临床分离的携带TR34/L98H型的耐唑类药物烟曲霉的耐药机制分析

目的对临床分离的耐唑类药物烟曲霉菌株进行耐药机制等相关研究。方法自1例侵袭性曲霉病(IA)患者的肺泡灌洗液(BALF)中分离得到1株烟曲霉,采用美国临床实验室标准化协会(CLSI)M38-A2微量液基稀释法测定伊曲康唑、伏立康唑、泊沙康唑、两性霉素B和卡泊芬净对该菌株的最低抑菌浓度(MIC)/最低有效浓度(MEC),并对该菌株的唑类药物靶酶基因cyp51A进行克隆和序列测定分析,扩增并检测该菌株的9个微卫星标记位点,将其与国际上已经报告的具有相同耐药基因型的烟曲霉菌株进行非加权配对算术平均法(UPGMA)聚类分析。结果伊曲康唑、伏立康唑、泊沙康唑、两性霉素B对该菌株的MIC分别为16、2、0.5和2μg/m L,卡泊芬净对该菌株的MEC为0.25μg/m L。该菌株的cyp51A基因序列中存在启动子区-288~-322位间34 bp串联序列的插入,以及编码区T364A、T960A、T1554A的点突变,分别导致所编码蛋白98位、297位及495位氨基酸的置换(TR34/L98H/S297T/F495I)。微卫星分析显示,该菌株的微卫星分型与先前欧洲国家、亚洲其他国家分离的TR34/L98H/S297T/F495I型菌株不同。结论我们从1例IA患者BALF中分离到对唑类药物耐药的烟曲霉临床菌株,其耐药性是由cyp51A基因启动子区34 bp的串联序列插入结合基因编码区突变所致98位、297位及495位氨基酸置换(TR34/L98H/S297T/F495I)所介导,该菌株是中国所特有的、不同于国际上已描述的对唑类药物耐药的病原性烟曲霉。     

国产伏立康唑对临床分离病原真菌体外抗菌活性研究

目的了解国产伏立康唑对北京和我国其他地区临床分离的常见病原真菌体外抗菌活性。方法分别参照CLSIM27-A2和M38-A方案测定伏立康唑对144株酵母和82株产孢丝状真菌的抗菌活性。受试菌株包括念珠菌114株（含氟康唑获得性耐药白念珠菌）、新型隐球菌20株、阿萨希毛孢子菌10株、曲霉62株（含伊曲康唑耐药曲霉及两性霉素B不敏感曲霉）、镰刀菌10株、尖端赛多孢菌10株。结果伏立康唑对念珠菌（不包括氟康唑耐药和剂量依赖敏感白念珠菌）、新型隐球菌、阿萨希毛孢子菌的MIC50≤0．5mg／L、MIC90≤1mg／L；而对氟康唑获得性耐药白念珠菌MIC50和MIC90均〉16mg／L。对曲霉、尖端赛多孢菌的MIC50≤1mg／L、MIC90≤2mg／L，对镰刀菌的MIC50和MIC90分别为4mg／L和〉16mg／L。结论伏立康唑对多数酵母有较强的体外抗菌活性，尤其是对克柔念珠菌和光滑念珠菌等氟康唑天然耐药菌株。该药对多数产孢丝状真菌也有较好的体外抗菌作用，包括伊曲康唑耐药及两性霉素B不敏感的曲霉以及对多种抗真菌药物耐药的尖端赛多孢菌；但其对氟康唑获得性耐药白念珠菌有一定交叉耐药。     

2种新型抗真菌药物体外抗菌活性分析

目的探讨卡泊芬净、伏立康唑等几种新型抗真菌药物对临床常见念珠菌的体外抗菌活性。方法应用Etest法测定82株念珠菌的最低抑菌浓度(MIC)。结果82株念珠菌对卡泊芬净(CS)、伏立康唑(VO)、伊曲康唑(IT)、氟康唑(FL)、氟胞嘧啶(FU)、两性霉素B(AMB)的MIC90(μg/ml)值依次为0.5、1、8、48、0.094、0.19。11株光滑念珠菌对上述6种抗真菌药物的MIC50(μg/ml)、MIC90(μg/ml)值分别为0.032、0.19;1、16;>32、>32;48、128;0.032、0.032;0.19、0.25。1μg/ml的卡泊芬净、伏立康唑、伊曲康唑分别能抑制95.3%、93.8%、85.4%的念珠菌生长。结论卡泊芬净、伏立康唑在体外较其它唑类抗真菌药有更高的抗菌活性,尤其对光滑念珠菌的活性优于伊曲康唑、氟康唑。     

