Kang Huaixing, Xu Xiaomeng, Fu Kaifei, An Xioaping, Mi Zhiqiang, Yin Xiuyun, Peng Fan, Pei Guangqian, Wang Yahui, Huang Yong, Zhang Xianglilan, Zhang Zhiyi, Wang Wei, Zhou Lijun, Chen Jiankui, Tong Yigang
School of Basic Medical Science Central South University, Changsha, 410013, People's Republic of China,
Curr Microbiol. 2015 Jul;71(1):54-61. doi: 10.1007/s00284-015-0818-6. Epub 2015 May 3.
Antibiotic-resistant opportunistic pathogens have become a serious concern in recent decades, as they are increasingly responsible for hospital-acquired infections. Here, we describe quinolone-resistant Delftia sp. strain 670, isolated from the sputum of a patient who died from severe pulmonary infection. The draft genome sequence of this strain was obtained by whole-genome shotgun sequencing, and was subjected to comparative genome analysis. Genome analysis revealed that one critical mutation (Ser83Ile in gyrA) might play a decisive role in quinolone resistance. The genome of Delftia sp. strain 670 contains both type II and type VI secretion systems, which were predicted to contribute to the virulence of the strain. Phylogenetic analysis, assimilation tests, and comparative genome analysis indicated that strain 670 differed from the four known Delftia species, suggesting this strain could represent a novel species. Although the study could not determine the strain 670 as the pathogen led to mortality, our findings also presented the pathogenic potential of Delftia species, and the increasing severity of antibiotic resistance among emerging opportunistic pathogens. The whole genome sequencing and comparative analysis improved our understanding of genome evolution in the genus Delftia, and provides the foundation for further study on drug resistance and virulence of Delftia strains.
近几十年来，耐抗生素的机会致病菌已成为一个严重问题，因为它们越来越多地导致医院获得性感染。在此，我们描述了从一名死于严重肺部感染患者的痰液中分离出的耐喹诺酮类代尔夫特菌属菌株670。该菌株的基因组草图序列通过全基因组鸟枪法测序获得，并进行了比较基因组分析。基因组分析表明，一个关键突变（gyrA基因中的Ser83Ile）可能在喹诺酮耐药性中起决定性作用。代尔夫特菌属菌株670的基因组包含II型和VI型分泌系统，预计这些系统有助于该菌株的毒力。系统发育分析、同化试验和比较基因组分析表明，菌株670与四种已知的代尔夫特菌属物种不同，表明该菌株可能代表一个新物种。尽管该研究无法确定菌株670是导致死亡的病原体，但我们的研究结果也揭示了代尔夫特菌属物种的致病潜力，以及新出现的机会致病菌中抗生素耐药性日益严重的情况。全基因组测序和比较分析提高了我们对代尔夫特菌属基因组进化的理解，并为进一步研究代尔夫特菌属菌株的耐药性和毒力奠定了基础。
