Association between the polymorphisms of the VDR gene and kidney stone formation in Guangxi population

Objective:To investigate the relationship between the rs9729,rs11574129,BsmI(rs1544410),TaqI(rs731236)and DdeI(rs3782905)polymorphisms of the vitamin D receptor(VDR)gene and kidney stone formation in a study group from Guangxi.Methods:A hospital-based casecontrol study including 890patients with kidney stone formation and 822age-and sex-matched controls without stone formation was conducted.Five single-nucleotide polymorphisms(SNPs)of the VDR gene were studied using SNPscanTMhighthroughput SNP classification assays.Results:The T allele variant of rs9729significantly increased the risk of kidney stone formation(P=0.021).In particular,a significantly increased risk of kidney stone formation was found in the combined genotypes TG/TT of rs9729compared with the wild GG genotype after covariate adjustment.However,after gender stratification analysis,compared with the wild GG genotype,the GT,TT and GT/TT genotypes of rs9729increased the risk of kidney stone formation in males.Moreover,the GA and GA/GG genotypes of rs11574129 were associated with increased risk of kidney stone formation in males.By contrast,the GC and GC/CC genotypes of DdeI(rs3782905)significantly decreased the risk of kidney stone formation in males.Haplotype analysis suggested that the five-locus polymorphism of VDR was significantly related to kidney stone formation in male participants(P=0.0025).Conclusion:TheT allele variant of the rs9729polymorphism of the VDR gene was significantly related to the risk of kidney stone formation.Gender may affect the association between the rs9729,rs11574129and DdeI polymorphisms of the VDR gene and the risk of kidney stone formation in the Chinese population.

Detection of the polymorphism at codon 72 in exon 4 of p53 gene by PCR－SSCP

By employing different gel components and electrophoresis conditions, the PCR-SSCP(polymerase chain reaction-single-stranded conformation polymorphism) method was used to detect the polymorphism(CCC or CGC ) of codon 72 in exon 4 of p53 gene. The results

Application of PCR-SSCP in detecting rpoB drug resistant gene polymorphism of M. tuberculosis L-form from pneumoconiosis patients with tuberculosis

Objective: To study the relationship between the polymorphism of drug resistant gene rpoB and drug resistance against rifampicin(RFP) of M. tuberculosis L-forms, and to evaluate its clinical application. Methods: A total of 52 clinical isolated strains of M. tuberculosis L-forms were collected. rpoB gene polymorphism was analyzed by polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) and conventional antimicrobial susceptibility test (AST). Their results were compared. Results: AST results showed that 38 of 52 clinical isolated strains were drug resistance (73.08％),while PCR-SSCP indicated 65.38％ (32/52) rpoB gene polymorphism. There was no statistic significance(χ2= 2.4914) between the 2 methods. Conclusion:Combined the application of PCR-SSCP with AST in detecting rpoB drug resistant gene polymorphism of M. tuberculosis L-form from pneumoconiosis patients with tuberculosis may have advantages at earlier diagnosis and guidance of clinical medications.

Microbial community structure in different wastewater treatment processes characterized by single-strand conformation polymorphism (SSCP) technique

In order to investigate microbial community structures in different wastewater treatment processes and understand the relationship between the structures and the status of processes,the microbial community diversity,variety and distribution in five wastewater treatment pro cesses were studied by a culture-independent genetic fingerprinting technique single-strand conformation poly-morphism(SSCP).The five processes included denitrifying and phosphate-removal system(diminished N),Chinese traditional medicine wastewater treatment system(P),beer wastewater treatment system(W),fermentative biohydrogen-producing system(H),and sulfate-reduction system(S).The results indicated that the microbial community profiles in the wastewater bioreactors with the uniform status were very similar.The diversity of microbial populations was correlated with the complexity of organic contaminants in wastewater.Chinese traditional medicine wastewater contained more complex organic components;hence,the population diversity was higher than that of simple nutrient bioreactors fed with molasses wastewater.Compared with the strain bands in a simulated community,the relative proportion of some functional microbial populations in bioreactors was not dom-inant.Fermentative biohydrogen producer Ethanoligenens harbinense in the better condition bioreactor had only a 5% band density,and the Desulfovibrio sp.in the sulfate-reducing bioreactor had less than 1.5%band density.The SSCP profiles could identify the difference in microbial community structures in wastewater treatment processes,monitor some of the functional microbes in these processes,and consequently provide useful guidance for improving their efficiency.

