Molecular-epidemiologic study on outbreak of colonization by extended spectrum beta-lactamase producing Klebsiella pneumoniae in neonatal intensive care unit / 소아과

PURPOSE: The aims of this study included assessment of molecular-epidemiologic features during an outbreak of colonization of extended spectrum beta-lactamase producing Klebsiella pneumoniae(ESBL-KPN) and re-evaluation of their colonized status one year later. METHODS: Rectal swab cultures for ESBL-KPN from all hospitalized infants and newly admitted infants were obtained during the outbreak of colonization from July to December, 2000. The pattern of XbaI-digested chromosomal DNA of isolates were analyzed by pulsed-field gel electrophoresis. Weekly rectal swab cultures were obtained during the outbreak until patients were either discharged or decolonized. Patients discharged after being colonized had follow up stool cultures a year later. RESULTS: A total of 80 patients(28.5 percent) were colonized. Of those, 53 whose pulsed-field gel electrophoresis(PFGE) was possible only once, were ESBL-KPN grouped into six cluster clones and 10 single clones:28 patients(52.8 percent) were colonized with type A, the most common clone, followed by type B in 11 patients(20.8 percent). Of those 12 patients in whom serial PFGE was done more than twice, type A was predominant. Narrowed-down in strains occurred from types A, B, C, D and three single clones at initiation of the study into types A and type B after three months of strict infection control. Among 75 patients(93.7 percent) who were sent home after being colonized, 30 patients were re-called for stool cultures a year later:All of them were decolonized. CONCLUSION: This study demonstrates the importance of infection control as the diversity of ESBL-KPN strains could be narrowed into fewer strains. Colonization of ESBL-KPN could be reversed upon return to the community.

Clinical Characteristics and Epidemiologic Study of Infection Due to Extended Spectrum beta-Lactamase Producing Organism in a Neonatal Intensive Care Unit / 소아과

PURPOSE: The extended-spectrum beta-lactamase(ESBL) producing organism have emerged to be an important pathogen in neonatal intensive care unit(NICU). This study was conducted to investigate incidence, characteristics and risk factors associated with ESBL organism among newborns in NICU. METHODS: The subjects included 98 newborns admitted to NICU at Asan Medical Center between September 1998 to July 2002, from whom a total of 177 ESBL organisms were detected. Annual number of isolates, distribution of cultured sites, types of illness and patient profile were retrospectively reviewed and risk factors associated with the infection were identified between control group of 115 non-infected newborns. RESULTS: Of 177 ESBL isolates, 150(84.7%) and 27(15.3%) were ESBL producing K. pneumoniae and E. coli, respectively. The annual number of isolates were 2(1.1%), 23(13.0%), 126(71.2%), 17(9.6%) and 9(5.1%) for years 1998 to 2002. The annual incidence of sepsis due to ESBL organism was 2.9%, 8.2%, 17.8%, 3.1% and 2.8% for years 1998 to 2002:Year 2000 being an outbreak. The ESBL organisms were largely found in bronchial aspirates and urine. The infected patients were younger gestational age. The mean cultivation period was at 29.1+/-2.8 days. The risk factors for infection included, in the order of frequency, total parenteral nutrition, central venous catheterization, ventilator care, respiratory distress syndrome and dexamethasone therapy. CONCLUSION: Awareness of increasing infection due to ESBL producing organism in NICU is important not only for infection control but also placing a great limit in use of antibiotics, especially in premature infants.

Maternal and Neonatal Outcome of Twin Pregnancies after in vitro Fertilization and Embryo Transfer

PURPOSE: To examine various neonatal outcomes and perinatal factors resulting from assisted reproduction compared to that of spontaneous conception. METHODS: This is a retrospective study. The control cases were all twins of spontaneous conception born between periods from January 1995 to June 2000. The study cases were identified from twins conceived by assisted reproduction in the same time peried. A total of 460 sets of twins consisted of 250 twins of spontaneous conception and 156 twins of assisted reproduction were studied. The primary outcomes were neonatal morbidity and mortality and the secondary outcomes were perinatal factors including number, length and cost of hospitalization for the delivery. RESULTS: No differences were seen in various neontal factors including gestational age, birth weight and incidences of respiratory distress syndrome, patent ductus arteriosus, necrotizing enterocolitis, hyperbilirubinemia, sepsis, intraventricular hemorrhage and the length of hospitalizations. Lower one minute and five minute Apgar scores and frequently encountered electrolyte abnormalities were observed in neonates of assisted reproduction. In general, the second twin of assisted reproduction had increased incidences of respiratory distress syndrome, sepsis and necrotizing enterocolitis than the first twin. Increased frequencies of preterm labor, hospitalization and elective cesarean section were seen among mothers who underwent artifical conception. However, overall hospital costs in terms of mothers hospitalization for the delivery and neonates hospitalization did not show differences. CONCLUSION: Assisted reproduction twins had similar neonatal morbidities, mortalities and perinatal morbidities compared to those born by spontaneous conception.

