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

Optimum Detection of Ureaplasma in Premature Infants

BACKGROUND

Ureaplasma spp. is a known risk factor for bronchopulmonary dysplasia in premature infants. Emerging research suggests treatment with azithromycin or clarithromycin in the first days of life (DOLs) reduces bronchopulmonary dysplasia in Ureaplasma spp. positive infants. Side effects of these antibiotics make it imperative to optimize reliable noninvasive screening procedures to identify infants who would benefit from treatment.

METHODS

The aim of this study was to determine the best site and time to screen for Ureaplasma spp. in 24- to 34-week premature infants. Oral, nasal, gastric and tracheal cultures were collected and placed immediately in 10B broth media. Polymerase chain reaction verified culture results and identified the Ureaplasma spp.

RESULTS

Cultures yielded a Ureaplasma spp. incidence of 80/168 = 47.6% [95% confidence interval (CI): 40-56]. Nasal cultures had greater sensitivity to detect Ureaplasma spp. than oral cultures (P = 0.008): however, a significant proportion of infants with Ureaplasma spp. would have been missed (12/79 = 15.2%, 95% CI: 8%-25%, P < 0.001) if oral cultures were not obtained. For all sites, the collection at DOL 7-10 were more likely to be positive than the collection at DOL 1-2: however, a significant proportion (5/77 = 6.5%, 95% CI: 2-15, P < 0.001) of infants with Ureaplasma spp. would have been missed if the DOL 1-2 cultures were not obtained.

CONCLUSIONS

For optimal Ureaplasma spp. detection in 24- to 34-week premature infants, cultures need to be taken both early and late in the first 10 DOLs both from nasal and oral secretions.

Association between pulmonary ureaplasma colonization and bronchopulmonary dysplasia in preterm infants: updated systematic review and meta-analysis

BACKGROUND

Previous meta-analyses have reported a significant association between pulmonary colonization with Ureaplasma and development of bronchopulmonary dysplasia (BPD). However, because few studies reporting oxygen dependency at 36 weeks corrected gestation were previously available, we updated the systematic review and meta-analyses to evaluate the association between presence of pulmonary Ureaplasma and development of BPD.

METHODS

Five databases were searched for articles reporting the incidence of BPD at 36 weeks postmenstrual age (BPD36) and/or BPD at 28 days of life (BPD28) in Ureaplasma colonized and noncolonized groups. Pooled estimates were produced using random effects meta-analysis. Meta-regression was used to assess the influence of difference in gestational age between the Ureaplasma-positive and Ureaplasma-negative groups. The effects of potential sources of heterogeneity were also investigated.

RESULTS

Of 39 studies included, 8 reported BPD36, 22 reported BPD28 and 9 reported both. The quality of studies was assessed as moderate to good. There was a significant association between Ureaplasma and development of BPD36 (odds ratio = 2.22; 95% confidence intervals: 1.42-3.47) and BPD28 (odds ratio = 3.04; 95% confidence intervals: 2.41-3.83). Sample size influenced the odds ratio, but no significant association was noted between BPD28 rates and difference in gestational age between Ureaplasma colonized and noncolonized infants (P = 0.96).

CONCLUSIONS

Pulmonary colonization with Ureaplasma continues to be significantly associated with development of BPD in preterm infants at both 36 weeks postmenstrual age and at 28 days of life. This association at BPD28 persists regardless of difference in gestational age.

The significance of Ureaplasma urealyticum as a pathogenic agent in the paediatric population

PURPOSE OF REVIEW

Ureaplasma urealyticum is a frequent commensal in the lower genital tract of sexually active women. It may be transmitted perinatally from the colonized mother to her offspring, often resulting in prematurity and neonatal disease. The microorganism also sustains a causative role for infectious diseases in older children.

