ABSTRACT

Several Fusarium species cause disease on human hosts, including commonly fatal infections in immunocompromised individuals. Recently, cases of hospitalized patients affected by fusaria were reported in the Tyrrhenian Island of Sardinia, Italy. To precisely characterize the Fusarium species and haplotypes present in hospitals of the region, a multilocus DNA sequence typing (MLST) approach was applied. Water distribution systems in four departments belonging to four Sardinian hospitals were sampled. Fusarium species and sequence types (STs) were identified using MLST based on sequences of the elongation factor 1-alpha (EF-1α) gene, the nuclear ribosomal DNA intergenic spacer region (IGS rDNA), and/or a portion of the second-largest subunit of RNA polymerase (RPB2) gene. The majority of isolates obtained from Sardinian hospitals (90.7%) were identified as representatives of the Fusarium oxysporum species complex (FOSC), followed by those of the F. solani species complex (FSSC) (8.2%), and F. dimerum (1.1% of all isolates). Ten STs were found among the FOSC and FSSC, with more than 60% of the isolates identified as either FOSC ST 33 or FSSC 1 (F. petroliphilum). More than half of the FOSC isolates obtained from the water systems in all four hospitals belonged to the worldwide distributed clonal lineage ST 33. This haplotype is the most prevalent among the FOSC in different countries, being responsible for the vast majority of cases of human fusariosis.

摘要

几种镰刀菌会导致人类宿主疾病，包括免疫功能低下个体的常见致命感染。最近，意大利撒丁岛的第勒尼安岛报告了感染镰刀菌的住院患者病例。为了精确表征该地区医院中存在的镰刀菌属物种和单倍型，应用了多位点 DNA 序列分型 (MLST) 方法。对属于撒丁岛四家医院的四个部门的供水系统进行了采样。镰孢属物种和序列类型（STS），使用基于该延伸因子1-α的序列鉴定MLST（EF-1α) 基因、核糖体 DNA 基因间隔区 (IGS rDNA) 和/或 RNA 聚合酶 ( RPB2 ) 基因的第二大亚基的一部分。从撒丁岛医院获得的大多数分离株 (90.7%) 被确定为尖孢镰刀菌种复合体 (FOSC) 的代表，其次是茄病镰孢菌种复合体 (FSSC) (8.2%) 和二聚体镰刀菌(1.1所有分离株的百分比）。在 FOSC 和 FSSC 中发现了 10 个 ST，其中超过 60% 的分离株被确定为 FOSC ST 33 或 FSSC 1（F. petroliphilum）。从所有四家医院的供水系统中获得的 FOSC 分离株中，有一半以上属于世界范围内分布的克隆谱系 ST 33。 这种单倍型在不同国家的 FOSC 中最为普遍，是造成绝大多数人类镰刀菌病病例的原因.