急诊重症监护室血流感染患者临床结局的风险因子探讨

目的探讨急诊重症监护室(emergency intensive care unit,EICU)血流感染患者临床结局的风险因子,为临床决策提供依据。方法回顾性收集2019年1月至2023年4月我院就诊的141例EICU血流感染患者的病历资料及血培养记录,采用Logistic回归分析患者死亡的危险因素,运用Cox回归分析上述因素与患者生存时间和临床结局的关系。结果在141例EICU血流感染患者中,两种及以上细菌混合血流感染[比值比(OR)=5.68,95%置信区间(CI):1.20~26.98,P<0.05]及多重耐药菌血流感染(OR=6.39,95%CI:2.78~14.67,P<0.01)与患者死亡具有显著相关性;是否根据药敏结果及时调整用药[风险比(HR)=0.47,95%CI:0.30~0.74]和多重耐药菌血流感染(HR=2.02,95%CI:1.28~3.20)是EICU血流感染患者死亡的风险因子(P<0.01)。结论尽早采集血培养,明确感染病原菌,精准用药控制感染,可以有效降低患者的死亡率。

电裂解芯片及其在细菌核酸分析中的应用

近年来,由于各种细菌引起的疾病不断爆发,细菌核酸检测已成为常用的实验室诊断方法。细菌核酸提取是细菌分类和鉴定的关键步骤,也是医学诊断、药物筛选的重要技术之一。目前的细菌核酸提取以化学裂解方法为主,其存在明显的缺点,如样品量大、化学试剂污染等。因此,研究快速、简单、无化学污染的检测装置具有重要意义。该研究设计了一种微流控芯片在直流电场下裂解各种细菌并提取核酸。研究了电场强度、电极间距、裂解时间、氧化铟锡电极方阻及电极宽度对核酸提取的影响。结果表明,在3.0 kV/mm的电场强度下,该芯片可在3 s内裂解大肠杆菌、金黄色葡萄球菌、表皮葡萄球菌、枯草芽孢杆菌、肺炎克雷伯氏菌、鼠伤寒沙门氏菌和铜绿假单胞菌等多种细菌,并释放出核酸。提取的核酸无需纯化,可直接用于PCR检测。该芯片与实时荧光定量PCR联用检测细菌DNA的线性范围为10-18~10^(-10)mol/L,检出限低至4.2×10^(-18)mol/L。不同类型的细菌需根据其性质适当调整最佳裂解条件。该研究为病原体分析和细菌感染的医学诊断提供了一种简单、快速、高效且无化学试剂污染的核酸提取方法。

利用mPCR方法检测巴氏奶中致病菌的鲁棒性研究

为解决巴氏奶货架期短与致病菌传统检测方法耗时长相矛盾问题,建立一种检测巴氏奶中的阪崎克罗诺杆菌、大肠杆菌和沙门氏菌的鲁棒性多重聚合酶链式反应(multiple polymerase chain reaction,mPCR)方法。旨在常规mPCR的基础上深入研究,提高方法的准确性和稳定性。首先,针对每个目标菌株选择两种基因,并设计两组特异性引物,建立两套mPCR扩增体系,进行双重检测;然后,在不改变方法灵敏度的前提下,对优化了的退火温度进行范围稳定性选择;最后,将提出方法与国标方法 GB 4789.40-2016、GB 4789.38-2012、GB 4789.4-2016进行比较,同时检测人工污染样品并评价应用效果。结果表明,第一套mPCR检测巴氏奶中三种致病菌可在退火温度59~59.5℃(温差0.5℃)的范围内,具有较好的检测准确性和稳定性,灵敏度为10 CFU/mL。第二套mPCR检测巴氏奶中三种致病菌可在退火温度57.5~58.5℃(温差1℃)的范围内,不影响方法的准确性和稳定性,灵敏度为10 CFU/mL。采用建立的鲁棒性mPCR方法对人工污染的50份巴氏奶样品进行检测,检测结果与国标方法一致。在检测时效上需要4 h,较国标方法(检测时间为62~148 h)显著(P<0.05)缩短检测时间。该方法对微生物流行病学调查和研究,尤其是对巴氏奶中致病菌的快速检测和安全控制具有一定的实际应用价值。

