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Objective:To investigate the distribution of clustered regularly interspaced short palindromic repeats (CRISPR) in group B Streptococcus (GBS) in the genital tract of women during the third trimester and in infants with invasive infection and its relationship with multilocus sequence typing (MLST) and drug-resistance genes. Methods:This study retrospectively collected 84 GBS strains isolated from pregnant women with GBS colonization and infants with invasive GBS infection who were admitted to Children's Hospital Affiliated to Shanxi Medical University from January 2017 to January 2022. CRISPR, MLST, and drug-resistance phenotype and genes were detected and analyzed using χ 2 test or Fisher exact probability method. MEGA11 was used to construct a dendrogram. Results:There were ten sequence typing in the 84 GBS strains and ST10 was the dominant one (46.4%). GBS was sensitive to penicillin, and its resistance rates to erythromycin (75.0%) and clindamycin (73.8%) were high. Among the 17 invasive GBS strains, ST10 had 100% resistance to erythromycin, clindamycin, and levofloxacin. CRISPR1 gene was amplified in 62 strains (73.8%). CRISPR1-positive strains had a significantly higher proportion of ST10 [56.5%(35/62) vs 18.2%(4/22), χ 2=9.56, P=0.002] and ermB, gyrA, parC [54.8%(34/62) vs 22.7%(5/22), 67.7%(42/62) vs 36.4%(8/22), 71.0%(44/62) vs 36.4%(8/22); χ 2=6.73, 6.64, and 8.25, all P<0.05], and a lower proportion of ermA [6.5%(4/62) vs 31.8%(7/22), χ 2=7.09, P=0.008] than CRISPR1-negative strains. Conclusions:ST10 is the main GBS genotype among the colonized microbiota the genital tract of pregnant women and in infants with invasive GBS infection, which is also a dominant type in CRISPR1-positive strains. GBS is sensitive to penicillin and CRISPR1 gene is linked to the spread of some drug-resistance genes.
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Objective@#To investigate the prevalence and resistance changes of carbapenem-resistant Enterobacteriaceae (CRE) strains isolated from children patients of Chinese Bacterial Resistance Surveillance Network (CHINET) from 2005 to 2017.@*Methods@#Antimicrobial susceptibility testing was carried out by disk diffusion method (KB method) and automated systems. Results were analyzed according to the Clinical and Laboratory Standards Institute (CLSI) 2017 edition standards.@*Results@#Among the 4 481 CRE clinical strains, the overall prevalence of CRE in children was 6.4%, including 8.8% in neonatal period, 7.3% in infancy, 3.8% in early childhood, 4.0% in preschool, 4.7% at school age and 7.4% of puberty. The CRE prevalence of citrobacter spp. remained stable in 2005-2017, whereas other bacteria showed an upward trend, which was higher than that of the adult group (P<0.01). Among the 4 481 CRE strains, there were 2 905 strains of Klebsiella spp. (64.8%), 813 strains of Escherichia coli (18.1%), 549 strains of Enterobacter spp.(12.3%), and 65 strains of Citrobacter spp.(1.5%). Among the 4 481 CRE strains, 20.7%, 13.3%, and 11.8% were from the intensive care unit (ICU), neonatal department and internal medicine wards, respectively. Specimens were distributed as respiratory (42.8%), urine (26.3%), and blood (14.9%). The results of antimicrobial susceptibility testing exhibited that the CRE strains were highly resistant to most commonly used antimicrobial agents in clinical practice, such as imipenem, meropenem and ertapenem, as well as penicillins and cephalosporins, etc.@*Conclusion@#The prevalence of CRE strains in children is increasing year by year, and their antimicrobial resistance to common antibacterial agents in clinical practice is extremely serious, to which serious attention needs to be paid. According to the results of antimicrobial susceptibility testings, the antibacterial agents should be rationally selected to effectively control the spread of CRE.
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Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.
