The Activity of Erianin and Chrysotoxine from Dendrobium chrysotoxum to Reverse Multidrug Resistance in B16/h MDR-1 Cells

采用转染上人类ＭＤＲ１基因，对长春花碱及阿霉素具有交叉耐药性的鼠黑色素瘤细胞株对从鼓槌石斛中分得的二个氢芪类化合物毛兰素及鼓槌素的抗肿瘤多药耐药性进行研究。结果表明：二个化合物均能在一定程度上增加阿霉素在多药耐药细胞株中的积累。

REVERSAL EFFECTS OF MIFEPRISTONE ON MULTIDRUG RESISTANCE(MDR) IN DRUG-RESISTANT BREAST CANCER CELL LINE MCF7/ADR IN VITRO AND IN VIVO

To explore the reversal effect of mifepristone on multidrug resistance (MDR) in drug-resistant human breast cancer cell line MCF7/ADR and its mechanisms. Methods: Expression of MDR1 and MDR-associated protein(MRP) mRNA in MCF7/ADR cells was detected using reverse transcription- polymerase chain reaction(RT-PCR). Western blotting was used to assay the protein levels of P-glycoprotein (P-gp) and MRP. Intracellular rhodamine 123 retention and [3H]vincristine (VCR) accumulation were measured by flow cytometry and liquid scintillation counter, respectively. MTT reduction assay was used to determine the sensitivity of cells to the anticancer agent, adriamycin (ADR). Additionally, a MCF7/ADR cell xenograft model was established to assess the reversal effect of mifeprisone on MDR in MCF7/ADR cells in vivo. Results: Miferpristone dose-dependently down- regulated the expression of MDR1 and MRP mRNA in MCF7/ADR cells, accompanied by a significant decrease in the protein levels of P-gp and MRP. After exposure to 5, 10, and 20 mmol/L mifepristone, MCF7/ADR cells showed a 3.87-, 5.81-, and 7.40-fold increase in the accumulation of intracellular VCR(a known substrate of MRP), and a 2.14-, 4.39-, and 5.53-fold increase in the retention of intracellular rhodamine 123(an indicator of P-gp function), respectively. MTT analysis showed that the sensitivity of MCF7/ADR cells to ADR was enhanced by 7.23-, 13.62-, and 20.96-fold after incubation with mifepristone as above-mentioned doses for 96 h. In vivo, mifepristone effectively restored the chemosensitivity of MCF7/ADR cells to ADR. After 8 weeks of administration with ADR(2 mg穔g-1穌-1) alone or in combination with mifepristone(50 mg穔g-1穌-1), the growth inhibitory rate of xenografted tumors in nude mice was 8.08% and 37.25%, respectively. Conclusion: Mifepristone exerts potent reversal effects on MDR in MCF7/ADR cells in vitro and in vivo through down- regulation of MDR1/P-gp and MRP expression and inhibition of P-gp- and MRP-dependent drug efflux, thus increasing the sensitivity to anticancer drug.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells

In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparti- cles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDRl-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope （TEM）. MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration （IC50） ofpaclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control （P〈0.05）. MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC_50 （0.197±0.003, 0.144±0.001, 0.120±0.004） were decreased with difference being significant when compared with that in A2780/TS （0.269±0.003） cells control （P〈0.05）. It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

Mechanisms Efflux Pumps of <i>Acinetobacter baumannii</i>(MDR): Increasing Resistance to Antibiotics

Acinetobacter baumannii has greatly increased its degree of resistance to become multidrug resistant (MDR) over the past 30 years and is on the red line of the most widely replicated bacteria according to World Health Organization (WHO). The efflux pumps are the main cause for the increasing antibiotic resistance of A. baumannii originated from nosocomial infection. The progressive resistance of A. baumannii even on the recent drugs (tigecycline and fosfomycin) reduces to very effective antibiotic scale. With attention focused on MDR and pan-drug-resistant (PDR) in A. baumannii multiple works on efflux pumps chemical inhibitor (NMP, PAβN, omeprazole, verapamil, reserpine, CCCP) are still in progress. Certain inhibitors from plants (Biricodar and timcodar, Falvone, Mahonia, Dalea versicolor, Lycopus europaeus, and Rosmarinus officinalis) have the capability to have such compounds according to their very significant synergistic effect with antibiotics. In this review we focused on the growth of antibiotic resistance to explain the mechanism of efflux pumps into these different super families and a comprehensive understanding of the extrusion, regulation and physiology role of drug efflux pumps in the essential development of anti-resistivity drugs. We recapitulated the evolution of the work carried out in these fields during the last years and in the course of elaboration, with the aim of increasing the chances of decreasing bacterial resistivity to antibiotics.