Comparison of extended spectrum β-lactamasesproducing Escherichia coli with non-ESBLsproducing E.coli:drug-resistance and virulence

BACKGROUND:The virulent factors of Escherichia coli(E.coli) play an important role in the process of pathopoiesis.The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-lactamases(ESBLs)-producing E.coli and non-ESBLs-producing E.coli to provide a reference for physicians in management of hospital infection.METHODS:From October 2010 to August 2011,96 drug-resistant strains of E.coli isolated were collected from the specimens in Qingdao Municipal Hospital,Qingdao,China.These bacteria strains were divided into a ESBLs-producing group and a non-ESBLs-producing group.Drug sensitivity tests were performed using the Kirby-Bauer(K-B) method.Disinfectant gene,qacEA1-sull and 8 virulence genes(CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1) were tested by polymerase chain reaction(PCR).RESULTS:Among the 96 E.coli isolates,the ESBLs-producing E.coli comprised 46(47.9%)strains and the non-ESBLs-producing E.coli consisted of 50(52.1%) strains.The detection rates of multiple drug-resistant strain,qacEA1-sull,CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1 in 46ESBLs-producing E.coli isolates were 89.1%,76.1%,6.5%,69.6%,69.6%,89.1%,10.9%,26.1%,8.7%,and 19.6%,respectively.In the non-ESBLs-producing E.coli strains,the positive rates of multiple drug-resistant strain,qacEA1-sull,CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1 were 62.0%,80.0%,16.0%,28.0%,64.0%,38.0%,6.0%,34.0%,10.0%,and 24.0%,respectively.The difference in the detection rates of multiple drug-resistant strain,hlyA and VT1 between the ESBLs-producing E.coli strains and the non-ESBLs-producing E.coli strains was statistically significant(P<0.05).CONCLUSION:The positive rate of multiple drug-resistant strains is higher in the ESBLsproducing strains than in the non-ESBLs-producing strains.The expression of some virulence genes hlyA and VT1 varies between the ESBLs-producing strains and the non-ESBLs-producing strains.Increased awareness of clinicians and enhanced testing by laboratories are required to reduce treatment failures and prevent the spread of multiple drug-resistant strains.

Antibiotic-Resistant Bacterial Group in Field Soil Evaluated by a Newly Developed Method Based on Restriction Fragment Length Polymorphism Analysis

Spreading of antibiotic resistant bacteria into environment is becoming a major public health problem, implicating affair of the indirect transmission of antibiotic resistant bacteria to human through drinking water, or vegetables, or daily products. Until now, the risk of nosocomial infection of antibiotic resistant bacteria has mainly been evaluated using clinical isolates by phenotypic method. To evaluate a risk of community-acquired infection of antibiotic resistant bacteria, a new method has been developed based on PCR-RFLP without isolation. By comparing restriction fragment lengths of the 16S rDNA gene from bacterial mixture grown under antibiotic treatment to those simulated from the DNA sequence, bacterial taxonomies were elucidated using the method of Okuda and Watanabe [1] [2]. In this study, taxonomies of polymyxin B resistant bacteria group in field soils, paddy field with organic manure and upland field without organic manure were estimated without isolation. In the both field soils, the major bacteria grown under the antibiotic were B. cereus group, which had natural resistance to this antibiotic. In field applied with organic manure, Prevotella spp., and the other Cytophagales, which were suggested to be of feces origin and to acquire resistance to the antibiotic, were detected. When numbers of each bacterial group were roughly estimated by the most probable number method, B. cereus group was enumerated to be 3.30 × 106 MPN/g dry soil in paddy field soil and 1.32 × 106 MPN/g dry soil in upland filed. Prevotella spp. and the other Cytophagales in paddy field were enumerated to be 1.31 × 106 MPN, and 1.07 × 106 MPN·g-1 dry soil.

