Analysis of diverse β-lactamases presenting high-level resistance in association with OmpK35 and OmpK36 porins in ESBL-producing Klebsiella pneumoniae

Emerging extensively drug-resistant (XDR) Klebsiella pneumoniae due to the production of β-lactamases and porin loss is a substantial worldwide concern. This study aimed to elucidate the role of outer membrane porin (OMP) loss, AmpC, and carbapenemases among extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae strains with XDR phenotype. This study analyzed 79 K. pneumoniae from several clinical sources and detected ESBLs in 29 strains co-harbored with other β-lactamases using standard microbiological practices and phenotypic procedures. Minimum inhibitory concentrations (MICs) were determined against several antibiotics using Microscan WalkAway plus. OMP analysis was carried out using sodium dodecyl sulfate–polyacrylamide gel electrophoresis. ESBL, AmpC, and carbapenemase genes were detected using molecular methods. The microbiological analysis discovered 29 (36.7%) ESBL strains of K. pneumoniae, which showed the co-existence of 7 (24.1%) AmpC β-lactamases and 22 (75.9%) carbapenemases. Porin loss of OmpK35 was observed in 13 (44.8%) and OmpK36 in 8 (27.5%) K. pneumoniae strains. The strains were significantly associated with the intensive care unit (ICU) (p = 0.006) and urinary sources (p = 0.004). The most commonly detected gene variants in each β-lactamase class included 16 (55.2%) bla_CTX-M?1, 7 (100%) bla_CYM-2, 11 (50%) bla_NDM-1, and integron-1 was detected in 21/29 (72.4%) strains. MICs of cephalosporin, fluoroquinolone, carbapenem, aminoglycoside, and β-lactam combinations demonstrated a high number of XDR strains. Tigecycline (2 µg/mL MIC₅₀ and >32 µg/mL MIC₉₀) and colistin (1 µg/mL MIC₅₀ and 8 µg/mL MIC₉₀) presented lower resistance. ESBL K. pneumoniae strains with OmpK35 and OmpK36 porin loss demonstrate conglomerate resistance mechanisms with AmpC and carbapenemases, leading to emerging XDR and pan drug resistance.     

五虎汤对咳嗽变异性哮喘大鼠血清IL-33和TSLP水平的影响及机制研究

摘要 目的：探讨与研究五虎汤对咳嗽变异性哮喘大鼠血清白介素（Interleukin,IL）-33和胸腺基质淋巴细胞生成素（Thymic stromal lymphopoietin,TSLP）水平的影响及机制。方法：咳嗽变异性哮喘大鼠（n=48）随机平分为三组-模型组、孟鲁司特钠组与五虎汤组,模型组给予蒸馏水10 mL/(kg?d)灌胃,孟鲁司特钠组给予孟鲁司特钠10 mg/(kg?d)灌胃,五虎汤组给予五虎汤药液50 g/(kg?d)灌胃,1次/d,持续4周。结果：孟鲁司特钠组与五虎汤组治疗第2周、第4周的1min内桡鼻、打喷嚏次数少于模型组（P<0.05）,五虎汤少于孟鲁司特钠组(P<0.05)。孟鲁司特钠组与五虎汤组治疗第4周、第8周的白细胞计数及嗜酸性粒细胞百分率少于模型组,五虎汤少于孟鲁司特钠组（P<0.05）。孟鲁司特钠组与五虎汤组治疗第4周、第8周的血清IL-33、TSLP含量少于模型组（P<0.05）,五虎汤少于孟鲁司特钠组（P<0.05）。孟鲁司特钠组与五虎汤组治疗第4周、第8周的肺组织紧密连接蛋白-1（Zonula occludens-1,ZO-1）、钙粘附蛋白E（E-cadherin）蛋白相对表达水平高于模型组（P<0.05）,五虎汤组高于孟鲁司特钠组（P<0.05）。结论：五虎汤在咳嗽变异性哮喘大鼠的应用可能通过上调ZO-1、E-cadherin蛋白的表达,抑制血清IL-33和TSLP水平的表达,能促进缓解症状,降低白细胞计数及嗜酸性粒细胞百分率。     

Seroprevalence of neutralizing antibodies against adenovirus type 26 and 35 in healthy populations from Guangdong and Shandong provinces,China

Human adenoviruses type 26 (HAdV26) and type 35 (HAdV35) have increasingly become the choice of adenovirus vectors for vaccine application. However, the population pre-existing immunity to these two adenoviruses in China, which may reduce vaccine efficacy, remains largely unknown. Here, we established micro-neutralizing (MN) assays to investigate the seroprevalence of neutralizing antibodies (nAbs) against HAdV26 and HAdV35 in the general population of Guangdong and Shandong provinces, China. A total of 1184 serum samples were collected, 47.0% and 15.8% of which showed HAdV26 and HAdV35 nAb activity, respectively. HAdV26-seropositive individuals tended to have more moderate nAbs titers (201–1000), while HAdV35-seropositive individuals appeared to have more low nAbs titers (72–200). The seropositive rates of HAdV26 and HAdV35 in individuals younger than 20 years old were very low. The seropositive rates of HAdV26 increased with age before 70 years old and decreased thereafter, while HAdV35 seropositive rates did not show similar characteristics. Notably, the seropositive rates and nAb levels of both HAdV26 and HAdV35 were higher in Guangdong Province than in Shandong Province, but did not exert significant differences between males and females. The seroprevalence between HAdV26 and HAdV35 showed little correlation, and no significant cross-neutralizing activity was detected. These results clarified the characteristics of the herd immunity against HAdV26 and HAdV35, and provided information for the rational development and application of HAdV26 and HAdV35 as vaccine vectors in China.     