耐唑类抗真菌药白念珠菌标准菌株的建立与评价

目的 建立耐唑类抗真菌药的白念珠菌(C. albicans)标准菌株,参照《病原微生物菌(毒)种国家标准株评价技术标准》(WS/T 812—2022)要求做好病原微生物菌(毒)种保藏工作,为其他真菌标准菌株的候选提供参考方法。方法 通过菌株表型、鉴定、测试9种抗真菌药物敏感性和耐药基因,评估菌株保存状态下的表型稳定性和活性。结果 菌株经内部转录间隔区(ITS)序列分析和质谱仪(MALDI-TOF MS)鉴定为白念珠菌,连续传代十次仍有稳定的分子生物学特征。该菌株对氟康唑、伏立康唑、伊曲康唑、泊沙康唑的最低抑菌浓度(MIC)分别为16 mg/L、0.5 mg/L、0.5 mg/L和0.5 mg/L,耐药性与ERG11基因双点突变(A114S、Y257H)及编码药物外排泵基因突变(A736V)相关。菌株在–80℃表型稳定至少6个月。结论 本研究建立了耐唑类抗真菌药白念珠菌标准菌株,为白念珠菌感染性疾病的综合防治提供了重要的研究对象和物质基础,对于国家生物安全具有重要的战略意义。     

华东地区新生隐球菌药物敏感性分析

目的探索近年来华东地区分离的新生隐球菌临床株对常用抗真菌药物的体外敏感性。方法采用美国临床实验室标准化协会(CLSI)推荐的M27-A3肉汤微量稀释法检测氟康唑、氟胞嘧啶、两性霉素B、伊曲康唑和伏立康唑对新生隐球菌临床分离株的最低抑菌浓度(MIC)范围,并通过内转录间隔区(ITS)测序法对检测出的耐药和剂量依赖性敏感(SDD)菌株进行进一步鉴定。结果抗真菌药物对96株新生隐球菌的MIC90(MIC范围)为:氟康唑4(0.5~16)μg/m L,氟胞嘧啶4(0.25~64)μg/m L,两性霉素B 0.5(0.03~1)μg/m L,伊曲康唑0.5(0.03~1)μg/m L,伏立康唑0.25(0.03~0.5)μg/m L,所有耐药菌株及SDD菌株的分子鉴定均为新生隐球菌格鲁比变种。结论除伊曲康唑外,华东地区新生隐球菌临床株对抗真菌药物的敏感性高,耐药菌株少,不敏感株以新生隐球菌格鲁比变种为主。     

泰地唑胺对革兰阳性球菌的体外抗菌活性研究

目的研究革兰阳性球菌对新型噁唑烷酮类抗菌药物——泰地唑胺的敏感性,并探讨泰地唑胺不敏感菌株的耐药机制。方法收集1 069株革兰阳性球菌[耐甲氧西林金黄色葡萄球菌(MRSA)202株、甲氧西林敏感金黄色葡萄球菌(MSSA)294株、凝固酶阴性葡萄球菌(CoNS)115株、粪肠球菌206株、屎肠球菌55株、无乳链球菌159株和咽峡炎链球菌群菌株38株]非重复临床分离株。采用微量肉汤稀释法检测所有菌株对泰地唑胺和利奈唑胺的最小抑菌浓度(MIC),分析泰地唑胺和利奈唑胺MIC值的差异,比较2种抗菌药物的抗菌活性;采用聚合酶链反应(PCR)检测泰地唑胺/利奈唑胺不敏感菌株的耐药基因。结果所有葡萄球菌(MIC≤0.5μg/mL)、屎肠球菌(MIC≤0.5μg/mL)和链球菌(MIC≤0.25μg/mL)均对泰地唑胺敏感,粪肠球菌对泰地唑胺的敏感率为94.7%,检测出11株泰地唑胺和利奈唑胺均不敏感粪肠球菌(泰地唑胺MIC=1μg/mL,利奈唑胺MIC=8μg/mL)。泰地唑胺的抗菌活性是利奈唑胺的4～8倍。泰地唑胺/利奈唑胺不敏感菌株只携带optrA基因。结论泰地唑胺作为治疗革兰阳性球菌感染的一种新型抗菌药物,具有较大的应用价值,但携带optrA基因的泰地唑胺不敏感肠球菌值得关注。     

