ABSTRACT
Importance: Inguinal hernia repair in preterm infants is common and is associated with considerable morbidity. Whether the inguinal hernia should be repaired prior to or after discharge from the neonatal intensive care unit is controversial. Objective: To evaluate the safety of early vs late surgical repair for preterm infants with an inguinal hernia. Design, Setting, and Participants: A multicenter randomized clinical trial including preterm infants with inguinal hernia diagnosed during initial hospitalization was conducted between September 2013 and April 2021 at 39 US hospitals. Follow-up was completed on January 3, 2023. Interventions: In the early repair strategy, infants underwent inguinal hernia repair before neonatal intensive care unit discharge. In the late repair strategy, hernia repair was planned after discharge from the neonatal intensive care unit and when the infants were older than 55 weeks' postmenstrual age. Main Outcomes and Measures: The primary outcome was occurrence of any prespecified serious adverse event during the 10-month observation period (determined by a blinded adjudication committee). The secondary outcomes included the total number of days in the hospital during the 10-month observation period. Results: Among the 338 randomized infants (172 in the early repair group and 166 in the late repair group), 320 underwent operative repair (86% were male; 2% were Asian, 30% were Black, 16% were Hispanic, 59% were White, and race and ethnicity were unknown in 9% and 4%, respectively; the mean gestational age at birth was 26.6 weeks [SD, 2.8 weeks]; the mean postnatal age at enrollment was 12 weeks [SD, 5 weeks]). Among 308 infants (91%) with complete data (159 in the early repair group and 149 in the late repair group), 44 (28%) in the early repair group vs 27 (18%) in the late repair group had at least 1 serious adverse event (risk difference, -7.9% [95% credible interval, -16.9% to 0%]; 97% bayesian posterior probability of benefit with late repair). The median number of days in the hospital during the 10-month observation period was 19.0 days (IQR, 9.8 to 35.0 days) in the early repair group vs 16.0 days (IQR, 7.0 to 38.0 days) in the late repair group (82% posterior probability of benefit with late repair). In the prespecified subgroup analyses, the probability that late repair reduced the number of infants with at least 1 serious adverse event was higher in infants with a gestational age younger than 28 weeks and in those with bronchopulmonary dysplasia (99% probability of benefit in each subgroup). Conclusions and Relevance: Among preterm infants with inguinal hernia, the late repair strategy resulted in fewer infants having at least 1 serious adverse event. These findings support delaying inguinal hernia repair until after initial discharge from the neonatal intensive care unit. Trial Registration: ClinicalTrials.gov Identifier: NCT01678638.
Subject(s)
Hernia, Inguinal , Herniorrhaphy , Infant, Premature , Female , Humans , Infant , Infant, Newborn , Male , Asian/statistics & numerical data , Bayes Theorem , Gestational Age , Hernia, Inguinal/epidemiology , Hernia, Inguinal/ethnology , Hernia, Inguinal/surgery , Herniorrhaphy/adverse effects , Herniorrhaphy/methods , Herniorrhaphy/statistics & numerical data , Patient Discharge , Age Factors , Hispanic or Latino/statistics & numerical data , White/statistics & numerical data , United States/epidemiology , Black or African American/statistics & numerical dataABSTRACT
OBJECTIVE: To determine the effects of late surfactant on respiratory outcomes determined at 1-year corrected age in the Trial of Late Surfactant (TOLSURF), which randomized newborns of extremely low gestational age (≤28 weeks' gestational age) ventilated at 7-14 days to late surfactant and inhaled nitric oxide vs inhaled nitric oxide-alone (control). STUDY DESIGN: Caregivers were surveyed in a double-blinded manner at 3, 6, 9, and 12 months' corrected age to collect information on respiratory resource use (infant medication use, home support, and hospitalization). Infants were classified for composite outcomes of pulmonary morbidity (no PM, determined in infants with no reported respiratory resource use) and persistent PM (determined in infants with any resource use in ≥3 surveys). RESULTS: Infants (n = 450, late surfactant n = 217, control n = 233) were 25.3 ± 1.2 weeks' gestation and 713 ± 164 g at birth. In the late surfactant group, fewer infants received home respiratory support than in the control group (35.8% vs 52.9%, relative benefit [RB] 1.28 [95% CI 1.07-1.55]). There was no benefit of late surfactant for No PM vs PM (RB 1.27; 95% CI 0.89-1.81) or no persistent PM vs persistent PM (RB 1.01; 95% CI 0.87-1.17). After adjustment for imbalances in baseline characteristics, relative benefit of late surfactant treatment increased: RB 1.40 (95% CI 0.89-1.80) for no PM and RB 1.24 (95% CI 1.08-1.42) for no persistent PM. CONCLUSION: Treatment of newborns of extremely low gestational age with late surfactant in combination with inhaled nitric oxide decreased use of home respiratory support and may decrease persistent pulmonary morbidity. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01022580.
