新生儿痰真菌生长的临床意义及相关因素探讨

目的探讨新生儿痰真菌生长的临床意义及相关因素。方法回顾性分析149例诊断为新生儿肺炎且痰培养结果阳性住院新生儿的临床资料,根据痰培养结果将患儿分为真菌组、混合组和细菌组,运用Х^2检验及方差分析等统计学方法,比较三组的临床资料。结果（1）真菌组40例、混合组30例和细菌组79例,痰真菌生长占47．0％（70／149）。（2）三组间白细胞数分别为（10．3±3．5）×10^9／L、（11．7±5．2）×10^9／L和（14．4±10．5）×10^9／L,F=3．78,P=0．03;中性粒细胞数分别为（5．1±3．3）×10^9／L、（7．4±4．7）×10^9／L、（9．0±7．4）×10^9／L,F=5．50,P=0．01;下列因素所占比例,三组分别为：早产儿32．5％（13／40）、20％（6／30）和12．7％（10／79）,Х^2=6．68,P=0．04;母产前使用糖皮质激素10．0％（4／40）、6．7％（2／30）和0％（0／79）,P=0．01;使用三联抗生素治疗10．0％（4／40）、16．7％（5／30）和2．5％（2／79）,P=0．02;碳青霉烯类药物治疗32．5％（13／40）、63．3％（19／30）和17．7％（14／79）,Х^2=21．26,P=0．00。上述6个因素三组间差异均有显著统计学意义。（3）以痰真菌生长作为因变量进行Logistic回归分析,共2个变量进入最佳回归方程：碳青霉烯类药物（克倍宁或泰能）治疗（X1）、早产儿（X2）,建立影响痰真菌生长的主效应模型Logistic（SCF）=β0（0．12）＋1．63X1＋1．20X2（Х^2=43．04,P〈0．05）。（4）仅一次痰真菌生长,抗真菌治疗与否未愈率分别为10．0％（2／22）和0％（0／43）,P=0．111;继续住院时间分别为（225．8±7．7）d和（434．1±4．7）d,t=1．095,P=0．278,均无统计学意义。结论（1）在新生儿肺炎中,痰真菌生长比较普遍,以白色念珠菌为主。（2）早产儿、碳青霉烯类抗生素治疗可作为痰真菌生长的独立危险因素。（3）仅一次痰真菌生长只提示需作进一步真菌检查,不能凭此确诊肺部真菌感染或决定是否抗真菌治疗。

Clinical value and multiple risk factors analysis of sputum culture for fungus in neonates

OBJECTIVE: In recent years, the incidence of fungal infection in neonates has been risen year by year, but there are no widely accepted criteria to identify the clinical significance of the culture results of secretion from lower respiratory tract at present. The aim of the present study was to understand the clinical value and risk factors of fungal infections as suggested by sputum culture in neonates, which may help clinicians to diagnose and treat the neonates with fungal infection of respiratory tract. METHODS: One hundred and forty nine neonates with positive sputum culture results and suffered from pneumonia hospitalized from October, 2002 to May, 2005 in Children's Hospital of Chongqing Medical University were analyzed. The cases were divided into three groups according to the results of sputum culture. Forty cases who were only fungus positive were enrolled into the fungal group, 30 cases who were positive for both fungus and bacteria were classified into the mixed group, and the remaining 79 cases who were positive for bacteria only were recruited into bacterial group. Several clinical characteristics of neonates from the three groups were compared retrospectively. t test, chi-square test and Logistic regression analysis were used for statistical analyses. RESULTS: Seventy of the 149 patients (47.0%) had fungal infections. Candida was the main genus cultured from sputum. Rate of resistance to fluconazole was 25.7% (9/35). Candida albicans was the most common strain, which was found in 56.9% of cases whose sputum culture was positive for fungi. In fungal group (n = 40), mixed group (n = 30) and bacterial group (n = 79), white blood cell count were (10.3 +/- 3.5) x 10(9)/L (11.7 +/- 5.2) x 10(9)/L and (14.4 +/- 10.5) x 10(9)/L, respectively, F = 3.78, P = 0.03, with neutrophil count (5.1 +/- 3.3) x 10(9)/L, (7.4 +/- 4.7) x 10(9)/L and (9.0 +/- 7.4) x 10(9)/L, respectively, F = 5.50, P = 0.01. Ratios of risk factors were as follows:for preterm infant, 32.5% (13/40), 20% (6/30) and 12.7% (10/79), chi(2) = 6.68, P = 0.04; for antepartum glucocorticoid used, 10.0% (4/40), 6.7% (2/30) and 0% (0/79), P = 0.01; for trilogy of antibiotics used, 10.0% (4/40), 16.7% (5/30) and 2.5% (2/79), P = 0.02; for therapy with carbapenems (Carbenin or Tienam), 32.5% (13/40), 63.3% (19/30) and 17.7% (14/79), chi(2) = 21.26, P = 0.00. There was significant difference among the three groups in the above factors respectively. Using the sputum culture results with or without fungus as the dependent variable, multivariate logistic regression showed that preterm infant (X(1)) and the therapy with carbapenems (X(2)) suited the best regression equation: Logistic (SCF) = beta(0) (0.12) + 1.63X(1) + 1.20X(2) (chi(2) = 43.04, P < 0.05). CONCLUSION: Fungal growth in sputum culture in the neonates with pneumonia was common, Candida was the main genus, and Candida albicans was the most common one. Prematurity and the therapy with carbapenems were the most important independent risk factors associated with fungal growth in culture of sputum specimen from neonates.