James M J, Lasker B A, McNeil M M, Shelton M, Warnock D W, Reiss E
Mycotic Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
J Clin Microbiol. 2000 Oct;38(10):3612-8. doi: 10.1128/JCM.38.10.3612-3618.2000.
Aspergillus flavus is second to A. fumigatus as a cause of invasive aspergillosis, but no standard method exists for molecular typing of strains from human sources. A repetitive DNA sequence cloned from A. flavus and subcloned into a pUC19 vector, pAF28, was used to type 18 isolates from diverse clinical, environmental, and geographic sources. The restriction fragment length polymorphisms generated with EcoRI- or PstI-digested genomic DNA and probed with digoxigenin-labeled pAF28 revealed complete concordance between patterns. Eighteen distinct fingerprints were observed. The probe was used to investigate two cases of cutaneous A. flavus infection in low-birth-weight infants in a neonatal intensive care unit (NICU). Both infants were transported by the same ambulance and crew to the NICU on the same day. A. flavus strains of the same genotype were isolated from both infants, from a roll of tape used to fasten their umbilical catheters, from a canvas bag used to store the tape in the ambulance, and from the tape tray in the ambulance isolette. These cases highlight the need to consider exposures in critically ill neonates that might occur during their transport to the NICU and for stringent infection control practices. The hybridization profiles of strains from a second cluster of invasive A. flavus infections in two pediatric hematology-oncology patients revealed a genotype common to strains from a definite case patient and a health care worker. A probable case patient was infected with a strain with a genotype different from that of the strain from the definite case patient but highly related to that of an environmental isolate. The high degree of discrimination and reproducibility obtained with the pAF28 probe underscores its utility for typing clinical and environmental isolates of A. flavus.
黄曲霉是侵袭性曲霉病的第二大病因，仅次于烟曲霉，但目前尚无针对来自人类源菌株的分子分型标准方法。从黄曲霉中克隆的一个重复DNA序列被亚克隆到pUC19载体pAF28中，用于对来自不同临床、环境和地理来源的18株分离株进行分型。用EcoRI或PstI消化基因组DNA并用地高辛标记的pAF28进行杂交，结果显示酶切图谱完全一致。共观察到18种不同的指纹图谱。该探针被用于调查新生儿重症监护病房（NICU）中两例低体重儿皮肤黄曲霉感染病例。两名婴儿于同一天由同一辆救护车及救护人员转运至NICU。从两名婴儿、用于固定其脐静脉导管的一卷胶带、救护车上用于存放胶带的帆布袋以及救护暖箱中的胶带托盘上均分离出相同基因型的黄曲霉菌株。这些病例凸显了需要考虑重症新生儿在转运至NICU过程中可能发生的暴露情况，并采取严格的感染控制措施。对两名儿科血液肿瘤患者中另一组侵袭性黄曲霉感染菌株的杂交图谱分析显示，一名确诊病例患者和一名医护人员的菌株具有相同基因型。一名疑似病例患者感染的菌株基因型与确诊病例患者的不同，但与一株环境分离株的基因型高度相关。pAF28探针所具有的高度鉴别力和可重复性突出了其在黄曲霉临床和环境分离株分型中的应用价值。
