A Retrospective Study Of Infection In Patients With Systemic Lupus Erythematosus And Dermatomyositis

Background:Infection is one of the most common complications which is responsible for the morbidity and mortality in paitents with systemic lupus erythematosus(SLE) and dermatomyositis(DM).There used to be many clinical studies on infections with SLE,but researches are fewer in these years.And large-scale investigations on DM are even much fewer.Objective:To investigate infectious complications and analyse their risk factors in patients with SLE and DM,and give a clue for antibiotics treatment.Methods:533 cases of SLE and 307 cases of DM admitted to our hospital between 2002 and 2007 were reviewed,and the characteristics of their infections including the infection sites,pathogens and the tolerance of pathogenic bacteriawere investigated.The suspected risk factors of infections in patients with SLE and DM were selected and then analyzed by chi-square test and Logistic regression.Results:Incidence of infection was 24.4%in patients with SLE and 35.2% in patients with DM.16 cases of death were related to respiratory infections.The common infection sites were respiratory,urinary tract, skin and oral cavity in order.Bacteria were the most common pathogens of infections in SLE and DM patients,the majority pathogens were gram-negtive bacteria.The second major pathogens were fungus,and the third,the combination of bacteria and fungus.The common strains causing infections in SLE patients were Escherichia coli,Klebsiella pnoumonea, Pseudomonas aeruginosa,Staphylococcus aureus and Candida albus and in DM patients,Klebsiella spp.,Acinetobacter,Staphylococcus aureus and Candida albus.There were also seven SLE patients with tuberculosis and 10 with herpes zoster.Antimicrobial susceptibility tests showed a high proportion of drug resistant bacteria.There were 11ESBLs-producing strains and 10 strains of MRSA.The gram-negative ones were sensitive to cefoperazone-sulbactam and carbopenems.The infection-related risk analysis suggested that the independent risk factors of infections in SLE patients include elder age,hypoproteinemia,moderate anemia and high doses of corticosteroids treatment,and those of infections in DM patients included elder age,interstitial lung diseases,dysphagia and high doses of corticosteroids treatment.Conclusion:Those patients with infection-related risk factors should be monitored closely for infections.Respiratory tracts are the most common infectious sites in SLE and DM patients,and the infections in DM patients always lead to unfavouable prognoses;the main bacteria are gram-negtive ones,so such antibiotics as cefoperazone-sulbactam or carbopenems can be good choices before we get the result of antimicrobial susceptibility test.