Different bactericidal abilities of plasma-activated saline with various reactive species prepared by surface plasma-activated air and plasma jet combinations

Plasma-activated water(PAW),as an extended form of cold atmospheric-pressure plasma,greatly expands the application of plasma-based technology.The biological effects of PAW are closely related to the aqueous reactive species,which can be regulated by the activation process.In this study,surface plasma-activated air(SAA)and a He+O_(2)plasma jet(Jet)were parallelly combined(the SAA+Jet combination)or sequentially combined(the SAA→Jet combination and the Jet→SAA combination)to prepare plasma-activated saline(PAS).The PAS activated by the combinations exhibited stronger bactericidal effects than that activated by the SAA or the Jet alone.The concentrations of H_(2)O_(2)and NO_(2)^(-)were higher in the PAS activated by the Jet→SAA combination,while ONOO^(-)concentrations were close in the three kinds of PAS and^(1)O_(2)concentrations were higher in the PAS activated by the SAA+Jet combination.The analysis of scavengers also demonstrated that H_(2)O_(2),^(1)O_(2),and ONOO^(-)in the PAS activated by the SAA+Jet combination,and^(1)O_(2)in the PAS activated by the Jet→SAA combination played critical roles in bactericidal effects.Further,the effective placement time of the three PAS varied,and the PAS activated by the Jet→SAA combination could also inactivate 2.6-log_(10)of MRSA cells after placement for more than 60 min.The regulation of reactive species in plasma-activated water via different combinations of plasma devices could improve the directional application of plasma-activated water in the biomedical field.

It’s Possible to Predict a Decreased Bactericidal Effect of Biocides, through Antibiotic Resistance in ICU: Study Using a Large Sample of Bacteria and Multivariate Analysis

Objective: To determine whether there was any association between resistance to antibiotics and decreased susceptibility to antiseptics and disinfectants and their importance in clinical practice. Methods: We studied a large number of microorganisms isolated from ICU patients (high percentage of cases of antibiotic resistance). The antibiogram (Kirby-Bauer) was determined and, in parallel, the bactericidal effect was assessed by two methods, according to the product used: 1) Effect on rough material (endodontic files) in 10 min, using five disinfectants;2) Effect on a skin equivalent (sterile cotton cloth) in 30 sec, for two alcohol solutions. A predictive equation of the bactericidal effects versus microorganisms’ antibiogram was obtained by multivariate methods. Results:?Bactericidal efficacy was very similar for all the products with the exception of 1% povidone-iodine. Within each product there were no significant differences between the three groups of microorganisms: “Enterobacteria”, “Non Fermentative Gram Negative Bacteria” and “cocci”. Multivariate study only obtained one significant equation: 1% chlorhexidine resistance was directly correlated with aztreonam resistance (OR = 2.16), while resistance to imipenem and to phosphomycin acted as protection factors (OR < 1). Conclusion: There is no necessary to change the indications for antiseptics or disinfectants in ICUs, except if aztreonam resistance is high. In which caseis better to use greater concentration than 1% of Chlorhexidine.

微酸性电解水-超声波并行联合处理对鲜切生菜表面大肠杆菌杀菌效果的影响

为探明微酸性电解水(slightly acidic electrolyzed water,SAEW)与超声波(ultrasonic,US)并行联合处理对鲜切生菜表面大肠杆菌(Escherichia coli)的杀菌效应,本研究在不同料液比(1∶5、1∶10、1∶15(g/mL))和不同温度(25、35、45℃)条件下采用SAEW-US并行联合处理鲜切生菜,并用平板计数法测定生菜表面E.coli菌落数,对菌落数的变化情况进行协同效应分析及动力学分析。采用流式细胞术和双层培养计数法对处理后的E.coli进行亚致死损伤检测。结果表明,SAEW-US并行联合处理的杀灭E.coli效力高于SAEW单一作用时的杀灭E.coli效力,随着处理时间的延长、溶剂用量的增加和温度的提高,杀灭E.coli效果显著增强。SAEW-US并行联合处理对于杀灭E.coli具有“1+1>2”的协同效应,且杀菌过程遵循一级动力学模型。SAEW-US并行联合处理比单独SAEW处理杀灭E.coli效果强,并且能降低E.coli亚致死损伤数量。综上可知,SAEW-US并行联合处理鲜切生菜表面E.coli存在协同效应,相关结果可为鲜食农产品的杀菌提供理论依据。

