Certain type of chronic lung disease of newborns is associated with Ureaplasma urealyticum infection in utero

BACKGROUND: Recent studies of chronic lung disease (CLD) of newborns emphasize the contribution of antenatal infection. However, the association of Ureaplasma urealyticum infection and CLD has been controversial. The purpose of the present paper was to determine whether U. urealyticum is associated with chorioamnionitis (CAM) and a certain type of CLD. METHODS: One hundred and five infants <32 weeks of gestation who were admitted to the neonatal intensive care unit at Jichi Medical School Hospital, who underwent both histological and microbiological examinations and who survived to discharge were included. CAM was determined by histological examination. Placenta, gastric and tracheal aspirates, and nasopharyngeal swabs were cultured for Mycoplasma and other microorganisms. CLD was defined as oxygen needed at 28 days of age with symptoms of persistent respiratory distress and hazy or emphysematous and fibrous appearance upon X-ray. CLD was further divided into two subtypes according to the presence of antenatal infection. RESULTS: CAM was associated with premature rupture of membrane (odds ratio [OR], 10.19; 95% confidence interval [CI]: 3.10-33.56), placental colonization of U. urealyticum (OR 6.73, 95%CI: 1.89-23.91), neonatal colonization of other microorganisms (OR 7.33, 95%CI: 1.22-44.13) and level of IgM (OR 1.06, 95%CI: 1.01-1.11). Comparisons between CLD and non-CLD patients showed that gestational age (OR 0.43, 95%CI: 0.30-0.61) and white blood cell count (WBC) at birth (OR 1.06, 95%CI: 1.01-1.11) were risk factors for CLD, while gestational age (OR 0.38, 95%CI: 0.23-0.64), neonatal colonization of U. urealyticum (OR 5.98, 95%CI: 1.17-30.6) and WBC (OR 1.08, 95%CI: 1.01-1.15) were independent risk factors for infection-related CLD compared with non-CLD. Within CLD, infection-related CLD was associated with neonatal colonization of U. urealyticum (OR 43.7, 95%CI: 2.84-673.8) and WBC (OR 1.27, 95%CI: 1.07-1.50). CONCLUSIONS: Placental colonization of U. urealyticum was significantly related to CAM; and neonatal colonization of U. urealyticum and leukocytosis at birth were risk factors for infection-related CLD.     

Ureaplasma urealyticum and its association with chronic lung disease in Asian neonates

OBJECTIVE: The aim of the present prospective cohort study was to evaluate the relationship between lower respiratory tract colonization with Ureaplasma urealyticum and development of chronic lung disease (CLD) in a high-risk neonatal population. METHODS: Prospective cohort study of preterm infants with a birthweight < 1,500 g needing mechanical ventilation within 24 h of birth in a tertiary care neonatal unit. Endotracheal aspirates from these infants were cultured within 24 h for U. urealyticum and the rate of colonization was determined. The primary outcome measure was the incidence of CLD at 28 days of life. RESULTS: Of the 41 infants studied, 10 (24%) infants were colonized with U. urealyticum. The colonization rate was higher in babies < 1,000 g compared with babies weighing 1,000-1,500 g (P = 0.04). There was no significant difference between the colonized and non-colonized groups with regard to the antenatal use of steroids, maternal prolonged rupture of membranes, gestational age, birthweight, sex, respiratory distress syndrome, use of surfactant, patent ductus arteriosus and gastrooesophageal reflux. Of the 37 survivors, 20 (54%) developed CLD; eight infants (88.5%) in the colonized group developed CLD compared with 12 infants (42.8%) in the non-colonized group (P = 0.01). CONCLUSIONS: Neonates colonized with U. urealyticum were twice as likely to have CLD than non-colonized babies (relative risk 2.01; 95% confidence interval 1.27-3.37). These data suggest a significant association between colonization with U. urealyticum and CLD in infants weighing < 1,500 g.     

