Diagnosis of common blood stream infection pathogens based on central homo-sequence primer by multiplex PCR combined with MALDI-TOF MS / 中华检验医学杂志

Objective:Based on the high-throughput detection technique of multiplex PCR combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, constructing the characteristic SNP profiles of different strains, and establishing a rapid, accurate and highly sensitive method for the diagnosis of bloodstream infection pathogens.Methods:Seven kinds of pathogens such as common Escherichia coli were selected as target. The multiple PCR reaction conditions was optimized, and the characteristic peaks of each target bacteria were detected by MALDI-TOF MS to establish the joint detect system. Common primer pairs and central homo-sequence primer pairs were designed to analyse the formation of primer dimer. Using simulated bacterial infection blood samples with detection system to determine specificity and sensitivity. One hundred and fifty blood samples from suspected bacteremia patients were collected from June to September 2020 in a hospital in Beijing, and the identification results were compared to traditional identification method of clinical application that are using χ 2 test. Results:The cycle threshold (Ct) value of the central homo-sequence primers that were designed were more than 38, with a delay of 6-10 cycles. The joint mass spectrometry detection system could detect seven kinds of bacteria divided into two groups at the same time. The target bacteria can be detected specific product of the peak, and the clinical strains other than the target strains only had primer peaks. All maps had non-specific miscellaneous peaks. The sensitivity of Escherichia coli could reach 50 CFU/ml, and the detection limit of other bacteria was 100 CFU/ml. The detection results of 150 patients showed that 46 cases were positive by traditional method. The positive rate was 30.67% (46/150), including two cases of mixed infection. Forty-eight cases were positive by mass spectrometry, and the positive rate was 32.0% (48/150), including three cases of mixed infections. The negative coincidence rate was 100% (101/101). The comparison of the two methods showed that the P=0.625>0.01, the Kappa=0.938, the sensitivity and specificity was 97.82%(45/46) and 97.11%(101/104), respectively. There was no significant difference between the two methods, and the results of nucleic acid mass spectrometry could also be used in clinic. Conclusions:The established detection system can not only quickly and accurately detect seven common pathogens causing bloodstream infection, and effectively shorten the time needed for traditional culture and identification, but also can detect multiple bacterial mixed infections at the same time to make up for the possibility of missed detection. Besides, the method can also be used to identify other bacteria.

Antibacterial treatment scheme and risk factors of bloodstream infection with carbapenem-resistant Klebsiella pneumoniae / 中国综合临床

Objective:To investigate the relationship between antibacterial treatment scheme and prognosis, and to analyze the mortality risk factors of bloodstream infection with carbapenem-resistant Klebsiella pneumoniae(CRKP).Methods:A retrospective case-control study was conducted. The CRKP isolated from clinical venous blood samples in the First Medical Center, Chinese PLA General Hospital between January 1, 2013 and December 31, 2018(not included from January 1, 2016 to December 31, 2017) was collected. According to relevant standards, a total of 50 patients with bloodstream infection with CRKP were included. The patients were divided into death (19 cases) or survival (31 cases) group according to their hospitalization outcomes, and clinical data and antibacterial treatment scheme after infection were collected. The clinical features of the two groups and the correlation between different antibacterial treatment regimens and prognosis were compared. Logistics regression model was used to analyze the risk factors for death in CRKP-infected patients.Results:The all-cause mortality rate of patients with CRKP bloodstream infection during hospitalization was 38%(19/50). The age ((66.89±18.13) vs. (55.06±14.39) years old, t=2.555, P=0.014), charlson's comorbidity index ((6.11±2.87) vs. (3.19±1.97), t=4.256, P<0.001) of the death group was higher than that of the survival group. The proportion of patients with chronic obstructive pulmonary disease (42.1%(8/19) vs. 3.2%(1/31), χ2=9.574, P=0.002), Charlson's comorbidity index ≥5 (68.4%(13/19) vs. 22.6%(7/31), χ2=10.314, P=0.001), septic shock (36.8%(7/19) vs. 6.5%(2/31), χ2=5.456, P=0.020), source of lung infection (36.8%(7/19) vs. 9.7%(3/31), χ2=3.868, P=0.049) was higher in death group than those in survival group. Kaplan-meier survival curve showed that the 30-day mortality of appropriate targeted treatment was lower than that of inappropriate targeted treatment ( χ2=8.138, P=0.004). Multivariate analysis showed that septic shock ( OR=56.363, 95% CI: 4.309-737.273, P=0.002) and charlson's comorbidity index ≥5 ( OR=18.605,95% CI: 1.813-190.896, P=0.014) were independent risk factors for mortality in patients with bloodstream CRKP infection. Conclusion:Appropriate targeted therapy can reduce 30-day mortality in patients with CRKP bloodstream infection. In order to reduce the risk of mortality, we should prevent the occurrence of septic shock and strengthen the diagnosis and treatment of patients with Chalson's comorbidity index ≥5.

