RÉSUMÉ
A 38-year-old female with systemic lupus erythematosus (SLE) initiated belimumab treatment. One month later, she presented with a reddish painful swelling on her right lower leg.She was treated with ceftriaxone and vancomycin. However, novel erythematous papules and indurated nodules appeared on both her lower legs. Skin biopsy revealed microabscess formation with mixed cell granuloma surrounded by inflammatory cell infiltration within the dermis with subcutaneous fat tissue. A large number of acid-fast bacilli were observed with Ziehl–Neelsen staining. DNA sequencing of both the hsp65 and the 16S rRNA sequences showed a 100% match with the corresponding region of Mycobacterium haemophilum. Mycobacterial culture revealed satellite growth enhancement on Middlebrook 7H11 agar plates around a paper strip containing hemin. She was treated with levofloxacin, rifabutin, and ethambutol. Within 13 months, her cutaneous lesions improved markedly without any side effects. The B cell-targeted biologic belimumab, a fully humanized IgG1γ monoclonal antibody that inactivates B lymphocyte stimulator, has been considered to be beneficial for active SLE. However, this therapy could increase the risk for the development of biologic therapy-associated mycobacterial infections, both tuberculosis and nontuberculous mycobacteria infections.
RÉSUMÉ
A concentration of specimen is recommended for the effective recovery of Mycobacterium tuberculosis [MTB], but the bacteriological efficiency is not well evaluated. The present study evaluated the factors contributing to concentration efficiency of centrifugation and bead-based technique [TB-Beads; Microsens, UK] to recover MTB by using simple in vitro specimens. Four specimens were prepared [6.5 × 103; 8.1 × 104; 7.9 × 105; and 6.4 × 106 cfu/mL] of different concentrations with or without 5 × 104 of THP-1 cells [RIKEN BRC, Japan]. Specimens were subjected to centrifugation at 2000, 3000, and 4000g for 15 min, and to TB-Beads. The concentration and recovery rate were calculated to evaluate the efficiency of each method. The specimens containing a higher number of bacteria and THP-1 cells had a tendency to yield a higher concentration and recovery rate [p = 0.001-0.083]. MTB was recovered more efficiently with THP-1 cells from the 6.5 × 103 cfu/mL specimen by centrifugation [p= 0.001] than without them; 24.7-54.4% of MTB were recovered with THP-1 cells by centrifugation at 3000g for 15 min, while the recovery using TB-Beads was a maximum of 12.7%. The efficiency of centrifugation depends on the bacterial density and the co-existence of THP-1 cells. The efficiency of TB-Beads was not as high as centrifugation