| BackgroundCytomegalovirus(CMV)can be reactivated in the mammary glands of CMV-seropositive pregnant women,leading to the secretion of CMV into milk.Full-term infants are less likely to develop breast-acquired CMV infection because they have specific antibodies from the mother.However,due to the lack of maternal antibodies acquired through the placenta and immature immune function in premature infants,especially very/extremely preterm infants with birth weight <1500g,breastfeeding has become the main reason for the occurrence of acquired CMV infection,which may lead to multiple organ damage or even death in severe cases.Objective1.To clarify the loads change of CMV in breast milk of very/extremely preterm infants with birth weight < 1500 g after birth.To compare the effectiveness of pasteurization and freeze-thawing methods in reducing the CMV load of breast milk.2.To determine the effect of pasteurized breast milk on the incidence and clinical outcome of acquired CMV infection in very/extremely preterm infants with birth weight < 1500 g.Methods1.Breast milk of very/extremely preterm infants with birth weight < 1500 g who were admitted to the neonatal department of Fujian Provincial Maternity and Child Care Hospital within 24 hours after birth between January 2020 and December 2020 was collected.CMV load of breast milk was detected by fluorescent quantitative polymerase chain reaction(FQ-PCR)every 2 weeks,and the results were plotted.2.The fresh breast milk samples with CMV DNA positive were respectively pasteurized and freeze-thaw treated simultaneously,and the loads of CMV in the breast milk of the three groups were compared and analyzed.3.Very/extremely preterm infants with birth weight < 1500 g and pasteurized breast milk CMV DNA feeding were selected as the pasteurized group in the neonatal department of Fujian Provincial Maternity and Child Care Hospital from January 2020 to December 2020 within 24 hours after birth.Very/extremely preterm infants with birth weight < 1500 g were selected as the artificial feeding group,who were admitted to the neonatal department of Fujian Provincial Maternity and Child Care Hospital within 24 hours after birth from January 2020 to December 2020 and were artificially fed due to their mothers or social factors.Very/extremely preterm infants with birth weight < 1500 g who were fed fresh breast milk during hospitalizations from January 2015 to December 2015 were selected as the fresh breast milk group as the historical control group(CMV DNA testing and pasteurization of breast milk have not been carried out in our hospital).The case data of the three groups were collected and collated to compare the incidence and clinical outcome of acquired CMV infection in very/extremely preterm infants during hospitalization between the three groups.Results1.CMV DNA was detected in breast milk of 88 mothers of very/extremely preterm infants.The positive rate of CMV DNA in breast milk was 84.1%(74/88),and that in colostrum was 20.5%(18/88).The CMV DNA positive rate and colostrum CMV DNA positive rate of very preterm infants were higher than those of extremely preterm infants.There was no statistical significance between the two groups(P > 0.05).2.CMV in breast milk was detected as early as 3 days postpartum.Viral load gradually increased in the first 4 weeks,peaked in the 4th to 6th weeks and gradually decreased.Viral load gradually returned to the initial level about 10 th to12th weeks postpartum.In the peak period of CMV load of milk,the CMV load of breast milk of extremely preterm infants was higher than that of very preterm infants,and the difference was statistically significant(P < 0.05).3.Logarithm(lg)was used for CMV viral load.The average loads(lg)of CMV of fresh breast milk group was 4.06±0.67,the average loads(lg)of CMV of pasteurization group was 3.55±0.78,the average loads(lg)of CMV of freeze-thawing group was 3.69±0.71.One-way analysis of variance showed that the difference in viral load(lg)among fresh breast milk group,pasteurization group and freeze-thawing group was statistically significant(F=13.447,P < 0.05).Then SNK(q test)was used for pair-to-pair comparison.The results showed that:(1)The average CMV load(lg)in the pasteurization group was lower than that in the fresh breast milk group,which was statistically significant;(2)The average CMV load(lg)of breast milk in freeze-thawing group was lower than that in the fresh breast milk group,which was statistically significant;(3)The average CMV load(lg)in the pasteurization group was lower than that in the freeze-thawing group,but the difference was not statistically significant.CMV DNA clearance rate in pasteurization group was higher than that in freeze-thawing group,and the difference was statistically significant(P < 0.05).4.The acquired CMV infection rate(3.9%)in the pasteurized group was significantly lower than that in the fresh breast milk group(19.2%).The acquired CMV infection rate of very/extremely preterm infants in the pasteurization group were similar to those in the artificial feeding group(3.3%),and the difference was not statistically significant.5.The incidence of symptomatic infection among the three groups of CMV infection was 100% in the artificial feeding group,66.7% in the pasteurized group,and 80% in the fresh breast milk group.There was no significant difference in the clinical symptoms of acquired CMV infection among the three groups(P < 0.05).There was no death or severe infection cases in the three groups.6.The average weight gain rate(g/d)in fresh breast milk group was significantly higher than that in the artificial feeding group and the pasteurization group(P < 0.05),and the average weight gain rate(g/d)in the pasteurization group was higher than that in the artificial feeding group,However,there was no statistical significance between the two groups(P > 0.05).Conclusions1.The positive rate of CMV in breast milk of very/extremely preterm infants is high,and CMV has been excreted in part of colostrum.CMV load reaches its peak at about 4-6 weeks and gradually returns to the initial level at about 10-12 weeks.During the peak period,the CMV load in the milk of the mothers of extremely preterm infants was significantly higher than that of the mothers of very preterm infants.2.Pasteurization and freeze-thawing treatment can effectively reduce the CMV DNA load of breast milk.The CMV clearance rate of pasteurization is significantly higher than that of freeze-thawing breast milk.3.Compared with fresh breastfeeding,the very/extremely preterm infants fed with pasteurized CMV DNA-positive breast milk have a significantly lower incidence of acquired CMV infection and reduced clinical symptoms and comorbidities.The incidence of acquired CMV infection in very/extremely preterm infants with pasteurized breast milk is similar to artificial feeding. |
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