Epidemiological Characteristics, Resistance Patterns and Spread of Gram-Negative Bacteria Related to Colonization of Patients in Intensive Care Units

Our aim was to determine the epidemiological characteristics, the resistance patterns and the spread of Gram negative bacteria related to colonization of patients in adult Intensive Care Units. Methods: A prospective cohort of patients colonized and/or infected with Gram negative bacteria was conducted at two adult ICUs from hospitals in Brazil (April 2012 to February 2013). Nasal, groin and perineum swabs were performed. Samples were incubated on MacConkey and cetrimide agar (48 h at 37℃) and identification tests (Vitek-BioMérieux), antibiogram (Bauer-Kirby method), Carba NP test, Polymerase Chain Reaction (PCR) and sequencing were performed. The patterns of resistant microorganisms were compared by rep-PCR (Diversilab). Results: There were 53 cases of colonization. In these cases, we identified imipenem-resistant Acinetobacter baumannii (51%), Pseudomonas aeruginosa (32%), Klebsiella pneumoniae ESBL (38%) or imipenem resistant (5.6%). The use of antimicrobials and medical devices were related to colonization (p The resistance patterns expressed by Klebsiella pneumoniae were ESBL (CTX-M, SHV e TEM) and KPC2. A verified profile of Acinetobacter baumannii was related to OXA-23 and OXA-253 (OXA-143 variant). The profiles ESBL and KPC2 expressed by Klebsiella pneumoniae were distributed between the both ICUs. The distribution of OXA-23 and OXA-253 was verified only in one ICU. The similarity of strains ranged from 80% to 95%, highlighting the horizontal transference of these microorganisms.

Preliminary Study on the Antibacterial Activity of Six Medicinal Plants against Two Naso-Pharyngeal Pathogens—Streptococccus pyogenes and Pseudomonas aeruginosa

Objective: The objective is to study the antibacterial activity of six medicinal plants against two naso-pharyngeal pathogens and determination of total phenol contents in ethanol extracts of those plants. Methods: Different serial concentrations (0.05 g/mL, 0.1 g/mL, 0.2 g/mL, 0.4 g/mL) of ethanolic and acetone extracts of Piper nigrum L. (Piperaceae), Ocimum sanctum Linn., Plectranthus amboinicus L. (Lamiaceae), Ayapana triplinervis M.Vahl. (Asteraceae), Cinnamomum zeylanicum L. (Lauraceae), Allium schoenoprasum Linn. (Liliaceace) were evaluated for the antibacterial activity using disc diffusion method against gram positive Streptococcus pyogenes and gram negative Pseudomonas aeruginosa. The extracts were prepared from different parts of the plants. The total phenol content was estimated using folin-ciocaltau reagent in catechol equivalents. Results: Majority of the extracts had inhibitory effect against the tested bacteria at different concentrations. In ethanol extracts, Plectranthus amboinicus exhibited the maximum zone of inhibition (14 mm) at 0.05 g/mL concentration against Streptococcus pyogenes, and Ocimum sanctum showed highest zone of bacterial inhibition (19 mm) at 0.05 g concentration against Pseudomonas aeruginosa. In acetone extracts, Piper nigrum had the maximum zone of bacterial inhibition (17 mm) in 0.4 g/mL concentration against Streptococcus pyogenes and Cinnamomum zeylanicum and Allium schoenoprasum exhibited the highest zone of bacterial inhibition (0.4 g/mL) against Pseudomonas aeruginosa. The ethanol extract of Plectranthus amboinicus contained the highest amount of phenol (0.8 mg/mL) and Allium schoenoprasum contained the lowest amount (0.62 mg/mL). In acetone, Cinnamomum zeylanicum contained highest phenol content (0.78 mg/mL). Conclusion: All these investigations pave way to the molecular modeling of the lead phyto compounds present in the studied plants, and also in finding out their biochemical action in various metabolic pathways and reactions of infection.

