Introduction
Postnatal human cytomegalovirus (CMV) infection is usually asymptomatic in term babies, while
preterm infants are more susceptible to symptomatic CMV infection. Breastfeeding plays a
dominant role in the epidemiology of transmission of postnatal CMV infection, but the risk factors
of symptomatic CMV infection in preterm infants are unknown.
Patients and Methods
Between December 2003 and August 2006, eighty Very Low Birth Weight (VLBW) preterm
infants (gestational age ≤ 32 weeks and birth weight < 1500 g), admitted to the Neonatal Intensive
Care Unit of St Orsola-Malpighi General Hospital, Bologna were recruited. All of them were
breastfed for at least one month.
During the first week of life, serological test for CMV was performed on maternal blood.
Furthermore, urinary CMV culture was performed in all the infants in order to exclude a congenital
CMV infection.
Urine samples from each infant were collected and processed for CMV culture once a week. Once
every 15 days a blood sample was taken from each infant to evaluate the complete blood count, the
hepatic function and the C reactive protein. In addition, samples of fresh breast milk were processed
weekly for CMV culture. A genetic analysis of virus variant was performed in the urine of the
infected infants and in their mother’s milk to confirm the origin of infection.
Results
We evaluated 80 VLBW infants and their 68 mothers. Fifty-three mothers (78%) were positive for
CMV IgG antibodies, and 15 (22%) were seronegative.
In the seronegative group, CMV was never isolated in breast milk, and none of the 18 infants
developed viruria; in the seropositive group, CMV was isolated in 21 out of 53 (40%) mother’s
milk.
CMV was detected in the urine samples of 9 out of 26 (35%) preterm infants, who were born from
21 virolactia positive mothers. Six of these infants had clinically asymptomatic CMV infection,
while 3 showed a sepsis-like illness with bradycardia, tachypnea and repeated desaturations. Eight
out of nine infants showed abnormal hematologic values.
The detection of neutropenia was strictly related to CMV infection (8/9 infected infants vs 17/53
non infected infants, P<.005), such as the detection of an increase in conjugated bilirubin (3/9
infected infants vs 2/53 non infected infants, P<.05). The degree of neutropenia was not different
between the two groups (infected/non infected).
The use of hemoderivatives (plasma and/or IgM–enriched immunoglobulin) in order to treat a
suspected/certain infection in newborn with GE< 28 ws was seen as protective against CMV
infection (1/4 infected infants vs 18/20 non infected infants [GE<28 ws]; P<.05).
Furthermore, bronchopulmonary dysplasia (defined both as oxygen-dependency at 30 days of life
and 36 ws of postmenstrual age) correlated with symptomatic infection (3/3 symptomatic vs 0/6
asymptomatic: P<.05).
Conclusion
Our data suggest that CMV infection transmitted to preterm newborn through human milk is always
asymptomatic when newborns are clinically stable. Otherwise, the infection can worsen a preexisting
disease such as bronchopulmonary dysplasia.
Human milk offers many nutritional and psychological advantages to preterm newborns: according
to our data, there’s no reason to contraindicate it neither to pasteurize the milk of all the mothers of
preterm infants who are CMV seropositive.
| Identifer | oai:union.ndltd.org:unibo.it/oai:amsdottorato.cib.unibo.it:969 |
| Date | 09 June 2008 |
| Creators | Capretti, Maria Grazia <1964> |
| Contributors | Faldella, Giacomo |
| Publisher | Alma Mater Studiorum - Università di Bologna |
| Source Sets | Università di Bologna |
| Language | Italian |
| Detected Language | English |
| Type | Doctoral Thesis, PeerReviewed |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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