外排泵adeB基因与鲍曼不动杆菌多重耐药的关系

目的探讨临床分离鲍曼不动杆菌主动外排基因ade B的表达与其多重耐药的关系。方法对临床分离的64株鲍曼不动杆菌采用纸片扩散法检测对抗菌药物的敏感性;罗丹明6G检测外排活性,RT-PCR检测外排泵基因ade B的分布和表达水平。结果 64株鲍曼不动杆菌耐0~2种抗菌药物4株,耐3~5种抗菌药物33株,耐6~8种抗菌药物27株;罗丹明6G外排实验显示,外排增强的多重耐药菌株其外排基因ade B的表达明显增高。结论药物主动外排增强与鲍曼不动杆菌多重耐药相关;外排基因的过度表达可能是导致鲍曼不动杆菌多重耐药的主要原因。     

鲍曼不动杆菌临床分布特征及耐药性分析

目的:探讨200株鲍曼不动杆菌临床分布特征及耐药性情况。方法:分析临床科室向微生物实验室送的临床标本临床科室向微生物实验室送的临床标本。结果鲍曼不动杆菌的检出标本主要见于痰及支气管吸出物、切口的分泌物、尿液、血液、腹水及胸水等,根据其检出鲍曼不动杆菌标本的特点,可以分析出鲍曼不动杆菌大多分布在呼吸科、重症监护病房、急诊监护病房等,200株鲍曼不动杆菌中,48株鲍曼不动杆菌呈多重耐药菌株,对头孢哌酮/舒巴坦耐药率最低(10.0%),氨苄青霉素(98.0%)耐药率最高。结论:应加强对鲍曼不动杆菌耐药性的监控并防治耐药菌株的传播流行,为临床使用抗生素治疗提供依据。     

638株鲍曼不动杆菌的临床分布及耐药性分析

目的:了解本院鲍曼不动杆菌的临床分布情况及耐药特点,为临床合理使用抗菌药物和有效控制感染提供参考依据。方法:收集2015年1月-2016年9月本院各科室的各类临床送检标本,分离鲍曼不动杆菌,进行细菌鉴定和药敏试验,分析其感染分布和耐药情况。结果:共检出鲍曼不动杆菌638株,其中以痰液检出最多,共560株(87.8%),其次为伤口分泌液35株(5.5%);鲍曼不动杆菌在ICU、急诊内科、呼吸内科检出率较高,分别占比30.9%、30.4%和11.1%。鲍曼不动杆菌对阿米卡星的耐药率最低(45.0%),其次为复方新诺明(69.2%),其余16种抗菌药物的耐药率均超过70%,多重耐药较为严重。结论:鲍曼不动杆菌主要引起呼吸道感染,对多种抗菌药物的耐药严重,临床医生要重视该菌,加强对该菌的监测,合理使用抗菌药物,以减少耐药菌株的产生。     

91株鲍曼不动杆菌临床分布特点及药敏结果分析

目的:了解鲍曼不动杆菌的感染情况及其耐药性,为临床合理应用抗生素提供科学依据。方法:收集本院临床分离的鲍曼不动杆菌91株,分析其科室分布、标本来源及耐药情况。结果:鲍曼不动杆菌主要分布在神经外科病房、干诊三病房和呼吸病房,均为26.4%,以痰液分离最多,为87.9%;哌来西林/他唑巴坦耐药率为32.8%、亚胺培南和美罗培南耐药率为34.0%。结论:鲍曼不动杆菌的耐药机制复杂,应加强医院耐药菌株的监测,指导临床合理使用抗生素,采取有效的防范措施最大限度减少鲍曼不动杆菌感染。     