Role of Ureaplasma urealyticum and other pathogens in the development of chronic lung disease of prematurity

A prospective cohort study enrolling 107 infants weighing less than 1250 g was conducted between September 1, 1986, and November 15, 1987 in order to determine the role of microorganisms on the development of chronic lung disease (CLD). Ureaplasma urealyticum was isolated significantly more frequently from gastric aspirates and nasopharyngeal or endotracheal aspirates from 43 infants developing CLD than from 56 who did not (51% vs. 16%; P less than 0.005). Infants developing CLD, defined by radiographic and blood gas abnormalities, were significantly younger (26 vs. 29 weeks; P less than 0.0001), weighed significantly less (830 vs. 1050 g; P less than 0.0001) and required more ventilatory support (37 vs. 10 were being ventilated and 42 vs. 26 received oxygen supplementation on Day 7) compared with those who did not develop CLD. Viruses were isolated in association with U. urealyticum in two infants developing CLD and in one infant who did not develop CLD. Mycoplasma hominis was isolated from three infants who were colonized with U. urealyticum and developed CLD. Chlamydia trachomatis was not recovered from any patients. From a discriminant analysis it was found that U. urealyticum contributed to the development of CLD along with the effect of ventilatory support, gestational age and severity of initial respiratory disease. The effect of interventions directed against U. urealyticum on the development of CLD deserves further study.     

Respiratory distress syndrome in infants with impaired intrauterine growth

The recently introduced intrauterine growth curve, based on ultrasonically estimated foetal weights, was retrospectively applied to an inborn population of 883 infants bom before 33 gestational weeks at the University Hospital of Lund, during 1985–94. The estimation of birthweight deviation resulted in 630 (71.3%) infants with a birthweight appropriate for gestational age (AGA), 244 (27.6%) infants with a birthweight small for gestational age (SGA) and 9(1.1%) infants with a birthweight large for gestational age. Birthweight deviation was associated with an increased mortality [odds ratio (OR) adjusted for gestational age 1.29 per SD (12%) change in birthweight for gestational age, 95% CI: 1.10–1.50; p = 0.002]. At gestational age 25–28 weeks, SGA-infants had an increased incidence of respiratory distress syndrome (RDS) as compared to AGA-infants (OR adjusted for gestational age: 1.98,95% CI: 1.12–3.52; p = 0.019). At gestational age 29–32 weeks, SGA-infants had a lower incidence of RDS as compared to AGA-infants (OR adjusted for gestational age: OR 0.52,95% CI: 0.34–0.80; p = 0.003). After adjustment for confounding variables, infants born at gestational age 25–28 weeks from mothers with pre-eclampsia, appeared to be a high-risk group for RDS, whereas at the age of 29–32 gestational weeks, negative birthweight deviation had a protective effect against RDS. Antenatal corticosteroid administration appeared to have a less beneficial effect on mortality, RDS and cerebral haemorrhage in infants born SGA vs in those born AGA.     

Infection with Ureaplasma urealyticum: is there a specific clinical and radiological course in the preterm infant?

BACKGROUND: Despite having mild early respiratory disease, many preterm babies develop chronic lung disease (CLD). Intrauterine infection with Ureaplasma urealyticum has been associated with preterm labour and CLD. OBJECTIVE: To test the hypothesis that infection with U urealyticum results in a specific clinical and radiological picture in the first 10 days of life. METHODS: Retrospective study of 60 ventilated babies < 30 weeks gestation, who had tracheal secretions tested for U urealyticum. Placental histology was reviewed by a paediatric pathologist for signs of chorioamnionitis. Chest radiographs were independently reviewed by two paediatric radiologists according to previously agreed criteria. All reviewers were blinded to the infection status of the babies. RESULTS: Twenty five babies were U urealyticum positive. These were more likely to experience chorioamnionitis (p = 0.004), premature rupture of membranes (p = 0.01), and spontaneous vaginal delivery (p = 0.09). U urealyticum positive babies had fewer signs of respiratory distress syndrome on early chest radiographs (p = 0.038), and they could be weaned from their ventilation settings (fraction of inspired oxygen (FIO(2)) and mean airway pressure) more quickly in the first few days. Subsequently U urealyticum positive babies deteriorated clinically and radiologically. More often they required ventilation to be restarted (p = 0.051), a higher proportion being ventilated on day 10 (p = 0.027) with higher FIO(2) (p = 0.001) and mean airway pressure (p = 0.002). Their chest radiographs showed more emphysematous changes as early as day 5 (p = 0.045), with a pronounced difference by day 10 (p = 0.009). CONCLUSIONS: Preterm ventilated babies with U urealyticum in their tracheal secretions have a different clinical and radiological course, with less acute lung disease but early onset of CLD, compared with those with negative cultures.     