丝状真菌的快速鉴定及药敏试验

目的评估基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术在丝状真菌鉴定中的作用,分析常用抗菌药物对丝状真菌的药敏试验结果。方法收集100株丝状真菌,采用MALDI-TOF MS进行快速鉴定,并与显微镜检查结果进行比对;用E-test法进行丝状真菌药敏试验。结果 MALDI-TOF MS对100株丝状真菌鉴定达到种鉴定水平的有61株(得分≥2.000),达到属鉴定水平的有36株(1.700~1.999),未能鉴定的有3株(1.700);与镜检结果不一致的有1株。两性霉素B对絮状表皮癣菌的90%最低抑菌浓度(MIC_(90))为0.19μg/m L,而对黄曲霉的MIC_(90)32μg/m L。伊曲康唑对断发毛癣菌、犬小孢子菌和絮状表皮癣菌的MIC_(90)均0.38μg/m L,而对黑曲霉的MIC_(90)32μg/m L。氟康唑对大部分受试菌株的MIC_(90)均256μg/m L。伏立康唑和卡泊芬净对烟曲霉、黄曲霉、黑曲霉、红色毛癣菌、断发毛癣菌和犬小孢子菌的MIC_(90)分别≤0.38μg/m L和≤1μg/m L。结论 MALDI-TOF MS技术可快速、准确、高通量检测临床分离的丝状真菌。伏立康唑和卡泊芬净对丝状真菌具有较好的抗菌活性。     

特地唑胺对利奈唑胺不敏感革兰阳性球菌的体外抗菌活性研究

摘要:目的检测利奈唑胺不敏感革兰阳性球菌对新型噫唑烷酮类抗菌药物特地唑胺的敏感性，并探讨特地唑胺不敏感菌株 的耐药机制。方法收集临床分离非重复革兰阳性球菌 170株,包括利奈唑胺耐药头状葡萄球菌46株、利奈唑胺敏感头状葡 萄球菌19株、利奈唑胺不敏感肠球菌55株、利奈唑胺敏感肠球菌12株、甲氧西林耐药金黄色葡萄球菌19株、甲氧西林敏感 金黄色葡萄球菌18株、利奈唑胺耐药金黄色葡萄球菌1株。采用微量肉汤稀释法检测所有菌株对特地唑胺和利奈唑胺的最 小抑茵浓度(MIC),并比较两种药物的抗菌活性。采用PCR结合Sanger测序技术分析特地唑胺不敏感革兰阳性球茵fr、optrA 基因携带情况及23S rRNA V区突变。结果利奈唑胺耐药头状葡萄球茵(MICg0>256 μg/mL)对特地唑胺的MIC 值为4~ 32 ug/mL; 利奈唑胺不敏感肠球菌(MIC值4~ 16 μg/mL)中,特地唑胺的敏感率为10.% ,其MIC值为0.5~2 μg/mL;1株利奈 唑胺耐药金黄色葡萄球菌对特地唑胺敏感，MIC值为0.5μg/mL。特地唑胺对利奈唑胺敏感的金黄色葡萄球茵和肠球茵的 MIC值均为0.5 μg/mL,对利奈唑胺敏感头状葡萄球菌的MIC值为0. 125 μg/mL。耐药基因分析显示，特地唑胺耐药头状葡萄 球菌gfr基因携带率为87.0%(40/46) ,23S rRNA V区G2576T的突变率为100% ;特地唑胺不敏感肠球菌optrA 基因携带率为 85.7% (42/49) ,显著高于特地唑胺敏感株的22.2%( P<0.001);1株利奈唑胺耐药特地唑胺敏感的金黄色葡萄球菌携帶cfr基 因。结论对于利奈唑胺不敏感的革兰阳性球菌,特地唑胺的抗茵活性是利奈唑胺的8~32倍,其耐药机制可能与携带optrA 基因及23S rRNA V区G2576T突变有关。     