Evaluation of the Method Based on Restriction Fragment Length Polymorphism Analysis as Simple Analysis Method of Lactic Acid Bacteria in Foods

Lactic acid bacteria have not only been used to produce various kinds of fermented food, but also used as probiotic products. As lactic acid bacterial group was consisted from diverse genera, a simple inspection method by which numbers and contained microorganisms could be automatically analyzed without any preliminary information was required to use them more effectively. In this manuscript, lactic acid bacterial groups in commercial products of kimuchi, komekouji-miso, and yoghurt were identified and enumerated by our newly developed method [1]-[3], to evaluate whether the method could be used as an inspection method of various food samples. In kimuchi, numerically dominant bacteria were Lactobacillus sakei, and L. casei (1.4 × 104 MPN g-1) and Leuconostoc spp. (l.4 × 104 MPN). In kouji-miso, numerically dominant bacteria was Bacillus spp. (3 × 103 MPN), which mainly included B. subtilis group and B. cereus group. Lactic acid bacteria such as Lactobacillus spp., or Lactococcus spp., included in the komekouji-miso, could be enumerated after 3 days incubation (1.24 × 104 MPN), but not detected after 7 days incubation. In yoghurt A and C, Lactococcus lactis was detected as numerically dominant lactic acid bacteria (3.0 × 105 MPN). In yoghurt B, Lactobacillus spp., or Lactococcus spp., was detected not only by a culturebased method but also by an unculture-based method, although there was a difference between the both estimated numbers. The present results suggested that the method might become useful as a simple inspection method of food microorganisms, because time and labor of the analysis could be reduced by using an unculture-based method and MCE-202 MultiNA. In this study, Bifidobacteriium spp. was not detected in B and C yoghurt, in spite of indicating their existence, and numbers of lactic acid bacteria were lower than the level of the daily product regulation, because 16S rDNA of Bifidobacteriium spp. might not be amplified by the used PCR condition. The PCR condition must be changed so as to amplify Bifidobacterium spp., before the method will be used as an inspection method for lactic acid bacteria.

A New Evaluation Method for Antibiotic-Resistant Bacterial Groups in Environment

In the present manuscript it was presented whether spreading of antibiotic resistant bacterial groups in environment could be monitored by our newly developed method by enumerating antibiotic resistant bacterial groups in various biological wastes and composts. Although the numbers were not so high, diverse kinds of colistin resistant bacteria (25 mg·L-1) were included in row cattle feces (1.78 × 104 MPN g-1) and cattle feces manure (>3.84 × 104 MPN g-1). Compost originated from leftover food (>44.8 × 104 MPN g-1) and shochu lee (>320 × 104 MPN g-1) included higher numbers of chlortetracycline resistant Pseudomonas sp., (25 mg·L-1), and row cattle feces included higher numbers of chlortetracycline resistant Enterobacteriacea (15.7 × 104 MPN g-1), which mostly consisted from Pantoea sp. or Xenorhobdus doucetiae. Numbers of multi drug resistant bacteria, resistant to 25 mg·L-1 of ciprofloxacin, streptomycin, chloramphenicol, and ampicillin, were the highest in row cattle feces (>143.6 × 104 MPN g-1), followed by cattle feces manure (4.19 × 104 MPN g-1), and shochu lee (0.36 × 104 MPN g-1), which included diverse kinds of bacterial group. The present results indicated that higher numbers of multi drug resistant bacteria were typically found in row cattle feces, and the method was found suitable to enumerate and identify them. These results suggested that the method might become their environmental risk evaluation method.

