Comparative analysis of Bombyx mori nucleopolyhedrovirus responsive genes in fat body and haemocyte of B. mori resistant and susceptible strains

The infection profiles of the Bombyx mori nucleopolyhedrovirus (BmNPV) in B. mori larvae revealed that the virus invaded the fat body and haemocyte of both KN and 306 strains, which are highly resistant and susceptible, respectively, to BmNPV infection. However, viral proliferation was notably slowed in the resistant B. mori strain. Using suppression subtractive hybridization, two fat body cDNA libraries were constructed to compare BmNPV responsive gene expression levels between the two silkworm lines. In total, 96 differentially expressed genes were obtained. Real‐time quantitative PCR (qPCR) analysis confirmed that eight genes were significantly up‐regulated in the fat body and haemocyte of the KN strain following BmNPV injection. Our results suggest that these genes may have potential roles in B. mori antiviral infection mechanisms.     

医院内感染碳青霉烯类耐药鲍曼不动杆菌的耐药基因及同源性分析

目的分析引起院内感染的碳青霉烯类耐药鲍曼不动杆菌(CRAB)耐药基因及同源性。方法收集CRAB 40株,采用琼脂稀释法检测最低抑菌浓度(MIC);PCR检测主要的碳青霉烯酶基因,PCR产物进行DNA测序分析;肠杆菌科基因间重复一致性序列聚合酶链反应(ERIC-PCR)对耐药菌株进行基因分型及同源性分析,质粒接合试验探讨耐药基因的可传递性。结果40株CRAB仅对多黏菌素B(100%)和头孢哌酮/舒巴坦保持良好的敏感性(57.5%),对其他药物均产生不同程度耐药;全部菌株均检测出OXA-23和OXA-51基因;同源性分析显示,按80%的聚类相似系数可将40株菌株分为4个型,A1型为主要流行株(19株),且各科室存在交叉感染;质粒接合试验未获成功。结论该院存在CRAB的流行传播,其耐药机制主要与OXA-23基因的表达有关;在合理使用抗菌药物的同时,应做好隔离及防护措施,尽量避免医院内交叉感染。     

17株耐亚胺培南肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学分析

目的了解17株亚胺培南耐药肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学状况。方法采用Hodge试验检测碳青霉烯酶表型;采用PCR法检测碳青霉烯酶、I类头孢菌素酶(AmpC)和超广谱β-内酰胺酶(ESBLs)耐药基因,进行测序及网上比对确定基因型;采用肠杆菌科基因间重复序列(ERIC)和多位点序列分型(MLST)对菌株进行同源性和遗传相关性分析。结果 15株肺炎克雷伯菌检出KPC-2、TEM-1、SHV和CTX-M型基因,SHV12和CTX-M-24为主要基因亚型;2株大肠埃希菌检出KPC-2基因,其中1株大肠埃希菌检出TEM-1和CTX-M-24基因,另一株大肠埃希菌检出CMY-42和OXA-1基因;17株菌未检测到IMP、VIM和NDM碳青霉烯酶。15株肺炎克雷伯菌分为A、B和C三个ERIC类别,12株A类为ST11型,2株B类为ST290和ST147型,1株C类为ST967型,2株大肠埃希菌是同一ERIC类别。结论 17株菌亚胺培南耐药主要与KPC-2基因有关,产KPC-2肺炎克雷伯菌在本院神经外科病区呈克隆传播流行,ST11型为此次流行的主要型别;17株菌同时也是产ESBLs株或产ApmC酶株;首次在世界范围内发现ST290和ST967型产KPC-2肺炎克雷伯菌;临床科室应加强院内感染控制措施。     

Multiple Influenza A (H3N2) Mutations Conferring Resistance to Neuraminidase Inhibitors in a Bone Marrow Transplant Recipient