改良法输注伊曲康唑注射液降低PICC堵管率的护理

目的探讨改良方法输注伊曲康唑注射液预防PICC堵管的效果。方法设计经PICC输注伊曲康唑注射液的改良方法，在伊曲康唑注射液输注前后，分别用自带专用溶媒2ml进行脉冲式冲管。结果2012年1～12月采取改良方法后，经PICC导管输注伊曲康唑注射液21例患者中，无1例因药物结晶而导致堵管，堵管率0％（0／21），较之前按常规法经PICC输注伊曲康唑注射液导致药物性堵管率85％（6／7）相比显著降低，差异有显著意义（P=0．000）。结论采用改良法经PICC输注伊曲康唑注射液，能有效降低PICC药物性堵管的发生率，是一种较为安全有效的输注方法。     

白色假丝酵母菌耐药性与耐药基因表达及蛋白酶的关系

目的研究呼吸道白色假丝酵母菌耐药性与耐药相关基因表达及细胞外蛋白水解酶的关系。方法用NCCLSM27-A方案中的微量液基稀释法检测99株呼吸道分离的白色假丝酵母菌对氟康唑和伊曲康唑的最小抑菌浓度(MIC),RT-PCR半定量检测耐药相关基因CDR1和MDR1的表达,牛血清清蛋白平板法检测细胞性蛋白酶活力。结果99株菌对氟康唑的耐药率为4%,对伊曲康唑的耐药率为12.1%,CDR1的表达在氟康唑的剂量依赖性敏感组高于敏感组和耐药组(P<0.05),蛋白酶的活力在氟康唑剂量依赖性敏感组高于敏感组(P<0.05)。结论菌株的耐药性除与CDR1的过表达有关外,还与其他耐药机制有关,耐药程度不同的菌株细胞性蛋白酶活力有差别,提示菌株的耐药性与毒力之间可能有关联。     

In vitro activity of isavuconazole against 208 Aspergillus flavus isolates in comparison with 7 other antifungal agents: assessment according to the methodology of the European Committee on Antimicrobial Susceptibility Testing

Aspergillus flavus is the second most common species causing invasive aspergillosis after A. fumigatus. In certain countries like India, Sudan, and Saudi Arabia, A. flavus is most frequently isolated from patients with fungal rhinosinusitis and endophthalmitis. A. flavus exhibit an increased resistance to antifungal agents compared to A. fumigatus. We determined the in vitro activity of isavuconazole, voriconazole, posaconazole, itraconazole, amphotericin B, caspofungin, micafungin, and anidulafungin against 208 isolates of A. flavus by the EUCAST method and compared with the results obtained by the CLSI method. Isavuconazole and voriconazole MICs were ≤2 μg/mL in 99% and 95%, respectively. Posaconazole and itraconazole MICs were ≤0.5 and ≤1 μg/mL, respectively, for all isolates. MICs of amphotericin B were ≥2 μg/mL in 91%; 36% of them exhibited MICs of ≥8 μg/mL. All echinocandins demonstrated good anti-A. flavus activity. The essential agreement of the MIC/MEC results by EUCAST with CLSI broth dilution method assessed at ±2 dilutions was good for itraconazole (97.8%), voriconazole (100%), posaconazole (98.3%), isavuconazole (98.9%), caspofungin (99.4%), and anidulafungin (100%), but poor for amphotericin B (53.5%) and micafungin (79.1%).     

In vitro activity of a novel broad-spectrum antifungal, E1210, tested against Aspergillus spp. determined by CLSI and EUCAST broth microdilution methods

