Neonatal mortality and morbidity in extremely preterm small for gestational age infants: a population based study.

AIM: To assess if growth restricted (small for gestational age, SGA) extremely preterm infants have excess neonatal mortality and morbidity. METHODS: This was a cohort study of all infants born alive at 22-27 weeks' post menstrual age in Norway during 1999-2000. Outcomes were compared between those who were SGA, defined as a birth weight less than the fifth percentile for post menstrual age, and those who had weights at or above the fifth percentile. RESULTS: Of 365 infants with a post menstrual age of <28 weeks, 31 (8%) were SGA. Among infants with a post menstrual age of <28 weeks, only chronic lung disease was associated with SGA status (OR 2.7, 95% CI 1.0 to 7.2). SGA infants with a post menstrual age of 26-27 weeks had excess neonatal mortality (OR 3.8, 95% CI 1.3 to 11), chronic lung disease and a significantly higher mean number of days (age) before tolerating full enteral nutrition. SGA infants with a post menstrual age of 22-25 weeks had an excess risk of necrotising enterocolitis. CONCLUSION: Extremely preterm SGA infants had excess neonatal mortality and morbidity in terms of necrotising enterocolitis and chronic lung disease.

Persistent strains of coagulase-negative staphylococci in a neonatal intensive care unit: virulence factors and invasiveness.

Coagulase-negative staphylococci (CoNS) are the major cause of nosocomial bacteraemia in neonates. The aim of this study was to investigate whether persistent strains of CoNS possess specific bacterial characteristics as compared with sporadic non-cluster isolates. In total, 180 blood culture isolates (95 contaminants and 85 invasive isolates) obtained from a single neonatal unit over a 12-year period were studied. Pulsed-field gel electrophoresis (PFGE) identified 87 persistent CoNS strains (endemic clones). The two largest PFGE clusters belonged to a single clonal complex according to multilocus sequence typing. Patients colonised or infected with endemic clones were of lower gestational age than those infected with non-cluster strains. One Staphylococcus haemolyticus cluster appeared to selectively colonise and infect the most extreme pre-term infants. Endemic clones were characterised by high levels of antibiotic resistance and biofilm formation. All 51 isolates belonging to the two largest PFGE clusters were ica operon-positive. Genes encoding Staphylococcus epidermidis surface protein B and the production of phenol-soluble modulins (PSMs) were also more prevalent among endemic clones than among non-cluster strains. However, endemic clones were not more prevalent among invasive isolates than among contaminants. These findings indicate that multiple selective factors, including antibiotic resistance, biofilm formation, surface proteins with adhesive properties, and PSMs regulated by agr, increase the ability of CoNS to persist in a hospital environment. It may be more prudent, when searching for new therapeutic targets, to focus on ubiquitous components of CoNS instead of putative virulence factors that do not clearly contribute to increased invasive capacity.

Fat-soluble vitamins in breast-fed preterm and term infants.

OBJECTIVE: To examine the supply and status of fat-soluble vitamins in very low birth weight (VLBW) infants compared to a reference group of normal birth weight (NBW) infants. DESIGN: A longitudinal study of VLBW infants in the early neonatal period. Blood samples were drawn at 1 week of age and at discharge from hospital. Plasma was analyzed for the fat-soluble vitamins: retinol, 25-OH-vitamin D, alpha-tocopherol and phylloquinone (vitamin K(1)) using high-performance liquid chromatography. SUBJECTS: A total of 40 VLBW infants were included in the study. A reference group of 33 NBW infants was randomly selected from one of our previous studies. RESULTS: The VLBW infants received fortified human milk, and daily oral vitamin supplement (Multibionta). In VLBW infants, plasma retinol concentrations decreased and plasma 25-OH-vitamin D increased during the study period. VLBW infants had significantly lower plasma retinol (0.3 vs 0.7 mu M) and higher plasma 25-OH-vitamin D (166 vs 25 nM) at discharge compared to NBW infants. Plasma phylloquinone concentration in VLBW infants was very high (53 ng/ml) at one week of age, especially in the youngest infants (192 ng/ml), but decreased rapidly during the study period resulting in low/normal plasma concentrations (0.9 ng/ml) at discharge. CONCLUSIONS: We observed alterations in plasma concentration of retinol and 25-OH-vitamin D in VLBW infants in the early neonatal period, resulting in marked differences between VLBW at discharge and NBW. Further trials are needed to evaluate whether changes in vitamin supplementation may improve clinical outcome in VLBW infants.

