Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci
Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci
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DOI：
10.1093/jac/dki492
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发表时间：
2006-03-01
影响因子：
5.2
通讯作者：
Aarestrup, FM
中科院分区：
文献类型：
--
作者：
Olsen, JE;Christensen, H;Aarestrup, FM
目的：阐明质粒和染色体定位的blaZ的多样性和进化历史，检测blaZ在人类和牛葡萄球菌之间频繁交换的迹象，并估计blaZ在凝固酶阴性葡萄球菌（CoNS）和牛源金黄色葡萄球菌之间转移的频率。方法：对来自丹麦5个牛群的143株耐青霉素金黄色葡萄球菌和con （n = 25/23）、丹麦随机分离的con （n = 37）、6个不同国家收集的金黄色葡萄球菌（n = 52）、丹麦人（n = 3）和β -内酰胺酶对照菌株（n = 3）进行blaZ检测。在105个菌株中确定了该序列，并通过双比对和多重比对与已发表的序列进行比较。进行极大似然分析，包括自举分析。对重组进行了节俭、邻居加入和共识比较。采用Southern印迹法对108株菌株进行了blaZ定位鉴定。结果：所有耐青霉素菌株均携带blaZ， blaR1与blaZ组织结构相似。blaZ基因仅在16个耐药菌株的质粒上定位。105株69条序列与公共数据库检索的序列进行了比较。系统发育树显示，blaZ存在于3个进化系中：一个是质粒起源的进化系，一个是染色体起源的进化系，一个是中间进化系。共发现69种序列类型。它们被翻译成11种BlaZ蛋白。主要类型均含有人类和牛源菌株，以及不止一种葡萄球菌，表明共享基因库。在比较从丹麦5个牛群中获得的金黄色葡萄球菌和con时，同一类型的blaZ仅在1例中检测到。结论：结果表明质粒编码和染色体编码blaZ的进化是分开的。虽然葡萄球菌之间似乎存在一个共同的基因库，但菌株和物种之间的blaZ交换被认为是极其罕见的事件。
Objectives: To elucidate the diversity and evolutionary history of plasmid- and chromosomally-located blaZ, to detect indications of frequent exchange of blaZ between human and bovine staphylococci and to estimate the frequency of transfer of blaZ between coagulase-negative staphylococci (CoNS) and Staphylococcus aureus of bovine origin.Methods: blaZ was detected in 143 strains of penicillin-resistant S. aureus and CoNS from five Danish cattle herds (n = 25/23), random CoNS isolates from Denmark (n = 37), a collection of S. aureus from six different countries (n = 52), humans in Denmark (n = 3) and beta-lactamase control strains (n = 3). The sequence was determined in 105 strains and compared to published sequences by pairwise and multiple alignments. Maximum likelihood analysis was performed including bootstrap analysis. Parsimony, neighbour joining and consensus comparisons were performed for recombination. The localization of blaZ was determined by Southern blotting in 108 isolates.Results: All penicillin-resistant strains carried blaZ and showed a similar organization of blaR1 and blaZ. The blaZ gene was localized to a plasmid in only 16 of the resistant strains. Sixty-nine sequences representing 105 isolates and sequences retrieved from public databases were compared. A phylogenetic tree showed that blaZ exists in three evolutionary lines: one group was of plasmid origin, one group was of chromosomal origin and one intermediate group. Sixty-nine sequence types were demonstrated. They translated into 11 BlaZ protein types. The major types all contained strains of both human and bovine origin, and more than one Staphylococcus species, demonstrating a shared gene pool. In a comparison of S. aureus and CoNS obtained from five Danish cattle herds, the same type of blaZ was only detected in one case.Conclusions: Results indicated a separate evolution for plasmid- and chromosomally-encoded blaZ. Although a common gene pool seems to exist among staphylococci, exchange of blaZ between strains and species is judged to be an extremely rare event.