摘要目的 分析凝固酶阴性葡萄球菌(coagulase-negative Staphylococci,CNS)血流感染的临床特征及药敏情况,为临床诊断和治疗提供依据.方法 对华中科技大学同济医学院附属普爱医院2016年1月至2017年12月收集的108例血培养CNS阳性的住院患者进行回顾性分析,采用纸片扩散法(K-B法)和Etest法进行抗菌药物敏感性试验.正态分布计量资料采用t检验,非正态分布资料采用秩和检验,计数资料采用x2检验.结果 108例患者中男66例,女42例,年龄范围26～98岁,平均49.0岁.根据菌血症的判断标准,36例(33.3％)患者确诊为菌血症,血样污染72例(66.7％).CNS菌血症主要分布在ICU、肾病内科.其中23例(62.2％)患者为导管相关血流感染(catheter-related bloodstream infections,CRBSI),11例(29.7％)患者为透析置管相关血流感染.CNS感染发生在人院48 h内的患者占41.7％(15/36).菌血症患者降钙素原(procalcitonin,PCT)为2.56(1.44,7.60) μg/L,血样污染患者为0.13(0.05,0.23) μg/L,比较差异有统计学意义(Z=8.097,P＜0.05).菌血症患者白细胞计数为(11.50±4.54)×109/L,血样污染患者为(10.61±5.00)×109/L,比较差异无统计学意义(t=0.895,P＞0.05).经过抗菌药物治疗后,36例菌血症患者中存活26例,存活患者治疗前PCT为2.05(1.42,4.32) μg/L,治疗后为0.24(0.07,0.61) μg/L,治疗前、后比较差异有统计学意义(Z=4.457,P＜0.05).28 d内死亡的10例患者治疗前PCT为4.78(1.51,19.75) μg/L,治疗后为22(6.40,55.75) μg/L,治疗前、后比较差异有统计学意义(Z=2.497,P＜0.05).28 d内死亡患者PCT与存活患者比较差异无统计学意义(Z=0.300,P＞0.05).28 d内死亡患者白细胞计数与存活患者比较差异无统计学意义(t=0.771,P＞0.05).病原菌与污染菌对抗菌药物的耐药率差异均无统计学意义(均P＞0.05).所有菌株对万古霉素、替考拉宁和利奈唑胺敏感.结论 CNS在血培养阳性患者中的污染比例较高,需结合临床和实验室指标综合判断.PCT对CNS菌血症的诊断和治疗效果监测有一定的临床价值.

abstractsObjective To analyze clinical characteristics of bloodstream infections caused by coagulase-negative Staphylococci (CNS) and antibiotic resistance of the bacteria,so that to provide basis for the clinical diagnosis and treatment.Methods A retrospective analysis of CNS in blood cultures collected from 108 hospitalized patients in Puai Hospital of Tongji Medical College from January 2016 to December 2017 was performed.The antimicrobial susceptibilities were tested by Kirby-Bauer method and E test method.For measurement variables,normally distributed variables were compared using t test,and non-normal distributed data were compared using Mann-Whitney U test.Categorical variables were compared using x2 test.Results Of the 108 patients,66 were male and 42 were female;the age range was 26 to 98 years and the average was 49 years.According to the criteria for bacteremia,36 of 108 (33.3％) patients with CNS-positive blood cultures were diagnosed with bacteremia and 72 (66.7％) cases were contaminated.CNS bacteremia mainly occurred in the intensive care unit and nephropathy ward.Among them,23 (62.2％) patients were catheter-related blood stream infections,and 11 (29.7 ％) patients were dialysis catheter-related bloodstream infections.Fifteen of 36 (41.7％) strains were isolated within 48 hours of admission.The level of serum procalcitonin (PCT) for bacteremia patients was 2.56 (1.44,7.60) μg/L,and that was 0.13 (0.05,0.23) μg/L in contaminated patients.The difference was statistically significant (Z=8.097,P＜0.05).The white blood cell count of patients with bacteremia was (11.50±4.54) × 109/L,and that was (10.61 ±5.00) × 109/L for contaminated patients.There was no statistical significance (t=0.895,P＞0.05).After antibiotic treatment,26 of 36 bacteremia patients were survived.The PCT levels before antibiotic treatment were 2.05 (1.42,4.32) μg/L,and 0.24 (0.07,0.61) μg/L after antibiotic treatment.Serum PCT was decreased significantly after antibiotic treatment (Z=4.457,P＜0.05).The PCT levels of 10 deaths within 28 days before antibiotic treatment were 4.78 (1.51,19.75) μg/L,whereas 22 (6.40,55.75) μg/L,after antibiotic treatment.The PCT was increased significantly after antibiotic treatment (Z=2.497,P＜0.05).No significant difference was found in PCT between survivors and deaths within 28 days (Z=0.300,P＞0.05).No significant difference was found in white blood cell count between survivors and deaths at 28 days (t=0.771,P＞0.05).There was no statistical difference of the anti-bacterial drug susceptibility between pathogens and contaminants (P＞0.05).All strains were sensitive to vancomycin,teicoplanin and linezolid.Conclusions The incidence of CNS contamination in blood culture is relatively high.It is important to distinguish true bacteraemia from contamination by a review of the clinical and laboratory indicators.PCT is of clinical value to indicate CNS infection and to monitor therapeutic effect.