Jursa-Kulesza Joanna, Kordek Agnieszka, Kopron Katarzyna, Wojciuk Bartosz, Giedrys-Kalemba Stefania
Department of Microbiology and Immunology, Pomeranian Medical University, ul. Powstancow Wlkp. 72 Szczecin PL-70-111, Poland.
Neonatology. 2009;96(1):61-8. doi: 10.1159/000204961. Epub 2009 Mar 2.
Carriers of Staphylococcus aureus strains can be the source of epidemic infection for patients.
A molecular epidemiological analysis of an impetigo bullosa outbreak in a neonatal ward was performed in order to determine a potential source of the infection and possible routes of subsequent spreading of the epidemic strain.
The genetic relatedness of S. aureus strains isolated from 6 neonates with epidermal lesions and from 21 staff members was verified by the pulsed field gel electrophoresis (PFGE) method. Additionally, detection of eta and etb genes of S. aureus strains using PCR was performed.
None of the infected newborns' mothers was a carrier. Seven strains, 6 isolated from the newborns and 1 taken from a midwife, showed the same restriction pattern, i.e. type A. In the other 20 health care workers colonized with S. aureus, 3 genetic types could be distinguished, i.e. B (2), C (7) and D (2), as well as 9 strains with unique PFGE patterns. The eta gene detected in 7 strains belonged to the genetic type A; there was no etb gene in any of the 27 S. aureus isolates.
The presence of the same genetic type A of S. aureus in the infected newborns is a factor which indicates that the impetigo bullosa was a hospital infection. A probable source of the infection was a midwife who was colonized with the same S. aureus type. She was present at the birth of the first infected newborn. Today, molecular methods are essential for prompt recognition of an epidemic and implementation of appropriate infection control strategies.
金黄色葡萄球菌菌株携带者可能是患者感染流行的源头。
对新生儿病房大疱性脓疱病暴发进行分子流行病学分析，以确定感染的潜在来源及流行菌株后续传播的可能途径。
采用脉冲场凝胶电泳（PFGE）法验证从6例有表皮病变的新生儿及21名医护人员分离出的金黄色葡萄球菌菌株的遗传相关性。此外，还采用聚合酶链反应（PCR）检测金黄色葡萄球菌菌株的eta和etb基因。
感染新生儿的母亲均非携带者。7株菌株，6株从新生儿中分离得到，1株从一名助产士处分离得到，显示出相同的限制性图谱，即A型。在其他20名携带金黄色葡萄球菌的医护人员中，可区分出3种遗传类型，即B型（2株）、C型（7株）和D型（2株），以及9株具有独特PFGE图谱的菌株。在7株菌株中检测到的eta基因属于遗传类型A；27株金黄色葡萄球菌分离株中均未检测到etb基因。
感染新生儿中存在相同遗传类型A的金黄色葡萄球菌这一因素表明大疱性脓疱病是医院感染。感染的可能来源是一名携带相同类型金黄色葡萄球菌的助产士。她在首例感染新生儿出生时在场。如今，分子方法对于迅速识别疫情及实施适当的感染控制策略至关重要。
