两种方法测定替加环素对鲍曼不动杆菌药敏结果的比较

目的：比较采用两种方法测定替加环素对鲍曼不动杆菌药敏结果的差异。方法：分别采用琼脂平板稀释法和微量肉汤稀释法测定替加环素对70株鲍曼不动杆菌的MIC值,比较其结果差异性。结果：应用琼脂平板稀释法测定的MIC50和MIC90为1μg·mL-1和2μg·mL-1,敏感率、中介率、耐药率分别为47.1%、48.6%、4.3%;应用微量肉汤稀释法测定的替加环素对鲍曼不动杆菌的MIC50和MIC90分别为0.25μg·mL-1和0.5μg·mL-1,敏感率为100%。两种方法测定结果的一致性和相关性均较差;以微量肉汤稀释法为基准时,应用琼脂平板稀释法测定的总误差率为52.9%。结论：应用琼脂平板稀释法和微量肉汤稀释法进行替加环素对鲍曼不动杆菌药敏测定时,其敏感率有明显的差别。     

多黏菌素B药敏条在肠杆菌科药敏检测中应用研究

目的 使用微量稀释法和E-test法分析肠杆菌科细菌对多黏菌素B体外敏感性，评估E-test法多黏菌素B药敏条在临床药敏检测中的价值。方法 收集了887株临床肠杆菌科细菌，同时采用E-test法和微量稀释法进行体外药敏试验，考察两种方法的一致性，针对不一致的进行复测，复测仍不一致者判为不一致，对两种检测方法进行统计学分析。结果 887株菌的平行检测中，842株用药敏条和微量稀释法测定MIC值在|±1|个稀释倍数的范围内，有45株菌的最低抑菌浓度(minimal inhibitory concentration, MIC)值超出了此范围，复测有8株菌的MIC值回到了|±1|个稀释倍数的范围内，即纠正后的EA(essential agreement)%为95.94%(851/887)。肠杆菌科内按照种属分析，EA值最高的为沙门菌属的97.09%(100/103)，EA最低的为其他属肠杆菌的94.03%(126/134)，统计学分析，不同属间无显著性差异。结论 多黏菌素B药敏条用于肠杆菌科细菌检测药敏检测所测定的MIC值判定结果准确可靠，与CLSI推荐的微量稀释法的符合率在94%以上，能满足临床和实验室药敏检测需求。     

微量平板稀释法测定血清杀菌活性的方法学研究

目的:采用微量平板稀释法测定血清杀菌活性(SBA)。方法:选择Mueller Hinton肉汤(MHB)为稀释剂、控制隔夜培养的菌悬液光度在108～109cfu/mL,以微量平板稀释法和琼脂平板计数法分别测定头孢哌酮钠对金黄色葡萄球菌ATCC25923,大肠埃希氏菌ATCC25922,铜绿假单胞菌ATCC27853三种标准质控菌的血清杀菌活性,并测定头孢哌酮钠对三种标准质控菌的SBA的天间和天内重现性。结果:微量平板稀释法与琼脂平板稀释法测定的结果相似,SBA中位数经秩和检验差异无统计学意义(P>0.05)。微量平板稀释法测定的结果天内、天间差异均无统计学意义。结论:微量平板稀释法测定SBA方法简便、易行,实验结果稳定、可靠,具有可行性。     

改良琼脂培养基稀释法在抗真菌药物体外敏感性试验中的应用研究

目的:初步观测改良琼脂培养基稀释法和微量液体培养基稀释法在测定白色念珠菌对伊曲康唑体外敏感性上的差异.方法:采用CLSI M27-A2推荐的微量液体培养基稀释法和改良琼脂培养基稀释法同时测定20株临床近期分离无重复白色念珠菌对伊曲康唑的体外敏感性.结果:两种方法对检测的20株真菌的体外最小抑菌浓度一致.结论:改良琼脂培养基稀释法有可能成为一种评价抗真菌药物体外敏感性的一种直观、简单、快速的方法.     

