Molecular evidence of Ureaplasma urealyticum and Ureaplasma parvum colonization in preterm infants during respiratory distress syndrome.
BACKGROUND
Ureaplasma urealyticum and U. parvum have been associated with respiratory diseases in premature newborns, but their role in the pathogenesis of the respiratory distress syndrome (RDS) is unclear. The aim of this study was to detect, using molecular techniques, the role of Mycoplasma spp. and Ureaplasma spp. in respiratory secretion and blood specimens of preterm newborns with or without RDS and to evaluate the prevalence of perinatal U. urealyticum or U. parvum infection. The influence of chemotherapy on the clinical course was also evaluated.


METHODS
Tracheal aspirate or nasopharingeal fluid samples from 50 preterm babies with (24) or without RDS (26) were analysed for detection of U. urealyticum and U. parvum by culture identification assay and PCR. Sequencing analysis of amplicons allowed us to verify the specificity of methods. Clarithromycin (10 mg kg-1 twice a day) was administered in ureaplasma-positive patients who presented clinical signs of RDS.


RESULTS
15/24 neonates with RDS (p < 0.001) and 4/26 without RDS were found PCR-positive for U. urealyticum or U. parvum. Culture identification assay was positive in 5/50 newborns, three of which with RDS. Sequencing analyses confirmed the specificity of these methods. Association of patent ductus arteriosus with ureaplasma colonization was more statistically significant (p = 0.0004) in patients with RDS than in those without RDS.


CONCLUSIONS
Colonization of the lower respiratory tract by Ureaplasma spp. and particularly by U. parvum in preterm newborns was related to RDS. The routine use of molecular methods could be useful to screen candidate babies for etiologic therapy.
Cultrera
Rosario
R
Infectious Diseases, Department of Clinical and Experimental Medicine, University of Ferrara, Ferrara, Italy. ctr@unife.it
Seraceni
Silva
S
Germani
Rossella
R
Contini
Carlo
C
D004269:DNA, Bacterial / Q000032:analysis / Q000097:blood; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000382:microbiology*; D019102:Infant, Very Low Birth Weight; D008297:Male; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012127:Respiratory Distress Syndrome, Newborn / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D014132:Trachea / Q000382:microbiology; D014509:Ureaplasma / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016869:Ureaplasma Infections / Q000382:microbiology*; D016990:Ureaplasma urealyticum / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S