C-reactive protein (CRP) response patterns in neonatal septicaemia.

C-reactive protein (CRP) is an unreliable diagnostic tool in the early diagnosis of neonatal septicaemia. However, serial measurements have been shown to be useful in monitoring the effectiveness of treatment. The aim of the present study was to investigate whether a specific CRP response pattern to different groups of pathogens could be identified during treatment of neonatal septicaemia. Serial CRP measurements from day 1 to 4 in monomicrobial blood culture-proven episodes of septicaemia were reviewed. In 4416 admissions, 180 out of 206 positive blood cultures were monomicrobial; 121 monomicrobial septic episodes were eligible for final analysis of the CRP response during treatment. A low median (M) value (day 1 to 4) was identified in coagulase-negative staphylococci (CONS) (M=23 mg/l), contrasting with high median values in Staphylococcus aureus (M=58 mg/l), group B streptococci (M=51 mg/l), Escherichia coli (M=51 mg/l) and Candida species (M=76 mg/l) (p<0.001). Median CRP values in the two groups were different for each of the treatment days 1 to 4 (p<0.001). An increase (p<0.001) in CRP during the 24 h before initiation of treatment was a sign of late-onset CONS septicaemia. In episodes where antimicrobial treatment failed, CRP levels were moderately elevated the day prior to treatment start and increased continuously thereafter, whereas successful treatment was generally accompanied by a decline in CRP in less than 4 days. The CRP response to CONS is significantly less pronounced than to other commonly encountered pathogens in neonatal septicaemia. A rise in CRP beyond the third day of empirical treatment should give rise to a suspicion of fungal infection or ineffective antibacterial treatment.

Antibiotic susceptibility of blood culture isolates after nearly two decades with netilmicin and ampicillin in neonatal septicaemia.

The aim of the study was to investigate the in vitro antibiotic susceptibility of blood culture isolates after almost 20 years with ampicillin and methicillin as empirical treatment for neonatal septicaemia. All blood culture isolates and their antibiograms obtained in a single tertiary neonatal intensive care unit from 1 January 1989 to 31 December 1994 were reviewed. Two hundred and six blood cultures from 181 infants containing 223 bacterial and 11 fungal isolates were identified during 4416 admissions. Fifteen (6.7%) of the bacterial isolates were resistant to ampicillin and netilmicin. Fourteen per cent of the staphylococcal spp. were susceptible to penicillin while more than 90% were susceptible to netilmicin. The coagulase-negative staphylococci (CONS) were resistant to netilmicin, methicillin and gentamicin in 12%, 49% and 65%, respectively. Eighty-nine per cent of the methicillin-resistant CONS were susceptible to netilmicin as opposed to 17% to gentamicin (p<0.001). Except for one strain of Acinetobacter sp., all Gram-negative bacteria were susceptible to netilmicin. Our data show that the ampicillin-netilmicin combination still provides a high in vitro coverage (93%) against bacteria identified in blood cultures from newborns in our unit. Netilmicin has a significantly better in vitro effectiveness against CONS than gentamicin.

Blood culture isolates during 6 years in a tertiary neonatal intensive care unit.

Blood culture results obtained in a single tertiary neonatal intensive care unit are reviewed. In 4416 admissions occurring over 6 y we identified 206 positive cultures (4.7/100 admissions) growing 234 bacterial and fungal isolates in 182 infants. Very early and early onset positive cultures comprised 17% and 22% each. Gram-positive bacteria dominated in very early (61%), early (91%) and late onset (78%) cultures with coagulase-negative staphylococci (CONS) as the most frequent isolate in all groups (22%, 46% and 55%, respectively). The 3 most frequent isolates following CONS were in very early onset cultures Escherichia coli (19%), anaerobic bacteria (17%) and group B streptococci (GBS) (14%), in early onset cultures Staphylococcus aureus (28%), Enterococci (7%), E. coli (6%) and Viridans streptococci (6%) and in late onset cultures S. aureus (15%), Candida species (8%) and E. coli (5%). Infants < or = 999 g birthweight, representing 6% of the admissions, contracted 37% of the positive blood cultures and nearly half (44%) of the CONS isolates. In these patients, a significant increase (p < 0.001) in the number of positive cultures/100 admissions and in the proportion of positive cultures in conjunction with an intravascular catheter were seen (p < 0.001). An intravascular catheter was more often present when CONS were isolated as compared to other organisms (p < 0.05). 23 positive cultures (11.2%), most frequently E. coli, were associated with a fatal outcome. Our microbiological pattern is dominated by a gram-positive flora, which is in agreement with recent European and North American reports, but differs from earlier Scandinavian studies in the proportion of CONS and GBS reported.

