Correlation between TEM1 expression and efficacy of neoadjuvant chemotherapy in patients with gastric cancer / 中国肿瘤临床

Objective: To detect the expression of P53, human epidermal growth factor receptor-2 (HER-2), and tumor endothelial marker 1 (TEM1) in gastric cancer tissues, analyze their correlation with clinical efficacy, and explore their potential roles as biomarkers for neoadjuvant chemotherapy. Methods: Sixty-three patients with gastric cancer who underwent fluorouracil-based neoadjuvant che-motherapy in The First Hospital of Lanzhou University from May 2015 to May 2017 were enrolled. Using immunohistochemistry, the expression of P53, Her2, and TEM1 was detected in 63 gastric cancer specimens before neoadjuvant chemotherapy. The efficacy of neoadjuvant chemotherapy was assessed by imaging. The relationship between the expression of P53, HER-2, and TEM1 and the effi-cacy of neoadjuvant chemotherapy was analyzed. Results: The total effective rate of neoadjuvant chemotherapy in 63 patients with advanced gastric cancer was 69.8%, with 2, 7, and 35 patients achieving complete remission, partial remission, and stable disease, re-spectively. Disease progression was noted in 19 patients. Univariate analysis revealed that patients positive for TEM1 and having high T stage had a poor response to neoadjuvant chemotherapy (P<0.05); furthermore, location, differentiation, and size of tumor; P53 posi-tivity (P=0.488); and Her-2 positivity (P=0.106) were not associated with the efficacy of neoadjuvant chemotherapy for gastric cancer. Multivariate analysis revealed that TEM1 positivity and a higher T stage could be factors that predicted the response to neoadjuvant chemotherapy in patients with advanced gastric cancer. Conclusions: TEM1, as a marker of tumor stroma, may be an important molec-ular biological indicator that predicts the poor response to neoadjuvant chemotherapy in patients with gastric cancer.

Study on the drug resistance of clinical strain of acinetobacter baumannii mediated by TEM-1 beta-lactamases and porin CarO / 天津医药

Objective To investigate the mechanism of drug resistance of sulbactam mediated by TEM-1 beta-lactamases and porin CarO in clinical strains of acinetobacter baumannii. Methods Twenty-four unrepeated clinical acinetobacter baumannii strains were divided into sensitive strain group (n=6) and insensitive strain group (n=18) by susceptibility testing to sulbactam.Antibiotics susceptibility test was carried out using the Kirby-Bauer method.BlaTEM-1and carO genes were amplified by PCR.Four blaTEM-1positive strains(A3,A5,1327 and C1)were selected,and their amplified products were sequenced.The quantitative real-time RT-PCR was used to analyze mRNA transcriptional levels of blaTEM-1 and carO genes. Results Resistant rates of the sensitive strain group for meropenem, imipenem, cefoperazone, ciprofloxacin,gentamicin and ampicillin were 1/6,2/6,3/6,1/6,5/6 and 5/6,and resistant rates of the insensitive strain group were 6/18,10/18,18/18,18/18 and 18/18.BlaTEM-1genes were amplified in 16 insensitive strains,and blaTEM-1was negative in sensitive strains. The carO genes were amplified in all 24 strains.There was no significative mutation in the 4 strains of blaTEM-1genes. The promoters of the strains A3, A5 and 1327 were P4, and C1 was P3. There was a positive correlation between the mRNA expression of blaTEM-1and the MIC value of sulbactam (rs=0.551, P=0.027). There was no difference in the mRNA expression of carO between the two groups.Conclusion The clinical strains are seriously resistant to antibiotics.The main resistance mechanism of clinical strains to sulbactam is the high mRNA expression of blaTEM-1,and the promoter may be one of the reasons of high expression of TEM-1.

