Faculdade de Medicina, Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, DF, Brazil.
Universidade de Brasília, Hospital Universitário de Brasília, Brasília, DF, Brazil.
Braz J Infect Dis. 2022 Jul-Aug;26(4):102381. doi: 10.1016/j.bjid.2022.102381. Epub 2022 Jun 27.
Antimicrobial resistance in leprosy is an emerging problem, and the quantitative impact of low bacilloscopic indexes (BIs) on the sensitivity of molecular tests is unknown. We aimed to evaluate the sensitivity of gene sequencing for the detection of mutations related to antimicrobial resistance in Mycobacterium leprae in patients with low BIs using an analytical model.
Patients with leprosy were included and divided into two groups depending on their BIs (≥ 2+ and < 2+). The sensitivities of the two DNA extraction methods were compared after amplifying and sequencing the repetitive element (RLEP), folP1, rpoB and gyrA in M. leprae.
We included 56 patients with leprosy: 35 had BIs less than 2+ (22 had negative slit-skin smear [SSS] results) and 21 patients had BIs greater than or equal to 2+. The sensitivity of the amplification of the RLEP target and the gene sequencing of folP1, rpoB and gyrA was 50 to 70% lower in patients with a BI less than 2+ and was significantly reduced in patients with lower BIs for all targets (p < 0.001). One patient had a mutation in the folP1 gene, and 14 patients had mutations in the gyrA gene, but no mutations related to antimicrobial resistance were found.
We can conclude that the sensitivity of molecular tests is directly related to the BI, but these tests can still detect up to 20% of the targets in patients with BIs < 2+. New strategies to improve the sensitivity for detecting antimicrobial resistance in leprosy patients and reasonable clinical criteria for follow-up and the introduction of alternative treatments must be developed.
麻风分枝杆菌的耐药性是一个新出现的问题，低细菌学指数（BI）定量对分子检测敏感性的影响尚不清楚。我们旨在使用分析模型评估在低 BI 患者中检测与麻风分枝杆菌耐药性相关突变的基因测序的敏感性。
纳入麻风病患者，并根据 BI（≥2+和<2+）将其分为两组。在扩增和测序重复元件（RLEP）、folP1、rpoB 和 gyrA 后，比较两种 DNA 提取方法的敏感性。
我们纳入了 56 例麻风病患者：35 例 BI 小于 2+（22 例有阴性皮肤划痕液[SSS]结果），21 例 BI 大于或等于 2+。在 BI 小于 2+的患者中，RLEP 靶标扩增和 folP1、rpoB 和 gyrA 基因测序的敏感性降低 50%至 70%，所有靶标（p<0.001）的敏感性均显著降低。1 例患者存在 folP1 基因突变，14 例患者存在 gyrA 基因突变，但未发现与抗菌药物耐药性相关的突变。
我们可以得出结论，分子检测的敏感性与 BI 直接相关，但这些检测仍可在 BI<2+的患者中检测到高达 20%的目标。必须开发新的策略来提高检测麻风病患者抗菌药物耐药性的敏感性，以及合理的临床随访和引入替代治疗的标准。
