Antibiotic resistance rates for Pseudomonas aeruginosa clinical respiratory and bloodstream isolates among the Veterans Affairs Healthcare System from 2009 to 2013

Pseudomonas aeruginosa is a major cause of healthcare-associated infections and resistance among isolates is an increasing burden. The study purpose was to describe national resistance rates for clinical P. aeruginosa respiratory and bloodstream cultures and the prevalence of multidrug-resistant (MDR) P. aeruginosa within the Veterans Affairs (VA). MDR was defined as non-susceptibility to at least one drug in at least 3 of the following 5 categories: carbapenems, extended-spectrum cephalosporins, aminoglycosides, and piperacillin/tazobactam. We reviewed 24,562 P. aeruginosa respiratory and bloodstream isolates across 126 VA facilities between 2009 and 2013. Most isolates were collected from inpatient settings (82%). Resistance was highest in fluoroquinolones (33%) and exceeded 20% for all classes assessed (carbapenems, extended-spectrum cephalosporins, aminoglycosides, and piperacillin/tazobactam). Resistance was higher in inpatient settings and in respiratory isolates. Prevalence of MDR was 20% overall (22% for inpatient isolates, 11% outpatient, 21% respiratory, 17% bloodstream). Our findings are consistent with previous surveillance reports.     

Genetic Diversity,Antibiotic Resistance,and Pathogenicity of Aeromonas Species from Food Products in Shanghai,China

ObjectiveAeromonas has recently been recognized as an emerging human pathogen. Aeromonas-associated diarrhea is a phenomenon occurring worldwide. This study was designed to determine the prevalence, genetic diversity, antibiotic resistance, and pathogenicity of Aeromonas strains isolated from food products in Shanghai.MethodsAeromonas isolates (n = 79) collected from food samples were analyzed using concatenated gyrB-cpn60 sequencing. The antibiotic resistance of these isolates was determined using antimicrobial susceptibility testing. Pathogenicity was assessed using β-hemolytic, extracellular protease, virulence gene detection, C. elegans liquid toxicity (LT), and cytotoxicity assays.ResultsEight different species were identified among the 79 isolates. The most prevalent Aeromonas species were A. veronii [62 (78.5%)], A. caviae [6 (7.6%)], A. dhakensis [3 (3.8%)], and A. salmonicida [3 (3.8%)]. The Aeromonas isolates were divided into 73 sequence types (STs), of which 65 were novel. The isolates were hemolytic (45.6%) and protease-positive (81.0%). The most prevalent virulence genes were act (73.4%), fla (69.6%), aexT (36.7%), and ascV (30.4%). The results of C. elegans LT and cytotoxicity assays revealed that A. dhakensis and A. hydrophila were more virulent than A. veronii, A. caviae, and A. bivalvium. Antibiotic resistance genes [tetE, blaTEM, tetA, qnrS, aac(6)-Ib, mcr-1, and mcr-3] were detected in the isolates. The multidrug-resistance rate of the Aeromonas isolates was 11.4%, and 93.7% of the Aeromonas isolates were resistant to cefazolin.ConclusionThe taxonomy, antibiotic resistance, and pathogenicity of different Aeromonas species varied. The Aeromonas isolates A. dhakensis and A. hydrophila were highly pathogenic, indicating that food-derived Aeromonas isolates are potential risks for public health and food safety. The monitoring of food quality and safety will result in better prevention and treatment strategies to control diarrhea illnesses in China.     

In-vitro activity of the novel fluorocycline eravacycline against carbapenem non-susceptible Acinetobacter baumannii

The activity of eravacycline was compared with that of anti-Acinetobacter reference antimicrobials against carbapenem non-susceptible Acinetobacter baumannii isolates associated with an acquired OXA or up-regulation of the intrinsic OXA-51-like enzyme. Antimicrobial susceptibility testing was performed by broth microdilution of 286 non–duplicate, carbapenem non-susceptible A. baumannii isolates to eravacycline, amikacin colistin, doxycycline, imipenem, levofloxacin, meropenem, minocycline, sulbactam, tigecycline and tobramycin.Eravacycline showed greater activity than the comparators of the tetracycline class, levofloxacin, amikacin, tobramycin and colistin. The eravacycline MIC_50/90 values were 0.5/1?mg/L and those for tigecycline, minocycline and doxycycline were 1/2, 4/8 and 32/?≥?64?mg/L, respectively. In conclusion, eravacycline was the most potent antibiotic of those tested against A. baumannii, including isolates that were resistant to sulbactam, imipenem/meropenem, levofloxacin and amikacin/tobramycin. Eravacycline has the potential to become a useful addition to the limited armamentarium of drugs that can be used to treat this problem pathogen.     