前列腺液细菌培养及两种药敏实验的比较

前列腺炎的发病率较高,同时也时造成男性尿路反复发作的因素之一,所以前列腺炎的治疗中抗菌素的选择起着关键作用。我们分别用微量稀释法和琼脂扩散法对所分离的菌株进行药敏,比较两种方法的差异,以便为临床准确的选择抗生素提供可靠的科学依据。     

耐碳青霉烯肺炎克雷伯菌对多黏菌素B体外敏感性检测方法的差异性研究

摘要：目的 了解不同检测方法在耐碳青霉烯肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae, CRKP)对多黏菌素 B体外药敏检测中的差异,为临床治疗和实验室检测提供依据。方法 选择2018-2020年宁波地区临床分离的CRKP 147株,分 别采用肉汤稀释法、E-test纸片法、仪器法(N335药敏卡)和纸片法检测其体外对多黏菌素B的敏感性,分析4种药敏检测方法所 存在的差异。结果 微量肉汤稀释法、E-test法和仪器检测CRCP对多黏菌素B MIC50分别为1、1和0.5μg/mL,MIC90分别为1、 1和0.5,累积敏感率分别为97.3%、99.3%和98%,具有较高一致性和敏感性;仪器法检测CRKP对多黏菌素B的平均MIC值为 (0.82±0.16)μg/mL,明显低于标准方法的(1.39±0.27)μg/mL,差异有统计学意义(P＜0.01);E-test法和仪器法的基本一致率(EA) 为92.5%和94.6%,标准符合(CA)分别为97.3%和98.6%,严重错误(VME)分别为2.7%和1.4%;重大错误(ME)和小错误(mE)均为 0;纸片法KB值与肉汤稀释法MIC值之间方差分析P＞0.05,故提示KB值与MIC值不具有线性关系。结论 4种方法检测CRKP 对多黏菌素B体外具有较高敏感性;仪器法和E-test法对于多黏菌素B的敏感性检测与微量肉汤稀释法高度一致,但其中仪器法 N335药敏卡检测MIC有所降低,建议标准方法复核。     

采用最低抑菌浓度筛选氧氟沙星滴眼液处方的初步研究

本文应用琼脂稀释法，测定不同组方的氧氟沙星（OFLX）滴眼剂对临床常见致病菌的最低抑制浓度（MIC），并与相同浓度的市售氧氟沙星滴眼剂的MIC值比较，得出不同组方的氧氟沙星的MIC值各不相同。附加剂的选择对药效有很大的影响。提示处方筛选中MIC测定，需引起重视。     

肚痛丸体外抗菌活性的测定

目的；对肚痛丸提取液进行体外抗菌试验，测定其MIC值，方法：采用琼脂稀释法进行体外抗菌活性的实验。结果：测得肚痛丸提取液体外对肠道常见细菌的最低抑菌浓度（MIC）为0．156－1．250mg/ml，结论：肚痛丸提取液对肠道常见细菌具有显著的抗菌作用。     

头孢他啶/舒巴坦体外抗菌作用研究

目的：评价不同配比头孢他啶／舒巴坦及其对照药的体外抗菌作用。方法：MIC的测定采用琼脂二倍稀释法，MBC的测定采用肉汤二倍稀释法。结果：对革兰阴性菌，头孢他啶／舒巴坦有较好的抗菌效果，其作用与头孢哌酮／舒巴坦相当，优于哌拉西林／他佐巴坦和阿莫西林／克拉维酸。尤其对大肠杆菌、阴沟肠杆菌、枸橼酸菌属和不动杆菌属，酶抑制剂舒巴坦的加入明显提高了头孢他啶对其耐药菌的抗菌效果。对革兰阳性菌，头孢他啶／舒巴坦的作用与头孢哌酮／舒巴坦相当，逊于哌拉西林／他佐巴坦和阿莫西林／克拉维酸。1：1与2：1两配比间无明显差别。细菌接种量和培养基中加入血清蛋白对头孢他啶／舒巴坦的体外抗菌作用无影响，培养基pH值在碱性侧（pH8.5)其活性略有下降而在酸性侧（pH5.0)增强。结论：头孢他啶／舒巴坦为一强效杀菌药。     

