Effect of a compound starter cultures inoculation on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages

Effects of a starter culture composed of Lactobacillus sakei,Pediococcus pentosaceus,Staphylococcus xylosus and S.carnosus at the ratios(m/m)of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages were demonstrated.In starter culture-inoculated sausages,Lactobacillus spp.,Pediococcus spp.and Staphylococcus spp.were predominant bacterial genus and their relative abundances ranged from 70.14%to 25.98%,57.66%to 14.08%,and 15.71%to 13.40%during fermentation,respectively.Accordingly,Lactobacillus spp.and Weissella spp.were predominant bacterial genus and their relative abundances ranged from 63.14%to 24.70%and 49.40%to 11.96%during spontaneous fermentation,respectively.Furthermore,the abundances of undesirable microorganisms such as Yersinia spp.,Enterobacter spp.,Acietobacter spp.and Psychrobacter spp.were lower than that of the control.The levels of histamine,putrescine,tyramine and cadaverine in Chinese Sichuan sausages with starter cultures inoculation were significantly lower(P<0.05)than that of the control,and were decreased by 83.09%,69.38%,51.87%and 57.20%,respectively,at the end of the ripening.These results revealed that the starter cultures inoculation was a better alternative for microbial quality improvement and biogenic amine reduction of Chinese Sichuan sausages with good sensory attributes.

A Novel <i>in Vitro</i>Three-Dimensional Macroporous Scaffolds from Bacterial Cellulose for Culture of Breast Cancer Cells

In this work, patterned macropores with a diameter larger than 100 μm were introduced to pristine three-dimensional (3D) nanofibrous bacterial cellulose (BC) scaffolds by using the infrared laser micromachining technique in an attempt to create an in vitro model for the culture of breast cancer cells. The morphology, pore structure, and mechanical performance of the obtained patterned macroporous BC (PM-BC) scaffolds were characterized by scanning electron microscopy (SEM), mercury intrusion porosimeter, and mechanical testing. A human breast cancer cell (MDA-MB-231) line was cultured onto the PM-BC scaffolds to investigate the role of macropores in the control of cancer cell behavior. MTT assay, SEM, and hematoxylin and eosin (H&E) staining were employed to determine cell adhesion, growth, proliferation, and infiltration. The PM-BC scaffolds were found to be able to promote cellular adhesion and proliferation on the scaffolds, and further to allow for cell infiltration into the PM-BC scaffolds. The results demonstrated that BC scaffolds with laser-patterned macropores were promising for the in vitro 3D culture of breast cancer cells.

Differences in serum inflammatory mediators in early blood culture positive and negative patients with bacterial bloodstream infection

Objective: To study the differences in serum inflammatory mediators in early blood culture positive and negative patients with bacterial bloodstream infection. Methods: Patients who were hospitalized due to suspected bacterial bloodstream infection between December 2015 and September 2017 were divided into positive group and negative group according to the results of blood culture, and healthy volunteers who underwent medical examination during the same period were selected as control group. Peripheral blood specimens were collected from patients with suspected bacteremia on admission, the peripheral blood specimens were collected from the control group of volunteers during physical examination, and the levels of pro-inflammatory cytokines, anti-inflammatory cytokines, adhesion factors and chemokines were determined. Results: Serum PCT, CRP, IL-6, IL-17, IL-23, IL-4, IL-10, IL-13, sTM, ICAM-1, VCAM-1, EOTAXIN-3 and MCP-1 levels of positive group and negative group were significantly higher than those of control group, and serum PCT, CRP, IL-6, IL-17, IL-23, IL-4, IL-10, IL-13, sTM, ICAM-1, VCAM-1, EOTAXIN-3 and MCP-1 levels of positive group were significantly higher than those of negative group. Conclusions: Detection of serum inflammatory mediators can early predict the bacterial bloodstream infection.