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Objective@#To investigate the antibiotic resistance status of Streptococcus pneumoniae isolates from hospitalized children in Shanxi Children′s Hospital.@*Method@#E-test and Kirby-Bauer methods were applied to determine drug sensitivity of the isolates collected from the body fluid specimens of hospitalized children in Shanxi Children's Hospital from January 2012 to December 2014. The antimicrobial sensitivity and minimum inhibitory concentration (MIC) of Streptococcus pneumoniae to the conventional antibiotics were analyzed, in order to compare the annual trends of non-invasive isolates, while the differentiation of sensitivity from specimens. The comparison of rates was performed by Chi-squared test and Fisher's exact test.@*Result@#A total of 671 isolates of streptococcus pneumoniae were obtained, which could be divided as non-invasive isolates(607), invasive isolates from non-cerebrospinal fluid(non-CSF)(40) and invasive isolates from cerebrospinal fluid(CSF)(24). The antimicrobial sensitivity(isolates(%)) of the 671 isolates were respectively vancomycin 671(100.0%), linezolid 671(100.0%), levofloxacin 665(99.1%), penicillin 595(88.7%), ceftriaxone 516(76.9%), cefotaxime 512(76.3%), sulfamethoxazole-trimethoprin(SMZ-TMP) 103(15.4%), clindamycin 28(4.2%), tetracycline 26(3.9%), erythromycin 12(1.8%). From 2012 to 2014, the susceptibility rates of non-invasive isolates to penicillin every year were 95.0%(96/101), 97.3%(110/113), 87.3%(343/393), respectively, and there was significant difference among the three years(χ2=13.266, P<0.05), and the values of MIC50, MIC90 and the maximum values of MIC(mg/L) of penicillin were 0.064, 2.000, 6.000 in 2012, which grew up to 1.000, 3.000, 16.000 in 2014. There was no significant difference in the susceptibility rate of non-invasive isolates to ceftriaxone and cefotaxime during these three years, (χ2=1.172, 1.198, both P>0.05). On the other hand, the values of MIC50, MIC90 and the maximum value of MIC(mg/L) of ceftriaxone and cefotaxime both increased from 0.500, 2.000, 8.000 in 2012 to 0.750, 4.000, 32.000 in 2014. There was no significant difference in the susceptibility rate of non-invasive isolates to the rest antibiotic. Based on the same examining standard of CSF, the antimicrobial sensitivity(isolates(%)) of the non-invasive isolates to ceftriaxone, cefotaxime, SMZ-TMP were respectively 281(46.3%), 278(45.8%), 78(12.9%), were significantly lower than the susceptibility rate of the invasive isolates from non-CSF (28(70%), 28(70%), 14(35%), χ2=8.453, 8.817, 15.094, all P<0.012 5), and lower than the invasive isolates from CSF (18(75%), 18(75%), χ2=7.631, 7.905, P<0.012 5; 11(45.8%), P=0.001). The sensitivity of the isolates to the rest antibiotics were similar(P>0.05).@*Conclusion@#More than 95.0% strains of the streptococcus pneumoniae isolates from the hospitalized children in Shanxi Children's Hospital were sensitive to vancomycin, linezolid, levofloxacin, and the susceptibility rate of penicillin, ceftriaxone, cefotaxime were 88.7%, 76.9%, 76.3%. However, less than 20.0% of streptococcus pneumoniae were sensitive to erythromycin, clindamycin, SMZ-TMP and tetracycline. The susceptibility rate of penicillin of non-invasive Streptococcus pneumoniae declined by these years, and the differences to ceftriaxone and cefotaxime can be neglected, but the values of MIC50, MIC90 and the maximum value of MIC of all were linearly rising. The susceptibility rate of antibiotics to ceftriaxone and cefotaxime of the non-invasive isolates was lower than the invasive isolates.