2019—2021年住院儿童多重耐药菌分布及耐药性分析

目的对2019—2021年青岛某医院住院儿童多重耐药菌(MDRO)分布特点及耐药性进行分析,为该地区儿童MDRO的预防与治疗提供参考依据。方法分析2019年1月1日—2021年12月31日住院儿童送检标本分离的MDRO情况,对检出的MDRO的分布、耐药性进行分析。结果2019—2021年共检出MDRO 917株,其中占前4位的分离菌株分别为产超广谱β-内酰胺酶大肠埃希菌(ESBLs-EC)440株(47.98%)、耐甲氧西林金黄色葡萄球菌(MRSA)234株(25.52%)、产超广谱β-内酰胺酶肺炎克雷伯菌(ESBLs-KP)148株(16.14%)、耐碳青霉烯肺炎克雷伯菌(CRKP)36株(3.93%)。CRKP、ESBLs-KP、耐碳青霉烯类鲍曼不动杆菌(CRAB)、耐碳青霉烯类铜绿假单胞菌(CRPA)检出率比较差异有统计学意义(χ^(2)=6.276~19.335,P<0.01)。检出MDRO前3位的标本分别是痰液、脓液、血液,占比分别为39.04%、28.90%、12.00%。3年间检出MDRO最多的科室为儿内科(368株,40.13%),耐碳青霉烯类大肠埃希菌(CREC)、CRKP、MRSA检出最高的科室为儿内科,ESBLs-EC检出最高的为儿外科,ESBLs-KP检出较高的科室为儿内科和重症监护室(ICU),CRAB、CRPA主要为儿童监护室检出。CREC对米诺环素、替加环素、多黏菌素B、美罗培南、亚胺培南敏感,敏感率>90.00%;CRAB对米诺环素、替加环素、多黏菌素B敏感率为100.00%;CRPA对米诺环素、多黏菌素B敏感率为100.00%;MRSA对万古霉素、利奈唑胺、替加环素的敏感率为100.00%;CREC对米诺环素、替加环素、美罗培南、亚胺培南、厄他培南、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、阿米卡星敏感,敏感率>90.00%;MRSA是住院儿童检出的革兰染色阳性的优势菌群,其对红霉素、克林霉素的耐药率在90.00%以上。结论2019—2021年检出的MDRO以产ESBLs-EC、MRSA、ESBLs-KP为主,ICU、儿内科应纳入MDRO感染防控管理的重点科室。

新冠疫情期间住院患儿院内感染及多重耐药菌变化趋势分析

目的:回顾性分析新冠疫情对住院患儿院内感染产生的影响以及多重耐药菌的变化。方法:收集2017年至2022年的医院感染监测数据,包括重点关注部位和科室、器械相关性感染和多重耐药菌数据。对新冠疫情前和疫情期间的数据进行比较和分析。结果:共收集疫情前185116名和疫情期间218681名住院患儿的数据。与疫情前相比,疫情期间患儿平均住院天数从6.5天下降至6.1天,NICU、ICU和SICU的平均住院天数增加。住院患儿的感染率从2.7%降至1.79%,呼吸机的使用率从0.9%增加至1.3%,VAP感染率从6.08‰降至2.55‰,中央血管导管使用率从3.42‰增加至13.97‰,均差异显著(P<0.001),CLABSI、住院患儿导尿管的使用率、CAUTI无统计学差异。除ICU多重耐药菌检出率从30%增加至42%,全院多重耐药菌检出率无统计学差异。检出MRSA与CRE占比下降,CRAB与CRPA占比增加。结论:疫情期间各种阻断病毒传播的防控措施使全院住院患儿感染率下降,设备相关的VAP感染率显著降低。医院应继续加强院内感染控制措施,预防可能增加的多重耐药菌的发生。

郑州地区宠物犬体内常见细菌的分离鉴定及药敏试验

为了解宠物犬体内常见细菌种类及其对临床常用抗生素的耐药情况,选取郑州市数家宠物医院对患病犬和健康犬分别进行样本采集。通过分离培养纯化,16S rRNA序列分析鉴定,获得大肠杆菌12株、葡萄球菌8株、肠球菌17株、肺炎克雷伯菌5株及沙门氏菌2株。采用微量肉汤稀释法测定7大类14种抗生素的最小抑菌浓度(MIC值),进行药物敏感性和多重耐药表型分析。结果表明,所有细菌总体对替加环素和黏菌素的敏感性较高,对其它抗菌药物的敏感性因细菌种类不同而产生差异。犬源细菌多重耐药现象较为普遍,本试验菌株的多重耐药率为59%(26/44),其中大肠杆菌、葡萄球菌和肺炎克雷伯菌的多重耐药率分别为19.2%、30.8%和7.7%。本试验初步探明了郑州地区宠物犬源常见细菌的药物敏感性及多重耐药情况,对宠物犬临床应用抗菌药具有指导意义。

