新生儿重症监护室金黄色葡萄球菌定植菌株的耐药性及生物膜形成能力研究

Antibiotic resistance and biofilm formation of Staphylococcus aureus colonization among neonatal intensive care units

目的 研究北京儿童医院新生儿重症监护病房(NICU)患儿鼻前庭金黄色葡萄球菌(简称金葡菌)的定植情况及定植菌株的药物敏感性、生物膜形成能力。方法 前瞻性收集2015年5月至2016年3月于北京儿童医院NICU住院患儿鼻前庭分离出的金葡菌,前期已进行分子分型,本次实验利用E-test法检测金葡菌对临床常用抗菌药物的药物敏感性,结晶紫染色实验检测定植菌株的生物膜形成能力。结果 536例鼻拭子分离出96株金葡菌,定植率为17.9%。其中,耐甲氧西林金葡菌(MRSA) 28株,甲氧西林敏感金葡菌(MSSA)有68株。MRSA菌株对青霉素、苯唑西林、头孢曲松、红霉素和夫西地酸耐药率分别为100%、57.1%、78.6%、92.9%和3.6%。MSSA菌株对青霉素、头孢曲松、红霉素、庆大霉素的耐药率分别为82.4%、8.8%、47.1%和16.2%。MRSA中有14.3%苯唑西林敏感甲氧西林耐药金葡菌(OS-MRSA)。定植菌株的生物膜阳性率91.7%,MRSA和MSSA在生物膜形成能力方面没有显著差异,不同ST型菌株生物膜形成能力存在差异(P=0.0276),产膜菌株与非产膜菌株的药物敏感性无明显差异。结论 定植的金葡菌常对青霉素、红霉素耐药,对其他临床常用抗菌药物敏感性较好,有一定比例OS-MRSA。定植菌株生物膜阳性率高,不同分型菌株生物膜形成能力不同。

Objective To investigate the antibiotic resistance and biofilm formation of Staphylococus aureus(S.aureus) isolates colonization among neonates in neonatal intensive care unit(NICU) of Beijing Children’s Hospital.Methods Surveillance of nasal swabs from neonates were conducted in NICU of Beijing Children’s Hospital from May of 2015 to March of 2016. The antibiotic resistance was determined by the E-test method. Biofilm-forming ability was assessed using the crystal violet staining method. Results There were 96 children of 536 cases(17.9%)were isolated S. aureus in their nose, including 28 MRSA strains and 68 MSSA strains. For MRSA strains, the rates of antibiotic resistance to penicillin, oxacillin, ceftriaxone, erythromycin, and fusidic acid were 100%, 57.1%, 78.6%,92.9%, and 16.2%, respectively. The rates of antibiotic resistance of MSSA to penicillin, ceftriaxone, erythromycin,and gentamicin were 82.4%, 8.8%, 47.1%, and 16.2% respectively. Oxacillin-susceptible mecA-positive S. aureus(OS-MRSA) was found, accounting for 14.3% of MRSA. Biofilm formation was observed in 91.7% isolates of S. aureus. There was no significant difference in the efficiency of biofilms-forming between MRSA and MSSA.The difference of biofilm-forming ability was found between STs(P=0.0276). However, there was no difference of antibiotic resistance identified between isolates with or without biofilm formation ability. Conclusion Colonization strains were often resistant to penicillin and erythromycin, while usually sensitive to other tested antibiotics. There was a certain percentage of OS-MRSA. The rate of biofilm producing S. aureus was high among colonization strains.Biofilm-forming ability varied among different types.