纳米硒联合聚维酮碘对手术感染杀菌的效果

【目的】负载多功能纳米硒聚维酮碘(PVP-I@Se)消毒剂对金黄色葡萄球菌(SA)、耐甲氧西林金黄色葡萄球菌(MRSA)的杀菌效果,为皮肤手术部位消毒提供实验依据。【方法】实验分为PVP-I组(对照组)与PVPI@Se组(实验组),两组的碘浓度梯度相同,分别为50、75、100、200和400μg/mL,实验组硒浓度2μg/mL,对照组不添加硒,比较两组不同的消毒液对SA、MRSA的消毒效果,检测指标包括最低抑菌浓度(MIC)和最低杀菌浓度(MBC);碘浓度50μg/mL时的最短杀菌时间;碘浓度200μg/mL、400μg/mL时的抑菌圈大小。【结果】对照组对SA、MRSA的MIC均为79.17μg/mL、实验组分别为54.17和70.83μg/mL。而对照组对SA、MRSA的MBC分别为129.17和150.00μg/mL,实验组分别为70.83和87.50μg/mL。碘浓度50μg/mL时,对照组对SA、MRSA的最短杀菌时间为130 s、140 s,实验组分别为65 s、75 s。碘浓度200μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为7.67 mm、8.33 mm,实验组均为9.50 mm。碘浓度400μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为9.00 mm、9.33 mm,实验组分别为11.67 mm、12.00 mm。【结论】在聚维酮碘浓度为50、75、100、200和400μg/mL时,分别加入浓度为2μg/mL的硒,可增强其对SA、MRSA的杀菌效果、缩短作用时间。硒(SeNPs)加入PVP-I对SA、MRSA的杀菌效果均有增效作用。但增敏效果SA较MRSA显著。MRSA的增效作用对碘浓度(400μg/mL)需求较高。为临床精准选用消毒剂的浓度和作用时间,降低临床皮肤手术部位感染提供理论依据。

低浓度微酸性电解水对纯培养及海虾中副溶血性弧菌与腐败希瓦氏菌的杀灭作用

为探究低浓度微酸性电解水(low concentration slightly acidic electrolyzed water,LcSAEW)对纯培养及海虾中的副溶血性弧菌与腐败希瓦氏菌的杀灭作用,该研究通过平板计数、生长曲线、电导率、膜电位、胞内物质渗漏量、活性氧和显微镜观察分析了LcSAEW对两种细菌的抑菌效果、细胞膜完整性以及细胞形态的影响。结果表明,有效氯浓度为4、8 mg/L的LcSAEW处理纯培养副溶血性弧菌与腐败希瓦氏菌30 s时,菌落数均降低8 lg CFU/mL以上。用10 mg/L的LcSAEW处理接种两种目标菌的海虾10 min后,菌落数分别降低1.6、1.25 lg CFU/mL。LcSAEW处理后,2种细菌的代谢活性和胞内ATP浓度均降低,而电导率、胞外DNA、蛋白质和K^(+)含量均上升。此外,膜电位呈现超极化,胞内活性氧累积,细胞形态出现凹陷、皱缩现象。综上所述,LcSAEW可以破坏细胞结构、细胞膜通透性,导致细菌活性紊乱甚至凋亡。该研究可为LcSAEW在水产品中的应用提供理论依据。

