Genotypic Characterization of Methicillin-resistant Staphylococcus aureus Isolated from Pigs and Retail Foods in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the genotypic diversity of Methicillin-resistant Staphylococcus aureus (MRSA) isolated from pigs and retail foods from different geographical areas in China and further to study the routes and rates of transmission of this pathogen from animals to food.</p><p><b>METHODS</b>Seventy-one MRSA isolates were obtained from pigs and retail foods and then characterized by multi-locus sequencing typing (MLST), spa typing, multiple-locus variable number of tandem repeat analysis (MLVA), pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing.</p><p><b>RESULTS</b>All isolated MRSA exhibited multi-drug resistance (MDR). Greater diversity was found in food-associated MRSA (7 STs, 8 spa types, and 10 MLVA patterns) compared to pig-associated MRSA (3 STs, 1 spa type, and 6 MLVA patterns). PFGE patterns were more diverse for pig-associated MRSA than those of food-associated isolates (40 vs. 11 pulse types). Among the pig-associated isolates, CC9-ST9-t899-MC2236 was the most prevalent clone (96.4%), and CC9-ST9-t437-MC621 (20.0%) was the predominant clone among the food-associated isolates. The CC9-ST9 isolates showed significantly higher antimicrobial resistance than other clones. Interestingly, CC398-ST398-t034 clone was identified from both pig- and food-associated isolates. Of note, some community- and hospital-associated MRSA strains (t030, t172, t1244, and t4549) were also identified as food-associated isolates.</p><p><b>CONCLUSION</b>CC9-ST9-t899-MC2236-MDR was the most predominant clone in pigs, but significant genetic diversity was observed in food-associated MRSA. Our results demonstrate the great need for improved surveillance of MRSA in livestock and food and effective prevention strategies to limit MDR-MRSA infections in China.</p>

Enhancement of vitamin A combined vitamin D supplementation on immune response to Bacille Calmette-Guérin vaccine revaccinated in Chinese infants

OBJECTIVE@#To investigate whether there is an association between diameter of bacille Calmette-Guérin (BCG) scars and effect of purified protein derivative (PPD) reaction and to determine whether vitamin A (VA) combined vitamin D (VD) supplementation influences the immune response to BCG revaccinated in Chinese infants.@*METHODS@#A cross-section and 3-month community-randomised trial was conducted. A total of 5 629 infants at 3, 6 and 12 months of age in Junan County of China were examined for BCG scar formation. Then, 597 revaccinated infants were randomly assigned to supplementation (n=307) and control (n=290) groups. The supplementation group were daily assigned to 1 500 IU VA and 500 IU VD for 3 months. Then all infants were subjected to skin test with PPD.@*RESULTS@#The diameter of BCG scars was positively correlated with diameter of skin indurations of PPD (r=0.17, P<0.05) in the 5 629 infants. The rate of positive response to PPD was higher in the supplementation group than in the control group (96.1% versus 89.7%, P<0.05, prevalence ratio 1.07, 95% CI 1.02-1.12). The prevalence ratio of PPD response for the supplementation group compared with that for the control group was 1.07 (95% CI 1.01-1.13) for the males and 1.08 (95% CI 1.00-1.17) for the females. For the supplementation group, the males got larger tuberculin induration than the females [(0.73±0.21) cm versus (0.67±0.20) cm, P<0.05) after intervention.@*CONCLUSIONS@#The diameter of BCG scars was effectively correlated with PPD response, which indicates BCG scar formation may be an useful tool to evaluate the effect of tuberculosis prevention. VA combined VD supplementation may play an immuno-regulatory role in BCG revaccination. This may contribute to the prevention of childhood tuberculosis.