Immunocompromised patients are predisposed to infections caused by influenza virus. Influenza virus may produce considerable morbidity, including protracted illness and prolonged viral shedding in these patients, thus prompting higher doses and prolonged courses of antiviral therapy. This approach may promote the emergence of resistant strains. Characterization of neuraminidase (NA) inhibitor (NAI)-resistant strains of influenza A virus is essential for documenting causes of resistance. In this study, using quantitative real-time PCR along with conventional Sanger sequencing, we identified an NAI-resistant strain of influenza A (H3N2) virus in an immunocompromised patient. In-depth analysis by deep gene sequencing revealed that various known markers of antiviral resistance, including transient R292K and Q136K substitutions and a sustained E119K (N2 numbering) substitution in the NA protein emerged during prolonged antiviral therapy. In addition, a combination of a 4-amino-acid deletion at residues 245 to 248 (Δ245-248) accompanied by the E119V substitution occurred, causing resistance to or reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir). Resistant variants within a pool of viral quasispecies arose during combined antiviral treatment. More research is needed to understand the interplay of drug resistance mutations, viral fitness, and transmission.     

Comparative proteome analysis of silkworm in its susceptibility and resistance responses to Bombyx mori densonucleosis virus

Bombyx mori densonucleosis virus (BmDNV) is one of the most disastrous viruses in cocoon production. Silkworm resistance to BmDNV has been examined previously using a number of traditional biochemical and molecular techniques. In this study, a near isogenic line, BC(6), was constructed to eliminate the difference in inherited background, which has 99.9% identity with the susceptible strain but carries a resistant gene. We utilized a proteomic approach involving two-dimensional differential gel electrophoresis and mass spectrometry to examine changes in the midgut proteins from the susceptible and resistant silkworm larvae infected with BmDNV. The protein profiles were compared and 9 differentially expressed proteins were identified by mass spectrometry. In the resistant strains, the heat-shock 70-kDa protein cognate, cytochrome P450, vacuolar ATP synthase subunit B, arginine kinase, vacuolar ATP synthase subunit D and glutathione S-transferase sigma were strongly upregulated and α-tubulin was downregulated. Our results imply that these upregulated genes and the downregulated genes might be involved in B. mori immune responses against BmDNV-Z infection.     

多重耐药鲍曼不动杆菌中耐消毒剂基因qacE△1的存在现状及其阳性菌株的同源性分析

目的探讨分析多重耐药鲍曼不动杆菌中耐消毒剂基因qacE△1的存在现状及其阳性菌株的同源性。方法对80株多重耐药鲍曼不动杆菌采用聚合酶链反应和序列分析方法分析其耐消毒剂基因qacE△1,然后采用重复序列聚合酶链反应技术分析qacE△1基因阳性菌株的同源性。结果本研究中,80株多重耐药鲍曼不动杆菌检测阳性42株,阳性率为52.5%,其中A型30株,B型5株,C型3株,D型2株,E型2株,可见A型为主要流行类型,所占比例为71.43%。42株阳性多重耐药鲍曼不动杆菌中,心胸外科为8株,约占19%,神经外科7株,约占17%,中心重症监护病房(ICU)6株,约占14%。当最小抑菌浓度(MIC)为300mg/L时,抑制菌株量最多,当MIC为500mg/L时,抑制菌株中阳性菌株所占比例最高,为83.33%。结论多重耐药鲍曼不动杆菌的耐药性增强与耐消毒剂基因qacE△1具有相关性,且在临床上存在5种分型,主要为A型,心胸外科、神经外科和中心ICU应该作为主要感染控制对象。     

