Arun K. Pramanik

Nosocomial Malassezia pachydermatis bloodstream infections in a neonatal intensive care unit

Malassezia pachydermatis, a lipophilic yeast, has been described to cause sporadic nosocomial bloodstream infections (BSI). Nosocomial outbreaks of M. pachydermatis BSI have never been described. A cluster of M. pachydermatis BSIs in the neonatal intensive care unit at Louisiana State University Medical Center, University Hospital provided the opportunity to investigate the epidemiology of this organism and apply molecular epidemiologic typing techniques. A case-patient was defined as any neonatal intensive care unit patient in University Hospital with a blood culture positive for M. pachydermatis from January 1, 1989, through August 15, 1991. Five patients met the case definition. Case-patients were premature as estimated by gestational age and required prolonged hospitalization. Case-patients received parenteral nutrition and intravenous lipids for twice as many days as randomly selected controls. No environmental source of M. pachydermatis was identified; however, infants on each side of a previously identified M. pachydermatis-colonized infant became colonized with M. pachydermatis during a 20-day period. Chromosomal analysis of five M. pachydermatis blood isolates from two case-patients had identical banding patterns. These data show that M. pachydermatis can cause nosocomial BSI outbreaks, that premature infants receiving parenteral nutrition and/or lipids may be at greatest risk and that transmission is most likely from person to person, probably via the hands of medical personnel.

Candida parapsilosis bloodstream infections in neonatal intensive care unit patients : epidemiologic and laboratory confirmation of a common source outbreak

BACKGROUND Candida parapsilosis is a common cause of sporadic and epidemic infections in neonatal intensive care units (NICUs). When a cluster of C. parapsilosis bloodstream infections occurred in NICU patients in a hospital in Louisiana, it provided us with the opportunity to conduct an epidemiologic investigation and to apply newly developed molecular typing techniques. METHODS A case-patient was defined as any NICU patient at Louisiana State University Medical Center, University Hospital, with a blood culture positive for C. parapsilosis during July 20 to 27, 1991. To identify risk factors for C. parapsilosis bloodstream infection, a cohort study of all NICU infants admitted during July 17 to 27, 1991, was performed. Electrophoretic karyotyping was used to assess the relatedness of C. parapsilosis isolates. RESULTS The receipt of liquid glycerin given as a suppository was identified as a risk factor (relative risk, 31.2; 95% confidence intervals, 4.3 to 226.8). Glycerin was supplied to the NICU in a 16-oz multidose bottle. Bottles used at the time of the outbreak were not available for culture. All six available isolates from four case-patients had identical chromosomal banding patterns; six University Hospital non-outbreak isolates had different banding patterns. CONCLUSIONS This study demonstrates the utility of combined epidemiologic and laboratory techniques in identifying a novel common source for a C. parapsilosis bloodstream infection outbreak and illustrates that extreme caution should be exercised when using multidose medications in more than one patient.

Genomic heterogeneity in the yeast Candida parapsilosis

Candida parapsilosis shows a wide intraspecies variation in chromosome/homolog size distribution. As a prerequisite for delineating modes of transmission, we have undertaken an analysis of genetic variation at different levels. In the present study we have observed that a majority of isolates display similar electrophoretic karyotype patterns consistent for the species, with variations in the smaller group of chromosomes. In two strains we observed phenotypic “switching”; one of these also exhibited a mixed karyotypic subpopulation. In contrast, a few isolates displayed a greater degree of chromosome/ homolog size variation. We also observed, through randomly amplified polymorphic DNA (RAPD) analysis, results consistent with those of pulsed-field electrophoresis. Isolates displaying a high degree of chromosome/homolog variation also displayed a high degree of variation in genomic “fingerprints”. Polymorphisms, although present, were much reduced in the majority of isolates. These parallel observations suggest a common underlying mechanism. Our results are consistent with the hypothesis that chromosome-sized variations in C. parapsilosis are due to random genetic events. A similar mechanism has been hypothesized for the taxonomically related yeast Candida albicans.

Surfactant replacement therapy for pulmonary diseases.

