs than to NOx; thus, they can be reduced efficiently by controlling the VOCs emissions.

[Characteristics of Particulate Matter and Carbonaceous Species in Ambient Air at Different Air Quality Levels].

This study describes the characteristics of particulate matter and carbonaceous species at different air quality levels. The concentrations of PM10, PM2.5, PM1, and carbonaceous species in PM2.5 were monitored on-line in Langfang City on March 1-22, 2016. The PM10, PM2.5, and PM1 concentrations were 204.1 µg·m-3, 107.9 µg·m-3, and 87.8 µg·m-3, respectively. Diurnal variations in particulate matter concentrations showed a bimodal distribution. In general, the mass concentrations of particulate matter and carbonaceous species (OC, EC, SOC, and POC) and the ratios of PM1/PM10 and PM2.5/PM10 were lower on better air quality periods. However, the mass concentration of PM10 was the highest on moderately polluted times. The ratios of PM1/PM10 and PM2.5/PM10 reached minimum values on moderately polluted times.The mass concentration of OC was slightly lower in moderately polluted periods than slightly polluted times; it was significantly lower in moderately polluted periods compared to severely polluted time periods. Hourly concentrations of OC and EC were lower between the hours of 13:00 and 23:00 compared to slightly polluted and severely polluted periods. The proportion of PM2.5 and PM1 decreased in moderately polluted time periods, consistent with the corresponding primary pollutants. Besides, the value of OC/EC was larger than 2.0. The concentrations of SOC and POC estimated using the minimum OC/EC ratio were 12.2 µg·m-3 and 5.0 µg·m-3, respectively.