Vallenet David, Nordmann Patrice, Barbe Valérie, Poirel Laurent, Mangenot Sophie, Bataille Elodie, Dossat Carole, Gas Shahinaz, Kreimeyer Annett, Lenoble Patricia, Oztas Sophie, Poulain Julie, Segurens Béatrice, Robert Catherine, Abergel Chantal, Claverie Jean-Michel, Raoult Didier, Médigue Claudine, Weissenbach Jean, Cruveiller Stéphane
Génomique Métabolique, CNRS UMR8030, CEA-Institut de Génomique-Genoscope, Evry, France.
PLoS One. 2008 Mar 19;3(3):e1805. doi: 10.1371/journal.pone.0001805.
Acinetobacter baumannii is the source of numerous nosocomial infections in humans and therefore deserves close attention as multidrug or even pandrug resistant strains are increasingly being identified worldwide. Here we report the comparison of two newly sequenced genomes of A. baumannii. The human isolate A. baumannii AYE is multidrug resistant whereas strain SDF, which was isolated from body lice, is antibiotic susceptible. As reference for comparison in this analysis, the genome of the soil-living bacterium A. baylyi strain ADP1 was used. The most interesting dissimilarities we observed were that i) whereas strain AYE and A. baylyi genomes harbored very few Insertion Sequence elements which could promote expression of downstream genes, strain SDF sequence contains several hundred of them that have played a crucial role in its genome reduction (gene disruptions and simple DNA loss); ii) strain SDF has low catabolic capacities compared to strain AYE. Interestingly, the latter has even higher catabolic capacities than A. baylyi which has already been reported as a very nutritionally versatile organism. This metabolic performance could explain the persistence of A. baumannii nosocomial strains in environments where nutrients are scarce; iii) several processes known to play a key role during host infection (biofilm formation, iron uptake, quorum sensing, virulence factors) were either different or absent, the best example of which is iron uptake. Indeed, strain AYE and A. baylyi use siderophore-based systems to scavenge iron from the environment whereas strain SDF uses an alternate system similar to the Haem Acquisition System (HAS). Taken together, all these observations suggest that the genome contents of the 3 Acinetobacters compared are partly shaped by life in distinct ecological niches: human (and more largely hospital environment), louse, soil.
鲍曼不动杆菌是人类众多医院感染的病原菌，因此值得密切关注，因为全球范围内越来越多地发现了多重耐药甚至泛耐药菌株。在此，我们报告了对两株新测序的鲍曼不动杆菌基因组的比较。人类分离株鲍曼不动杆菌AYE具有多重耐药性，而从体虱中分离出的菌株SDF对抗生素敏感。作为该分析比较的参考，使用了土壤细菌拜氏不动杆菌菌株ADP1的基因组。我们观察到的最有趣的差异在于：i）菌株AYE和拜氏不动杆菌的基因组中含有极少的可促进下游基因表达的插入序列元件，而菌株SDF的序列中含有数百个此类元件，它们在其基因组缩减（基因破坏和简单DNA丢失）中起了关键作用；ii）与菌株AYE相比，菌株SDF的分解代谢能力较低。有趣的是，后者甚至比已被报道为营养非常多样化的拜氏不动杆菌具有更高的分解代谢能力。这种代谢表现可以解释鲍曼不动杆菌医院菌株在营养稀缺环境中的持久性；iii）几个已知在宿主感染过程中起关键作用的过程（生物膜形成、铁摄取、群体感应、毒力因子）要么不同，要么不存在，其中最好的例子是铁摄取。事实上，菌株AYE和拜氏不动杆菌利用基于铁载体的系统从环境中获取铁，而菌株SDF使用一种类似于血红素获取系统（HAS）的替代系统。综上所述，所有这些观察结果表明，所比较的3种不动杆菌的基因组内容部分是由它们在不同生态位中的生活所塑造的：人类（以及更广泛的医院环境）、虱子、土壤。
