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目的探讨细胞间粘附基因(ica)A和icaD在新生儿凝固酶阴性葡萄球菌(CNS)败血症中的诊断意义。方法收集北京儿童医院新生儿病房2001年11月至2003年3月间血培养为CNS的患儿为研究入选病例。通过应用聚合酶链反应(PCR)方法检测icaA及icaD的存在。结果在80例入选患儿中,血培养均分离出CNS。根据新生儿败血症的诊断标准,临床诊断败血症27例(33.8%),其中早产儿7例,足月小样儿2例。在菌种的分布上,表皮葡萄球菌18例(66.7%),溶血葡萄球菌7例(25.9%),人葡萄球菌2例(7.4%)。对90株CNS菌株应用PCR方法检测icaA及icaD,共有8株阳性,均为表皮葡萄球菌,并且icaA和icaD同时阳性。在经PCR扩增后所产生的图谱中,icaA在814bp,icaD在282bp。在ica阳性的8例病例中,临床诊断为败血症7例,一致率为87.5%,在临床排除败血症的53例患儿中,仅有1例ica阳性(1.8%)。ica的阳性预测值为25.9%,阴性预测值为98.1%。结论ica基因PCR检测是临床诊断CNS败血症或导管相关感染的一种潜在的实验室方法。
Objective To investigate the diagnostic significance of the intercellular adhesion genes (ica) A and icaD in neonatal coagulase-negative staphylococcal (CNS) sepsis. Methods Children with CNS in blood culture in neonatal ward of Beijing Children’s Hospital from November 2001 to March 2003 were enrolled in this study. The presence of icaA and icaD was detected by polymerase chain reaction (PCR). Results In 80 infants, CNS were isolated from blood cultures. According to the diagnostic criteria of neonatal sepsis, clinical diagnosis of sepsis in 27 cases (33.8%), of which 7 cases of preterm children, 2 cases of full-term baby. Staphylococcus epidermidis in 18 cases (66.7%), Staphylococcus hemolyticus in 7 cases (25.9%), Staphylococcus aureus in 2 cases (7.4%). 90 strains of CNS strains were detected by PCR method icaA and icaD, a total of 8 strains were positive, were Staphylococcus epidermidis, and icaA and icaD positive at the same time. In the resulting map after PCR amplification, icaA is at 814 bp and icaD is at 282 bp. Of the 8 positive cases in ica, 7 were clinically diagnosed as sepsis with a concordance rate of 87.5%. Only 1 of the 53 clinically excluded sepsis was ica positive (1.8%). The positive predictive value for ica was 25.9% and the negative predictive value was 98.1%. Conclusion ica gene PCR detection is a potential laboratory method for clinically diagnosing CNS sepsis or catheter-related infections.