ABSTRACT
Objective To study on the contribution and cut-off value of coagulase negative staphylococcus (CoNS) in laboratory tests of postoperative infection in neurosurgery and optimize the diagnostic criteria of infection.Methods It made a retrospective study of 650 cerebrospinal fluid (CSF)specimens from neurosurgical patients,who were infected CoNS in Beijing Tiantan Hospital affiliated to Capital Medical University during 2013-2015.The epidemiological data were collected and 8 routine clinical laboratory tests were performed.T test was used to compare the difference among the groups.By making receiver operating characteristic (ROC) curve,the area under the curve (AUC),cut-off value,sensitivity and specificity were obtained.Results A total of 19 756 CSF specimens were collected and 650 CoNS were isolated.The separation rate of CoNS was 3.3% which was the most frequently isolated bacteria.The differences of cerebrospinal fluid white blood cell count (3 598.6 ± 1 884.3,678.1 ± 629.1,t =2.662,P =0.012),multinucleated cell ratio in cerebrospinal fluid(76.0 ±32.6,46.8 ±29.9,t =9.593,P =0.001),cerebrospinal fluid glucose concentration (5.9 ± 2.12,6.2 ± 1.92,t =-16.296,P =0.001) and cerebrospinal fluid glucose concentration/blood glucose concentration (0.3 ± 0.16,0.63 ± 0.31,t =-11.968,P =0.000) among groups were statistically significant.The AUCs of cerebrospinal fluid white blood cell count,cerebrospinal fluid glucose and cerebrospinal fluid glucose/blood glucose were more than 0.8,and the sensitivities of the three indicators were more than 80.0%.In addition,the specificity of cerebrospinal fluid glucose concentration/blood glucose concentration was more than 0.9.Conclusions CoNS was the main pathogenic bacteria of neurosurgical infections in a hospital.Cerebrospinal fluid white blood cell count,cerebrospinal fluid glucose and the ratio of cerebrospinal fluid glucose and blood glucose could be used for auxiliary diagnosis of CoNS infections in neurosurgical patients.