Application and prospect of next-generation sequencing in detection of infectious pathogens / 中华检验医学杂志

In recent years, with the rapid development and the continuous simplification of operation process, and the growth of detection flux, and the reduction of detection cost, high-throughput sequencing (HTS), also known as next-generation sequencing (NGS), has shown some technical advantages in the detection of infectious pathogens and been used widely. The direct strategies of clinical specimens using NGS technology include target amplification sequence and metagenomic sequence (mNGS), which are more widely used. mNGS is benefit to determine the type and relative number of microorganisms in clinical samples by directly detecting the pathogenic nucleic acid. It can help to determine the pathogen of infection without culturing the pathogenic bacteria. The current testing services are mostly provided by professional sequencing companies. The inspection and evaluation of the detection results and their application value should be carried out from the following technical indicators: sequencing depth, number of reads, coverage, confidence and relative abundance. In addition, the use of NGS data can also accurately analyze the biological characteristics of pathogens (such as drug susceptibility), which has been well used in the detection of Mycobacterium tuberculosis. In the future, the rapid development of NGS in detection technology, detection process, detection performance, detection results application and other aspects will bring great technology and application innovation to clinical infection pathogen detection, and will also bring great challenges and development opportunities to relevant practitioners.

Research progress in epidemiological characteristics of carbapenem-resistant Enterobacteriaceae / 中华微生物学和免疫学杂志

Carbapenem-resistant Enterobacteriaceae (CRE) are defined as bacteria of the Enter-obacteriaceae family exhibiting resistance to any carbapenem antibiotics. As some of the most common patho-gens, Enterobacteriaceae spread worldwide and often cause large-scale outbreaks and transmission in medical institutions or regions. Increasing resistance of these bacteria to clinically common-used anti-infective drugs results in more and more treatment failure and brings enormous challenges to nosocomial infection control and anti-infection treatment. Understanding the distribution and transmission of CRE is of great significance for controlling the spread of such pathogens. This article reviews the progress in the distribution and epidemic characteristics of CRE. Klebsiella pneumoniae carbapenemase ( KPC)-producing Klebsiella pneumoniae (K. pneumoniae) was first isolated in the United States and has become the predominant species of CRE worldwide. In recent years, KPC-2- and KPC-3-producing K. pneumoniae are widely spread in many regions. NDM-1 has been detected worldwide since it was isolated from Escherichia coli (E. coli) and K. pneumoniae in India and Britain in 2010 and become the second most common carbapenemase produced by Enterobacteri-aceae other than KPC. OXA-48, which was first detected from a carbapenem-resistant K. pneumoniae in 2004, has weak hydrolytic activity against carbapenems. Large-scale outbreaks caused by OXA-48-producing Enterobacteriaceae have occurred in many countries such as Turkey, Spain, Morocco and Tunisia. In China, the predominant species of CRE is KPC-producing K. pneumoniae mainly belonging to the sequence type 11 (ST11). In addition, KPC-producing Klebsiella oxytoca (K. oxytoca), E. coli, Enterobacter cloacae (E. clo-acae), Citrobacter freundii (C. freundii), Serratia marcescens, Proteus mirabilis (P. mirabilis), Enterobact-er fluvialis (E. fluvialis) and Morgan morganii have also been reported. The prevalent NDM-producing spe-cies isolated in China are E. coli and K. pneumoniae. Moreover, blaNDM is also carried by E. cloacae, K. oxy-toca, C. freundii, P. mirabilis and Enterobacter aerogenes (E. aerogenes). Small-scale outbreaks caused by OXA-48-producing K. pneumoniae have only been reported in Beijing and Taiwan in China.

