Introduction. Mycobacterium avium complex (MAC) has been reported as the most common aetiology of lung disease involving nontuberculous mycobacteria. Hypothesis. Antimicrobial susceptibility and clinical characteristics may differ between Mycobacterium avium and Mycobacterium intracellulare . Aim. We aimed to evaluate the differences in antimicrobial susceptibility profiles between two major MAC species ( Mycobacterium avium and Mycobacterium intracellulare ) from patients with pulmonary infections and to provide epidemiologic data with minimum inhibitory concentration (MIC) distributions. Methodology. Between January 2019 and May 2020, 45 M. avium and 242 M . intracellulare isolates were obtained from Shanghai Pulmonary Hospital. The demographic and clinical characteristics of patients were obtained from their medical records. The MICs of 13 antimicrobials were determined for the MAC isolates using commercial Sensititre SLOWMYCO MIC plates and the broth microdilution method, as recommended by the Clinical and Laboratory Standards Institute (CLSI; Standards M24-A2). MIC50 and MIC90 values were derived from the MIC distributions. Results. M. intracellulare had higher resistance rates than M. avium for most tested antimicrobials except clarithromycin, ethambutol, and ciprofloxacin. Clarithromycin was the most effective antimicrobial against both the M. avium (88.89 %) and M. intracellulare (91.32 %) isolates, with no significant difference between the species (P=0.601). The MIC90 of clarithromycin was higher for M. avium (32 µg ml−1) than M. intracellulare (8 µg ml−1). The MIC50 of rifabutin was more than four times higher for M. intracellulare (1 µg ml−1) than M. avium (≤0.25 µg ml−1). The percentages of patients aged >60 years and patients with sputum, cough, and cavitary lesions were significantly higher than among patients with M. intracellulare infection than M. avium infections. Conclusions. The pulmonary disease caused by distinct MAC species had different antimicrobial susceptibility, symptoms, and radiographic findings.

中文翻译：

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上海地区鸟分枝杆菌和细胞内分枝杆菌肺部疾病药敏性分布和临床特征的差异

介绍。 据报道，鸟分枝杆菌复合物（MAC）是涉及非结核分枝杆菌的最常见的肺部疾病病因。假设。鸟分枝杆菌和细胞内分支杆菌的抗菌敏感性和临床特征可能有所不同。目标。我们旨在评估来自肺部感染患者的两种主要MAC物种（鸟分枝杆菌和细胞内分枝杆菌）在抗菌药敏感性方面的差异，并提供具有最低抑制浓度（MIC）分布的流行病学数据。方法。 2019年1月和2020年5，45间鸟分枝杆菌和242中号。细胞内分离株购自上海肺科医院。患者的人口统计学和临床​​特征可从他们的病历中获得。按照临床和实验室标准协会（CLSI; Standards M24-A2）的建议，使用市售的Sensititre SLOWMYCO MIC板和肉汤微稀释法确定MAC分离物中13种抗微生物药物的MIC。MIC 50和MIC 90值是从MIC分布中得出的。结果。细胞内分枝杆菌的抗药性高于鸟分枝杆菌 适用于除克拉霉素，乙胺丁醇和环丙沙星以外的大多数经过测试的抗菌药物。克拉霉素是针对鸟分枝杆菌（88.89％）和胞内分枝杆菌（91.32％）分离物的最有效的抗菌剂，两种之间无显着差异（P = 0.601）。对于鸟分枝杆菌（32 µg ml -1），克拉霉素的MIC 90高于胞内分枝杆菌（8 µg ml -1）。的MIC 50利福布汀的较高的四倍以上为胞内分枝杆菌（1微克毫升-1）比鸟分枝杆菌（≤0.25微克毫升-1 ）。年龄大于60岁的患者以及有痰，咳嗽和空洞病变的患者的百分比显着高于胞内分枝杆菌感染的患者，高于鸟分枝杆菌感染的百分比。结论 由不同的MAC物种引起的肺部疾病具有不同的抗菌药敏性，症状和影像学发现。