Bacterial diversity in Arctic marine sediment determined by culture-dependent and-independent approaches

Bacterial diversity in surface sediment from the Arctic Ocean was investigated by culture-dependent and-independent approaches. Conventional culture-dependent techniques revealed 11 strains based on their distinct morphological characteristics on marine Zobell 2216E agar plates. Phylogenetic analysis showed that these isolates belonged to three major lineages of the Bacteria,γ-proteobacteria, Bacteroidetes and Actinobacteria, and that they included 10 genera. Most isolates were psychrotrophic, and NaCl was not necessary for their growth. Furthermore, they exhibited activity of at least one extracellular hydrolytic enzyme at 4＆#176;C and had various abilities to assimilate carbon sources. A total of 67 phylotypes were detected among 142 clones based on the 16S rRNA library of the total community DNA and grouped into nine major lineages of bacteria. Phylotypes afifliated withγ-,δ-andε-proteobacteria accounted for 36.7%, 21.8%and 16.9%of the total clones, respectively. The rest of the clones belonged to Bacteroidetes,α-proteobacteria, Actinobacteria, Fusobacteria, Nitrospirae and an unclassiifed group.

Progress in Diagnosis and Treatment of Small Intestinal Bacterial Overgrowth

Small intestinal bacterial overgrowth has been found to be associated with a variety of gastrointestinal disorders such as irritable bowel syndrome, inflammatory bowel disease, and, in recent years, diabetes mellitus and systemic sclerosis, among other extraintestinal diseases. Several novel diagnostic tools for small intestinal bacterial overgrowth have emerged in recent years, and several therapeutic approaches have been proposed. Therefore, it has become necessary to find an effective, safe, and simple diagnostic method and a safe treatment modality. This article provides a review of current diagnostic and therapeutic approaches to small intestinal bacterial overgrowth.

Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) Profile of Bacterial Community from Agricultural Soils in Bauchi, North-East Nigeria

The population dynamics of bacterial community was investigated in three Agricultural soils, designated as Loamy sand (A), Peaty coarse (B) and Loamy coarse sand (C) in North-East, Nigeria. The soil chemical properties were characterized to fully understand their nature. Metagenomic approach was used to extract soil DNA using the fast DNA Spin Kit extraction technique. The PCR-electrophoresed DNA bands were excised and subjected to a full scale Denaturing Gradient Gel Electrophoresis (DGGE) analysis. DGGE fingerprinting for the PCR-16S rDNA product revealed a diverse profile of complex population of bacterial community in the study area. The study shows that more bacterial community can be fully investigated using molecular techniques rather than traditional culture method. The implication of the results obtained is discussed.

Caries-related factors and bacterial composition of supragingival plaques in caries free and caries active Algerian adults

Objective: To compare oral hygiene practices, education and social background, food intake and oral malodor of Algerian adults suffering from dental caries with normal controls, and to determine and compare the bacterial composition of the supragingival plaques from the above-mentioned groups.Methods: Participants completed a questionnaire and were clinically examined for dental caries using decayed, missing and filled teeth index according to the criteria laid down by the World Health Organization. Supragingival plaque samples were collected from 50 caries-free adults(CF) and 50 caries-active adults(CA). Standard procedures of culture and identification of aerobic and anaerobic bacteria were used. Data were analyzed using Chi-square test.Results: A total of 117 bacterial strains were isolated from supragingival plaques in CF group subjects, 76(64.96%) of them belonged to 9 aerobic genera, and 41(35.04%) to 9anaerobic genera(P < 0.05). While in the second group, 199 strains were isolated, 119(59.80%) of the strains belonged to 10 aerobic genera and 80(40.20%) to 10 anaerobic bacteria(P < 0.05). Streptococcus mutans, Enterococcus faecium, Aerococcus viridans,Actinomyces meyeri, Lactobacillus acidophilus and Eubacterium limosum showed a significantly higher prevalence in the CA group(P < 0.05). The findings revealed that CA group had a high sugar intake(80%). A significantly higher frequency of tooth brushing(P < 0.000) and a significantly less self-reported oral malodor(P < 0.000) and tooth pain(P < 0.000) were found in CF group, while there was no association of socioeconomic levels and intake of meal snacks with dental caries.Conclusions: This study confirms the association of some aciduric bacteria with caries formation, and a direct association of sugar intake and cultural level with dental caries.Furthermore, oral hygiene practices minimize the prevalence of tooth decay.