E1210 is a first-in-class broad-spectrum antifungal that suppresses hyphal growth by inhibiting fungal glycophosphatidylinositol (GPI) biosynthesis. In the present study, we extend these findings by examining the activity of E1210 and comparator antifungal agents against Aspergillus spp. by using the methods of the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) to test wild-type (WT) as well as amphotericin B (AMB)-resistant (-R) and azole-R strains (as determined by CLSI methods). Seventy-eight clinical isolates of Aspergillus were tested including 20 isolates of Aspergillus flavus species complex (SC), 22 of A. fumigatus SC, 13 of A. niger SC, and 23 of A. terreus SC. The collection included 15 AMB-R (MIC, ≥ 2 μg/ml) isolates of A. terreus SC and 10 itraconazole-R (MIC, ≥ 4 μg/ml) isolates of A. fumigatus SC (7 isolates), A. niger SC (2 isolates), and A. terreus SC (1 isolate). Comparator antifungal agents included anidulafungin, caspofungin, amphotericin B, itraconazole, posaconzole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparators. The essential agreement (EA; ± 2 log(2) dilution steps) was 100% for all comparisons with the exception of posaconazole versus A. terreus SC (EA = 91.3%). The minimum effective concentration (MEC)/MIC(90) values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, and voriconazole, respectively, were as follows for each species: for A. flavus SC, 0.03, ≤ 0.008, 0.12, 1, 1, and 1; for A. fumigatus SC, 0.06, 0.015, 0.12, >8, 1, and 4; for A. niger SC, 0.015, 0.03, 0.12, 4, 1, and 2; and for A. terreus SC, 0.06, 0.015, 0.12, 1, 0.5, and 1. E1210 was very active against AMB-R strains of A. terreus SC (MEC range, 0.015 to 0.06 μg/ml) and itraconazole-R strains of A. fumigatus SC (MEC range, 0.03 to 0.12 μg/ml), A. niger SC (MEC, 0.008 μg/ml), and A. terreus SC (MEC, 0.015 μg/ml). In conclusion, E1210 was a very potent and broad-spectrum antifungal agent regardless of in vitro method applied, with excellent activity against AMB-R and itraconazole-R strains of Aspergillus spp.     

A comparative study of the in vitro susceptibilities of clinical and laboratory-selected resistant isolates of Aspergillus spp. to amphotericin B, itraconazole, voriconazole and posaconazole (SCH 56592)

We investigated the in vitro susceptibilities of clinical and laboratory-selected Aspergillus spp. to posaconazole, and compared the results with those obtained for amphotericin B, itraconazole and voriconazole. Conidial suspensions from clinical isolates (284 Aspergillus fumigatus, 66 Aspergillus niger, 31 Aspergillus flavus and 43 Aspergillus spp.) and laboratory-selected resistant A. fumigatus isolates (15 resistant to amphotericin B, 25 to itraconazole and 12 to voriconazole) were prepared and their susceptibilities to various antifungal agents determined using a previously described broth macrodilution technique. The geometric mean MICs (mg/L) of posaconazole for A. fumigatus (0.17 +/- 0.11) and non-A. fumigatus aspergilli (0.16 +/- 0.28) were significantly lower (P 0.05) than those for amphotericin B, itraconazole and voriconazole. Amphotericin B-resistant A. fumigatus isolates were as susceptible to posaconazole as the parental strain. Itraconazole- and voriconazole-resistant isolates showed low-level (two- to three-fold increase in MICs) cross-resistance to posaconazole. The minimum fungicidal concentrations (mg/L) of posaconazole for A. fumigatus (n = 58) and non-A. fumigatus aspergilli (n = 40) were 4. 45 +/- 2.70 (range 0.25-8) and 4.14 +/- 3.03 (range 0.5-8), respectively. Time-kill studies showed that the fungicidal activity of posaconazole against A. fumigatus is time- and concentration-dependent (for example, posaconazole 4 mg/L killed >99% of A. fumigatus conidia within 24 h). These results suggest that overall, posaconazole has better activity and a smaller range of MICs for Aspergillus spp., including those with reduced susceptibility to amphotericin B, itraconazole and voriconazole.     

Antifungal activities of posaconazole, ravuconazole, and voriconazole compared to those of itraconazole and amphotericin B against 239 clinical isolates of Aspergillus spp. and other filamentous fungi: report from SENTRY Antimicrobial Surveillance Program, 2000