Single strand conformation polymorphism for analysis of genomic variability of hepatitis C virus nonstructure 5A region

Abstract Objective To establish a convenient method to detect the genomic population with hepatitis C virus (HCV) at nonstructure 5A (NS5A) region and to determine the correlation between the genomic population complexity at NS5A region and disease stage. Methods The sera from 52 patients with chronic hepatitis C virus infections were analysed using single strand conformation polymorphism (SSCP). In the SSCP, an asymmetric polymerase chain reaction (PCR) was carried out on the 455 bp products of the first round PCR at the NS5A region and the number of band of single strand deoxyribonucleic acid (DNA) which reacted with complemental DNA probe specific for the NS5A region after gel electrophoresis was analyzed. Results In 90% patients with chronic persistent hepatitis, the bands of single strand DNA was limited to one, and in those with chronic active hepatitis or liver cirrhosis, two or more bands of DNA were frequently detected. In about half of patients with hepatocellularcarcinoma, three or more bands were found. The number of bands increased with the progression of liver disease. The multivariate analysis showed that the progression of liver disease was the independent factor of viral diversity (P<0.025) and was not related to the age, sex, the route of infection and the titer of hepatitis C virus ribonucleic acid (HCV RNA). Conclusion These results suggest that the genomic variability of HCV at NS5A region increases with the progression of liver disease, and this may be closely related to the clinical features of type C liver disease.

Cloning and polymorphism analysis of IL-4 proximal promoter in asthmatic children

OBJECTIVE: To clone and study the polymorphism within interleukin-4 (IL-4) proximal promoter of asthmatic children. METHODS: The IL-4 proximal promoter segments were amplified and selected by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) with genomic DNA from ten healthy children and forty patients with dominantly allergic familial histories as templates. The selected PCR segments were cloned into recombinant plasmids pIL-4-Jx2. The PCR inserts were sequenced by dideoxy chain termination method. RESULTS: Seven aberrant bands were found in SSCP analysis from forty asthmatic patients. The sequencing results showed that four variant sites were found within or adjacent to the known IL-4 regulatory element. A C to A transversion located at -229 position was just within the positive regulatory element-I (PRE-I) in one patient. A C to T transition adjacent to the negative regulatory element-II (NRE-II) and an extra G adjacent to TATA box were found in two patients. A five base nucleotide deletion was found near signal transducers and activators of transcription-6 responsive element (STAT-6 RE) in one patient. CONCLUSION: There were polymorphisms within the IL-4 proximal promoter of allergic asthmatic patients and these polymorphisms might result in aberrant expression of IL-4 gene and asthma.

Polymorphisms and functions of the aldose reductase gene 5' regulatory region in Chinese patients with type 2 diabetes mellitus

OBJECTIVE: To screen the 5' regulatory region of the aldose reductase (AR) gene for genetic variabilities causing changes in protein expression and affecting the promoter function. METHODS: The screenings were carried out by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). All SSCP variants were submitted for DNA sequencing and inserted into the plasmid chloromycetin acetyl transferase (CAT) enhancer vector. The constructs were used to transfect Hela cells, and CAT assays were performed to assess promoter activity. Gel mobility shift and footprinting assays were also performed to determine the interaction between the DNA and nuclear proteins. RESULTS: Two polymorphisms, C (-106) T and C (-12) G, were identified in the regulatory region in 123 Chinese control subjects and 145 patients with type 2 diabetes mellitus. The frequencies of genotypes WT/WT, WT/C (-12) G and WT/C (-106) T were not significantly different between the subjects and patients. In the patients with and without retinopathy, frequencies of WT/C (-106) T were 31.5% and 17.5% (P 0.05) respectively. The total frequency of WT/C (-12) G and WT/C (-106) T in patients with retinopathy was 41.8%, significantly higher than that (20.0%) in patients without retinopathy (P