Polymerase chain reaction-amplification of urease genes: rapid screening for ureaplasma urealyticum infection in endotracheal aspirates of ventilated newborns

Ureaplasma urealyticum infection has been considered to play an important role in the development of bronchopulmonary dysplasia (BPD) in premature infants. Since standard culture methods of U. urealyticum are difficult to perform, new rapid and sensitive methods are needed to detect lung infection of ventilated newborns. Here we describe the polymerase chain reaction as a rapid method to screen endotracheal aspirates for ureaplasma infection. Urease-specific sequences could only be detected in 1 out of 36 ventilated newborns. The procedure described in this paper may facilitate further studies to determine the role of U. urealyticum in development of BPD.     

Cytological changes in endotracheal aspirates associated with chronic lung disease

Endotracheal aspirates taken serially from mechanically ventilated premature infants born at <28 weeks gestation between March 1992 and August 1993 were studied to determine whether early cytological changes would be a good predictor of lung damage in infants who develop chronic lung disease (CLD). CLD was diagnosed if the infant required supplemental oxygen at 36 weeks corrected gestational age. Fifty-five infants were enrolled in the study, five died and of the 50 infants remaining, 17 (34%) developed CLD. The infants with CLD had a significantly lower gestation (25.5±1.8 (mean±1 SD) versus 26.2±0.9 weeks, p<0.05), significantly more required surfactant (14/17 vs. 16/33, p<0.05) and were ventilated for a significantly longer period (43.3±26.6 vs. 19.3±12.8 days, p<0.0001). Endotracheal aspirate cytology showed that infants with CLD had significantly more degenerated columnar epithelial cells on day 3 (p=0.001), and more neutrophils on day 10 (p=0.007). Though not predictive of CLD, cytological changes consistent with bronchial epithelial and pulmonary damage followed by an inflammatory response were found in the tracheal aspirates of a group of infants clinically diagnosed with CLD.     

Development of chronic lung disease in preterm infants treated with surfactant

BACKGROUND: Chronic lung disease (CLD) is generally known to develop among preterm infants who have severe respiratory distress syndrome (RDS) at birth. Many clinical trials have established the efficacy of surfactant replacement therapy to treat RDS at birth with differing doses. In this study, the preterm infants diagnosed to have RDS at birth and treated with one or two doses of surfactant, depending on the severity of the RDS, were studied to evaluate the effect of surfactant on the later development of CLD. METHODS: A retrospective examination of case records of preterm infants who were born at < or = 28 weeks gestation period were studied. The subjects received a natural surfactant product (survanta) between September 1994 and April 1996 at the Monash Medical Center, Australia. RESULTS: Despite less severe initial lung disease, the subsequent respiratory outcome of infants who received one dose of surfactant, showed a trend towards being poorer compared to those who were diagnosed as having severe RDS at birth and received two doses of surfactant. At the corrected gestational age of 36 weeks, 54% of those infants began with mild RDS required oxygen, while only 44% of those who started with a severe RDS required supplemental O2. CONCLUSION: This study reports the infants with severe RDS at birth had responded slightly better or equally, compared to those with mild RDS, in terms of later development of CLD under surfactant treatment proportional to the severity.     

Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study

OBJECTIVE: To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins. METHODS: A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI). RESULTS: Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries. CONCLUSIONS: VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery.     