耐碳青霉烯肺炎克雷伯菌对替加环素不同体外药敏试验方法学评估

目的 比较不同药敏试验方法检测替加环素对耐碳青霉烯肺炎克雷伯菌(CRKP)的敏感性。初步了解辽宁地区CRKP对替加环素的耐药情况，为临床合理用药提供依据。方法 回顾性收集辽宁省内多家大型三甲医院2011年1月-2016年12月分离的CRKP共269株，采用微量肉汤稀释法、KB纸片扩散法、Vitek-2仪器法及E试验法检测替加环素对CRKP的敏感性。结果 微量肉汤稀释法、E试验法、Vitek-2仪器法测定替加环素MIC50和MIC90分别为(0.5/1)、(0.25/0.5)和(0.5/4)μg/mL。按美国食品与药品监督管理局(FDA)和欧洲药敏试验委员会(EUCAST)判读标准，微量肉汤稀释法测得CRKP对替加环素的敏感率为97.4%/93.3%，中介率为2.2%/4.1%，耐药率为0.4%/2.6%。E试验法敏感率最高，为100%/98.9%，Vitek-2法耐药率最高，为8.6%/13.4%，纸片扩散法的中介率最高，为11.9%/46.5%。与微量肉汤稀释法比较，E试验法的基本一致率(EA)和分类一致率(CA)均≥90%，但存在重大误差(VME)，分别为0.4%/1.9%；Vitek-2法EA仅为61.7%，CA为87.4%/72.1%，且大误差(ME)为6.3%/7.4%，无VME；纸片扩散法CA仅为85.9%/46.5%，小误差(mE)为1.9%/2.6%，ME为0.7%/5.6%。结论 辽宁地区绝大多数CRKP对替加环素仍保持较高的敏感性。对于CRKP、E-试验法、Vitek-2仪器法和纸片扩散法均不适合单独检测替加环素敏感性，可考虑联合检测，若结果不一致，均应参考微量肉汤稀释法。     

Comparison of the Etest and the NCCLS-approved agar dilution method to detect metronidazole and clarithromycin resistant Helicobacter pylori

Although the NCCLS has approved the agar dilution method as the test of choice for antimicrobial susceptibility testing of Helicobacter pylori, a critical evaluation of this method in clinical trials to detect antibiotic resistance has not been performed. This study compares the Etest and agar dilution methods for detection of metronidazole and clarithromycin resistance in clinical isolates of H. pylori. MIC data were gathered from US-based clinical trials. The Etest was performed on Mueller-Hinton sheep blood agar plates following incubation for 4 days under 12% CO(2). The agar dilution test was performed according to the recently approved NCCLS methodology using aged sheep blood in a Mueller-Hinton agar base. Metronidazole resistance as determined by Etest was significantly higher than that determined by agar dilution (39%; 690/1768 vs. 25. 1%; 367/1465)(P<0.01). Clarithromycin resistance as determined by Etest was higher than that determined by agar dilution, but was not significantly different (12.5%; 209/1671 vs. 10.6%; 150/1414)(P>0.5). Inter-patient metronidazole resistance showed that the MIC values for identical isolates tested by both methods were equivalent in 58% (109/188). Of the 42% with a >2log(2) difference in MIC values, 17. 6% had a change in susceptibility pattern. For clarithromycin, 71.4% (237/332) of the MIC values for identical isolates tested by both methods had equivalent MIC values. Of the MIC values with a >2log(2) difference in MIC values, only 3% showed a change in susceptibility pattern. Intra-patient variability, i.e. paired isolates from the same patient, was assessed only for metronidazole. Of the 1393 paired isolates tested by Etest, 38.8% were shown to be resistant. Almost 69% of the Etest MIC determinations were deemed equivalent and 16.7% had a change in susceptibility pattern. Of the 639 paired isolates tested by agar dilution, 23.9% were resistant to metronidazole. Almost 72% of the agar dilution MIC values were equivalent and 11.3% of the determinations had a change in susceptibility pattern. Clarithromycin resistance rates are similar, when determined by either test method. The Etest yields a significantly higher prevalence of metronidazole resistance among H. pylori compared with the agar dilution method and both methods yield discordant results, when isolates from different parts of the same stomach are compared. Neither method is reliable in determining metronidazole resistance in H. pylori.     

