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为了鉴定小熊猫（Ailurus fulgens）肺源致病菌并研究其耐药性和耐药基因，从死亡小熊猫肺部组织中无菌分离培养致病菌，进行革兰氏染色及16S rDNA测序鉴定。采用纸片扩散法（KB法）进行细菌药敏试验和小鼠致病性试验，应用PCR法检测分离株的28种β内酰胺酶相关基因、6种氨基糖苷类修饰酶基因（AMEs）、外膜蛋白D2基因（oprD2）、磺胺耐药基因（qacE△1sul1）、3种整合子基因（intⅠ1、2、3）和主动外排泵调节基因（mexR）等共40种耐药基因。肺组织样品中分离培养的1株菌鉴定为铜绿假单胞菌，革兰氏染色阴性，药敏试验对氯霉素敏感，对β内酰胺类、头孢类、氨基糖甙类、大环内酯类、硝基咪唑类、喹诺酮类和利福霉素等均具有耐药性，小鼠表现与小熊猫相似的症状而死亡。5种耐药基因TEM、aac（3）Ⅱ、ant（3″）Ⅰ、qacE△1sul1、intⅠ1为阳性，其他35种为阴性。该小熊猫肺源铜绿假单胞菌具有较强的致病性和多药耐药性，其耐药机制与5种耐药基因有关。

目的研究铜绿假单胞菌野生株（PAO1）及其密度感应（QS）系统基因las R/rhl R缺失株（Δlas RΔrhl R）生物膜感染对气管插管模型鼠肺组织Foxp3、转化生长因子β_1（TGF-β_1）、白细胞介素10（IL-10）表达的影响。方法 21只SD大鼠随机均分为3组（n=7）：PAO1组、Δlas RΔrhl R组及无菌对照组。体外培养生物膜（BF）并经导管置入气管,7d后行肺组织HE染色及肺部组织匀浆菌落计数（cfu）,并检测支气管肺泡灌洗液（BALF）中IL-10、肺组织TGF-β_1、肺组织细胞Foxp3 m RNA表达情况。结果 PAO1组、Δlas RΔrhl R组肺组织均培养出细菌（cfu分别为10 400.00±6313.70、975.00±559.97/g肺组织）,显著高于无菌对照组（未培养出细菌,P〈0.05）,且PAO1组肺部细菌量明显高于Δlas RΔrhl R组（P〈0.05）;肺组织HE染色结果显示：无菌对照组局部轻微充血,无明显炎症改变;PAO1组血管及支气管周围大量炎症细胞浸润,肺泡间隔增宽,局部脓肿、坏死;Δlas RΔrhl R组肺组织病理改变较PAO1组减轻。PAO1组、Δlas RΔrhl R组IL-10含量（分别为188.07±57.01ng/ml、93.31±17.26ng/ml）明显高于无菌对照组（57.43±22.13ng/ml）,且PAO1组明显高于Δlas RΔrhl R组（P〈0.05）。PAO1组、Δlas RΔrhl R组TGF-β_1累积光密度值明显高于无菌对照组,且PAO1组明显高于Δlas RΔrhl R组（P〈0.05）。PAO1组、Δlas RΔrhl R组Foxp3 m RNA表达量（分别为4.62±1.07、2.15±1.43）明显高于无菌对照组（0.65±0.32）,且PAO1组明显高于Δlas RΔrhl R组（P〈0.05）。结论铜绿假单胞菌QS系统las R/rhl R基因可促进铜绿假单胞菌生物膜引起的气管插管模型大鼠的炎症反应,促进肺组织Foxp3表达上调,伴随TGF-β_1、IL-10分泌增多,促使感染迁延化和慢性化。

Clustered regularly interspaced short palindromic repeats （CRISPR） and their associated genes （cas） are essential components of an adaptive immune system that protects bacteria and archaea from viral infection. Now a recent paper published in Cell Research suggests that the Type I-F immune system in Pseudomonas aeruginosa may also be involved in post-transcriptional regulation of virulence.