Comparison of Treatment Outcomes in Persistent Pulmonary Hypertension of the Newborn

PURPOSE: To compare the efficacy of conventional strategy versus high-frequency oscillatory ventilation (HFOV) and inhaled nitric oxide (iNO) for the treatment of full term neonates with persistent pulmonary hypertension (PPHN). METHODS: Full term infants admitted with diagnosis of PPHN to neonatal intensive care units of Asan Medical Center from a period of 1994 to 2001 were included. The major exclusion criteria included congenital anomalies and pulmonary hypoplasia caused by various etiologies. Demographic, therapeutic responses and outcomes were compared between two study phases depending upon treatment modalities used: phase 1 (January 1994-July 1997) using conventional strategy and phase II (July 1997-December 2001) using either conventional strategy or/with iNO or HFOV with iNO. RESULTS: A total of 16 patients and 32 patients were enrolled in phase I and phase II studies, respectively. The primary diagnosis for PPHN included idiopathic (n=12), hyaline membrane disease (n=16), meconium aspiration syndrome (n=11), and sepsis (n=10). Statistically significant improvements were noted in survival, oxygenation index and alveolar- arterial oxygen tension difference during phase II than phase I study period. 75% of those infants treated with iNO showed good responses. Improvements in duration of ventilator use, oxygen supplementation, hospitalization were noted during phase II study period, however, not statistically significant compared to phase I study period. The impairments in neurodevelopmental outcomes were noted in 1 and 2 patients during phase I and phase II study periods, respectively. CONCLUSION: We conclude that HFOV and iNO are more efficacious and safe rescue mode of treatment than conventional strategy for full term infants with PPHN.

Guideline in the Management of Antenatally Diagnosed Unilateral Hydronephrosis

PURPOSE: Neonatal hydronephrosis has been detected with increasing frequency with the widespread use of prenatal ultrasonography, but the consensus about its postnatal management has not yet been reached, especially about surgical intervention. We attempted to determine the guideline of follow-up study and surgical intervention of hydronephrosis by analyzing clinical outcomes of neonates with hydronephrosis. MATERIALS AND METHODS: Between 1994 and 2000, 128 hydronephrotic kidneys were postnatally confirmed. Cases associated with other urologic anomalies were excluded and 90 unilateral hydronephrotic kidneys with a minimum follow-up of 12 months were enrolled in this study. We classified the patients into 6 groups according to the anterior posterior pelvic diameter(APPD) at initial ultrasonography(USG) within 1 month after birth. Renal USG and Tc99m-mercaptoacetyl triglycerine(MAG3) scan were done according to a set protocol, and pyeloplasty was performed when indicated according to our protocol. RESULTS: Most cases whose APPD were below 10 mm improved or resolved. Only few cases with APPD above 20 mm showed spontaneous improvement and most(88%) had undergone operation. Those with initial APPD within 10-19 mm showed variable outcomes. When the risk factors for irreversible renal functional deterioration were analyzed, the age at pyeloplasty and pre-operative functional deficit were significant. CONCLUSION: We concluded that in infants with initial APPD below 10 mm, consideration of surgery is not needed, and in those with initial APPD above 20 mm, early operation is recommended. Our set protocol based on initial USG is useful, but the cut-off value of relative renal function(RRF) for operation might be increased to 40% to improve post operative RRF.

Longitudinal Growth of Hospitalized Very Low Birth Weight Infants

PURPOSE: This study was performed to investigate the postnatal growth for very low birth weight infants (VLBWI) and to evaluate the factors associated with growth during initial hospitalization. METHODS: The subjects for the study included 155 infants, birth weight less than 1, 625 g, who were admitted to neonatal intensive care unit of Asan Medical Center from January of 1999 to May of 2002. Infants with twin or triplet, necrotizing enterocolitis, small for gestational age and congenital abnormality were excluded. Nutrient intakes and body weights were recorded daily during the first 8 days, 11th and 14th day and then weekly after the 14th day. Length and head circumference were measured weekly. All of the data was collected up to postnatal 105 days or hospital discharge. Enteral plus parenteral fluid, calory, and protein intake were evaluated daily. RESULTS: Growth curves were made according to four birth weight groups: group of 750 g (625-874 g), 1, 000 g (875-1, 124 g), 1, 250 g (1, 125-1, 374 g), 1, 500 g (1, 375-1, 624 g), respectively. Mean fluid intake was 143.7 +/- 24.9 mL/kg/d, caloric intake was 78.1 +/- 10.5 kcal/kg/d and protein intake was 2.4 +/- 0.3 g/kg/d. The mean period to regain birth weight was 19.9 +/- 7.8 days and 25.4 +/-11.0, 22.2 +/- 7.5, 18.8+/- 7.3, 17.3 +/- 6.2 days were required, to regain birth weight for previously mentioned birth weight groups, respectively. Birth weight, gestational age, duration of total parenteral nutrition, age at starting of enteral feeding were negatively associated with the mean duration to regain birth weight. Duration of respiratory support and supplemental oxygen were negative predictors, unlike protein intake which revealed to be a positive predictor. CONCLUSION: Postnatal growth curves of VLBW infants were based on body weight, length, head circumference. Birth weight, gestational age, duration of total parenteral fluid, age at starting of enteral feeding were negatively associated with the mean duration to regain birth weight. There was a positive correlation with protein intake. More rapid regain to birth weight was associated with a shorter duration of respiratory support and supplemental oxygen.