ß-lactamases produced by amoxicillin-clavulanate-resistant enterobacteria isolated in Buenos Aires, Argentina: A new blaTEMgene / ß-lactamasas producidas por enterobacterias resistentes a amoxicilina-ácido clavulánico aisladas en Buenos Aires, Argentina: un nuevo gen blaTEM

La resistencia a la combinación de ß-lactámico/inhibidor de ß-lactamasa en enterobacterias es un problema creciente que no ha sido estudiado intensamente en Argentina. En el presente trabajo, 54/843 enterobacterias recolectadas en un hospital universitario de la ciudad de Buenos Aires fueron resistentes a ampicilina-sulbactama, pero se mantuvieron sensibles a las cefalosporinas de segunda y tercera generación. Se analizaron los mecanismos enzimáticos presentes en los aislamientos que también fueron resistentes a amoxicilina-ácido clavulánico (AMC) (18/54). La secuenciación reveló dos variantes diferentes de blaTEM-1, donde blaTEM-1b es el alelo más frecuentemente detectado (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis y 1 Raoultella terrigena), seguidos por blaTEM-1a(1 K. pneumoniae). La resistencia a AMC parece estar asociada principalmente con la hiperproducción de TEM-1 (sobre todo en E. coli) o con la coexpresión con ß-lactamasas tipo OXA-2 y/o SHV (K. pneumoniae y P. mirabilis). Se describió una nueva variante de blaTEM(TEM-163) en un aislamiento de E. coli que presentó una CIM frente a AMC de 16/8 µg/ml. La enzima TEM-163 contiene dos sustituciones de aminoácidos respecto de TEM-1, Arg275Gln y His289Leu. Teniendo en cuenta la alta actividad específica observada y la baja IC50 para el ácido clavulánico, el patrón de resistencia de este aislamiento parece obedecer a la hiperproducción de la nueva variante de la ß-lactamasa de amplio espectro, en lugar de vincularse con un comportamiento similar al de una TEM resistente a inhibidores (IRT).

Resistance to ß-lactam/ß-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second-and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed. Sequencing revealed two different variants of blaTEM-1, being blaTEM-1b the most frequently detected allelle (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis and 1 Raoultella terrigena) followed by blaTEM-1a(1 K. pneumoniae). Amoxicillin-clavulanate resistance seems to be mainly associated with TEM-1 overproduction (mostly in E. coli) or co-expressed with OXA-2-like and/or SHV ß-lactamases (K. pneumoniae and P. mirabilis). A new blaTEMvariant (TEM-163) was described in an E. coli strain having an AMC MIC value of 16/8 µg/ml. TEM-163 contains Arg275Gln and His289Leu amino acid substitutions. On the basis of the high specific activity and low IC50 for clavulanic acid observed, the resistance pattern seems to be due to overproduction of the new variant of broad spectrumß-lactamase rather than to an inhibitor-resistant TEM (IRT)-like behavior.

Genotype analysis of ESBLs-producing Klebsiella pneumoniae isolates / 中国感染与化疗杂志

Objective To identify the genotypes of ESBLs-producing Klebsiella pneumoniae isolates from the First Affiliated Hospital,Shantou University Medical College.Methods The MICs of 10 antibiotics were determined by agar-dilution against the clinical isolates of ESBLs-producing K.pneumoniae.PCR were performed with specific primers for blaTEM,blaSHV, blaCTX-M and blaOXA respectively.PCR products were cloned and sequenced.Results The results of PCR showed that a- mong the 83 strains of ESBLs-producing K.pneumoniae,75 were positive for blaTEM,41 positive for blaSHV,25 poitive for blaCTX-M,9 positive for hlaOXA.Three genotypes were found in 13 strains(15.7%),2 genotypes in 59 strains (71.1%) and single genotype in only 11 strains(13.2%).The genes of CTX-M-3,TEM-1 and SHV were found co-existent in 9 strains. The strains carrying 2 or 3 ESBL genes were more resistant to antibiotics than those carrying only 1 ESBL gene.Conclusions The genotypes of ESBLs-producing Klebsiella pneumoniae in this hospital are blaTEM,blaSHV,blaCTX-M and blaOXA. Most strains carry 2 or 3 ESBL genes.