Early increased levels of matrix metalloproteinase-9 in neonates recovering from respiratory distress syndrome

AIM: Matrix metalloproteinases (MMPs) play an eminent role in airway injury and remodelling. We explored the hypothesis that pulmonary MMP levels would differ early after birth (2-4 days) between infants with resolving respiratory distress syndrome (RDS) and infants developing chronic lung disease of prematurity (CLD). METHODS: Thirty-two prematurely born infants (gestational age < or =30 weeks) diagnosed with RDS were included. In 13 infants RDS resolved while 19 developed CLD. MMP-2 and MMP-9 in bronchoalveolar lavage (BAL) fluids collected on postnatal days 2, 4, 7 and 10 were analyzed by zymography and densitometry. Immunochemistry was performed on BAL cells and lung tissue to identify cellular sources of MMP-9 in RDS and CLD. RESULTS: Median MMP-9 levels increased significantly on day 2 in BAL fluid from patients with resolving RDS (median values MMP-9 = 42.0 arbitrary units (AU)) compared to CLD patients (MMP-9 = 5.4 AU). MMP-9 and neutrophil lipocalin-associated MMP-9 (NGAL) were significantly higher on day 4 in BAL fluid from resolving RDS (MMP-9 = 65.8 AU; NGAL = 16.1 AU) compared to CLD (MMP-9 = 25.4 AU; NGAL = 2.0 AU), Levels of MMP-9 and NGAL increased subsequently on days 7 and 10 in CLD. No differences in MMP-2 levels were detected between RDS and CLD. Neutrophils, macrophages and alveolar type-II epithelial cells were identified as potential sources of MMP-9. CONCLUSION: Our findings indicate differences in early MMP-9 BAL fluid levels between resolving RDS and developing CLD, which may relate to the ability to raise an early and adequate response to the initial injury.     

Clinical characteristics of chronic lung disease without preceding respiratory distress syndrome in preterm infants

BACKGROUND: Recently, the incidence of atypical presentation of chronic lung disease (CLD) that develops in infants without a history of preceding respiratory distress syndrome (RDS) is increasing. Therefore, the clinical characteristics of CLD without RDS in comparison with CLD with RDS were assessed. METHODS: Prospective cohort analysis was done from 117 very low-birthweight infants who were born in Seoul National University Hospital and survived more than 36 weeks postmenstrual age (PMA). RESULTS: Of the 117 infants analyzed, CLD developed in 44 infants (38%). Among these 44 infants, CLD with RDS developed in 27 infants (23%) and CLD without RDS developed in 17 infants (15%). Each type of CLD was subgrouped according to the presence of chorioamnionitis (CA): RDS(+)CA(+) CLD (n = 8) and RDS(+)CA(-) CLD (n = 19); and RDS(-)CA(+) CLD (n = 12) and RDS(-)CA(-) CLD (n = 5). There were no significant differences in the demographic characteristics between CLD with RDS and CLD without RDS. Chorioamnionitis was significantly more common in CLD without RDS, while patent ductus arteriosus was more common in CLD with RDS. Although the severity of initial respiratory failure was not greater than that of CLD with RDS, CLD without RDS showed a gradually increasing chronic oxygen requirement pattern. Chronic oxygen requirement pattern showed that infants with RDS(+)CA(+)CLD required the highest concentrations of oxygen not only initially but also thereafter until the 28th day of life and 36 weeks PMA. CONCLUSIONS: Although CLD without RDS was still less common than CLD with RDS, it comprised over a third of all cases of CLD in our study. Clinical characteristics and chronic oxygen requirement pattern of CLD without RDS seems to be less severe than those of CLD with RDS. Our data suggest that CLD without RDS may be developed by causes other than initial acute lung injury. Chorioamnionitis may be one of antecedents of CLD without RDS.     

Identification and quantification of ureaplasmas colonizing the respiratory tract and assessment of their role in the development of chronic lung disease in preterm infants.

BACKGROUND: The role of Ureaplasma urealyticum in the development of chronic lung disease (CLD) in preterm infants continues to be disputed. Recently U. urealyticum has been found to consist of two species, U. urealyticum and Ureaplasma parvum, a finding that has not been considered in previous studies of CLD. This study examined the possible relationships between development of CLD and respiratory colonization by these newly redefined species, their concentrations in lower respiratory secretions and the effect of pulmonary surfactant treatment on these relationships in preterm infants with birth weights < 1500 g. METHODS: Endotracheal aspirates (ETA) were collected from intubated infants when airway suctioning was medically required. ETA were stored at -80 degrees C until quantitative cultures for ureaplasmas and Mycoplasma hominis were performed. Culture results were correlated with development of CLD. RESULTS: Of 475 infants (birth weights < 1500 g) admitted during the 2-year study period, 272 were excluded because they were not intubated or were extubated before ETA could be obtained. An additional 28 infants died, were discharged or were transferred before they could be assessed for CLD. From the remaining 175 infants ureaplasmas were isolated from 66 (38%). No statistically significant associations were identified between development of CLD and the Ureaplasma species isolated, or concentration of ureaplasmas in lower respiratory secretions. These findings were not altered by treatment with pulmonary surfactant (Survanta). CONCLUSION: Lower respiratory colonization by ureaplasmas does not appear to be a contributory cause of CLD in preterm infants.     