In Vitro Study of Ultrasound on Multidrug Resistance in MDR Human Hepatoma HepG_2 Cells

OBJECTIVE The aim of the study was to examine the reversal effects of ultrasound(US) on the MDR in HepG2/ADM,a HepG2 cell line resistant to Adriamycin(ADM),and to study the mechanism of US action.METHODS Using the MTT assay,the effects of US on MDR in HepG2/ADR cells were studied.Before and after the treatment with 0.5W/cm2 low intensity ultrasound(LIUS),the expression of the MDR-related genes,mdr1,mrp and lrp was assayed with the reverse transcriptase polymerase chain reaction(RT-PCR)and the levels of their respective protein expression determined by flow cytometry.By using confocal laser scanning microscopy(CLSM),we examined the intracellular daunorubicin (DNR) distribution,and the effects on the cells of treatment with US or DNR. RESULTS LIUS significantly reversed MDR in HepG2/ADR cells.A er treatment with LIUS at 0.5W/cm2,chemosensitivity to ADM and DNR increased 3.35-fold and 2.81-fold,respectively.The reversal activity by LIUS plus verapamil(VER) was stronger than with either US or VER alone.A er treatment with 0.5W/cm2 ,the expression of both the MDR1 and the MRP mRNA genes began to decline(P<0.01 and P<0.05,respectively);the expression of LRP showed no significant changes.Changes in the expression of the P-glycoprotein(P-gp) and MRP were similar to those of their mRNA expressions.Results of the CLSM showed that administration of US(0.5W/cm2) or VER(15.7μM) with DNR to HepG2/ADM cells showed a significant change in the distribution of DNR in the cells. CONCLUSION Our results show that LIUS can reverse MDR. The reversal effects are stronger than those of either US or VER alone,when combined with VER administration.As LIUS is non-invasive causing no toxicity,it might have potential for clinical application.The reversal mechanism needs further study.

PXR、MDR1、CYP3A5和CYP2B6在高级别浆液性卵巢癌组织中的表达及其意义

目的探讨孕烷X受体(PXR)、多药耐药蛋白1(MDR1)、细胞色素P4503A5(CYP3A5)和细胞色素P4502B6(CYP2B6)在高级别浆液性卵巢癌(high grade serous ovarian cancer,HGSOC)组织中的表达及其意义。方法选取2019年9月-2021年12月青岛市市立医院妇科收治的56例HGSOC患者作为试验组,据其对铂类药物的耐药情况分为耐药组(24例)和敏感组(32例),另外选取妇科同期收治的16例子宫肌瘤患者作为对照组。采用免疫组织化学、实时定量荧光PCR及蛋白印迹法对试验组患者HGSOC组织和对照组患者正常输卵管组织中PXR、MDR1、CYP3A5和CYP2B6的表达情况进行检测。结果与对照组相比较,试验组患者PXR、MDR1、CYP3A5、CYP2B6阳性表达率显著升高(χ^(2)=12.879~17.174,P<0.05),mRNA相对表达量显著升高(t=9.746~17.640,P<0.05),蛋白表达量显著升高(t=13.312~60.448,P<0.05);与敏感组相比,耐药组患者PXR、MDR1、CYP3A5、CYP2B6阳性表达率显著升高(χ^(2)=4.371~8.549,P<0.05),mRNA相对表达量显著升高(t=6.859~19.000,P<0.05),蛋白表达量显著升高(t=8.693~27.670,P<0.05)。HGSOC患者PXR与CYP3A5、CYP2B6的表达呈正相关(r=0.332、0.308,P<0.05),与MDR1的表达无明显相关性(P>0.05)。结论PXR、MDR1、CYP3A5、CYP2B6在HGSOC患者的肿瘤组织中呈高表达,其可能参与HGSOC的发生发展过程。PXR、MDR1、CYP3A5和CYP2B6的表达检测可用于判断HGSOC对化疗的敏感性,有助于为术后化疗提供指导意见。

