Ghalavand Zohreh, Heidary Rouchi Alireza, Bahraminasab Hassan, Ravanasa Elham, Mirsamadi Elnaz Sadat, Nodeh Farahani Narges, Nikmanesh Bahram
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Cell Tissue Bank. 2018 Sep;19(3):391-398. doi: 10.1007/s10561-018-9684-3. Epub 2018 Feb 3.
Microbiological screening of tissue allografts is crucial to prevent the transmission of bacterial and fungal infections to transplant recipients. Klebsiella was the most prevalent and resistant contaminating microorganism observed in our setting in the Iranian Tissue Bank. This study was conducted to determine the presence of extended-spectrum β-lactamase (ESBL) genes, antimicrobial resistance patterns of Klebsiella pneumoniae isolates, and their clonal relationships in allograft materials. K. pneumoniae contaminating bone and other tissue allografts recovered from deceased donors were identified and ESBL isolates were detected using a phenotypic confirmatory method. Antimicrobial susceptibility testing was carried out using the disk diffusion method. Distribution of ESBL genes and molecular typing were performed using polymerase chain reaction (PCR) and Repetitive-element (rep-PCR) methods. Of 3828 donated tissues, 51 (1.3%) were found contaminated by K. pneumoniae isolates. Compared to tissue allografts from brain-dead, heart-beating tissue donors, allografts from donors with circulatory cessation were associated with a higher risk of K. pneumoniae contamination [odds ratio (OR), 1.2 (CI 95% 0.9-2.3) (P value < 0.001)]. Half of the isolates produced ESBL, and the rate of susceptibility to cephalosporins was 51%. Among isolates, 22 (43.1%) harbored CTX-M, 31 (60.8%) SHV, and 9 (17.6%) harbored TEM types. The rep-dendrogram indicated that clones having identical or related strains with a similar antibiotype were isolated in the same period. This study provides evidence that a single clone of K. pneumoniae contaminated tissue allografts recovered from many different donors. A single clone found on tissues from several donors suggests contamination of tissues from a single source such as the tissue recovery process and environment. Genomic DNA testing and clonality of contaminating bacteria using molecular methods can focus the epidemiologic investigation on the tissue allograft recovery process including a search for contamination of the tissue recovery room environment, recovery staff, recovery equipment, reagents, solutions and supplies.
对组织同种异体移植物进行微生物筛查对于防止细菌和真菌感染传播给移植受者至关重要。克雷伯菌是我们在伊朗组织库中观察到的最普遍且具有耐药性的污染微生物。本研究旨在确定超广谱β-内酰胺酶（ESBL）基因的存在、肺炎克雷伯菌分离株的抗菌耐药模式及其在同种异体移植材料中的克隆关系。对从已故供体回收的污染骨和其他组织同种异体移植物的肺炎克雷伯菌进行鉴定，并使用表型确证方法检测ESBL分离株。采用纸片扩散法进行抗菌药敏试验。使用聚合酶链反应（PCR）和重复元件（rep-PCR）方法进行ESBL基因分布和分子分型。在3828份捐赠组织中，发现51份（1.3%）被肺炎克雷伯菌分离株污染。与来自脑死亡、心脏仍在跳动的组织供体的组织同种异体移植物相比，来自循环停止供体的同种异体移植物肺炎克雷伯菌污染风险更高[优势比（OR），1.2（95%CI 0.9 - 2.3）（P值<0.001）]。一半的分离株产生ESBL，对头孢菌素的敏感率为51%。在分离株中，22株（43.1%）携带CTX-M，31株（60.8%）携带SHV，9株（17.6%）携带TEM型。rep-树形图表明，具有相同或相关菌株且具有相似抗菌型的克隆在同一时期被分离出来。本研究提供了证据，表明单一克隆的肺炎克雷伯菌污染了从许多不同供体回收的组织同种异体移植物。在来自多个供体的组织上发现的单一克隆表明组织受到单一来源的污染，如组织回收过程和环境。使用分子方法对污染细菌进行基因组DNA检测和克隆性分析可将流行病学调查聚焦于组织同种异体移植物回收过程，包括寻找组织回收室环境、回收人员、回收设备、试剂、溶液和用品的污染情况。