Study on the relatedness of homology of carbapenem-resistant Klebsiella pneumoniae using MALDI-TOF MS / 中华检验医学杂志

Objective To evaluate the ability of Matrix-assisted laser desorption ionization-time of flight mass spectrum (MALDI-TOF MS) on homology analysis of carbapenem-resistant Klebsiella pneumoniae(Carbapenemase-Resistant K. pneumoniae, CRKp). Methods During January 2017 to December 2017, a total of 57 strains isolatedfromChanghai Hospital, Shanghai and 36 strainsfrom Urumqi First Hospital, Xinjiang were included for retrospective study. Inclusion criteria:strains which resistant to one of the carbapenems and with more than 100 peaks in identification mass spectrum. A total of 39 isolates were selected and divided into three groups according to the PFGE typing results:(1) Highly homologous group (17 strains with blaOXA-48 gene); (2) Moderate homology group (16 strains with blaKPC gene); (3)The non-homology group (8 strains with other resistance mechanisms). Mass spectrometry results were analyzed using BioNumeric and the two classification methods in SARAMIS, respectively.The PFGE analysis results were regarded as standard when evaluate the reliability of the other three analytical methods. Results Forhighly homologous group, the analysisresults of KA-A type dientical mass by two classification methods in SARAMIS were accord with PFGE,and the identity mass value is>80％, the similarity is>85％. However, for non-homologous group, the identity mass value is<80％, the similarity is<85％ when compared with PFGE, which indicated that the method based on MALDI-TOF MS was not premium for this group of strains. For moderate homologous strains,the results of two SARAMIS methods for KC-A type havepoor consistency with PFGE, for the identity mass value is<70％, the similarity is<90％. Conclusions Based on MALDI-TOF MS using BioNumeric software and SARAMIS database software could be regarded as a screening method for phylogenetic analysis among CRKp strains with high homology. While, it should not be applied to evaluate homology of the strains with genetic diversity for lacking stability.

Short-term clinical outcomes and second-look arthroscopic findings of high tibial osteotomy combined with medial meniscus posterior root repair / 中华骨科杂志

Objective@#To investigate the clinical outcomes and second-look arthroscopic findings after high tibial osteotomy (HTO) combined with medial meniscus posterior root (MMPR) repair.@*Methods@#Twenty-five patients who underwent HTO combined with MMPR repair were subjected to second-look arthroscopy and retrospectively analyzed. Biplane HTO combined with MMPR repair was performed on these patients. Arthroscopic transtibial pullout repair was employed to repair the MMPR. The relative degree of the medial meniscus extrusion (MME) were measured. Cartilage regeneration and the healing of MMPR were evaluated at the time of second-look arthroscopy. Clinical outcomes were assessed based on Hospital for Special Surgery (HSS) scores and Lysholm scores.@*Results@#The MMPRs were completely healed in 12 cases (48%), partially healed in 9 cases (36%), healed with scarring in 3 cases (12%), and no healed in 1 case (4%). Follow-up duration was 13.04±1.06 months (12-16 months). There were no statistically significant differences in the Kellgren-Lawrence classifications of the cases before and after surgery (χ2=0.786, P=0.675). The relative position of the mechanical axis of the lower extremity through the tibial plateau was 19.88%±6.44% preoperatively and 58.68%±7.71% after operation with significant difference (t=-18.561, P<0.001). The Lysholm scores was increased significantly from 34.76±3.62 points to 82.08±4.35 points after operation (t=-52.717, P<0.001). The HSS scores was increased significantly from 33.52±6.48 points to 81.52±4.79 points after operation (t=-38.685, P<0.001). The degree of MME was changed from 51.12%±13.55% to 50.48%±15.15% without statistical difference (t=0.550, P=0.588) . The comparison between different degrees of healing groups revealed no statistical differences in all variables (P>0.05). The comparison between different degree of cartilage regeneration groups revealed no statistical differences in all variables (P>0.05).@*Conclusion@#HTO combined with MMPR repair can effectively improve the lower limb alignment and patients' symptoms with a satisfactory healing rate of MMPR. The effects of post-root repair after a short period is not obvious. The longer-term clinical effects is worthy of further observation.