Objective： To review the origin, diagnosis, treatment and public health concern of New Delhi metallo-β-lactamase （NDM）-producing bacteria. Data Sources： We searched database for studies published in English. The database of PubMed from 2007 to 2015 was used to conduct a search using the keyword term ＂NDM and Acinetobacter or Enterobacteriaceae or Pseudomonas aeruginosa.＂ Study Selection： We collected data including the relevant articles on international transmission, testing methods and treatment strategies of NDM-positive bacteria. Worldwide NDM cases were reviewed based on 22 case reports. Results： The first documented case of infection caused by bacteria producing NDM- 1 occurred in India, in 2008. Since then, 13 blaNDM variants have been reported. The rise of NDM is not only due to its high rate of genetic transfer among unrelated bacterial species, but also to human factors such as travel, sanitation and food production and preparation. With limited treatment options, scientists try to improve available therapies and create new ones. Conclusions： In order to slow down the spread of these NDM-positive bacteria, a series of measures must be implemented. The creation and transmission of blaNDM are potentially global health issues, which are not issues for one country or one medical community, but for global priorities in general and for individual wound care practitioners specifically.

Objective： Noncystic fibrosis （non-CF） bronchiectasis remains as a common health problem in Asia. Pathogens＇ distribution in airways of patients with non-CF bronchiectasis is important for doctors to make right decision. Data Sources： We performed this systematic review on the English language literatures from 1966 to July 2014, using various search terms included ＂pathogens＂ or ＂bacteria＂ or ＂microbiology＂ and ＂bronchiectasis＂ or ＂non-cystic fibrosis bronchiectasis＂ or ＂non-CF bronchiectasis＂ or ＂NCFB.＂ Study Selection： We included studies of patients with the confirmed non-CF bronchiectasis for which culture methods were required to sputum or bronchoalveolar lavage fluid （BALF）. Weighted mean isolation rates for Haemophilus influenzae, Pseudomonas aeruginosa, Streptococcus pneumoniae, Stapylococcus aureus, Moxarella catarrhails were compared according to different methodology. Results： The total mean bacterial culture positive rates were 63%. For studies using sputum samples, the mean positive culture rates were 74%. For studies using BALF alone or BALF and sputum, it was 48%. The distributions of main bacterial strains were 29% for 1-1. influenzae, 28% for P. aeruginosa, 11% for S. pneumoniae, 12% for S. aureus, and 8% for M. catarrhails with methodology of sputum. Meanwhile, the bacterial distributions were 37% for H. influenzae, 8% for P aeruginosa, 14% for S. pneumoniae, 5% for S. attretts, and 10% for M. catarrhails with methodology of BALF alone or BALF and sputum. Analysis of the effect of different methodology on the isolation rates revealed some statistically significant differences. Conclusions： H. influenzae accounted for the highest percentage in different methodology. Our results suggested that the total positive culture rates and the proportion of P. aeruginosa from sputum and BALF specimens had significant differences, which can be used in further appropriate recommendations for the treatment of non-CF bronchiectasis.

Rhamnolipids are a class of biosurfactants that have a great potential to be used in industries. Five proteins/enzymes, namely RhlA, RhlB, RhlC, RhlG and RhlI, are critical for the production of rhamnolipids in Pseudomonas aeruginosa. Four of the 5 proteins except RhlC were successfully over-expressed in E. coli and three of them (RhlA, RhlB and RhlI) were purified and obtained in milligram quantities. The purified proteins were shown to be folded in solution. Homology models were built for RhlA, RhlB and RhlI. These results lay a basis for further structural and functional characterization of these proteins in vitro to favor the construction of super strains for rhamnolipids production.

