人工湿地中指示与病原微生物动态分布及相关性分析

选择总大肠菌群(total coliforms)、粪大肠菌群(fecal coliforms)、粪链球菌(fecal streptococci)、大肠杆菌(Escherichia coli)、产气荚膜梭菌(Clostridium perfringens)和沙门氏菌(Salmonella spp.)6种指示和病原微生物,采用多管发酵法和倾注平板法研究其在自由表面流人工湿地中的去除效果、相关性及动态分布特征.结果表明:人工湿地进水中沙门氏菌数量最多,其次为总大肠菌群、粪大肠菌群、产气荚膜梭菌和大肠杆菌,粪链球菌数量最低;人工湿地对不同指示和病原微生物去除效果存在差异,对总大肠菌群、粪大肠菌群和大肠杆菌去除效果最好,年平均去除率分别为94.1％、93.4％和84.0％;对沙门氏菌和产气荚膜梭菌去除效果较差,年平均去除率分别为55.8％和63.6％,并且存在较大波动;出水中粪链球菌数量高于进水;人工湿地对指示和病原微生物的去除效果在不同季节间无显著差异,但迸水中总大肠菌群数量、进出水中沙门氏菌数量及进水中产气英膜梭菌数量在不同季节间存在差异.相关性分析表明,总大肠菌群、粪大肠菌群以及大肠杆菌之间存在较强相关性,沙门氏菌和粪大肠菌群以及产气荚膜梭菌和总大肠菌群、粪大肠菌群间存在弱相关性.     

水中粪大肠菌群测定方法-纸片快速法与多管发酵法的比较

2015年10月国家环境保护部发布了行业标准《水质总大肠菌群和粪大肠菌群的测定纸片快速法》(HJ755-2015)(以下简称纸片快速法)。之前环境监测部门一直在使用国家环境保护部于2007年3月发布的行业标准《水质粪大肠菌群的测定多管发酵法和滤膜法(试行)》(HJ/T347-2007)(以下简称多管发酵法)。纸片快速法操作简单快速,在标准中对采样瓶的处理、样品的保存、水样的稀释接种等做出了详细的规定,而多管发酵法中没有相应规定。本文对两个标准的异同点进行比较,提出了将这两种方法的优点应用于实际环境监测工作中。     

在饮用水中协同检测“粪型大肠菌群”的试验方法

阐述了在饮用水中检测"粪型大肠菌群"的意义,强调了大肠菌群与粪型大肠菌群的关系,总结出"粪型大肠菌群"的检测条件。     

应用定量微生物风险评估海水浴场人体健康风险

【背景】定量微生物风险评估作为定量评估游泳人群暴露于病原微生物后健康风险的方法,在国外已得到广泛应用,但目前国内的应用处于起步阶段且缺乏所需的游泳人群暴露数据。【目的】收集游泳人群暴露数据,并在海水浴场中进行应用,评估粪大肠菌群作为风险评估指标的可行性。【方法】通过对6个典型海水浴场的水质状况、粪大肠菌群浓度与环境因子的相关性进行分析,并发放调查问卷收集国内游泳人群的暴露数据,进而应用定量微生物风险评估方法,得出各个海水浴场的胃肠道疾病患病风险。【结果】6个海水浴场中粪大肠菌群浓度均与水温、气温及总云量具有显著相关性(P<0.01)。位于南方的海水浴场粪便污染情况较北方严重,粪大肠菌群浓度第95百分位数远高于国内“差”类水质标准的阈值。儿童、成年男性、成年女性单次沐浴事件吞下海水的体积分别为35.1 mL (95%置信区间为32.4-37.8,α=0.578,β=0.016),45.0 mL (95%置信区间为31.1-59.3,α=0.532,β=0.012),35.7 mL (95%置信区间为29.7-41.8,α=0.753,β=0.032)。6个海水浴场患胃肠道疾病的风险...     