Surfactant therapy has clearly been a meaningful addition to the therapeutic armamentarium in the management of premature infants with RDS. Pediatricians and others involved in the care of newborn infants should familiarize themselves with the various surfactant preparations, the indications for their use, the techniques of administration, and the possible side effects. All such care provides should also be skilled in endotracheal intubation and ventilation of neonates; recognition of the clinical and radiographic signs of RDS; and have the appropriate equipment to monitor cardiopulmonary status, oxygenation, and ventilation in these infants until transport to a tertiary care facility can be accomplished. In addition to the two current FDA-approved surfactants, several other surfactants are in various stages of evaluation. When administered to infants with established RDS, both natural and synthetic surfactants have clearly been shown to improve survival, decrease requirements for ventilatory support, and reduce the incidence of air leak complications. Although by no means conclusively demonstrated, certain infants, particularly those delivered at < 30 week gestation, may benefit from immediate treatment in the delivery room. It should be emphasized that, except under extenuating but controlled circumstances and except in the hands of an experienced physician, surfactant treatment should not be viewed as an integral part of neonatal resuscitation. Adequate treatment requires the administration of a minimum of two surfactant doses, although some infants may benefit from additional doses or treatment with an alternative preparation. Massive pulmonary hemorrhage, although rare, is observed with prophylactic and rescue treatment protocols and may result from hemorrhagic pulmonary edema due to a hemodynamically significant PDA. Currently there are no data to recommend the use of one surfactant preparation over another. The short- and long-term benefits may be similar with different products. Therefore, we must await results of trials with then necessary power (large number of subjects) and unbiased design to discern any clinically relevant differences. Results of studies directly comparing the relative efficacy of Survanta and Exosurf, conducted under the auspices of the National Institutes of Health, are expected in 1993. Multicenter trials comparing prophylactic and rescue administration of Exosurf versus CLSE and Survanta versus CLSE are currently underway. It is encouraging to note that follow-up studies up to 2 years of age do not reveal an increase in physical or neurodevelopmental handicaps, BPD, or other problems in preterm infants who received surfactant preparations either for prophylaxis or rescue therapy. Results of long-term follow-up studies, however, are not yet available.(ABSTRACT TRUNCATED AT 400 WORDS)

Electron microscopic evaluation of bacterial adherence to polyvinyl chloride endotracheal tubes used in neonates

Studies in adults suggest a possible association between pulmonary nosocomial infection and bacterial adherence to endotracheal tubes (ETT). Some strains of coagulase-negative Staphylococcus produce a mucoid extracellular material known as slime or glycocalyx that helps bacteria adhere to the surface of biomaterials. We examined by scanning and transmission electron microscope the surface of 29 polyvinyl ETT removed from neonatal patients, and ten unused ETT. Multiple surface irregularities were found in the unused tubes. These irregularities were most prominent in the tip and around the side hole. Amorphous material containing slime-producing bacteria was found on 29 ETT removed from patients. Tubes in place for longer times had greater areas of surface covered; the amorphous material was more concentrated in the areas where surface irregularities were most prominent. No clinical correlation with pulmonary noscomial infection was established.

Endothelial nitric oxide synthase genotypes in the etiology of retinopathy of prematurity in premature infants

Purpose: Retinopathy of Prematurity (ROP) is a vasoproliferative disorder affecting preterm infants leading to visual impairment. ROP is more common in Caucasians than African Americans. Very low birth weight infants have immature retinas and are susceptible to ROP. Because of differences in individual responses to the treatment, various genetic factors have been looked into to understand the etiology of ROP. Endothelial nitric oxide (eNO) serves as a vasodilator, relaxes smooth muscle, prevents platelet aggregation, and facilitates improved blood flow and vascular tonicity. Mutant eNO synthase (eNOS) genotypes result in reduced nitric oxide levels by decreasing enzyme activity. Since eNO affects vasculature and ROP is a vascular disease, the present investigation was aimed at studying the association of genotypes with ROP. Methods: Two eNOS gene single nucleotide polymorphisms (SNPs) (T-786C, and G894T) were studied by microplate-Restriction Fragment Length Polymorphism Polymerase Chain Reaction (RFLP PCR) method. Genotypes were studied in 146 premature infants. Results: The present data showed significant differences in the baseline gene frequencies between Caucasians and African Americans. ROP patients displayed 3-fold higher frequencies of mutant -786C and 894T alleles in both ethnicities compared to respective controls. Conclusions: The present data suggest ethnic stratification of genotypes. Mutant -786C and 894T alleles are significant risk factors in the development of ROP, and suggest a strong association between eNOS polymorphisms and the disease. It is interesting to know if a larger dataset of ROP patients can confirm our initial findings.

