Molecular characteristics of methicillin resistant Staphylococcus aureus isolated from Chinese children / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Chinese children in seven cities.</p><p><b>METHOD</b>A total of 134 MRSA isolates were collected from nine hospitals. Multilocus sequence typing and spa typing were analyzed by polymerase chain reaction (PCR), and staphylococcal chromosomal cassette mec (SCCmec) type was analyzed by multiplex PCR. The Panton-Valentine leukocidin (pvl) gene was also detected.</p><p><b>RESULT</b>Most MRSA strains were isolated from pneumonia and skin and soft tissue infection (SSTIs) patients, accounting for 82.1%. Overall, 16 sequence types (STs) were obtained, and CC59 (51.7%) was found to be the most prevalent, which included ST 59 and ST 338, followed by ST239 (16.4%). SCCmec types II, III, IV, and V were also identified in the current study. SCCmec type IV was the most predominant type at 50.0%, followed by SCCmec type V at 23.9% and III at 23.9%. SCCmec subtypes IVa, IVc, and IVg were found among SCCmec type IV strains, whereas IVa was the main subtype at 77.6%. Twenty-six spa types were also identified, among which the predominant type was t437 (47.8%). The prevalence of pvl genes and the SCCmec type of strain was relevant, and the pvl gene positive rate was higher in SCCmec type IV and V-type strains than in SCCmec type II and III strains (58.6% vs. 14.3%, P < 0.05); there was a significant difference between them. In the strains isolated from pneumonia and SSTIs, ST59-MRSA-IVa(t437) was the predominant clone. There were five clones detected from the strains isolated from septicemia, with ST59-MRSA-IVa(t437) and ST59-MRSA-V(t437) as the main clones (57.1%). Various predominant clones existed in different regions. ST59-MRSA-IVa(t437) was the prevalent clone in the Guangzhou, Beijing, Chongqing, and Shenzhen areas, whereas ST239-MRSA-III(t037) was the prevalent clone in the Shanghai area. Fifty percent of the isolates from the Wenzhou area belonged to ST910-MRSA-V(t318), whereas three clinical strains isolated from the Shenyang region belonged to three different types.</p><p><b>CONCLUSION</b>The results indicate that MRSA isolates from Chinese children are largely associated with the ST59-MRSA-IV(t437) and ST239-MRSA-III(t037) clones. These two may belong to community-acquired MRSA and hospital-acquired ones, respectively. Different prevalent clones were detected in different diseases and different regions. Therefore, there is a need to conduct further research on clinical isolates, which can guide the choice of antibiotic treatment and the examination of MRSA prevalence.</p>

Influence of visual attention in visual evoked potential examination / 法医学杂志

OBJECTIVE@#To explore the influence of visual attention in visual evoked potential (VEP) examination.@*METHODS@#The pattern visual evoked potential (PVEP) and flash visual evoked potential (FVEP) were used to examine 110 normal subjects whose visual acuity or corrected visual acuity is in the range of 4.8-5.2, and age between 20 to 30 years old. In PVEP inspection, subjects were asked to watch with three ways, to stare at the central screen (at the same time count silently the number of alternating of black and white squares to improve the subjects' attention), to stare at the central screen at the same time thinking other things, to look sideways (the left eye stared at the left bottom corner of the screen or the right eye stared at the right one). In FVEP inspection, subjects were checked with eyes open and closed respectively. The latency and amplitude of P100 wave were recorded. The data were statistically analyzed by SPSS 13.0 software. RESULTS In PVEP inspection, the latency and amplitude of P100 wave were statistically different among three watching ways. In FVEP inspection, latency and amplitude of P100 wave were statistically different between eyes open and closed group.@*CONCLUSION@#Although the visual evoked potential test is an objective electrophysiological visual function test, it is susceptible to the influence of various subjective factors such as visual attention. It should arise the attention of forensic experts.