Impact of multidrug resistance on the management of bacterial infections in cirrhosis

Patients with cirrhosis have an increased risk of infection and differently from other complications, that over the years are improving in their outcomes, infections in cirrhotic patients are still a major cause of hospitalization and death (up to 50% in-hospital mortality). Infections by multidrug-resistant organisms (MDRO) have become a major challenge in the management of cirrhotic patients with significant prognostic and cost-related impact. About one third of cirrhotic patients with bacterial infections is infected with MDR bacteria and their prevalence has increased in recent years. MDR infections have a worse prognosis compared to infections by non-resistant bacteria because they are associated with lower rate of infection resolution. An adequate management of cirrhotic patients with infections caused by MDR bacteria depends on the knowledge of some epidemiological aspects, such as the type of infection (spontaneous bacterial peritonitis, pneumonia, urinary tract infection and spontaneous bacteremia), bacteriological profile of antibiotic resistance at each health care unit and site of infection acquisition (community acquired, healthcare associated or nosocomial). Furthermore, regional variations in the prevalence of MDR infections determine that the choice of empirical antibiotic therapy must be adapted to the local microbiological epidemiology. Antibiotic treatment is the most effective measure to treat infections caused by MDRO. Therefore, optimizing antibiotic prescribing is critical to effectively treat these infections. Identification of risk factors for multidrug resistance is essential to define the best antibiotic treatment strategy in each case and the choice of an effective empirical antibiotic therapy and its early administration is cardinal to reduce mortality. On the other hand, the supply of new agents to treat these infections is very limited. Thus, specific protocols that include preventive measures must be implemented in order to limit the negative impact of this severe complication in cirrhotic patients.     

Antimicrobial activity of some essential oils against oral multidrug–resistant Enterococcus faecalis in both planktonic and biofilm state

ObjectiveTo evaluate some essential oils in treatment of intractable oral infections, principally caused by biofilm of multidrug-resistant Enterococcus faecalis (E. faecalis), such as persistent endodontic infections in which their treatment exhibits a real challenge for dentists.MethodsTen chemically analyzed essential oils by gas chromatography-mass spectrometry were evaluated for antimicrobial activity against sensitive and resistant clinical strains of E. faecalis in both planktonic and biofilm state using two methods, disk diffusion and broth micro-dilution.ResultsStudied essential oils showed a good antimicrobial activity and high ability in E. faecalis biofilm eradication, whether for sensitive or multidrug-resistant strains, especially those of Origanum glandulosum and Thymbra capitata with interesting minimum inhibitory concentration, biofilm inhibitory concentration, and biofilm eradication concentration values which doesn't exceed 0.063%, 0.75%, and 1.5%, respectively.ConclusionsFindings of this study indicate that essential oils extracted from aromatic plants can be used in treatment of intractable oral infections, especially caused by biofilm of multidrug-resistant E. faecalis.     

多药耐药基因MDR1在大肠癌的表达及意义

目的探讨多药耐药基因(MDR1基因)在大肠癌组织中的表达及其与临床病理的关系。方法应用RT-PCR方法检测了93例手术切除大肠癌组织中的MDR1 mRNA。结果MDR1 mRNA的阳性率为37.63%,MDR1基因的表达与年龄、性别、肿瘤大小、组织学类型、淋巴结转移及Dukes分期等无关。结论化疗前大肠癌组织中MDR1基因即存在较高的表达率,且独立于病理形态学之外。提示化疗前要区别对待,对MDR1基因表达阳性者应合理选择化疗。     