QUANTITATIVE ANALYSIS OF C BAND POLYMORPHISM ON CHROMOSOMES 1,9, 16, AND Y IN HAN NATIONALITYPOPULATION OF CHINA

Polymorphism of human chromosomal constitutive heterochromatin (C band) has been found to have a hereditary character in populations. A large number of informations have proved that the difference of C band polymorphism exists between various nationalities and populations. China is a country of many nationalities, so

Study on mitochondrial DNA diversity among 7 inbred strains of mice

Objective：To study the genetic variation of mitochondrial DNA （mtDNA） among common laboratory strains of inbred mice. Methods： The genetic polymorphism of mtDNA among 4 classical laboratory strains of inbred mice and 3 inbred strains of mice established in China was analyzed by polymerase chain reaction coupled with restriction fragment length polymorphism（PCR-RFLP） and PCR coupled with single-stranded conformation polymorphism（PCR-SSCP）. Results： With regard to the D-loop （Displacement loop, D-loop）, tRNA^ Met＋Glu＋Ile, and ND3 （NADH dehydrogenase subunit 3, ND3） gene fragments of mtDNA from these mice,no variation was revealed by PCR-RFLP at 46 restriction enzyme sites. Further analyzed by PCR-SSCP,the D-loop 5＇fragment and 3＇end fragment of mtDNA from these mice also showed no genetic variation. Conclusion： Owing to maternal mode of inheritance of mtDNA,the results indicate that these common inbred strains of mice share the same maternal lineage.

The point mutation of p53 gene exon7 in hepatocellular carcinoma from Anhui Province,a non HCC prevalent area in China

AIM: In hepatocellular carcinoma (HCC) prevalent areas of China, the point mutation of p53 exon7 is highly correlated with Hepatitis B virus(HBV) infection and aflatoxin B intake. While in non-HCC-prevalent areas of China, these factors are not so important in the etiology of HCC. Therefore, the point mutation of p53 exon7 may also be different than that in HCC-prevalent areas of China. The aim of this study is to investigate the status and carcinogenic role of the point mutation of p53 gene exon7 in hepatocellular carcinoma from Anhui Province, a non-HCC-prevalent area in China. METHODS: PCR PCR-SSCP and PCR-RFLP were applied to analyze the homozygous deletion and point mutation of p53 exon7 in HCC samples from Anhui, which were confirmed by DNA sequencing and Genbank comparison. RESULTS: In the 38 samples of hepatocellular carcinoma, no homozygous deletion of p53 exon7 was detected and point mutations of p53 exon7 were found in 4 cases, which were found to be heterozygous mutation of codon 249 with a mutation rate of 10.53%(4/38). The third base mutation(G-T) of p53 codon 249 was found by DNA sequencing and Genbank comparison. CONCLUSION: The incidence of point mutation of p53 codon 249 is lower in hepatocellular carcinoma and the heterozygous mutation of p53 exon7 found in these patients only indicate that they have genetic susceptibility to HCC. p53 codon 249 is a hotspot of p53 exon7 point mutation, suggesting that the point mutation of p53 exon 7 may not play a major role in the carcinogenesis of HCC in Anhui Province, a non-HCC-prevalent area in China.

珍珠的成分、微结构及成因研究

综述了现有珍珠中无机成分、有机质、微量元素、珍珠层仿生学等相关研究领域的进展,重点探讨了结晶多型与无机相转变、有机质作用、微环境影响等问题。珍珠微结构成因理论包括"隔室"说、矿物桥说、模板说、多模板成因说等,在研究珍珠层形成机制时应综合考虑微环境、有机质及无机成分在无机晶体成核、结晶、长大各个阶段所起的作用。