3种消毒剂对猪场4种常见细菌的杀菌效果试验

为了研究聚六亚甲基双胍盐酸盐、过硫酸氢钾复合物、戊二醛-癸甲溴铵在不同作用浓度、不同作用时间对大肠埃希氏菌、葡萄球菌、沙门氏菌以及肺炎克雷伯菌的灭活效果,为猪场选用消毒剂提供参考。采用悬液定量杀菌试验方法,研究3种消毒剂在不同作用浓度、不同作用时间对大肠埃希氏菌、葡萄球菌、沙门氏菌以及肺炎克雷伯菌的灭活效果。结果显示,以杀菌对数值5.00作为评价标准来判断,聚六亚甲基双胍盐酸盐在500mg/L、5min内对大肠埃希氏菌、葡萄球菌、沙门氏菌以及肺炎克雷伯菌的杀灭对数值>5.00;过硫酸氢钾复合物在2000mg/L、5min内对大肠埃希氏菌、葡萄球菌、沙门氏菌以及肺炎克雷伯菌的杀灭对数值>5.00;戊二醛-癸甲溴铵在2000mg/L、10min内对葡萄球菌、沙门氏菌以及肺炎克雷伯菌的杀灭对数值>5.00,大肠埃希氏菌杀灭效果评测试验中,在试验浓度和时间中没有结果显示杀灭对数值5.00。结果表明除了戊二醛-癸甲溴铵对大肠埃希氏菌的杀灭效果相对较差外,3种消毒剂在试验浓度下均具有良好的杀灭细菌繁殖体效果。

复方季铵盐泡沫消毒剂急性毒性和杀菌影响因素评价

为研究复方季铵盐泡沫消毒剂的临床安全使用,本试验从急性经口毒性、皮肤刺激性、眼刺激性和杀菌影响因素4个方面展开初评,对大鼠经口灌胃消毒剂,测定半数致死量(LD_(50)),考察复方季铵盐泡沫消毒剂的毒性;对家兔进行皮肤刺激性试验,考察其对背部完整皮肤的刺激性;对家兔进行眼刺激性试验,考察其经眼睛单次染毒后眼刺激损害的程度;采用悬液定量法测定不同温度和pH对复方季铵盐泡沫消毒剂杀菌效果的影响。结果显示,该消毒剂对雄性和雌性大鼠的LD_(50)分别为7413和5129 mg/(kg·bw);3只雄性家兔染毒后连续14 d,背部皮肤红斑和水肿平均积分(刺激指数)均为0;3只雄性家兔在染毒后1 h以及1、2、3、7、14和21 d,角膜损害、虹膜损害、结膜充血和结膜水肿平均积分均为0。该消毒剂的杀菌效果随着温度的升高明显增强,随pH提高先增强后降低。结果表明,在本试验条件下,复方季铵盐泡沫消毒剂经口毒性为实际无毒,急性皮肤和眼刺激性试验中均表现为无刺激性;该消毒剂的杀菌效果随温度的升高明显增强,在偏碱性条件下杀菌效果更优。本试验结果为复方季铵盐泡沫消毒剂在畜禽场的安全使用提供参考。

某电厂工业水管道在再生水环境中的腐蚀原因

某电厂工业水管道在运行过程中发生了泄漏。采用X射线荧光光谱(XRF)和扫描电子显微镜(SEM),对管道表层和内层腐蚀形貌、腐蚀产物成分进行了分析,采用最大可能计数法(MPN)检测循环水系统中异养菌、硫酸盐还原菌(SRB)、铁细菌(IB)的菌落形成单位(CFU)总数,采用余氯分析仪检测了系统内余氯质量浓度。结果表明:系统异养菌总数超出标准规定,在系统中多个取样点均检出SRB、IB;杀菌剂投加后0.5 h时余氯消耗量占8 h时余氯消耗量的50%以上,定时投加杀菌剂的杀菌效果不满足标准要求;微生物参与腐蚀,在管道内壁形成大量的锈瘤和附着物,Cl-在附着物下富集,发生自催化腐蚀,加剧了金属基体的溶解,最终导致管道泄漏。

