ABSTRACT
Antimicrobial resistance of Staphylococcus aureus is a main factor for the poor prognosis.In China, the detection rate of Methicillin-resistant Staphylococcus aureus (MRSA) in children is annually increasing, especially the community-acquired MRSA (CA-MRSA). This review discussed molecular characteristics, antimicrobial resistance mechanism and antimicrobial resistance progress of CA-MRSA, and analyzed recent molecular epidemiology and changes of drug resistance to CA-MRSA in children from China, thus providing theoretical basis for the prevention and control of CA-MRSA in children.
ABSTRACT
Objectives:To study the molecular characteristics, virulence gene and resistance profiles of Staphylococcus aureus ( S. aureus, SA) isolates from bloodstream infections (BSI), so as to further understand the molecular characteristics of S. aureus in pediatric patients. Methods:A total of 53 S. aureus strains in bloodstream infections from Shanghai Children′s Hospital between 2016 and 2021 were collected. Antimicrobial susceptibility test were adopted by instrumental and disk diffusion method. Thirty-two kinds of virulence genes were detected by PCR and underwent multi-locus sequence typing (MLST), Staphylococcus protein A (spa) typing and staphylococcal chromosome cassette (staphylococcal cassette chromosome mec, SCCmec) typing characterizing methicillin-resistant Staphylococcus aureus (MRSA). Statistical analysis was performed using χ 2 test or Fisher exact test. Results:MRSA isolates accounted for 50.94% of the total(27/53), with ST398-t034-SCCmecV (6/53, 11.32%) and ST59-t437-SCCmecIV (4/53, 7.55%) as the most common MRSA clones. Methicillin-sensitive Staphylococcus aureus (MSSA) isolates occupied 49.06% (26/53), among which typing ST22-t309 (3/53, 5.66%) and ST7-t091/t1685 (2/53, 3.77% each) were prevalent. Of the 53 strains, all carried ≥6 virulence genes, 33 strains (62.26%) carried ≥10 virulence genes, including 18 strains of MSSA (69.23%) and 15 strains of MRSA (55.56%). The carriage rate of pvl gene in MSSA was higher than that of MRSA isolates (12/26, 33.33% vs. 6/27, 22.22%), and sasX was only detected in MRSA isolates (4/53, 7.55%). The resistant rates of BSI-SA isolates to penicillin, erythromycin and clindamycin were 98.11%, 49.06% and 41.51%, respectively. MRSA were more resistant to clinical antimicrobial agents than MSSA. Conclusions:MRSA strains cover a high proportion in S. aureus bloodstream infection of children, with ST398-t034 and ST59-t437 being the most common clones. The virulence gene carrying rate for BSI-SA was high with a greater pvl gene carrying rate in MSSA isolates while sasX was only detected in MRSA isolates. More clinical attention should be paid to the high resistance status and virulence genes characteristics of BSI-SA.
ABSTRACT
OBJECTIVE:To study the interaction of baicalin with berberine for intestinal absorption in rats. METHODS: The mode was induced by in situ intestinal perfusion to observe the absorptive kinetics characteristic in rats’ intestine before and after mixing. RESULTS: The absorption rate constant (ka) and absorption rate (A) of baicalin alone were (0.068?0.002)h-1 and (5.92?1.39)% while those of baicalin mixed with berberine were (0.060?0.002)h-1 and (4.27?1.23)% , respectively. ka and A of berberine alone were (0.044?0.003)h-1 and (3.47?0.64)% while those of berberine mixed with baicalin were (0.057?0.006) h-1 and (5.18?0.83)%, respectively. There were significant difference in the absorption rate constant of baicalin after mixing(P