高毒力肺炎克雷伯菌中CRISPR-Cas系统的分布及其与毒力和耐药的关系

目的了解高毒力肺炎克雷伯菌中CRISPR-Cas系统的分布特征,并探究其与毒力和耐药的关系。方法收集非重复高毒力肺炎克雷伯菌61株,使用VITEK 2-Compact全自动微生物分析系统进行菌株鉴定及药物敏感性分析,PCR检测CRISPR-Cas系统4个相关基因(Cas1、Cas3、CRISPR1和CRISPR2)、筛查荚膜血清分型基因K1/K2、14种毒力基因及14种耐药基因,用χ2检验比较CRISPR-Cas系统阳性菌株与阴性菌株毒力基因及耐药差异。大蜡螟毒力实验分析比较两组细菌的毒力差异,并且采用多位点序列分型(MLST)分析所有高毒力肺炎克雷伯菌分子分型与CRISPR-Cas系统的关系。结果CRISPR-Cas系统阳性检出率为34.4%(21/61),所有CRISPR-Cas系统阳性的菌株均为ST23型K1菌株,除毒力基因kpn、repA外,CRISPR-Cas系统阳性的高毒力肺炎克雷伯菌携带毒力基因阳性率均大于对应的阴性菌,其中5种毒力基因差异具有显著统计学意义。除耐药基因blaNDM-1、qnrB外,CRISPR-Cas系统阳性高毒力肺炎克雷伯菌的8种耐药基因阳性率均小于对应的阴性菌株,差异具有显著统计学意义。CRISPR-Cas系统阳性高毒力肺炎克雷伯菌感染大蜡螟平均半数生存时间少于对应的阴性菌感染,差异具有统计学意义。MLST结果表明高毒力肺炎克雷伯菌CRISPR-Cas系统分布与分型密切相关。结论CRISPR-Cas系统阳性高毒力肺炎克雷伯菌主要为ST23型K1菌株,CRISPR-Cas系统阳性肺炎克雷伯菌相对于阴性菌株的毒力强,毒力基因阳性率高,耐药率低,耐药基因的阳性率低。临床上应警惕CRISPR-Cas系统阴性ST11型“碳青霉烯类耐药高毒力肺炎克雷伯菌”的暴发,此类细菌进化获得毒力质粒pLVPK毒力强、高度耐药、传播性强,可能成为危害公共健康并难以控制的超级细菌。     

86株鲍曼不动杆菌碳青霉烯酶耐药基因分析及同源性研究

目的分析北京康复医院住院患者分离的耐碳青霉烯类鲍曼不动杆菌的分布特点、耐药性及同源性。方法收集2017年12月至2018年12月北京康复医院临床感染病例中非重复分离的86株耐碳青霉烯类鲍曼不动杆菌,采用Phoenix BD 100进行菌株鉴定和药敏试验。采用基因组重测序技术检测其携带的耐药相关基因并进行进化树分析,采用多位点序列分型分析菌株间的同源性。结果86株耐碳青霉烯类鲍曼不动杆菌均表现为多重耐药。共检出17种耐药基因,全部菌株均携带OXA-23型碳青霉烯酶耐药基因;检出多种β内酰胺酶基因、外排泵相关基因、抗菌药物修饰酶基因等。多位点序列分型得到15种ST型,同源性分析提示部分菌株间存在较近亲缘关系。结论北京康复医院鲍曼不动杆菌耐药情况严重,OXA-23为主要耐药基因型,菌株之间存在同源相关性,应加强医院感染防控。     

重症医学科血流感染耐碳青霉烯类高黏液型肺炎克雷伯菌的临床及分子特征

目的分析医院重症医学科(ICU)血流感染患者检出的耐碳青霉烯类高黏液型肺炎克雷伯菌(CR-HMKP)的临床及分子特征。方法2016年1月-2018年12月从ICU血流感染患者中分离40株耐碳青霉烯类肺炎克雷伯菌(CR-KP),通过拉丝试验分为14株CR-HMKP菌和26株CR-非HMKP菌,分析菌株的临床和药敏资料,采用PCR检测菌株的耐药基因、毒力基因及血清荚膜分型,多位点序列分型(MLST)和脉冲场凝胶电泳(PFGE)方法分析细菌的分子流行病学特征。结果CR-HMKP在CR-KP中的检出率为35.0%。CR-KP感染患者均接受两种或两种以上侵袭性操作和联合使用多种抗生素。CR-HMKP菌株感染患者60岁以上的占比、糖尿病患病率、死亡率比CR-非HMKP菌株感染患者高,且差异有统计学意义(P<0.05)。CR-KP菌株均为多重耐药(MDR)菌,CR-HMKP菌株对庆大霉素、妥布霉素、阿米卡星的耐药率比CR-非HMKP菌株低,且差异有统计学意义(P<0.05)。碳青霉烯酶基因以KPC为主(95.0%),rmtB基因在CR-HMKP菌株的检出率小于CR-非HMKP菌株,且差异有统计学意义(P<0.01)。CR-HMKP菌株中仅检出1株K2型菌株,rmpA、iutA、rmpA2三种毒力基因在CR-HMKP菌株的检出率均大于CR-非HMKP菌株,且差异有统计学意义(P<0.01)。PFGE和MLST显示CR-HMKP分为A、B型,A型(n=13,92.9%)均为ST11型,B型(n=1,7.1%)为ST65型。结论ICU血流感染患者分离的CR-HMKP菌株以ST11型为主,均为MDR菌,携带多种耐药基因与毒力基因,且患者死亡率高,应加强防控。CRHMKP与CR-非HMKP对氨基糖苷类抗生素的耐药情况有差别,临床在治疗过程中应区别对待。     

