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Background: Cytomegalovirus (CMV) is the most frequently contracted virus in preterm infants. Postnatal infection is mostly asymptomatic but is sometimes associated with severe disease. To diagnose an infection, urine or saliva samples can be tested for CMV-DNA by real-time polymerase chain reaction (rtPCR). Although the diagnostic accuracy of testing saliva samples has not been determined in preterm infants, saliva is widely used because it is easier to obtain than urine. Objectives: To determine whether screening of saliva is equivalent to urine to detect a postnatal CMV infection in preterm infants. Study design: Between 2010 and 2013 saliva and urine samples were collected from infants admitted to the Neonatal Intensive Care Unit of the University Medical Center Utrecht and born with a gestational age (GA) below 32 weeks. Urine samples were obtained within three weeks after birth and urine and saliva samples at term equivalent age (40 weeks GA) and tested for CMV-DNA by rtPCR. Infants with a congenital CMV infection were excluded. Results: Of 261 preterm infants included in the study, CMV-DNA was detected in urine of 47 and in saliva of 43 children. Of 47 infants with postnatal CMV infection, CMV was detected in 42 saliva samples (sensitivity 89.4%; CI 76.9-96.5). Of 214 children without postnatal CMV infection, one saliva sample tested positive for CMV (specificity 99.5%; CI 97.4-99.9). Conclusions: Screening saliva for CMV-DNA by rtPCR is inferior to urine to diagnose postnatal CMV infections in preterm infants. [ABSTRACT FROM AUTHOR]

Ureaplasma infection of the amniotic cavity is associated with adverse postnatal intestinal outcomes. We tested whether interleukin-1 (IL-1) signaling underlies intestinal pathology following ureaplasma exposure in fetal sheep. Pregnant ewes received intra-amniotic injections of ureaplasma or culture media for controls at 3, 7, and 14 d before preterm delivery at 124 d gestation (term 150 d). Intra-amniotic injections of recombinant human interleukin IL-1 receptor antagonist (rhIL-1ra) or saline for controls were given 3 h before and every 2 d after Ureaplasma injection. Ureaplasma exposure caused fetal gut inflammation within 7 d with damaged villus epithelium and gut barrier loss. Proliferation, differentiation, and maturation of enterocytes were significantly reduced after 7 d of ureaplasma exposure, leading to severe villus atrophy at 14 d. Inflammation, impaired development and villus atrophy of the fetal gut was largely prevented by intra-uterine rhIL-1ra treatment. These data form the basis for a clinical understanding of the role of ureaplasma in postnatal intestinal pathologies. [ABSTRACT FROM AUTHOR]

Studies suggest that infection with highly prevalent Pseudomonas aeruginosa clones in cystic fibrosis (CF) is associated with an unfavourable clinical outcome. We studied the clinical characteristics of patients infected with a recently described, highly prevalent P. aeruginosa clone (ST406) in two CF centres in The Netherlands. Multilocus sequence typing data were available for 219 patients, of whom 40 (18.3%) were infected with ST406 and 179 with other sequence types. ST406 infection was independently associated with age, having a sibling with ST406 infection and use of inhaled antibiotics, but not with unfavourable clinical outcome, suggesting that high transmissibility is not necessarily associated with high virulence. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a pathogen that often infects patients who are either immunocompromised or have local defects in host defences. It is known that cystic fibrosis (CF) patients are sometimes infected with certain clonal isolates. It is not clear whether these clonal isolates also infect non-CF patients and whether clonality of isolates occurs in other patient groups. The aim of this study was to investigate P. aeruginosa diversity and the occurrence of clones within five distinct paediatric patient groups susceptible to P. aeruginosa infection. P. aeruginosa isolates were cultured from 157 patients (CF first infection (CF-1 group) (29); CF chronic infection (CF-chronic group) (27); urinary tract infection (34); chronic suppurative otitis media (43); and intensive-care hospitalization/immunodeficiency (24)). All 202 phenotypically different isolates were tested for antimicrobial resistance and further typed by pulsed-field gel electrophoresis. Simpson’s diversity index was calculated for the five groups. CF-chronic patients carried the highest number of distinct P. aeruginosa phenotypes and genotypes per culture. Isolates from the CF-chronic group were significantly less diverse than those from the other groups. A group of clonal isolates was observed among patients from the CF-chronic and CF-1 groups. These or different clonal isolates were not encountered among the three other patient groups. No characteristic resistance pattern could be identified among isolates from the distinct patient groups and among the clonal isolates. In conclusion, isolates of the CF-chronic group were less diverse than those in the other patient groups with P. aeruginosa infection; clonal isolates were not encountered in non-CF patients. Transmission of clonal CF isolates to other patient groups was not observed. [ABSTRACT FROM AUTHOR]