Short-term clinical outcomes and second-look arthroscopic findings of high tibial osteotomy combined with medial meniscus posterior root repair / 中华骨科杂志

Objective To investigate the clinical outcomes and second-look arthroscopic findings after high tibial osteotomy (HTO) combined with medial meniscus posterior root (MMPR) repair.Methods Twenty-five patients who underwent HTO combined with MMPR repair were subjected to second-look arthroscopy and retrospectively analyzed.Biplane HTO combined with MMPR repair was performed on these patients.Arthroscopic transtibial pullout repair was employed to repair the MMPR.The relative degree of the medial meniscus extrusion (MME) were measured.Cartilage regeneration and the healing of MMPR were evaluated at the time of second-look arthroscopy.Clinical outcomes were assessed based on Hospital for Special Surgery (HSS) scores and Lysholm scores.Results The MMPRs were completely healed in 12 cases (48％),partially healed in 9 cases (36％),healed with scarring in 3 cases (12％),and no healed in 1 case (4％).Follow-up duration was 13.04±1.06 months (12-16 months).There were no statistically significant differences in the Kellgren-Lawrence classifications of the cases before and after surgery (x2=0.786,P=0.675).The relative position of the mechanical axis of the lower extremity through the tibial plateau was 19.88％±t6.44％ preoperatively and 58.68％±17.71％ after operation with significant difference (t=-18.561,P ＜ 0.001).The Lysholm scores was increased significantly from 34.76±3.62 points to 82.08±4.35 points after operation (t=-52.717,P ＜ 0.001).The HSS scores was increased significantly from 33.52±6.48 points to 81.52±4.79 points after operation (t=-38.685,P ＜ 0.001).The degree of MME was changed from 51.12％± 13.55％ to 50.48％± 15.15％ without statistical difference (t=0.550,P=0.588).The comparison between different degrees of healing groups revealed no statistical differences in all variables (P ＞ 0.05).The comparison between different degree of cartilage regeneration groups revealed no statistical differences in all variables (P ＞ 0.05).Conclusion HTO combined with MMPR repair can effectively improve the lower limb alignment and patients' symptoms with a satisfactory healing rate of MMPR.The effects of post-root repair after a short period is not obvious.The longer-term clinical effects is worthy of further observation.

