儿科表皮葡萄球菌的临床分布、抗生素敏感性和mecA/icaA/icaD基因研究

Distribution characteristics,antibiotics sensitivity and mecA/icaA/icaD genes of Staphylococcus epidermidis isolated from blood and CSF in children

目的了解儿科表皮葡萄球菌(表葡菌)的临床分布特征、抗生素敏感性和mecA/icaA/icaD基因的携带等情况,为临床表葡菌感染的诊断和治疗提供实验依据。方法儿科临床分离的表葡菌采用VITEK 60全自动微生物分析仪结合GPI卡和GPS卡做常规鉴定和药敏,并进行统计分析;用PCR方法检测mecA、icaA和icaD基因。结果 2010年1月～2011年12月期间,共检出442株表葡菌,主要来自新生儿科110株(24.89%)、消化科72株(16.29%)、ICU 68株(15.38%)和呼吸科58株(13.12%);以血液来源为主(382株,86.43%),检出甲氧西林耐药表葡菌(MRSE 378)株(85.52%),总的β-内酰胺酶阳性率为86.43%。MRSE对抗菌药物敏感率低于甲氧西林敏感表葡菌(MSSE),其差异有统计学显著性(P【0.05)。对MRSE敏感率高的抗生素主要为:利奈唑胺(100%)、万古霉素(100%)、利福平(95.8%)、呋喃妥因(98.7%)、莫西沙星(72.8%)、左氧氟沙星(72%)等,而对MSSE敏感率高的抗生素主要为:利奈唑胺(100%)、万古霉素(100%)、呋喃妥因(100%)、利福平(98.4%)、氨苄西林/舒巴坦(98.4%)、莫西沙星(92.2%)、左氧氟沙星(92.2%)等。mecA、icaA、icaD基因在血培养来源(50株)分别与非血培养来源(23株)和环境皮肤来源(22株)表葡菌中的检出率比较无显著性差异。结论儿科临床分离的表葡菌主要源自血液标本,新生儿科检出率高,以MRSE和耐β-内酰胺酶阳性株为主,未发现耐万古霉素表葡菌表葡菌mecA阳性率极高,icaA和icaD基因阳性率较低。

Objective To investigate distribution characteristics,antibiotic sensitivity and mecA/icaA/icaD status of Staphylococcus epidermidis from pediatric patients,which will assist to appropriately use antibiotic in hospital settings.Methods The GPI and GPS cards for VITEK 60 microbiology analyzer were used for identifying organisms,detecting antibiotic sensitivity.The genes of mecA, icaA and icaD were detected by PCRs.WHONET 5.4 and SPSS13.0 software were employed for statistical analysis in this study.Results A total of 442 nonduplicated Staphylococcus epidermidis strains were collected and identified during January 2010 to December 2011,of which mainly isolated from neonatalogy depattment(110,24.89%),Gastroenterology department(72,16.29%),Intense care unit(68,15.38%) and Respiratory medicine department(58,13.12%),of which mainly isolated from blood(382, 86.43%).Among these strains,Methicillin-resistant Staphylococcus epidermidis(MRSE) accounted for 85.52%,and the proportion ofβ-Lactamase were 86.43%.Except for Vancomycin,Linezolid and Rifampin,the sensitivity rates of MRSE strains to Clindamycin, Ampicillin/Sulbactam,Gentamicin,Oxicillin,Trimeth/Sulfa,Moxifloxacin,Erythromycin,Nitrofurantoin,Levofloxacin,Pennicillin G,and Tetracycline were significantly lower than those of Methicillin-sensitive Staphylococcus epidermidis(MSSE) to the abovementioned antibiotics(P<0.05).The antibiotics with high sensitivity rates for MRSE were Vancomycin(100%),Linezolid(100%), Nitrofurantoin(98.7%),Rifampin(95.8%),Moxifloxacin(72.8%),Levofloxacin(72%),while the antibiotics with high sensitivity rates for MSSE were Vancomycin(100%),Linezolid(100%),Oxicillin(100%),Nitrofurantoin(100%),Rifampin(98.4%), Ampicillin/Sulbactam(98.4%),Moxifloxacin(92.2%),Levofloxacin(92.2%).No Staphylococcus epidermidis with resistance to Vancomycin and Linezolid were found.There were no statistically significant differences of sensitivities to entire antibiotics between Staphylococcus epidermidis in blood/CSF group and non-blood/CSF group,or year 2010 group and year 2011 group.There were no statistically significant differences between Staphylococcus epidermidisisolated blood and non-blood,in the rates of mecA,icaA or icaD genes.Conclusion Staphylococcus epidermidis in pediatric patients are mostly isolated from specimens of blood and mostly distribute in departments of neonatalogy,Gastroenterology and Intense care unit.Most of Staphylococcus epidermidis are MRSE,β-Lactamase positive and multi-drug-resistannt.The change in sensitivity to common antibiotics between different year groups or specimen groups is still steady.Staphylococcus epidermidis show high incidence of mecA gene and low incidence of icaA/icaD genes in this study.