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出处:The Lancet Infectious Diseases, Early Online Publication, 7 April 2011
Title: Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study
Author: Timothy R Walsh,Janis Weeks,David M Livermore,]Mark A Toleman Abstract: BackgroundNot all patients infected with NDM-1-positive bacteria have a history of hospital admission in India, and extended-spectrum β-lactamases are known to be circulating in the Indian community. We therefore measured the prevalence of the NDM-1 gene in drinking water and seepage samples in New Delhi.
MethodsSwabs absorbing about 100 μL of seepage water (ie, water pools in streets or rivulets) and 15 mL samples of public tap water were collected from sites within a 12 km radius of central New Delhi, with each site photographed and documented. Samples were transported to the UK and tested for the presence of the NDM-1 gene, blaNDM-1, by PCR and DNA probing. As a control group, 100 μL sewage effluent samples were taken from the Cardiff Wastewater Treatment Works, Tremorfa, Wales. Bacteria from all samples were recovered and examined for blaNDM-1 by PCR and sequencing. We identified NDM-1-positive isolates, undertook susceptibility testing, and, where appropriate, typed the isolates. We undertook Inc typing on blaNDM-1-positive plasmids. Transconjugants were created to assess plasmid transfer frequency and its relation to temperature.
FindingsFrom Sept 26 to Oct 10, 2010, 171 seepage samples and 50 tap water samples from New Delhi and 70 sewage effluent samples from Cardiff Wastewater Treatment Works were collected. We detected blaNDM-1 in two of 50 drinking-water samples and 51 of 171 seepage samples from New Delhi; the gene was not found in any sample from Cardiff. Bacteria with blaNDM-1 were grown from 12 of 171 seepage samples and two of 50 water samples, and included 11 species in which NDM-1 has not previously been reported, including Shigella boydii and Vibrio cholerae. Carriage by enterobacteria, aeromonads, and V cholera was stable, generally transmissible, and associated with resistance patterns typical for NDM-1; carriage by non-fermenters was unstable in many cases and not associated with typical resistance. 20 strains of bacteria were found in the samples, 12 of which carried blaNDM-1 on plasmids, which ranged in size from 140 to 400 kb. Isolates of Aeromonas caviae and V cholerae carried blaNDM-1 on chromosomes. Conjugative transfer was more common at 30°C than at 25°C or 37°C.
InterpretationThe presence of NDM-1 β-lactamase-producing bacteria in environmental samples in New Delhi has important implications for people living in the city who are reliant on public water and sanitation facilities. International surveillance of resistance, incorporating environmental sampling as well as examination of clinical isolates, needs to be established as a priority.
FundingEuropean Union.
感染NDM-1的病人,并非都有入院史。在柳叶刀新发表的这篇研究中,他们再新德里地区水源中和渗流样本中,发现了NDM-1的存在,有些(11个新型NDM-1)以前尚未报道。耐药基因 bla-I也在霍乱弧菌和气单胞菌中携带。
suggestion (personal view):
环境中NDM-1的定植并能存活一定的时间,提示:与“HA-MRSA的感染进展到CA-MRSA”类似,NDM-1的感染也可能发展至社区获得性感染,而可能导致暴发的发生。加强环境监测是一个重要的预防举措,包括饮用水和卫生设施物体表面病原监测。超级细菌感染已经成为一个全球关注的公共卫生为题,提示,预防暴发要求国家层面的监测合作,包括环境监测和临床分离物的监测。 |