Mare Anca, Man Adrian, Toma Felicia, Ciurea Cristina Nicoleta, Coșeriu Răzvan Lucian, Vintilă Camelia, Maier Adrian Cornel
Department of Microbiology, Pharmacy, Sciences and Technology, George Emil Palade University of Medicine, 540142 Târgu Mureș, Romania.
Infectious Diseases Laboratory, Mureș County Clinical Hospital, 540233 Târgu Mureș, Romania.
Pathogens. 2020 Dec 4;9(12):1022. doi: 10.3390/pathogens9121022.
Even if serotyping based on O antigens is still routinely used by most laboratories for the detection of diarrheagenic , this method can provide false-positive reactions, due to the high diversity of O antigens. Molecular methods represent a valuable tool that clarifies these situations. In the Bacteriology Laboratory of Mureș County Hospital, between May 2016 and July 2019, 160 diarrheagenic strains were isolated from children under 2 years old with diarrheic disease. The strains were identified as Shiga toxin-producing (STEC)/enteropathogenic (EPEC) via agglutination with polyvalent sera. STEC strains were serotyped using monovalent sera for serogroup O157. Simplex PCR was performed on the strains to determine the presence of the gene, and, for the positive ones, the hemolytic activity was tested. Antibiotic susceptibility of the identified diarrheagenic strains was also investigated. STEC strains were the most frequently identified (49.1%), followed by EPEC (40.2%). The A gene was identified in 12 cases, representing 18.2% of the STEC strains. Even if the extended-spectrum β-lactamase (ESBL)-producing strains represented only 10%, a relevant percentage of multidrug-resistant (MDR) strains (24%) was identified.
即使大多数实验室仍常规使用基于O抗原的血清分型法来检测致泻性细菌，但由于O抗原的高度多样性，该方法可能会产生假阳性反应。分子方法是一种有助于厘清这些情况的宝贵工具。在穆列什县医院细菌学实验室，2016年5月至2019年7月期间，从2岁以下腹泻病患儿中分离出160株致泻性菌株。通过与多价血清凝集反应，将这些菌株鉴定为产志贺毒素大肠杆菌（STEC）/肠致病性大肠杆菌（EPEC）。使用O157血清群单价血清对STEC菌株进行血清分型。对这些菌株进行单重PCR以确定基因的存在，并对阳性菌株检测溶血活性。还对鉴定出的致泻性菌株进行了抗生素敏感性研究。STEC菌株是最常鉴定出的（49.1%），其次是EPEC（40.2%）。在12例中鉴定出A基因，占STEC菌株的18.2%。即使产超广谱β-内酰胺酶（ESBL）的菌株仅占10%，但仍鉴定出相当比例的多重耐药（MDR）菌株（24%）。