Neonatal necrotizing enterocolitis: Clinical challenges, pathophysiology and management.

NEC remains a major concern for neonatologists, surgeons, and gastroenterologists due to its high morbidity and mortality. These infants often have poor developmental outcome, and contribute to significant economic burden resulting in marked stress in these families. By developing and adhering to strict feeding protocols, encouraging human milk feeding preferably from the infants mother, use of probiotics, judicious antibiotic use, instituting blood transfusion protocols, the occurrence of NEC may possibly be reduced. However, because of its multifactorial etiology, it cannot be completely eradicated in the NICUs, particularly in the extremely premature infants. Ongoing surveillance of NEC and quality improvement projects may be beneficial.

Neonatal respiratory distress: a practical approach to its diagnosis and management.

Respiratory disorders are the most frequent cause of admission to the special care nursery both in term and preterm infants. Pediatricians and primary care providers may encounter newborn infants with respiratory distress in their office, emergency room, delivery room, or during physical assessment in the newborn nursery. The authors have proposed a practical approach to diagnose and manage such infants with suggestions for consulting a neonatologist at a regional center. Their objective is that practicing pediatricians should be able to assess and stabilize such infants, and transfer to or consult a neonatologist, cardiologist, or pulmonologist after reading this article.

Elevated acetoacetate and monocyte chemotactic protein-1 levels in cord blood of infants of diabetic mothers.

Background: Infants of diabetic mothers (IDMs) are at increased risk for metabolic complications. Type 1 and some type 2 diabetic patients have elevated levels of the ketone bodies acetoacetate (AA) and β-hydroxybutyrate (BHB). Objective: The aim of this study was to examine how hyperketonemia in diabetic mothers affects markers of inflammation and oxidative stress in their offspring. Methods: Blood was obtained from 23 diabetic mothers and 13 healthy mothers and their infants’ umbilical cords at delivery. Interleukin-8, monocyte chemotactic protein-1 (MCP-1) and protein carbonyl (protein oxidation) levels were determined by ELISA. U937 human monocyte cell culture was used to examine the effect of AA and BHB on secretion of MCP-1. Results: There was a significant increase in the levels of AA in cord blood of IDMs compared with cord blood of infants of healthy mothers. A significant increase in the levels of protein oxidation (p < 0.05) and MCP-1 levels (p < 0.05) was observed in the cord blood of IDMs. The level of MCP-1 correlated significantly (r = 0.51, p = 0.01) with the concentration of AA in the IDMs. In further experiments with cultured monocytes treated with exogenous AA (0–4 mM), a significant increase in MCP-1 secretion was observed in AA- but not BHB-treated monocytes. Conclusion: Blood levels of AA and MCP-1 are elevated in IDMs, which may contribute to the development of the metabolic complications seen in IDMs.

Effect of Placental Transfusion on the Blood Volume and Clinical Outcome of Infants Born by Cesarean Section

Delay in cord clamping up to 30 to 40 seconds is feasible and should be practiced in preterm and term infants born by cesarean section. In term infants, this maneuver may decrease iron deficiency anemia at 6 months of age. Premature infants may have a higher blood volume and hematocrit initially requiring fewer transfusions. They also have a decreased incidence of intraventricular hemorrhage. The effect of compounding factors, such as maternal blood pressure, uterine contraction, medications, bleeding, and their effects on the infants immediate and long-term outcome are unclear.