Analysis of mycoplasma pneumoniae nucleic acid testing positive cases of children in Guangzhou / 国际检验医学杂志

Objective To analysis the clinical features of mycoplasma pneumoniae nucleic acid(MP-DNA)testing positive cases of from the region's children,provide the basis for clinical diagnosis and treatment.Methods Outpatient and hospitalized patients with respiratory infection symptoms were sampled pharyngeal swab in the region from 2014 to 2015.After DNA was extracted,polymerase chain reaction method was conducted to detect the MP gene.At the same time,blood routine and mycoplasma pneumoniae antibody were detected from drawing blood.Results There were 209 cases of MP-DNA positive from 2018 cases in children with respiratory tract infection,the positive rate was 10.36 ％.MP-DNA positive rate in 3-＜ 14 years old age group was 18.25 ％,which was higher than other age groups(P＜0.05).The positive rate was 16.11％ from July to September,which was higher than in other month groups(P＜0.05).The positive rate of girl (13.04 ％) was significantly higher than that of boy (8.79 ％) (P＜ 0.05).WBC count was higher than normal for 22.01 ％,normal accounted for 49.28 ％,lower than normal for 28.71％ in MP-DNA positive children.Serum MP-IgG positive rate was 69.86％ in MP-DNA positive children.Conclusion MP-DNA testing has important value to the pediatric respiratory infection diagnosis,detection of multiple projects has important significance to preventing illness aggravating.

Detection of EGFR mutations in pleural effusion of patients with non-small cell lung cancer / 实用医学杂志

Objective To detect the consistency of EGFR mutations in pleural effusion in terminal non-small cell lung cancer(NSCLC)patients by amplification refractory mutation system- polymeric chain reaction (ARMS-PCR).Methods Pleural effusion from 44 cases with advanced NSCLC were collected.DNA was extract-ed from a part of pleural effusion,and EGFR gene18,19,20,and 2 l exons mutations were detected by ARMS-PCR amplification. The left part of pleural effusion was used for the pathological microscopic examination of the embedding and to evaluate the feasibility of pleural effusion direct detection.Part of the case results were compared with tissue or pleural effusion at the same time. Results The mutation rate of EGFR detection in pleural effusion was 54.5%,including 19-del(50.0%)and 21-L858R(50.0%);75.0% of pleural effusion sediment was morpho-logically diagnosed with adenocarcinoma and EGFR mutation rate was 27.3% in pleural effusion with no tumor cell. The consistent rate was 72.7% in 22 cases of pleural effusion and tissue and that was 50.0% in 16 cases of pleural effusion and plasma.The comparison between pleural effusion and organizations and plasma test results was statisti-cally significant(P < 0.05).(P < 0.05).Conclusions EGFR gene mutation rate in pleural effusion is lower than that in tumor tissue specimens in terminal NSCLC patients and tumor tissue is still the best test specimens.

Study of PIK3CA gene mutation status in different clinicopathological characteristics of breast cancer / 国际检验医学杂志

Objective To detect the mutation status of PIK3CA genes in breast cancer and to analyze its relation with clinico‐pathological characteristics .Methods The paraffin tissue samples in 176 cases of breast cancer were selected and the tissue DNA was extracted ,exon9 and exon20 were amplified by ARMS‐PCR .The mutation status of PIK3CA genes were detected ,other tissue samples in 20 cases of mammary gland disease were taken as the negative control .Results Among 176 samples of breast cancer tis‐sues ,45 cases of mutation were found with the mutation rate of 25 .6% ,which was dominated by H1047R mutation rate of exon20 with the mutation rate of 26 .7% (12/45);There were statistical difference between ER (+ ) and ER(-) and between PR(+ ) and PR(-) ,but no statistical difference was found between HER (+ ) and HER(-);PIK3CA gene mutation had correlation with cancer histological grade ,but no obvious correlation with tumor size ,age and lymph node status .Conclusion PIK3CA gene muta‐tion is correlated with breast cancer hormone receptor (HR) expression and tumor progression ;the PIK3CA gene mutation detection has an important significance for guiding the formulation of clinical indiidualized treatment .

