Degenerate PCR primers for the amplification of fragments from genes encoding response regulators from a range of pathogenic bacteria

Many bacterial responses to environmental stimuli are mediated by response regulators which coordinately regulate genes involved in particular adaptive responses. Degenerate oligonucleotide primers were used to amplify by the polymerase chain reaction (PCR), fragments from genes encoding eleven novel response regulators. Sequence and phylogenetic analysis revealed that phoB, phoP and creB gene fragments had been amplified from Yersinia enterocolitica and Yersinia pseudotuberculosis, and that a creB sequence had been amplified from Campylobacter jejuni. Four amplified fragments from C. jejuni, Listeria monocytogenes, Mycobacterium tuberculosis and Escherichia coli clearly came from response regulator genes, but were not closely related to any of the known genes. Mutagenesis of the newly identified genes should allow us to determine their function and the genes under their control.     

支气管扩张合并支气管哮喘患者支气管肺泡灌洗液病原菌培养及药敏状况研究

目的:对支气管扩张合并支气管哮喘患者支气管肺泡灌洗液病原菌培养及药敏状况展开分析,实现多药耐药医院感染的有效预防与控制。方法:随机选取2010年9月~2013年8月期间收治的50例支气管扩张症合并支气管哮喘患者,对50例患者支气管肺泡灌洗液标本进行病原学检测及药敏试验,并对临床感染资料及病原菌耐药性进行统计学分析。结果:50例支气管扩张症合并支气管哮喘患者支气管肺泡灌洗液培养阳性率为30例,60.0%,共分离出48株细菌。其中,革兰阳性球菌5株,占分离菌的10.4%;革兰阴性杆菌41株,占分离菌的85.4%;真菌2株,占分离菌的4.2%。41株革兰阴性杆菌对抗菌药物的耐药性分别为:复方新诺明73.1%,阿米卡星22.0%,环丙沙星14.6%,头孢曲松48.8%,头孢噻肟41.5%,头孢哌酮19.5%,头孢他啶20.7%,头孢他啶/舒巴坦12.1%,头孢吡肟22.0%,庆大霉素17.1%,阿莫西林/克拉维酸41.5%,哌拉西林/他唑巴坦19.5%。结论:铜绿假单胞菌是支气管扩张合并哮喘患者感染中的常见病原菌,医务人员要结合病原菌高耐药率、高分离阳性率的特征,合理运用抗菌药物控制传播。     

伤口感染病原菌分布及耐药谱分析

目的探讨创伤患者伤口感染的常见病原菌及其耐药性,指导临床合理用药。方法回顾分析2010年至2012年创伤患者感染伤口分泌物的细菌分离培养及体外药物敏感试验,对感染的主要病原菌及耐药性进行分析。结果分离到细菌1086株,居于感染首位的是金黄色葡萄球菌（23．6％）,其次是大肠埃希菌（23．2％）,肺炎克雷伯菌（10．2％）,鲍曼不动杆菌（8．8％）,铜绿假单胞菌（6．6％）,分离到8株白色假丝酵母菌（0．7％）;耐甲氧西林金黄色葡萄球菌（metieillin—multiple resistance S．attrelts,MRSA）检出率为71．5％,MRSA除对万古霉素、利奈唑胺100％敏感外,对其他常用抗菌药物均存在较高的耐药性,与MRSA的耐药性明显高于MSSA（P〈0．01）。产超广谱B一内酰胺酶菌株（extended—spectrumbeta—lactamase,ESBLs）的检出率为64．5％,除碳青霉烯类抗菌药物外,ESBLs对喹诺酮类、氨基糖甙类等的常用抗菌药物存在较高的耐药率;其耐药率远高于非ESBLs（P〈0．01）;多重耐药的铜绿假单胞菌（multi—drug resistant Pesudomonas aeruginosa,MDRPA）检出率为40．3％（29／72）,耐碳青霉烯的鲍曼不动杆菌（Carbapenems—resistant Acineto—bacterbaumannii,CA—Ab）的检出率为43．2％（41／95）。仅头孢哌酮／舒巴坦及阿米卡星有良好的敏感性（〉50％）,而对其余绝大部分常用抗菌药物的耐药性相当严重。结论伤口感染以革兰阳性球菌为主,感染病原菌多为多重／泛耐药菌株,对常用抗菌药物甚至碳青霉烯类耐药性严重,应该引起高度重视,临床应据细菌药物敏感性试验报告选用抗菌药物。     

An assessment of pathogen removal during composting of the separated solid fraction of pig manure

The aim was to investigate pathogen survival during composting of pig manure solids with and without bulking agents in two trials of 56 days duration, each with four treatments. Salmonella was detected in the sawdust and straw bulking agents but was undetectable in the compost, except in one treatment at day 0. Enteric indicator organisms were reduced by day 7 (P<0.001) and were undetectable in the final compost, except for coliform which were present at 3.66-4.43 log?? CFU/g. Yeasts and moulds were reduced and aerobic spore-formers remained stable in one trial but both increased in the other (P<0.001). Bacillus licheniformis and Clostridium sporogenes were the predominant culturable spore-forming bacteria recovered. Microbial counts were influenced by the bulking agent but only at particular time points (P<0.05). Overall, the pig manure-derived compost complied with EU regulations for processed manure products, as E. coli and Enterococcus were below limits and it was Salmonella-free.     