Spontaneous bacterial peritonitis:risk factors and causative organisms

Objective:To determine the prevalent pathogens responsible for spontaneous bacterial peritonitis(SBP) and their sensitivity pattern,to test the efficiency of different culture techniques in microbial isolation,and to study the diagnostic predictors of such cases.Methods:One hundred eight SBP episodes from 92 adult patients were compared to 88 cirrhotic ascites patients cross - matched with age and sex without SBP.Ascitic fluid was subjected to cytological,biochemical examination and culture on both conventional and blood culture bottles at the bedside for bacterial identification and antimicrobial susceptibility testing.Results:The prevalence of SBP was 25.02%.Logistic regression analysis revealed that;previous SBP episode,low ascitic fluid protein levels, high serum creatinine and low serum albumin levels were the independent significant predictors of SBP.About forty - five per cent of SBP episodes were detected by conventional culture compared to 73.15%by modified technique with a significant difference.Gram - negative bacteria were the cause of SBP in 46(58.23%) culture positive episodes.Escherichia coli and Staphylococcus aureus were the most commonly detected organisms. Resistance to different antibiotics was high.Conclusion:Culture of ascitic fluid in blood culture bottles at bedside increases the sensitivity of SBP detection.There is a recent increase in Gram - positive pathogen with emergence of multidrug resistance.These recent changes may have an impact on guidelines for management and treatment of SBP in our locality.

Prevalence of bacterial vaginosis and its risk factors in HIV/AIDS patients with abnormal vaginal discharge

Objective:To determine the prevalence of bacterial vaginosis in the HIV/AIDS patients of primary health care clinics in Jos Plateau state,Nigeria.Methods:Female genital swabs were collected from primary health care centers,Jos and analyzed by microscopy,culture,etc.in Jos University Teaching Hospital from December 2006 to December 2007.Data on epidemiologic indices were collected,using structured interviewer-administered questionnaires.Results: The incidence of bacterial vaginosis in the study was 28%(n=196/700).Among the HIV/AIDS group,the bacterial vaginosis incidence was 36%(n=126/350),while in the control(non-HIV patients) group,the rate was 20%(70/350) with a statistically significant difference at 95 percent confidence level(P【0.05).HIV/AIDS and non-HIV(control) patients contributed 64%(n=126/196) and 36%(n=70/196),respectively.The risks to bacterial vaginosis included vaginal douching with disinfectant/detergent constituted(60%),poor use of condom 40%,a median age of 26 years,and a median number of 3 sex partners per week.Conclusions:There was a significant statistical difference in prevalence of bacterial vaginosis between the HIV/AIDS group and non-HIV(control) group of patients in the study.Risk behaviors that promote the incidence of bacterial vaginosis should be especially paid attention.

Growth Yields of Four <i>Coxiella burnetii</i>Isolates in Four Different Cell Culture Lines

Although Coxiella burnetii is considered to be an obligate intracellular bacterium and grows in embryonated eggs, laboratory animals and cell culture, recently it has been grown in cell-free media and on agar plates. This current study was conducted to compare four cell lines for their yield of C. burnetii. Four different isolates of C. burnetii (Henzerling, Arandale, Cumberland and Timony) were grown in DH82, L929, Vero and XTC-2 cell lines. The DH82 and XTC-2 cells lines produced the highest C. burnetii yield which was slightly less than the yields achieved in recently published studies using cell free media. The Arandale isolate of C. burnetii produced a significantly higher yield in DH82 cells compared to XTC-2 cells (P 0.03).

Clinical Presentation and Outcome of Bacterial Meningitis in University Hospital

Purpose: To determine the clinical characteristics and outcome of bacterial meningitis in adult patients using CT, MRI and CSF culture. Methods: Patients admitted to the university hospital with clinical diagnosis of meningitis were included in the present study. All patients were subjected to clinical examination as well as CT, MRI scanning and CSF-bacteriological culture. Results: The age distribution of the patients shows that there is high frequency of symptoms found in the age group between ages 40 - 45. CSF in the present study included WBS, RBC, glucose and protein, which is associated with the adverse outcome. Meningitis can be confirmed by many methods, in the present study three different methods were used, which included CT scan, MRI and CSF analysis and bacterial culture. In CT scan, among the predictors of meningitis, persons with TB (P = 0.037), patients with HIV (P = 0.036) and stroke (P = 0.036) showed significant association. Whereas MRI findings were significantly associated with TB meningitis (P = 0.015). Meningitis was prevalent in the age group of <45. Conclusion: This study highlights the importance of several modalities for diagnosing and predicting the outcome of meningitis in adults.