Application of MALDI-TOF MS in identification of clinical Aspergillus / 中华检验医学杂志

Objective@#To discuss the application of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) in the identification of Aspergillus and evaluate its performance.@*Methods@#the clinical isolates of Aspergillus collected from May 2017 to March 2018 in PLA General Hospital were identified by VITEK MS V3.0 and the results were analyzed. The ITS sequencing resultswere used as the gold standard.@*Results@#It identified 9 Aspergillus species (including 12 Aspergillus species in total) through the V3.0 database, accounting for 86.24% of the total clinical isolates. The identification rate by VITEK MS was 91.49% with 16.51% was not identified. The coincidence rate of genus was 93.62%, of which only two Aspergillus versicolor were identified to the level of the genus. According to the confidence level analysis, 88.30% of the strains obtained more than 99% of the identification rate. 13.83% of the strains did not have the identification results for the first time, with the error rate of 3.19%. After secondary extractions, the percentage of unidentified strain was reduced to 6.38%, and the identification error rate was reduced to 2.13%. Combined with traditional identification and VITEK MS identification, the correct rate of strains identification was 98.94% on genus level, and was 93.62% on species level. The influence of other fungi on Aspergillus identification was 0%.@*Conclusion@#As a powerful supplement to the traditional identification method, MALDI-TOF MS showed a lot of convenience when applied in the identification of Aspergillus, which improves the identification accuracy and the identification ability for fungi in laboratory.(Chin J Lab Med, 2018, 41: 577-582)

Progress in the studies of virulent characteristics of uropathogenic Escherichia coli / 中华检验医学杂志

Uropathogenic Escherichia coli ( UPEC) is the most common pathogen causing urinary tract infection ( UTI).Various virulent factors of UPEC involved in the pathogenic process of UTI , including adhesins, iron uptake-related factors, protectins, and toxins.Adhesion factors can help UPEC to adhere to the surface of the epithelial cell in the host urinary tract.Iron ion acquisition factors can help the pathogen to get iron from the host body , and then multiply and cause disease.Various toxins produced by the pathogen can cause damage to the host epithelial cells and release of nutrients and other nutritional factors that help UPEC to survive and grow.Protectins can protect UPEC from the host complement system mediated bactericidal effect and the phagocytosis of phagocytic cells.In this review , the most recent research progress on the various virulence characteristics of UPEC will be discussed.

Study on the correlation between old ACL injury with medial meniscal tears and posterior slope of tibial plateau / 中华骨科杂志

Objective To explore the correlation between old anterior cruciate ligament (ACL) injury with medial menis-cal tears and posterior slope of tibial plateau. Methods Between July 2014 and February 2016, retrospective analyzed 177 pa-tients diagnosed with old ACL injury (injured to surgery time>3 months) who has been underwent arthroscopic treatment. 93 pa-tients included in this study contained 65 male and 28 female,the average age was (32.36±4.50) years old (ranged from 21 to 44 years). All patients were diagnosed with ACL rupture and no associated medial meniscus tear by MR examination at the time of in-jury and before operation. Posterior slope angle of tibial plateau was measured via MR. The patients were divided into two groups according to the presence of medial meniscus tear by preoperative MR examination. Statistical analysis was employed to analyze the difference between the two groups of patients's age, body mass index (BMI), posterior slope angle of tibial plateau, gender and side. The patients were divided into group of posterior slope of tibial plateau ≥10° and posterior slope of tibial plateau<10° re-spectively. Statistical analysis was employed to analyze the incidence of concomitant medial meniscus tear between the two groups. Result All 93 patients in this study were followed up for the average of 8.63 ± 3.74 months. 51(51/93, 55%) patients were com-firmed of concomitant medial meniscus tear and 42 (42/93, 45%) patients without medial meniscus tear through MR and arthro-scope. There was no statistical difference between two groups in age (t=0.843, P=0.843), gender (χ2=1.027, P=0.338), BMI (t=0.568, P=0.571) and side (χ2=0.110, P=0.438). There was a certain correlation between the medial meniscal tears and posterior slope angle of tibial plateau in this group and the values were considered statistically significant ( r=0.602, P=0.000). Posterior slope angle of tibial plateau of medial meniscus tear group (10.51°±2.83°) was significantly higher than that in non medial menis-cus tear group (7.39°±4.62°). Values were considered statistically significant .71.15%(37/51) of the patients showed medial meniscus tear in the group of posterior slope of tibial plateau ≥10° , however, only 34.14%(14/42) patients indicated medial meniscus tear in group of posterior slope of tibial plateau<10°, and the difference was statistically significant(χ2=12.677,P=0.000). Con-clusion There is a certain correlation between old ACL injury with medial meniscal tears and posterior slope angle of tibial pla-teau. With the continuous increase of ACL injury time, high posterior slope angle of tibial plateau (≥10°) is more likely to increase the incidence of medial meniscus tear.

