探讨新生儿无乳链球菌医院感染的临床分子流行病学特点及其药物敏感性。

选择2015年1月至2018年12月，于广西壮族自治区妇幼保健院接受治疗时，发生无乳链球菌医院感染的92例新生儿为研究对象，回顾性分析其临床病例资料。采用χ²检验，对病例收集医院的4个新生儿病区中，新生儿无乳链球菌医院感染率进行统计学比较。对分离培养的无乳链球菌，进行标本来源、血清型分型特点及上述2者占比分析。采用纸片扩散法进行无乳链球菌的药物敏感性试验，并分析其耐药性及药物敏感性。本研究符合2013年修订的《世界医学协会赫尔辛基宣言》要求。所有患儿监护人知情同意。

①4个新生儿病区医院感染率：这4个病区包括极早早产儿重症监护病房(ICU)、早产儿ICU、足月儿ICU及新生儿普通病房，其新生儿无乳链球菌医院感染率分别为0.329%(5/1 521)、0.508%(18/3 545)、1.261%(48/3 807))及0.095%(21/22 160)。足月儿ICU的新生儿无乳链球菌医院感染率，分别较其他3个病区高，并且差异均有统计学意义(均为P<0.006)。②标本来源：92份检出无乳链球菌的标本中，占比位列前3位的标本，分别来源于呼吸道分泌物、静脉血及尿液，其占比分别为48.9%(45/92)、22.8%(21/92)及16.3%(15/92)。③早发败血症(EOS)发生率：本组血培养结果无乳链球菌呈阳性的21例患儿中，71.5%(15/21)为EOS。④血清型分型：本组92株无乳链球菌的血清型分型按照其占比高低，位列前3位的血清型依次为Ⅲ、Ⅰb及Ⅴ型，其分别占30.4%(28/92)、27.2%(25/92)及21.7%(20/92)。⑤药物敏感性试验结果：92株无乳链球菌对四环素、克林霉素及红霉素的耐药性均较高，耐药率分别为69.6%(64/92))、57.6%(53/92)、55.4%(51/92)，而对万古霉素、青霉素、利奈唑胺、达福普汀及氨苄西林的敏感性均较高，敏感率均≥87.0%。

尤其对足月儿ICU中住院治疗的新生儿，应警惕无乳链球菌医院感染，以减少该菌所致的EOS等严重感染发生率。本组新生儿病区检出无乳链球菌的血清型以Ⅲ、Ⅰb、Ⅴ型为主，可采用万古霉素、青霉素、利奈唑胺等抗菌药物进行治疗。

To explore clinical molecular epidemiological characteristics and drug sensitivity of nosocomial infection of Streptococcus agalactiae in neonates.

A total of 92 neonates who had nosocomial infection of Streptococcus agalactiae when treated in Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from January 2015 to December 2018, were selected as research subjects. Clinical data of them were retrospectively analyzed. Chi-square test was used to compare the nosocomial infection rate of Streptococcus agalactiae among 4 wards of newborns in case collected hospital. For separated and cultured Streptococcus agalactiae, the sample source and serotyping, also their distribution characteristics were analyzed. The drug sensitivity and resistance of Streptococcus agalactiae were analyzed by paper diffusion method. This study was in line with World Medical Association Declaration of Helsinki revised in 2013. Informed consents were acquired from all guardians.

① Nosocomial infection rates in 4 neonatal wards: the rates of nosocomial infection of Streptococcus agalactiae in intensive care unit (ICU) of extremely premature infants, ICU of preterm infants, ICU of full term infants and neonatal general ward were 0.329% (5/1 521), 0.508% (18/3 545), 1.261% (48/3 807)) and 0.095% (21/22 160), respectively. Among them, the rate of neonatal nosocomial infection of Streptococcus agalactiae in ICU of full term infants were higher than those of other three wards, respectively, and the differences were statistically significant (all P<0.006). ② Specimens source: among 92 specimens which Streptococcus agalactiae were detected, the top 3 ratios of source of specimens from high to low were from respiratory secretion, venous blood and urine, their ratios were 48.9% (45/92), 22.8% (21/92) and 16.3% (15/92), respectively. ③Incidence rate of early onset sepsis (EOS): among 21 neonates whose results of blood culture with Streptococcus agalactiae positive, 71.5% (15/21) were diagnosed as EOS. ④ Serotype: among those strains of Streptococcus agalactiae from 92 specimens, the top 3 distributions of serotype typing from high to low were type Ⅲ, Ⅰb and Ⅴ, their ratios were 30.4% (28/92), 27.2% (25/92) and 21.7% (20/92), respectively. ⑤ Drug sensitivity test results: those 92 strains of Streptococcus agalactiae from 92 specimens were highly resistant to tetracycline, clindamycin and erythromycin, and drug resistance rates were 69.6% (64/92), 57.6% (53/92) and 55.4% (51/92), respectively, but they were highly sensitivity to vancomycin, penicillin, linezolid, dalfopristin and ampicillin, and drug sensitivity rates were all ≥87.0%.

Full term infants in ICU should be particularly vigilant against nosocomial infections of Streptococcus agalactiae to reduce incidence of serious infection complications such as EOS etc.. The serotypes of Streptococcus agalactiae detected in neonatal wards in our hospital were mainly type Ⅲ, Ⅰb, and Ⅴ. Antibacterials such as vancomycin, penicillin, linezolid could be used for treatment of Streptococcus agalactiae infection disease.