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Objective To investigate the species and drug resistance of pathogens causing bloodstream infections in hospitalized patients,and provide scientific evidence for antimicrobial use and control of healthcare-associated blood-stream infection.Methods From January 1 to December 31,2012,16 428 blood specimens were performed blood culture,pathogens were isolated and performed antimicrobial susceptibility testing.Results Of 16 428 blood speci-mens from 5 546 patients,384 (6.92%)were positive for blood culture,398 pathogenic isolates were detected,of which gram-positive bacteria,gram-negative bacteria,and fungi accounted for 23.62% (n=94),68.34% (n=272),and 8.04% (n=32)respectively,positive rate of blood culture were highest in 61-80 age group(8.26%), the top five departments of positive rate of blood culture were departments of burn,traditional Chinese medicine, cardiac intensive care unit,transplantation and traumatology;gram-positive cocci were highly susceptible to vanco-mycin,teicoplanin and linezolid,one Enterococcus faecium strain was found to be resistant to vancomycin;Among gram-negative bacilli,Enterobacteriaceae were highly susceptible to amikacin and carbapenems;drug resistance rates of Acinetobacterbaumannii and Pseudomonasaeruginosa to carbapenems was 70.97% and 35.90% respective-ly.Conclusion Gram-negative bacteria are the major pathogens causing bloodstream infection,positive rate of blood culture of elderly people is high.It is necessary to conduct regular surveillance on distribution and drug resistance of pathogens.
RESUMO
Objective To evaluate the practicability of CHROMagar orientation medium combined with simple biochemical tests for identification of common oxidase-negtive gram-negative bacilli.Methods The CHROMagar orientation medium was used together with biochemical tests including indole test , ornithine decarboxylase test and lysine decarboxylase test for identification of common oxidase -negtive gram-negative bacilli.The sensitivity, specificity, likelihood ratio, Youden index and Kappa value of the diagnostic assays were evaluated .McNemar test was performed to evaluate facticity, accuracy and cost of the method in com-parison with the Vitek-2 system as reference method .Results The identification of oxidase-negtive gram-negative bacilli from 318 bacterial strains showed that the sensitivities and specificities of CHROMagar orien-tation mediumm in combination with simple biochemical tests to Serratia marcescens, Stenotrophomonas mal-tophilia and Acinetobacter baumannii reached 100%, and for Escherichia coli, Enterobacter aerogenes and Klebsiella pneumoiae were above 90%.The specificities for identification of Enterobacter cloacae, Klebsiella oxytoca, Citrobacter freundii and Proteus mirabilis were all above 90%, but the sensitivities were around 75%-90%.Kappa values of the assays were above 0.85, howerer, which was only 0.5947 for Citrobacter freundii.McNemar test showed that all P values were above 0.05, and cost of the assays was reduced by 90%.Conclusion CHROMagar orientation medium in combination with simple biochemical tests is a cost-effective assay for identification of common oxidase-negtive gram-negative bacilli .