Adaleti Rıza, Kansak Nilgün, Arıcı Neslihan, Balıkçı Ahmet, Uzunöner Yasemin, Aksaray Sebahat
University of Health Sciences Hamidiye Faculty of Medicine, Department of Medical Microbiology, İstanbul, Türkiye.
University of Health Sciences, Haydarpaşa Numune Training and Research Hospital, Laboratory of Medical Microbiology, İstanbul, Türkiye.
Mikrobiyol Bul. 2023 Oct;57(4):682-689. doi: 10.5578/mb.20239956.
Mycobacterium abscessus (M.abscessus), which is from the group of non-tuberculosis mycobacteria and is widely found in the natural environment, has been reported with increasing frequency as the causative agent of various infections; especially in the lower respiratory tract and in immuncompromised people. In this report, a case of M.abscessus, which developed tubular adenoma, pancytopenia and sepsis on the basis of chronic renal failure (CRF) was diagnosed by suspecting the causative agent in the Gram stain examination prepared from blood culture, was presented. A 49-year-old patient with CRF, who had complaints of weight loss, weakness, and loss of appetite for the last six months, admitted to the emergency department with a 7-8-day history of severe diarrhea and fever. Besides other tests, as the white blood cell count was 1.6 x 103/µl, neutrophil count was 80.6%, hemoglobin was 9.3 g/ dl and the platelet value was 36 x 103/µl in the blood samples, the patient was first taken into internal medicine service and then to the intensive care unit with a preliminary diagnosis of hypotension and sepsis. Meropenem and teicoplanin were started with the preliminary diagnosis of peritonitis in the internal medicine service. In addition to other tests, on the fifth day of antibiotic treatment, two consecutive sets of blood cultures were taken and sent to the microbiology laboratory. A positive signal was obtained from two aerobic blood culture samples at 42 and 45 hours of incubation in the BacT/Alert device. No bacteria were observed in the Gram staining of these samples and Erhlich Ziehl Neelsen (EZN) staining was performed because the structures considered as dye residues were noted as a result of the examination. Acid-fast bacteria were observed in the EZN-stained slide examination, and a panic report was given to the clinician. The patient died shortly after the notification was made in the evening hours. On culture plates inoculated after a positive signal, at the end of two days of aerobic incubation at 37 °C, small smooth S colonies grew on chocolate and sheep blood agar. Growing bacteria were detected as positive by EZN staining and identified as M.abscessus with 99.9% confidence by MALDI-TOF MS. After the bacterium was named as M.abscessus, the isolates were sent to the tuberculosis central laboratory of Süreyyapaşa Chest Diseases and Thoracic Surgery Hospital for molecular typing. After DNA extraction from the growing colonies and polymerase chain reaction (PCR), they were typed using the GenoType NTM-DR (Hain Lifescience GmbH, Germany) kit and identified as M.abscessus, consistent with the MALDITOF MS result. After the species level identification, the erm, rrl (clarithromycin, azithromycin), and rrs (kanamycin, amikacin, and gentamicin) genes were investigated in the isolate, and it was determined that the bacteria were resistant to macrolides and sensitive to aminoglycosides. In the clinic, it should be noted that, non-tuberculous mycobacteria may play a role as an agent in immunocompromised people. On the other hand, it should be considered that non-tuberculosis bacteria may be the causative agent, with gram-positive bacilli appearing as stain residues or pale staining in Gram stains made from samples of such patients. As in this case, if the agent is seen as dye residue in blood culture Gram staining samples, it may be life-saving to suspect the agent and to report the result to the clinician accurately and quickly after EZN staining.
脓肿分枝杆菌(M.abscessus)属于非结核分枝杆菌组,广泛存在于自然环境中,作为各种感染的病原体,其报道频率日益增加;尤其是在下呼吸道感染以及免疫功能低下人群中。在本报告中,呈现了一例基于慢性肾衰竭(CRF)并发管状腺瘤、全血细胞减少和败血症的脓肿分枝杆菌病例,该病例是通过对血培养制备的革兰氏染色检查中的病原体进行怀疑而诊断出来的。一名49岁的CRF患者,在过去六个月中出现体重减轻、乏力和食欲不振的症状,因严重腹泻和发热7 - 8天而入住急诊科。除其他检查外,血液样本中白细胞计数为1.6×10³/µl,中性粒细胞计数为80.6%,血红蛋白为9.3 g/dl,血小板值为36×10³/µl,该患者首先被收入内科,随后因初步诊断为低血压和败血症而转入重症监护病房。在内科,根据腹膜炎的初步诊断开始使用美罗培南和替考拉宁。除其他检查外,在抗生素治疗的第五天,连续采集两组血培养样本并送至微生物实验室。在BacT/Alert装置中,两份需氧血培养样本在孵育42小时和45小时时获得阳性信号。这些样本的革兰氏染色未观察到细菌,由于检查时注意到被视为染料残渣的结构,因此进行了厄利希齐尔-尼尔森(EZN)染色。在EZN染色玻片检查中观察到抗酸杆菌,并向临床医生发出了紧急报告。在晚上通知后不久患者死亡。在获得阳性信号后接种的培养平板上,在37℃需氧培养两天后,巧克力琼脂和羊血琼脂上长出了小而光滑的S菌落。生长的细菌经EZN染色检测为阳性,并通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)以99.9%的置信度鉴定为脓肿分枝杆菌。在该细菌被命名为脓肿分枝杆菌后 , 将分离株送至苏雷亚帕夏胸科疾病与胸外科医院的结核病中央实验室进行分子分型。从生长的菌落中提取DNA并进行聚合酶链反应(PCR)后,使用GenoType NTM-DR(德国海因生命科学有限公司)试剂盒进行分型,鉴定为脓肿分枝杆菌,与MALDI-TOF MS结果一致。在进行种属鉴定后,对分离株中的erm、rrl(克拉霉素、阿奇霉素)和rrs(卡那霉素、阿米卡星和庆大霉素)基因进行了研究,确定该细菌对大环内酯类耐药,对氨基糖苷类敏感。在临床上,应注意非结核分枝杆菌可能在免疫功能低下人群中作为病原体起作用。另一方面,应考虑非结核细菌可能是病原体,在从此类患者样本制备的革兰氏染色中,革兰氏阳性杆菌表现为染色残渣或淡染。就像这个病例一样,如果在血培养革兰氏染色样本中病原体被视为染料残渣,怀疑该病原体并在EZN染色后准确快速地向临床医生报告结果可能会挽救生命。