Princivalli M S, Palmieri C, Magi G, Vignaroli C, Manzin A, Camporese A, Barocci S, Magistrali C, Facinelli B
Department of Biomedical Sciences, Polytechnic University of Marche Medical School, Ancona, Italy.
Euro Surveill. 2009 Aug 20;14(33):19310. doi: 10.2807/ese.14.33.19310-en.
Streptococcus suis, a major porcine pathogen, is emerging as a zoonotic agent capable of causing severe invasive disease in humans exposed to pigs or pork products. S. suis infection is rare in industrialised countries and usually arises as sporadic cases, with meningitis the most common clinical presentation in humans. Recent reports of two cases of meningitis in Sardinia and northeastern Italy prompted this first characterisation of Italian S. suis isolates. Fifty-nine S. suis strains, the two recent human strains and 57 swine clinical isolates collected between 2003 and 2007 from different Italian herds and regions, were tested for antimicrobial susceptibility, PCR-screened for virulence and antibiotic resistance genes, and subjected to molecular typing. Phenotypic and genotypic analysis demonstrated an overall high genetic diversity among isolates, the majority of which were resistant to macrolides (78%) and tetracyclines (90%). The erm(B), tet(O), mosaic tet(O/W/32/O), tet(W), and tet(M) genes were detected. The tet(O/W/32/O) gene, the most frequent tet gene after tet(O), had never been described in the genus Streptococcus before. In addition, a virulent cps2, erm(B) tet(O) clone, belonging to sequence type 1 (ST1) of the ST1 complex, was found to be prevalent and persistent in Italian swine herds. Finally, the two human isolates (both ST1) carrying cps2, erm(B) and tet(W) were seen to be closely related to each other.
猪链球菌是一种主要的猪病原体，正逐渐成为一种人畜共患病原体，能够在接触猪或猪肉产品的人类中引起严重的侵袭性疾病。在工业化国家，猪链球菌感染很少见，通常以散发病例出现，脑膜炎是人类最常见的临床表现。撒丁岛和意大利东北部最近报告的两例脑膜炎病例促使对意大利猪链球菌分离株进行了首次特征描述。对59株猪链球菌菌株（包括最近的两株人类菌株和2003年至2007年间从意大利不同猪群和地区收集的57株猪临床分离株）进行了抗菌药敏试验，通过PCR筛选毒力和抗生素耐药基因，并进行分子分型。表型和基因型分析表明，分离株之间总体遗传多样性较高，其中大多数对大环内酯类（78%）和四环素类（90%）耐药。检测到erm(B)、tet(O)、嵌合tet(O/W/32/O)、tet(W)和tet(M)基因。tet(O/W/32/O)基因是继tet(O)之后最常见的tet基因，此前从未在链球菌属中描述过。此外，发现一种属于ST1复合体序列类型1（ST1）的cps2、erm(B) tet(O) 强毒株克隆在意大利猪群中普遍存在且持续存在。最后，发现两株携带cps2、erm(B)和tet(W)的人类分离株（均为ST1）彼此密切相关。
