Dos Santos L F, Biscola F T, Gonçalves E M, Guth B E C
Adolfo Lutz Institute, Center of Bacteriology, Sao Paulo, Brazil.
Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil.
J Appl Microbiol. 2017 Apr;122(4):1101-1109. doi: 10.1111/jam.13409.
Although Shiga toxins (Stx) are well-established virulence traits of O113:H21 Shigatoxigenic Escherichia coli (STEC) strains, a shortage in the knowledge of other virulence properties that may contribute to pathogenesis may exist in this serotype. This study investigated biofilm, invasiveness and colicinogeny capabilities in O113:H21 STEC isolated in Brazil, mostly from animal reservoirs. A search for genes that were reported to participate in the process of biofilm formation was also performed.
The 34 O113:H21 STEC isolates analysed were assayed for biofilm production in polystyrene microplates. Genes for biofilm were investigated by PCR. Invasion of cell lineages was assessed in gentamicin protection assays and colicinogeny was investigated by phenotypic tests. Fifty per cent of the strains were biofilm formers, and 35% exhibited an invasive behaviour. The pattern of distribution of biofilm-related genes did not correlate with biofilm phenotypes observed, and a high percentage of the investigated strains were able to secrete colicins.
Ability to form biofilm, invasiveness and colicinogeny is demonstrated for the first time in a collection of O113:H21 STEC.
The ability to express three additional phenotypes besides Stx production may be a factor influencing the pathogenicity and persistence potential of O113:H21 STEC.
尽管志贺毒素（Stx）是O113:H21产志贺毒素大肠杆菌（STEC）菌株公认的毒力特征，但该血清型可能缺乏对其他可能导致发病机制的毒力特性的了解。本研究调查了巴西分离的O113:H21 STEC中的生物膜形成、侵袭性和产大肠杆菌素能力，这些菌株大多来自动物宿主。还对据报道参与生物膜形成过程的基因进行了搜索。
对34株O113:H21 STEC分离株在聚苯乙烯微孔板中检测生物膜形成情况。通过PCR研究生物膜相关基因。在庆大霉素保护试验中评估细胞系的侵袭情况，并通过表型试验研究产大肠杆菌素情况。50%的菌株形成生物膜，35%表现出侵袭性行为。生物膜相关基因的分布模式与观察到的生物膜表型不相关，且高比例的被研究菌株能够分泌大肠杆菌素。
首次在一组O113:H21 STEC中证明了形成生物膜、侵袭性和产大肠杆菌素的能力。
除了产生Stx外，表达另外三种表型的能力可能是影响O113:H21 STEC致病性和持续存在潜力的一个因素。
