Smeltzer M S, Pratt F L, Gillaspy A F, Young L A
Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA.
J Clin Microbiol. 1996 Jun;34(6):1364-72. doi: 10.1128/jcm.34.6.1364-1372.1996.
We used genomic fingerprinting to investigate an outbreak of methicillin-resistant Staphylococcus aureus in the neonatal intensive care units (NICUs) of two hospitals. The hospitals are located in the same city and are part of the same medical care system. Fingerprinting was done by Southern blot hybridization with DNA probes for the genes encoding the S. aureus collagen adhesin (cna), fibronectin-binding proteins (fnbA and fnbB), and beta-toxin (hlb). Genomic DNA was digested with HaeIII (cna and fnbA-fnbB probes) or HindIII (hlb probe). Hybridization patterns could be distinguished on the basis of (i) the presence or absence of cna, (ii) the size of the restriction fragment containing the cna gene, (iii) restriction fragment length polymorphisms within fnbA and fnbB, (iv) the presence of a lysogenic phage within hlb, and (v) the sizes of the restriction fragments containing the phage-bacterial DNA junction fragments. Over a period of 4 months we examined a total of 46 isolates obtained from various wards within each hospital. Among these 46 isolates, we observed a total of 4 cna patterns, 11 fnbA-fnbB patterns, and 11 hlb patterns. Southern blots with HaeIII-digested genomic DNA and a combination of all three gene probes revealed a total of 16 clearly distinguishable patterns. A total of 22 of the 46 isolates were identical with respect to every genomic marker examined. A total of 21 of these 22 isolates were obtained from patients within an NICU. Nineteen of 21 isolates also exhibited identical antibiotic resistance profiles (antibiogram). Although 5 of the remaining 24 strains exhibited an antibiogram identical to those of the NICU isolates, all 24 strains could be distinguished from the NICU isolates by at least one genomic marker. These results suggest that the NICU isolates had a common origin and that genomic fingerprinting with the cna, fnbA, fnbB, and hlb gene probes can provide an important epidemiological tool for the identification of clinical isolates of S. aureus.
我们运用基因组指纹图谱技术，对两家医院新生儿重症监护病房（NICUs）中耐甲氧西林金黄色葡萄球菌的暴发情况展开调查。这两家医院位于同一城市，且隶属于同一医疗体系。通过用编码金黄色葡萄球菌胶原黏附素（cna）、纤连蛋白结合蛋白（fnbA和fnbB）以及β-毒素（hlb）的基因的DNA探针进行Southern印迹杂交来完成指纹图谱分析。基因组DNA用HaeIII（用于cna和fnbA - fnbB探针）或HindIII（用于hlb探针）进行消化。杂交模式可依据以下几点来区分：（i）cna的有无；（ii）包含cna基因的限制性片段的大小；（iii）fnbA和fnbB内的限制性片段长度多态性；（iv）hlb内溶原性噬菌体的存在情况；（v）包含噬菌体 - 细菌DNA连接片段的限制性片段的大小。在4个月的时间里，我们总共检测了从每家医院各个病房分离得到的46株菌株。在这46株菌株中，我们总共观察到4种cna模式、11种fnbA - fnbB模式和11种hlb模式。用HaeIII消化的基因组DNA以及所有三种基因探针的组合进行Southern印迹分析，总共揭示出16种清晰可辨的模式。46株菌株中有22株在检测的每个基因组标记方面都完全相同。这22株菌株中有21株是从新生儿重症监护病房的患者中分离得到的。21株菌株中的19株还表现出相同的抗生素耐药谱（抗菌谱）。尽管其余24株菌株中有5株的抗菌谱与新生儿重症监护病房分离株的抗菌谱相同，但所有24株菌株至少可通过一个基因组标记与新生儿重症监护病房分离株区分开来。这些结果表明，新生儿重症监护病房分离株有共同的起源，并且用cna、fnbA、fnbB和hlb基因探针进行基因组指纹图谱分析可为鉴定金黄色葡萄球菌临床分离株提供一种重要的流行病学工具。