222nm远紫外线的杀菌作用及安全性评价

【目的】环境中的病原菌传播是当前疾病防控中亟待解决的难题,传统紫外线(254 nm)是目前环境消毒的主要方式,因其对机体免疫系统、皮肤和眼睛造成不可逆转的损伤而受到限制,故探索一种无间断、安全有效的消毒手段是一项有前景的研究。【方法】选取恶劣的场地考察222 nm远紫外线无间断照射8 h对环境中病原菌的消杀作用,其中阴性对照组不做处理,阳性对照组敞开放置,远紫外组敞开放置的同时用远紫外线距离30 cm进行照射;对临床常见致病菌(金黄色葡萄球菌、枯草芽孢杆菌、铜绿假单胞菌和大肠埃希菌)涂布后连续照射30 min,并设置阴性和阳性对照组,对比远紫外线与传统紫外线灭菌的差异;通过对比照射距离(20、30 cm)和作用时间(15、30、45、60、75、90 s)考察远紫外线对常见致病菌的表面杀菌率并判断其杀菌能力;将常见致病菌接种至液体培养基中,考察远紫外线对液体中细菌的灭菌效果;以222 nm远紫外线无间断照射小鼠8 h后观察其临床状态、血常规和皮肤组织学变化,初步判断远紫外线长时间照射对机体的安全性。【结果】与阴性对照组相比,阳性对照组培养基上观察到多种细菌,而远紫外组培养基上无细菌定植。222 nm远紫外线无间断照射30 min可杀灭金黄色葡萄球菌、枯草芽孢杆菌、铜绿假单胞菌和大肠埃希菌,照射15 s杀菌率即可高达99.9%。距离20 cm照射222 nm远紫外线的杀菌效果普遍优于距离30 cm照射的杀菌效果。液体杀菌效果评价中,远紫外线的灭菌效果欠佳。小鼠安全性试验结果表明,222 nm远紫外线无间断照射小鼠8 h对其临床症状、内脏器官、血常规及皮肤组织无明显影响,而传统紫外可能会对其造成损伤。【结论】222 nm远紫外线对常见致病菌的表面定植有极强的杀灭作用,杀菌率在15 s即可高达99.9%,且照射距离与杀菌效果成正比,但对液体杀菌效果仍有待改进和提升,且连续照射8 h不会对小鼠的临床状态、血常规和皮肤组织学造成明显影响,有良好的安全性,为环境中疾病防控提供了一个新的方案。

The effect of gas additives on reactive species and bacterial inactivation by a helium plasma jet

In this paper,the influences of gas doping(O2,N2,Air)on the concentrations of reactive species and bactericidal effects induced by a He plasma jet are studied.Firstly,results show that gas doping causes an increase in voltage and a decrease in current compared with the pure He discharge under the same discharge power,which might be attributed to the different chemical characteristics of O2 and N2 and verified by the changes in the gaseous reactive species shown in the optical emission spectroscopy(OES)and Fourier transform infrared(FTIR)spectroscopy.Secondly,the concentrations of aqueous reactive oxygen species(ROS)and reactive nitrogen species(RNS)are tightly related to the addition of O2 and N2 into the working gas.The concentrations of aqueous NO-2 and NO-3 significantly increase while the concentrations of aqueous ROS decrease with the admixture of N2.The addition of O2 has little effect on the concentrations of NO-2 and NO-3 and pH values;however,the addition of O2 increases the concentration of O-2 and deceases the concentrations of H2O2 and OH.Finally,the results of bactericidal experiments demonstrate that the inactivation efficiency of the four types of plasma jets is He+O2>He+Air>He>He+N2,which is in accordance with the changing trend of the concentration of aqueous O.-2 Simultaneously to the better understanding of the formation and removal mechanisms of reactive species in the plasma–liquid interaction,these results also prove the effectiveness of regulating the concentrations of aqueous reactive species and the bacteria inactivation effects by gas doping.

Synergistic Effect between Fucoidan and Antibiotics against Clinic Methicillin-Resistant <i>Staphylococcus aureus</i>

Fucoidan is a sulfated polysaccharide that is primarily extracted from brown seaweeds which has been broadly studied in recent years due to its numerous biological properties, including anticoagulant, antithrombotic, antitumor, and antiviral activities. In this study, fucoidan was evaluated against clinic isolated methicillin-resistant Staphylococcus aureus (MRSA) 1 - 20, either alone or with antibiotics, via broth dilution method and checkerboard and time kill assay. Minimum inhibitory concentrations (MICs)/Minimum bactericidal concentrations (MBCs) values for the fucoidan against all the tested bacteria ranged between 64 - 512/256 - 2048 microg/mL, for ampicillin 32 - 1024/64 - 1024 microg/mL and for oxacillin 8 - 64/16 - 256 microg/mL respectively. Furthermore, the MIC and MBC were reduced to one half-eighth as a result of the combination of the fucoidan with antibiotics. 2 - 6 hours of treatment with 1/2 MIC of fucoidan with 1/2 MIC of antibiotics resulted from an increase of the rate of killing in units of CFU/mL to a greater degree than was observed with alone. These results suggest that fucoidan could be employed as a natural antibacterial agent against multi-drug bacteria.

