Bialkowska-Hobrzanska H, Jaskot D, Hammerberg O
Department of Microbiology and Infectious Diseases, St. Joseph's Health Centre, London, Ontario, Canada.
J Clin Microbiol. 1990 Feb;28(2):269-75. doi: 10.1128/jcm.28.2.269-275.1990.
A procedure was developed for restriction endonuclease fingerprinting (REF) of the chromosomal DNA of coagulase-negative staphylococci. A total of 48 isolates comprising 29 Staphylococcus epidermidis and 19 Staphylococcus haemolyticus isolates from blood and mucocutaneous sites of 15 premature neonates were characterized by REF, plasmid profile (PP) analysis, antimicrobial susceptibility testing, biotyping, and slime production. On the basis of REF analysis of chromosomal DNA, the 48 coagulase-negative staphylococcal isolates were subdivided into 10 subgroups, whereas PP analysis subdivided the strains into 20 distinct subgroups. REF analysis of total DNA (i.e., chromosome plus plasmid) resulted in the same 20 subgroups as were subdivided by PP analysis. The high discriminatory power of PP analysis was associated with the variability of plasmid content in coagulase-negative staphylococcal strains isolated during the outbreak. REF patterns were found to be stable both in vitro and in vivo. Isolates carried from 2 to 10 plasmids that ranged in molecular size from 0.9 to 39.5 megadaltons. Plasmids were disseminated among the coagulase-negative staphylococci, regardless of the genetic relatedness of their chromosomal DNAs. Hence, a lack of correlation existed between the grouping of isolates by REF analysis of chromosomal DNA and the grouping by PP analysis. There were one and two distinct chromosomal patterns among 4 of 4 blood cultures and 15 of 15 mucocutaneous cultures of S. haemolyticus, respectively. In contrast, a higher proportion of distinct chromosomal patterns was found for S. epidermidis in blood cultures (7 of 11 cultures) compared with those identified for isolates in mucocutaneous cultures (6 of 18 cultures). In summary, REF analysis of chromosomal DNA, rather than total DNA, is a useful marker for epidemiological investigations of coagulase-negative staphylococci. PP analysis can also be used to provide additional epidemiological information regarding the most recent genetic events.
已开发出一种用于凝固酶阴性葡萄球菌染色体DNA的限制性内切酶指纹图谱（REF）分析的方法。从15例早产儿的血液和黏膜皮肤部位分离出48株菌株，其中包括29株表皮葡萄球菌和19株溶血葡萄球菌，通过REF分析、质粒图谱（PP）分析、抗菌药敏试验、生物分型和黏液产生情况对这些菌株进行了鉴定。基于染色体DNA的REF分析，48株凝固酶阴性葡萄球菌分离株被细分为10个亚组，而PP分析则将这些菌株细分为20个不同的亚组。对总DNA（即染色体加质粒）的REF分析产生了与PP分析细分出的相同的20个亚组。PP分析的高鉴别力与暴发期间分离出的凝固酶阴性葡萄球菌菌株中质粒含量的变异性有关。发现REF图谱在体外和体内均稳定。分离株携带2至10个质粒，分子大小在0.9至39.5兆道尔顿之间。质粒在凝固酶阴性葡萄球菌之间传播，无论其染色体DNA的遗传相关性如何。因此，通过染色体DNA的REF分析对分离株进行分组与通过PP分析进行分组之间缺乏相关性。溶血葡萄球菌的4份血培养物中有4份以及15份黏膜皮肤培养物中有15份分别有1种和2种不同的染色体模式。相比之下，表皮葡萄球菌在血培养物中（11份培养物中有7份）发现的不同染色体模式比例高于在黏膜皮肤培养物中分离株所鉴定出的比例（18份培养物中有6份）。总之，对染色体DNA而非总DNA进行REF分析是凝固酶阴性葡萄球菌流行病学调查的有用标志物。PP分析也可用于提供有关最新遗传事件的额外流行病学信息。
