巴西一家大学医院新生儿病房新生儿凝固酶阴性葡萄球菌感染的危险因素
Risk factors for infection with coagulase-negative staphylococci in newborns from the neonatal unit of a brazilian university hospital.
作者信息
de Oliveira Adilson, Sanches Patrícia, Lyra João C, Bentlin Maria R, Rugolo Ligia M S S, de Lourdes Ribeiro de Souza da Cunha Maria
机构信息
Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil.
出版信息
Clin Med Insights Pediatr. 2011 Dec 15;6:1-9. doi: 10.4137/CMPed.S7427. Print 2012.
BACKGROUND
Coagulase-negative staphylococci (CoNS) are one of the most frequent causative agents of neonatal nosocomial infections, especially in premature and low-weight newborns. Risk factors for infection include extracellular polysaccharide production and consequent biofilm formation that permit adhesion to the smooth surface of catheters and other medical devices. The objective of this study was to identify CoNS strains isolated from 105 newborns admitted to the Neonatal Unit of our hospital, and to evaluate the association of biofilm production and host risk factors with the occurrence of infection.
METHODS
CoNS isolates were identified and classified as significant or contaminant based on clinical and laboratory data of the newborn medical records. Perinatal risk factors for infection, neonatal clinical evolution, and antibiotic treatment were analysed. In addition, the presence of genes (icaA, icaC and icaD) responsible for biofilm production in CoNS was investigated.
RESULTS
Among the 130 CoNS strains studied, 66 (50.8%) were classified as clinically significant and 64 (49.2%) as contaminant. There was no difference in the detection of biofilm-specific genes between CoNS strains isolated from newborns with (81.8%) and without infection (84.3%), although 11 (91.7%) of the 12 children whose death was related to CoNS were infected with strains that were positive for these genes. Forty-five (83.3%) of the 54 newborns infected with CoNS were premature and 33 (61.1%) had a birth weight ≤ 1,500 g. Most newborns infected with CoNS had been submitted to invasive procedures, including catheter use (85.2%), parenteral nutrition (61.1%), and mechanical ventilation (57.4%). S. epidermidis was the most frequently isolated species (81.5%) and was more related to infection (86.3%) than to contamination (76.5%).
CONCLUSION
Most newborns infected with CoNS presented factors that contributed to the colonization and development of infection with these microorganisms, including a birth weight ≤ 1,500 g, catheter complications, use of a drain, and previous antibiotic treatment. The fact that most children who died of CoNS-related infection carried strains positive for biofilm-specific genes indicates the importance of this virulence factor for the outcome of staphylococcal infections.
背景
凝固酶阴性葡萄球菌（CoNS）是新生儿医院感染最常见的病原体之一，尤其是在早产儿和低体重新生儿中。感染的危险因素包括细胞外多糖的产生以及随之而来的生物膜形成，这使得细菌能够粘附在导管和其他医疗设备的光滑表面上。本研究的目的是鉴定从我院新生儿病房收治的105例新生儿中分离出的CoNS菌株，并评估生物膜产生和宿主危险因素与感染发生之间的关联。
方法
根据新生儿病历的临床和实验室数据，对CoNS分离株进行鉴定，并分为有意义或污染性菌株。分析围产期感染危险因素、新生儿临床病程及抗生素治疗情况。此外，还研究了CoNS中负责生物膜产生的基因（icaA、icaC和icaD）的存在情况。
结果
在研究的130株CoNS菌株中，66株（50.8%）被分类为临床有意义菌株，64株（49.2%）为污染性菌株。从感染（81.8%）和未感染（84.3%）新生儿中分离出的CoNS菌株在生物膜特异性基因检测方面没有差异，尽管12例与CoNS相关死亡儿童中有11例（91.7%）感染了这些基因呈阳性的菌株。54例感染CoNS的新生儿中有45例（83.3%）为早产儿，33例（61.1%）出生体重≤1500g。大多数感染CoNS的新生儿接受过侵入性操作，包括使用导管（85.2%）、肠外营养（61.1%）和机械通气（57.4%）。表皮葡萄球菌是最常分离出的菌种（81.5%），与感染（86.3%）的相关性高于污染（76.5%）。
结论
大多数感染CoNS的新生儿存在促使这些微生物定植和感染发展的因素，包括出生体重≤1500g、导管并发症、引流管使用和先前的抗生素治疗。大多数死于CoNS相关感染的儿童携带生物膜特异性基因阳性菌株这一事实表明，这种毒力因子对葡萄球菌感染的结局具有重要意义。
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