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Objective Up to now, the role of Brucea in early embryonic development of mice and its mechanism is still unclear.This paper aims to explore the role of Brusatol in mouse early embryonic development and its possible mechanism.Methods 100 kunming rats of clean grade(80 female rats and 20 male rats) were divided into 6 group: negative control group(no DMSO)、blank control group(culture in fresh CM with equal DMSO)、20nmol/L brusatol treated group、50nmol/L brusatol treated group、100nmol/L brusatol treated group、200nmol/L brusatol treated group(A solution of Brusatol was diluted in CM to concentrations of 20, 50, 100 or 200nmol/L.).Each group used an average of 20 embryos each time, repeated 4 times.Fertilized eggs after cultured 24h, 48h,72h, 96h were respectively 2-cell stage, 4-cell stage,morula and blastocyst stage..The embryo development rate was observed in the culture medium and the optimal concentration was selected, the embryos were collected to analysis the subcellular localization of the Nrf2 by immunofluorescence.The mRNA expression level of Cyclin B, CDK1 and the protein expression of Nrf2 were detected by Q-PCR and western blot respectively.Results In 4-cell stage, the embryo development rates of 20、50、100nmol/L brusatol treated groups[(75.0±2.8)%、(30.4±7.5)%、(4.2±5.9)%] significantly reduced compared with the negative control group[(93.0±2.8)%]、blank control group[(90.9±1.2)%].In morula stage, compared with blastocyst rates of negative control group、blank control group [(83.5±2.1)%、(84.2±1.2)%], 50nmol/L brusatol treated group[(19.3±13.1)%] decreased obviously [(79.00±0.06)% vs 100%, P<0.05].In the cellular immunofluorescence assay, the expression of Nrf2 protein in 50nmol/L brusatol treated group was lower than blank control group(P<0.05).We further found that 50nmol/L brusatol treated group decreased more mRNA levels of Cyclin B[(59.5±9.2)%] and CDK1[(56.0±1.4)%] than blank control group(100%) in G2/M phase(P<0.05).Conclusion In this study, Brusatol mainly affects the cell cycle transformation from G2 to M phase dependent on Cyclin B-CDK1, further inhibiting the development of the embryo through down-regulating Nrf2.
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Objective To investigate the change in distribution and antimicrobial resistance of pathogens from blood culture of children,and provide a basis for treatment of bloodstream infection.Methods Pathogens isolated from blood culture of hospitalized children between January 2009 and December 2013 were divided into group 2009-2011 and 2012-2013.Distribution and antimicrobial susceptibility of pathogens were analyzed.Results From 2009 to 2013,a total of 48 455 blood specimens were taken for culture,2 730 pathogenic bacteria were isolated,positive rate was 5.63%.The positive rate of blood culture decreased year-by-year (χ2 =415.30,P <0.01 ).Of 2 730 iso-lates of pathogenic bacteria,gram-positive bacteria,gram-negative bacteria,and fungi accounted for 80.37% (n =2 194),18.68%(n=510),and 0.95%(n=26)respectively.The difference between two groups of pathogenic bacte-ria was significant(χ2 =180.334,P <0.001).Susceptibility rates of gram-positive cocci to vancomycin,linezolid and teicoplanin were all 100%,resistance rates of coagulase-negative Staphylococcus and Staphylococcus aureus to cip-rofloxacin,compound sulfamethoxazole and tetracycline all decreased.Susceptibility rates of gram-negative bacilli to imipenem,meropenem and amikacin were all≥97.50%,susceptibility rate of Klebsiella pneumoniae to levofloxacin was 100%;Of cephalosporins,Escherichia coli and Klebsiella pneumoniae had high resistance except ceftazidime and cefepime.Conclusion Distribution of pathogens from blood culture of children in 2009-2013 changed signifi-cantly,pathogens have high resistance to commonly used antimicrobial agents,more attention should be paid to the monitor of pathogens from blood culture and pathogenic antimicrobial resistance.
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OBJECTIVE To investigate the major pathogenic bacteria and drug resistance in the infantile septicemia and to provide laboratory evidence for clinical diagnosis and treatment. METHODS The venous blood plate was used. RESULTS Totally 328 isolated strains were assayed with French Bio-Merieux API System.Of them,203 strains of coagulase negative Staphylococcus(CNS),being 61.9%.115 strains(56.6%) were(S.epidermidis).45 strains(22.1%) were S.haemolyticus,and 43 strains(21.1%) were S.lugdunensis.The isolated rate of meticillin resistant coagulase negative Staphylococcus(MRCNS) was 35.5%.The drug test for MRCNS showed multiple drug-resistance. CONCLUSIONS MRCNS is the major pathogen in infantile septicemia.The detectable rate of MRCNS is high.Glycopeptide antibiotics are the first-choice drugs for MRCNS infection.