02631nas a2200301   4500000000100000008004100001260001200042653002400054653001900078653001200097653003200109653003000141653001700171100002100188700001300209700001100222700001200233700001500245700001300260700001400273700001200287245014500299856008300444300001100527490000700538520177000545022001402315       2022                            d  c06/202210aBacilloscopic index10aDNA extraction10aleprosy10aMicrobial Sensitivity Tests10apolymerase chain reaction10aTherapeutics1 aSevilha-Santos L1 aAquino D1 aNeto G1 aCosta F1 ade Sousa C1 aMorelo E1 aJúnior A1 aGomes C00aSensitivity of different DNA extraction methods and PCR to detect resistance in patients with leprosy stratified by the bacilloscopic index.  uhttps://www.sciencedirect.com/science/article/pii/S141386702200068X?via%3Dihub  a1023810 v263 a<p><strong>INTRODUCTION: </strong>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.</p>

<p><strong>METHODS: </strong>Patients with leprosy were included and divided into two groups depending on their BIs (≥ 2+ and &lt; 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.</p>

<p><strong>RESULTS: </strong>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&nbsp;&lt;&nbsp;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.</p>

<p><strong>CONCLUSIONS: </strong>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 &lt; 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.</p>
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