Study On The Correlation Between The Fungal Colonization And Fungal Sepsis In Neonatal Intensive Care Unit

Objectives(1) To investigate the incidence,location, length of stay and main strain of fungal colonization in the neonates and analyse the risk factors of fungal colonization in neonatal intensive unit(NICU).(2) To analyse the clinical features, pathogens distribution of premature infants with fungal sepsis and the risk factors of suffering from fungal sepsis in NICU.(3) To study the genotype of colonized and pathogenic fungal strains a nd investigate the correlation between the fungal colonization and fungal sepsis in NICU.Methods(1) Swabs from the oropharynx, navel, groin, perineum and a nus of 229 newborns in NICU were collected,and fungal strains cultured and isolated respectively. Fungal species were identified by Vitek mass spectrometer and sequenc ing with ITS1-typing. 28 patients with colonized fungal strains as observed group and 30 patients without colonized fungal strains as control group were analysed by case control study.(2) 55 preterm infants with fungal sepsis from three hospital in Shenzhen as observed group and 55 preterm infants without sepsis, who were similar to gestational age and admission time as control group were analysed by case control study.(3) Fungal strains of preterm infants with sepsis from 2003 to 2013 in the NICU of Shenzhen People’s Hospital were revived. The genotypes of pathogenic and colonized fungal strains were analysed by multilocus sequence typing(MLST) and multiple- locus variable number tandem repeat analysis(MLVA). The homologous of genotypes were analysed by the cluster analysis and phylogenetic analysis.Results(1) The incidence of fungal colonization was 12.23% in NICU of Shenzhen People’s Hospital,the constituent ratio of Candida was 82.54%, and the Candida albicans accounted for 67.31% of Candida. The main fungal colonized parts of body were the groin, perineum and anus. The logistic regression analysis showed that vaginal delivery(OR:18.294 CI:3.365,99.444 p<0.05)and infection during pregnancy(OR:11.323 CI:2.080, 61.638 p < 0.05) were independent risk factors of neonates with fungal colonization in NICU.(2) The mortality was 3.64% of 55 preterm infants with fungal sepsis in three hospitals of Shenzhen city.The symptoms and signs were no specific in preterm infants with fungal sepsis. The logistic regression analysis showed that the PICC(OR:9.116 CI:0.710,117.062 p<0.05), the number of neutrophils less than 1.5x109 /Lafter a week of birth(OR:17.333 CI:1.774,169.367 p<0.05) and the using time of antibiotics(OR:0.913 CI:0.848,0.984 p<0.05) were independent risk factors of preterm infants with fungal sepsis.(3) 10 ST genotypes, including 3 new ST genotypes were founded in 36 colonized Candida albicans strains, 5 ST genotypes which were ST1867, ST2551, ST2552, ST2937, and ST2945 respectively were detected in 12 Candida albicans strains from the preterm infants with fungal. According to the phylogenetic tree, epidemic strains of colonized Candida albicans were Goup1 and Goup2, and strains of pathogenic Candida albicans was N3 clone group. The same genotypes of Candida albicans were not founded between colonized and pathogenic strains. 5 colonized candida parapsilosis strains were independent genotypes. 8 genotypes were detecte in 11 candida parapsilosis strains isolated from 8 preterm infants with fungal sepsis, in which two patients with the same genotype.Conclusions:(1) Candida albicans are the main colonized fungal strains. Vaginal delivery and the mother infection during pregnancy are independent risk factors of preterm infants with fungal colonization in NICU.(2) The symptom and sign are non specific of the preterm infants with fungal sepsis. The PICC, the number of neutrophils less than 1.5x109 after a week of birth, and the length of using antibiotics are independent risk factors of preterm infants with fungal sepsis.(3) 10 genotypes are isolated from 37 Candida albicans strains. The genotypes of the Candida albicans from preterm infants fungal sepsis are ST1867, ST2551, ST2552, ST2937, and ST2945. 8 genotypes are isolated from 11 candida parapsilosis strains in the preterm infants with fungal sepsis.Two patients isolated the same genotype, and the other funguses are independent types. There are not the same genotype in colonized and pathogenic Candida albicans and parapsilosis strains.