The effect of cadmium exposure on diversity of intestinal microbial community of Rana chensinensis tadpoles.

Cadmium is a natural and widely distributed toxicant, and can be commonly found in environment. Intestinal microbiota plays a very important role in maintaining its host's health. The effects of cadmium on the intestinal microbiota composition and stability of amphibians are little known. We exposed Rana chensinensis (R. chensinensis) embryos to different concentrations of cadmium (0, 112 and 448 µg Cd L-1) until they reached Gosner stage 38, and analyzed their microbial communities using 16S rRNA amplicon sequencing. By measures of both alpha and beta diversity, intestinal microbial communities were significantly differentiated in 448 µg Cd L-1 exposure groups. Cadmium exposure significantly altered the intestinal microflora diversity and composition of R. chensinensis. At the phylum level, it is worth noting that Fusobacteria and Spirochaetae were not detected in 448 µg Cd L-1 exposure groups. Firmicutes rapidly decreased in 448 µg Cd L-1 exposure group. At the genus level, Succinispira (Firmicutes), Desulfovibrio (Proteobacteria) and Fusobacterium (Fusobacteria) vanished in 448 µg Cd L-1 exposure groups. Our results demonstrate that cadmium exposure changed the composition and decreased the community diversity of intestinal microbiota of R. chensinensis tadpoles. Our study may provide a new framework based on intestinal microbiota to evaluate the response of amphibians to environmental chemicals pollution.

Meningitis and bacteremia caused by Haemophilus influenzae Type e in an immunocompetent child.

Haemophilus influenzae infection is a well-known cause of serious invasive disease in adults and children. But incidence of the common serotypes are type b, f and a. There is very little information available on invasive disease of Haemophilus influenzae type e (Hie) in China, especially in children. We report a case of an immunocompetent child who was clinically diagnosed with bacterial meningitis with bacteremia caused by Hie. The literature on infection especially meningitis caused by Hie is reviewed.

Molecular characterization of pathogenic group B streptococcus from a tertiary hospital in Shanxi, China: High incidence of sequence type 10 strains in infants/pregnant women.

BACKGROUND: Group B streptococcus (GBS) is a leading cause of serious infection in infants. Understanding its regional molecular epidemiology is helpful for regulating efficient prevention practice. METHODS: A retrospective study was conducted to collected data from infants and pregnant women with culture-proven GBS disease in the largest women and children's medical center in Shanxi between January 2017 and September 2019. All GBS isolates were analyzed by multi-locus sequence typing (MLST) as well as distribution of pilus island (PI) genes. RESULTS: A total of 54 GBS isolates were obtained from 36 (66.7%) pregnant women and 18 (33.3%) infants with invasive disease. Among invasive GBS strains, the most common sequence type was ST10 (72.2%, P < 0.05), followed by ST23 and ST19. The ST10 strain was also the leading sequence type in colonizing pregnant women (44.4%, P < 0.05). All of the isolates carried at least one pilus island. The most frequently detected pilus island was PI-1+PI-2a (85.2%, P < 0.05), followed in turn by PI-2a and PI-2b. CONCLUSIONS: Our study demonstrates that one hypervirulent clone, sequence type 10, accounts for a large proportion of invasive GBS disease in infants and colonizing pregnant women, and the PI-1+PI-2a sub-lineages should be noted in infant infections.

Rapid personalized AMR diagnostics using two-dimensional antibiotic resistance profiling strategy employing a thermometric NDM-1 biosensor.

Antimicrobial resistance (AMR) threatens global public health and modern surgical medicine. Expression of ß-lactamase genes is the major mechanism by which pathogens become antibiotic resistant. Pathogens expressing extended spectrum ß-lactamases (ESBL) and carbapenemases (CP) are especially difficult to treat and are associated with increased hospitalization and mortality rates. Despite considerable effort, identification of ESBLs and CPs in a clinically relevant timeframe remains challenging. In this study, a two-dimensional AMR profiling assay strategy was developed employing panels of antibiotics (penicillins, cephamycins, oximino-cephalosporins and carbapenems) and ß-lactamases inhibitors (avibactam and EDTA). The assay required the development of a novel biosensor that employed New Delhi metallo-ß-lactamase-1 (NDM-1) as the sensing element. Functionally probing ß-lactamase activity using substrates and inhibitors combinatorically increased the informational content that enabled the development of assays capable of simultaneous, differential identification of multiple ß-lactamases expressed in a single bacterial isolate. More specifically, the assay enabled the simultaneous identification of ESBL and CP in mock samples, as well as in an engineered construct which co-expressed these ß-lactamases. The NDM-1 biosensor assay was 16 times and 8 times more sensitive than the ESBL Nordmann/Dortet/Poirel (NDP) and Carba Nordmann/Poirel (NP) assays, respectively. In a retrospective study, NDM-1 biosensor assays were able to differentially identify ESBLs, metallo-CPs and serine-CPs ß-lactamases in 23 clinical isolates with 100% accuracy. An assay algorithm was developed which accelerated data analytics reducing turnaround to <1 h. The assay strategy integrated with AI-based data analytics has the potential to provide physicians with a comprehensive readout of patient AMR status.

