Health Protection Agency Colindale, London, United Kingdom.
Euro Surveill. 2012 Sep 13;17(37):20275.
Difficulties in accurately identifying serovar 4,[5],12:i:- as monophasic variants of Salmonella enterica serovar Typhimurium mean there is confusion in the reporting of serovars Typhimurium and 4,[5],12:i:-. To gain insight into the prevalence and diversity of these monophasic variants in England and Wales, screening for fljB, hin and the serovar 4,[5],12:i:- DT193-associated genomic island was conducted on 609 S. enterica isolates designated as definitive phage type (DT) 193, and 142 isolates serologically-defined as monophasic variants of serovar Typhimurium but belonging to phage types other than DT193. All latter 142 isolates were subtyped by multilocus variable-number tandem repeat analysis (MLVA). MLVA was also applied to 70 DT193 serologically-defined monophasic variant isolates. Results indicate that serovar 4,[5],12:i:- accounted for 108 of 209 (52%) of DT193 isolates with available serological data and 99 of 142 (70%) monophasic variant isolates belonging to other phage types. Of 609 DT193 isolates, 463 (76%) lacked fljB and hin. Moreover, genetically-related isolates of DTs 120, 191, 191a, 195, phage types U311 and U323, and reacts but does not conform (RDNC) and untypable (UT) strains were also lacking either hin and/or fljB. Of note, the serovar 4,[5],12:i:- DT193-associated genomic island was identified in not only 458 of 463 (99%) monophasic DT193 isolates, but also 25 of 139 (18%) biphasic DT193 isolates and 56 of 76 (74%) monophasic variants of other phage types. Accurate monitoring of the emergence of serovar 4,[5],12:i:- isolates is important to ascertain the public health impact of these strains; since 2012 the Health Protection Agency’s Salmonella Reference Unit has therefore begun determining full antigenic structures of all presumptive O:4 isolates in addition to routinely performing phage typing for identification of variants of serovar Typhimurium.
难以准确鉴定血清型 4,[5],12:i:-为沙门氏菌肠炎血清型鼠伤寒的单相变体，这意味着在报告鼠伤寒血清型和 4,[5],12:i:-时存在混淆。为了深入了解这些单相变体在英格兰和威尔士的流行情况和多样性，对 609 株指定为明确噬菌体型（DT）193 的肠沙门氏菌分离株和 142 株血清学定义为鼠伤寒单相变体但属于非 DT193 噬菌体型的分离株进行了 fljB、hin 和血清型 4,[5],12:i:-相关基因组岛的筛选。所有 142 株后续分离株均通过多位点可变数串联重复分析（MLVA）进行了亚型分型。MLVA 还应用于 70 株血清学定义的 DT193 单相变体分离株。结果表明，血清型 4,[5],12:i:-占具有可用血清学数据的 209 株 DT193 分离株中的 108 株（52%）和属于其他噬菌体型的 142 株单相变体分离株中的 99 株（70%）。在 609 株 DT193 分离株中，463 株（76%）缺乏 fljB 和 hin。此外，DTs 120、191、191a、195、噬菌体型 U311 和 U323 以及反应但不相符（RDNC）和无法定型（UT）菌株的遗传相关分离株也缺乏 hin 和/或 fljB。值得注意的是，不仅在 463 株单相 DT193 分离株中的 458 株（99%），而且在 139 株双相 DT193 分离株中的 25 株（18%）和 76 株单相变体的其他噬菌体型中的 56 株（74%）中均发现了血清型 4,[5],12:i:-DT193 相关基因组岛。准确监测血清型 4,[5],12:i:-分离株的出现对于确定这些菌株对公共卫生的影响非常重要；自 2012 年以来，英国卫生保护局的沙门氏菌参考单位因此已开始确定所有推定的 O:4 分离株的完整抗原结构，除了常规进行噬菌体分型以鉴定鼠伤寒血清型变体之外。
