Objective To investigate the basic status of healthcare-associated infection(HAI)in a hospital,and provide evidence for strengthening HAI management.Methods A cross-sectional study was conducted to investi-gate the prevalence rates of HAI in all hospitalized patients at 0 ∶00 -24∶00 of May 7,2014.Results A total of 2 262 patients were supposed to be investigated,while 2 253 (99.60%)patients were actually investigated,586 of whom (26.01%)came from pulmonary hospital(specialized in tuberculosis)affiliated to the general hospital.53 patients devel-oped 58 times of HAI,prevalence rate and case prevalence rate was 2.35% and 2.57% respectively;1 073 patients devel-oped 1 265 times of community-acquired infection (CAI),prevalence rate and case prevalence rate was 47.63% and 56.15% respectively.Rates of HAI and CAI were high in intensive care unit(ICU,21.28%)and pulmonary hospital (99.49%)respectively;the main infection site was lower respiratory tract,which accounting for 46.55%(n =27)and 69.72%(n=882)respectively.The major pathogens causing HAI were gram-negative bacteria(n = 19),and the major pathogens causing CAI were Mycobacteria(n=141)and fungi (n=89).The rate of antimicrobial usage and etiological ex-amination was 34.80%(n=784 )and 81.48%(n=550 )respectively.Conclusion In order to prevent cross infection of tuberculosis and reduce the incidence of HAI,lower respiratory tract and ICU should be one of the key infection sites and departments of HAI surveillance,treatment and management of patients with tuberculosis should be stand-ardized,professional precaution of health care workers should be enhanced.

Objective To explore the causes of twisted or tailed DNA bands in agarose gels after electro-phoresis .Methods Prestained and poststained methods were employed to exam 3 kinds of DNA marker bands in agarose gel with GeneGreen and Ethidium Bromide ,respectively .Results Three kinds of DNA marker bands in agarose gel with 1:10000 and 1:5000 concentration of GeneGreen showed obvious distortions and trailing phenomena compared with the same concentration of Ethidium Bromide w hen the prestained method was used for electrophoresis ,which were improved when the poststained method was used in agarose gel with GeneGreen and Ethidium Bromide ,respectively .Conclusion Nucleic acid dye GeneGreen can affect the quali-ty of DNA bands in agarose gel electrophoresis .When the quality of DNA itself ,agarose gel quality ,electro-phoretic fluid quality and voltage are excluded ,the quality of nucleic acid dye should be taken into considera-tion if the bands twisting or tailing occurs when the DNA nucleic acid electrophoresis is carried out by pres-tained method .The quality of DNA electrophoresis bands can be improved by using poststained method or re-placing nucleic acid dye .