荧光原位杂交(FISH)技术检测水体中大肠菌群研究

大肠菌群广泛用作饮用水的细菌学检测指标。传统的检测方法有多管发酵法和滤膜法。这些方法存在一些缺点 ,如检测时间长、专一性差、干扰因素多。因此 ,迫切需要一些快速、灵敏的检测方法。FISH(fluorescentinsituhybridization)技术利用寡核苷酸探针检测特定细胞内的互补核苷酸序列。针对于Enterobacteriaceae的 1 6SrRNA分子区域专门设计的探针可以用于饮用水样品的微生物检测。FISH技术可以用于饮用水中大肠菌群的检测 ,并且在较短的时间内 ( 6～ 8h)给出定量分析结果 ,但该技术用于日常检测尚需更深入的研究。     

野生大鸨的粪便成分分析

目的 通过检测野生大鸨的粪便成份和鸡粪、麦苗中成份对比,分析大鸨的消化能力.方法灰分、磷和粗蛋白分别用国标GB/T6438-1992、GB/T6437-1992和GB/T6432-1994法,钙用原子吸收,氨基酸用PI-CO-TAG氨基酸分析法.结果 大鸨粪便中粗蛋白为85.42%、粗厌分为25.56%、钙为3.30 mg/kg、磷为0.47%.大鸨粪中的脯氨酸和甘氨酸的含量比鸡粪中高;麦苗中多数氨基酸含量比大鸨粪中高,酪氨酸最高(达4.3倍).结论 3月份大鸨食物(麦苗)中钙磷不足,需要补充;氨基酸供应不平衡.     

模拟稳定塘系统对污染指示菌的去除作用

本文研究了模拟稳定塘系统去除污染指示菌如总大肠菌群(TC),粪大肠菌群(FC),粪链球菌(FS)以及异养细菌(HPC)的作用。结果表明,16℃时污水在日进污水10t的模拟稳定塘系统停留9天后,TC与FC的密度下降4个数量级。在日进污水90t,污水理论水力停留时间10天的模拟稳定塘系统进行的全年跟踪监测结果表明,TC与FC密度随各塘依次递减。Ⅳ号塘出水的TC密度下降2.5个数量级,基本上达到了我国GB3838-88中规定的地面水Ⅲ级标准;FC密度下降3个数量级,达到WHO标准的轻污染水平,肯定了稳定塘系统去除污染指示菌的有效性。     

Kato—Katz法与改良洪氏虫卵计数法检出钩虫卵效果比较

1987年于云南省巍山县安章伍村对KatoKatz法(简称卡氏法)、改良洪氏虫卵计数法(简称洪氏法)检出钩虫卵效果作了比较,现将结果报告如下。方法一、对5周岁以上居民以小酒杯饱和盐水漂浮法查出钩虫卵阳性者分别同时以洪氏法、卡氏法计数。并与玻管滤纸培养法(简称培养法)进行比较。二、以钩虫卵在50个/克粪以下粪便,经108目尼龙绢滤渣,同时作洪氏法和卡氏法,比较检出效果。三、在气温20.5～16℃、湿度55～63%条件下,同时以同一粪样制作3张玻片,以卡氏法定时观察计数钩虫卵。结果共检查229人,钩虫卵阳性者24人(10.5%)。以洪氏法计数18人,EPG算…     

长江下游地区中国荷斯坦奶牛生乳中菌落总数的影响因素分析

【背景】随着人们生活水平和健康意识的提高,作为部分乳制品的原料,生乳的质量安全问题显得尤为重要。【目的】检测长江下游地区某集约化牧场中国荷斯坦奶牛生乳中菌落总数、总大肠菌群数的真实水平,同时对影响其变化的生理因素和环境因素进行探讨。【方法】以中国荷斯坦奶牛生乳为研究对象,用乳房炎快速诊断剂检测乳房炎感染情况,菌落总数、总大肠菌群数和环境细菌数的检测方法参照国家标准。对采集的生乳样本进行细菌常规分离鉴定,同时收集乳成分变化数据。【结果】多因素方差分析结果表明,不同泌乳阶段和不同产奶量对荷斯坦奶牛生乳中菌落总数的影响显著(P0.05)和极显著(P0.01);体况、泌乳阶段、胎次、产奶量及乳区对大肠菌群数均无显著影响(P0.05)。夏季生乳的菌落总数、大肠菌群数均极显著地高于其他季节(P0.01);场区内各牛舍的不同卫生环境及细菌数对菌落总数、大肠菌群数的影响均在显著以上(P0.05)。不同乳房炎的感染程度对菌落总数影响极显著(P0.01)。细菌鉴定结果是葡萄球菌属和杆菌属感染居多,链球菌属感染几乎没有。菌落总数的变化对乳蛋白率影响不显著(P0.05),对乳脂率的影响极显著(P0.01)。【结论】随机采样泌乳牛群的不同生理和病理状况、外界不同饲养条件及卫生环境对生乳中菌落总数和大肠菌群数有不同程度的影响,生乳的乳脂率与细菌总数变化负相关。     

