Streptococcus pneumoniae is an opportunistic pathogen that causes substantial illness and death among children worldwide. The genetic backgrounds of pneumococci that cause infection versus ...asymptomatic carriage vary substantially. To determine the evolutionary mechanisms of opportunistic pathogenicity, we conducted a genomic surveillance study in China. We collected 783 S. pneumoniae isolates from infected and asymptomatic children. By using a 2-stage genomewide association study process, we compared genomic differences between infection and carriage isolates to address genomic variation associated with pathogenicity. We identified 8 consensus k-mers associated with adherence, antimicrobial resistance, and immune modulation, which were unevenly distributed in the infection isolates. Classification accuracy of the best k-mer predictor for S. pneumoniae infection was good, giving a simple target for predicting pathogenic isolates. Our findings suggest that S. pneumoniae pathogenicity is complex and multifactorial, and we provide genetic evidence for precise targeted interventions.
Epidemiological studies have found that increased risk of preterm birth (PTB) is associated with higher prenatal exposure to PM10 and PM2.5, but few studies have been conducted to assess the impacts ...of extremely fine particulate matter (PM1) which may have more toxic effects than other types of ambient particulate air pollution (PM). Several studies have separately investigated the associations between DNA methylation and PTB risk and PM. Maternal LINE-1 methylation level negatively correlated with prenatal exposure to PM and risk of PTB. A comprehensive picture is lacking regarding the associations between prenatal exposure to PM, LINE-1 methylation, and risk of PTB.
This study aimed to estimate the effects of exposure to ambient PM (PM10, PM2.5, and PM1) of different sizes during pregnancy on risk of PTB, identify susceptible exposure windows, and illustrate the roles of LINE-1 methylation in the associations between PM and PTB risk.
The Birth Cohort Study on Prenatal Environments and Offspring Health (PEOH) has been ongoing since 2016 in Guangzhou, China. A total of 4928 pregnant women were recruited during early pregnancy, and 4278 (86.8%) were successfully followed-up. Each individual weekly exposure to PM10 and PM2.5 from 3 months before pregnancy to childbirth was assessed using a spatiotemporal land use regression model, and the weekly PM1 exposure was estimated by employing a generalized additive model. Maternal and cord blood LINE-1 methylation levels (%5mC) were tested using bisulfite-PCR pyrosequencing. A distributed lag nonlinear model incorporated with a Cox proportional hazard model was applied to assess the effect of weekly-specific maternal PM exposure on PTB risk, and a multiple-linear regression model was employed to investigate the associations between PM exposure and LINE-1 methylation levels of maternal and cord bloods. We also assessed the associations between LINE-1 methylation levels and PTB risk by using a logistic regression model.
The risk of PTB was positively associated with PM2.5 and PM1 concentrations during the 12th to 20th gestational weeks, and the strongest association was in the fourth quartile (Q4) versus the first quartile (Q1) and observed during the 16th gestational week (PM2.5: harzard ratio HR = 1.18, 95%CI: 1.04–1.35, IQR = 11.94 μg/m3. PM1: HR = 1.20, 95%CI: 1.03–1.39, IQR = 11.36 μg/m3). We observed significantly negative associations of PM10(β = −0.51%5mC per 10 μg/m3, P = 0.014), PM2.5 (β = −0.66%5mC per 10 μg/m3, P = 0.032) and PM1 (β = −0.67%5mC per 10 μg/m3, P = 0.032) concentrations with cord blood LINE-1 methylation levels, and a negative association between PM1 concentration and maternal LINE-1 methylation level (β = −0.86%5mC per 10 μg/m3, P = 0.034).
Higher prenatal exposure to PM1 and PM2.5 during the 12th to 20th gestational weeks was associated with increased risk of PTB. Maternal and fetal LINE-1 methylation alternation might be an underlying mechanism of PM that increasing the risk of PTB.
•Preterm birth (PTB) risk was positively associated with prenatal exposure to PM2.5 and PM1, and a slightly greater effect was found for PM1 compared with PM2.5.•Gestational weeks 12 to 20 might be the critical window with the peak effect in the 16th week.•Fetal LINE-1 methylation was simultaneously associated with prenatal exposure to ambient particulate air pollution (PM) and PTB risk, indicating that LINE-1 methylation alternation might be an underlying mechanism of PM increasing PTB risk. However, the roles of maternal LINE-1 methylation may differ compared with their infants.
In the present work, we mainly focus on a new established fractional-order predator-prey system concerning both types of time delays. Exploiting an advisable change of variable, we set up an ...isovalent fractional-order predator-prey model concerning a single delay. Taking advantage of the stability criterion and bifurcation theory of fractional-order dynamical system and regarding time delay as bifurcation parameter, we establish a new delay-independent stability and bifurcation criterion for the involved fractional-order predator-prey system. The numerical simulation figures and bifurcation plots successfully support the correctness of the established key conclusions.