Fibroblast mitogenic activity of lung lavage fluid from infants with chronic lung disease of prematurity

BACKGROUND: Lung fibrosis is thought to be important in chronic lung disease of prematurity (CLD). METHODS: Fibroblast proliferative activity was assessed in 207 bronchoalveolar lavage fluid (BALF) samples from 43 infants. Sixteen developed CLD (birth weight 765 g (630-1230), gestation 26.5 weeks (23-29)), 18 developed respiratory distress syndrome (RDS) (birth weight 1415 g (430-4160), gestation 31 weeks (23-39)), and nine control infants (birth weight 2110 g (900-3720), gestation 32 weeks (26-41)) received mechanical ventilation for non-pulmonary reasons. RESULTS: The fibroblast proliferative activity relative to 10% fetal calf serum was 64-75% in infants with CLD, 55-86% in the RDS group, and 42-68% in control infants during the first 5 weeks of life. Only at day 3 was there a difference between the groups (CLD 72% v control 42%, p < 0.01; RDS 63% v control 42%, p < 0.05). With the use of neutralising antibodies, platelet derived growth factor BB (PDGF-BB) and epidermal growth factor were undetectable, and insulin-like growth factor I (IGF-I) accounted for 14% (p < 0.05) and 11% (p < 0.005) of BALF mitogenic activity from the RDS and CLD groups respectively. CONCLUSIONS: The mitogenic activity of BALF was similar in the three groups studied and was only partially accounted for by IGF-I. Growth factors other than PDGF-BB and IGF-I contribute significantly to this process.     

Colonization by Ureaplasma urealyticum and chronic lung disease in premature newborn infants under 32 weeks of gestation]

Colonization of the respiratory tract of premature newborn infants by genital mycoplasma is suspected to be associated with chronic lung disease. METHODS AND PATIENTS: We prospectively determined the prevalence of genital mycoplasma colonization with nasopharyngeal or endotracheal culture in preterm neonates younger than 32 weeks gestation and its possible association with the development of chronic lung disease in a prospective study. RESULTS: Fifty-nine infants were enrolled and 11 (19%) were colonized with Ureaplasma urealyticum. In the subgroup of 45 ventilated infants, seven of seven U. urealyticum-positive infants developed chronic pulmonary disease versus ten of 38 (26%) of U. urealyticum-negative infants (relative risk [RR] = 3.8; 95% confidence interval [CI] 2.2 to 6.5, P < 0.001). U. urealyticum-colonized infants had a lower median birth weight (760 vs 1,083 g, P = 0.04), a lower gestational age (26 vs 28 weeks, P = 0.03), and a higher incidence of symptomatic patent ductus arteriosus (P = 0.03). These potential confounding factors may partially explain the association between U. urealyticum and chronic pulmonary disease. However, this association remained statistically significant when the analysis was restricted to infants with birth weight of 1,000 g or less (RR = 2.3; 95% CI 1.3 to 4, P = 0.02) or to infants with a patent ductus arteriosus (RR = 2; 95% CI 1.3 to 3.1, P = 0.02). CONCLUSION: Colonization with U. urealyticum in ventilated preterm neonates younger than 32 weeks gestation is a significant risk factor of developing chronic pulmonary disease.     