Value of Different Diagnostic Markers in Spontaneous Bacterial Peritonitis in HCV Egyptian Cirrhotic Patients

Background: Spontaneous bacterial peritonitis (SBP) is a life-threatening infection occurring in 8% - 30% of ascitic cirrhotic patients;different laboratory diagnostics play a pivotal role for rapid and effective management of SBP patients. Polymorphonuclear leucocytic (PMNLs) count in Ascitic fluid (AF) is the mainstay for the diagnosis, whereas the diagnostic role of alternative biomarkers is rather controversial. In many studies, serum lipopolysaccharide binding protein (LBP) was elevated and Complement 3 (C3) level was significantly consumed in AF of SBP patients. Objectives: To evaluate the diagnostic value of serum LBP and AF C3 in HCV-cirrhotics with SBP in relation to other well-established serum and AF markers. Patients and Methods: One hundred and twenty patients with HCV-cirrhosis and ascites were enrolled and consented: 50 patients with non-SBP ascites in group A and 70 ascitic patients diagnosed with SBP according to clinical suspicion and PMLs count in AF ≥ 250 cells/mm3 in group B in addition to 15 healthy individuals considered as a control group. Serum LBP, CBC, kidney and liver function tests, CRP, fasting and 2 h PP blood glucose and HCV antibodies were measured. AF samples were sent for C3 level, culture, PMNLs count, LDH, CRP, total proteins and albumin. Results: In patients with SBP, the level of serum LBP was not significantly high (p > 0.05) with best cut off value at 0.4500 and poor AUC (<0.6) with low sensitivity and specificity (53.3% & 57.7%, respectively). AF C3 was significantly reduced in AF (p < 0.001) with best cut off value at 144.2 and almost excellent AUC (0.889) with good sensitivity and specificity (82% & 84%, respectively). AF culture showed significant difference between both patients groups (p < 0.05) but with low sensitivity (33.3%). Serum and AF CRP and AF PMNLs count were of high significance in SBP diagnosis (p < 0.001). Conclusion: Serum LBP level showed low significance while AF C3 was significantly reduced in patients with SBP. AF culture showed significant difference between both groups but with low sensitivity while serum, AF levels of CRP and AF PMNLs count were highly significant, and the latter is still considered the gold standard for SBP diagnosis.

Microbial spectrum and drug resistance of pathogens cultured from gallbladder bile specimens of patients with cholelithiasis:A singlecenter retrospective study

BACKGROUND Bacterial infection is an important cause of cholelithiasis or gallstones and interferes with its treatment.There is no consensus on bile microbial culture profiles in previous studies,and identified microbial spectrum and drug resistance is helpful for targeted preventive and therapeutic drugs in the perioperative period.AIM To analyze the bile microbial spectrum of patients with cholelithiasis and the drug susceptibility patterns in order to establish an empirical antibiotic treatment for cholelithiasis-associated infection.METHODS A retrospective single-center study was conducted on patients diagnosed with cholelithiasis between May 2013 and December 2018.RESULTS This study included 185 patients,of whom 163(88.1%)were diagnosed with gallstones and 22(11.9%)were diagnosed with gallstones and common bile duct stones(CBDSs).Bile culture in 38 cases(20.5%)was positive.The presence of CBDSs(OR=5.4,95%CI:1.3-21.9,P=0.03)and longer operation time(>80 min)(OR=4.3,95%CI:1.4-13.1,P=0.01)were identified as independent risk factors for positive bile culture.Gram-negative bacteria were detected in 28 positive bile specimens,and Escherichia coli(E.coli)(19/28)and Klebsiella pneumoniae(5/28)were the most frequently identified species.Gram-positive bacteria were present in 10 specimens.The resistance rate to cephalosporin in E.coli was above 42%and varied across generations.All the isolated E.coli strains were sensitive to carbapenems,with the exception of one imipenem-resistant strain.K.pneumoniae showed a similar resistance spectrum to E.coli.Enterococcus spp.was largely sensitive to glycopeptides and penicillin,except for a few strains of E.faecium.CONCLUSION The presence of common bile duct stones and longer operation time were identified as independent risk factors for positive bile culture in patients with cholelithiasis.The most commonly detected bacterium was E.coli.The combination ofβ-lactam antibiotics andβ-lactamase inhibitors prescribed perioperatively appears to be effective against bile pathogens and is recommended.Additionally,regular monitoring of emerging resistance patterns is required in the future.

