Objective To investigate the effects of photodynamic therapy (PDT) on Staphylococcus aureus and Escherichia coli strains and their laboratory-developed biofilms in vetro and the basic mechanisms of its action.Metods The bacteria were irradiated with a He-Ne laser in the presence of toluidine blue O (TBO).The colony forming units (CFU) of each strain were countde before and after treatment,and the uptakd of TBO by the bacteria was determined using fluorospectrophotometry. Results With a constant light dose,the bactericidal effects of PDT against the two bacteria cultures increasde woth the concentration of TBO,with the strongest bactericidal effect after PDT treatment more than 90%.S.aureus seemed to be more sensitive to PDT than E.coli,though the amount of TBO absorbed by the E.coli cells was significantly larger.The effects of PDT on mature and immature biofilms formed by the two strains showed no significant difference.The bactericidal rate was 20% to 30%.Conclusion Ge-Ne laser irradiation associated with TBO demonstrated significcant photodynamic bactericidal effects on S.arueus and E.coli strains cultivatde in vitro,but the iffects on their biofilms wer limitde.The efficacy of PDT was independent of the absorption of TBO into the bacterial cells.

Objective To study the iodine nutritional status of pregnant women in Foshan City,Guangdong Province,and to provide basis for iodine supplementation scientifically for them.Methods In 2017,five districts Chancheng,Nanhai,Shunde,Sanshui and Gaoming in Foshan were selected.Each monitoring site was divided into five sections according to stratified random sampling in five directions:east,west,south,north and middle.One township (street) was taken in each section,and 20 pregnant women were taken from each township (street) to detected their family salt iodine and urinary iodine levels.Results A total of 500 edible salt samples were collected from the families of pregnant women,the median of salt iodine was 24.8 mg/kg,the qualified iodized salt consumption rate was 95.8％ (479/500),and the iodized salt coverage rate was 99.0％ (495/500).There was a statistically significant difference in the iodine content of edible salt of pregnant women in diffierent districts (H =26.9,P ＜ 0.05).A total of 500 urine samples were collected from pregnant women,the median of urinary iodine was 138.9 μg/L.There was a statistically significant difference in the levels of urinary iodine content of pregnant women in different districts (H =14.5,P ＜ 0.05).There was no statistically significant difference in urinary iodine of pregnant women during different stages of pregnancy (H =2.6,P ＞ 0.05).Conclusions The iodine intake for pregnant women is in a state of deficiency (＜ 150 μg/L) in Foshan of Guangdong Province.It is necessary to further strengthen the health education of key populations,and improve the iodine nutritional status of pregnant women.