结核分枝杆菌katG和inhA基因突变的研究

为了解结核分枝杆菌耐异烟肼（ＩＮＨ）分离株ｋａｔＧ基因和ｉｎｈＡ调节序列的突变情况，探讨其在ＩＮＨ耐药性中的可能作用。应用聚合酶链反应（ＰＣＲ）和ＰＣＲ－单链构象多态性（ＳＳＣＰ）方法对６２株结核分枝杆菌临床分离株的ｋａｔＧ基因和ｉｎｈＡ调节序列进行分析。ＰＣＲ分析结果显示：ｋａｔＧ基因和ｉｎｈＡ调节序列的敏感性为１～１０ｐｇＤＮＡ；其引物ＰＣＲ扩增都具有较高的特异性。以Ｈ３７Ｒｖ标准株为对照，１３株敏感株中，１２株ｋａｔＧ基因扩增产物ＳＳＣＰ泳动正常，１株ｋａｔＧ异常；２４株耐非ＩＮＨ抗结核药物株中，８株ｋａｔＧＳＳＣＰ异常；上述２７株的ｉｎｈＡ调节序列ＳＳＣＰ均泳动正常。２５株耐ＩＮＨ株中，３株ｋａｔＧ基因ＰＣＲ扩增阴性，２２株ｋａｔＧ扩增阳性，其中１６株ＳＳＣＰ泳动异常；４株ｉｎｈＡ调节序列ＳＳＣＰ泳动异常，其ｋａｔＧ基因ＳＳＣＰ也异常。结果表明，某些结核分枝杆菌ＩＮＨ耐药性可能是由于其ｋａｔＧ基因完全缺失、ｋａｔＧ基因或ｉｎｈＡ调节序列突变所致，但某些菌株也可能与其无关，是其它耐药基因所致或存在多种机制，尚需进一步探讨。

无脊椎动物免疫分子的多态性

一般认为,非特异性免疫分子由于胚系基因种类有限而不具备多态性.但近年来人们发现,脊椎动物γ/δT细胞受体、B1细胞受体、某些固有免疫成分,以及无脊椎动物的某些免疫球蛋白超家族(immunoglobulin superfamily,IgSF)分子、抗菌肽和模式识别受体(pattern recognition receptors,PRR)等同样具有较高程度的多态性.与特异性免疫分子相似,其多态性形成机制主要为基因组水平的基因重排、单核苷酸多态性、DNA突变和mRNA水平的外显子可变剪接.该多态性的出现可能是无脊椎动物的一种适应性进化,其应为低等生物特异性识别和防御不同病原微生物感染的分子基础.本文就无脊椎动物免疫分子多态性的最新研究进展及其可能的形成机制与意义进行概述.

Comprehensive screening for reg1α gene rules out association with tropical calcific pancreatitis

AIM: To investigate the allelic and haplotypic association of reg1α gene with tropical calcific pancreatitis (TCP). Since TCP is known to have a variable genetic basis, we investigated the interaction between mutations in the susceptibility genes, SPINK1 and CTSB with reg1α polymorphisms. METHODS: We analyzed the polymorphisms in the reg1α gene by sequencing the gene including its promoter region in 195 TCP patients and 150 ethnically matched controls, compared their allele and haplotype frequencies, and their association with the pathogenesis and pancreaticolithiasis in TCP and fibro-calculous pancreatic diabetes. RESULTS: We found 8 reported and 2 novel polymo-rphisms including an insertion-deletion polymorphism in the promoter region of reg1α. None of the 5' UTR variants altered any known transcription factor binding sites, neither did any show a statistically significant association with TCP. No association with any reg1α variants was observed on dichotomization of patients based on their N34S SPINK1 or L26V CTSB status. CONCLUSION: Polymorphisms in reg1α gene, including the regulatory variants singly or in combination with the known mutations in SPINK1 and/or CTSB genes, are not associated with tropical calcific pancreatitis.

Virulence and potential pathogenicity of coccoid Helicobacter pylori induced by antibiotics

AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole. Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot. The mutation of the genes including ureA, ureB,hpaA, vacA and cagA, related with virulence, was detected by means of PCR and PCR-SSCP. RESULTS: In the coccoid H. pylori,the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells all decreased. In strain F44, the rate and index of adherence reduced from 70.0% +/- 5.3% to 33% +/- 5.1% and from 2.6 +/- 0.4 to 0.96 +/- 0.3 (P 【 0.01), respectively. The invasion of coccoid H. pylori into Hep-2 cell could be seen under electronmicroscope. SDS-PAGE showed that the content of the protein with the molecular weight over Mr 74000 decreased, and the hybriditional signal in band M(r) 125000 weakened, while the band M(r)110000 and M(r)63000 strengthened in coccoid H.pylori as shown in Western blot. The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA. CONCLUSION: The virulence and the proteins with molecular weight over M(r)74000 in coccoid H.pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA, vacA and cagA genes, suggesting that coccoid H.pylori may have potential pathogenicity.