Antibacterial effect of povidone iodine disinfectant and antibiotic eye drops before cataract surgery

Objective:Investigate the distribution of bacteria in the conjunctival sac of two groups of cataract patients with different preoperative aseptic treatments,and compare the clinical effects of 0.5%povidone-iodine(PI)and antibiotic eye drops on killing conjunctival sac bacteria.Methods:400 cases of patients(400 eyes)who underwent cataract surgery in the Department of Ophthalmology of Baogang Hospital in Inner Mongolia from October 2019 to October 2020 were selected in a randomized controlled study.They were randomly divided into the experimental group(group A)and the control group(group B),with 200 cases in each group.Group A:the patients were given Gatifloxacin Eye Gel(3 times/day,1 drop/time)combined with Diclofenac Sodium Eye Drops(4 times/day,1 drop/time)before the operation;0.5%PI was administered to irrigate the conjunctival sac,with 0.9%Sodium Chloride Injection washing after 3 min;0.5%PI was administered to irrigate the conjunctival sac after operation.The corneal epithelium was observed after each irrigation.Group B:the patients were given Gatifloxacin Eye Gel(3 times/day,1 drop/time)combined with Diclofenac Sodium Eye Drops(4 times/day,1 drop/time)2 days and 1 day before the operation;0.9%Sodium Chloride Injection was administered to irrigate the conjunctival sac before and after surgical disinfection.Conjunctival sac specimens were collected for bacterial culture 2 hours before the operation,after irrigation,and after the procedure.The positive rate and the distribution of bacteria were compared between the two groups.Results:The difference in the positive rate of bacteria in the conjunctival sac between the two groups at different time points had a statistical significance(χ^(2)=11.498,p<.022).Conjunctival sac specimens were collected on admission and 2 hours before the operation.There was no significant difference in the pathogens with positive results between the two groups(p=.955;p=.073);there was a substantial difference in the distribution of positive pathogens between the two groups before and after surgical disinfection(p<.001);there was a significant difference in the distribution of pathogens between the two groups after the operation(p=.005).For Staphylococcus epidermidis,Corynebacterium,Enterococcus faecalis,Streptococcus,and other Gram-positive bacteria,there was a significant difference in the disinfection methods between the two groups at different time points(p<.001);for Staphylococcus aureus,Gram-positive cocci,and Gram-negative bacteria,there was no significant difference in the disinfection methods between the two groups at different time points(p=.113;p=.224;p=.146).There was no significant difference between the two groups with 0-10 and 101-1000 bacterial colonies at different time points(p=.370 and.071,respectively).When there were 11-100 bacterial colonies,there was a significant difference between the two groups at different time points(p<.001).There was no significant difference in corneal epithelial injury between the two groups at other time points(χ^(2)=4.133,p=.127).Conclusions:The combination of 0.5%PI disinfectant and antibiotic eye drops can effectively reduce the bacterial load of the conjunctival sac before operation.At the same time,it is safe and effective to irrigate the conjunctival sac with 0.5%PI disinfectant before the procedure.

