阴沟肠杆菌AmpC酶的检测及耐药性分析

目的了解某医院阴沟肠杆菌产AmpC酶情况及其对10种常用抗菌药物的耐药性,以指导临床合理选择抗菌药物。方法收集该院2007年8月-2008年7月临床分离的非重复阴沟肠杆菌98株,采用头孢西丁纸片扩散法进行AmpC酶初筛,酶提取物三维试验确证阴沟肠杆菌高产AmpC酶,聚合酶链反应检测AmpC酶基因。以K B纸片扩散法进行药敏试验。结果98株阴沟肠杆菌中有36株携带AmpC酶,检出率36.73％。在36株产AmpC酶阴沟肠杆菌中,检测到仅携带DHA基因株6株(16.67%);仅携带ACC基因株20株(55.56%);同时携带ACC和MIR基因株8株(22.22%);同时携带ACC、MIR和FOX基因株2株(5.56%)。产AmpC酶菌株对头孢西丁全部耐药,对第三代头孢菌素、联合抑酶剂、氨曲南、阿米卡星及环丙沙星均有不同程度耐药（44.44%~91.67%）;对头孢吡肟及亚胺培南较敏感,耐药率分别为27.78%、0.00%。结论阴沟肠杆菌AmpC酶携带率高,是导致其对第三代头孢菌素耐药的重要原因;治疗阴沟肠杆菌感染应以药敏检测结果为依据。     

褪黑素／低聚糖对老年人肠道菌群影响的临床研究

目的研究褪黑素／低聚糖（脑白金）对老年人肠道菌群的影响。方法按“保健食品检验与评价技术规范”设计,44例〉60岁老年人随机分为2组,脑白金组服用脑白金（褪黑素／低聚糖）,对照组服用安慰剂（淀粉／焦糖色素）,均连服14d。结果服用14d后,脑白金组与安慰剂组比较,脑白金组服用前后自身进行比较,双歧杆菌及乳杆菌均增加,差异有统计学意义（P〈0.05,P〈0.01）;而拟杆菌与肠杆菌减少,差异均有统计学意义（P〈0.05）。结论脑白金能促进老年人体内有益菌双歧杆菌及乳杆菌的增殖,抑制有害菌拟杆菌和条件致病菌肠杆菌的增殖。     

36例慢性皮肤溃疡创面阴沟肠杆菌药敏分析

目的分析慢性皮肤溃疡创面阴沟肠杆菌对临床常用抗生素的耐药情况。方法对从慢性皮肤溃疡创面分离出的36株阴沟肠杆菌采用美国DADE公司生产的Microscan半自动微生物分析系统,采用Microscan Autoscan-4PC20快速革兰阴性鉴定板,鉴定出细菌。采用Microscan Autoscan-4PC20革兰阴性细菌药敏卡片,得出药敏的敏感程度。结果36例慢性皮肤溃疡患者对阿莫西林/棒酸、氨苄西林、头孢西丁、头孢噻吩耐药率为100%,对亚胺培南敏感率为100%,对阿米卡星敏感率72.4%,对头孢他定敏感率63.8%,对复方新明敏感率为41.7%,对其他多种抗生素呈现高度耐受。结论阴沟肠杆菌对临床常用抗生素药物具有高耐药率和高耐药水平,多重耐药现象较普遍,临床可把喹诺酮类抗生素和阿米卡星作为临床首选;也可以选用头孢他啶和复方新明。亚胺培南是对其最稳定、最可靠的敏感药物,可用于严重病例的治疗。     

Invasive Enterobacter sakazakii disease in infants

Enterobacter sakazakii kills 40%-80% of infected infants and has been associated with powdered formula. We analyzed 46 cases of invasive infant E. sakazakii infection to define risk factors and guide prevention and treatment. Twelve infants had bacteremia, 33 had meningitis, and 1 had a urinary tract infection. Compared with infants with isolated bacteremia, infants with meningitis had greater birthweight (2,454 g vs. 850 g, p = 0.002) and gestational age (37 weeks vs. 27.8 weeks, p = 0.02), and infection developed at a younger age (6 days vs. 35 days, p<0.001). Among meningitis patients, 11 (33%) had seizures, 7 (21%) had brain abscess, and 14 (42%) died. Twenty-four (92%) of 26 infants with feeding patterns specified were fed powdered formula. Formula samples associated with 15 (68%) of 22 cases yielded E. sakazakii; in 13 cases, clinical and formula strains were indistinguishable. Further clarification of clinical risk factors and improved powdered formula safety is needed.     