Friend murine leukemia virus-induced leukemia is associated with the formation of mink cell focus-inducing viruses and is blocked in mice expressing endogenous mink cell focus-inducing xenotropic viral envelope genes

In these studies, we have shown data that are consistent with the hypothesis that mink cell focus-inducing viruses (MCF) play an important role in the generation of an erythroproliferative disease developing after injection of certain strains of newborn mice with ecotropic Friend murine leukemia virus (F-MuLV). Resistance to this disease is correlated with the endogenous expression of an MCF/xenotropic virus-gp70-related protein that may interfere with the replication or spread of MCF viruses. These ideas are supported by the following observations: (a) after infection with F-MuLV, only 6/13 strains of mice-developed disease, and studies with crosses between susceptible and resistant strains indicated that resistance was dominant. Although F-MuLV was shown to replicate equally well in all strains tested, viruses coding for MCF-specific viral envelope proteins could be detected only in the spleens of mice from strains that were resistant to F-MuLV-induced disease and not in the spleens of mice from strains that were resistant to F-MuLV-induced disease; (b) a Friend MCF (Fr-MCF) virus isolated from the spleen of an F-MuLV-infected mouse from a susceptible strain induced the same erythroproliferative disease when injected as an appropriate pseudotype into mice from susceptible but not resistant strains of mice; and (c) resistant but not susceptible strains of mice endogenously express MCF/xenotropic virus- related envelope glycoproteins that may be responsible for resistance by blocking receptors for MCF viruses. These results not only indicate that Fr-MCF virus is a crucial intermediate in the induction of disease by F-MuLV, but also suggest that a novel gene, either an MCF/xenotropic virus-related envelope gene or a gene controlling its expression, is responsible for resistance to erythroleukemia induced by F-MuLV.     

The role of G protein‐coupled receptor‐related genes in cytochrome P450‐mediated resistance of the house fly,Musca domestica (Diptera: Muscidae), to imidacloprid

Ninety‐four putative G protein‐coupled receptors (GPCRs) were identified in the Musca domestica genome. They were annotated and compared with their homologues in Drosophila melanogaster. Phylogenetic analyses of the GPCRs from both species revealed that several family members shared a closer relationship based on the domain architecture. The expression profiles of these genes were examined by quantitative real‐time PCR amongst three strains of the house fly, a near‐isogenic line strain with imidacloprid resistance (N‐IRS), the corresponding susceptible strain (CSS) and another strain derived from field populations with imidacloprid resistance (IRS). We found that five GPCR genes were upregulated in the N‐IRS and eight GPCR genes were upregulated in the IRS strains compared to the CSS strain. The transgenic lines of D. melanogaster with the GPCR genes (LOC101899380 in the N‐IRS strain and LOC101895664 in the IRS strain) exhibited significantly increased tolerance to imidacloprid, and higher expression of cytochrome P450 genes. Bioinformatic analysis of LOC101899380 was carried out based on its full‐length nucleic acid sequence and putative amino acid sequence, and it was named Methuselah‐like10 (Mthl10) owing to its homology with D. melanogaster Mthl10. A cell‐base cell counting kit‐8 toxicity assay demonstrated that the expression of the GPCR gene LOC101899380 in Spodoptera frugiperda (Sf9) cells using a baculovirus‐mediated expression system can elevate the cell tolerance to imidacloprid, indirectly supporting the hypothesis that the GPCR gene LOC101899380 plays some role in imidacloprid resistance. These results should be useful for furthering understanding of the regulatory pathway by which house flies develop resistance.     

