Analysis Of Clinical Characteristics,Drug Selection And Adverse Prognostic Factors Of Pulmonary Nocardiosis

Objective:(1)To investigate clinical characteristics and antibiotic selection of pulmonary nocardiosis.(2)To investigate the pathogenic effect of new Nocardia strains on pulmonary infection.(3)To analyze the poor prognostic factors of pulmonary nocardiosis.Methods:This was a retrospective study.Patients who were diagnosed as pulmonary nocardiosis in five hospitals in the past four years were investigated and followed up,including collecting these clinical data.The clinical features and risk factors for the poor prognosis of these patients were studied.Results:(1)A total of 32 cases of pulmonary nocardiosis were collected,including 12 cases of longterm use of glucocorticoid(GC)and/or immunosuppressive drug(ISD),9 cases of structural pulmonary disease,and 8 cases of diabetes.(2)The main symptoms included cough(100.00%),expectoration(100.00%).fever(81.25%).dyspnea(62.50%),hemoptysis(34.38%).(3)Most patients showed neutrophilia(71.88%)and lymphopenia(68.75%).The neutrophil-lymphocyte ratio(NLR)was higher than that of healthy people.(4)The pathology showed lung tissue hemorrhage,necrosis,suppurative granulomatous inflammation and granulation tissue hyperplasia.(5)The CT patterns included multiple nodules(81.25%),masses(65.63%)and cavities(62.50%)in both lungs,and protrusions could be seen on the walls of cavities.(6)25 cases of sputum culture were positive,and 1 case of pleural effusion culture positive.There were 12 cases submitted for mNGS and all of them were positive,including 10 cases of bronchoalveolar lavage fluid(BALF)and 2 cases of lung tissue.Among 12 cases with mNGS positive,pathogens were simultaneously identified in 6 cases with bacterial culture,while 6 cases were negative.The time of result for mNGS was earlier than the time of result for traditional culture.A total of 34 isolates were obtained,including 10 isolates of Nocardia otitidiscaviarum,5 isolates of Nocardia cyriacigeorgica,5 isolates of Nocardia farcinica,2 isolates of Nocardia Wallace,1 isolate of Nocardia pseudobrasiliensis,1 isolate of Nocardia amamiensis,1 isolate of Nocardia pneumoniae,1 isolate of Nocardia abscessus and 1 strain of Nocardia brasiliensis.and 7 isolates were identified as Nocardia but species could not be further determined.Antibiotic susceptibility rate was 100%for linezolid(LZD).88.89%for Trimethoprim-sulfamethoxazole(TMP-SMX),66.67%for levofloxacin(LEV),37.50%for imipenem(IMP)+meropenem(MPN),11.11%for ceftriaxone(CRO)and 0%for vancomycin(VA).The susceptibility of Nocardia otitidiscaviarum to IMP was only 16.67%.Nocardia pneumoniae is sensitive to LZD,SXT,MPN and CRO,and resistant to LEV and VA.(7)There were 14 cases of severe pneumonia.Compared with patients in the normal group,patients in the severe group had a higher proportion of diabetes,CS and(or)ISD and co-infection.Furthermore,patients in the severe group had a lower level of leukocytosis,and albumin.(8)11 cases recoverd,10 cases improved and 11 cases died.Compared with patients of the survival group,patients of the death group had a higher proportion and level of NLR,diabetes and coinfection.Furthermore,patients in the death group had a lower level of leukocytosis,oxygenation index and albumin.Logistic multivariate regression analysis showed that diabetes(OR=12.105,95%CI 1.210～121.080,p=0.034)and hypoalbuminemia(OR=0.780,95%CI 0.621～0.979,p=0.032)were independent risk factors for poor prognosis of pulmonary nocardiosis.Conclusion:(1)Long-term application of GC and(or)ISD,structural pulmonary disease and diabetes are the susceptible factors for pulmonary nocardiosis.(2)Pulmonary nocardiosis is characterized by fever,cough,multiple nodules in both lungs,masses,cavities and protrusions on cavities walls.(3)BALF mNGS is an efficient method to detect Nocardia.(4)The susceptibility of Nocardia to antibiotics varies among species.All Nocardia isolates were susceptible to linezolid,and 84%of Nocardia otitidiscaviarum were resistent to imipenem.(5)Nocardia amamiensis and Nocardia pneumoniae are new species causing penumonia.(6)Diabetes and hypoalbuminemia are independent risk factors for poor prognosis of pulmonary nocardiosis.