Investigation of LA-MRSA in China and the UK

在中国和英国，耐甲氧西林金黄色葡萄球菌（MRSA）仍然是一个重要的问题，可导致危及生命的感染。在中国和英国都发现了一种被称为家畜相关MRSA （LA-MRSA）的MRSA。虽然金黄色葡萄球菌的许多菌株似乎仅限于特定的宿主物种，但LA-MRSA的特点是它们可以在农场动物和人类之间自由跳跃。在农场发现的LA-MRSA储存库对人类健康构成了相当大的威胁，在丹麦和荷兰等国家，人类MRSA感染占很大比例。最近来自中国的报告显示，中国的主要LA-MRSA菌株与欧洲和北美的不同。本研究将确定LA-MRSA在中国的流行情况。利用全基因组测序，将比较在人和动物身上发现的LA-MRSA，以确定这些细菌是否从农场传播给人类，并寻找可能与LA-MRSA在人和动物身上定居的能力有关的基因。将发现LA-MRSA的农场与未发现LA-MRSA的农场进行比较，以调查可能与LA-MRSA存在相关的任何风险因素。LA-MRSA宿主特异性的进一步研究将使用一种称为转座子诱变的技术进行。将在LA-MRSA菌株中建立数千个突变体的文库，并用于鉴定可能在使LA-MRSA避开宿主动物和人的免疫防御方面发挥作用的单个基因。

Both in China and the UK methicillin resistant Staphylococcus aureus (MRSA) remain an important problem that can lead to life threatening infections. A type of MRSA called livestock-associated MRSA (LA-MRSA) has been found both in China and the UK. While many strains of S. aureus seem to be restricted to particular host species, LA-MRSA are characterised by the fact that they freely jump between farm animals and people. The reservoir of LA-MRSA found on farms represents a considerable threat to human health and accounts for a large proportion of human MRSA infections in countries such as Denmark and the Netherlands. Recent reports from China show that the dominant LA-MRSA strains in China are different to those in Europe and North America. This research will determine the prevalence of LA-MRSA in China. Using whole genome sequencing, LA-MRSA found in people and animals will be compared to determine if these bacteria are transmitted from farms to people and also to look for genes that may be associated with the ability of LA-MRSA to colonise both people and animals. Farms where LA-MRSA are found will be compared to farms free of LA-MRSA to investigate any risk factors that may be associated with the presence of LA-MRSA. Further investigations of the host specificity of LA-MRSA will be performed using a technique called transposon mutagenesis. A library of many thousands of mutants will be made in LA-MRSA strains and used to identify individual genes that may play a role in enabling LA-MRSA avoid the immune defences of host animals and people.