污水中红霉素抗性菌的特性

针对抗生素过度使用对生态环境和人类健康造成潜在威胁的问题,采用微生物的分离培养方法和聚合酶链式反应(polymerase chain reaction,PCR)检测方法,对北方某污水处理厂中各个处理单元中红霉素残留浓度、抗性菌、抗性基因的特性进行了翔实的研究。研究结果显示,在污水中检测到红霉素浓度7.5~86.9μg/L,去除率为81.4%~89.3%。进水、出水中残留的红霉素抗性菌(erythromycin antibiotic resistance bacteria,EARB)的浓度分别在6.9×10^(5)~8.4×10^(5)CFU/mL和1.8×10^(5)~3.5×10^(5)CFU/mL。单一红霉素抗性菌比例为45.0%,双重抗生素抗性菌株的比例为40.84%,三重抗生素抗性菌株的比例为14.16%。抗性菌对6种抗生素抗性也表现出不同的抗性,多重抗性菌表现出。抗生素抗性基因(antibiotic resistance genes,ARGs)中浓度在1.3~9.5 lg(copies/L)。1株单一抗性菌未检测到ereA、ereB、mefA/mefE和ermB的基因。在26株磺胺+红霉的抗性菌中,2株未检测到int2,各有1株未检测到int1、ereB。三重抗性菌中,4株未能检测到tetQ,各有2株未能检测到tetX和int2;各有1株未能检测到int1、mefA/mefE、ereB。研究结果表明污水中红霉素残留量高,EARB具有多重抗生素抗性,多重抗性菌未检测到对应的目的ARGs,推测环境中长期残留多种抗生素,游离多重ARGs对抗性菌的演变产生具有重要影响,与抗性菌抗性存在相应的关系。

集雨补灌春马铃薯收后复种夏蚕豆对土壤养分及细菌群落结构的影响

[目的]研究集雨补灌条件下,春马铃薯—夏蚕豆复种(薯豆复种)+豆秆还田对土壤养分变化及细菌群落结构的影响。[方法]以薯豆复种+豆秆还田、马铃薯种后空闲以及马铃薯连作土壤为研究对象,测定土壤理化性质;采用Illumina NovaSeq PE250对土壤细菌16S V3~V4区域进行高通量测序。[结果]与常规栽培模式相比,集雨补灌条件下,春作马铃薯提前75~76 d出苗,提前43~74 d收获,避开了晚疫病危害,滇薯23、滇薯47和青薯9号的产量分别增加28953.0、8571.0和28570.5 kg/hm^(2)。与马铃薯连作相比,薯豆复种+豆秆还田的土壤pH值增加0.17,有机质含量增加0.35%,全氮含量增加0.02%,有效氮含量增加43.6 mg/kg,有效钾含量增加51.5 mg/kg。与马铃薯种后空闲相比,薯豆复种+豆秆还田的土壤pH值增加0.14,有机质含量增加0.33%,全氮含量增加0.02%,全磷含量增加0.02%,有效氮含量增加39.8 mg/kg。薯豆复种+豆秆还田模式下,土壤中放线菌门、芽单胞菌门和鞘氨醇单胞菌属相对丰度高于马铃薯种后空闲模式和连作模式,但连作模式下土壤酸杆菌门丰度更高。相关性分析表明:土壤pH以及全磷和全钾含量是驱动细菌门丰度变化的主要环境因子。[结论]薯豆复种+豆秆还田可提高土壤肥力、减缓土壤酸化、增加土壤有益细菌门和属的相对丰度,而马铃薯连作会降低土壤pH和减少有益细菌;集雨补灌春作马铃薯收后复种夏蚕豆可增加复种指数,提高土地利用效率,改善土壤营养状况和细菌群落结构,减轻马铃薯连作障碍。

Silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes with an enhanced antibacterial activity for killing drug-resistant bacteria