mNGS对肝硬化自发性腹膜炎患者的诊断与预后的临床应用价值

目的探究宏基因组二代测序(mNGS)对于自发性细菌性腹膜炎患者的早期诊断与预后的价值。方法纳入2021年3月至2023年3月期间肝硬化腹水患者60例。进行腹水培养和腹水mNGS检测。比较mNGS阳性与阴性组患者一般临床资料、APRI指数、FIB-4指数、MELD评分、MELD-Na评分和Child-Pugh评分。采用腹水多核白细胞计数(PMN)联合腹水mNGS诊断自发性细菌性腹膜炎。结果2组患者的基本资料差异无统计学意义(P>0.05)。PMN联合腹水mNGS检测诊断自发性细菌性腹膜炎的敏感度为86.67%,特异度为78.86%。随访结果显示,mNGS阳性组具有更高的不良事件发生率、病死率和肝硬化相关指标评分。腹水mNGS阳性组和腹水mNGS阴性组的MELD评分分别为18.25和13.11、MELD-Na评分分别为23.82±11.77和14.58+11.27、Child-Pugh评分分别为11.25和9.75。结论PMN联合mNGS检测诊断自发性细菌性腹膜炎优于联合腹水培养,mNGS阳性与肝硬化自发性细菌性腹膜炎患者发生不良预后有较高的相关性。

多重PCR毛细管电泳细菌快速鉴定方法的建立和临床应用研究

目的针对引起人类感染的常见病原菌建立一种基于多重PCR毛细管电泳技术的快速细菌鉴定方法,评估其临床应用价值。方法建立23种常见病原菌的多重PCR毛细管电泳检测体系。收集150例临床微生物检测标本,分别用多重PCR毛细管电泳法(以下简称多重PCR法)、培养法进行检测。对两种方法的检测结果进行比较,评价多重PCR法的检测效能。结果150例标本中多重PCR法检出15种病原菌、培养法检出14种病原菌。多重PCR法检测阳性率为73.3%,培养法为70.0%,差异无统计学意义(P>0.05)。多重PCR法对肺炎链球菌的检出率为16.0%,培养法为6.0%,差异有统计学意义(P<0.05)。多重PCR法对混合菌标本的检出率为15.3%,培养法未检出混合菌标本。多重PCR法与培养法检测结果的符合率为79.3%。多重PCR法检测时间为3~6 h,培养法为2~4 d。结论与培养法比较,多重PCR法具有较高的时效性,对肺炎链球菌及混合菌标本具有较高的检出率,可满足临床标本病原微生物快速初筛的需求。

纳米孔测序检测嗜麦芽窄食单胞菌重症肺炎1例报告

嗜麦芽窄食单胞菌肺炎是一种因嗜麦芽窄食单胞菌感染所致的肺炎。采用传统病原菌培养法检测,阳性率低,假阴性率高、周期长,病原学证据短期内无法正确获得,影响预后。本文探讨一种较为快速准确的检测方法。纳米孔测序(NTS)是一种第三代测序技术,相比传统方法优点是它的成本和时间效益,吞吐量高。本文检测了1例由嗜麦芽窄食单胞菌引起的重症肺炎。结果表明,该病是由嗜麦芽窄食单胞菌引起的感染。本文提供了NTS可以快速识别病原体的证据,这对临床诊断和治疗具有重要意义。

经鼻颅底手术患者术中鼻腔细菌培养及临床分析

目的 分析临床经鼻颅底手术术区细菌存留情况及其与术后颅内感染的相关性。方法 将经鼻颅底肿瘤(蝶鞍区及鞍上)切除术患者的手术过程分为鼻腔通道准备(第1阶段)、肿瘤切除(第2阶段)和颅底重建(第3阶段)3个阶段,在每个阶段的起始时点,于蝶窦前壁或鞍底斜坡隐窝处黏膜各取样1次进行细菌培养,分析手术不同阶段细菌培养阳性率及其与术后颅内感染的相关性。结果 共纳入患者105例,共取样315例次,3个阶段取样的中位时间点分别为手术开始后20.3、45.1、131.3 min。细菌培养的阳性结果第1阶段、第2阶段、第3阶段分别为9例(2.9%)、8例(2.5%)、23例(7.3%),其中第1阶段或第2阶段与第3阶段阳性例数差异均有统计学意义(P=0.013;P=0.007),而第1阶段与第2阶段差异无统计学意义(P=0.955)。共检出表皮葡萄球菌24例,金黄色葡萄球菌7例,溶血性链球菌3例,肺炎克雷伯杆菌2例,大肠杆菌4例。3阶段至少1次阳性结果的有36例(11.4%),术后17例(16.2%)脑脊液漏,12例(11.4%)颅内感染。细菌培养阳性患者发生颅内感染的危险性是阴性患者的3.1倍(OR=3.1,95%CI:0.9~10.6),但差异尚无统计学意义;脑脊液漏患者发生颅内感染的危险性是非脑脊液漏的61.4倍(OR=61.4,95%CI:11.2~337.1),差异有统计学意义(P<0.001)。术区鼻腔和术后脑脊液培养结果的菌种一致率为57.1%。结论 经鼻颅底手术术区细菌培养阳性率随手术时间延长而明显增高,是术后颅内感染的潜在风险指标。