Study on the correlation between old ACL injury with medial meniscal tears and posterior slope of tibial plateau / 中华骨科杂志

Objective To explore the correlation between old anterior cruciate ligament (ACL) injury with medial menis-cal tears and posterior slope of tibial plateau. Methods Between July 2014 and February 2016, retrospective analyzed 177 pa-tients diagnosed with old ACL injury (injured to surgery time>3 months) who has been underwent arthroscopic treatment. 93 pa-tients included in this study contained 65 male and 28 female,the average age was (32.36±4.50) years old (ranged from 21 to 44 years). All patients were diagnosed with ACL rupture and no associated medial meniscus tear by MR examination at the time of in-jury and before operation. Posterior slope angle of tibial plateau was measured via MR. The patients were divided into two groups according to the presence of medial meniscus tear by preoperative MR examination. Statistical analysis was employed to analyze the difference between the two groups of patients's age, body mass index (BMI), posterior slope angle of tibial plateau, gender and side. The patients were divided into group of posterior slope of tibial plateau ≥10° and posterior slope of tibial plateau<10° re-spectively. Statistical analysis was employed to analyze the incidence of concomitant medial meniscus tear between the two groups. Result All 93 patients in this study were followed up for the average of 8.63 ± 3.74 months. 51(51/93, 55%) patients were com-firmed of concomitant medial meniscus tear and 42 (42/93, 45%) patients without medial meniscus tear through MR and arthro-scope. There was no statistical difference between two groups in age (t=0.843, P=0.843), gender (χ2=1.027, P=0.338), BMI (t=0.568, P=0.571) and side (χ2=0.110, P=0.438). There was a certain correlation between the medial meniscal tears and posterior slope angle of tibial plateau in this group and the values were considered statistically significant ( r=0.602, P=0.000). Posterior slope angle of tibial plateau of medial meniscus tear group (10.51°±2.83°) was significantly higher than that in non medial menis-cus tear group (7.39°±4.62°). Values were considered statistically significant .71.15%(37/51) of the patients showed medial meniscus tear in the group of posterior slope of tibial plateau ≥10° , however, only 34.14%(14/42) patients indicated medial meniscus tear in group of posterior slope of tibial plateau<10°, and the difference was statistically significant(χ2=12.677,P=0.000). Con-clusion There is a certain correlation between old ACL injury with medial meniscal tears and posterior slope angle of tibial pla-teau. With the continuous increase of ACL injury time, high posterior slope angle of tibial plateau (≥10°) is more likely to increase the incidence of medial meniscus tear.

Application of Lean Six Sigma to optimize the process flow of blood culture positive specimen processing flow / 中华检验医学杂志

Objective To shorten the turn around time of positive blood culture results by optimizing the blood culture positive specimen processing flow.Methods In January 26,2015,the microbiology department started the blood culture positive specimen processing flow optimization project,and applied the Lean Six Sigma method in the microbiological process management.The TAT data of 124 positive blood cultures containing Enterobacteriaceae were collected before and after the start of the project in about two months.We analyzed the turnaround time median,mean and standard deviation and reference Z value,process performance index,millions of error opportunities.We decompose the turnaround time into six time periods to find the key points of the process improvement and the influencing factors,and then put forward the reform measures to optimize the blood culture inspection process.MiniTab17.0 statistical software was used to process capability analysis and double sample t test.Results After the implementation of the project,the average turnaround time of the blood culture was shortened from 77.10 h to 64.03 h,improved by 13.06 h(16.94％).Process performance greatly improved in Ppk value increased from 0.49 to 0.88,the benchmark Z value increased from 1.48 to 2.63.After the improvement,except the positive alarm time of blood culture,the mean of the other decomposition time was significantly shorter than before.Conclusions The application of Six Sigma in process management can greatly improve the work efficiency and process performance.This project can save a lot of manpower,material and financial resources,reduce the waiting,shorten turnaround time,that achieve the desired results.

