超級(jí)細(xì)菌的暴發(fā)困擾著英國劍橋市新生兒特殊護(hù)理病房的醫(yī)護(hù)人員,。在基因測(cè)序的幫助下,，去年以來持續(xù)數(shù)月的困境終于結(jié)束了,?？窃诮诔霭娴摹读~刀—傳染病》上的一份研究報(bào)告稱,，科學(xué)家首次測(cè)序了病原體基因，以便積極控制進(jìn)行中的超級(jí)細(xì)菌暴發(fā),。
英國劍橋大學(xué)的臨床微生物學(xué)家Sharon Peacock及其同事被卷入了這場超級(jí)細(xì)菌暴發(fā)的困境中,。當(dāng)時(shí)，幾天內(nèi),，當(dāng)?shù)氐牧_西醫(yī)院嬰兒24小時(shí)特別監(jiān)護(hù)室中的三個(gè)嬰兒的耐甲氧西林金黃色葡萄球菌（MRSA）測(cè)試相繼呈陽性,。
從這三個(gè)嬰兒身上分離出的細(xì)菌對(duì)一類抗生素表現(xiàn)出耐藥性,，研究人員表示,，這指向一個(gè)公共細(xì)菌源,。病房被徹底地清掃干凈,，醫(yī)護(hù)人員希望超級(jí)細(xì)菌噩夢(mèng)能夠就此結(jié)束。
不過,，出于科學(xué)家的好奇心,，Peacock研究小組繼續(xù)調(diào)查了這三個(gè)病例是否與之前的半年里羅西醫(yī)院出現(xiàn)的一系列MRSA感染有聯(lián)系,。
實(shí)驗(yàn)室測(cè)試結(jié)果顯示,，那時(shí)至少還有另外8名兒童感染了相似耐藥性的MRSA菌株。但是,，有數(shù)周沒有出現(xiàn)感染病例,，這又顯示超級(jí)細(xì)菌的感染并不是簡單地從該病房的嬰兒傳染到嬰兒,。
為了將一連串事件串聯(lián)起來，Peacock研究小組開始對(duì)取自該醫(yī)院的這種MRSA菌株以及收集自其他醫(yī)院的成年患者的相似的菌株的基因進(jìn)行測(cè)序,?；蚪M測(cè)序結(jié)果顯示,，嬰兒病房的菌株與其他疑似病例的菌株相吻合,。
不過,，羅西醫(yī)院的細(xì)菌暴發(fā)并沒有結(jié)束,。該病房殺菌數(shù)天后,，又有一個(gè)嬰兒的MRSA檢測(cè)結(jié)果呈陽性,。
不斷的MRSA傳染,，讓Peacock和羅西醫(yī)院流行病學(xué)家們?nèi)缗R大敵,。確定暴發(fā)菌株基因序列后，他們開始從嬰兒病房的154個(gè)工作人員中尋找暴發(fā)的菌株,。其中一人的相關(guān)檢測(cè)結(jié)果呈陽性,，盡管還沒有出現(xiàn)任何癥狀。
“我們將會(huì)將這個(gè)人隔離出感染鏈,，以便有效地預(yù)防持續(xù)暴發(fā),。” Peacock說,。
進(jìn)一步的監(jiān)查還在這些成年人之中發(fā)現(xiàn)了另外的傳染病，這些人還包括從自己孩子身上接觸過MRSA的父母,。一共有14個(gè)患者——6個(gè)嬰兒和8個(gè)成人——出現(xiàn)嚴(yán)重感染,，亟須治療。最后一個(gè)確診案例發(fā)生在大暴發(fā)一年之后,，病人是一位父親,，他從配偶那里接觸了MRSA。值得慶幸的是,，沒有人死亡,。
這里，基因測(cè)序提供了明晰的線索,，這是其他方法難以做到的,，該論文的合作者、英國維康信托基金會(huì)桑格研究所微生物學(xué)家Julian Parkhill表示,。
基因測(cè)序能夠揭示細(xì)菌暴發(fā)過程中發(fā)生的一系列小規(guī)模的基因突變,，幫助流行病學(xué)家編寫一個(gè)進(jìn)化樹,，并追蹤暴發(fā)的源頭。進(jìn)化分析顯示,，這名受感染的雇員很可能是從該病房的一個(gè)患病嬰兒那里感染了MRSA,。(生物谷Bioon.com)
doi:10.1016/S1473-3099(12)70268-2
PMC:
PMID:
Whole-genome sequencing for analysis of an outbreak of meticillin-resistant Staphylococcus aureus: a descriptive study
Simon R Harris PhD, Edward JP Cartwright MBBS, M Estée T?r?k FRCP, Matthew TG Holden PhD, Nicholas M Brown MD, Amanda L Ogilvy-Stuart FRCP, Matthew J Ellington DPhil, Michael A Quail PhD, Stephen D Bentley PhD, Prof Julian Parkhill PhD, Prof Sharon J Peacock FRCP
Background
The emergence of meticillin-resistant Staphylococcus aureus (MRSA) that can persist in the community and replace existing hospital-adapted lineages of MRSA means that it is necessary to understand transmission dynamics in terms of hospitals and the community as one entity. We assessed the use of whole-genome sequencing to enhance detection of MRSA transmission between these settings.
Methods
We studied a putative MRSA outbreak on a special care baby unit (SCBU) at a National Health Service Foundation Trust in Cambridge, UK. We used whole-genome sequencing to validate and expand findings from an infection-control team who assessed the outbreak through conventional analysis of epidemiological data and antibiogram profiles. We sequenced isolates from all colonised patients in the SCBU, and sequenced MRSA isolates from patients in the hospital or community with the same antibiotic susceptibility profile as the outbreak strain.
Findings
The hospital infection-control team identified 12 infants colonised with MRSA in a 6 month period in 2011, who were suspected of being linked, but a persistent outbreak could not be confirmed with conventional methods. With whole-genome sequencing, we identified 26 related cases of MRSA carriage, and showed transmission occurred within the SCBU, between mothers on a postnatal ward, and in the community. The outbreak MRSA type was a new sequence type (ST) 2371, which is closely related to ST22, but contains genes encoding Panton-Valentine leucocidin. Whole-genome sequencing data were used to propose and confirm that MRSA carriage by a staff member had allowed the outbreak to persist during periods without known infection on the SCBU and after a deep clean.
Interpretation
Whole-genome sequencing holds great promise for rapid, accurate, and comprehensive identification of bacterial transmission pathways in hospital and community settings, with concomitant reductions in infections, morbidity, and costs.
Funding
UK Clinical Research Collaboration Translational Infection Research Initiative, Wellcome Trust, Health Protection Agency, and the National Institute for Health Research Cambridge Biomedical Research Centre.