非M3型急性白血病患者中MUC1基因和MDR1基因表达及其与临床疗效的关系

背景与目的:MUC1基因在胃癌、卵巢癌、多发性骨髓瘤、恶性淋巴瘤等肿瘤中有表达,在急性白血病患者中有较高的表达。但MUC1基因和多药耐药基因(MDR1)相互关系以及两者的表达与急性白血病治疗效果的关系尚有待探讨。本研究拟探讨MUC1基因与MDR1基因表达及其与非M3型急性白血病患者治疗效果的关系。方法:应用逆转录鄄聚合酶链反应(RT鄄PCR)法检测34例初治非M3型急性白血病患者MUC1和MDR1的表达,并观察两种基因表达及其与临床疗效的关系。结果:34例初治非M3型急性白血病患者中MUC1基因阳性率为50%,MDR1基因阳性率为29.4%。MUC1基因阳性患者的MDR1阳性率为52.9%,明显高于MUC1阴性者的5.9%(P=0.003)。MUC1基因阴性者完全缓解(CR)率达94.1%,阳性患者CR率52.9%,两组有显著性差异(P<0.05);MDR1基因阴性者CR率为91.7%,明显高于阳性患者的50.0%(P<0.05)。MUC1基因和MDR1基因均阳性者CR率为55.6%,MUC1基因和MDR1基因均阴性者16例,全部获得CR。结论:非M3型急性白血病MUC1基因阳性者MDR1基因表达率较高,MUC1基因及MDR1基因均为阴性者治疗缓解率高。提示联合检测MUC1基因和MDR1基因对判断初治非M3型急性白血病的疗效有良好的预测作用,可作为临床判断疗效的一项有意义的指标。     

气单胞菌研究概况

气单胞菌在自然界分布广泛,除引发鱼类疫病外也可导致人体不同部位的感染,东南亚国家是腹泻病相对高发的地区,对肝胆外科术后病例有较高的机会性感染和疾病负担;全球耐药特征呈上升趋势,多重耐药（MDR）和超广谱-内酰胺酶（ESBLs）菌株与水产养殖业的抗生素过度使用后环境污染有关;不同地域气单胞菌的毒力因子存在差异。有关部门应制定措施控制水源、食品与养殖环境,降低肠道和非肠道感染的疾病负担。     

板蓝根活性成分对肝癌耐药细胞耐药性的逆转作用研究

目的　研究板蓝根提取物对人肝癌耐药细胞株BEL - 74 0 4 /ADM耐药逆转作用及其逆转机制。方法　用人肝癌细胞株BEL - 74 0 4 /ADM筛选出板蓝根活性单体 ,进行耐药逆转试验 ;使用高效液相色谱仪 (HPLCA)测定细胞内药物含量 ,来探讨其逆转机制。结果　 (1)板蓝根活性单体 5b在高浓度 (>5 0 0 μg/ml)时对亲本细胞及耐药细胞均有细胞毒作用 ,抑制率大于 5 0 % ,在非细胞毒剂量 (<2 5 0 μg/ml)与阿霉素合用后能逆转BEL - 74 0 4 /ADM对阿霉素的耐药性 ,逆转倍数为 2～ 6倍 ;(2 )阿霉素与 5b合用时细胞内阿霉素含量较单独应用时明显升高 (P <0 0 0 1) ,分别为 5 6 .875± 9 349pg和 19 6 2 5± 0 .6 2 9pg。 结论　板蓝根活性单体 5b在非细胞毒剂量范围内能逆转BEL - 74 0 4 /ADM对阿霉素的耐药性 ,其逆转作用可能与降低 p - gp药物外排功能、增加细胞内药物浓度有关     

Modulation of doxorubicin-toxicity by tamoxifen in multidrug-resistant tumor cells in vitro and in vivo

Modulation of the resistance of tumors offers new strategies to improve the therapeutical treatment of cancer. In this report, the anti-oestrogen tamoxifen was investigated in multidrug-resistant tumor cells in vitro and in vivo. The doxorubicin-resistance of L 1210/DOX-tumor cells, which express the multidrug-resistance phenotype, could be completely circumvented by addition of 1 g/ml tamoxifen. In contrast, no increased effect could be observed in the parental L 1210 tumor cells or in cytosine arabinoside-resistant L 1210 cells not expressing the multidrug-resistance phenotype. Thus, the enhancing effect of tamoxifen was restricted only to the multidrug-resistant L 1210/DOX tumor cells. Similar to the in vitro experiments, a significant reduction in the growth in solid tumors of mice by the combined treatment of doxorubicin and tamoxifen was again observed only in the multidrug-resistant L 1210/DOX tumors.