Relationship between Methylation Status of Multi-drug Resistance Protein(MRP) and Multi-drug Resistance in Lung Cancer Cell Lines

Objective： To study the relationship between the methylation status of multi-drug resistance protein （MRP） gene and the expression of its mRNA and protein in lung cancer cell lines. Methods： Human embryo lung cell line WI-38, lung adenocarcinoma cell line SPCA-1 and its drug-resistant cells induced by different concentrations of doxorubicin were treated with restriction endonuclease Eco47III. The methylation status of MRP was examined by PCR, and the expressions of its mRNA and protein were evaluated by in situ hybridization and immunohistochemistry. Results： MRP gene promoter region of WI-38 cells was in hypermethylation status, but the promoter region of MRP in SPCA-1 cells and their resistant derivatives induced by different concentrations of doxorubicin were in hypomethylation status. There were significant differences in the expression of MRP mRNA among WI-38 cell line, SPCA-1 cells and their drug-resistant derivatives induced by different concentration of doxorubicin. Consistently, MRP immunostaining presented similar significant differences. Conclusion： The promoter region of MRP in SPCA-1 lung adenocarcinoma cells was in hypomethylation status. The hypomethylation status of 5＇ regulatory region of MRP promoter is an important structural basis that can increase the activity of transcription and results in the development of drug resistance in lung cancer.

Multidrug resistance associated proteins in multidrug resistance

Multidrug resistance proteins(MRPs) are members of the C family of a group of proteins named ATP-binding cassette(ABC) transporters.These ABC transporters together form the largest branch of proteins within the human body.The MRP family comprises of 13 members,of which MRP1 to MRP9 are the major transporters indicated to cause multidrug resistance in tumor cells by extruding anticancer drugs out of the cell.They are mainly lipophilic anionic transporters and are reported to transport free or conjugates of glutathione(GSH),glucuronate,or sulphate.In addition,MRP1 to MRP3 can transport neutral organic drugs in free form in the presence of free GSH.Collectively,MRPs can transport drugs that differ structurally and mechanistically,including natural anticancer drugs,nucleoside analogs,antimetabolites,and tyrosine kinase inhibitors.Many of these MRPs transport physiologically important anions such as leukotriene C4,bilirubin glucuronide,and cyclic nucleotides.This review focuses mainly on the physiological functions,cellular resistance characteristics,and probable in vivo role of MRP1 to MRP9.

Synthesis and biological evaluation of tetrahydroisoquinoline derivatives as potential multidrug resistance reversal agents in cancer

Tetrahydroisoquinoline derivatives were synthesized and their multidrug resistance reversal activities were evaluated in vitro. The results showed that some of the synthetic compounds had higher multidrug resistance （MDR） reversal activities than verapamil.

Breast cancer resistance protein(BCRP/ABCG2):its role in multidrug resistance and regulation of its gene expression

Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer cells.BCRP physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis barriers.BCRP recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical use.Thus,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer drugs.Because BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor prognosis.Therefore,blocking BCRP-mediated active efflux may provide a therapeutic benefit for cancers.Delineating the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated MDR.Current evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated receptor.Furthermore,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer cells.Finally,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of conditions.These biological events seem involved in a complicated manner.Untangling the events would be an essential first step to developing a method to modulate BCRP function to aid patients with cancer.This review will present a synopsis of the impact of BCRP-mediated MDR in cancer cells,and the molecular mechanisms of acquired MDR currently postulated in a variety of human cancers.