Background Multidrug-resistant Pseudomonas aeruginosa (MDRPA) is one of the most common agents among health care–associated infections. There is a lack of data on the clinical features of MDRPA from ...Southern China. Methods A case-control surveillance study of P aeruginosa was conducted based on surveillance from July 2008-December 2012, in 5 hospitals of Guangzhou, China. Data were analyzed by univariate analysis and multivariate logistic regression using Stata 13 (StataCorp, College Station, TX). Results Of the 348 P aeruginosa strains, the prevalence of MDRPA was 54%, and it has increased over time. Isolates of P aeruginosa showed increased resistance to most antimicrobials during this time period. Independent risk factors were tracheal intubation insertion (odds ratio OR, 2.21; 95% confidence interval CI, 1.16-4.23; P = .02) and use of carbapenem (odds ratio OR, 3.36; 95% confidence interval CI, 1.75-6.47; P < .01). The distribution of MDRPA infections was uneven among the 5 hospitals ( P = .01). Being infected with MDRPA strains resulted in longer duration of hospitalization (39 vs 24 days) and higher mortality (49% vs 20%). Conclusion The infections of MDRPA were severe issues. More stringent measures should be applied for those with independent predictors of MDRPA infections because they may induce adverse clinical outcomes.
The use of Ge as framework atom to direct the formation of double‐four‐ring (d4r) unit is an effective way to prepare zeolite with extra‐large pores, which however also brings about serious problems ...with regard to production cost and structure stability for their practical application. A new solvent‐free thermal synthesis strategy is presented here for facile preparation and molecular‐level mechanism study of extra‐large‐pore aluminophosphate zeotype DNL‐1 with ‐CLO structure. For the first time, the formation of intermediate d4r in the induction period was successfully confirmed, and was correlated with the synthesis condition of low water content and quaternary ammonium template with suitable alkyl chain length. The self‐assembly pathway via d4r to form lta, afterwards clo and super cages was further revealed. This work shed light on the rational synthesis of Ge‐free extra‐large‐pore zeotypes based on d4r route.
A simple solvent‐free thermal synthesis method was developed to prepare extra‐large‐pore aluminophosphate zeotype DNL‐1, unravelling its crystallization process via self‐assembly of d4r unit, an intermediate formed at synthesis conditions of low water content in presence of a template structure with alkyl chains of proper length. This new synthesis strategy is suitable for rational preparation of d4r‐containing extra‐large‐pore zeolitic materials in the absence of Ge.
Use of antimicrobials in industrial food animal production is associated with the presence of multidrug-resistant Staphylococcus aureus among animals and humans. The livestock-associated (LA) ...methicillin-resistant S. aureus (MRSA) clonal complex 9 (CC9) is associated with animals and related workers in Asia. This study aimed to explore the genotypic and phenotypic markers of LA-MRSA CC9 in humans. We conducted a cross-sectional study of livestock workers and controls in Guangdong, China. The study participants responded to a questionnaire and provided a nasal swab for S. aureus analysis. The resulting isolates were assessed for antibiotic susceptibility, multilocus sequence type, and immune evasion cluster (IEC) genes. Livestock workers had significantly higher rates of S. aureus CC9 (odds ratio OR = 30.98; 95% confidence interval CI, 4.06 to 236.39) and tetracycline-resistant S. aureus (OR = 3.26; 95% CI, 2.12 to 5.00) carriage than controls. All 19 S. aureus CC9 isolates from livestock workers were MRSA isolates and also exhibited the characteristics of resistance to several classes of antibiotics and absence of the IEC genes. Notably, the interaction analyses indicated phenotype-phenotype (OR = 525.7; 95% CI, 60.0 to 4,602.1) and gene-environment (OR = 232.3; 95% CI, 28.7 to 1,876.7) interactions associated with increased risk for livestock-associated S. aureus CC9 carriage. These findings suggest that livestock-associated S. aureus and MRSA (CC9, IEC negative, and tetracycline resistant) in humans are associated with occupational livestock contact, raising questions about the potential for occupational exposure to opportunistic S. aureus
This study adds to existing knowledge by giving insight into the genotypic and phenotypic markers of LA-MRSA. Our findings suggest that livestock-associated S. aureus and MRSA (CC9, IEC negative, and tetracycline resistant) in humans are associated with occupational livestock contact. Future studies should direct more attention to exploring the exact transmission routes and establishing measures to prevent the spread of LA-MRSA.