衡阳地区鲍曼不动杆菌基因分型及医院感染分布情况

目的研究鲍曼不动杆菌医院感染分子流行病学的情况,为控制医院感染提供直接、可靠的参考依据。方法对衡阳地区2011年1月～12月临床送检18 000份标本中分离出的480例鲍曼不动杆菌的药敏试验结果等进行回顾性分析,了解鲍曼不动杆菌医院感染现状;建立随机扩增多态性DNA(RAPD)基因分型方法对其中140株多重耐药鲍曼不动杆菌进行基因分型。结果 480例鲍曼不动杆菌标本主要来自ICU、呼吸内科、烧伤科等;标本分布以痰标本最高占65.0%,其次为伤口分泌物标本占20.0%,中段尿10.0%,其它类型标本占5.0%;480株鲍曼不动杆菌的多重耐药情况非常严重,对亚胺培南/美罗培南耐药率分别为36.0%和38.0%,对其它大多数抗菌药物的耐药率为80%以上;140株多重耐药鲍曼不动杆菌用RAPD分型方法分为8种类型:A～H,其中A、B、C 3型共占70.0%。结论鲍曼不动杆菌耐药性呈上升趋势,且具有多重耐药性;衡阳地区医院感染多重耐药鲍曼不动杆菌可能存在院内的克隆传播。     

替加环素、多粘菌素和头孢哌酮舒巴坦对多重耐药鲍曼不动杆菌体外抗菌活性的研究

目的:研究替加环素、多粘菌素B和头孢哌酮舒巴坦对多重耐药鲍曼不动杆菌体外的抗菌活性,为临床合理用药提供依据。方法:收集2013年1月-2014年6月广东省第二中医院检验科微生物室临床致病菌培养加药敏试验的标本,结果经鉴定为多重耐药鲍曼不动杆菌50株,用药敏纸片扩散法分别对替加环素、多粘菌素和头孢哌酮舒巴坦进行体外药敏试验。结果:替加环素对多重耐药鲍曼不动杆菌保持敏感性100%,对多粘菌素B中介敏感性为67%,对头孢哌酮舒巴坦的耐药率为73%。结论:替加环素、多粘菌素对多重耐药鲍曼不动杆菌有较高的抗菌活性,是临床治疗多重耐药鲍曼不动杆菌感染的最佳药物之一。     

赤芍颗粒剂对泛耐药鲍曼不动杆菌的抗菌活性研究

目的:研究中药赤芍颗粒剂对泛耐药鲍曼不动杆菌的体外抗菌活性,为临床该菌感染引起的感染性疾病的治疗进行探索。方法:收集2013年1月-2014年6月本院检验科微生物实验室的临床致病菌培养加药敏标本,经细菌鉴定和药敏试验符合泛耐药鲍曼不动杆菌的50株株菌,用微量肉汤稀释法药敏试验测定赤芍颗粒剂对该菌株的最小抑菌浓度,观察赤芍颗粒剂的体外抑菌作用。结果:不同浓度的赤芍颗粒溶液对泛耐药鲍曼不动杆菌的OD值均小于阳性对照孔的OD值,并且随着药物浓度的增加,OD值也越来越小,表明赤芍颗粒溶液均有抑制作用,并且随着药物浓度的增加,其抑菌作用越强。结论:赤芍颗粒剂对泛耐药鲍曼不动杆菌在体外抑菌试验中能够抑制它的生长。     

全国27所医院多重耐药鲍曼不动杆菌及铜绿假单胞菌对12种抗菌药物的敏感性

目的　研究医院感染相关多重耐药鲍曼不动杆菌（multi-drug resistant Acinetobacter baumannii,MDR-AB）及多重耐药铜绿假单胞菌（multi-drug resistant Pseudomonas aeruginosa, MDR-PA）对12种抗菌药物的敏感性。方法　收集2011年8月至2012年7月全国27所教学医院分离的医院感染相关MDR-AB及MDR-PA菌株。所有菌株均分离自有明确感染意义的临床标本，严格排除痰及筛查性拭子。菌株收集后统一在微生物实验室采用微量肉汤稀释法，测定其对12种抗菌药物的最小抑菌浓度（minimum inhibitory concentration，MIC），并同时用CLSI M100-S24及M100-S23/S21鲍曼不动杆菌和铜绿假单胞菌的碳青霉烯类新旧折点进行对比分析。结果　本研究共收集到MDR-AB 664株，未发现全耐药鲍曼不动杆菌；收集到MDR-PA 268株，其中有4株全耐药铜绿假单胞菌。外科病房及ICU病房是多重耐药菌株的主要来源。MDR-AB对黏菌素的敏感率最高，为96.8%；替加环素的敏感率为72.6%，其余药物的敏感率均低于55%。MDR-PA对黏菌素的敏感率仅为72.4%，但对阿米卡星的敏感率（64.2%）明显高于MDR-AB（16.7%）。在CLSI折点改变后，MDR-AB对亚胺培南及美罗培南的敏感率仅分别下降了1.3%和0.6%，但MDR-PA对亚胺培南及美罗培南的敏感率分别下降了5.5%和8.6%。ICU病房来源的MDR-AB及MDR-PA对碳青霉烯酶类药物敏感率都明显低于外科及其他病房。不同地域来源多重耐药菌株的耐药谱有所差异。结论　黏菌素和替加环素对MDR-AB有良好的抗菌活性，黏菌素及阿米卡星对MDR-PA抗菌活性较好。     