Tracheobronchial aspirate fluid neutrophil lipocalin,elastase- and neutrophil protease-4-alpha1-antitrypsin complexes,protease inhibitors and free proteolytic activity in respiratory distress syndrome

This study aimed to determine whether the protease/protease inhibitor balance and neutrophil activity is of pathophysiological importance in the severity and resolution of respiratory distress syndrome (RDS) and the eventual development of neonatal chronic lung disease (CLD). Ventilated preterm infants with RDS (n = 43) were studied during their first week of life. Tracheobronchial aspirate fluid (TAF) concentrations of neutrophil lipocalin, the elastase- and neutrophil protease-4 (NP4) complex concentrations, and alpha1-antitrypsin (alpha1AT), antichymotrypsin (ACT) and secretory leucocyte protease inhibitor (SLPI) levels were analysed. Free proteolytic and elastolytic activities were also determined. CLD correlated with low alpha1AT (p = 0.02) and ACT (p = 0.02) levels at 3-4 d of age and low SLPI (p = 0.03) at 7-8 d of age. No correlations were found between CLD or severity of RDS (as judged from radiological examination) and neutrophil lipocalin, elastase- and NP4-alpha1AT complexes during the first week of life, with one exception: RDS X-ray severity and the elastase-alpha1AT complex concentration were correlated at 3-4d of age (p = 0.02). Free proteolytic activity occurred in the TAF of 7/30 infants tested on day 3-4 and free elastolytic activity in 1 patient. During the rest of the first week of life no free elastolytic or proteolytic activities were observed. Caesarean section was correlated with low levels of SLPI on day 3-4 (p = 0.01), NP4 (p = 0.03) and ACT (p = 0.05) on day 5-6. Gestational age was positively correlated with protease inhibitors and their complexes at 3-4 d of age. Conclusion: Free proteolytic or elastolytic activity in the TAF of RDS infants in the first week of life occurred by way of exception. Elastase-/NP4-alpha1AT complex or neutrophil lipocalin levels were not correlated with the development of CLD. The correlation between CLD and low alpha1AT or ACT at 3-4 d and SLPI at 7-8 d of age may be due to either immaturity or complex formation. The severity of RDS as judged from radiological examination was correlated with elastase-alpha1AT complex on day 3-4. The main hypothesis, that TAF protease/protease inhibitor levels or imbalance and leucocyte activity are important factors indicating a high risk of severe RDS and subsequent CLD development, was principally not confirmed.     

Ontogeny of unconjugated estriol in fetal blood and the relation of estriol levels at birth to the development of respiratory distress syndrome

Unconjugated estriol (E3) was quantified in serum of umbilical cord blood of 533 newborn infants, 360 of whom were delivered between 23 and 37 wk of gestation. Serum E3 levels rose (F = 7.71, p less than 0.0001) as a function of gestational age; the mean concentration of E3 at 37.5-42 wk of gestation (105 ng/ml, n = 173) was significantly higher than that in serum of newborns delivered at 23-28 wk of gestation (63 ng/ml, n = 33). Umbilical cord serum levels of E3 were significantly higher among newborns delivered vaginally between 31.5 and 42 wk of gestation than among newborns delivered by cesarean section (p less than 0.005). Although serum E3 levels correlated highly (p less than 0.0001) to newborn weight throughout the entire period of gestation, there was no relationship of newborn weight to umbilical serum E3 levels within a given gestational period. Also, the umbilical serum levels of E3 in male infants were similar to those of female infants at each gestational age. Significant changes in umbilical serum levels of E3 as a function of gestational age were not observed among newborns (n = 90) who developed respiratory distress syndrome (RDS). The mean umbilical serum concentration of E3 in newborns delivered at 34.5-37 wk of gestation who developed RDS were significantly lower (p less than 0.01) than that in similar aged newborns whose lung function was normal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Association of development of chronic lung disease of newborns with neonatal colonization of Ureaplasma and cord blood interleukin‐8 level