RECENT FINDINGS

U. urealyticum infection can be diagnosed by culture, polymerase chain reaction, and the detection of specific antibodies. Neonatal infection has been implicated in various pathological conditions including pneumonia, chronic lung disease, central nervous system disorders, sepsis, osteomyelitis and even death. Older children may present with wheezing, pneumonitis, pertussis-like syndrome and different forms of arthritis. Large well-designed trials have demonstrated that the regular administration of antibiotics to vaginally colonized women are not beneficial in terms of preventing preterm labour. Macrolide-containing antibiotic regimens are, however, recommended for preterm premature rupture of the membranes. Erythromycin treatment of ureaplasma respiratory colonized premature infants shows no reduction in the incidence of chronic lung disease. Treatment of central nervous system infections, sepsis and arthritides includes tetracyclines, fluoroquinolones and anti-inflammatory agents, respectively.

SUMMARY

This review covers recent evidence concerning the role of U. urealyticum as a pathogen during childhood. It also includes an evaluation of contemporary diagnostic techniques and optimal therapeutic approaches.

Critical appraisal of the role of Ureaplasma in the development of bronchopulmonary dysplasia with metaanalytic techniques

BACKGROUND

Controversy exists over whether or not Ureaplasma colonization or infection of the respiratory tract contributes to the development of bronchopulmonary dysplasia (BPD). Because BPD is a major cause of morbidity and mortality in preterm infants and a potential therapeutic intervention with antimicrobials is possible, we sought to evaluate and critique the current medical literature and to document the reported association between Ureaplasma and BPD.

METHODS

We analyzed all peer-reviewed articles and previous reviews including cross-references that reported Ureaplasma respiratory tract colonization or infection and development of BPD in neonates published from January 1966 to December 2004. Inclusion criteria included a cohort limited to all neonatal intensive care unit admissions or all colonized infants, articles that did not define a numerator and a denominator for BPD and Ureaplasma or that included patients from other reports were excluded from the analysis. We evaluated BPD at 28 postnatal days (BPD28) or 36 weeks post-menstrual age (BPD36).

RESULTS

Twenty-three studies with an aggregate of 2216 infants reported BPD28, and 8 studies with 751 infants reported BPD36. Although there was significant association between Ureaplasma colonization and both BPD28 and BPD36, there was substantial heterogeneity (Q test statistic, P < 0.01). We therefore focused on describing the study characteristics associated with an increased relative proportion of BPD. The greatest contribution to effect was from the studies enrolling fewer than 100 infants.

CONCLUSION

Ureaplasma colonization is associated with higher reported rates of BPD, but the greatest reported effect is seen in small studies; reporting bias may be partially responsible for this effect.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

Ureaplasma urealyticum, Mycoplasma hominis et pathologiesnéonatales : Données personnelles et revue de la littérature

Ureaplasma urealyticum and Mycoplasma hominis colonized 20-40% of newborns and are more frequent in premature. They are responsible for localized infections such as pleural effusion, pneumopathy, adenopathy, abscess or systemic sepsis. An important hyperleukocytosis is often associated with pulmonary infections. Their responsibility, as pathogen agents, is questionable in some non bacterial meningitis. There is large controversy for their role as cofactor, in chronic lung disease (bronchopulmonary dysplasia) and periventricular leukomalacia, because of a too low number of newborns in prospective trials. Genital mycoplamas are resistant to beta lactamines. Macrolides have a good sensitivity, particularly josamycine, but Mycoplasma hominis is resistant to erythromycin. For systemic sepsis, fluoroquinolones such as ciprofloxacine have less deleterious effects than IV erythromycin.