Enhancement of erythropoiesis by erythropoietin, bovine protein and energy fortified mother's milk during anaemia of prematurity.

Twenty-four premature infants, < 32 weeks gestational age, were randomly assigned in a double-blind, placebo-controlled trial to 6 weeks of treatment with either recombinant human erythropoietin (rHuEpo) 150 U/kg three times per week given sc (n = 12) or placebo (n = 12). The infants were fed a diet rich in protein (3.2 g/kg/day) and energy (130 kcal/kg/day) based on their own mother's milk fortified with bovine protein together with moderate iron supplementation (4 mg/kg/day). During the treatment (rHuEpo versus placebo) significant differences in mean (+/- SD) reticulocyte count (4.8 +/- 1.2 versus 2.7 +/- 1.4%; p < 0.01), mean packed red cell volume (PCV) (0.38 +/- 0.03 versus 0.34 +/- 0.04, p < 0.05) and mean haemoglobin concentration (12.6 +/- 1.1 versus 11.5 +/- 1.2 g/100 ml; p < 0.05) were found. Within the rHuEpo group, PCV and haemoglobin concentration remained unaltered from entry to 1 week after cessation of treatment whereas a significant decline was observed in the placebo group. No indications of iron deficiency were seen. We conclude that moderate doses of rHuEpo given to infants fed a diet rich in protein and energy are effective in ameliorating anaemia of prematurity. High iron supplementation does not seem to be essential for a significant erythropoietic response. No adverse effect attributable to rHuEpo was observed.

Photobiological properties of hematoporphyrin diesters: evaluation for possible application in photochemotherapy of cancer.

The dimethyl, diethyl, dipropyl, dibutyl, diamyl, dihexyl and diheptyl esters of hematoporphyrin (Hp) were synthesized and shown to be more strongly retained on a reverse phase (C18) high performance liquid chromatography column than most components of Photofrin II (PII) - the sensitizer used for photochemical treatment of cancer in the clinic. The Hp diesters were found to be less efficient than PII in sensitizing cells to photoinactivation. This was partly due to de-esterification of the Hp diesters by esterase activity in the serum. The de-esterification of the Hp diesters was highly dependent on the ester group, with Hp dimethyl ester (t1/2 for conversion to Hp monomethyl ester was 6 min) being de-esterified with a rate 500 times faster than that for Hp diheptyl ester. Incubation of NHIK 3025 cells with these dyes showed that the Hp diesters were all partly located in extranuclear spots and partly diffusely distributed in the cytoplasm. The fluorescing spots may be due to lysosomally located Hp diesters, since the lysosomal marker enzyme beta-Nacetyl-D-glucosaminidase was partly inactivated by Hp diesters and light.

Preparation and photosensitizing properties of hematoporphyrin ethers.

Hematoporphyrin ethers having acyl or aryl substituents in the 2 and 4 positions of the porphyrin ring have been synthesized, starting from protoporphyrin HBr adduct, and tested for photosensitizing efficiency on cells in vitro and transplanted tumors in mice. In general, they resemble the tumor localizing fraction of hematoporphyrin derivative (Hpd). Cellular uptake and retention runs parallel with the degree of their non-polarity and in vitro sensitizing efficiencies are up to ten times that of Hpd or Photofrin II (P II). They have high quantum yields for inactivation of cells and also relatively low in vivo skin/tumor concentration ratios.

Hematoporphyrin ethers--II. Improvements in method, synthesis of the dihexyl, dicyclohexanyl and diphenyl ethers and their preliminary biological evaluation.

1. Hematoporphyrin 2.4-dihexyl, -dicyclohexanyl and -diphenyl ethers have been synthesized. 2. Their chemical and physical properties are recorded. The possibility of isomerism is discussed. 3. Preliminary tests have indicated that they possess high photosensitizing efficiency on human cancer cells.