Method selection for pretreatment in direct identification of pathogen in positive blood culture by MALDI-TOF MS / 中华检验医学杂志

Bloodstream infection is one of the leading causes of death worldwide. Rapid determination of the primary pathogen is crucial for diagnosis and antibiotic therapy of bacteremia. The application of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) was a major breakthrough in microbiology. This technology is simple, rapid, economical and accurate, which has been introduced into the microbiology laboratory formicroorganism identificationwidely. Recently, MALDI-TOF MS was combined with extraction methods for direct pathogens identificationfrom positive blood cultures. The methods of pathogensextraction from positive blood cultures are crucial for the accuracy of identification. And developing a standard extraction protocolhas become a hot spot of research in recent years. (Chin J Lab Med, 2018, 41: 563-566)

Ciprofloxacin Combined with Amikacin to Reduce Drug-resistant Mutants of Escherichia coli / 中华医院感染学杂志

OBJECTIVE To study whether the ciprofloxacin(CIP)combined with amikacin(AMK)will decrease the drug-resistant mutants of Escherichia coli(ECO)in vitro.METHODS The MIC of CIP and AMK alone was determined by agar plates dilution method,and the combined MIC by checkerboard method.The mutant prevention concentration(MPC)both alone and combined was determined by the method of agar plates dilution method,and then the value of selectiveity index(SI)(MPC/MIC)would be acquired.RESULTS The SI of two antibiotics separatedly were 16(CIP)and 32(AMK).When two antibiotics combined,if the concentration of AMK and CIP reached 2MIC could restrain the mutants.After these two antibiotics combined,the value of SI(MPCcombined/MICcombined)came to be 8(0.008/0.001)and 8(2.0/0.25).CONCLUSIONS Compared with alone,CIP and AMK combined can decrease the MPC and SI to ECO,and have the more effect to AMK.In this way,we can reduce the drug-resistant mutants.

The expression and significance of protein tyrosine phosphatase SHP2 in juvenile rat bacterial meningitis model / 中华传染病杂志

Objective To explore the expression and significance of protein tyrosine phosphatase SHP2 in experimental bacterial meningitis.Methods A juvenile rat bacterial meningitis model was established by direct intraeisternal injection with Streptococcus pneumoniae. Uninfected control animals were mock-infected with sterile saline.The transcription and expression of SHP2 were detected by reverse transcription-polymerase chain reaction(RT-PCR),Western blot and immunohistochemistry techniques respectively at 1,3,7 and 14 days after infection.White blood cell(WBC)count,concentration of tumor necrosis factor-alpha(TNF-α)in cerebrospinal fluid(CSF)were also measured.Variables that were not normally distributed were compared by the Kruskal-Wallis test.Multiple comparison used Student-Newman-Keuls(SNK).The association between variables was assessed by using the Pearson correlation coefficient.Results Compared with uninfected controls,rats with bacterial meningitis showed a significant upregulation of SHP2 at both mRNA and protein levels(F=12.74,P<0.01;F=198,P<0.01).S HP2 mRNA levels peaked at 3 days after infection increasing more than five fold and remained at high levels at 7 days.In parallel,SHP2 protein levels began to increase at 3 days after infection,reaching a maximal increase of nearly nine fold at 7 days and remained at high levels at 14 days. Immunohistochemical analysis of SHP2 expression in the juvenile rat brain demonstrated that SHP2 labelling cells,identified as neuronal and glial cells,widely distributed in the cerebral cortex and the increased immunoreactive cells around the third ventricle were mainly glial cells.In addition,the protein levels of SHP2 and WBC counts were significantly correlated with each other(r=0.77,P<0.01),while there were no significant correlations between levels of SHP2 and TNF-a (r=0.08,P>0.05).Conclusions SHP2 may participate the pathological progress of the bacterial meningitis,restrating the inflammation and accelerating the renovation,so it can be regard as an index to measure the state of the illness.

Antibiotics combined with azithromycin can reduce the drug resistant mutants of pseudomonas aeruginosa in vitro / 中国实用内科杂志

32,16,16.Combined with azithromycin were8,16,16,8.MEM,CAZ,CIP combined with AMK were 1,4,8.AMK combined with CIP were 4.Conclusion Compared with sole,MEM,CAZ,CIP combined with azithromycin can reduce the MPC and SI of antibiotics alone to pseudomonas aeruginosa and restrain the drug-resistant mutants.But the capacity of preventing mutants arise were weaker than combined with AMK.AMK combined with azithromycin can't reduce the SI.But when combined with CIP,the SI of AMK were reduced greatly.

Analysis of central venous catheter related sepsis / 肠外与肠内营养

Objectives: To investigate the distribution of common pathogens and their antibiotic resistance from patiens with catheter related sepsis (CRS).Methods: Catheter bacteria cultrure and antibiotic sensitivity test were performed from 69 patiens with CRS.Results: The common pathogens in CRS were fungi (41.1%),Gram-positive cocci (35.6%)and Gram-negtive bacilli (23.3%). Non-C. albicans species were major pathogen (19/30 stranins).The most strains were staphylococcus epidermidis in Gram-positive cocci and the most of them were Methicillin resistant.No vancomycin resistant strains were found. The Gram negative bacilli were often resistant to third generation cephalosporens.Conclusions: The dorminant pathogens of CRS are fungi and gram positive cocci and we should pay more attention to pathogens of resistence to antibiotics. In order to control CRS, CVC must be used reasonably and shorten the duration of retention.