Cytochrome P450 CYP4DE1 and CYP6CW3v2 contribute to ethiprole resistance in Laodelphax striatellus (Fallén)

Laodelphax striatellus Fallén (Hemiptera: Delphacidae), a destructive pest of rice, has developed high resistance to multiple insecticides, threatening the success of pest management programmes. The present study investigated ethiprole resistance mechanisms in a field population that is highly resistant to ethiprole. That population was used to establish a laboratory population that was subjected to further selection to produce a resistant strain. Target genes were cloned and compared between the resistant and the susceptible strains, the role of detoxification enzymes was examined, and the relative expression levels of 71 detoxification enzyme genes were tested using quantitative real time (RT)‐PCR. The laboratory selection enhanced the resistance from 107‐fold to 180‐fold. The Rdl‐type target site mutation seldom occurred in the resistant strain and is unlikely to represent the major mechanism underlying the observed resistance. Of the three important detoxification enzymes, only P450 monooxygenase was found to be associated with ethiprole resistance. Moreover, two genes, CYP4DE1 and CYP6CW3v2, were found to be overexpressed in the resistant strain. Furthermore, gene‐silencing via a double‐stranded RNA feeding test was carried out, and the results showed that the mRNA levels of CYP4DE1 and CYP6CW3v2 were reduced in the resistant strain, whereas ethiprole susceptibility was increased. These results suggest that CYP4DE1 and CYP6CW3v2 play an important role in ethiprole resistance in L. striatellus.     

2014－2015年云南省文山州HIV-1毒株耐药基因变异研究

目的：了解2014－2015年云南省文山州免费抗病毒治疗获得性免疫缺陷综合征（简称艾滋病）感染者和艾滋病患者HIV-1基因型耐药发生情况及特点。方法收集文山州2014－2015年接受免费抗病毒治疗的艾滋病患者的临床及实验室资料,对抗病毒治疗持续6个月以上、病毒载量仍大于1000 copies／mL的患者进行基因型耐药检测,分析耐药发生情况及耐药毒株流行特点。结果2014－2015年共计176例艾滋病患者发生病毒学失败,共检测基因型耐药176人次,获得可用序列137条。该人群中耐药发生率为62．0％（85／137）。在使用过的药物中,对奈韦拉平（NVP）、依非韦仑（EFV）高度耐药的有62（45．3％）、50（36．5％）;对拉米夫定（3TC）、替诺福韦（TDF）、司他夫定（D4T）、齐多夫定（AZT）高度耐药的情况分别是31（22．6％）、12（8．8％）、8（5．8％）、2（1．5％）,对蛋白酶抑制剂（PI）没有出现高度耐药的情况。耐药突变与PI 相关的主要耐药基因突变位点有3例,占2．2％（3／137）;M46IM、T74S和L33I各1例。与核苷类反转录酶抑制剂（NRTI）相关的突变中,突变位点发生频率最高的是 M184V／I,为23．4％（32／137）。与非核苷类反转录酶抑制剂（NNRTI）的突变中,突变位点发生频率最高的是K103N／S,为27％（34／137）。137条完整基因序列中,主要为 CRF08 BC 亚型,共67例（48．9％）;其次是 CRF01 AE 亚型,共49例（35．8％）;CRF07 BC亚型有6例（4．4％）;另外还有15例（10．9％）URFs。结论当前文山州的耐药发生率在增加,毒株正变得复杂化,重组毒株在逐渐增加,应加强监测,防止耐药毒株的传播。     

