Amplifying Drug Resistance And Associated Factors During Non-multidrug Resistant Tuberculosis Treatment:A Retrospective Study

Background:Microbial drug resistance(DR)has become a major public health concern worldwide.Due to endless international efforts to combat tuberculosis(TB),both the global mortality rate and incidence rate have decreased over the past 2 decades.Since the outbreaks of multidrug-resistant tuberculosis(MDR-TB)in the 1990s,it has grown to an estimated 480,000 cases and 210,000 deaths per year by 2015.It was estimated that the rate of treatment success for MDR TB patients was only 48%.One factor limiting successful therapy is the appearance of MDR-TB during treatment for non-multidrug-resistant tuberculosis(non-MDR-TB).With catastrophic cost,poor adherence,prollonged treatment duration and inadequate effective drugs.MDR TB has been associated with worse treatment outcomes than drug-susceptible TB.The serious amplifying drug resistance leads to extensively drug-resistant(XDR)and also increases the rate of treatment failure and causes enormous social and economic disruption.This retrospective study of non-MDR TB patients over an 8-year period was conducted to determine the prevalence of acquired drug resistance developed from non-MDR TB patients and evaluate factors associated with an increased risk for acquisition of DR TB among these patients,to compare the treatment outcomes between acquired DR group and drug susceptibility testing(DST)unchanged group.Thus physicians can take actions in preventing the occurrence of amplifying DR.It can also provide effective intervention strategies for the prevention and control of TB.Methods:We retrospectively analyzed the clinical and DST data of culture confirmed MDR TB cases treated in Shandong Provincial Chest Hospital from January 2007 to December 2014.All analyses were performed using SPSS,version 16.0.Data are presented as mean(±SD),numbers,or proportion.The Pearson X2 statistics was used to test the differences in prevalence.The general linear model(F-test)was used to compare means.To recognize independent factors associated with acquisition of resistance,multivariate logistic regression analysis is used.Results:1.Among 258 baseline non-MDR TB patients,38(14.7%)developed MDR,and 19(14.7%)developed XDR during treatment.Meanwhile,10(5.1%)of 198 baseline pan-sensitive TB patients acquired mono-DR,12(5.3%)in 228 baseline pan-sensitive and mono-DR TB patients acquired poly-DR.2.Prevalence of acquired DR were higher among baseline poly-DR TB(23/30,76.7%;P<0.001)and mono-DR TB patients(19/30,63.3%;P<0.001)than baseline pan-sensitive TB patients(56/198.28.3%).3.Smoking history(OR,1.74;95%CI,1.04-2.91),TB contact history(OR,3.91;95%Cl,1.23-12.44).cavity lesions(OR,2.26;95%CI,1.43-3.55)and repeated hospitalization(OR.2.34;95%CI,1.46-3.75)were independent risk factors for the acquisition of additional drug resistance TB.4.Compared with 60%favorable outcomes achieved in patients with unchanged DST results,only 39.8%of those who acquired DR-TB were cured or completed treatment(p<0.005).Among those whose DST unchanged TB patients,37(23.1%)lose to follow-up(LFU),11(6.9%)died,and 16(10%)failed treatment.Of 98 acquired DR TB patients.38(38.8%)LFU,4(4.1%)died,and 17(17.3%)failed treatment.However,the difference in mortality rate was not statistically significant between these two group(p>0.05).Conclusion:Acquired drug resistance appear rapidly during TB treatment.Programmatic efforts to optimize the policy of TB treatment and control were vital particularly at the early stage of diagnosed TB.Reduce unnecessary hospitalization and strengthen management for patients with cavity lesions were vital to prevent amplifying drug-resistance and improve treatment outcome.