Analysis on gene polymorphism of MTHFR C677Tin Han population of south China area / 国际检验医学杂志

Objective To investigate the distribution situation of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism among healthy Han population ,patients with primary hypertension and patients with hypertension complicating coro‐nary heart disease(CHD) in south China area .Methods MTHFR C677T gene polymorphism in 359 cases was detected by adopting the microarray method .The differences of genotypes frequencies were statistically compared between males and females .Results The wild type CC genotypes were common ,accounting for 54 .9% ,the mutation type CT accounted for 33 .1% and TT for 12 .0% . The distribution difference of wild type and mutation type had statistical difference between the male and female populations (P<0 .05);the TT frequency distribution had statistical difference among the patients with hypertension complicating CHD ,healthy population and patients with primary hypertension (P<0 .05) .Conclusion MTHFR C677T gene polymorphism distribution has difference between male and female populations ,and is related to the CHD occurrence in the patients with primary hypertension .

Association of EGFR mutation with histologic subtypes in lung adenocarcinoma / 国际检验医学杂志

Objective To assess the association of epidermal growth factor receptor (EGFR) mutation with histologic subtypes in lung adenocarcinoma .Methods Lung cancer tissues were collected from 3 028 cases of patients with non‐small cell lung cancer , DNA was extracted respectively ,and EGFR gene exons 18 ,19 ,20 and 2l mutations were dectected by ARMS‐PCR amplification . The association of EGFR mutation with histologic subtypes in lung adenocarcinoma was analyzed .Results The mutation rate of EGFR detection was 39 .7% ,most were exon 19 del and exon 21 L858R (proportion 89 .8% );according to the new classification , EGFR gene mutation in infiltrating lesions with micro infiltrating adenocarcinoma and infiltrating adenocarcinoma were different (P<0 .05) .EGFR mutation rates were higher in moderately differentiated lung adenocarcinoma ,degree of differentiation of EGFR mutation rates were statistically different(P<0 .05) .Conclusion The new classification showes a correlation with molecular diag‐nosis ,different subtypes of EGFR mutation rate is different .There is a certain correlation between EGFR gene mutation and the de‐gree of differentiation in adenocarcinoma .

Screening of NDM-1 gene in gram-negative bacilli with decreased sensitivity to carbapenems / 国际检验医学杂志

Objective To determine new delhi metallo-β-lactamase-1 (NDM-1 )gene in strains of gram-negative bacilli with de-creased sensitivity to carbapenems,and to investigate the epidemic situation of strains carrying NDM-1 gene in Guangzhou area. Methods 105 strains of gram-negative bacilli with decreased sensitivity to carbapenems isolated from 201 1 to 2014 were collected. The conserved sequences of NDM-1 gene were screened initially by using polymerase chain reaction(PCR)amplification,and posi-tive strains were confirmed by PCR amplification of the whole sequence.Then NDM-1 gene was cloned into plasmid pUCm-T and sequenced.Results The resistance rates of Enterobacteriaceae bacteria against meropenem,ertapenem and imipenem were 29.09%, 50.91% and 29.09%,respectively.All strains of Acinetobacter baumanii were resistant to meropenem and imipenem.The resist-ance rates of Pseudomonas aeruginosa against meropenem and imipenem both were 88.46%.4 strains were NDM-1 gene positive, including 1 strain of Klebsiella pneumoniae,2 strains of Escherichia coli,1 strain of Enterobacter cloacae.Successful establishment of cloning plasmid pUCm-T-NDM-1 was confirmed by using double enzyme digestion and sequencing.The sequencing results were compared with BLAST,it was showed that the sequences were exactly the same in four cloned plasmids,and sequences of NDM-1 were also exactly the same with those in domestic and foreign.Conclusion Strains of NDM-1 producing gram-negative bacilli exist in Guangzhou area,and whole sequence of NDM-1 gene carried in these strains are exactly the same with those found in foreign.