Effect of the Suppression of Cariesitic Bacterial Growth and Biofilm Formation Using Hydrogen/Free Chlorine Mixed Water Produced by an Electrolysis-Type Hydrogen Generator

OBJECTS: Hydrogen has been shown to possess antibacterial effects at high concentrations. In addition, chlorine has a strong bactericidal effect even at low concentrations. Electrolysis is a way to simultaneously generate these two components. However, the concentration of hydrogen/free chlorine mixed water generated through electrolysis decreases quickly. It is predicted that the concentration of hydrogen/free chlorine mixed water will vary depending on the quality of water used. After investigating the optimum generation conditions, the effects of the most stable concentration of hydrogen/free chlorine mixed water on carious tooth fungus were evaluated in vitro. Thus, in this experiment, our goal was to evaluate the effects of hydrogen/free chlorine mixed water on oral bacteria. MATERIALS AND METHODS: Using a device that generates hydrogen/free chlorine through electrolysis, the differences in the concentrations of hydrogen and free chlorine based on electrolysis time were evaluated using tap water. Additionally, various concentration changes due to electrolysis time on the hydrogen/free chlorine mixed water were evaluated. Distilled tap water as a control group, hydrogen/free chlorine mixed water, and commercially available mouthwash were added for 1 minute to cultured Streptococcus mutans and then rinsed out with the culture medium. Bacterial growth (600 nm) and biofilm formation (590 nm) were measured at 3 and 6 hours after the addition of the medium. RESULTS: The concentration of hydrogen/chlorine mixed water produced by electrolysis varied depending on electrolysis time and the water used. The inhibitory effect of bacterial growth was enhanced depending on the chlorine concentration. Regarding the inhibitory effect on biofilm formation, only the mixed water of hydrogen/free chlorine concentration (500 ppb - 1.0 mg/L) had a suppressing effect after 6 hours. CONCLUSION: It was suggested that hydrogen/chlorine mixed water can be easily produced by electrolysis and has the effect of suppressing the growth of dental caries;therefore, it could be used as a cleaning agent in oral care products.

D-氨基酸驱散生物膜的行为与作用机理研究

为了明确D-氨基酸增强杀菌剂的生物膜驱散效果及杀菌机理,采用不同D-氨基酸与传统杀菌剂三丁基正十四烷基氯化膦(TTPC)、四羟甲基硫酸磷(THPS)以及抗菌肽组成复配杀菌剂,通过失重实验、电化学测试、表面分析等手段研究了复配杀菌剂对碳钢表面上的硫酸盐还原菌(SRB)、铁氧化菌(IOB)、SRB+IOB混合菌的杀菌缓蚀效果,明确了D-氨基酸驱散生物膜的行为与作用机理。结果表明:SRB和IOB发生协同作用,在碳钢试样表面形成致密的生物膜,其不仅提供了适合SRB生长的厌氧环境,还对SRB起到一定的保护作用,导致SRB+IOB混合菌造成的腐蚀最为严重,而D-氨基酸释放出的生物膜分散信号因子可改变细菌细胞壁肽聚糖成分以及调节细胞基因表达方式,通过其与细菌蛋白质结合来抑制生物膜形成,并使已有生物膜主动从碳钢表面分散脱落,破坏SRB与IOB所构成的氧浓差环境,在很大程度上抑制了因细菌所产生的胞外聚合物(EPS)导致的金属腐蚀加剧,进而使得杀菌剂能更好地杀灭生物膜下的细菌,对混合菌生物膜中SRB和IOB的杀菌率分别高达100%、82.60%,表明D-氨基酸通过驱散生物膜行为对杀菌剂起到了很好的杀菌增强效果。