The Sequence Variations of Intron-3 of the α-Amylase Gene in Adzuki Bean

This study describes variation of intron-3 of α-amylase gene from 156 breeds of adzuki beans using SSCP(single-strand conformation polymorphism)analysis. Based on α-amylase gene structure and sequence, A pair of PCR primers, F (CCTACATTCTAACACACCCT) and R (GCATATTGTGCCAGTACAAT) were designed to amplify intron-3 fragments of α-amylase gene. 14 variant types were detected, including 13, 9, 10, 4 variant types in the wild, weed, locally cultivated and modern brought-up adzuki beans respectively, 9, 8, 7 variant types of the wild adzuki beans from Japan, China and Korea respectively, and some other variant types in the local adzuki beans from China and Bhutan. 60% of subjects of cultivated races were found to be EE type in the experiment. In addition, sequence analysis of intron-3 of α-amylase gene from 8 variant types reveals the evolution process of various variant types in adzuki beans.

砂梨果皮转录组SNP位点发掘及其功能注释分析

从褐色砂梨品种‘黄花’(Pyrus pyrifolia Nakai‘Huanghua’)色泽形成期的果皮转录组数据开发SNP分子标记。检测了75764条unigene(总长度55676271bp)序列信息后,在25589条unigene(33.77%)中共发现SNP位点162048个,SNP发生频率为1/344bp,其中转换(transition)102342个,颠换(transversion)59706个。在所有变异类型中,A/G和C/T发生频率最高,分别达31.66%和31.50%。为进一步对得到的SNP所在基因功能进行分析,将包含SNP位点的25589条unigene序列注释到GenBank Nr蛋白数据库、Nt核苷酸数据库和Swiss-prot数据库中,并对其进行GO分类、COG分类注释和代谢通路注释(KEGG pathway),结合已有研究,筛选到1178个可能与果皮色泽形成相关的SNP标记。

Influence of quasispecies on virological responses and disease severity in patients with chronic hepatitis C

AIM:To elucidate the influence of quasispecies on virological response and disease severity in patients with chronic hepatitis C. METHODS:Forty seven patients with hepatitis C [32 with chronic active hepatitis (CAH), 9 with cirrhosis, and 6 with hepatocellular carcinoma (HCC)] were screened for the presence of quasispecies by single stranded conformational polymorphism (SSCP) analysis in the hypervariable region (HVR) and non-structural 5B (NS5B) viral genes of hepatitis C virus. The 41 patients excluding those with HCC were on therapy and followed up for a year with the determination of virological response and disease severity. Virus isolated from twenty three randomly selected patients (11 non-responders and 12 showing a sustained virological response) was sequenced for the assessment of mutations. RESULTS:The occurrence of quasispecies was proportionately higher in patients with HCC and cirrhosis than in those with CAH, revealing a significant correlation between the molecular evolution of quasispecies and the severity of disease in patients with hepatitis C. The occurrence of complex quasispecies has a significant association (P < 0.05) with the non-responders, and leads to persistence of infection. Significant differences (P < 0.05) in viral load (log10 IU/mL) were observed among patients infected with complex quasispecies (CQS), those infected with simple quasispecies (SQS) and those with no quasispecies (NQS), after 12 wk (CQS-5.2 ± 2.3, SQS-3.2 ± 1.9, NQS-2.8 ± 2.4) and 24 wk (CQS-3.9 ± 2.2, SQS-3.0 ± 2.2, NQS-2.1 ± 2.3) in the HVR region. However, a statistically significant difference (P < 0.05) was observed between the viral loads of patients infected with CQS and those infected with NQS in NS5B viral gene after 24 wk (CQS-3.9 ± 2.2, SQS-3.0 ± 2.2, and NQS-2.1 ± 2.3) and 48 wk (CQS-3.1 ± 2.7, SQS-2.3 ± 2.4, NQS-2.0 ± 2.3) of therapy. Disease severity was significantly associated with viral load during therapy. The strains isolated from non-responders showed close pairing on phylogeny based on the NS5B gene, but dissimilar HVR regions. This revealed the possibility of the selection of resistant strains during the evolution of quasispecies in NS5B. CONCLUSION:Viral quasispecies may be an important predictor of virological responses to combination therapy in patients with chronic hepatitis C. Complex quasispecies and resistant strains may lead to high viral loads during therapy, with a concerted effect on disease severity.