Enhanced anticancer effect of doxorubicin by TPGS-coated liposomes with Bcl-2 siRNA-corona for dual suppression of drug resistance

Multiple drug resistance(MDR)is a tough problem in developing hepatocellular carcinoma(HCC)therapy.Here,we developed TPGS-coated cationic liposomes with Bcl-2 siRNA corona to load doxorubicin(Dox)i.e.,Bcl-2 siRNA/Dox-TPGS-LPs,to enhance anticancer effect of Dox in HCC-MDR.TPGS i.e.,d-α-tocopheryl polyethylene glycol 1000 succinate,inhibited Pglycoprotein(P-gp)efflux pump and Bcl-2 siRNA suppressed anti-apoptotic Bcl-2 protein.The Bcl-2 siRNA loaded in the liposomal corona was observed under transmission electron microscopy.The stability and hemolysis evaluation demonstrated Bcl-2 siRNA/Dox-TPGSLPs had good biocompatibility and siRNA-corona could protect the liposomal core to avoid the attachment of fetal bovine serum.In drug-resistant cells,TPGS effectively prolonged intracellular Dox retention time and siRNA-corona did improve the internalization of Dox from liposomes.In vitro and in vivo anticancer effect of this dual-functional nanostructure was examined in HCC-MDR Bel7402/5-FU tumor model.MTT assay confirmed the IC50 value of Dox was 20–50 fold higher in Bel7402/5-FU MDR cells than that in sensitive Bel7402 cells.Bcl-2 siRNA corona successfully entered the cytosol of Bel7402/5-FU MDR cells to downregulate Bcl-2 protein levels in vitro and in vivo.Bcl-2 siRNA/Dox-TPGS-LPs showed superior to TPGS-(or siRNA-)linked Dox liposomes in cell apoptosis and cytotoxicity assay in Bel7402/5-FU MDR cells,and 7-fold greater effect than free Dox in tumor growth inhibition of Bel7402/5-FU xenograft nude mice.In conclusion,TPGS-coated cationic liposomes with Bcl-2 siRNA corona had the capacity to inhibit MDR dual-pathways and subsequently improved the anti-tumor activity of the chemotherapeutic agent co-delivered to a level that cannot be achieved by inhibiting a MDR single way.

Synergistic Effect of Hyperthermia and Neferine on Reverse Multidrug Resistance in Adriamycin-resistant SGC7901/ADM Gastric Cancer Cells

Multidrug resistance（MDR） plays a major obstacle to successful gastric cancer chemotherapy.The purpose of this study was to investigate the MDR reversal effect and mechanisms of hyperthermia in combination with neferine（Nef） in adriamycin（ADM） resistant human SGC7901/ADM gastric cancer cells.The MDR cells were heated at 42℃ and 45℃ for 30 min alone or combined with 10 μg/mL Nef.The cytotoxic effect of ADM was evaluated by MTT assay.Cellular plasma membrane lipid fluidity was detected by fluorescence polarization technique.Intracellular accumulation of ADM was monitored with high performance liquid chromatography.Mdr-1 mRNA,P-glycoprotein（P-gp）,γH2AX expression and γH2AX foci formation were determined by real-time PCR,Western blot and immunocytochemical staining respectively.It was found that different heating methods induced different cytotoxic effects.Water submerged hyperthermia had the strongest cytotoxicity of ADM and Nef combined with hyperthermia had a synergistic cytotoxicity of ADM in the MDR cells.The water submerged hyperthermia increased the cell membrane fluidity.Both water submerged hyperthermia and Nef increased the intracellular accumulation of ADM.The water submerged hyperthermia and Nef down-regulated the expression of mdr-1 mRNA and P-gp.The water submerged hyperthermia could damage DNA and increase the γH2AX expression of SGC7901/ADM cells.The higher temperature was,the worse effect was.Our results show that combined treatment of hyperthermia with Nef can synergistically reverse MDR in human SGC7901/ADM gastric cancer cells.

Use of arrays to investigate the contribution of ATP-binding cassette transporters to drug resistance in cancer chemotherapy and prediction of chemosensitivity

Multidrug 抵抗(MDR ) 是在癌症化疗的一个主要问题。MDR 的最好已知的机制之一是 ATP 有约束力的盒子(ABC ) 的提高的表示运输 ers。当人的 ABC 运输 ers 的一些成员被显示了与提高的表示引起抗药性时，另外的成员的在表示上是否能也在许多模型癌症房间线和诊所贡献抗药性，还没被知道。为介绍 ABCtransporters 的分析的表示的微数组和量的 PCR 数组的最近的开发帮助了处理这些问题。在这篇文章，有在在抗药性和 chemo 敏感预言识别 ABC transporter 基因的 ABC transporter 基因和他们的使用的有限或完整的表的各种各样的数组将被考察。

