Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India.
Department of Microbiology, Indraprastha Apollo Hospitals, Delhi, India.
J Infect Dev Ctries. 2020 Feb 29;14(2):214-222. doi: 10.3855/jidc.10169.
Nocardia otitidiscaviarum is a rare cause of human infections, mostly causing cutaneous and lymphocutaneous infections of mild severity. We report two cases of fatal pulmonary infection caused by Nocardia otitidiscaviarum in elderly patients.
Case 1: A 70-year old woman presented with fever and cough with expectoration for a month. On physical examination, she had tachypnea and inspiratory crepitations in bilateral basal regions. Case 2: A 74-year old man presented with productive cough with foul smelling expectoration, fever and shortness of breath for one week. On examination, he had tachypnea, bilateral wheezing and inspiratory crepitations. In both cases, sputum was sent to microbiology laboratory. On direct microscopy Gram-positive, finely branching filaments were observed which were acid fast with 1% sulphuric acid. Chalky white opaque wrinkled colonies with musty basement type odour were seen on blood agar. Both patients were treated empirically with trimethoprim-sulfamethoxazole for Nocardia infection after notification of microscopy findings however both expired on Day 2 and Day 5 of admission, respectively. Both isolates were susceptible to amikacin, linezolid, ciprofloxacin and gentamicin. They were resistant to trimethoprim-sulfamethoxazole, ampicillin, amoxicillin-clavulanic acid, erythromycin, and imipenem. Based on biochemical identification and antimicrobial susceptibility pattern, the organism was identified as Nocardia otitidiscaviarum. The identification was confirmed using MALDI-TOF (Vitek MS, Biomerieux, France).
Our report highlights the importance of early identification of Nocardia to species level to improve treatment outcomes especially in critically ill patients. Mass spectrometry can become an integral part of diagnostic algorithms for nocardiosis.
鼻疽奴卡菌是一种罕见的人类感染病原体，主要引起轻度皮肤和淋巴管皮肤感染。我们报告两例老年患者由鼻疽奴卡菌引起的致命性肺部感染。
病例 1：一名 70 岁女性，因发热和咳嗽伴咳痰 1 个月就诊。体格检查时，她在双侧基底部有呼吸急促和吸气性爆裂音。病例 2：一名 74 岁男性，因咳嗽有脓性痰、有臭味、发热和呼吸困难 1 周就诊。检查时，他有呼吸急促、双侧哮鸣和吸气性爆裂音。在这两种情况下，都将痰液送到微生物实验室。直接显微镜检查发现革兰阳性、细分支丝状，用 1%硫酸抗酸染色阳性。血琼脂上可见白垩色不透明皱缩菌落，有发霉的基底样气味。在显微镜检查结果通知后，两名患者均经验性地接受了复方磺胺甲噁唑治疗奴卡菌感染，但分别在入院第 2 天和第 5 天死亡。两种分离株均对阿米卡星、利奈唑胺、环丙沙星和庆大霉素敏感。它们对复方磺胺甲噁唑、氨苄西林、阿莫西林克拉维酸、红霉素和亚胺培南耐药。根据生化鉴定和药敏模式，该病原体被鉴定为鼻疽奴卡菌。通过 MALDI-TOF（Vitek MS，生物梅里埃，法国）鉴定确认了该鉴定。
我们的报告强调了早期鉴定奴卡菌至种水平以改善治疗结果的重要性，尤其是在重症患者中。质谱分析可以成为奴卡菌病诊断算法的一个组成部分。