Virulence Factors Produced by Staphylococcus aureus Biofilms Have a Moonlighting Function Contributing to Biofilm Integrity

1. Download : Download high-res image (137KB)
2. Download : Download full-size image

Highlights

• •Establishment of a flow system allowing multi-omics analysis of S. aureus biofilms.
• •Biofilm proteome profiling (intracellular and ECM) plus metabolic footprint analysis.
• •Virulence factors and ribosomal proteins stabilize the ECM as moonlighting proteins.
• •They act as electrostatic bridges between anionic cell surfaces, eDNA and metabolites.

     

致病微生物应对环境胁迫形成的VBNC状态及其对风险评估的潜在影响

防止食源性致病菌对食品的污染是保障食品安全的重要策略之一。研究表明,环境胁迫下微生物可能形成"活的不可培养状态"(VBNC状态),成为食品安全的潜在风险。本文对致病微生物VBNC状态的最近发现进行了归纳和总结,重点分析了不同环境胁迫(包括自然胁迫以及食品加工和保藏过程中的各种胁迫等)因素下菌体进入VBNC状态的普遍性、诱导条件和生理特点等,并对现行的基于微生物可培养性而建立起来的常规检测方法的局限性及其对食品安全风险评估潜在影响进行了讨论。     

Biological control of arthropod pests in citrus orchards in China

China has a very long history of biological control in citrus. Hundreds years ago, predatory ants (Oecophylla smaragdina Fabricius) were used to manage pests by Chinese citrus growers. Considerable effort has been placed on the use of biological control in citrus plant landscapes during last three decades. Many scientific studies have now been published, and some additional implementations have already working. In this paper, we review the research, development and application of biological control of citrus insect pests in China. In addition, the importance of biological control for the future control of citrus insect pests is also discussed.     

Polyphenol oxidases in plants and fungi: going places? A review

The more recent reports on polyphenol oxidase in plants and fungi are reviewed. The main aspects considered are the structure, distribution, location and properties of polyphenol oxidase (PPO) as well as newly discovered inhibitors of the enzyme. Particular stress is given to the possible function of the enzyme. The cloning and characterization of a large number of PPOs is surveyed. Although the active site of the enzyme is conserved, the amino acid sequence shows very considerable variability among species. Most plants and fungi PPO have multiple forms of PPO. Expression of the genes coding for the enzyme is tissue specific and also developmentally controlled. Many inhibitors of PPO have been described, which belong to very diverse chemical structures; however, their usefulness for controlling PPO activity remains in doubt. The function of PPO still remains enigmatic. In plants the positive correlation between levels of PPO and the resistance to pathogens and herbivores is frequently observed, but convincing proof of a causal relationship, in most cases, still has not been published. Evidence for the induction of PPO in plants, particularly under conditions of stress and pathogen attack is considered, including the role of jasmonate in the induction process. A clear role of PPO in a least two biosynthetic processes has been clearly demonstrated. In both cases a very high degree of substrate specificity has been found. In fungi, the function of PPO is probably different from that in plants, but there is some evidence indicating that here too PPO has a role in defense against pathogens. PPO also may be a pathogenic factor during the attack of fungi on other organisms. Although many details about structure and probably function of PPO have been revealed in the period reviewed, some of the basic questions raised over the years remain to be answered.     

Potential role of natural enemies during tree range expansions following climate change

Recent investigations have shown how chance, long-range dispersal events can allow tree populations to migrate rapidly in response to changes in climate. However, this apparent solution to Reid's paradox applies solely within the context of single species models, while the rapid migration rates seen in pollen records occurred within multispecies communities. Ecologists are therefore presented with a new challenge: reconciling the macroscopic dynamics of spread seen in the pollen record with the rules and interactions governing plant community assembly. A case that highlights this issue is the rapid spread of Beech during the Holocene into a landscape already dominated by a close competitor, Hemlock. In this study, we analyse a simple model of plant community assembly incorporating competition for space and dispersal dynamics, showing how, even when a species is capable of rapid migration into an empty landscape, the presence of an ecologically similar competitor causes Reid's paradox to re-emerge because of the dramatic slowing effect of competitive interactions on a species' rate of spread. We then show how the answer to the question of how tree species dispersed rapidly into occupied landscapes may lie in secondary interactions with host-specific pathogens and parasites. Inclusion of host-specific pathogens into the simple community assembly model illustrates how tree species undergoing range expansions can temporarily outstrip specialist predators, giving rise to a transient Jansen-Connell effect, in which the invader acts as temporary 'super-species' that spreads rapidly into communities already occupied by competitors at rates consistent with those observed in the paleo-record.