is a common infectious bacterium that poses a threat to human health. Nevertheless, there are limited data on the population structure, genetic diversity, and pathogenicity of
, especially among men ...who have sex with men (MSM). The present study aimed to clarify the sequence types (STs), clonal complexes (CCs), resistance genes, and virulence factors of popular strains. Multilocus sequence typing was used to describe the population structure of
. The Virulence Factor Database and Comprehensive Antibiotic Resistance Database were used to assess the virulence and resistance profiles. In this study, next-generation sequencing was performed on nasal swabs specimens collected in an HIV Voluntary Counseling Testing outpatient department in Guangzhou, China, from April to August 2019. The identification results showed that a total of 258
isolates were collected from 911 participants. We found that the isolates were most resistant to furantoin (89.53%, 231/258) and ampicillin (89.15%, 230/258), followed by imipenem (24.81%, 64/258) and cefotaxime (18.22%, 47/258). The most common STs in carbapenem-resistant
were ST4, ST93, and ST14. The population has at least 14 CCs, including several novel ones identified in this study (CC11-CC16). The main mechanism of drug resistance genes was antibiotic efflux. Based on the presence of the iron carrier production genes
and
, we identified two clusters according to virulence profiles. In cluster A, CC3 and CC4 carry the
operator encoding the toxin. Increased monitoring is needed for the three main ST type strains carried by MSM. The main clone group CC4 has a large number of toxin genes, and it spreads among MSM. Caution is needed to prevent further spread of this clone group in this population. In sum, our results may provide a foundation for the development of new therapeutic and surveillance strategies for treating MSM.
While increasing evidence suggested that PM2.5 is the most harmful fraction of the particle pollutants, the health effects of coarse particles (PM10–2.5) have been inconclusive, especially on ...cerebrovascular diseases, we thus evaluated the effects of PM10, PM2.5, and PM10–2.5 on stroke mortality in six Chinese subtropical cities using generalized additive models. We also conducted random-effects meta-analyses to estimate the overall effects across the six cities. We found that PM10, PM2.5, and PM10-2.5 were significantly associated with stroke mortality. Each 10 μg/m3 increase of PM10, PM2.5 and PM10-2.5 (lag03) was associated with an increase of 1.88% (95% CI: 1.37%, 2.39%), 3.07% (95% CI: 2.35%, 3.79%), and 5.72% (95% CI: 3.82%, 7.65%) in overall stroke mortality. Using the World Health Organization's guideline as reference concentration, we estimated that 3.21% (95% CI: 1.65%, 3.01%) of stroke mortality (corresponding to 1743 stroke mortalities, 95% CI: 896, 1633) were attributed to PM10, 5.57% (95% CI: 0.50%, 1.23%) stroke mortality (3019, 95% CI: 2286, 3777) were attributed to PM2.5, and 2.02% (95% CI: 1.85%, 3.08%) of stroke mortality (1097, 95% CI: 1005, 1673) could be attributed to PM10-2.5. Our analysis indicates that both PM2.5 and PM10-2.5 are important risk factors of stroke mortality and should be considered in the prevention and control of stroke in the study area.
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•We estimated the association between coarse PM pollution and stroke mortality.•Both fine and coarse particular are associated with stroke mortality.•The effect of PM10-2.5 on stroke is higher than PM2.5.
We aim to assess the similarities of proportional, phenotypic, and molecular characteristics between the school environment and schoolchildren on methicillin-sensitive S. aureus (MSSA) isolates.
A ...cross-sectional study was conducted between March 2016 and August 2016 in eight elementary schools in Guangzhou, China. Nasal swabs from students and environmental swabs from school environments were collected. Univariate and multivariate logistic regression analyses under a multistage stratified cluster cross-sectional survey design were performed to access the prevalence relationship and influencing factors, respectively. Phenotypic and molecular characterizations of MSSA isolates were conducted using the Kirby-Bauer disk diffusion method and polymerase chain reaction assays, respectively.
In total, 1705 schoolchildren and 1240 environmental samples from 40 classes in eight elementary schools obtained between March and August 2016 were include in this study. The rates of MSSA prevalence among schoolchildren and the environment were 11.44% (195/1705) and 4.60% (57/1240), respectively. The odds ratios and 95% confidence intervals (CIs) on the prevalence of MSSA isolates were 1.11 (95% CI, 1.05-1.29; P = 0.010) and 1.04 (95% CI, 1.01-1.07; P = 0.003) for the school or class environment and students, respectively. Similar phenotypic and molecular characteristics were identified between schoolchildren and the environment. A cause and effect relationship could not be established because the study design was cross-sectional.
Because of the cross-sectional design, we can reveal the association between school environment and schoolchildren on MSSA, but it is not a cause and effect relationship.
We aim to assess the correlation of multidrug-resistant
(MDR
) carriage between mothers and their newborn infants.
We conducted a prospective cohort study of mothers and their newborn infants in two ...hospitals in Shenzhen, China, from August to November 2015. We collected demographic and clinical information from mothers and newborn infants by face-to-face questionnaires and medical datasets. Serial swabs were collected from mothers and their newborn infants for further experiments. Maternal-infant correlation was assessed using the Poisson regression model.
The prevalence of MDR
vaginal carriage in mothers was 4.7% (86/1834). The incidence of MDR
carriage in newborn infants was 1.3% (23/1834). The adjusted relative risk and 95% confidence interval of maternal-infant MDR
carriage was 7.63 (2.99-19.49). Six MDR
maternal-infant pairs were concordant. The phenotypic and molecular characteristics of MDR
isolates were similar between mothers and their newborn infants.
MDR
vaginal carriage in mothers was associated with an increased risk for MDR
carriage in their newborn infants.
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