Posaconazole, ravuconazole, and voriconazole are new triazole derivatives that possess potent, broad-spectrum antifungal activity. We evaluated the in vitro activity of these investigational triazoles compared with that of itraconazole and amphotericin B against 239 clinical isolates of filamentous fungi from the SENTRY Program, including Aspergillus spp. (198 isolates), Fusarium spp. (7 isolates), Penicillium spp. (19 isolates), Rhizopus spp. (4 isolates), Mucor spp. (2 isolates), and miscellaneous species (9 isolates). The isolates were obtained from 16 different medical centers in the United States and Canada between January and December 2000. In vitro susceptibility testing was performed using the microdilution broth method outlined in the National Committee for Clinical Laboratory Standards M38-P document. Overall, posaconazole was the most active compound, inhibiting 94% of isolates at a MIC of < or = 1 microg/ml, followed by voriconazole (91%), amphotericin B (89%), ravuconazole (88%), and itraconazole (70%). All three new triazoles demonstrated excellent activity (MIC, < or = 1 microg/ml) against Aspergillus spp. (114 Aspergillus fumigatus, 22 Aspergillus niger, 13 Aspergillus flavus, 9 Aspergillus versicolor, 8 Aspergillus terreus, and 32 Aspergillus spp.): posaconazole (98%), voriconazole (98%), ravuconazole (92%), amphotericin B (89%), and itraconazole (72%). None of the triazoles were active against Fusarium spp. (MIC at which 50% of the isolates tested were inhibited [MIC(50)], >8 microg/ml) or Mucor spp. (MIC(50), >8 microg/ml). Posaconazole and ravuconazole were more active than voriconazole against Rhizopus spp. (MIC(50), 1 to 2 microg/ml versus >8 microg/ml, respectively). Based on these results, all three new triazoles exhibited promising activity against Aspergillus spp. and other less commonly encountered isolates of filamentous fungi. The clinical value of these in vitro data remains to be seen, and in vitro-in vivo correlation is needed for both new and established antifungal agents. Surveillance efforts should be expanded in order to monitor the spectrum of filamentous fungal pathogens and their in vitro susceptibility as these new antifungal agents are introduced into clinical use.     

Comparison of voriconazole (UK-109,496) and itraconazole in prevention and treatment of Aspergillus fumigatus endocarditis in guinea pigs.

Left-sided Aspergillus fumigatus endocarditis was established in the guinea pig heart by catheterization and inoculation with conidia via a tributary of the femoral vein. This animal model was used to compare the efficacy of the triazole antifungal agents voriconazole (UK-109,496) and itraconazole. In the prophylaxis experiments, voriconazole at a dosage of 10 mg/kg of body weight given intraperitoneally twice daily prevented A. fumigatus endocarditis in all but 1 animal (11 of 12 animals were cured). Itraconazole did not prevent Aspergillus endocarditis when it was given at the same dosage and by the same route (0 to 12 animals were cured). In the treatment experiments with 10 animals per group, voriconazole at 10, 7.5 and 5 mg/kg given orally twice daily for 7 days produced cure rates of 100, 70 and 0%, respectively. In contrast, itraconazole at 10 mg/kg given orally twice daily did not cure A. fumigatus endocarditis in the guinea pig. It is concluded that voriconazole is highly efficacious in the prevention and treatment of Aspergillus endocarditis in the guinea pig and is superior to itraconazole in these respects.     

In vitro activities of three licensed antifungal agents against spanish clinical isolates of Aspergillus spp

The aim of the present study was to identify retrospectively trends in the species distributions and the susceptibility patterns of Aspergillus species causing fungal infections in Spanish medical centers from 2000 to 2002. The susceptibilities of 338 isolates to amphotericin B, itraconazole, and voriconazole were tested. Aspergillus fumigatus was the most common species (54.7%), followed by Aspergillus terreus (14.8%) and Aspergillus flavus (13.9%). Non-A. fumigatus species were encountered in 45.3% of the samples studied. The majority of Aspergillus isolates were obtained from respiratory tract specimens, followed by ear and skin samples. The geometric mean (GM) MIC of amphotericin B was 0.56 micro g/ml, and the amphotericin B MIC was >2 micro g/ml for 16 isolates (4.7%). Nine of them were A. terreus. The GM MIC of itraconazole was 0.37, and the itraconazole MIC was >4 micro g/ml for 12 (3.5%) isolates. The voriconazole MICs were also high for 8 of the 12 strains for which itraconazole MICs were high (voriconazole MIC range, 2 to 8 micro g/ml).     