Expression of multidrug resistance 1 gene and C3435T genetic polymorphism in peripheral blood of patients with intractable epilepsy

BACKGROUND： Increased expression of multidrug resistance 1 （MDR1） mRNA in peripheral blood of patients with intractable epilepsy is not due to epilepsy drugs, but epilepsy behavior. Monitoring MDR1 expression in peripheral blood is a target for MDR1 gene evaluation. OBJECTIVE： To investigate the influence of antiepileptic drugs and seizures on MDR expression in intractable epilepsy, and to analyze the genetic polymorphisms of C3435T in the MDRl gene. DESIGN, TIME AND SETTING： Factorial designs and comparative observations at the experimental center of the Affiliated Hospital of Qingdao Medical College, Qingdao University between October 2003 and October 2004. PARTICIPANTS： A total of 120 subjects were recruited from the epilepsy clinical department of the Affiliated Hospital of Qingdao Medical College. Four groups （n = 30） were classified according to statistical factorial design： intractable epilepsy, treatment response, no treatment, and normal control groups. METHODS： One-step semi-quantitative reverse-transcription polymerase chain reaction technology was used to test expressions of the MDR1 gene in 120 subjects. C3435T polymorphisms in intractable epilepsy group and normal control groups were analyzed by polymerase chain reaction-restriction fragment length polymorphism. MAIN OUTCOME MEASURES： Expression of MDR1 mRNA in the four groups, and C3435T genetic polymorphisms in intractable epilepsy and normal control groups. RESULTS： MDRl gene expression was increased in the intractable epilepsy group, due to the factor seizures, but not the antiepileptic drugs. However, the interaction between the two factors was not statistically significant. Of the 30 subjects in the intractable epilepsy group, the following genotypes were exhibited： 3 （10%） C/C genotype, 9 （30%） C/T genotype, and 18 （60%） T/T genotype at the site of C3435T, while 4 （13%）, 10 （33%）, and 16 （53%） subjects were determined to express these genotypes in the normal control group, respectively. C and T allele frequency were 25% and 75% in the intractable epilepsy group, and 30% and 70% in the normal control group, respectively. However, there was no statistical difference between the groups. CONCLUSION： Results demonstrated that seizures, not antiepileptic drugs, induced MDR1 gene expression in intractable epilepsy. Genetic polymorphisms of C3435T in the MDR1 gene did not contribute to the development of multidrug resistance in patients with intractable epilepsy.

Multi-Drug Resistance Pattern of Lactose Non-Fermenting <i>Escherichia coli</i>as Causative Agent of Urine Tract Infections in Luanda, Angola

This prospective study was carried out to assess the sensitivity and resistance pattern of lactose non-fermenting Escherichia coli from July 2018 to December 2018 in the Laboratory of Microbiology at Luanda Medical Center, Angola. Out of 1170 patient, a total of 120 urine specimens infected with Escherichia coli (>105 CFU/ml) were collected according to the routine protocol of urinalysis. Among these 120 isolates, 25 (21%) isolates were determined as “atypical”, lactose non-fermenting E. colis trains. The twenty-five lactose non-fermenting Escherichia coli strains isolated from urine samples in Luanda Medical Center were declared as Multiple Drugs-Resistant strains with high resistance to Cefalexine (100%), Cefuroxime (100%), Ceftriaxone (92%), Gentamycin (92%), Ciprofloxacin (72%) and Amoxiciclin/Clavulanic (80%). The alarming resistance level to the first-choice drugs for the treatment of urinary tract infections caused by non-fermentative lactose E. coli was observed.