Recent Outcome of Extremely Low Birth Weight Infants at Asan Medical Center

PURPOSE: Survival rate of infants weighing less than 1, 000 g has been increased due to advanced neonatal care. We evaluated the outcome of extremely low birth weight (ELBW) infants who were born at Asan Medical Center. METHODS: We retrospectively reviewed survival, morbidities, and catch-up growth of the 105 ELBW infants from 1999 to 2002. RESULTS: Overall survival rate of ELBW infants was 65.7%. In respect to birth weight, the survival rates for or = grade III, periventricular leukomalacia, severe retinopathy of prematurity > or = stage III and clinical or proven sepsis were 8.7%, 4.3%, 47.8%(n=33), 69.6%, respectively. 29 infants required laser photocoagulation due to retinopathy of prematurity. Duration of total parenteral nutrition (TPN) was 44.0 +/- 22.3 days. The incidences of TPN-associated cholestasis and necrotizing enterocolitis were 34.8%, 7.2%, repectively. At 18 months, 78.3% of ELBW infants showed catch-up growth. CONCLUSION: Survival rate of ELBW infants was 65.7%, which was much improved but lower than that of western and Japanese outcome. Further efforts must be made to increase their survival rates and to reduce morbidities.

Evaluation of i-STAT(TM) Portable Clinical Analyzer in a Neonatal Intensive Care Units / 대한주산의학회잡지

OBJECTIVES: OCT(Point-of-Care Test), often translated as "Bedside laboratory", is a testing method used in most developed countries to conduct medical research. It is known to extract rapid results that can be applied in the intensive care unit. This study was conducted to investigate the correlation of the i-STAT(TM) POCT analyzer with the traditional test in the neonatal intensive care units. METHODS: 60 babies(birth weight > or =1.0kg) who were admitted to neonatal intensive care unit from June, 2000 to June, 2001 at Asan Medical Center requiring blood samples for the testing of arterial blood gas analysis(ABGA), electrolytes, hemoglobin(Hb), hematocrit(Hct), were included in the study. Blood samples were taken simultaneously to be tested by the traditional laboratory method and by i-STAT(TM) (i-STAT Co. USA) POCT analyzer. The data used for comparison analyzation included pH, pCO2, pO2, HCO3, Na, K, Hb, and Hct. RESULTS: 245 measurements of ABGA and 195 measurements of Na, K, Hb, Hct from 60 babies were used for comparison. Good correlation of data was found between i-STAT(TM) POCT analyzer and traditional laboratory method obtained from the central laboratory(correlation coefficient: pH 0.954, pCO2 0.944, pO2 0.941, HCO3 0.880, Na 0.713, K 0.860, Hb 0.864, Hct 0.880). CONCLUSION: This study showed that i-STAT(TM) POCT analyzer provided accurate analytic results when compared with traditional laboratory method used in the neonatal intensive care units.

Postnatal Catch-up Growth of Very Low Birth Weight Infants

PURPOSE: The study was performed to examine postnatal growth curve for very low birth weight (VLBW) infants and to compare their catch-up growth in percentile with normal birth weight (NBW) infants. Also the role of various maternal and infant's factors that may predispose the VLBW infants for catch-up growth were evaluated. METHODS: The subjects for the study included 192 VLBW infants admitted to Asan Medical Center from January of 1997 to December of 1999. Of those 192 infants, a total of 113 infants were followed as an outpatient and their growth parameters including height, weight were obtained at each visit up to 18 months. We defined the catch-up growth as those who met 3rd percentile of normal Korean full term infant's growth curve. RESULTS: The results of the study showed that 3rd percentile mean body weight was attained by 18 months and 6 months in VLBW of less than 1,000 g and 1,000-1,499 g, respectively. The 3rd percentile mean height was attained by 18 months and 12 months for VLBW of less than 1,000 g and 1,000-1,499 g, respectively. Those infants of 1,000- 1,499 g attained 10th percentile weight and height by 15 months. The evaluation of the catch-up growth above 3rd percentile at various ages in month showed that weight attained above 3rd percentile were 42.5%, 73.5%, 80.5%, 87.6% and height attained above 3rd percentile were 33.6%, 75.2%, 89.4%, 92% at 6, 12, 15, 18 months, respectively. The result of logistic regression analysis of risk factors for catch-up growth at 12 months in VLBW infants revealed that gestational age and birth weight were important contributing factors. CONCLUSION: The 3rd percentile mean body weight and height were attained by 12 months in VLBW infants. Predisposing neonatal factors for catch-up growth included gestational age, birth weight, days of hospitalization, bronchopulmonary dysplasia (BPD), days of total parenteral nutrition and days of rehospitalization within 2 years after discharge from neonatal intensive care unit.