新型四环素药物Eravacycline体外诱导金黄色葡萄球菌耐药16S rRNA基因突变位点分析

目的:研究Eravacycline体外诱导金黄色葡萄球菌耐药菌株的核糖体30S亚基16S rRNA基因和核糖体蛋白变异特点,阐明金黄色葡萄球菌Eravacycline耐药机制。方法:选择3株金黄色葡萄球菌株,采用Eravacycline不同压力浓度下逐渐诱导Eravacycline耐药金黄色葡萄球菌耐药菌株,挑取诱导菌株单克隆,采用琼脂平板稀释法测定母株及诱导系列的Tigecycline和Eravacycline的MIC值;通过PCR扩增其5个拷贝的16S rRNA基因(RR1-RR5)和30S核糖体蛋白基因,将诱导的Eravacycline耐药株扩增产物测序后与母株序列比较,获得该基因片段突变位点。结果:经过体外Eravacycline不同浓度梯度多步诱导共挑取6株Eravacycline耐药菌株,这些菌株的Tigecycline和Eravacycline的MIC值范围分别为8～16μg/mL和32～64μg/mL。16S rRNA基因PCR测序分析提示该基因的主要突变位点分别为RR1(T170G)、RR2(A1124G,G77A)、RR3(C810T)、RR4(G185A,G1036A),30S亚基核糖体蛋白S3蛋白没有突变,30S亚基核糖体蛋白S10基因多个位点突变。结论:金黄色葡萄球菌Eravacycline诱导耐药后可导致Tigecycline和Eravacycline的交叉耐药及16S rRNA基因和30S亚基核糖体蛋白S10位点突变。     

307例鲍氏不动杆菌的临床分布与耐药性分析

目的:了解分析鲍氏不动杆菌感染的临床分布特点及对各种抗菌药物的耐药性,为临床合理应用抗菌药物及治疗提供科学的依据。方法:回顾性调查2014年1-12月确诊为鲍氏不动杆菌感染的病例,按照全国临床检验规程进行分离,并采用美国临床实验室标准化研究所(CLSI)推荐的K-B法进行药敏试验。结果:共分离出307株鲍氏不动杆菌,来自临床送检的各类标本,以痰标本分离率最高,占90.55%,其次分别是清洁中段尿、分泌物,分别占6.84%、1.63%;鲍氏不动杆菌对米诺环素、头孢哌酮/舒巴坦、美罗培南的耐药率较低,分别为3.91%、5.86%、7.17%;307株鲍氏不动杆菌主要分布于内科系统,其中呼吸内科90株,占29.32%;其次是神经内科62株,占20.20%;老年病科56株,占18.24%;ICU50株,占16.29%;胸外科34株,占11.07%;其他15株,占4.89%。结论:鲍氏不动杆菌是医院感染的常见致病菌之一,应加强鲍氏不动杆菌的耐药性监测,把握其耐药趋势,纠正不合理使用抗生素现象,积极采取有效的控制措施,避免出现泛耐药的超级细菌。     

16S rRNA基因文库对水基泥浆降解菌群的分析

采用SBR法强化驯化对海洋钻井水基泥浆具有一定降解功能的活性污泥菌群,并采用16S rRNA基因文库分析法分析其细菌群落的结构.分析结果表明,经SBR法驯化的活性污泥样品中存在着丰富的细菌种类,这些菌种大部分是厌氧菌或兼性厌氧的烃类降解菌,其中以假单胞菌属为代表的优势菌群具有降解长链石油烃的功能;被驯化的菌种还包括硝酸盐还原菌、硫酸盐还原菌和能够降解长链脂肪酸并与产甲烷菌共生的菌种等,促进了反应器中物质和能量的循环流动.     