Natural Products Modulate the Multifactorial Multidrug Resistance of Cancer

Multidrug resistance (MDR) is a critical problem in cancer chemotherapy. Cancer cells can develop resistance not only to a single cytotoxic drug, but also to entire classes of structurally and functionally unrelated compounds. Several mechanisms can mediate the development of MDR, including increased drug efflux from the cells by ABC-transporters (ABCT), activation of metabolic enzymes, and defective pathways towards apoptosis. Many plant secondary metabolites (SMs) can potentially increase sensitivity of drug-resistant cancer cells to chemotherapeutical agents. The present thesis investigates the modulation of MDR by certain medicinal plants and their active compounds. The inhibition of ABCTs (P-gp/MDR1, MRP1, BCRP) and metabolic enzymes (GST and CYP3A4), and the induction of apoptosis are useful indicators of the efficacy of a potential medicinal drug. The focus of this study was the possible mechanisms of drug resistance including: expression of resistance proteins, activation of metabolic enzymes, and alteration of the apoptosis and how to overcome their resistance effect on cancer cells. The overall goal of this review was to evaluate how commonly used medicinal plants and their main active secondary metabolites modulate multidrug resistance in cancer cells in order to validate their uses as anticancer drugs, introduce new therapeutic options for resistant cancer, and facilitate the development of their anticancer strategies and/or combination therapies. In conclusion, SMs from medicinal plants exhibit multitarget activity against MDR-related proteins, metabolic enzymes, and apoptotic signaling, this may help to overcome resistance towards chemotherapeutic drugs.

Drug Resistance Pattern in Pulmonary Tuberculosis Patients and Risk Factors Associated with Multi-Drug Resistant Tuberculosis

Introduction: Anti-tuberculosis drug resistance is a major problem in tuberculosis (TB) control programme, particularly multi-drug resistance TB (MDR-TB) in Nepal. Drug resistance is difficult to treat due to its associated cost and side effects. The objective of this study was to assess the drug resistance pattern and assess risk factor associated with MDR-TB among pulmonary tuberculosis patients attending National Tuberculosis Center. Methodology: The comparative cross sectional study was conducted at National Tuberculosis Center during August 2015 to February 2015. Early morning sputum samples were collected from pulmonary tuberculosis suspected patients and subjected to Ziehl-Neelsen staining and fluorochrome staining and culture on Lowenstein-Jensen (LJ) medium. Drug Susceptibility test was performed on culture positive isolates by using proportion method. Univariate and multivariate analysis was computed to assess the risk factors of MDR-TB. Results: Out of 223 sputum samples, 105 were fluorochrome staining positive, 85 were ZN staining positive and 102 were culture positive. Out of 102 culture positive isolates, 37.2% were resistance to any four anti-TB drugs. 11 (28.9%) were initial drug resistance and 28 (43.7%) were acquired drug resistance. The overall prevalence of MDR-TB was 11.7%, of which 2 (5.3%) were initial MDR-TB and 10 (15.6%) were acquired MDR-TB. Univariate and multivariate analysis showed female were significantly associated (P = 0.05) with MDR-TB. Conclusion: Drug resistance TB particularly MDR-TB is high. The most common resistance pattern observed in this study was resistance to both isoniazid and rifampicin. Female were found to be associated with MDR-TB. Thus, early diagnosis of TB and provision of culture and DST are crucial in order to combat the threat of DR-TB.

Detection and clinical significance of multidrug resistance-1 mRNA in bone marrow cells in children with acute lymphoblastic leukemia by real-time fluorescence quantitative RT-PCR

Objective： Multidrug resistance（MDR） is one of the most important reasons for treatment failure and recurrence of acute leukemia. Its manifestations are different in children with acute lymphoblastic leukemia（ALL） which may be due to different detection methods. This study was to detect the expression of MDR1 mRNA in bone marrow cells of children with ALL by real-time fluorescence- quantitative reverse transcription polymerase-chain reaction（FQ-RT-PCR）, and combine minimal residual desease（MRD） detection by flow cytometry（FCM） and to study their relationship with treatment response and prognosis of ALL. Methods：The MDR1 mRNA levels in bone marrow cells from 67 children with ALL[28 had newly diagnosed disease, 27 had achieved complete remission（CR）, 12 recurrent] and 22 children without leukemia were detected by FQ-RT-PCR. MRD was detected by FCM. The patients were observed for 9-101 months, with a median of 64 months. Results：Standard curves of human MDR1 and GAPDH genes were constructed successfully. MDR1 mRNA was detected in all children with a positive rate of 100%. The mRNA level of MDR1 was similar among the newly diagnosed ALL group, CR group, and control group（P 〉 0.05）, but significantly higher in the recurrence group than that in newly diagnosed disease group and control group（0.50 ± 0.55 vs. 0.09 ± 0.26 and 0.12 ± 0.23, P〈 0.05）. 54 ALL patients were followed up, and it was found that MDR1 mRNA level was significantly higher in ALL patients within 3 years duration than that of ALL patients with 3-6 years and over 6 years duration（0.63 ± 0.56 vs. 0.11 ± 0.12 and 0.04 ± 0.06, P〈 0.01）. For the 28 children with newly diagnosed disease, the MDR1 mRNA level was similar between WBC 〉 50 ~ 109 group and WBC〈50 × 10^9 group（P〉 0.05）. In the 33 CR patients, the MDR1 mRNA level was significantly higher in MRD〉10a group than that in MRD〈10a group（0.39 ± 0.47 vs. 0.03 ± 0.03, P 〈 0.05）. Conclusion：The sensitivity and specificity of FQ-RT-PCR in detecting MDR1 mRNA in bone marrowy cells of children with ALL patients are high. MDR1 mRNA is expressed in children with and without leukemia. MDR1 mRNA is highly expressed in the CR ALL patients with high MRD, recurrence and short duration（within 3 years）. Monitoring MRD and the MDR1 mRNA level might be helpful for individual treatment.