In vitro activity of a new triazole BAL4815, the active component of BAL8557 (the water-soluble prodrug), against Aspergillus spp

OBJECTIVES: BAL4815 is the active component of the antifungal triazole agent BAL8557 (the water-soluble prodrug). We compared the in vitro activity of BAL4815 with that of itraconazole, voriconazole, caspofungin and amphotericin B against 118 isolates of Aspergillus comprising four different species (fumigatus, terreus, flavus and niger); the isolates were pre-selected to include 16 isolates demonstrating in vitro resistance to other agents. METHODS: Susceptibilities were determined for BAL4815, amphotericin B, itraconazole and voriconazole using the microdilution plate modification of the NCCLS M38-A method with RPMI 1640 buffered to pH 7.0 with MOPS; for caspofungin the method was modified using incubation in a gas mixture of 1% O2/5% CO2/94% N2 to aid reading. MFCs (> or =99% kill) were also determined for all drugs other than caspofungin. RESULTS: For all isolates, geometric mean (GM) MIC values and ranges (in mg/L) were: BAL4815, 0.620 and 0.125-2.0; itraconazole, 0.399 and 0.063->8.0; voriconazole, 0.347 and 0.125-8.0; caspofungin, 0.341 and 0.125-4.0; amphotericin B, 0.452 and 0.06-4.0. No significant differences in susceptibility to BAL4815 were seen between species and in contrast to itraconazole no isolates demonstrated MICs >2.0 mg/L. For all isolates, GM MFC values and ranges (in mg/L) were: BAL4815, 1.68 and 0.25->8.0; itraconazole, 1.78 and 0.06->8.0; voriconazole, 1.09 and 0.25->8.0; amphotericin B, 0.98 and 0.25->4.0. CONCLUSIONS: BAL4815 demonstrated promising antifungal activity against all four Aspergillus species in vitro including strains resistant to itraconazole, caspofungin or amphotericin B.     

Studies of in vitro activities of voriconazole and itraconazole against Aspergillus hyphae using viability staining

The minimal fungicidal concentrations (MFCs) of voriconazole and itraconazole for five clinical isolates each of Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger were determined by a broth macrodilution method. Conidial suspensions as inocula were compared to hyphae as inocula since the invasive form of aspergillosis is manifested by the appearance of hyphal structures. In addition, cell viability staining with the dye FUN-1 was performed to assess time-dependent damage of hyphae exposed to various concentrations of the antifungal agents. With conidial inocula the MFC ranges of voriconazole were 0.5 to 4 microg/ml and those of itraconazole were 0.25 to 2 microg/ml, whereas the MFCs (2 to >16 microg/ml) with hyphal inocula were substantially higher (P < 0.01) for both itraconazole and voriconazole. Only minor differences between the tested antifungals were observed since 16 of 20 and 17 of 20 of the isolates of Aspergillus spp. tested appeared to be killed by voriconazole and itraconazole, respectively. The results of FUN-1 viability staining correlated closely to colony counts, but various time- and dose-dependent levels of viability of hyphae were also observed. In conclusion, our study demonstrates the importance of the type of inoculum used to test antifungals and the applicability of FUN-1 staining as a rapid and sensitive method for assaying the viability of hyphae.     

Correlation between the E test and the CLSI M-38 A microdilution method to determine the activity of amphotericin B, voriconazole, and itraconazole against clinical isolates of Aspergillus fumigatus

The in vitro activities of amphotericin B, itraconazole, and voriconazole against 283 clinical isolates of Aspergillus fumigatus were studied by comparing the E test method with the reference procedure NCCLS (CLSI) M-38A. The methods were considered to agree when the results of the MICs by E test were within +/-2 dilutions of the MICs obtained by CLSI M-38 A. Agreement of readings at 24, 48, and 72 h of incubation was as follows: amphotericin B: 4.2%, 98%, and 40.6%; itraconazole: 92.5%, 100%, and 89.9%; and voriconazole: 98.9%, 100%, and 99.7%. The correlation between methods to classify the strains as "susceptible" or "resistant" was very good for itraconazole and voriconazole after 48 h of incubation, but 23% of the strains were incorrectly classified by E test for amphotericin B. The E test is an efficacious method for antifungal susceptibility testing in A. fumigatus for itraconazole and voriconazole when the plates are read after 48 h of incubation. The use of the E test to study the activity of amphotericin B should be avoided.     

Antifungal susceptibility of 596 Aspergillus fumigatus strains isolated from outdoor air, hospital air, and clinical samples: analysis by site of isolation

We analyzed the activities of six antifungal drugs (amphotericin B, itraconazole, voriconazole, posaconazole, caspofungin, and micafungin) against 596 Aspergillus fumigatus strains isolated from outdoor air, hospital air, and clinical samples. We did not find differences among the susceptibilities by site of isolation.