Research progress of virus-like particles and its application in the prevention and control of infectious diseases / 中华检验医学杂志

Virus-like particles ( VLPs ) are particles formed by one or several structural proteins from viruses with similar outside structure and antigenicity of the native viruses containing no virus genome.VLPs antigen can be produced in yeasts, mammalian cells, plant cells, insect cells and bacteria.VLPs vaccine can induce immune response effectively.Other adjuvant or polypeptide can be integrated into VLPs to construct chimeric vaccines.This review focuses on research progress of virus-like particles and its application in the prevention and control of infectious diseases.

Progress on phenotypic and genotypic characteristics of hypervirulent Klebsiella pneumoniae / 中华临床感染病杂志

Klebsiella Pneumoniae is an important pathogen for various infections clinically,in which hypervirulent Klebsiella pneumoniae (hvKP) mainly causes pyogenic liver abscess.By now,there are no standardized method to identify hvKP strains.hvKP strains are usually with hypermucoviscous phenotype,and the prevailing serotypes and clonal types are K1,K2 and CC23,CC65,respectively.Genes rmpA,magA,alls and kfu contribute to the pathogenicity of hvKP.This paper reviews the identification,clonal types and serotypes,hypermucoviscous phenotype and some other virulent genes of hvKP.

Study on teaching reformation necessity of medical mycology for undergraduates of medical laboratory specialty / 中华医学教育探索杂志

Objective To study the education of medical mycology for undergraduates of medical laboratory specialty and provide a basis for teaching reformation.Method Setting of mycology related courses of medical mycology for undergraduates in 5 medical schools and 85 inspection and technical personnel's detection of fungi in 81 hospitals were investigated through consultation and questionnaire survey.Results More than 140 class hours for medical mycology were arranged in 5 schools,but as to medical mycology,22 class hours in 1 school and less than 10 class hours in 4 schools,the minimum class hours were 5.Although various numbers of Candida and filamentous fungi could be isolated in hospitals investigated,more than half laboratory workers could not identify penicillium,thermally dimorphic fungi,Zygomycetes and Dematiaceous fungi.Conclusion Education on medical mycology for medical laboratory specialty undergraduates is insufficient and the corresponding teaching lacks such content as medically important pathogenic fungi detection methods and identification characteristics.The hospital technical personnel's fungal identification ability cannot meet the situation of increasing fungal infection involved in clinical medicine,so it is necessary to carry out teaching reformation of medical mycology for undergraduates in laboratory medicine,including adding class hours,increasing course contents and so on.

Horizontal transmission of Streptococcus mutans in caries-active preschool children / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze horizontal transmission patterns of Streptococcus mutans among caries-active preschool children for early interventions of dental caries.</p><p><b>METHODS</b>Plaque samples obtained from 20 caries-active preschool children between 4 and 5 years of age were cultured under anaerobic conditions for isolating S. mutans, which were identified by morphological and biochemical analyses and PCR using primers homologous to the surface protein glucosyltransferase B (gtfB). The genotypes of the isolated S. mutans strains were determined by arbitrarily primed PCR (AP-PCR).</p><p><b>RESULTS</b>Of the 200 S. mutans isolates obtained, 19 were excluded by biochemical analysis, and the remaining 181 isolates were identified as S. mutans by PCR with primers of gtfB, showing 37 different genotypes as identified by AP-PCR. Six children were found to carry S. mutans of a single genotype, 11 carried 2 genotypes, 2 had 3 genotypes, and 1 had 4 genotypes; 2 children from different classes were found to carry S. mutans of the same single genotype.</p><p><b>CONCLUSION</b>We identified 37 genotypes of S. mutans in these caries-active preschool children, among whom horizontal transmissions of the strains were not found.</p>