大蒜原汁对乳鸽腹泻大肠杆菌的抗菌效果研究

为检测大蒜汁对乳鸽腹泻大肠杆菌的抗菌作用,采用常量试管稀释法检测4种大蒜汁对乳鸽腹泻大肠杆菌的最小杀菌浓度(MBC)和最小抑菌浓度(MIC)。试验结果表明:37℃时紫皮多瓣蒜的MBC为2.5%,MIC为1.25%;白皮多瓣蒜、独头蒜和三瓣蒜的MBC均为5%,MIC均为2.5%。不同温度下,白皮多瓣蒜、三瓣蒜和独头蒜75℃时的MIC分别为2.5%、10%和10%,三者加热到85℃和95℃后均没有抗菌作用;紫皮多瓣蒜在85℃时有一定的抗菌作用,MIC为2.5%,加热到95℃后没有抗菌作用。4种大蒜汁在37℃时对乳鸽腹泻大肠杆菌均具有抗菌作用,对乳鸽腹泻大肠杆菌病具有良好的预防与治疗作用。

屏障系统常用消毒剂对金黄色葡萄球菌的杀菌效果

金黄色葡萄球菌是一种常见的条件性致病菌,能够引发实验动物的化脓性感染,并严重威胁着实验动物的健康与安全。实验动物屏障设施是抵御有害致病菌的重要防线,因此屏障系统的消毒工作是保证实验动物不被金黄色葡萄球菌等致病菌感染的关键。使用消毒剂是杀灭屏障系统中致病菌的有效手段。论文详细介绍了8种屏障系统常用的消毒剂(包括过氧化物类、季铵盐类、醛类、含氯类消毒剂)对金黄色葡萄球菌的杀菌效果及消毒策略,旨在为实验动物屏障系统应用消毒剂防治金黄色葡萄球菌污染提供参考。

不同药剂灌根对欧李根癌病的防治效果试验研究

为探究不同药剂对欧李根癌病的防治效果,采用药剂灌根法,对欧李患病植株进行药剂灌根试验,比较不同药剂对欧李生长指标和根癌病防治效果的影响。结果表明,氢氧化铜+中生菌素对欧李的新梢生长及SPAD值有促进作用,同时对欧李根瘤的生长有一定抑制作用;从对根癌病的防治效果来看,供试杀菌剂中氢氧化铜、根癌灵,以及氢氧化铜+中生菌素对根癌病有一定的治疗作用。

比较5种消毒剂对4种细菌的杀菌效果

目的 验证5种消毒剂对4种SPF级实验动物必须排除的细菌的杀菌效果。方法 以D/E中和肉汤为中和剂,检测其对5种消毒剂的中和作用;通过悬液定量杀菌实验,测试5种消毒剂对金黄色葡萄球菌、铜绿假单胞菌、肺炎克雷伯菌和鼠伤寒沙门氏菌的杀菌效果。结果 D/E中和肉汤对于新洁尔灭、健之素消毒液、百毒杀、百胜-30和75%乙醇均有较好的中和作用。新洁尔灭、健之素消毒液、百胜-30和75%乙醇4种消毒剂分别与4种细菌作用,1.5 min后杀灭效果良好。1∶600倍稀释的百毒杀消毒液有效杀灭金黄色葡萄球菌、肺炎克雷伯菌、沙门氏菌需要5~10 min,但它对铜绿假单胞菌杀菌效果不理想。1∶200倍稀释的百毒杀消毒液作用1.5 min,可以有效杀灭铜绿假单胞菌。结论 新洁尔灭、健之素消毒液、百胜-30和75%乙醇在较短时间内即可对4种细菌产生良好的消毒效果。百毒杀有效杀灭铜绿假单胞菌需要较高浓度。

