Studies of antimicrobial resistance in rare mycobacteria from a nosocomial environment
Studies of antimicrobial resistance in rare mycobacteria from a nosocomial environment
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DOI：
10.1186/s12866-019-1428-4
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发表时间：
2019-03-19
期刊：
影响因子：
4.2
通讯作者：
Empadinhas, Nuno
中科院分区：
文献类型：
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作者：
Pereira, Sonia Goncalves;Alarico, Susana;Empadinhas, Nuno
背景非结核分枝杆菌(NTM)在自然界中普遍存在，是机会性感染的公认病原体，由于其对抗生素的内在耐药性、治疗策略的不明确以及缺乏新药而加剧了机会性感染。然而，对它们在人为环境中的流行率和相关的抗菌素耐药性图谱的评估被忽视了。在这项工作中，我们试图确定25种抗菌剂对5株从三级护理医院表面分离的NTM菌株的最低抑菌浓度。从同一医院分离的另外5株棒状杆菌也进行了药敏试验。结果我们对每一株NTM分离株的系统发育研究证实它们属于结核分枝杆菌、粘生分枝杆菌和副冠状分枝杆菌，后者最初被误认为戈登分枝杆菌的菌株，该种经常从葡萄牙的NTM病患者中分离出来。与其他菌株不同，这里检查的母牛分枝杆菌和粘生分枝杆菌对CLSI推荐的几种药物具有耐药性，这表明存在多重耐药特征。令人惊讶的是，牛分枝杆菌对万古霉素敏感。对它们的基因组进行了测序，可以检测到牛分枝杆菌中的erm(红霉素抗性甲基酶)基因，解释了它对克拉霉素的抗性。与该属其他菌株不同的是，棒状杆菌分离株对青霉素、环丙沙星和利奈唑胺高度耐药。结论本研究强调了采取有效措施筛选、准确鉴定和控制医院环境中NTM活菌和密切相关细菌的重要性。我们关于罕见的NTM菌株的报告表明，耐药性可能比之前认为的更常见，也是对虚弱和脆弱的住院患者的潜在威胁。这些稀有NTM物种的抗生素敏感性谱与相应的类型菌株不同，同时检测到了意想不到的耐药性机制。
BackgroundNontuberculous mycobacteria (NTM) are ubiquitous in nature and recognized agents of opportunistic infection, which is often aggravated by their intrinsic resistance to antimicrobials, poorly defined therapeutic strategies and by the lack of new drugs. However, evaluation of their prevalence in anthropogenic environments and the associated antimicrobial resistance profiles have been neglected. In this work, we sought to determine minimal inhibitory concentrations of 25 antimicrobials against 5 NTM isolates recovered from a tertiary-care hospital surfaces. Antimicrobial susceptibilities of 5 other Corynebacterineae isolated from the same hospital were also determined for their potential clinical relevance.ResultsOur phylogenetic study with each of the NTM isolates confirm they belong to Mycobacterium obuense, Mycobacterium mucogenicum and Mycobacterium paragordonae species, the latter initially misidentified as strains of M. gordonae, a species frequently isolated from patients with NTM disease in Portugal. In contrast to other strains, the M. obuense and M. mucogenicum examined here were resistant to several of the CLSI-recommended drugs, suggestive of multidrug-resistant profiles. Surprisingly, M. obuense was susceptible to vancomycin. Their genomes were sequenced allowing detection of gene erm (erythromycin resistance methylase) in M. obuense, explaining its resistance to clarithromycin. Remarkably, and unlike other strains of the genus, the Corynebacterium isolates were highly resistant to penicillin, ciprofloxacin and linezolid.ConclusionsThis study highlights the importance of implementing effective measures to screen, accurately identify and control viable NTM and closely related bacteria in hospital settings. Our report on the occurrence of rare NTM species with antibiotic susceptibility profiles that are distinct from those of the corresponding Type strains, along with unexpected resistance mechanisms detected seem to suggest that resistance may be more common than previously thought and also a potential threat to frail and otherwise vulnerable inpatients.