Relationships between Bacteroides 16S rRNA genetic markers and presence of bacterial enteric pathogens and conventional fecal indicators

Occurrence and prevalence of different bacterial enteric pathogens as well as their relationships with conventional (total and fecal coliforms) and alternative fecal indicators (host-specific Bacteroides 16S rRNA genetic markers) were investigated for various water samples taken from different sites with different degrees of fecal contamination. The results showed that a wide range of bacterial pathogens could be detected in both municipal wastewater treatment plant samples and in surface water samples. Logistic regression analysis revealed that total and human-specific Bacteroides 16S rRNA genetic markers showed significant predictive values for the presence of Escheriachia coli O-157, Salmonella, heat-labile enterotoxin (LT) of enterotoxigenic E. coli (ETEC), and heat-stable enterotoxin for human (STh) of ETEC. The probability of occurrence of these pathogenic bacteria became significantly high when the concentrations of human-specific and total Bacteroides 16S rRNA genetic markers exceeded 10(3) and 10(4) copies/100 mL. In contrast, Clostridium perfringens was detected at high frequency regardless of sampling sites and levels of Bacteroides 16S rRNA genetic markers. No genes related to Shigella spp., Staphylococcus aureus and Vibrio cholerae were detected in any samples analyzed in this study. Conventional indicator microorganisms had low levels of correlation with the presence of pathogens as compared with the alternative fecal indicators. These results suggested that real-time PCR-based measurement of alternative Bacteroides 16S rRNA genetic markers was a rapid and sensitive tool to identify host-specific fecal pollution and probably associated bacterial pathogens. However, since one fecal indicator might not represent the relative abundance of all pathogenic bacteria, viruses and protozoa, combined application of alternative indicators with conventional ones could provide more comprehensive pictures of fecal contamination, its source and association with pathogenic microorganisms.     

Identification of bacterial populations in drinking water using 16S rRNA-based sequence analyses

Intracellular RNA is rapidly degraded in stressed cells and is more unstable outside of the cell than DNA. As a result, RNA-based methods have been suggested to study the active microbial fraction in environmental matrices. The aim of this study was to identify bacterial populations in drinking water by analyzing 16S rRNA-based clone libraries. Hollow-fiber ultrafiltration was used to concentrate bacterial communities from 40 l of tap water collected at 12 different times during three different summer months from a single point-of-use. Total RNA was extracted from the microbial concentrates and used to develop 16S rRNA-based clone libraries. Phylogenetic analyses of 1231 partial 16S rRNA gene sequences showed that difficult-to-classify bacterial sequences were the most predominant clones, representing 57.6% of the sequences analyzed. Within these unclassified clades, most sequences were closely related to sequences retrieved from previous DNA- and RNA-based drinking water studies. Other bacterial groups represented in this study included Proteobacteria, cyanobacteria, Actinobacteria, Bacteroidetes, and Planctomycetes. Overall, the results suggest that these bacterial groups are amongst potentially active bacteria in drinking water. Diversity analyses of clones generated show that while overall diversity is similar amongst the different months, membership changes with respect to time. The results from this study further improve our understanding of the molecular diversity and bacterial population dynamics of drinking water microbial communities. Moreover, these results provide the sequence foundation for the development of molecular assays that target active drinking water bacteria.     

Pyrosequencing of the 16S rRNA gene to reveal bacterial pathogen diversity in biosolids

Given the potential for a variety of bacterial pathogens to occur in variably stabilized sewage sludge (biosolids), an understanding of pathogen diversity and abundance is necessary for accurate assessment of infective risk when these products are land applied. 16S rDNA was PCR amplified from genomic DNA extracted from municipal wastewater residuals (mesophilic- and thermophilic-phased anaerobic digestion (MAD and TPAD), composting (COM)), and agricultural soil (SOIL), and these amplicons were sequenced using massively parallel pyrosequencing technology. Resulting libraries contained an average of 30,893 16S rDNA sequences per sample with an average length of 392 bases. FASTUNIFRAC-based comparisons of population phylogenetic distance demonstrated similarities between the populations of different treatment plants performing the same stabilization method (e.g. different MAD samples), and population differences among samples from different biosolids stabilization methods (COM, MAD, and TPAD). Based on a 0.03 Jukes-Cantor distance to 80 potential bacterial pathogens, all samples contained pathogens and enrichment ranged from 0.02% to 0.1% of sequences. Most (61%) species identified were opportunistic pathogens of the genera Clostridium and Mycobacterium. As risk sciences continue to evolve to address scenarios that include multiple pathogen exposure, the analysis described here can be used to determine the diversity of pathogens in an environmental sample. This work provides guidance for prioritizing subsequent culturable and quantitative analysis, and for the first time, ensuring that potentially significant pathogens are not left out of risk estimations.     

