应用E-test法、肉汤微量稀释棋盘法检测泛耐药鲍曼不动杆菌的试验

目的 比较E-test法和肉汤微量稀释棋盘法(CB法)检测体外联合药敏试验并与时间杀菌曲线对比的观察.方法 选择31株泛耐药(PDR)鲍曼不动杆菌临床株进行体外试验,分为替加环素、可立其丁、亚胺培南、阿米卡星单用和两药组合,亚胺培南+替加环素+阿米卡星三药组合也由CB法测试.这些测试的结果与时间杀菌曲线进行比较.结果 亚胺培南+可立其丁、替加环素+亚胺培南能检测到协同作用.培养基中加入抗菌药物的E-test法联合药敏试验与时间杀菌曲线更具有可比性.在三药组合中由CB法和时间杀菌曲线可以检测到协同作用.结论 结果表明联合药敏试验中协同作用测试可以预测特定的抗生素组合对泛耐药鲍曼不动杆菌的作用.     

An Update on Technical,Interpretative and Clinical Relevance of Antimicrobial Synergy Testing Methodologies

Testing for antimicrobial interactions has gained popularity in the last decade due to the increasing prevalence of drug-resistant organisms and limited options for the treatment of these infections. In vitro combination testing provides information, on which two or more antimicrobials can be combined for a good clinical outcome. Amongst the various in vitro methods of drug interactions, time-kill assay (TKA), checkerboard (CB) assay and E-test-based methods are most commonly used. Comparative performance of these methods reveals the TKA as the most promising method to detect synergistic combinations followed by CB assay and E-test. Various combinations of antimicrobials have been tested to demonstrate synergistic activity. Promising results were obtained for the combinations of meropenem plus colistin and rifampicin plus colistin against Acinetobacter baumannii, colistin plus carbapenem and carbapenem plus fluoroquinolones against Pseudomonas aeruginosa and colistin/polymyxin B plus rifampicin/meropenem against Klebsiella pneumoniae. Antagonism was detected in only few instances. The presence of synergy or antagonism with a combination seems to correlate with minimum inhibitory concentration of the agent and molecular mechanism involved in the resistance. Further studies need to be conducted to assess the utility of in vitro testing to predict clinical outcome and direct therapy for drug-resistant organisms.     

氢氧化钙与二甲亚砜对粪肠球菌联合抗菌作用的实验观察

目的：研究氢氧化钙和二甲亚砜对粪肠球菌体外联合药敏实验中的相互作用及联合后化学性质的变化。方法：参照美国国家临床试验标准化委员会（NCCLS）提出的标准，采用棋盘试管稀释法对粪肠球菌进行了氢氧化钙与二甲亚砜体外联合药敏实验并检测了其pH值变化。结果：氢氧化钙与二甲亚砜联合时对粪肠球菌的抑菌浓度分数指数（FICI）=0．8，从羟基离子的角度考虑时，对粪肠球菌的FICI=0．35。氢氧化钙对粪肠球菌的最低抑菌浓度（MIC）=3．5mg／mL，相应pH=10．03，最低杀菌浓度（MBC）=4．5mg／mL，相应pH=11．05，二甲亚砜对粪肠球菌的MIC=20％，相应pH=7．50，MBC=40％，相应pH=8．20。结论：氢氧化钙与二甲亚砜体外联合对粪肠球菌的联合抗菌作用表现为协同相加作用，无拈抗作用。     

Comparisons of bacterial patterns present at implant and tooth sites in subjects on supportive periodontal therapy. I. Impact of clinical variables, gender and smoking

OBJECTIVE: (I) To compare the oral microflora at implant and tooth sites in subjects participating in a periodontal recall program, (II) to test whether the microflora at implant and tooth sites differ as an effect of gingival bleeding (bleeding on probing (BOP)), or pocket probing depth (PPD), and (III) to test whether smoking and gender had an impact on the microflora. MATERIAL AND METHODS: Data were collected from 127 implants and all teeth in 56 subjects. Microbiological data were identified by the DNA-DNA checkerboard hybridization. RESULTS: PPD> or =4 mm were found in 16.9% of tooth, and at 26.6% of implant sites (P<0.01). Tooth sites with PPD> or =4 mm had a 3.1-fold higher bacterial load than implant sites (mean difference: 66%, 95% confidence interval (CI): 40.7-91.3, P<0.001). No differences were found for the red, orange, green, and yellow complexes. A higher total bacterial load was found at implant sites with PPD> or =4 mm (mean difference 35.7 x 10(5), 95% CI: 5.2 (10(5)) to 66.1 (10(5)), P<0.02 with equal variance not assumed). At implant sites, BOP had no impact on bacterial load but influenced the load at tooth sites (P<0.01). CONCLUSION: BOP, and smoking had no impact on bacteria at implant sites but influenced the bacterial load at tooth sites. Tooth sites harbored more bacteria than implant sites with comparable PPD. The 4 mm PPD cutoff level influenced the distribution and amounts of bacterial loads. The subject factor is explanatory to bacterial load at both tooth and implant sites.     

