García-Vázquez Elisa, Fernández-Rufete Ana, Hernández-Torres Alicia, Canteras Manuel, Ruiz Joaquín, Gómez Joaquín
Servicio de MI-Infecciosas, Hospital Clínico Universitario Virgen de la Arrixaca, Madrid-Cartagena, El Palmar, Murcia, Spain.
Scand J Infect Dis. 2013 Sep;45(9):664-71. doi: 10.3109/00365548.2013.797599. Epub 2013 Jul 1.
Coagulase-negative staphylococci (CoNS) are common contaminants in blood cultures (BC). A prospective study of patients with ≥ 2 blood culture sets and at least 1 positive CoNS BC was performed to develop an algorithm to assist in determining the clinical significance of CoNS bacteraemia.
A single reviewer examined the medical records of patients with CoNS bacteraemia (January-June 2010). The determination of clinical significance was made according to CDC/NHSN (US Centers for Disease Control and Prevention/National Healthcare Safety Network) criteria. To explore risk factors associated with clinical significance, a multivariate analysis was performed. The performances of various algorithms were then compared. An algorithm to assist in determining clinical significance was developed.
Two hundred and sixty-nine cases were included; 97 (36%) were considered clinically significant bacteraemia (CSB). Predictors of CSB in the multivariate analysis were: time to positivity < 16 h (odds ratio (OR) 4.540, 95% confidence interval (CI) 1.734-11.884), identification of Staphylococcus epidermidis (OR 4.273, 95% CI 2.124-5.593), central venous catheter (OR 4.932, 95% CI 2.467-9.858), > 2 CoNS-positive bottles from different BC sets (OR 1.957, 95% CI 1.401-2.733), and Charlson score ≥ 3 (OR 2.102, 95% CI 1.078-4.099). The algorithm with best sensitivity (62%) and specificity (93%) for determining clinical significance of CoNS included Charlson score ≥ 3, Pitt score ≥ 1, neutropenic patients, presence of central venous catheter, identification of S. epidermidis, and time to positivity < 16 h. The positive predictive value was 83% and the negative predictive value was 81% (likelihood ratio 8.87).
The use of this algorithm could potentially reduce the misclassification of nosocomial bloodstream infections and inappropriate antibiotic treatment in patients for whom a positive CoNS does not represent a CSB.
凝固酶阴性葡萄球菌（CoNS）是血培养（BC）中常见的污染物。对有≥2套血培养且至少1套CoNS血培养阳性的患者进行了一项前瞻性研究，以开发一种算法来协助确定CoNS菌血症的临床意义。
由一位审阅者检查CoNS菌血症患者（2010年1月至6月）的病历。根据美国疾病控制与预防中心/国家医疗安全网络（CDC/NHSN）标准确定临床意义。为探索与临床意义相关的危险因素，进行了多变量分析。然后比较了各种算法的性能。开发了一种协助确定临床意义的算法。
纳入269例病例；97例（36%）被认为是具有临床意义的菌血症（CSB）。多变量分析中CSB的预测因素为：阳性时间<16小时（比值比（OR）4.540，95%置信区间（CI）1.734 - 11.884）、表皮葡萄球菌的鉴定（OR 4.273，95%CI 2.124 - 5.593）、中心静脉导管（OR 4.932，95%CI 2.467 - 9.858）、来自不同血培养套数的>2瓶CoNS阳性瓶（OR 1.957，95%CI 1.401 - 2.733）以及Charlson评分≥3（OR 2.102，95%CI 1.078 - 4.099）。用于确定CoNS临床意义的最佳敏感性（62%）和特异性（93%）的算法包括Charlson评分≥3、Pitt评分≥1、中性粒细胞减少患者、存在中心静脉导管、表皮葡萄球菌的鉴定以及阳性时间<16小时。阳性预测值为83%，阴性预测值为81%（似然比8.87）。
使用该算法可能会减少CoNS阳性但不代表CSB的患者医院血流感染的错误分类和不适当的抗生素治疗。