The mounting threat of antibiotic-resistant bacterial infections has made it imperative to develop innovative antibacterial strategies.Here we propose a novel antibacterial nanoplatform of silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes constructed via a N-[3-(trimethoxysiltyl)propyl]ethylene diamine(TSD)-mediated method(SWCNTs@mSiO2-TSD@Ag).In this system,the outer mesoporous silica shells are able to improve the dispersibility of SWCNTs,which will increase their contact area with bacteria cell walls.Meanwhile,the large number of mesopores in silica layers act as microreactors for in situ synthesis of Ag NPs with controlled small size and uniform distribution,which induces an enhanced antibacterial activity.Compared with TSD modified mesoporous silica coated single-walled carbon nanotubes(SWCNTs@mSiO2-TSD)and commercialAg NPs,this combination nanosystem of SWCNTs@mSiO2-TSD@Ag exhibits much stronger antibacterial performance against multi-drug-resistant bacteria Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)in vitro through damaging the bacterial cell membranes and a fast release of silver ions.Furthermore,the in vivo rat skin infection model verifies that SWCNTS@mSiO2-TSD@Ag have remarkably improved abilities of bacterial clearance,wound healing promoting as well as outstanding biocompatibility.Therefore,this novel nanoplatform indicates promising potentials as a safe and powerful tool for the treatment of clinical drug-resistant infections.

2019—2021年甘肃省老年患者临床分离菌分布及耐药性分析

目的分析2019—2021年甘肃省老年患者临床分离菌的分布特点及其耐药性。方法收集甘肃省2019年1月—2021年12月各个医院≥65岁的老年患者临床分离菌,用药敏纸片扩散法、最低抑菌浓度(MIC)法和E试验法测定细菌对抗菌药物敏感性,根据CLSI标准判读结果,采用WHONET 5.6软件分析结果。结果甘肃省2019—2021年≥65岁的老年患者临床分离菌均以革兰阴性菌为主,占比分别为79.4%、80.4%和79%,均以大肠埃希菌的检出率最高,革兰阳性菌中以金黄色葡萄球菌的检出率最高,近3年均在35%左右,其中耐甲氧西林金葡菌(MRSA)的检出率分别为35.2%、37.5%和36%,耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的检出率分别为67.9%、66.8%和71.1%,且MRSA和MRCNS对抗菌药物的耐药率均高于甲氧西林敏感金黄色葡萄球菌(MSSA)和甲氧西林敏感凝固酶阴性葡萄球菌(MSCNS),未发现对万古霉素、替考拉宁耐药的菌株。粪肠球菌近3年检出率呈上升趋势,屎肠球菌的检出率维持在2.5%左右;第三代头孢菌素类耐药的大肠埃希菌的检出率高于肺炎克雷伯菌;铜绿假单胞菌对妥布霉素、多黏菌素B的耐药率有下降趋势,分别从11.5%下降到7.6%,从2.3%下降到1.3%,而对头孢哌酮/舒巴坦的耐药率有上升趋势,鲍曼不动杆菌多各类抗菌药物的耐药率均高于铜绿假单胞菌。结论甘肃省老年患者临床分离病原体以革兰阴性菌为主,耐药现状严重,对老年患者临床病原菌进行耐药性分析,有助于临床为老年患者合理运用抗菌药物,以减少抗菌药物的滥用。

An Exceptional Broad-Spectrum Nanobiocide for Multimodal and Synergistic Inactivation of Drug-Resistant Bacteria

This study reports the fabrication of a novel photothermal material formed via the physical blending of excess lauric acid(LA)and cupric acetate,followed by efficient ligand exchange.Surprisingly,the copper–LA complex exhibited a 12-fold enhancement of the molar extinction coefficient in the nearinfrared(NIR)region relative to aqueous cupric acetate.Inspired by this interesting finding,we formulated these photothermal materials into colloidally dispersed nanoparticles via a technique that combined nanoprecipitation and in situ surface polymerization for antibacterial studies.The resultant nanoparticles exhibited rapid and stable photothermal responses to NIR irradiation,with a 4-fold enhanced photothermal conversion efficiency relative to aqueous cupric acetate.Since a positively charged monomer was incorporated during in situ surface polymerization,these positively charged nanoparticles were ingested efficiently and subsequently digested by drug-resistant bacteria.By combining the LA-mediated membrane-damaging effect,copper-mediated Fenton-like reaction,as well as the photothermal effect of the copper–LA complex,a broad-spectrum,multimodal,and synergistic antibacterial effect was achieved both in vitro and in vivo,with the killing efficiency up to 99.99%for ampicillin-resistant Escherichia coli(Ampr E.coli)and 99.9999%for methicillinresistant Staphylococcus aureus(MRSA).Our newly developed nanobiocide represents a class of exceptional broad-spectrum antibacterial materials,holding great potential for treating drug-resistant infections in clinical settings.