Generation of Acsl4 Gene Knockout Mouse Model by CRISPR/Cas9-Mediated Genome Engineering.

Acyl-CoA synthetase 4 (Acsl4) is involved in lipid synthesis and fatty acid degradation, and disruption of its function causes lipid metabolism disorder in various species. Herein, we report the generation of Acsl4 knockout (KO) mice using the CRISPR/Cas9 gene editing system to study its effects on lipid deposition. In this report, a large 12kb deletion in the Acsl4 gene was performed by coinjection of Cas9 mRNA and two guide RNAs (sgRNAs) into mouse fertilized oocytes. Six mutant mice carrying target mutations were examined by PCR analysis and direct sequencing. The gene modified mice remained healthy and displayed normal behavior. All the mutant F0 mice were mated with wild mice to produce the F1 generation, and only 1 F1 mutant mouse was obtained.

Diagnostic Value of Procalcitonin for Bacterial Meningitis in Children: A Comparison Analysis Between Serum and Cerebrospinal Fluid Procalcitonin Levels.

The aim of this study was to analyze and compare procalcitonin (PCT) levels in serum and cerebrospinal fluid (CSF) as tools for detecting bacterial meningitis (BM) in children. Serum and CSF PCT levels as well as albumin index (AI = CSF albumin/serum albumin × 1000) were measured from 29 BM, 25 viral meningitis (VM), and 47 non-meningitis patients. Differences between groups only for CSF PCT were significant. A stronger positive correlation between CSF PCT level and AI was observed in the BM patients ( R = 0.68, P < .001). As a predictor of BM, the area under the receiver operating characteristics curve for CSF PCT was greater than that of serum PCT (0.76 vs 0.67, P < .05) and a cutoff of ⩾0.085 ng/mL achieved 55.17% sensitivity and 95.83% specificity. High levels of CSF PCT may indicate loss of integrity of the blood-brain barrier; only CSF PCT has a diagnostic value for BM in children suspected meningitis.

[The forensic applications of sex chromosomes and mtDNA genetic markers].

This article summarizes the structure and heredity characteristics of sex chromosomes and mtDNA, presents the advantages and disadvantages of genetic markers' on them in the practice of forensic medicine which aims at promoting more widely using of the non-euchromosome DNA genetic markers in the forensic science.

[Impact of changes in land use and climate on the runoff in Liuxihe Watershed based on SWAT model].

SWAT model, an extensively used distributed hydrological model, was used to quantitatively analyze the influences of changes in land use and climate on the runoff at watershed scale. Liuxihe Watershed' s SWAT model was established and three scenarios were set. The calibration and validation at three hydrological stations of Wenquan, Taipingchang and Nangang showed that the three factors of Wenquan station just only reached the standard in validated period, and the other two stations had relative error (RE) < 15%, correlation coefficient (R2) > 0.8 and Nash-Sutcliffe efficiency valve (Ens) > 0.75, suggesting that SWAT model was appropriate for simulating runoff response to land use change and climate variability in Liuxihe watershed. According to the integrated scenario simulation, the annual runoff increased by 11.23 m3 x s(-1) from 2001 to 2010 compared with the baseline period from 1991 to 2000, among which, the land use change caused an annual runoff reduction of 0.62 m3 x s(-1), whereas climate variability caused an annual runoff increase of 11.85 m3 x s(-1). Apparently, the impact of climate variability was stronger than that of land use change. On the other hand, the scenario simulation of extreme land use showed that compared with the land use in 2000, the annual runoff of the farmland scenario and the grassland scenario increased by 2.7% and 0.5% respectively, while that of the forest land scenario were reduced by 0.7%, which suggested that forest land had an ability of diversion closure. Furthermore, the scenario simulation of climatic variability indicated that the change of river runoff correlated positively with precipitation change (increase of 11.6% in annual runoff with increase of 10% in annual precipitation) , but negatively with air temperature change (reduction of 0.8% in annual runoff with increase of 1 degrees C in annual mean air temperature), which showed that the impact of precipitation variability was stronger than that of air temperature change. Therefore, in face of climate variability, we need to pay attention to strong rainfall forecasts, optimization of land use structure and spatial distribution, which could reduce the negative hydrological effects (such as floods) induced by climate change.