Background: The aim of the present study was to investigate the association of chronic lung disease (CLD), neonatal Ureaplasma colonization, and interleukin‐8 (IL‐8) level of cord blood in preterm infants. Methods: In 77 infants of <32 weeks gestation, the relationship between IL‐8 level of cord blood, neonatal colonization of Ureaplasma, histological chorioamnionitis (CAM), and development of CLD was studied. Results: Five infants died and 29 infants developed CLD. The CLD group had significantly lower gestation (mean ± SD: 26.6 ± 1.8 weeks) compared with the infants without CLD (28.9 ± 1.9 weeks, P < 0.0001). Logistic analysis showed that the development of CLD was associated with gestational age (odds ratio [OR], 0.5; 95% confidence interval (CI): 0.4–0.8) and Ureaplasma colonization (OR, 4.1; 95%CI: 1.2–14.4). Ureaplasma colonization was also associated with CAM (OR, 6.5; 95%CI: 1.8–23.5), absence of respiratory distress syndrome (OR, 6.2; 95%CI: 1.3–30.5), and development of CLD (OR, 4.0; 95%CI: 1.1–15.3). Elevated cord blood IL‐8 ≥100 pg/mL was associated with female sex and the isolation of microorganisms (OR, 49.4; 95%CI: 4.6–525). Conclusion: The development of CLD defined by oxygen requirement at 36 weeks was associated with neonatal Ureaplasma colonization but not with IL‐8 level of cord blood. Elevated cord blood IL‐8 was associated with neonatal microorganisms isolation.     

Infection with Ureaplasma urealyticum and Mycoplasma hominis and the development of chronic lung disease in preterm infants

In a prospective cohort study in a tertiary referral neonatal intensive care unit, the endotracheal secretions of 40 consecutively intubated newborn infants, less than 31 weeks' gestation. were examined weekly for the genital mycoplasmas and all other common bacterial pathogens. Fifteen (37%) infants were positive for Ureaplasma urealyticum and/or Mycoplasma hominis. There were no differences in gestation, birthweight, use of surfactant, or time on ventilator between the culture-positive and negative babies. Thirteen (87%) of the culture-positive group developed chronic lung disease (CLD) compared with 11 (41%) of the negative group ( p = 0.0196). Of those culture-positive, 37% were not identified on the first specimen taken at the time of admission. These data suggest a significant association between infection with the urogenital mycoplasmas and CLD and also stress the need for repeated cultures to identify these organisms.     

Prediction of respiratory distress syndrome by the microbubble stability test on gastric aspirates in newborns of less than 32 weeks' gestation

AIM: There is a need for a rapid method to identify infants who will develop respiratory distress syndrome (RDS) soon after birth, to allow early treatment of affected infants with surfactant. The microbubble stability test (MST) may be one such method, but clinical experience is sparse. METHODS: The MST was performed on gastric aspirates from 188 infants with a mean gestational age of 29 (range 23-31) wk. RESULTS: 87 infants developed moderate to severe RDS, corresponding to a prevalence of 46%. The sensitivity, specificity and predictive values for identification of infants with moderate to severe RDS were determined for the average diameter of bubbles, the proportion of microbubbles with different diameters and the total number of microbubbles. The proportion of microbubbles with diameters <20 or 25 microm gave the best prediction, with a sensitivity of 78-79%, a specificity of 57-58%, a positive predictive value of 62% and a negative predictive value of 76%. Early treatment with nasal continuous positive airway pressure probably mitigated the development of RDS in some infants with a low-degree surfactant deficiency and this may explain the relatively low specificity. CONCLUSION: In infants of <32 wk gestation RDS can be predicted by computerized image analysis of the size distribution of microbubbles generated in gastric aspirates.     

Rehospitalization for respiratory syncytial virus infection in infants with extremely low gestational age or birthweight in Denmark

AIM: To determine the risk of rehospitalization for respiratory syncytial virus (RSV) infection during the first 2 y of life in extremely preterm infants. METHODS: Records on all rehospitalizations during the first 2 living years of all infants born with gestational age <28 wk or birthweight <1,000g during 1994 and 1995 in Denmark were retrospectively reviewed. RESULTS: Among 240 eligible infants, 43 (18%) had been rehospitalized 48 times owing to RSV. In infants (n = 210) without CLD the risk of rehospitalization for RSV was 16%, whereas in infants with CLD (n = 30) it was 30% (p = 0.065). Eighteen infants (38%) required respiratory support (supplemental oxygen only 3, continuous positive airway pressure 14, mechanical ventilation 1). Apart from CLD the only factor that could be associated with increased risk of hospitalization for RSV was discharge during autumn (p = 0.05). No infant died from RSV infection. CONCLUSION: The high rate of rehospitalization for RSV in extremely preterm infants in Denmark, especially in infants with CLD, should lead to considerations concerning more widespread use of prophylaxis against RSV in these infants.