表面增强拉曼光谱技术在多元病原菌同时检测中的应用策略

水、空气、食品、灰尘和排泄物中广泛存在食源性病原菌,由此引发的感染性疾病严重危害人类健康。因此,开发病原菌的快速检测方法尤为必要。由于实际样品中的病原菌往往共生存在,所以多元病原菌的同步灵敏检测是微生物检测领域的重点与难点。分子生物学和免疫组化分析技术都在此领域进行过一些尝试,但由于引物设计与抗体的局限性,这两种技术在实际应用中的效果并不十分理想。表面增强拉曼光谱(SERS)技术由于具有快速、无损、高分辨率、不受水分干扰、可原位检测等显著优势,在多元病原菌同步检测领域获得了重要应用。从应用原理、特点和效果等方面出发,系统阐述了SERS技术在多元病原菌同时检测中的应用策略。首先对SERS基底材料与病原菌的结合方式进行简要概述,再以检测策略为主线,从直接法和间接法两种策略出发进行介绍。直接法通过基底材料的信号放大作用直接获得病原菌本身的光谱信息,步骤简便,操作快捷,在多元病原菌判别分析、定量分析与即时检测(POCT)中被广泛应用。但由于光谱信息量大,往往需要与多元统计分析方法、成像技术和微流控器件等联用。间接法一般需要借助拉曼信号分子和适配体、抗体等识别元件,将对病原菌的检测转换为对信号分子的分析,极大提高了检测方法的灵敏度与特异性,可在基因、蛋白、细胞等水平实现对多元病原菌的同步分析。且与其他识别元件及功能分子的联用能构建得到集细菌的分离、识别与灭活于一体的综合检测体系,在临床血液等实际样本的分析中具有重要前景。最后,总结并指出SERS技术的现有问题及下一步努力方向,为SERS技术在多元病原菌的快速、灵敏检测策略设计及具体应用方面提供参考。

窖池高产己酸菌营养液的制备及培养条件优化

从优质老窖泥中分离出高产酸己酸菌,确定影响己酸生成和己酸菌生长的各因素并通过单因素试验确定最佳发酵条件,温度为35℃、接种量10%、pH6.5~7.5、容积系数90%,在此条件下制备己酸菌液并与老窖池中过滤的混合菌过滤液按照1∶1的比例混合培养作为窖池营养液,通过正交试验确定营养液最佳培养基成分及含量为乙醇浓度1.5%,乙酸钠浓度0.25%,硫酸铵浓度0.05%,磷酸氢二钾浓度0.15%,硫酸镁浓度0.01%,经过7 d无氧发酵培养,己酸产量达到5.7 g/L。本研究为窖池养护液的制备及培养等提供了理论基础。

新生儿重症监护病房多重耐药菌反复感染的危险因素分析

目的探讨新生儿重症监护病房多重耐药菌反复感染的危险因素。方法回顾性分析2018年11月—2021年11月我院收治的100例多重耐药菌感染的新生儿,根据治疗后感染情况分为反复感染组(20例)和非反复感染组(80例)。分析患儿的感染部位和病原菌种类;比较2组患儿的一般资料;多因素Logistic回归分析影响患儿反复感染的危险因素;构建贝叶斯网络模型,并使用Netica软件进行贝叶斯网络推理;采用ROC曲线和校准曲线评价模型的区分度和准确度。结果100例患儿主要以呼吸道感染为主,检测出多重耐药菌菌株共158株,其中革兰阴性菌占75.95%,革兰阳性菌占24.05%。多因素Logistic回归分析结果显示,住院天数≥7 d、机械通气、抗菌药物种类≥3种和抗菌药物使用时间≥7 d是患儿反复感染的独立危险因素,而出生胎龄≥37周、出生体质量≥2500 g是患儿反复感染的保护因素(P<0.05)。ROC曲线和校准曲线显示贝叶斯网络模型具有良好的区分度和准确度。结论临床应对患儿胎龄、出生体质量、住院天数等危险因素进行重点关注,以降低多重耐药菌反复感染的发生率。