Comparison of Etest, agar dilution, broth microdilution and disk diffusion methods for testing in vitro activity of levofloxacin against Staphylococcus spp. isolated from neutropenic cancer patients

The susceptibility to levofloxacin of 194 consecutive staphylococcal (45 Staphylococcus aureus and 149 coagulase-negative staphylococci) isolates from neutropenic patients was determined by Etest and the results compared with those obtained using NCCLS-methods (broth microdilution, agar dilution and disk diffusion). Overall agreement at +/- 1log(2) dilution for Etest compared with broth microdilution and agar dilution was 99.0 and 83.5%, respectively. The Etest category agreement with broth microdilution and disk diffusion was 95.9 and 89.7%, respectively. Comparison of categories with Etest and agar dilution method gave only 67.0% absolute categorical agreement, with 29.9% minor errors and 10.7% major errors. No very major errors occurred by the four methods tested. Our results show that Etest is a valid alternative to the reference NCCLS-methods for monitoring the clinical usefulness of levofloxacin against staphylococci isolates from neutropenic patients.     

头孢吡肟对革兰阴性杆菌的体外敏感性分析及方法评价

目的调查昆明医学院第一附属医院2007年8月至12月301株临床常见革兰阴性杆菌对第4代头孢菌素头孢吡肟的耐药状况,评价采用的MICROSCAN细菌鉴定药物敏感系统中快速接种法的准确性。方法用琼脂稀释法、纸片扩散法、标准浊度法和MICROSCAN快速接种法测定头孢吡肟对301株细菌的体外抑菌活性。以琼脂稀释法为标准参考方法,比较其他3种方法与其结果的一致性。结果琼脂稀释法测定301株革兰阴性杆菌对头孢吡肟的体外总敏感率为78.07%;纸片扩散法、标准浊度法和MICROSCAN快速接种法与标准参考方法的一致率分别为99.00%,98.34%和95.35%。纸片扩散法、标准浊度法检查结果与琼脂稀释法无统计学差异（P〉0.05）,MICROSCAN快速接种法检查结果与琼脂稀释法有统计学差异（P〈0.05）。结论头孢吡肟对大部分临床常见革兰阴性杆菌具有良好的体外抗菌活性,纸片扩散法及标准浊度法结果准确性较高,MICROSCAN快速接种法的准确性有待进一步探讨。     

Preliminary susceptibility testing guidelines for AZD2563, a long-acting oxazolidinone

Rapid expansion of antimicrobial resistance has led to the development of new antimicrobial agents. AZD2563 is a novel oxazolidinone that has activity similar to linezolid and the potential for extended dosing intervals. Recent Gram-positive clinical organisms (1572 strains) were tested including four oxazolidinone-resistant enterococci. Strains processed were: 313 Staphylococcus aureus, 299 coagulase-negative staphylococci, 305 enterococci, 305 Streptococcus pneumoniae, 300 other streptococci (beta-haemolytic and viridans group) and 50 other rarely isolated Gram-positive species. The methods (agar and broth dilution, disk diffusion) of the National Committee for Clinical Laboratory Standards (NCCLS; M7-A6, M2-A8) were followed and linezolid was used as a control agent. A tentative MIC breakpoint (or=20 mm), intermediate at 4 mg/l (17-19 mm) and resistant at >or=8 mg/l (相似文献   

Comparative antimicrobial spectrum and activity of BMS284756 (T-3811, a desfluoroquinolone) tested against 656 Enterobacteriaceae, including preliminary in vitro susceptibility test comparisons and development

