Analysis Of The Clinical Status Of Mycobacterium Abscessus Pulmonary Disease And Factors Affecting The Effects Of Anti-infection Treatments

Objective:To analysis the clinical characteristics of mycobacterium abscessus complex（MABC）pulmonary disease and factors affecting the outcomes of treatment of MABC pulmonary disease from the aspects of hosts,therapeutic measures and bacteria.Methods:Information of patients with confirmed MABC and other non-tuberculous mycobacterium（NTM）pulmonary diseases who entered Shanghai pulmonary hospital from January 2012 to December 2017 was collected,screened,sorted and analyzed for trends in MABC pulmonary disease over years and clinical characteristics and therapeutic effects of MABC pulmonary disease as a whole or in relation to subspecies typing.Besides,MABC strains still preserved in the hospital laboratory were cultured,with antimicrobial susceptibility tests and whole genome sequencing performed in order to obtain information on bacterial colony morphology,drug resistant spectrum,genes responsible for clarithromycin resistance and so on.Survival analysis was performed and COX proportional hazard models were established to determine the clinically significant factors affecting treatment of MABC pulmonary diseaseResults:1)Trends in MABC pulmonary disease:A total of 1583 cases of NTM pulmonary diseases were retrieved,including 649 males,accounting for 41.0%,and934 females,accounting for 59.0%.The lowest and highest age among these subjects was 17 and 89 years old,respectively,with the median age of 53 years old.There were 957 cases（76.6%）who were older than 45 years old and 697 cases（43.9%）who were older than 60 years old,with the peak ages between 46 and 60 years old.Among the 1583 cases of NTM pulmonary diseases,505 subjects were infected with MABC,which accounted for 31.9%.During the period between 2012 and 2017,the absolute numbers of patients diagnosed with MABC pulmonary disease were 77,56,75,100,93 and 104 for each year,which accounted for 29.8%,28.3%,30.2%,32.9%,32.6%and 35.9%of total cases of NTM pulmonary diseases each year,respectively.A gradual increasing trend was observed using a chi-square test for trends,although it failed to reach statistical significance（P=0.061）.2)Host factors affecting therapeutic effects of MABC pulmonary disease:Compared with subjects infected by other NTM pulmonary diseases,more patients with MABC pulmonary disease were female（73.0%vs 57.2%,P<0.001）and suffered heamoptosis（24.2%vs 17.2%,P=0.032）.In contrast,more patients with other NTM pulmonary diseases had a history of tuberculosis or NTM infection（61.3%vs 52.0%,P=0.022）,had comorbid chronic obstructive pulmonary disease or asthma（26.1%vs 10.7%,P<0.001）,were using corticosteroids（10.6%vs 5.7%,P=0.033）and bronchodilators（13.9%vs 8.6%,P=0.044）.Except variables talked above,patients with MABC pulmonary disease demonstrated no differences in demography,symptom,medical history,comorbidities,radiological characteristics,pulmonary function and laboratory examinations compared with patients with other NTM pulmonary disease（P>0.05）,but suffered significantly lower rates of treatment success（45.1%vs 54.7%,P=0.018）and symptom improvement（56.1%vs66.8%,P=0.007）.Compared with those infected by Mycobacterium abscessus subsp.massiliense（M.massiliense）,more patients with Mycobacterium abscessus subsp.abscessus（M.abscessus）demonstrated fibro-cavitary type on chest imaging（30.8%vs 6.8%,P<0.001）,and the rates of treatment success（33.5%vs 81.4%,P<0.001）and improvement in symptom（47.0%vs 84.7%,P<0.001）and imaging manifestations（35.1%vs 64.4%,P<0.001）were significantly lower in patients with M.abscessus pulmonary disease than in those with M.massiliense pulmonary disease.Survival analysis and COX proportional hazard analysis indicated BMI,use of corticosteroids,imaging type are significant host factors.3)Therapeutic factors affecting therapeutic effects of MABC pulmonary disease:Among all the MABC pulmonary disease patients,the frequency of amikacin,imipenem,linezolid and tigecyline application were 94.5%,35.5%,21.8%and 29.1%in patients with treatment success,which were significantly higher than 85.1%,20.9%,10.4%and 15.7%,respectively,in patients with treatment failure（P=0.017,0.011,0.015 and 0.011 respectively）.Among the M.abscessus pulmonary disease patients,the frequency of amikacin,imipenem,linezolid and tigecyline application were 37.1%,96.8%,35.5%,24.2%and 30.6%in patients with treatment success,which were significantly higher than 19.5%,86.2%,20.3%,9.8%and 16.3%,respectively,in patients