Effects of antenatal colonization with ureaplasma urealyticum on pulmonary disease in the immature baboon

Current nonhuman models for bronchopulmonary dysplasia have not included perinatal infection. We studied the effects of antenatal Ureaplasma urealyticum (Uu) infection in the 125-d immature baboon. Ten 125-d gestation (term = 185 d) baboon dams were delivered after intra-amniotic inoculation with Uu. Serial blood and tracheal aspirate samples were analyzed for Uu colony-forming units, IL-6, IL-8, and cell counts. Physiologic parameters were serially recorded. Lung histology was examined after 14 d of ventilation and compared with unexposed controls. All Uu-exposed animals had >4 x 102 CFU in tracheal aspirate at 24 h. Four of nine Uu animals remained heavily colonized [(+) Uu] at necropsy (>6 x 103). Five animals had negative or low tracheal colony-forming units. All Uu animals had significant increases for white blood cells, IL-6, and IL-8 in amniotic and fetal lung fluid. Compared with controls, (+) Uu animals had significantly higher fraction of inspired oxygen, airway pressures, oxygenation index, and ventilation efficiency index between 48 and 240 h and had significantly elevated tracheal IL-6 and IL-8 concentrations between 72 and 240 h. Compared with controls (-) Uu animals had significantly better oxygenation index and ventilation efficiency index scores between 48 and 144 h. Lung histopathology in both Uu groups showed more severe bronchiolitis and interstitial pneumonitis compared with controls. Two patterns of disease were observed after Uu perinatal infection. Persistent colonization manifested a picture consistent with acute pneumonitis, worse lung function from 2 to 10 d, and prolonged elevated tracheal cytokines. Colonized animals that subsequently cleared Uu from the lung demonstrated early improved lung function compared with unexposed controls yet still manifested mixed bronchiolitis and interstitial pneumonitis at necropsy. Inherent immune system responses may determine outcome of perinatal Ureaplasma colonization.

Erythromycin for the prevention of chronic lung disease in intubated preterm infants at risk for, or colonized or infected with Ureaplasma urealyticum

BACKGROUND

Controversy exists over whether or not Ureaplasma urealyticum colonization or infection of the respiratory tract contributes to the severity of chronic lung disease (CLD), a major cause of morbidity and mortality in preterm infants.

OBJECTIVES

To evaluate the efficacy and safety of prophylactic or therapeutic erythromycin in preventing chronic lung disease in intubated preterm infants with unknown U. urealyticum status or proven positivity.

SEARCH STRATEGY

Searches were done of MEDLINE (1966-June 9, 2003), EMBASE (1980-May 5, 2003), The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2002), previous reviews including cross-references, and abstracts of conference proceedings (Pediatric Academic Societies 2000-2003, American Thoracic Society 2001-2003). There were no language restrictions. Expert informants were contacted.

SELECTION CRITERIA

Randomized or quasi-randomized studies comparing either prophylactic or therapeutic administration of oral or intravenous erythromycin (regardless of dose and duration) versus no treatment or placebo among intubated preterm infants <37 weeks and <2500 grams with either unknown U. urealyticum status or proven positivity by culture or polymerase chain reaction.

DATA COLLECTION AND ANALYSIS

Data were extracted by all of the authors independently and differences were resolved by consensus. Treatment effects for categorical outcomes were expressed as relative risk, with 95% confidence intervals.

MAIN RESULTS

Two small controlled studies, both involving intubated babies <30 weeks gestation, were eligible for inclusion. Lyon 1998 tested prophylactic erythromycin in babies whose U. urealyticum status was unknown at the time of initiation of treatment. Jonsson 1998 tested erythromycin in babies known to be culture positive for U. urealyticum. Neither trial showed a statistically significant effect of erythromycin on CLD, death or the combined outcome CLD or death. Because the two studies differed importantly in their design, the results were not combined in meta-analyses. No adverse effects of a 7-10 day course of erythromycin were reported in either study.

REVIEWER'S CONCLUSIONS

Current evidence does not demonstrate a reduction in CLD/death when intubated preterm infants are treated with erythromycin prophylactically before U. urealyticum culture/PCR results are known or when Ureaplasma colonized, intubated preterm infants are treated with erythromycin. However, a true benefit could easily have been missed with the small sample sizes in the two eligible studies. The studies were greatly underpowered to detect uncommon adverse effects such as pyloric stenosis. Additional controlled trials are required to determine whether antibiotic therapy of Ureaplasma reduces CLD and/or death in intubated preterm infants.