福建东吾洋海域海水和沉积物菌群结构及其与环境因子相关性

福建东吾洋海域是我国刺参(Apostichopus japonicus)吊笼养殖的核心产区,但目前该地区的水域环境现状和环境菌群结构相关研究匮乏。本研究以东吾洋海域东安、马坑、雷江和沙湾4个主要养殖区域为对象,完成了海参养殖高峰期1月的水质环境因子调查和评价分析,采用高通量测序方法完成了水体和沉积物菌群多样性和差异特征菌群分析,解析了环境因子与菌群结构相关性。结果表明,马坑海域的富营养化指数为21.60,属于严重富营养化;东安和雷江海域属于重度富营养,只有沙湾海域处于中度富营养的水平。东安和沙湾海域水质属于轻度有机污染,而马坑和雷江海域属于中度有机污染。高通量测序共获得1 520个操作分类单元(operational taxonomic units, OTUs),归属于28门、57纲、163目、322科、581属。菌群结构多样性分析表明,各区域沉积物的菌群多样性水平均显著高于相应海域水体菌群多样性,且具有较强的空间异质性。沙湾海域环境菌群多样性与丰度最高。PCo A分析表明,沉积物和水体中细菌群落结构差异极显著,水体交换和海域位置对其水体和沉积物菌群结构的影响较大。具有潜在致病性的弧菌科(Vibrionaceae)在所有水体和沉积物样本中均为优势种类之一。对水体样品和沉积物样品的LEFSe(line discriminant analysis effect size)分析筛选到处于不同分类水平的74个特异菌群。基因功能的预测和COG分类统计表明,水体与沉积物样品在12个代谢途径上存在显著差异(P<0.05)。对4个海区的水体菌群LEFSe分析筛选到处于不同分类水平的30个特异菌群。水体的菌群与环境因子的RDA分析揭示,温度、溶氧、叶绿素a浓度是影响不同海域水体菌群结构的主要环境因子,相关研究将为福建刺参养殖管理提供基础数据和科学参考。

水华对中华绒螯蟹(Eriocheir sinensis)池塘养殖系统细菌群落及潜在致病菌的影响

近年来,水华频发制约着中华绒螯蟹养殖业的发展,环境微生物群落响应水华发生与消退机制是预防与治理水华的重要组成部分。为了解析中华绒螯蟹养殖系统细菌群落对水华的响应特征,采用16S rRNA基因扩增测序技术对拟浮丝藻水华下中华绒螯蟹养殖池塘细菌群落的组成、结构和潜在病原菌的变化进行了研究。结果显示,水体中的优势细菌类群为伯克霍尔德菌科(Burkholderiaceae)和微杆菌科(Microbacteriaaceae),底泥中的优势类群为Steroidobacteraceae菌科和Burkholderiaceae等;科水平下的蓝细菌门类群和其他大部分细菌群落呈显著正相关。养殖水体中潜在病原菌的丰度与水华的生消呈现出相反的趋势,OTU365和OTU1614(均属于Candidatus Similichlamydia epinepheli)是其主要的潜在病原菌,而在底泥中潜在致病菌表现出富集的特征,以OTU1280(大肠杆菌,Escherichia coli)为主。CCA结果显示,蓝藻暴发过程中,Tem、NO3--N、NO2--N及NH4+-N驱使水体蓝藻门细菌类群的变异,NO2--N是驱动养殖水体潜在致病菌群落变异的主导因子。研究结果为防治中华绒螯蟹养殖水华发生提供了宝贵的数据支撑。