烧伤病房阴沟肠杆菌耐药性研究

目的探讨烧伤病房阴沟肠杆菌的耐药性。方法对我院2001年1月至2004年12月烧伤病房产阴沟肠杆菌的耐药性进行分析。结果57株阴沟肠杆菌对临床常用抗生素耐药性均不同程度增加，只对亚胺培南敏感。结论阴沟肠杆菌同样为烧伤病房常见的院内感染细菌之一，其耐药性不容乐观。临床应根据药敏试验选用抗菌药物，控制院内感染。     

利用产气肠杆菌EAM-Z1转化合成5-氟尿苷的转化率影响因素的研究

利用产气肠杆菌EAM Z1转化合成5 氟尿苷,从筛选中间体稳定剂、底物流加、底物诱导、菌体冻融和石英砂研磨等方面研究转化率的影响因素,结果:(1)转化过程中加入40 mmol/L的硼砂可以将转化率达到75.56%,提高30.28%;加入10 mmol/L的甘氨酸可以使转化率达到61.92%,提高6.76%;(2)流加5 氟尿嘧啶可以将转化率提高到87.78%;(3)培养过程中加入尿苷诱导效果并不明显,尿苷浓度为 0.001 g/L时效果最佳,提高3.63%;(4)菌体冻融和石英砂研磨使转化率下降26%。     

Prevalence of extended-spectrum β-lactamases in isolates of the Enterobacter cloacae complex from German hospitals

In 2002, 119 isolates of the Enterobacter cloacae complex were collected randomly from 11 German laboratories nationwide. Antibiotic susceptibilities were tested by disk-diffusion tests according to CLSI guidelines, and MICs were determined using Etests. PCRs were performed to amplify all TEM and SHV, and most CTX-M and OXA beta-lactamase genes. PCR products were sequenced to identify the precise extended spectrum beta-lactamase (ESBL) types. Isoelectric focusing (IEF) and PM/PML Etests were used to confirm production of the respective ESBLs. According to susceptibility tests and CLSI criteria, 49 (40%) isolates were resistant to extended-spectrum cephalosporins. Seven (5.8%) isolates were positive in at least one of the PCR assays. Sequencing identified production of TEM-1 beta-lactamase genes by three (2.9%) isolates, and ESBL genes of the CTX-M and SHV beta-lactamase families by five (4.2%) isolates. IEF confirmed the production of beta-lactamases in the expected pI ranges of the respective ESBLs, and four of the five ESBL-producers were detected using the PM/PML Etest. All ESBL-producing isolates showed co-resistance to sulphonamides.     

阴沟肠杆菌的诊断噬菌体

以３４株阴汤肠杆菌培养物作为繁殖菌，从３份污水中分离到阴泡杆菌的噬菌体２４株。经测定其裂解谱并经５折的试制应用，在其中选出一株作为阴沟肠杆菌的诊断噬菌体。实验结果表明，Ｅｎｔ噬菌体可裂解阴沟肠杆菌培养物１８９株中的１６４株，对于肠杆菌科其它１４个属种的４１９６析培养物无一发现裂解，具有严格的种特异性。     

Mechanisms of quinolone resistance in clinical isolates of Enterobacter cloacae

Objective: To study and evaluate changes in the gyrA gene and the outer-membrane protein patterns in relation to evolution of resistance against the quinolones in Enterobacter cloacae.
Methods: Strains expressing gyrA -mediated quinolone resistance become susceptible to quinolones upon insertion of the plasmid pNJR3–2. This plasmid (containing wild-type Escherichia coli quinolone-susceptible DNA gyrase A subunits) and pLA2917 (the vector) were introduced into 10 resistant or moderately susceptible clinical isolates of Enterobacter cloacae by conjugation. The transconjugants, the original isolates, the plasmid and the vector control were screened for susceptibility to ofloxacin, ciprofloxacin and sparfloxacin. Additionally, examinations of the outer-membrane proteins were performed.
Results: A reduction of MICs by a factor of 8–32 was found for the transconjugants of five Enterobacter cloacae isolates in the presence of the gene probe, suggesting that these isolates harbored mutations in gyrA. No discernible difference in the patterns of outer-membrane proteins of sensitive and resistant strains could be detected.
Conclusions: It seems that changes in the target site such as alterations in gyrA are important factors leading to a change in the susceptibility of bacteria to the quinolones, whereas there were no evident changes in the outer-membrane proteins to account for evolution of resistance.