Study on the molecular mechanism of the dissemination of a novel CTX-M-like extended spectrum beta-lactamase-producing Escherichia coil / 中国医师杂志

Objective To investigate the distribution of the CTX-M- extended spectrum beta-lactamase (ESBLs) producing Esche- richia coli(ECO) and the molecular mechanism of dissemination. Methods To analyze the drug resistance of the 43 isolates, Kirby-Bauer susceptibility method was used. Multiple polymeraso chain reaction (PCR) was used to amplify the gene of ESBLs, AmpC, full length of blaCTX-M-like gene, insertion sequence (IS) ISEcp1B, IS903 , IS26 and integron I. NEST-PCR was used to detect if the beta-lactamase gene lo- cated in the integron I. The product of full length of bla-CTX-M like gone amplified by PCR was sequenced. Results Susceptibility test showed the resistance from high to low in turn was Ampicillin (97.68%), Coftriaxone (67.44 % ), piperacillin(65.12 % ), Cefotaxime (62.79 % ) ,Coftasidime(58.14% ), Cofasolin(55.81% ), Cofepime (53.49%), Cefexitin(51.16%), ciprofloxacin (44. 19% ), Aztreo- nam(41.86% ), Cefoperasone/Sulbactam ( 20.93% ), Amikacin (0% ), Imipenem (0% ), respectively. ECO was susceptive to Imipenem. CTX-M-G1 was found in 25 strains of ECO , TEM, SHV, CTX-M-G1, ISEcp1B, and integron I were found in the nine isolates. IS903 were found in ECO 3 and 5, and IS26 was found in ECO 3. In ECO 3 and 5, blaCTX-M-like was flanked upstream by ISEcp1B element that provided -35 and -10 promoter sequences and a right inverted repeat (IRR) recognized by transposase, downstream by IS903 provided an inverted re- peat, ISEcp1 B and IS903 composed the complex transpeson. Conclusion ISEcplB may drive the expression and dissemination of blaCTX-M-like gene at a high level.

Screening of ?-Lactamase in Multi-resistant Gram-negative Bacilli and Analysis of Characteristics of Susceptibility of Phenotype and Genotype / 中华医院感染学杂志

OBJECTIVE To investigate the phenotypical and genotypical characteristics of the ?-lactamase in the 302 strains of Gram-negative bacilli,and assess the characteristics of the drug resistance.METHODS The phenotypes of ?-lactamase were detected in the Gram-negative bacilli by disc diffusion screen test,which were further ascertained by disc diffusion confirmatory test,a cefoxitin three dimensional test,and metallo ?-lactamases double-disc synergy test.The ?-lactamases were detected by multiple PCR amplification,then DNA product was sequenced.Antibiotics susceptibility was detected by K-B method.RESULTS Among the clinical Gram-negative isolates,a total of 26.49%(80/302)strains′ ?-lactamases phenotypes were positive,ESBLs,ESBLs combined with AmpC enzyme,ESBLs combined with AmpC enzyme and MBL,and AmpC enzyme producing strains were found in 16.56%,6.62%,1.66% and 0.66%,respectively.A total of 24.83% strains′?-lactamases phenotypes were positive,strains produced ESBLs,ESBLs combined with AmpC enzyme,ESBLs combined with AmpC enzyme and MBL,and AmpC enzyme producing strains were found in 17.55%,6.95%,0.33%,and 0.33%,respectively.Drug-sensitivity test showed multi-resistant Gram-negative isolates were more sensitive to amikacin(18.75%),and heavier resistant to ampicillin(97.50%).CONCLUSIONS ?-Lactamase producing Gram-negative bacilli are resistant to multi-antibiotics.

The appearance of a novel CMY type class C cephalosporinase (AmpC) in southern China / 中国医师杂志

Objective To investigate the antibiotic resistance and molecular epidemiology character of ?-lactamase producers among clinical isolates of Citrobacter freundii.Methods Four strains of Citrobacter freundii were detected by K-B susceptibility method and three-dimensional test.The ?-lactamase gene was identified by polymerase chain reaction(PCR) and sequencing.Results The No.29 strain of Citrobacter friundii was multiple-drug-resistant and proved to produce CMY,DHA type AmpC,TEM and SHV type of extended-spectrum ?-lactamases(ESBLs).The sequencing of corresponding DNA revealed 97% identities of the CMY-2 amino acid sequence.It was a new type of cephalosporinase.Conclusion A novel strain of Citrobacter friundii with CMY type AmpC,DHA type AmpC,TEM and SHV type ESBLs has been found in southern China and it is multiple-drug-resistant.