Delayed Intraventricular Hemorrhage in Premature Infants

PURPOSE: To determine incidence, characteristics and risk factors associated with delayed intraventricular hemorrage (IVH) in infants under 34 weeks old. METHODS: The medical records of infants with IVH admitted to neonatal intensive care unit of Asan Medical Center from January 1999 to December 2001 were reviewed retrospectively. Infants whose IVH was detected within 7 days of life and after 21 days of life were defined as "early hemorrahge group" and "delayed hemorrhage group", respectively. Various antenatal and neonatal factors were compared between these groups and risk factors leading to delayed IVH were identified. RESULTS: The incidence of delayed IVH was 28/103 (27.2%). The mean gestational age in delayed hemorrhage was 29.2+/-2.8 weeks. Lower birth weight, higher use of postnatal dexamethasone, antenatal dexamethasone and umbilical venous lines were noted in delayed hemorrhage group. Laboratory values associated with delayed IVH included lower platelet counts and hematocrit. Risk factors associated with delayed IVH included low hematocrit and elevated uric acid. Severe IVH (grade III, IV) occurred more in early hemorrhage group and subsequent 12 months follow-up showed developmental delay in 3 (4.0%) and 1 (3.6%) in early and delayed hemorrhage group, respectively. CONCLUSION: Frequent delayed hemorrhage may occur in infants under 34 weeks old. Although degree of delayed IVH is relatively milder than early hemorrhage group, its association with developmental delay merits follow-up head ultrasonogram up to at least 1 month of age or even longer.

Delayed Intraventricular Hemorrhage in Premature Infants

PURPOSE: To determine incidence, characteristics and risk factors associated with delayed intraventricular hemorrage (IVH) in infants under 34 weeks old. METHODS: The medical records of infants with IVH admitted to neonatal intensive care unit of Asan Medical Center from January 1999 to December 2001 were reviewed retrospectively. Infants whose IVH was detected within 7 days of life and after 21 days of life were defined as "early hemorrahge group" and "delayed hemorrhage group", respectively. Various antenatal and neonatal factors were compared between these groups and risk factors leading to delayed IVH were identified. RESULTS: The incidence of delayed IVH was 28/103 (27.2%). The mean gestational age in delayed hemorrhage was 29.2+/-2.8 weeks. Lower birth weight, higher use of postnatal dexamethasone, antenatal dexamethasone and umbilical venous lines were noted in delayed hemorrhage group. Laboratory values associated with delayed IVH included lower platelet counts and hematocrit. Risk factors associated with delayed IVH included low hematocrit and elevated uric acid. Severe IVH (grade III, IV) occurred more in early hemorrhage group and subsequent 12 months follow-up showed developmental delay in 3 (4.0%) and 1 (3.6%) in early and delayed hemorrhage group, respectively. CONCLUSION: Frequent delayed hemorrhage may occur in infants under 34 weeks old. Although degree of delayed IVH is relatively milder than early hemorrhage group, its association with developmental delay merits follow-up head ultrasonogram up to at least 1 month of age or even longer.

A Case of Autoimmune Enteropathy Treated with Corticosteroid and FK506 / 대한소아소화기영양학회지

Autoimmune enteropathy is a rare chronic diarrheal disease of infancy. Clinicopathologically, this entity is characterized by chronic secretory diarrhea, villous atrophy with crypt hypoplasia of a small intestine and/or associated autoimmune disorders, and absence of severe immunodeficiency. For the confirmation of diagnosis, antienterocyte autoantibody should be delineated. The treatment of choice of this disorder is immunosuppression. We has been experienced a case of autoimmune enteropathy without autoimmune disorders in a 10-month-old male infant. He developed protracted diarrhea from 5 months of his age and has been appeared to be failure to thrive. Antienterocyte autoantibody was demonstrated by immunohistochemistry and western blotting. He was successfully treated with corticosteroid and FK506. This is the first case report of autoimmune enteropathy without autoimmune disorders in Korea.