Drug resistance pattern of Mycobacterium tuberculosis isolates from patients of five provinces of Iran

Objective:To determine the patterns of resistance to first line anti-tuberculosis(TB)drugs among a collection of Mycobacterium tuberculosis(MTB)isolates from 5 provinces of Iran.Methods:A total of the 6 426 clinical specimens from patients suspected of active TB were collected from March 2010 to June 2012.All specimens were subjected for microscopy and culture tests in the TB centers of studies provinces.Drug susceptibility testing to the first line anti-TB drugs for culture positive MTB was performed on Lwenstein-Jensen(LJ)medium using proportion method.Results:Of 6 426 clinical specimens,261 were culture positive for mycobacteria,of which 252 were MTB and 9 were MOTT(mycobacteria other than tuberculosis).Of 252 MTB isolates.211(83.7%)were pan-susceptible and 41(16.3%)were resistant to at least one drug.Resistance was most common to streptomycin.30 isolates(12.0%),followed by isoniuzid,20isolates(8.0%),rifampin,15 isolates(6.0%)and ethambutol,14 isolates(5.5%).Sixteen(6.3%)MTB isolates were MDR.A clear evidence of heterogeneity amongst the 5 provinces in the proportions with resistance to one or more drugs was observed[χ~2=12.209(4 degrees of freedom),P values=0.015 9].Conclusions:The prevalence of drug resistance in this study area underscoring the need for further enforcement of TB control strategies in the Iran.Drug susceptibility testing for all TB cases to provide optimal treatment,establishing advanced diagnostic facilities for rapid detection of MDR-TB and continuous monitoring of drug resistance are recommended for prevention and control of drug-resistant TB.

Multi Drug Resistance Bacterial Isolates of Surgical Site Infection

Multi drug resistance microorganism is considered to be one of the major health problems. The aim of this study was to determine antibiotic susceptibility pattern of bacterial pathogens of surgical site infection. A total 250 samples were included, out of which 62.4% showed significant bacterial growth. Gram negative bacteria were 85.25% and gram positive bacteria were 14.75%;among them 65.38% of the total isolates were multi drug resistance (MDR). The age group between 31 - 40 found the highest number of isolates 22.4%. Among gram negative bacilli, the highest production of MDR was found in Acinetobacter spp. followed by Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. In gram positive cocci, the highest production of MDR was found in Staphylococcus aureus. Acinetobacter spp. was found highly susceptible to amikacin and gentamycin 20.1% followed by ofloxacin and ciprofloxacin 18.6% and 16.2% respectively. Staphylococcus aureus showed 100% sensitive to clindamycin whereas penicillin showed 100% resistance followed by amoxycillin (93.75%). Amikacine and clindamycin were drugs of choice for gram negative and gram positive bacteria respectively. This study showed that alarming increase of infections was caused by multi drug resistance bacterial organisms. It increases length of stay and may produce lasting sequelae and requires extra resources for investigations, management and nursing care. Surveillance of surgical site infection is a useful tool to demonstrate the magnitude of the problem and find out appropriate preventive methods.