Background： Healthcare-associated pneumonia （HCAP） is associated with drug-resistant pathogens and high mortality, and there is no clear evidence that this is due to inappropriate antibiotic therapy. This study was to elucidate the clinical features, pathogens, therapy, and outcomes of HCAP, and to clarify the risk factors for drug-resistant pathogens and prognosis. Methods： Retrospective observational study among hospitalized patients with HCAP over 10 years. The primary outcome was 30-day all-cause hospital mortality after admission. Demographics （age, gender, clinical features, and comorbidities）, dates of admission, discharge and/or death, hospitalization costs, microbiological results, chest imaging studies, and CURB-65 were analyzed. Antibiotics, admission to Intensive Care Unit （ICU）, mechanical ventilation, and pneumonia prognosis were recorded. Patients were dichotomized based on CURB-65 （lowvs. high-risk）. Results： Among 612 patients （mean age of 70.7 years）, 88.4% had at least one comorbidity. Commonly detected pathogens were Acinetobacter baumannii, Pseudomonas aeruginosa, and coagulase-negative staphylococci. Initial monotherapy with 13-1actam antibiotics was the most common initial therapy （50%）. Mean age, length of stay, hospitalization expenses, ICU admission, mechanical ventilation use, malignancies, and detection rate for P. aeruginosa, and Staphylococcus aureus were higher in the high-risk group compared with the low-risk group. CURB-65 ≥3, malignancies, and mechanical ventilation were associated with an increased mortality. Logistic regression analysis showed that cerebrovascular diseases and being bedridden were independent risk factors for HCAR Conclusion： Initial treatment of HCAP with broad-spectrum antibiotics could be an appropriate approach. CURB-65 〉3, malignancies, and mechanical ventilation may result in an increased mortality.

The growth of human population leads to intensification of agriculture and promotes, through eutrophication, development of cyanobacteria. One of the most widespread and bloom-forming species in freshwater is toxic Microcystis aeruginosa （M. aeruginosa）. Combustion of fossil fuels and metallurgical processes are the main sources of heavy metals contamination in surface water including cadmium （Cd） and lead （Pb）. The following study was conducted in order to determine the effect of 1- 20 mg. L-1 of Cd and Pb on photochemistry （using flow cytometry） and growth （based on chlorophyll concentra- tion） ofM. aeruginosa as well as to estimate levels of metal bioaccumulation. We have found that 1-10mg.L-1 of Cd and 1-5 rag. L1 of Pb induced continuous enhancement of chlorophyll fluorescence during 24 h of incubation. No significant degradation of chlorophyll was observed in these samples. At higher concentrations of 20 mg. L-1 of Cd and 10-20 mg.L-1 of Pb chlorophyll level significantly decreased and its fluorescence was quenched. M. aeruginosa demonstrated high capability of Cd and Pb bioaccumulation, proportionally to initial metal concentration. In samples with initial concentration of 20 mg. L-1 of Cd and Pb bioaccumulation of 87.3% and 90.1% was observed, respectively. Our study demonstrates that M. aeruginosa can potentially survive in highly metals polluted environments, be a primary source of toxic metals in the food chain and consequently contribute to enhanced toxicity of heavy metals to living organisms including human.

YfiBNR is a recently identified bis-（3＇-5＇）-cyclic dimeric GMP （c-di-GMP） signaling system in opportunistic pathogens. It is a key regulator of biofilm formation, which is correlated with prolonged persistence of infection and antibiotic drug resistance. In response to cell stress, YfiB in the outer membrane can sequester the pariplasmic protein YfiR, releasing its inhibition of YfiN on the inner membrane and thus provoking the diguanylate cyclase activity of YfiN to induce c-di-GMP production. However, the detailed regulatory mechanism remains elusive. Here, we report the crystal struc- tures of YfiB alone and of an active mutant YfiB^L43P complexed with YfiR with 2：2 stoichiometry. Structural analyses revealed that in contrast to the compact conformation of the dimeric YfiB alone, YfiB^L43P adopts a stretched conformation allowing activated YfiB to penebate the peptidoglycan （PG） layer and access YfiR. YfiBL43P shows a more compact PG-binding pocket and much higher PG binding affinity than wild-type YflB, suggesting a tight correlation between PG binding and YfiB activation. In addition, our crystallographic analyses revealed that YflR binds Vitamin B6 （VB6） or L-Trp at a YfiB-binding site and that both VB6 and L-Trp are able to reduce YfiBL43P-induced biofilm formation. Based on the structural and biochemical data, we propose an updated regulatory model of the YfiBNR system.

Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy （GC-MS） revealed the existence of phenol, 3, 5-bis （1, 1-dimethylethyl） in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas smtzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.