Species distribution characteristics of nontuberculous mycobacteria isolated from patients with acquired immunodeficiency syndrome in Shanghai / 中华传染病杂志

ABSTRACT

Objective To investigate the species distribution characteristics of nontuberculous mycobacteria(NTM)in acquired immunodeficiency syndrome(AIDS)patients in Shanghai,and to provide evidences for clinical treatment.Methods A total of 775 Mycobacteria strains were isolated from patients(including 129 isolates from AIDS patients and 646 isolates from HIV-negative patients)admitted to Shanghai Public Health Clinical Center during 2015.All the species were identified by the sequence analysis of 16S rRNA gene and hsp65 gene.Differences in the species distribution were compared between patients with and without HIV infection.CD4+T lymphocyte count was detected by flow cytometry and its relation with mycobacteria infection was also analyzed.Chi-square test was used for comparison between groups.Results The ratio of NTM isolation from HIV-negative patients was 15.79%(102/646),while that was 46.51% in AIDS patients(60/129),and the difference was statistically significant(x2=61.38,P <0.01).Among the 60 NTM strains isolated from AIDS patients,mycobacterium avium-intracelluare complex(MAC)and Mycobacterium gordonae were the predominant species(43.33% and 20.00%,respectively).Moreover,five Mycobacterium colombiense strains,which were relatively rare,were also obtained.A total of 102 NTM were identified from HIV-negative patients,of which Mycobacterium gordonae(32 isolates,31.37%)and MAC(30 isolates,29.41%)were the most frequently isolated.In addition,the positive rates of NTM and MAC were significantly higher in patients with CD4+T lymphocyte counts ≤50 cells/μL(58.33% and 76.92%,respectively)than those with CD4+T lymphocyte counts>50 cells/μL(20.00% and 15.38%,respectively)(x2=4.048 and 6.524,respectively,both P<0.05).Four out of five Mycobacterium colombiense infected patients died of disseminated infections,except the remaining one whose CD4+T lymphocyte counts>50 cells/μL.Conclusions The prevalence of NTM isolation is significant higher in AIDS patients than HIV-negative patients in Shanghai,and the most prevalent NTM species is MAC.The NTM infection in AIDS patients is related with low CD4+T lymphocyte counts.