鹅白细胞介素 2基因的克隆与分子模型

对鸡、鸭、火鸡IL-2的核苷酸序列进行比较,在其保守区设计引物,通过RT-PCR方法扩增和克隆了鹅白介素2 (goIL-2) 的核苷酸序列。该序列由768 nt组成,编码一条由141个氨基酸组成的前体蛋白。goIL-2核苷酸序列和氨基酸序列与鸭IL-2(duIL-2)核苷酸序列和氨基酸序列的同源性为90.1%和83.6%,与鸡、火鸡和鹌鹑IL-2的同源性为69.7%-75%和61.0%-63.1%,与哺乳动物IL-2的同源性为25%-30%和14%-17%。氨基酸序列分析表明,N端存在一长21个氨基酸的信号肽,含有形成2个链内二硫键的4个半胱氨酸。goIL-2 mRNA的体外表达动力学分析表明,脾脏T淋巴细胞经Con A诱导2 h至24 h均可检测到goIL-2 mRNA的表达。三维结构预测表明,goIL-2蛋白由A、B、C、D 4个α-螺旋和2个?-折叠构成。遗传进化分析表明,goIL-2和duIL-2的亲缘关系最近。     

CRP、纤维蛋白原及白细胞计数水平在COPD临床诊断中的作用

为了研究C-反应蛋白(CRP)、纤维蛋白原(FIB)及白细胞计数(WBC)与慢性阻塞性肺疾病急性(COPD)的相关性及用于诊断慢性阻塞性肺疾病的临床意义,本研究将2015年8月至2017年2月在本院呼吸与危重症医学科住院治疗的60例慢性阻塞性肺疾病急性加重期患者作为AECOPD组,并选择同期住院的60例慢性阻塞性肺疾病稳定期患者设为SCOPD组,60例健康人员作为健康对照组,用受试者工作特征曲线(receiver operator characteristic curve,ROC curve)分析血清CRP、FIB、WBC水平及诊断COPD疾病的临床价值。研究结果表明,AECOPD组及SCOPD组血清CRP、FIB及WBC水平均明显高于健康对照组(tCRP=7.14,tFIB=2.72,tWBC=9.82),AECOPD组血清CRP、FIB及WBC水平(tCRP=37.29,tFIB=5.28,tWBC=14.36)也明显高于SCOPD组(tCRP=14.45,tFIB=4.71,tWBC=12.77),差异均有统计学意义(均p<0.05)。同时,在SCOPD者中,CRP水平与FIB和WBC呈正相关(γ=0.687,0.512,均p<0.05),FIB和WBC也呈正相关(γ=0.445,0.512,p<0.05);在AECOPD组中,CRP水平与FIB和WBC呈正相关(γ=0.733,0.587,均p<0.05),FIB和WBC也具有相关性(γ=0.676,p<0.05)。本研究初步结论认为,CRP、FIB、WBC水平与COPD患者的病情严重程度存在明显相关性,联合CRP、FIB、WBC因子检测有助于鉴别COPD恶化程度,并可作为COPD疾病的监测指标。     

Michael Ter-Avanesyan (1949-2018) - life in science

This commentary describes scientific path and accomplishments of our late colleague, Prof. Michael D. Ter-Avanesyan, who made several seminal contributions into prion research.     

Hyperactive Innate Immunity Causes Degeneration of Dopamine Neurons upon Altering Activity of Cdk5

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Activation of BV2 microglia by lipopolysaccharide triggers an inflammatory reaction in PC12 cell apoptosis through a toll-like receptor 4-dependent pathway

Microglia play an important role in neuronal protection and damage. However, the molecular and cellular relationship between microglia and neurons is unclear. We carried out a prospective study to detect that activation of BV2 microglia induced PC12 cell apoptosis in vitro through the TLR4/adapter protein myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway. BV2 microglia were treated with different concentrations of LPS for 24 h. Western blot was utilized to detect the expression of TLR4 and the downstream signaling pathway. The level of inflammatory mediator was quantified using a specific ELISA kit. The supernatant of 10 μg/ml LPS-treated BV2 cells was used as conditioned medium (CM). PC12 cells were co-culture with CM for 24 h. Cell viability was determined by MTT assay and cell apoptosis was tested by flow cytometry. BV2 microglia were treated with 10, 20, or 30 μg/ml LPS for 24 h. The expression of TLR4, MyD88, and NF-κB significantly increased. When PC12 cells were co-cultured with CM for 24 h, cell viability decreased. CM up-regulated the Bax level and down-regulated the Bcl-2 protein level in PC12 cells. PC12 cells pretreated with interleukin-1 receptor antagonist (IL-1RA) for 30 min, significantly alleviated CM-induced PC12 cell apoptosis. These results suggest that BV2 microglia activated by LPS triggered TLR4/MyD88/NF-κB signaling pathway that induced the release of IL-1β and could participate in the PC12 cells injury.     

Cyclophilin D deficiency protects against the development of mitochondrial ROS and cellular inflammation in aorta

Introduction

Inflammation and oxidative stress are closely correlated in the pathology of cardiovascular disease. Mitochondrial cyclophilin D (CypD), the important modulator for mPTP opening, is increasingly recognized as a key regulator of cellular ROS generation. Besides, its association with cell inflammation is also being discovered. However, the effects of CypD in modulating vascular inflammatory response is unknown. We sought to investigate whether CypD deficiency attenutes vascular inflammation under physical conditions.