Abstract:

Objective: To explore the clinical characteristics of mycobacterium bloodstream infection in AIDS patients and to improve the differential diagnosis of Mycobacterium tuberculosis (MTB) and nontuberculous mycobacteria (NTM) infection. Methods: A retrospective survey was conducted in 135 AIDS patients with mycobacterium bloodstream infection admitted to Beijing Youan Hospital from June 2016 to June 2021. The clinical data, including medical history, symptoms, signs, laboratory results, etiological characteristics, imaging characteristics and treatment were collected and the data of MTB patients and NTM patients were analyzed and compared. Results: (1) Etiological examination: among the 135 patients, 64 (47.4%) were infected with MTB and 71 (52.6%) were infected with NTM. Mycobacterium avium was dominant in NTM isolates (40 strains, 56.3%). (2) Clinical manifestations: the main clinical manifestations of those patients were fever (83.7%, 113/135), followed with cough (44.4%, 60/135), fatigue (30.4%, 41/135), diarrhea (25.2%, 34/135), etc. The incidence rate of fever, cough, expectoration and the peak body temperature in MTB infection group were significantly higher than those of NTM group (92.2% (59/64) vs. 76.1% (54/71), χ²=6.421, P=0.011; 56.3% (36/64) vs. 33.8% (24/71), χ²=6.869, P=0.009; 32.8% (21/64) vs. 11.3% (8/71), χ²=9.263, P=0.002; and (39.0±1.0) ℃ vs. (38.6±1.2) ℃, t=2.025, P=0.045, respectively). (3) Laboratory examination: procalcitonin, white blood cell count, hemoglobin and positive rate of smear acid-fast in MTB group were significantly higher than those in NTM group (1.57 (0.42, 6.71) ng/ml vs. 0.31 (0.11, 1.80) ng/ml, Z=-3.433, P=0.001; 6.62 (3.39, 8.78)×10⁹/L vs. 4.03 (2.81, 6.20)×10⁹/L, Z=2.798, P=0.005; (95.5±21.5) g/L vs. (78.7±14.6) g/L, t=5.344, P<0.001; 45.3% (29/64) vs. 11.2% (8/71), χ²=19.609, P<0.001, respectively), and the differences were statistically significant. There was significant difference on the CD4⁺ T lymphocyte count between the MTB group and the NTM group (14 (8, 55)×10⁶/L vs. 7 (2, 20)×10⁶/L, Z=-3.434, P=0.001). (4) Imaging findings: the incidence of miliary shadow and thoracic lymph node enlargement in MTB group was higher than that in NTM group (17.2% (11/64) vs. 1.4% (1/71) and 85.9% (55/64) vs. 71.8% (51/71)), and the differences were statistically significant (χ² values were 8.491 and 3.971, P values were 0.004 and 0.046, respectively). (5) Treatment outcome: the length of hospital stay in the MTB group was 18 (8,25) d, significantly shorter than that in the NTM group (26 (15,38) d), and the difference was statistically significant (Z=-3.344, P=0.001). The mortality rate of MTB group was 17.2% (11/64), which was significantly higher than that of NTM group (2.8% (2/71), χ²=5.328, P=0.021). Conclusion: Mycobacterium bloodstream infection should be constantly paid attention among AIDS patients with significantly reduced CD4⁺ T lymphocytes, if they concurrent fever, cough and expectoration, significantly increased inflammatory indicators, anemia, hypoproteinemia and typical imaging changes in the lungs. There are some differences of the clinical manifestations and laboratory indices between MTB and NTM infection, but lack of specificity.

Key words: Acquired immunodeficiency syndrome, Mycobacterium, Bacterial infections, Disease attributes, Diagnosis, differential