骨肉瘤p21^(WAF1/CIP1)基因DNA序列分析及其mRNA、p21蛋白表达

【目的】通过检测骨肉瘤组织中p21WAF1/CIP1基因的表达及其DNA序列变化,探讨它们与骨肉瘤生物学特性之间的关系及其对预后的评价。【方法】采用原位杂交及免疫组化法检测45例人骨肉瘤p21WAF1/CIP1基因mRNA及p21蛋白的表达。采用PCR-SSCP方法检测骨肉瘤p21WAF1/CIP1基因DNA变化。采用双脱氧核苷酸末端终止法进行DNA的直接测序。【结果】①p21蛋白表达阳性率在骨肉瘤中为18%(8/45);②p21WAF1/CIP1基因mRNA表达阳性率在骨肉瘤中为42%(19/45);③DNA序列分析结果显示,骨肉瘤中p21WAF1/CIP1基因第三外显子(exon3)的cDNA全长序列的609位碱基处发生C→T改变,发生率为47%(17/36)。exon2a的cDNA全长序列的187位、303位碱基处发生G→T改变,发生率为6%(2/36)。exon2b的cDNA全长序列的522位碱基处发生G→A改变,发生率为2.7%(1/36)。【结论】①随着骨肿瘤恶性度的升高,p21WAF1/CIP1基因mRNA及p21蛋白的表达下降。②p21WAF1/CIP1基因mRNA在骨肉瘤中的表达对预后有影响。③本实验对中国人群骨肉瘤p21WAF1/CIP1基因DNA多态性位点进行了新的定位,这些位点可能会对今后对该基因的研究提供有意义的参考。

Detecting drug resistant genetic mutation among pneumoconiosis patients complicated with tuberculosis in Mycobacterium tuberculosis L-forms application of PCR-SSCP technique in Huainan mining district

Objective： To study the relationship between drug resistant genetic mutation and drug resistance in Mycobacterium tuberculosis L-form, discuss the internal relationship between drug resistances and drug-resistant related genes and explore the value of PCR- SSCP to clinical application. Methods： A total of 52 clinically isolated strains of tuberculosis L-form were collected among 97 pneumoconiosis patients complicated with tuberculosis. The gene mutations of katG, rpoB and rpsL were detected by PCR-SSCP, and the results were compared with those analyzed by traditional antimicrobial susceptibility test（AST）. Results： The gene muta- tion rates of katG, rpoB and rpsL by PCR-SSCP were respectively 57.70% （30/52）, 65.38% （32/52） and 40.38% （21/52）. The rate of reversion was 78.85%（41/52） and the result of drag-resistant genes was invariable. The results of AST showed that there were 40 （76.92%） multi-drug resistant strains in 52 clinically isolated strains. The number for three-drug resistant strain was 21 （40.38%） and that of two-drug resistant was 19（36.54%）, but only 12（23.08%） strains were one drug resistant. The rate of total drug-resistance was 100%, but there were 15 strains of allied mutation of three genes, 16 of two mutations and 6 of only one by PCR-SSCP. The coincidences were respectively 71.43%, 84.12% and 50.00%. Then there was no significant difference between the allied mutations of multi-drug resistant gene and the mutations of only one drug resistant gene （P 〉 0.05）. Conclusion： PCR-SSCP technique has a higher sensibility and specificity to detect the genes of katG, rpoB and rpsL in tuberculosis L-form among pneumoconiosis complicated with tuberculosis,and the detecting rate of two drug resistant strains and three drug resistant strains was higher. The combined application of PCR-SSCP and AST has advantages at earlier diagnosis and guidance of clinical medications.