Molecular characterization of rifabutin-resistance in refractory Helicobacter pylori infection in Taiwan.

OBJECTIVES: To explore the molecular characteristics of rpoB, encoding ß-subunit of DNA-directed RNA polymerase, and unravel the link to rifabutin-resistance in patients with refractory Helicobacter pylori infection. METHODS: From January 2018-March 2021, a total of 1590 patients were screened for eligibility to participate in the study. Patients with refractory H. pylori infection were confirmed by using the (13C)-urea breath assay. All enrolled patients underwent esophagogastroduodenoscopy, and biopsies were taken for H. pylori culture and antibacterial susceptibility testing. Sequence analysis of rpoB was conducted for all rifabutin-resistant isolates. RESULTS: In total, 70 patients were diagnosed with refractory H. pylori infection, and 39 isolates were successfully cultured. Amongst, 10 isolates were identified as rifabutin-resistance and nine isolates exhibited at least one amino acid substitution in RpoB. Isolates with a minimal inhibitory concentration >32 mg/l displayed a higher number of mutational changes in RpoB than the others. Additionally, more amino acid substitutions in RpoB correlated with developing a higher minimal inhibitory concentration for H. pylori rifabutin-resistance. CONCLUSION: Our findings highlight the relationship between rifabutin-resistance in refractory H. pylori infection and specific mutations in RpoB, which will aid the clinical selection of appropriate antibacterial agents with better therapeutic effects.

Multiple amino acid substitutions in penicillin-binding protein-1A confer amoxicillin resistance in refractory Helicobacter pylori infection.

BACKGROUND: Amoxicillin resistance in Helicobacter pylori is mainly associated with mutations in penicillin-binding protein-1A (PBP-1A). However, the specific amino acid substitutions in PBP-1A that confer amoxicillin resistance in H. pylori remain to be investigated. OBJECTIVE: This study aimed to investigate the molecular mechanism underlying amoxicillin resistance in patients with refractory H. pylori infection. METHODS: Esophagogastroduodenoscopy (EGD) was performed in patients with persistent H. pylori infection after at least two courses of H. pylori eradication therapy between January-2018 to March-2021. Refractory H. pylori was cultured from the gastric biopsy specimens. Antibiotic susceptibility testing was conducted to determine the minimum inhibitory concentrations (MICs). Sequence analysis of pbp-1A was performed for amoxicillin-resistant strains. RESULTS: Thirty-nine successfully cultured isolates were classified as refractory H. pylori isolates, and seventeen isolates were resistant to amoxicillin (MIC > 0.125 mg/L). Sequence analysis of resistant strains showed multiple mutations in the C-terminal region of PBP-1A that conferred amoxicillin resistance in H. pylori. However, the number of PBP-1A mutations did not correlate with the high MICs of amoxicillin-resistant isolates. Notably, some amino acid substitutions were identified in all Taiwanese isolates with history of eradication failure but not in published amoxicillin-susceptible strains, suggesting that the mutations may play a role in conferring antibiotic resistance to these strains. CONCLUSIONS: Our results show that amoxicillin resistance in refractory H. pylori is highly correlated with numerous PBP-1A mutations that are strain specific. Continuous improvements in diagnostic tools, particularly molecular analysis approaches, can help to optimize current antimicrobial regimens.

Initial radiographic tracheal ratio in predicting clinical outcomes in croup in children.

Croup is the leading infectious disease resulting in pediatric upper airway obstruction. Our purpose is to analyze diverse features of neck radiographs could be seen as an objective tool to predict outcomes in patients with croup. One hundred and ninety-two patients were prospectively recruited in pediatric emergency department with diagnosis of croup. The initial Westley score (WS), presence of steeple sign, extent of narrowing, and narrowing ratio on soft tissue neck radiographs were determined before and after treatments. The extent of frontal narrowing, extent of lateral narrowing, frontal ratio (FR), and lateral ratio (LR) were investigated to predict clinical outcomes in patients with croup. The extent of frontal/lateral narrowing and LR had significant correlation with outpatient status. Almost 71% of patients with FR values below 0.23 stayed in the hospital longer, whereas nearly 98% of patients with FR vales above 0.65 could be discharged. About 85% of patients with LR below 0.45 hospitalized longer. The LR and FR were significantly correlated with the severity and admission rate in croup. The LR > 0.6 and FR > 0.65 may indicate low risk in patients with croup, whereas the FR < 0.23 or LR < 0.45 may indicate the need of stay in hospital for further treatment and monitor.

Clinical significance of diabetes on symptom and patient delay among patients with acute myocardial infarction-an analysis from China Acute Myocardial Infarction (CAMI) registry.