微酸次氯酸溶液的杀菌效果评价

[目的]评价研制的微酸次氯酸溶液对大肠埃希菌、金黄色葡萄球菌及白色念珠菌的杀菌效果,并初步确定该溶液作为消毒剂使用的最佳浓度及时间,为本品的后续研发及申报新兽用消毒剂提供参考依据。[方法]采用电解法制备微酸性次氯酸溶液,有效氯含量为625 mg/L,pH 6.3。采用中和剂鉴定试验及悬液定量杀菌试验,评价该次氯酸溶液对大肠埃希菌、金黄色葡萄球菌及白色念珠菌的杀菌效果。[结果]中和剂鉴定试验表明,5 g/L硫代硫酸钠对微酸次氯酸溶液具有良好的中和作用,且中和剂及中和产物对试验菌的生长无显著影响。在悬液定量杀菌试验中,10 mg/L次氯酸溶液作用1 min时,对悬液内大肠埃希菌、金黄色葡萄球菌的杀灭率可达到100%,对白色念珠菌无明显杀灭作用;50 mg/L次氯酸溶液作用3 min对白色念珠菌的杀菌率可达100%。[结论]该微酸次氯酸溶液对大肠埃希菌、金黄色葡萄球菌及白色念珠菌均有良好的杀灭效果,初步确定溶液作为消毒剂的最低使用质量浓度为50 mg/L,作用时间不低于3 min。

Assessment of bactericidal role of epidermal mucus of Heteropneustes fossilis and Clarias batrachus (Asian cat fishes) against pathogenic microbial strains

This research was directed to understand the bactericidal effect of epidermal mucus of two Asian cat fish species viz.Clarias batrachus and Heteropneustes fossilis.Epidermal mucus extracts(raw and diluted)of both cat fish species were tested against several Gram negative(Pseudomonas aeruginosa,Escherichia coli,Klebsiella pneumonia,A.hydrophila)and Gram positive bacterial strains(Bacillius cereus,Staphylococcus aureus,S.epidermidis)and antibacterial results were also compared with two standard antibiotics viz.amikacin and chloramphenicol used as positive control.An A.hydrophila challenge experiment was also performed on all selected test fish species to examine the change in the amount of mucus production and its bactericidal impact..Both epidermal mucus extracts(raw and diluted)of all selected normal and bacterial challenged test objects showed potent bactericidal effect against all pathogenic bacterial strains taken under study.However,former was more effective than later.Also raw epidermal mucus extracts of both normal and bacterial challenged cat fish species exhibited significantly higher ZOI values against all selected microbial strains than diluted mucus extracts and antibiotic chloramphenicol.Hence,these outcomes have clearly revealed that this cost effective natural product acquired from fishes is the key component of their defensive system.Therefore,it could be utilized as a novel‘antimicrobial’in human as well as veterinary sector for combating against several bacterial diseases.

微酸性次氯酸水结合乳化剂酪蛋白酸钠对冷鲜肉主要腐败菌的杀菌作用

目的:研究微酸性次氯酸水(slightly acidic hypochlorous water,SAHW)对冷鲜肉主要腐败菌莓实假单胞菌(Pseudomonas fragi)及荧光假单胞菌(Pseudomonas fluorescens)的杀菌作用,提高其对冷鲜肉表面腐败菌的杀菌效果。方法:在研究50 mg/L的SAHW结合0.02%(质量分数,下同)酪蛋白酸钠稳定性(贮存过程中有效氯质量浓度及pH值变化)的基础上,测定SAHW结合0.02%酪蛋白酸钠处理后冷鲜肉体外及体内假单胞菌菌落总数。结果:避光封口贮存方式下的SAHW与酪蛋白酸钠混合液的稳定性最佳。在体外条件下,SAHW对P.fragi和P.fluorescens杀菌作用在不同质量浓度及作用时间下相较于混合液均更强,在SAHW质量浓度为50 mg/L时,SAHW及混合液对P.fragi的致死对数值分别为6.16(lg(CFU/mL))和2.26(lg(CFU/mL)),致死率分别为85.20%和31.26%。体内实验结果显示,50 mg/L SAHW与0.02%酪蛋白酸钠混合液对P.fragi及P.fluorescens致死对数值分别为1.74(lg(CFU/mL))和1.87(lg(CFU/mL)),比SAHW单独处理效果分别提高了55.4%和62.7%。结论:乳化剂的添加提高了SAHW在冷鲜肉体内的杀菌性。