PCR技术检测水体中大肠菌群的研究

大肠菌群被广泛用作饮用水的卫生学检测指标。传统的检测方法耗时长、专一性差、干扰因素多。因此 ,迫切需要开发快速、灵敏的新方法。近年来 ,应用PCR技术检测水体中大肠菌群的研究报道不断增多。利用PCR技术扩增编码lacZ基因 ( β 半乳糖苷酶基因 )和uidA基因 ( β D 半乳糖苷酶基因 )的DNA片段 ,可以分别检测总大肠菌群和E .coli。但目前利用PCR进行定量分析还缺乏精度 ,需要进行更深入的研究。     

应用不同方法检测食品中大肠菌群结果的比较

评价检测食品中大肠菌群不同方法。比较国家标准、行业标准和显色培养基检测方法检测大肠菌群结果的差别。国家标准和行业标准检测结果基本一致,但有差异,应用显色培养基检测大肠菌群优于目前使用的国家标准和出口食品检验行业标准方法。检测食品中大肠菌群,显色培养基检测方法快速、灵敏、特异。     

Comparison of media for enumeration of coliform bacteria and Escherichia coli in non-disinfected water

In this work alternative media for detection and enumeration of E. coli and coliform bacteria were compared to the reference method ISO 9308-1 (LTTC) using non-disinfected water samples with background flora. The alternative media included LES Endo agar medium (LES Endo), Colilert-18 with 51-well Quanti-tray (Colilert), Chromocult Coliform agar (CC), Harlequin E. coli/Coliform medium (HECM) and Chromogenic Escherichia coli/Coliform medium (CECM). A total of 110 samples of groundwater, bathing water and spiked water was used. Our results revealed that confirmation of coliform bacteria counts is necessary, not only on lactose-based LTTC and LES Endo media, but also on the chromogenic agar media tested, due to the growth of oxidase positive colonies. LTTC and CC media also allowed the growth of some morphologically typical coliform colonies containing gram-positive bacteria. The recovery of coliform bacteria was lower on LES Endo than on LTTC. In most cases Colilert, CC, HECM and CECM gave higher coliform counts than LTTC. The use of the LTTC medium led to higher E. coli counts than obtained with any of the alternative mediums. There are three explanations for this: (1) high sensitivity of LTTC, (2) false positives on LTTC or (3) false negatives especially with Colilert, but also with chromogenic agar media. Although LTTC was found to be a very sensitive medium, the high degree of background growth of non-disinfected waters disturbed substantially the use of it. In conclusion, our results suggest that Colilert, CC and CECM are potential alternative media for detection of coliform bacteria and E. coli from non-disinfected water.     

The effect of the method of inoculation on the growth and variability of Bacillus thuringiensis H14 266/2-1

The method of inoculation was studied for its effect on the growth and variability of Bacillus thuringiensis H14 266/2-1 when cultivating them in the liquid nutrient medium inoculate with inoculum prepared by different procedures. Optimal conditions of the inoculum preparation are determined. Productivity of the strain when inoculating the medium with the aerial-dry inoculum was studied as compared to the inoculation by the inoculum taken from the mown agar. It is established that selection of the virulent R-form from colonies should serve as a basis for the preparation of the stable morphologically uniform inoculum. The aerial-dried culture of bacilli is shown to be more effective since it is characterized by higher and stable indices of productivity and is more prepared to a long-duration storage than the inoculated agar media. A more rapid transition (by 2-4h) of the culture to the use of the carbon source is marked. The culture of bacilli is different in a higher developmental level: sporulation and crystallization initiate during the first hours of inoculation and by the 24th hour sporulation reaches 100% with the prevailing content of R-form.     

Effect of cephalexin on the colonization resistance of the large intestine in experimental animals

It was shown morphologically and microbiologically that cephalexin administered intragastrically in a dose of 2 g/kg induced deep microecological changes in the cecum of Wistar albino rats. Scanning electron microscopy revealed that a single use of cephalexin in the above dose resulted in almost complete elimination of the biofilm from the surface of the cecum mucosa and it inflammation. This was accompanied by an increase in the number of potentially pathogenic bacteria and broadening of the spectrum of the phage variants of coliform bacilli present in the animal feces, as well as by change the periods of coliform bacilli persisting in the large intestine.     