BMS284756 (T-3811), a novel des-F(6)-quinolone, was evaluated using isolates of Enterobacteriaceae from the SENTRY Antimicrobial Surveillance Program tested by Etest (AB BIODISK, Solna, Sweden), reference broth microdilution and disk diffusion (5-microg) methods. Ciprofloxacin, levofloxacin, gemifloxacin and gatifloxacin were also tested by broth microdilution as comparator antimicrobial agents within the same drug class. The 656 isolate collection included species from the genera Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Morganella, Pantoea, Proteus, Providencia, Salmonella, and Serratia. BMS284756 was slightly less active than comparison fluoroquinolones against these isolates (MIC(90), 4 mg/l versus 0.06-2 mg/l). However, at a proposed susceptible breakpoint of < or =4 mg/l, 90.7% of the isolates processed were susceptible to BMS284756, demonstrating an equivalent spectrum of activity to all other agents except gemifloxacin (86.6%). In general, isolates requiring >4 mg/l of BMS284756 for inhibition of growth were also less susceptible to the comparators suggesting cross-resistance is common between des-F(6)- and fluoro-quinolones. Excellent correlation was observed between broth microdilution MIC results and 5-microg disk zone diameters (r=0.94), and between broth microdilution dilution and Etest MIC values (r=0.96). In conclusion, BMS284756 has an activity and spectrum similar to contemporary fluoroquinolones and in vitro test methods (NCCLS, Etest) appear accurate and reproducible     

A novel colorimetric broth microdilution method to determine the minimum inhibitory concentration (MIC) of antibiotics and essential oils against Helicobacter pylori

Helicobacter pylori infections have been associated with the pathogenesis of a number of stomach and gastroduodenal diseases. In order to find alternative drugs for their treatment the search is increasingly focused on new antimicrobial products. However, no standardized methods are available to test the anti-Helicobacter pylori activity in particular of natural substances. Therefore we developed a broth microdilution assay to investigate the susceptibility of this fastidious slow growing bacterium against 15 essential oils widely used to treat disorders of the gastrointestinal tract. The MIC values were determined colorimetrically using p-iodonitrophenyltetrazolium violet (INT) as an indicator for bacterial cell viability. The test sytem was evaluated with three common antibiotics: amoxicillin, ampicillin and levofloxacin. The antibiotic MICs were controlled by Etest. The Helicobacter reference strain was remarkably susceptible to both the antibiotics (amoxicillin MIC: 0.02 microg/ml, ampicillin MIC: 0.064 microg/ml, levofloxacin MIC: 0.39 microg/ml) and the essential oils. Most of their MICs ranged from 0.015 to 0.064% (v/v) and about 140.0 to 280.0 microg/ml, respectively. Interestingly, chamomile oil, orange flower oil and ginger oil inhibited the bacterial growth in extraordinarily low concentrations of 0.0075% (v/v) and about 65 microg/ml, respectively. The bactericidal concentrations were generally one to two dilution steps higher. In conclusion, we could develop an innovative assay for the MIC determination of essential oils and antibiotics against Helicobacter pylori, which is simple to handle, accurate, reproducible and not as time- and material-consuming as traditional agar dilution techniques.     

Antimicrobial susceptibility testing of pathogenic Escherichia coli using non-standard conditions

Results of non-standardized disc agar diffusion and broth microdilution antimicrobial susceptibility tests on blood culture isolates of Escherichia coli were compared with those of standardized tests. Test incubation at 40 degrees C, versus 35 degrees C, did not significantly affect results for either method. However, anaerobic incubation significantly altered results for several antimicrobials in both testing methods. The implications of these alterations will be discussed in the text.     

Screening of new bioactive materials from microbial extracts of soil microorganism (I) antimicrobial activity from 200 samples using microdilution assay

The microdilution assay recommended by NCCLS (National Committee for Clinical Laboratory Standards) is one of the standardized methods of antibiotic susceptibility test. This method has been widely used clinically to obtain MIC values of antibiotics on pathogenic microorganisms. It is more convinient, rapid and simple to test many samples than other test methods such as agar diffusion assay and broth macrodilution assay. The screening of antimicrobial agents from microbial extracts is too laborious in its process. Therefore, a number of screening methods having more simple procedure have been developed. In our laboratory, we applied microdilution assay for screening the antimicrobial agents. This assay showed dose-response results and was more sensitive than disc diffusion assay in our system. We tested 200 samples of microbial extracts originated from 100 microbial strains and selected several samples as potential candidates. In this report, we show that the microdilution assay is more convenient method in screening of antibiotic susceptibility than those previously reported.