PCR-based identification of Mycobacterium murphy causing Canine Leproid Granuloma Syndrome in Niterói, southeast Brazil - case report

ABSTRACT Canine Leproid Granuloma Syndrome (CLGS), also known as canine leprosy, is a cutaneous nodular infectious disease caused by Mycobacterium sp.. Despite being reported worldwide, it is still quite unknown and underdiagnosed. Diagnosis may be achieved by cytopathology or histopathology of skin lesions, but identification of the infectious agent is complex, since bacterial in vitro growth is not possible, relying upon molecular techniques such as PCR to confirm Mycobacterium DNA in the sample. We report a CLGS case in Niteroi, Rio de Janeiro state, Brazil, diagnosed by cytopathology and submitted to molecular identification of the agent. PCR amplification of hsp65 gene was performed and revealed 100% genetic homology to M. murphy strain. This is the first CLGS report with molecular identification in Rio de Janeiro state, and this finding should raise awareness about CLGS as a differential diagnosis among granulomatous skin diseases in this region.摘要：犬类麻风样肉芽肿综合征（Canine Leproid Granuloma Syndrome, CLGS），又称犬麻风病，是由分枝杆菌属（Mycobacterium sp.）引发的皮肤结节性传染性疾病。尽管该病在全球范围内均有报道，但目前仍鲜为人知且诊断不足。临床诊断可通过皮肤病变的细胞病理学或组织病理学检查实现，但由于该致病菌无法进行体外培养，感染原的鉴定工作较为复杂，需依赖聚合酶链式反应（PCR）等分子技术以确认样本中分枝杆菌DNA的存在。本文报告了巴西里约热内卢州尼泰罗伊市的一例CLGS病例，该病例经细胞病理学确诊，并完成了病原体的分子鉴定：研究人员对hsp65基因进行了PCR扩增，结果显示其与穆菲分枝杆菌（M. murphy）菌株的遗传同源性高达100%。本研究为里约热内卢州首例经分子鉴定确认的CLGS病例，该发现有助于提升当地临床医师将CLGS纳入肉芽肿性皮肤病鉴别诊断范畴的认知水平。