Prevalence of thyroid nodules and influencing factors among employees of a company in Qingdao / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of thyroid nodules and influencing factors among employees of a company in Qingdao.</p><p><b>METHODS</b>Through questionnaires, physical examination, thyroid ultrasonography and urinary iodine test, personal health information and examinations of thyroid nodules of 9612 serving and retired employees in a company in 2010 who had lived in Qingdao for more than 5 years were collected to investigate the prevalence of thyroid nodules and its influencing factors.</p><p><b>RESULTS</b>The prevalence of thyroid nodules was 36.56% (3514/9612). The prevalence rates of single nodules and multiple nodules were 18.39% (1768/9612) and 18.16% (1746/9612) respectively. With increasing urinary iodine level, the prevalence of multiple thyroid nodules decreased from 25.51% (366/14350)(urinary iodine < or = 100 microg/L) to 12.99% (214/1648) (urinary iodine > 300 microg/L) showing a clear downward trend (chi2 = 67.11, P < 0.01). The prevalence rates of thyroid nodules among males and females were 31.28% (2283/7299) and 53.22% (1231/2313) (P < 0.01) respectively. With increasing age, the prevalence of thyroid nodules gradually increased from 7.95% (67/843) (19 - 29 years old) to 58.81% (267/454) ( >70 years old) among males and increased from 23.74% (33/139) (19 - 29 years old) to 80.38% (127/158) ( >70 years old) among females. The prevalence of thyroid nodules among males and females showed an increasing trend with age (male: chi2 = 434.12, P < 0.01; female: chi2 = 40.74, P < 0.01). The results of logistic regression showed that compared with males, females were more susceptible to thyroid nodules (OR = 2.809, 95% CI: 2.444 - 3.228). Smoking (OR = 1.394, 95% CI: 1.249 - 1.556), hypertension (OR = 1.155, 95% CI: 1.040 - 1.282), diabetes ( OR = 1.228, 95% CI: 1.039 - 1.452) and overweight (OR = 1.199, 95% CI: 1.078 - 1.333) might be risk factors for thyroid nodules after adjusting for age and gender.</p><p><b>CONCLUSION</b>The prevalence of thyroid nodules was high among the employees. In order to reduce the thyroid nodules, smoking cessation and weight control should be promoted. Blood pressure and glucose level should be actively controlled for patients with hypertension and (or) diabetes.</p>

Effect of multiple micronutrients supplementation on anti-oxidative activity and oxidized DNA damage of lymphocytes in children / 中华流行病学杂志

<p><b>OBJECTIVE</b>To examine the effect of multiple micronutrients supplementation on anti-oxidative activity and decreasing oxidized DNA damage of lymphocytes in Chinese children.</p><p><b>METHODS</b>82 healthy children in a rural areas, aged 9-11 years, were selected and randomized allocated into group receiving supplements and control group with each of them 41. 24-hour dietary recall was used to collect data on daily nutrient intakes of the research subjects. The subjects in the supplement group were given vitamin A (VA) 600 microg, beta-carotene (beta-C) 1.0 mg, vitamin E (VE) 100 mg, vitamin C (VC) 300 mg and Na2SeO3(Se) 200 microg in a tablet on daily base while those in the control group took a same-sized color placebo tablet. The trial lasted 8 weeks. 5 ml blood samples from each subject were taken during 7 to 9 o'clock in the morning. DNA damage of lymphocytes and levels of plasma VA, VE, VC, beta-C, Se, malondialdehyde (MDA), activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were then analyzed twice before and after the 8-week of trial.</p><p><b>RESULTS</b>The low intakes of VA, VC and Se only accounted for 50.6%, 65.6% and 67.3% of their recommended nutrient intake (RNI) respectively. After the trial, levels of plasma beta-C, VA, VE, VC and Se in the supplemented group increased by 13.4%, 32.8%, 11.5%, 46.9% and 24.6% respectively, compared with the control group, indicating that nutritional status regarding antioxidant nutrients had largely been improved. GSH-Px activity had a significant increase in the supplement group than before the supplement and in the control group (P < 0.01). GSH-Px before the trial (the 100.4 U/ml) also showed significant increase after the trial (161.7 U/ml) (P < 0.01). However, the values of SOD and MDA significantly decreased after the trial. Analysis of DNA damage indicated that there was no significant difference in the intrinsic damage of DNA (P > 0.05). Significant decreases of oxidized DNA damage induced by 5 micromol/L, 10 micromol/L and 25 micromol/L H2O2 were found more in peripheral lymphocytes of the supplemented group, than in pre-supplement and the control group after the trial (P < 0.01).</p><p><b>CONCLUSION</b>Supplementation of multiple micronutrients could effectively increase the levels of beta-C, VA, VE, VC and Se in plasma, and GSH-Px activity. In the meantime, MDA and oxidized DNA damage induced by a low level H2O2 decreased significantly after the trial. The reason accounted for the decrease of SOD activity after the trial needs to be further studied.</p>