Comparison of separating gel and HB&L pretreatment methods for rapid identification of the pathogenic bacteria in positive blood culture samples by MALDI-TOF MS / 中华检验医学杂志

Objective:To evaluate the identification rate of separating gel or HB&L pretreatment methods of MALDI-TOF-MS, thereby to provide a new idea for the rapid and accurate identification of pathogens of bloodstream infections in daily clinic practice.Methods:A total of 149 alarmed positive blood culture samples of single bacterial infection by routine laboratory methods were collected between January to December 2020 from the Sixth Medical Center, Chinese PLA General Hospital. Samples were pretreated with the separation gel accelerating tube method or the HB&L microbial culture system, followed by direct MALDI-TOF MS bacterial identification, the identification rates of the two pretreatment methods were compared and results from the traditional method were used as the standard control.Results:Among the 149 positive blood culture samples, 47.0% (70/149) were gram-negative (G -) bacteria and 53.0% (79/149) were gram-positive (G +) bacteria. Identification rate of G -strain level was 78.6% (55/70) by serum separation gel coagulation tube method and 91.4% (64/70) by HB&L microbial culture system, the difference was statistically significant ( P=0.033). Identification rate of G +strain levels was 73.4% (58/79) by serum separation gel coagulation tube method and 87.3% (69/79) by HB&L microbial culture system, the difference was statistically significant ( P=0.028). For G -bacteria in the range of 3.000-2.300, the identification rate was 22.9% (16/70) by serum separation gel accelerating tube method and 38.6% (27/70) by the HB&L microbial culture system, the difference was statistically significant ( P=0.044). For G +bacteria in the range of 3.000-2.300, the identification rate was 19.0% (15/79) by serum separation gel accelerating tube method and 34.2% (27/79) by the HB&L microbial culture system, the difference was statistically significant ( P=0.031). Conclusion:The identification rate of HB&L microbial culture system is higher than that of serum separation gel coagulation tube method. Direct MALDI-TOF MS identification of pathogenic bacteria in positive blood culture samples after pretreatment is feasible in daily clinical practice.

Analysis on changes of drug resistance and class Ⅰ integron in clinically isolated Pseudomonas aeruginosa during 2013-2015 / 国际检验医学杂志

Objective To investigate the changes of drug resistance and class Ⅰ integron in clinically isolated Pseudomonas aeruginosa(PA) in our hospital form January 2013 to December 2015.Methods Clinically isolated PA strains were divided into the 3 time periods of 2013,2014 and 2015.Their resistance to 22 commonly used antibacterial drugs was investigated by adopting the VITEK-2;200 strains were randomly selected from the isolated strains during these 3 time periods.Class Ⅰ integron was detect by PCR.Results The detected PA in these 3 time periods had 366,437 and 520 strains respectively.The drug resistance of Pseudomonas aeruginosa to 22 commonly used antibacterial drugs was remarkably increased(P<0.05),especially in ICU.The detection rate of class Ⅰ integron positive bacteria was gradually increased year by year,moreover the drug resistance rate of class Ⅰ integron positive bacteria was significantly higher than that of class Ⅰ integron negative bacteria (P<0.01).Conclusion The drug resistance rate of PA in this hospital is higher.The proportions of multi-drug resistance and classⅠ integron are significantly increased.The hospital infection detection and drug-resistant bacterial monitoring should be strengthened to further standardize the use of antibacterial drugs.

Analysis on distribution characteristics and drug resistance of Klebsiella pneumoniae in a hospital during 2011-2015 / 国际检验医学杂志

Objective To investigate the clinical distribution situation and drug resistance change of Klebsiella pneumoniae in the Navy General Hospital during 2011‐2015 in order to provide reference for rational use of antibacterial agents in clinic .Methods The clinically isolated Klebsiella pneumoniae in this hospital during 2011‐2015 were selected and performed the analysis on the de‐tection rate ,department distribution ,specimens source ,resistance of antibacterial drugs and change trend of resistance to carbapen‐em antibacterial drugs .Results The number the detected Klebsiella pneumoniae strains and isolation rate during 2011 -2015 showed an increasing trend year by year ,the specimens sources were mainly from 10 departments of intensive care units(ICU) ,hy‐perbaric oxygen department ,respiratory department ,radiation oncology department ,kidney disease department ,etc .;the submitted specimens were dominated by sputum and urine ,accounting for 59 .7% and 21 .4% of submitted specimens ;the drug resistance of Klebsiella pneumoniae during 2011‐2015 showed the increasing trend year by year .Klebsiella pneumoniae had higher resistance rates to piperacillin ,ampicillin ,ampicillin/sulbactam and cefuroxime and had lower resistance rate to amikacin ,imipenem ,meropen‐em and tobramycin ;the resistance rates to imipenem and meropenem were increased year by year ,and pan‐drug resistant Klebsiella pneumoniae showed a rapidly rising trend .Conclusion The drug resistance of Klebsiella pneumonia is serious ,especially carbapene‐ms‐resistant Klebsiella pneumoniae is significantly increased in the recent years ,therefore its drug resistance monitoring should be strengthened for guiding rational drug use in clinic .

Analysis on the distribution of pathogens in intensive care units and their drug resistance / 国际检验医学杂志

Objective To investigate the distribution of pathogens in intensive care units (ICU ) and their drug resistance . Methods 668 strains of pathogens isolated from specimens from ICU were collected .VITEK 2 Compact automated microbial iden-tification and susceptibility analyzer was utilized to conduct the antimicrobial susceptibility tests .Kirby-Bauer disk diffusion suscep-tibility test(K-B) was employed to conduct the antimicrobial susceptibility test for Gram-negative bacteria cefoperazone/sulbactam . Results 668 strains of pathogens were derived from sputum [434 (65 .0% )] ,blood[83(12 .0% )] ,urine[88(13 .0% )] ,drainage [14(2 .0% )] ,secretions[14(2 .0% )] and other[35(5 .2% )] .Acinetobacter baumannii was the major detected pathogen in Gram-negative bacteria and the resistance rates were over 50% toward other drug excepting levofloxacin ,sulfamethoxazole and amikacin . Staphylococcus Staphylococcus was the major detected pathogen in Gram-positive bacteria and it showed good sensitivity toward ni-trofurantoin ,quinupristin/dalfopristin ,tigecycline and vancomycin .Candida albicans demonstrated the highest detection rate in fun-gi .Conclusion ICU pathogens have drug resistance in serious condition ,and pathogens and drug resistance monitoring should be strengthened .

Drug Resistance of 326 Pathogen Strains in Blood Culture / 中华医院感染学杂志

OBJECTIVE To investigate the distribution and drug resistance of pathogenic bacteria in blood culture,and provide a basis for clinical treatment.METHODS The blood samples were poured into the blood culture bottles of Beijing Botai Technique Development Center,and cultured with BacT/Alert 3D automated blood culture system.Isolated bacteria were identified by the VITEK system.Drug sensitivity was tested by the BIOMIC.RESULTS From Jan 2003 to Dec 2007,607 strains of pathogenic bacteria were isolated from 4116 clinic blood specimens,the positive rate was 14.8%,Gram-negative bacteria were the most common pathogens then Gram-positive bacteria and fungi.The sensitivity of Gram-negative bacteria to imipenem/cilastatin(TPM) was the best,the next was FEP;the sensitivity of Gram-positive bacteria to teicoplanin(TCN) was the best,Second was VAN.CONCLUSIONS Drug resistance of isolated pathogenic bacteria in blood cultures is very serious.Monitoring the change of pathogens and trends of drug resistance is very important in guiding the clinical use of drug.