with treatment failure（P=0.010,0.025,0.025,0.009,0.024 respectively）.In contrast,the use of clarithromycin were significantly lower in patients with treatment success than in those with treatment failure（71.0%vs 85.4%,P=0.020）.All these differences were not detected among patients with M.massiliense pulmonary disease（all P>0.05）.A total of 319 adverse events and 60 severe adverse events were documented.Most adverse events caused mild symptoms that could be well tolerated by those patients.None of these events resulted in disabilities or deaths.Among the244 patients who were treated successfully,the percentage of patients who underwent at least one severe adverse events were 18.2%,which was significantly lower than in those of 29.9%with treatment failure（P=0.035）.In patients with M.abscessus pulmonary disease,the percentage of patients who underwent at least one severe adverse events were 14.5%,which was significantly lower than 31.7%in those with threatment failure（P=0.012）.Similarly,in patients with M.massiliense pulmonary disease,the percentage of patients who underwent at least one severe adverse events were 12.5%,which was significantly lower than 54.5%in those with treatment failure（P=0.006）.Results from survival analysis and COX proportional hazard models indicated that among the 244 MABC pulmonary disease patients,use of azithromycin rather than clarithromycin,amikacin,linezolid adverse events and severe adverse events were significantly associated with treatment success（P=0.018,0.020,0.021,0.017,0.036 and 0.001）,even after adjustment for confounding factors including BMI,use of corticosteroids,imaging manifestation and MABC subspecies.Among patients with M.abscessus pulmonary disease,use of azithromycin rather than clarithromycin,imipenem,linezolid,tigecycline,duration of intravenous injection,number of adjustment for therapeutic regimens,severe adverse events significantly influenced the effects of treatment（P=0.002,0.031,0.005,0.001,0.004,0.028 and 0.008,respectively）,while in subjects with M.massiliense pulmonary disease,no such factors were identified as important（all P>0.05）.4)Bacterial factors affecting therapeutic effects of MABC pulmonary disease:Among the 194 MABC preserved in the hospital laboratory,there were 126（64.9%）,15（7.7%）and 53（27.3%）isolates forming rough,smooth and mixed colonies,respectively,while 25（12.9%）and 169（87.1%）isolates carried wild type and mutant glycopeptidolipid（GPL）genes,respectively.The distribute patterns of colony phenotypes and GPL genotypes were not significantly different between M.abscessus and M.massiliense isolates（P=0.199）.Among the subjects infected by the 194isolates,there were 50（58.8%）,10（11.8%）and 25（29.4%）patents infected by isolates forming rough,smooth and mixed colonies,respectively,in those with treatment success,while there were 76（69.7%）,5（4.6%）and 28（25.7%）patents infected by isolates forming rough,smooth and mixed colonies,respectively,in those with treatment failure,and no significant difference could be observed（P=0.117）.Neither did among M.abscessus and M.massiliense pulmonary disease patients separately（P=0.306 and 0.591,respectively）.Among the subjects infected by the 194isolates,there were 18（21.2%）and 67（78.8%）patents infected by isolates carrying wild type and mutant GPL genes in those with treatment success,while there were 7（6.4%）and 102（93.6%）patients infected by isolates carrying wild type and mutant GPL genes in those with treatment failure,with the difference reaching statistical significance（P=0.002）.Similar findings were also observed among patients with M.abscessus pulmonary disease（P=0.007）,but not in patients with M.massiliense pulmonary disease（P=0.476）.Data from survival analysis and COX proportional hazard models suggested that both colony phenotype and GPL genotype were not significantly associated with treatment success,after adjustment for confounding factors including BMI,use of corticosteroids,imaging manifestation and MABC subspecies（all P>0.05）.The proportion of multi-drug resistant isolates were 22.3%among M.abscessus,which was significantly higher than 6.5%in M.massiliense（P=0.017）.Among the subjects infected by the 194 isolates,there were 20（23.5%）,32（37.6%）,24（28.2%）and 9（10.6%）patients infected by isolates resistant to 0,1,2 and3-4 first-line antibiotics,respectively,in those with treatment success,while there were 12（11.0%）,41（37.6%）,29（26.6%）and 27（24.8%）patents infected by isolates resistant to 0,1,2 and 3-4 first-line antibiotics,respectively,in those with treatment failure,with the difference reaching