耐亚胺培南鲍曼不动杆菌耐药表型和碳青霉烯酶基因型分析

目的检测广州市第一人民医院20株耐亚胺培南鲍曼不动杆菌的耐药性,研究并分型其碳青霉烯酶基因。方法用法国生物梅里埃公司VITEK2全自动细菌鉴定仪进行菌株鉴定和药敏试验,用6种碳青霉烯酶特异性基因引物进行PCR扩增和基因型的测序分析,并通过网上GenBank进行比对以确定编码酶基因的类型。结果 20株鲍曼不动杆菌对哌拉西林-他唑巴坦、左氧氟沙星和阿米卡星的耐药率分别为85%、50%和25%。对其他所测抗菌药的耐药率均在90%以上。扩增结果显示17株(85%)细菌携带碳青霉烯酶OXA-23基因,16株(80%)携带OXA-51基因,1株(5%)携带OXA 58基因。OXA-24、VIM、IMP基因引物PCR扩增均为阴性,随机抽取OXA-23基因阳性株进行双向测序后在网上GenBank比对与OXA-23标准株99%同源,OXA-51基因阳性株与OXA-66标准株99%同源,OXA-58基因阳性株与OXA-58标准株99%同源。结论我院耐碳青霉烯类抗生素的鲍曼不动杆菌呈现出多重耐药现象,对阿米卡星的耐药率最低,OXA-23型碳青霉烯酶基因检出率最高,OXA-23/OXA-51类基因占60%,应引起临床高度重视,防止在医院内广泛传播。     

Chromosomally mediated beta-lactamase production and gentamicin resistance in Enterococcus faecalis.

We have analyzed four distinct strains of multiply resistant, beta-lactamase-producing enterococci isolated during an outbreak of colonization with these strains on an infant-toddler surgical ward at The Children's Hospital in Boston, Mass. All four strains were resistant to erythromycin, penicillin, and tetracycline and to high levels of gentamicin and streptomycin. One strain was also resistant to chloramphenicol. Plasmid profiles revealed four different plasmid patterns, with the number of identified plasmids ranging from zero to three. The gene coding for beta-lactamase production could be transferred at low frequency (less than 10(-8)) to an enterococcal recipient from one strain in conjunction with all of the other resistance determinants. Probes derived from the staphylococcal beta-lactamase gene and gentamicin resistance gene failed to hybridize with any of the detectable plasmids, but both genes were present on restriction fragments of genomic DNA in all strains. Our results indicate that the beta-lactamase genes and gentamicin resistance genes in these strains are integrated into the bacterial chromosome. The cotransmissibility of the resistance determinants raises the possibility of their incorporation into a multiresistance transposable genetic element.     

枣阳地区外伤患者术后院内多重耐药菌株混合感染的检验分析

目的分析枣阳地区外伤患者术后院内多重耐药菌株混合感染的病原菌分布及抗菌药物耐药情况,为临床治疗提供参考。方法选取合并多重耐药菌株混合院内感染的外伤患者71例,根据感染部位不同取标本进行细菌培养和耐药性分析,并对结果进行统计。结果 71例多重耐药菌株混合感染患者共分离得到多重耐药菌株205株。其中革兰阴性菌检出119株(58.05%),革兰阳性菌检出83株(40.49%),真菌检出3株(1.46%)。大肠埃希菌、肺炎克雷伯菌、肠杆菌、沙雷菌均对10种以上抗菌药物的耐药性超过50%,其中对氨苄西林、头孢噻吩、头孢呋辛、阿洛西林、头孢噻肟、头孢哌酮的耐药率均超过80%。而对亚胺培南以及阿米卡星的耐药性则分别仅有5.88%和28.57%。以金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌、肺炎链球菌为代表的革兰阳性菌对青霉素G、苯唑西林、氨苄西林的耐药率分别为98.80%、97.59%、95.18%。没有革兰阳性菌对万古霉素耐药,此外对利福平、氯霉素的耐药率也分别仅为32.53%和34.94%。结论在感染早期,尚不能明确致病微生物的种类时也难以选择敏感的抗菌药物,在这种情况下联合应用亚胺培南及万古霉素是不错的选择。