Isolation of bacteria and fungi from human sputum and faeces using carbon monoxide as source of energy and carbon

Seventy-five sputa and 10 faeces of human origin were examined for organisms capable of growing in carbon monoxide (CO). Specimens were plated onto a buffered agar medium containing trace vitamins, and incubated (2–4 weeks) in 60% v/v CO as the sole source of carbon and energy. All specimens yielded growth except for three sputa; many individual colonies were shown to comprise at least two different organisms. While no recognized carboxydotrophs were found, presumptive identification revealed that streptococci, staphyloccoci, coliform bacilli, yeasts and moulds were all represented. Using a specific enzyme test, evidence for CO dehydrogenase activity was found in a significant proportion of mixed and purified cultures. These studies indicate that CO-tolerant organisms which may be using CO as a source of carbon and energy are associated with man.     

A Note on the Use of Membrane Faecal Coliform Medium for Enhancing Resolution and Accuracy when Enumerating a Small Plaquing Coliphage

A modified membrane faecal coliform (mFC) medium was used to improve resolution and accuracy when enumerating plaques of bacteriophage MS2. The method enables an economical and rapid drop-count technique to be used.     

Inhibition of growth of tubercle bacilli by ali-esterase inhibitors in various culture media

Summary The effect of the potent ali-esterase inhibitor E 600 (paraoxon) on the growth of tubercle bacilli is potentiated by the addition of Tween 80 to the medium. This may be due to a change in the permeability of the bacteria for the inhibitor. Growth of tubercle bacilli from sputa is also inhibited by E 600 in the haemolysed human blood medium of Price. Cultures of tubercle bacilli in media with E 600 begin to grow after some time, when the inhibitor has broken down. The results obtained by the method of Price indicate that growth of the cultures does not originate from a few resistant cells but from the whole population which may have regained the ali-esterase activity essential to their growth.     

Inhibition of Shigella flexneri by the Normal Intestinal Flora II. Mechanisms of Inhibition by Coliform Organisms

Of 15 strains of coliform bacteria, all isolated from human feces, 14 inhibited the growth of Shigella flexneri in mixed culture. In every case, when inhibition occurred, exponential growth of Shigella was interrupted in the mixed culture and the organisms entered into either a stationary or a death phase. None of the test coliform strains produced colicines active against Shigella. An analysis of mixed-culture environments at the time Shigella inhibition occurred revealed that the inhibition was not due to nutrient depletion nor to the development of adverse pH or oxidation-reduction potentials in themselves. In mixed cultures, the coliform strains produced formic and acetic acids in concentrations that inhibited Shigella growth. With one exception, the coliform strains also greatly reduced the culture medium. In average concentrations produced, the formic and acetic acids exerted a bactericidal effect on Shigella under the reduced conditions found in mixed cultures. The acids were only moderately toxic for the coliform strains under the same conditions. Results indicate that volatile acid production and concomitant reduction of the medium are the mechanisms by which coliform bacteria inhibit Shigella growth in mixed cultures.     

Hospital outbreak of trimethoprim resistance in pathogenic coliform bacteria.

In an investigation of outbreak of infection caused by coliform bacilli with plasmid-mediated trimethoprim (TMP) resistance many patients were found to be asymptomatic carriers of TMP-resistant coliform bacilli. Analysis of factors predisposing to rectal carriage of these organisms showed that the most important was previous treatment with co-trimoxazole, a sulphonamide, or ampicillin. The outbreak was controlled by a policy restricting the antibiotics given. Geriatric units are an important source of hospital infection. When an outbreak occurs the logical sequence of steps to be taken is to monitor cases, identify the outbreaks, analyse the causative factors, plan corrective action jointly with laboratory staff, and monitor the outcome.     

Rapid detection of total and fecal coliforms in water by enzymatic hydrolysis of 4-methylumbelliferone-beta-D-galactoside

Three fluorogenic methylumbelliferone (MU) substrates were evaluated for rapid detection of total and fecal coliform bacteria (TC and FC) in drinking water. 4-MU-beta-D-galactoside, MU-heptanoate, and MU-glucuronide were used to determine enzyme activity as a surrogate measure of coliform concentration. Coliforms occurring in river water and in potable water artificially contaminated with raw sewage were tested. The initial rate of hydrolysis (delta F) of MU-beta-D-galactoside showed promise as an indicator of TC and FC within 15 min. delta F of MU-glucuronide was insufficient in the 15-min assay, and combinations of the MU substrates did not enhance delta F. A direct membrane filter method incorporating MU-beta-D-galactoside into an agar medium allowed the detection of as few as 1 FC per 100 ml within 6 h.