statistical significance（P=0.021）.No such differences were identified among patients with M.abscessus and M.massiliense pulmonary disease（P=0.234 and 0.345,respectively）.Data from survival analysis and COX proportional hazard models suggested that multi-drug resistance were clinically significant factors affecting MABC pulmonary disease treatment,even after adjustment for confounding factors including BMI,use of corticosteroids,imaging manifestation and MABC subspecies（P=0.012）.The MIC₅₀ and MIC₉₀ of 194 isolates against clofazimine were 0.5μg/ml and 1.0μg/ml,respectively,which were 0.125μg/ml and 0.25μg/ml,respectively,for Bedaquiline.There were no significant differences in the susceptibility against clofazimine and bedaquiline between multidrug resistant MABC and other isolates.Among the 32 MABC isolates tested in this study,the lowest MIC against rimonabant reached up to 4μg/ml,with most MICs higher than 32μg/ml.The value of MIC₅₀ and MIC₉₀ against rimonabant were both 64μg/ml,indicating no anti-MABC activity.The positive predictive value,negative predictive value,and accuracy of genotyping based upon genes related to clarithromycin resistance to predict clarithromycin resistance were 96.1%,87.7%and93.3%,respectively,with the value of Kappa equaling to 0.848（P<0.001）.The positive predictive value,negative predictive value,and accuracy of genotyping based upon MABC subspecies to predict clarithromycin resistance were 85.8%,89.1%and86.6%,respectively,with the value of Kappa equaling to 0.669（P<0.001）.Data from survival analysis and COX proportional hazard models suggested that clarithromycin resistance genotype was important factors affecting treatment of MABC pulmonary disease even after adjustment for confounding factors including BMI,use of corticosteroids,imaging manifestation（P=0.004）,and thus could be used instead of MABC subspecies.Conclusion:1)MABC remained one of the dominant strains causing NTM pulmonary diseases in Shanghai and the surrounding area,with a trend in the prevalence of MABC pulmonary disease increasing gradually year by year.2)Compared with subjects infected by other NTM pulmonary diseases,more patients with MABC pulmonary disease were female,suffered heamoptosis and demonstrated higher rates of erythrocyte sedimentation.The percentage of treatment success,improvement of symptom were significantly lower in patients with MABC pulmonary disease than in those with other NTM pulmonary disease.Compared with those infected by M.massiliense,more patients with M.abscessus demonstrated fibro-cavitary type on chest imaging,and the rates of treatment success and improvement in symptom and imaging manifestations were significantly lower in patients with M.abscessus pulmonary disease than in those with M.massiliense pulmonary disease.3)Emaciation,long-term use of corticosteroids,fibro-cavitary type on chest imaging are significant host factors affecting treatment of MABC pulmonary disease.Incorporation of azithromycin,rather than clarithromycin,amikacin,imipenem,linezolid,or tigecycline into the multi-drug regimens based on microlides could augment the chance of achieving treatment success.But caution should be paid to the adverse events related to antibiotics.In addition,the duration of parenteral injection should be extended to at least 4 weeks and,if conditions permitted,at least three kinds of parenteral antibiotics were preferred for patients infected with M.abscessus.4)Isolates forming rough/mixed colonies or those carrying mutant GPL genes could exert adverse influence on the therapeutic effects of MABC pulmonary disease probably through pathways including chronic consumption and pulmonary cavitation.5)Compared with M.massiliense,M.abscessus isolates were more likely to develop into multi-drug resistant MABC strains,which resulted in infections more refractory to treatment.Clofazimine and bedaquiline showed potent anti-MABC（including multi-drug resistant isolates）activity in vitro,and thus could become one of the therapeutic options of MABC infection treatment.However,rimonabant failed to show any anti-MABC activity.6)Detection of the genotype related to clarithromycin resistance（mutant rrl and erm（41）of T28 sequevar）appeared preferable to MABC subspecies in early predicting clarithromycin resistance accurately and later guiding treatment decision.In view of the poor prognosis of infection by isolates carrying clarithromycin resistant genes,clarithromycin resistance genotype could be used instead of MABC subspecies to predict poor treatment outcomes of MABC pulmonary disease.