The lower genital tract microbiota in relation to cytokine-, SLPI- and endotoxin levels: application of checkerboard DNA-DNA hybridization (CDH)

In the present study the lower genital tract microbiota in asymptomatic fertile women (n=34) was identified and quantified by culturing vaginal secretions. Also, vaginal and cervical samples were analyzed by a semiquantitative checkerboard DNA-DNA hybridization technique (CDH) based on genomic probes prepared from 13 bacterial species (Bacteroides ureolyticus, Escherichia coli, Fusobacterium nucleatum, Gardnerella vaginalis, Mobiluncus curtisii ss curtisii, Prevotella bivia, Prevotella disiens, Prevotella melaninogenica, Atopobium vaginae, Lactobacillus iners, Staphylococcus aureus ss aureus, Streptococcus anginosus, and Streptococcus agalactiae). The bacterial species found by either culture or CDH were correlated with proinflammatory cytokines (IL-1 alpha, IL-1 beta, IL-6, IL-8), secretory leukocyte protease inhibitor (SLPI), and endotoxin in the cervicovaginal samples. Grading the women into healthy, intermediate, or bacterial vaginosis (BV) as based on Gram staining of vaginal smears, the viable counts of lactobacilli (L. gasseri) and of streptococci-staphylococci combined were highest in the intermediate group. In BV, particularly the high concentrations of Actinomyces urogenitalis, Atopobium vaginae, and Peptoniphilus harei were noted (>or=10(11) per ml). The total viable counts correlated with both cervical IL-1 alpha and IL-1 beta. A strong negative correlation was observed between L. iners and total viable counts, G. vaginalis, or cervical IL-1 alpha, while it correlated positively with SLPI. Analysis of vaginal and cervical samples from 26 out of the 34 women by CDH showed that anaerobic bacteria were more frequently detected by CDH compared to culture. By this method, A. vaginae correlated with G. vaginalis, and L. iners with S. aureus. With regard to cytokines, B. ureolyticus correlated with both cervical and vaginal IL-1 alpha as well as with cervical IL-8, while F. nucleatum, S. agalactiae, S. anginosus, or S. aureus correlated with vaginal IL-1 alpha. Furthermore, all Gram-negative bacteria taken together, as measured by CDH, correlated with vaginal endotoxin and inversely with vaginal SLPI. The significance of the results is discussed. In summary, mapping of the identity and quantity of vaginal bacterial species and their association with locally produced host innate immune factors will help in defining various types of abnormal vaginal microbiota, developing new ways of assessing the risk of ascending subclinical infections, and in treating them. CDH appears to be a suitable tool for future analyses of large numbers of clinical samples with an extended number of bacterial probes.     

头孢哌酮/舒巴坦(2:1,1:1)联合米诺环素对亚胺培南耐药鲍曼不动杆菌的体外抗菌作用

目的 评价头孢哌酮/舒巴坦(2:1,1:1)与米诺环素(四环素类抗生素)联合用药,对39株临床分离的亚胺培南耐药的鲍曼不动杆菌的体外抗菌效应.方法 将不同浓度2种抗菌药用棋盘法设计,用琼脂稀释法测定不同浓度组合的抗菌药对菌株的最低抑菌浓度(MIC),并计算部分抑菌浓度指数(FICI),判定标准:HCI≤0.5为协同作用;0.54为拮抗作用.结果 2种不同配比的头孢哌酮/舒巴坦同米诺环素联用后,HCI均于0.5～4.0,未观察到协同作用,亦无拮抗作用;2种组合的HCI分布情况相当.结论 2种不同配比的头孢哌酮/舒巴坦同米诺环素联合对本组亚南培南耐药的鲍曼不动杆菌表现为无相关作用.