How to strengthen communication between department of microbiology and the clinical departments / 中华检验医学杂志

With the rapid development of clinical laboratory technology and clinical improvement,the discordance between department of microbiology and clinical departments got more and more.Based on the analysis of interface issues existed between them,we discussed and explored how to do a wonderful job to communicate with each other.(Chin J Lab Med,2013,36:375-376)

Preliminary screen of high cariogenicity Streptococcus mutans strains isolated from clinical specimens / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To screen of high cariogenicity Streptococcus mutans (S. mutans) strains isolated from clinical specimens preliminary.</p><p><b>METHODS</b>Acidogenicity, aciduricity, extracellular polysaccharide production and adhesion of 41 strains of S. mutans isolated from clinical specimens were investigated to screen high cariogenicity S. mutans strains.</p><p><b>RESULTS</b>There were different cariogenicity among 41 strains of S. mutans, in which 3 strains of S. mutans had all high ability to produce extracellular polysaccharide, adhere to the saliva-coated hydroxyapatite, produce acid and tolerate acid, indicated there were 3 strains with high cariogenicity S. mutans strains isolated from clinical specimens. Another 3 strains of S. mutans with all low ability to produce extracellular polysaccharide, adhere to the saliva-coated hydroxyapatite, produce acid and tolerate acid indicated they were low cariogenicity S. mutans strains isolated from clinical specimens.</p><p><b>CONCLUSION</b>We may have obtained high cariogenicity S. mutans strains isolated from clinical specimens.</p>

Isolation and identification of Streptococcus mutans strains with different genotype from clinical samples / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To identify Streptococcus mutans (S. mutans) strains from clinical samples.</p><p><b>METHODS</b>Plaque samples from caries-active and caries-free sites on enamel surfaces were obtained and cultivated for S. mutans isolation. Morphology, biochemistry, automatic microorganism analysis system and polymerase chain reaction using primers homologous to surface protein antigen I/II (spaP), glucosyltransferase B (gtfB) and dextranase (dexA) were used to identify S. mutans. Genotype of isolated S. mutans was determined by arbitrarily primed polymerase chain reaction.</p><p><b>RESULTS</b>Forty-six strains of S. mutans were obtained from the 32 subjects and were identified as S. mutans by biochemistry, automatic microorganism analysis system and polymerase chain reaction. Five identical genotypes were found by arbitrarily primed polymerase chain reaction.</p><p><b>CONCLUSION</b>Forty-one strains of S. mutans with different genotype were obtained from clinical samples.</p>

Selection and identification of ssDNA aptamers specific to clinical isolates of Streptococcus mutans strains with different cariogenicity / 南方医科大学学报

<p><b>OBJECTIVE</b>To select and identify ssDNA aptamers specific to Streptococcus mutans strains with different cariogenicity isolated from clinical specimens.</p><p><b>METHODS</b>Subtractive SELEX technology targeting the whole intact cells was used to screen for ssDNA aptamers specific to the clinical isolates Streptococcus mutans strains with different cariogenicity. Radioactive isotope, flow cytometry, gene cloning and sequencing, MEME online software and RNA structure analysis software were employed to analyze the first and secondary structures of the aptamers and identify the screened aptamers.</p><p><b>RESULTS</b>Detection by radioactive isotope showed sufficient pool enrichment after 9 rounds of subtractive SELEX. Flow cytometry showed that the selected aptamers H1, H16, H4, L1, L10 and H19 were capable of binding specifically with highly cariogenic Streptococcus mutans strains but not with strains with a low cariogenicity. The aptamer H19 had the strongest binding capacity to highly cariogenic Streptococcus mutans strains, with a dissociation constant of 69.45∓38.53 nmol/L.</p><p><b>CONCLUSION</b>We have obtained the ssDNA aptamers specific to the clinical isolates of highly cariogenic Streptococcus mutans strains.</p>