Evaluation of host-specific Bacteroidales 16S rRNA gene markers as a complementary tool for detecting fecal pollution in a prairie watershed

Our ability to identify and eliminate fecal contamination of water, now and in the future, is essential to reduce incidences of waterborne disease. Bacterial source tracking is a recently developed approach for identifying sources of fecal pollution. PCR primers designed by Bernhard and Field [Bernhard, A.E., Field, K.G., 2000a. A PCR assay to discriminate human and ruminant feces on the basis of host differences in Bacteroides-Prevotella genes encoding 16S rRNA. Appl. Environ. Microbiol. 66(10), 4571-4574] and Dick et al. [Dick, L.K., Bernhard, A.E., Brodeur, T.J., Santo Domingo, J.W., Simpson, J.M., Walters, S.P., Field, K.G., 2005. Host distributions of uncultivated fecal Bacteroidales bacteria reveal genetic markers for fecal source identification. Appl. Environ. Microbiol. 71(6), 3184-3191] for the detection of human (HF183), pig (PF163) and ruminant (CF128) specific Bacteroidales 16s rRNA genetic markers were tested for their suitability in detecting fecal pollution in Saskatchewan, Canada. The sensitivity and specificity of these primers were assessed by testing eight raw human sewage samples and 265 feces from 12 different species in Saskatchewan. The specificity of each primer set was ≥94%. The accuracy of HF183 and PF163 to distinguish between the different species was 100%, whereas CF128 cross-reacted with 22% of the pig feces. Occurrence of the host-specific Bacteroidales markers and the conventional indicator Escherichia coli in relation to several enteropathogens was investigated in 70 water samples collected from different sites along the Qu'Appelle River (Saskatchewan, Canada). Human and ruminant fecal markers were identified in 41 and 14% of the water samples, respectively, whereas the pig marker was never detected in the river water. The largest concentrations in E. coli counts were concomitant to the simultaneous detection of HF183 and CF128. Thermotolerant Campylobacter spp., Salmonella spp. and Shiga toxin genes (stx1 and stx2)-positive E. coli (STEC) were detected in 6, 7 and 63% of the water samples, respectively. However, none of the stx positive water samples were positive for the E. coli O157:H7 gene marker (uidA). Odds ratios analysis suggests that CF128 may be predictive for the presence of Salmonella spp. in the river investigated. None of the fecal indicators were able to confidently predict the presence of thermotolerant Campylobacter spp. and STEC.     

Bioremediation of phenol,sulfate sodium,and polycyclic aromatic hydrocarbons by Rhodococcus sp. first time isolated and molecular characterized from aquatic and terrestrial ecosystems

Environmental pollutions are the most significant problem worldwide. Rhodococcus sp. has a high potential for the production of secondary metabolites and degradation activity. This study aims to screen and characterize biodegradable Rhodococcus from Iranian ecosystems. The Rhodococcus isolates were recovered from 90 environmental samples and identified using conventional and molecular methods. The growth rate in the presence of pollutants and chromatography (high-performance liquid chromatography [HPLC]) was used to determine their biodegradation capability. A total of 13 Rhodococcus isolates were characterized from the cultured samples (14.5%) that belonged to seven species. The prevalent species were R. erythropolis (4 isolates; 30.8%), R. atherivorans (3 isolates; 23%), R. ruber (2 isolates; 15.4), and R. zopfii, R. phenolicus, R. equi and R. rhodochrous 1 isolate each. The result showed that these isolates could degrade and consume phenol, polycyclic aromatic hydrocarbon (PAH) and sulfate sodium. Our results showed that the Rhodococcus species have significant potential for bioremediation of diverse types of pollutants. Therefore, more studies are recommended for the biodegradation activity of Rhodococcus.     

Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash

Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U_max) and saturation value constant (K_B) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.     

Biodegradation of 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine by Actinomycetes species,first time isolated and characterized from water,wastewater, and sludge

Biodegradation has been applied to remediate explosives contaminants, and bacteria have a high potential for the degradation of explosives, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT). The present study aims to screen and characterize explosive biodegradable Actinomycetes from water, wastewater, and sludge. Actinomycetes isolates were recovered from 80 environmental samples from diverse environmental resources in explosive contaminated areas of Iran and identified to the genus and species levels using conventional and molecular methods. The growth rate in the presence of pollutants and chromatography was used to determine their biodegradation capability. Twenty-nine isolates (36.25%) of Actinomycetes were characterized from the cultured samples that belonged to 6 genus and 24 validated species. The most prevalent Actinomycetes isolated were genus Mycobacterium with 11 isolates (37.94%), genus Rhodococcus with seven isolates (24.13%), genus Nocardia with four isolates (13.8%), and genus Streptomyces with three isolates (10.33%). Moreover, our results showed that these isolates could degrade and consume 50–80% of RDX and TNT as their sole carbon and energy source. In conclusion, we showed that Actinomycetes from explosive-contaminated areas of Iran could degrade TNT and RDX. Hence, seeking and screening untapped ecosystems that possess unexplored Actinomycetes will increase the chances of discovering the resident microorganism that has been capable of degrading TNT and RDX for application in the bioremediation process. The results of this study can be useful in using intact bacteria in nature to eliminate environmental pollution, which is one of the major environmental problems in the world.     

Effects of the toxin 3-chloroaniline at low concentrations on microbial community dynamics and membrane bioreactor performance

The effects of toxins at ambient concentrations on microbial activity and community dynamics are poorly understood. We operated 4 membrane bioreactors (MBRs) in parallel; two reactors were continuously exposed to the toxin 3-chloroaniline (3-CA) at environmentally relevant levels, representing 25% of the total chemical oxygen demand (COD; Total COD = 400 mg l⁻¹ d⁻¹), and two reactors received no 3-CA. During the 70 d exposure to 3-CA the microbial communities never adapted as evidenced by a 48% and 14% reduction in COD and ammonia removal, respectively, compared to over 92% reduction for both measurements in the controls. The bacterial 16S rRNA gene was monitored using terminal restriction fragment length polymorphism (T-RFLP) analysis (n = 15 temporal grab samples per reactor) over the 70 d period. T-RFLP spectra analysis compared the rapid species turnover rate (STR) approach with the more computationally intensive non-metric multi-dimensional scaling (NMS) complemented with multi-response permutation procedure (MRPP). The methods revealed comparable findings and the presence of 3-CA selected for a more convergent community with less bacterial turnover. In contrast, the control MBRs were more divergent as evidenced by greater bacterial turnover variability. The importance of studying replicate reactors is highlighted by the fact that one of the two controls was significantly different from the treatment MBRs (p-value = 0.01, α = 0.05) whereas the other one was not (p-value = 0.24, α = 0.05). The study suggests that analysis of community dynamics with the rapid STR approach and with NMS/MRPP can lead to comparable results when targeting the 16S rRNA gene. The use of replicate bioreactors is essential for meaningful interpretation of microbial community patterns.     

Isolation and characterization of a bacterium capable of removing taste- and odor-causing 2-methylisoborneol from water

2-Methylisoborneol (MIB), a metabolite of blue-green algae, has been implicated in causing unpalatable drinking water throughout the world. Current non-biological water treatment technologies are ineffective in removing MIB from potable water or are cost-prohibitive, and biological applications may address these problems. We have isolated and characterized a bacterium derived from lake water and capable of aerobically degrading MIB. Light microscopy and transmission electron microscopy revealed that this strain is a spore-forming, flagellated bacterium that is bacilloid in shape, and 16S rRNA phylogenetic analysis determined that it is most closely related to Bacillus fusiformis and Bacillus sphaericus, both members of the Bacillus sphaericus senso lato taxon. While the growth and oxidation potential of this strain was shown to be affected beyond certain MIB concentrations in the mg/l range, it was capable of depleting MIB at mg/l and ng/l concentrations and of removing MIB to concentrations yielding no observed odor.