Neonatal jaundice is a physiological condition which has potentially deleterious outcomes. Elevated serum bilirubin levels are well-documented antioxidants and have been shown to disrupt cellular membranes of Gram-positive organisms under specific conditions. To determine whether bilirubin had antimicrobial potential against neonatal sepsis organisms, relevant isolates were identified by clinical audit and assessed for sensitivity. 26 clinical isolates including 15 CoNS, 7 GBS, E. coli, E. faecalis, K. oxytoca and A. haemolyticum were characterised biochemically, genetically, and by MALDI Biotype. GBS isolates showed a significant reduction in growth from 100–82.0%(±6.1%), between 0–400μM bilirubin– supplemented CBA (p=0.005). A physiologically relevant liquid model with 100μM bilirubin was developed to test growth reduction. Results showed slight growth reduction in isolates at specific time points, but species specific. Transcriptomic analysis was performed on three GBS isolates to determine effect of bilirubin exposure on gene expression. 17 genes were differentially expressed between 100μM bilirubin and solvent control; 16 up-regulated and one down-regulated with bilirubin. Most significantly, a 5 gene cluster describing multiple components of the phosphotransferase system and two ABC transporter genes were up-regulated, potentially to remove bilirubin from the cell. Proteomic analysis was completed to study protein expression: 12 proteins were identified by LC-MS from 2-DGE and Progenesis SameSpots analysis. Of these, 6 were up- and 6 down-regulated with bilirubin. Up-regulated proteins included two ABC transporter components, phosphoglycerate kinase, S-ribosylhomocysteinase, and two transcription regulators: GroEL/GntR. Down-regulated was iron ABC transporter, NeuB, ornithine carbamoyltransferase and ssDNA binding proteins controlling transcription and translation. This study concluded that bilirubin may play a protective role during the neonatal period; it can be considered an antimicrobial compound which disrupts Grampositive organisms such as GBS, an important agent in early-onset sepsis. The results from this study could be used to develop novel antimicrobial treatments based on identified molecular targets.

published_or_final_version / Paediatrics / Doctoral / Doctor of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Synchronous interaction between adolescent mothers with preterm infants in the Neonatal Intensive Care Unit was examined in this study. Understanding the characteristics of synchrony in adolescent mother and premature infant interactions during this early period in the development of the relationship provides direction for the development of nursing strategies to foster synchronous interaction in the neonatal intensive care unit (NICU) setting and, subsequently, positive developmental outcomes for preterm infants. The research design was a one-group, pretest-posttest, exploratory intervention assessing synchronous interaction using the Nursing Child Assessment Feeding Scale (NCAFS) among 27 adolescent mothers and their premature infants in the NICU. The study examined the differences in adolescent mother-premature infant interaction in the NICU environment prior to an intervention and within 48 hours after receiving the Preterm Infant Cues Intervention (PICI). Additional variables including stress, social support, age of the adolescent mother and preterm infant, ethnicity, length of stay in the NICU, and preterm infant weight were considered. Results showed a statistically significant difference between Time 1 and Time 2 synchronous interaction measurements indicating that the PICI may have resulted in the adolescent mother better understanding the preterm infant’s behavior. The Caregiver Total Scale score (t = -3.93, p < .001) and the Total Scale score (t = -3.96, p < .001) were the two main scales that the PICI could have affected. There were no correlations among the other independent variables and the dependant variable. Future research should focus on a large scale longitudinal study to measure synchronous interaction over multiple time points beginning in the NICU carrying through the first year of child development. Adding a qualitative component to future studies would provide further insight into experience of adolescent mothers with preterm infants. / text

Weight velocity of 34 Egyptian infants aged two to thirteen months was examined before, during, and after 43 diarrheal episodes. The study was conducted in Bolaq El Dakrour, a poor neighborhood in metropolitan Cairo, during the summer of 1990. Weight measurements, food intake, morbidity, and socio-demographic-economic-sanitary data were collected. Diarrhea was reported according to mothers' definitions. A local reference population was constructed based on the criteria that: infants were from the same neighborhood, of the same age and sex, and were reported diarrhea-free when study infants were reported sick. Weight velocity during diarrheal episodes was 16 g/d lower than before illness and 15 g/d lower than reference infants. One-month post-illness weight velocity was similar to pre-illness weight velocity, with no evidence of catch-up growth. Illness severity indices, namely the number of symptoms or illnesses experienced, number of stools/day, and presence of blood in stool were strong predictors of velocity during and one-month post-illness. Breastfeeding had a positive influence on weight velocity during illness. Consumption of rice, macaroni and vegetables was negatively associated with weight velocity during and one month after illness. Weight gain in the month following the episode was positively associated with a higher level of formal education and occupation of fathers, negatively with the presence of adults above 50 years of age in the household, and a greater age difference between the parents. Percent of time sick with fever had a negative impact on long-term weight velocity. Thus in this population, the effect of diarrhea on weight gain velocity is transient, catch-up growth does not occur, and infants fed solid food suffer the most weight loss. Thus, it is possible that effective nutritional intervention will reduce growth faltering.

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Factors that influence exclusive breastfeeding in Namibia are important, especially in light of the implementation of the Baby and Mother Friendly Initiative. Infant feeding practices, especially breastfeeding, are important public health issues, particularly in the prevention of HIV transmission from mother to child. This thesis determined the prevalence of exclusive breastfeeding and measures the association of demographic and service-related factors on exclusive and non-exclusive breastfeeding practices.