Niyazi Denis, Vergiev Stoyan, Markovska Rumyana, Stoeva Temenuga
Clinical Microbiology Laboratory, University Hospital "St. Marina"-Varna, 9010 Varna, Bulgaria.
Department of Microbiology and Virology, Medical University-Varna, 9002 Varna, Bulgaria.
Antibiotics (Basel). 2024 Sep 26;13(10):920. doi: 10.3390/antibiotics13100920.
: Intestinal colonization by multidrug-resistant (MDR) bacteria is considered one of the main risk factors for invasive infections in the hematopoietic stem-cell transplant (HSCT) setting, associated with hard-to-eradicate microorganisms. The aim of this study was to assess the rate of intestinal colonization by MDR bacteria and their microbial spectrum in a group of post-HSCT patients to study the genetic determinants of beta-lactam and glycopeptide resistance in the recovered isolates, as well as to determine the epidemiological relation between them. : The intestinal colonization status of 74 patients admitted to the transplantation center of University Hospital "St. Marina"-Varna in the period January 2019 to December 2021 was investigated. Stool samples/rectal swabs were screened for third-generation cephalosporin and/or carbapenem-resistant Gram-negative bacteria, methicillin-resistant (MRSA), vancomycin-resistant enterococci (VRE), and . Identification and antimicrobial susceptibility testing were performed by Phoenix (BD, Sparks, MD, USA) and MALDI Biotyper sirius (Bruker, Bremen, Germany). Molecular genetic methods (PCR, DNA sequencing) were used to study the mechanisms of beta-lactam and glycopeptide resistance in the collected isolates, as well as the epidemiological relationship between them. : A total of 28 patients (37.8%) were detected with intestinal colonization by MDR bacteria. Forty-eight non-duplicate MDR bacteria were isolated from their stool samples. Amongst them, the Gram-negative bacteria prevailed (68.8%), dominated by ESBL-producing (30.3%), and followed by carbapenem-resistant sp. (24.2%). The Gram-positive bacteria were represented exclusively by (31.2%). The main beta-lactam resistance mechanisms were associated with CTX-M and VIM production. was detected in all vancomycin-resistant enterococci. A clonal relationship was observed among complex and among isolates. : To the best of our knowledge, this is the first Bulgarian study that presents detailed information about the prevalence, resistance genetic determinants, and molecular epidemiology of MDR gut-colonizing bacteria in HSCT patients.
耐多药（MDR）细菌在肠道的定植被认为是造血干细胞移植（HSCT）环境中侵袭性感染的主要危险因素之一，与难以根除的微生物有关。本研究的目的是评估一组HSCT术后患者中耐多药细菌的肠道定植率及其微生物谱，研究分离菌株中β-内酰胺和糖肽耐药性的遗传决定因素，并确定它们之间的流行病学关系。
对2019年1月至2021年12月期间入住瓦尔纳市“圣玛丽娜”大学医院移植中心的74例患者的肠道定植状况进行了调查。对粪便样本/直肠拭子进行筛查，以检测对第三代头孢菌素和/或碳青霉烯耐药的革兰氏阴性菌、耐甲氧西林金黄色葡萄球菌（MRSA）、耐万古霉素肠球菌（VRE）等。通过Phoenix（美国马里兰州斯帕克斯市BD公司）和MALDI Biotyper sirius（德国不来梅市布鲁克公司）进行鉴定和抗菌药敏试验。采用分子遗传学方法（PCR、DNA测序）研究收集的分离菌株中β-内酰胺和糖肽耐药机制，以及它们之间的流行病学关系。
共有28例患者（37.8%）被检测出肠道有耐多药细菌定植。从他们的粪便样本中分离出48株非重复的耐多药细菌。其中，革兰氏阴性菌占优势（68.8%），以产超广谱β-内酰胺酶（ESBL）的菌株为主（30.3%），其次是耐碳青霉烯类肠杆菌科细菌（24.2%）。革兰氏阳性菌仅由屎肠球菌代表（31.2%）。主要的β-内酰胺耐药机制与CTX-M和VIM的产生有关。在所有耐万古霉素肠球菌中均检测到vanA。在肺炎克雷伯菌复合体和屎肠球菌分离株之间观察到克隆关系。
据我们所知，这是保加利亚第一项提供HSCT患者中耐多药肠道定植细菌的患病率、耐药遗传决定因素和分子流行病学详细信息的研究。
