Lin Yuan

Capital Medical University, Peping, Beijing, China

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Publications (4)7.19 Total impact

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    ABSTRACT: To evaluate the epidemiology and molecular features of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and methicillin-sensitive S. aureus (MSSA) from children with skin and soft tissue infections (SSTIs) in Beijing, China, prospective community-acquired S. aureus SSTIs surveillance was conducted at the Beijing Children's Hospital, Beijing, China, for a 12-month period from August 1, 2008, to July 30, 2009. Susceptibility to 12 antimicrobials was determined by the agar dilution method. Genotypic characteristics of CA-MRSA isolates were tested by SCCmec typing, spa typing, and multilocus sequence typing. Panton-Valentine leukocidin gene was detected. Of 1104 cases, 31.8% (351) were community-acquired S. aureus. CA-MRSA accounted for 4% (14) of S. aureus. Among 14 CA-MRSA and 120 MSSA isolates tested, 100% and 91.7% were multidrug resistant, respectively. ST59-MRSA-IVa-t437 (42.9%) was the most common form of CA-MRSA. Spa typing analysis of 120 MSSA isolates was performed, followed by pulsed-field gel electrophoresis and multilocus sequence typing of a selected number of isolates. The most common spa types among MSSA were t084 (8.3%), t091 (5.8%), t034 (5%), t127 (4.2%), t002 (4.2%), and t796 (4.2%). No predominant spa type was seen. Of the MSSA isolates that could be classified into spa-CCs, 15.0% had a genetic background observed in CA-MRSA clones (spa-CC437, spa-CC342, and spa-CC377). Panton-Valentine Leukocidin (PVL)-positive community-acquired S. aureus strains were more commonly associated with skin abscesses than other SSTIs (29.4% versus 5.9%, P < 0.01).In conclusion, CA-MRSA infections are not common among Chinese children with SSTIs. Our findings show that MSSA strains in China have diverse genetic backgrounds.
    Diagnostic microbiology and infectious disease 03/2010; 67(1):1-8. · 2.45 Impact Factor
  • International Journal of Infectious Diseases - INT J INFECT DIS. 01/2009; 13.
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    ABSTRACT: To investigate the nasopharyngeal carriage and antimicrobial susceptibility of H. influenzae among children younger than 5 years old and to assess antibiotics usage patterns in the outpatient department of Beijing Children's Hospital from 2000 to 2004. From 2000 to 2004, At least 100 strains of H. influenzae were isolated from the pediatric patients who were younger than 5 years and who presented with symptoms of acute upper respiratory tract infections during February to May in each of the study years. Antimicrobial susceptibilities were determined; and antibiotics usage was expressed as defined daily dose (DDD)/100 patient days. The overall nasopharyngeal carriage rate of H. influenzae is 26.3% (562/2,137) in children younger than 5 years old with acute upper respiratory tract infection. The percentage of ampicillin-resistant isolates ranges from 4.0% (4/100) to 14.3% (17/119) from 2000 to 2004. All the ampicillin-resistant isolates are beta-lactamase producers. More than 80% of the isolates are susceptible to amoxicillin, cefaclor, and chloramphenicol; whereas, almost all (99-100%) of the isolates are sensitive to amoxicillin/clavulanic acid, ceftriaxone, and cefuroxime. For antibiotics utilization, macrolides are the predominantly used antibiotics, followed by cephalosporins and penicillins among pediatric patients in the outpatient department during the study period. All amoxicillin-resistant isolates of H. influenzae are producing beta-Lactamase; and the rates of amoxicillin-resistant isolates are increasing over time. Amoxicillin/clavulanic acid and cephalosporins are highly sensitive to H. influenzae isolated from Chinese pediatric patients. Macrolides are the most used antibiotics in the outpatient department during the study period.
    Pediatric Pulmonology 06/2008; 43(5):457-62. · 2.38 Impact Factor
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    ABSTRACT: This study investigated macrolide-resistant Streptococcus pneumoniae carried by Beijing children presenting with respiratory tract infections. Nasopharyngeal S. pneumoniae strains were tested for sensitivity with 15 antibiotics and further analyzed for phenotypes of macrolide-resistant strains and by PCR for the macrolide-resistant genes ermB, mefA, tetM, and integrase of conjugative transposon (Tn1545) intTn. We found 185 strains of S. pneumoniae relatively highly resistant to erythromycin (78.9%), clindamycin (76.2%), tetracycline (86%), and SMZ-TMP (78.7%) but with relatively low resistance to amoxicillin (2.2%), cefaclor (15.5%), ceftriaxone (2.8%), and cefuroxime (14.1%). The 146 strains of erythromycin-resistant S. pneumoniae showed extensive cross-resistance to other macrolides like azithromycin (100%), clarithromycin (100%), acetylspiramycin (95.2%), and clindamycin (95.9%). Genes ermB and mefA were detected in all erythromycin-resistant strains, with ermB(+) 79.5%, ermB + mefA(+) 17.8%, and mefA(+) 2.7%. About 96.9% of tetracycline-resistant isolates were positive for tetM, compared to 26.9% of sensitive strains. Ninety percent of tetracycline-resistant strains were also erythromycin-resistant versus 11.5% of tetracycline-sensitive strains. The intTn gene was present in 87.6% of S. pneumoniae strains and correlated with erythromycin and tetracycline resistance. The close relationship between the conjugative transposon Tn1545 and the genes ermB and tetM is probably one of the important mechanisms explaining the multiple drug resistance of S. pneumoniae.
    Microbial Drug Resistance 02/2008; 14(2):155-61. · 2.36 Impact Factor