BACKGROUND: Diabetes is frequently associated with poor prognosis among acute myocardial infarction (AMI) patients. Patients with these comorbidities often have atypical symptoms and subsequent delay in treatment. Few studies have reported detailed AMI symptoms in patients with diabetes. This study compared AMI symptoms and presentation characteristics between diabetics and non-diabetics. METHODS: We included patients from the China AMI registry diagnosed with AMI between January 2013 and September 2014. Baseline characteristics, symptomology, and delay in treatment were compared between diabetics and non-diabetics. Multivariable logistic regression analysis was used to explore independent predictors of atypical symptoms. RESULTS: A total of 4450 (20.2%) patients had diabetes. They were older, more often women, higher in body mass index, and more likely to have non-ST segment elevation myocardial infarction. Fewer diabetic patients presented with persistent precordial chest pain (63.1% vs. 68%, P < 0.0001), diaphoresis (60.1% vs. 65.6%, P < 0.0001), fatigue (16.7% vs. 18.3%, P = 0.0123), and incontinence (0.4% vs. 0.7%, P = 0.0093). Time to hospital presentation was longer among patients with diabetes than those without. In multivariable analysis, diabetes was identified as an independent predictor of atypical symptoms (OR: 1.112, 95% CI: 1.034-1.196). CONCLUSIONS: Our study is the first large-scale study providing evidence that diabetics are less likely to present with typical chest pain and more likely to experience treatment delay when suffering from an AMI. Our results may increase clinician awareness of recognizing AMI patients rapidly to reduce diagnosis and treatment delay, particularly in the context of diabetes.

Analysis of Microbial Contamination Status of 9 Kinds of Chinese Herbal Pieces from Guangxi Regions / 中国药师

Objective:To investigate the microbial contamination status of Chinese herbal pieces from Guangxi regions and provide reference for the microbial limit standard. Methods:According to Chinese Pharmacopoeia (2015 edition), the herbal pieces were analyzed for the total number of aerobe microbial, yeasts, molds, thermophilic bacteria and bile-resistant gram-negative bacteria,and salmonella was also detected. Results:In 90 batches of Chinese herbal pieces,the lg average value of the total number of aerobe microbial was 3.7,and that of the total yeasts and molds was 1.7,that of thermophilic bacteria was 0.9 and that of bile-resistant gram-negative bacteria was 1.1,and Salmonella was not detected out. There were statistically significant differences (P < 0.05) in the microbial contamination levels of herbal pieces with different processing techniques and packaging materials. Conclusion:According to different processing methods and administration, microbial limit standard should be established for classification in order to guide the standardized production of Chinese herbal pieces and improve their quality gradually.

Analysis of microbial community of heat resistant microorganisms in Chinese herbal pieces / 中国中药杂志

To investigate the composition and diversity of heat resistant microorganisms in contaminated Chinese herbal pieces. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) protein fingerprinting and 16S rRNA high-throughput sequencing of Illumina Miseq were used to analyze the heat resistant microbial community of 9 varieties of Chinese herbal pieces. Stem pieces (Spatholobi Caulis, Tetrapanacis Medulla, Stachyuri Medulla) showed highest detection rate and most species of contaminants; However fruit pieces (Schisandrae Sphenantherae Fructus) had the lowest detection rate and least species of contaminants; among root pieces, the detection rate and number of contaminants species were lower in Tuber Dioscoreae Persimilis and Rehmanniae Radix Praeparata. The heat resistant microbial community was mainly of Bacillaceae and Paenibacillaceae, and Bacillus showed the highest detection rate among them, followed by Brevibacillus, Paenibacillus, and Solibacillus. The rest genus in high-throughput sequencing analysis included Enterobacter, Brevundimonas, Leuconostoc, Methylobacterium, Dechloromonas, Pantoea, Klebsiella, and Erwinia. There were potential risk factors in heat resistant microbial community of Chinese herbal pieces, so we shall improve the microbial limit standard, strictly control the pathogenic bacteria in the product, and strengthen the supervision and management in production and circulation of Chinese herbal pieces.

Effect of cobra venom NGF on inducing apoptosis of LX2 cells by inhibiting Akt signaling pathway and its mechanism / 中国药理学通报

Aim To study the effect of cobra venom nerve growth factor ( NGF) on inducing the apoptosis of LX2 cells, the key cells of hepatic fibrosis , through Akt signaling pathway and its underlying mechanism .Methods CCK-8 method was used to detect the pro-liferation of LX2 cells at different concentrations of NGF and LY294002 .Flow cytometry was applied to detect the effect of NGF on the apoptosis of LX 2 cells. Western blot was used to study the effects of NGF and LY294002 respectively , and their combination on the p-Akt protein level .Results NGF could decrease the survival rate of LX2 cells, and the minimum effective concentration was 1mg· L-1; it increased the apopto-sis rate of LX2 cells within the rise of concentration un-der a certain of range and decreased the expression level of p-Akt, but it had no significant effect on the ex-pression of Akt .Conclusions NGF may promote the apoptosis of LX2 cells by inhibiting the activation of PI3K/Akt signaling pathway in a concentration-de-pendent manner .The study of the pathogenesis of liver fibrosis is significant for the clinical treatment of liver fibrosis.

[Effect of the change in sulphate and dissolved oxygen mass concentration on metal release in old cast iron distribution pipes].

To understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1). With the increase of sulfate concentration, the effluent concentrations of As, Cr, Cu, Zn and Ni also increased obviously, however, the effluent concentrations of these metals were lower than the influent concentrations under most circumstances, which indicated that adsorption of these metals by pipe corrosion scales occurred. Increasing DO within a certain range could significantly inhibit the iron release.

[Diversity and bacteria community structure of activated carbon used in advanced drinking water treatment].

Two granular activated carbon (GAC) samples with 1.5 a and 5 a age were collected, Bacterial genome DNA was extracted for the 16S rDNA gene amplification, and then a bacterial 16S rDNA gene clone library was constructed. After the phylogenetic analysis of 16S rDNA sequences, bacterial diversity and community structure of two activated carbon biofilm sample were studied. The results showed the bacteria in GAC with 5 a age could be divided into 11 groups, which were as follows alpha-Proteobacteria (26.5%), beta-Proteobacteria (16.3%), delta-Proteobacteria (16.3%), Planctomycetes (12.2%), Gemmatimonadetes (6.1%), Acidobacteria (4.1%), Nitrospira (2.0%), gamma-Proteobacteria (2.0%), Bacteroidetes (2.0%), Actinobacteria (2.0%), Unclassified Bacteria (10.2%). The bacteria in GAC with 1.5 a age could be divided into 10 groups, which were as follows alpha-Proteobacteria (21.6%), Planctomycetes( 10.8%), Bacteroidetes (10.8%), beta-Proteobacteria (9.0%), Acidobacteria (9.0%), Nitrospira (7.2%), detla-Proteobacteria (7.2%), Unclassified Proteobacteria (5.4%), Gemmatimonadetes (3.6%), Unclassified Bacteria (14.4%). The results revealed a variety of bacterial divisions on the studied GAC biofilm. Proteobacteria had the highest share in the two total clones, and alpha- and beta-Proteobacteria were on a dominant position. A relatively high proportion of delta-Proteobacteria was observed in the biofilm of GAC with 5 a age, and Nitrospira was in a minor proportion. However, a totally converse condition appeared in GAC with 1.5 a age. Two pathogenic bacteria, Afipia and Chryseobacterium, were detected in analyzed GACs, which implies a potential microbial risk in water supply.

[Case study of red water phenomenon in drinking water distribution systems caused by water source switch].

Red water phenomenon occurred in some communities of a city in China after water source switch in recent days. The origin of this red water problem and mechanism of iron release were investigated in the study. Water quality of local and new water sources was tested and tap water quality in suffered area had been monitored for 3 months since red water occurred. Interior corrosion scales on the pipe which was obtained from the suffered area were analyzed by XRD, SEM, and EDS. Corrosion rates of cast iron under the conditions of two source water were obtained by Annular Reactor. The influence of different source water on iron release was studied by pipe section reactor to simulate the distribution systems. The results indicated that large increase of sulfate concentration by water source shift was regarded as the cause of red water problem. The Larson ratio increased from about 0.4 to 1.7-1.9 and the red water problem happened in the taps of some urban communities just several days after the new water source was applied. The mechanism of iron release was concluded that the stable shell of scales in the pipes had been corrupted by this kind of high-sulfate-concentration source water and it was hard to recover soon spontaneously. The effect of sulfate on iron release of the old cast iron was more significant than its effect on enhancing iron corrosion. The rate of iron release increased with increasing Larson ratio, and the correlation of them was nonlinear on the old cast-iron. The problem remained quite a long time even if the water source re-shifted into the blended one with only small ratio of the new source and the Larson ratio reduced to about 0.6.

[Analysis of microbial community of a Beijing simulator water distribution system].

Identification of compositions of the biofilm in a Beijing simulator water distribution system pipe networks by PCR and single strand conformation polymorphism (PCR-SSCP) technique and analysis of its heterotrophic bacterial by heterotrophic plate count (HPC) were performed. Results showed that when the water velocities were same, the count of heterotrophic bacterial on the zinficated steel wall was about five times of the PVC. On the other hand, when the pipe materials were zinficated steel, the count of heterotrophic bacterial in the deadwater pipe wall was about 1/5 of the 0.6 m/s region. The difference of the bacterial count maybe related to the smooth of the water pipe surface and the velocity of flow which affected the attachment of the microorganisms and the quantity of O2 and nourishment, respectively. Same SSCP electrophoresis profiles were observed between samples from different material pipes and water velocities. After sequencing and contrasting with the GenBank, the identity of three bands from the SSCP gel with Bacillus cereus (GenBank AB190077), Peudomonas sp. yged143 (GenBank EF419342) and a unclassified bacteria, Bacterium UASWS0134 (GenBank DQ190347) were 100%, 99% and 94%, respectively. The sameness of the microbial community structure may be induced by the samples which were from the same simulator system and the sampling regions were near and the microorganisms could transform in these regions easily. The observed potential pathogens of Bacillus cereus and Peudomonas sp. should lead to a consideration of the microbiology safety of drinking water.