Clin Microbiol Infect 2010; 16: 488–490 Transmission of respiratory syncytial virus (RSV) from children with lower respiratory tract infection (LRTI) at a paediatric intensive-care unit (PICU) was examined using a highly sensitive real-time PCR. Twenty-four children with RSV LRTI were admitted during the study period (total days of potential transmission: 239). Forty-eight RSV-negative patients were followed up for RSV acquisition every 5 days (total days of exposure: 683). No single RSV transmission was documented with this highly sensitive diagnostic method. Therefore, routine infection control measures of LRTI patients seem to be adequate to prevent RSV transmission at the PICU. [ABSTRACT FROM AUTHOR]

Clin Microbiol Infect 2012; 18: 567-574 Abstract Despite intensive eradication therapy, some CF patients with early Pseudomonas aeruginosa infection rapidly develop a chronic infection. To elucidate factors associated with this persistence, bacterial characteristics of early P. aeruginosa isolates were analysed that were either eradicated rapidly or persisted despite multiple antimicrobial treatments. Eighty-six early infection episodes were studied. First P. aeruginosa isolates from patients with eradication (36) or persistent infection (16) were included; isolates from patients with intermittent infection (34) were omitted from the study. Virulence assays, antimicrobial resistance, cytotoxicity and mutation frequencies were analysed in vitro. P. aeruginosa was genotyped by SNP-array. Transcriptomic profiles of two eradicated and two persistent strains were compared. Nineteen per cent of patients developed persistent infection; 42% achieved eradication. Secretion of virulence factors and mutation frequencies were highly variable among both eradicated and persistent isolates and were not different between the groups. Cytotoxicity was present in 57% of eradicated vs. 100% of persistent isolates (p <0.01). None of the isolates were resistant to antibiotics. The isolates were genotypically highly diverse. Multivariate analysis showed that in vitro determined bacterial characteristics could not predict persistence after first P. aeruginosa infection. Preliminary transcriptomic data showed increased expression of some genes related to a metabolic pathway. The early onset of chronic infection was not associated with ( in vitro determined) bacterial characteristics only. Although the persistent isolates were more often cytotoxic, for the individual patient it was not possible to predict the risk of persistence based on bacterial characteristics. Unknown factors such as host-pathogen and pathogen-pathogen interactions should be further explored. [ABSTRACT FROM AUTHOR]

Clin Microbiol Infect 2011; 17: 1381-1386 Abstract Aspergillus fumigatus is commonly found in the respiratory secretions of patients with cystic fibrosis (CF). Although allergic bronchopulmonary aspergillosis (ABPA) is associated with deterioration of lung function, the effects of A. fumigatus colonization on lung function in the absence of ABPA are not clear. This study was performed in 259 adults and children with CF, without ABPA. A. fumigatus colonization was defined as positivity of >50% of respiratory cultures in a given year. A cross-sectional analysis was performed to study clinical characteristics associated with A. fumigatus colonization. A retrospective cohort analysis was performed to study the effect of A. fumigatus colonization on lung function observed between 2002 and 2007. Longitudinal data were analysed with a linear mixed model. Sixty-one of 259 patients were at least intermittently colonized with A. fumigatus. An association was found between A. fumigatus colonization and increased age and use of inhaled antibiotics. In the longitudinal analysis, 163 patients were grouped according to duration of colonization. After adjustment for confounders, there was no significant difference in lung function between patients colonized for 0 or 1 year and patients with 2-3 or more than 3 years of colonization (p 0.40 and p 0.64) throughout the study. There was no significant difference in lung function decline between groups. Although colonization with A. fumigatus is more commonly found in patients with more severe lung disease and increased treatment burden, it is not independently associated with lower lung function or more severe lung function decline over a 5-year period. [ABSTRACT FROM AUTHOR]