Subject(s)
Infant, Extremely Low Birth Weight , Nitric Oxide/administration & dosage , Pulmonary Surfactants/administration & dosage , Respiration, Artificial/methods , Respiratory Distress Syndrome, Newborn/therapy , Administration, Inhalation , Age Factors , Bronchopulmonary Dysplasia/prevention & control , Confidence Intervals , Dose-Response Relationship, Drug , Double-Blind Method , Drug Administration Schedule , Female , Follow-Up Studies , Gestational Age , Humans , Infant , Infant, Newborn , Male , Respiratory Distress Syndrome, Newborn/diagnosis , Risk Assessment , Survival Rate , Time FactorsABSTRACT
Progress has been made in the reduction of morbidity and mortality from neonatal sepsis. However, diagnosis continues to rely primarily on conventional microbiologic techniques, which can be inaccurate. The objective of this review is to provide the clinician with an overview of the current information available on diagnosing this condition. We review currently available diagnostic approaches for documenting neonatal sepsis and also describe novel approaches for diagnosing infection in neonates who are under development and investigation. Substantial progress has been made with molecular approaches and further development of non-culture-based methods offer promise. The potential ability to incorporate antimicrobial resistance gene testing in addition to pathogen identification may provide a venue to incorporate a predominantly molecular platform into a larger program of neonatal care.
Subject(s)
Bacteriological Techniques , Biomarkers/blood , DNA, Bacterial/genetics , Gene Expression Profiling , Molecular Diagnostic Techniques , Neonatal Sepsis/diagnosis , Blood Cell Count , Genetic Markers , Humans , Infant, Newborn , Neonatal Sepsis/blood , Neonatal Sepsis/genetics , Neonatal Sepsis/microbiology , Predictive Value of Tests , Prognosis , Reproducibility of Results , Time FactorsABSTRACT
OBJECTIVE: To assess whether late surfactant treatment in extremely low gestational age (GA) newborn infants requiring ventilation at 7-14 days, who often have surfactant deficiency and dysfunction, safely improves survival without bronchopulmonary dysplasia (BPD). STUDY DESIGN: Extremely low GA newborn infants (GA ≤28 0/7 weeks) who required mechanical ventilation at 7-14 days were enrolled in a randomized, masked controlled trial at 25 US centers. All infants received inhaled nitric oxide and either surfactant (calfactant/Infasurf) or sham instillation every 1-3 days to a maximum of 5 doses while intubated. The primary outcome was survival at 36 weeks postmenstrual age (PMA) without BPD, as evaluated by physiological oxygen/flow reduction. RESULTS: A total of 511 infants were enrolled between January 2010 and September 2013. There were no differences between the treated and control groups in mean birth weight (701 ± 164 g), GA (25.2 ± 1.2 weeks), percentage born at GA <26 weeks (70.6%), race, sex, severity of lung disease at enrollment, or comorbidities of prematurity. Survival without BPD did not differ between the treated and control groups at 36 weeks PMA (31.3% vs 31.7%; relative benefit, 0.98; 95% CI, 0.75-1.28; P = .89) or 40 weeks PMA (58.7% vs 54.1%; relative benefit, 1.08; 95% CI, 0.92-1.27; P = .33). There were no between-group differences in serious adverse events, comorbidities of prematurity, or severity of lung disease to 36 weeks. CONCLUSION: Late treatment with up to 5 doses of surfactant in ventilated premature infants receiving inhaled nitric oxide was well tolerated, but did not improve survival without BPD at 36 or 40 weeks. Pulmonary and neurodevelopmental assessments are ongoing. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01022580.
Subject(s)
Bronchopulmonary Dysplasia/etiology , Nitric Oxide/administration & dosage , Pulmonary Surfactants/therapeutic use , Respiration, Artificial/adverse effects , Administration, Inhalation , Bronchopulmonary Dysplasia/epidemiology , Female , Humans , Infant, Newborn , Infant, Premature , Infant, Premature, Diseases/mortality , Infant, Premature, Diseases/therapy , Infant, Very Low Birth Weight , Male , Nitric Oxide/adverse effects , Pulmonary Surfactants/adverse effects , Respiration, Artificial/mortality , Survival Rate , United StatesABSTRACT
IMPORTANCE: Invasive candidiasis in premature infants causes death and neurodevelopmental impairment. Fluconazole prophylaxis reduces candidiasis, but its effect on mortality and the safety of fluconazole are unknown. OBJECTIVE: To evaluate the efficacy and safety of fluconazole in preventing death or invasive candidiasis in extremely low-birth-weight infants. DESIGN, SETTING, AND PATIENTS: This study was a randomized, blinded, placebo-controlled trial of fluconazole in premature infants. Infants weighing less than 750 g at birth (N = 361) from 32 neonatal intensive care units (NICUs) in the United States were randomly assigned to receive either fluconazole or placebo twice weekly for 42 days. Surviving infants were evaluated at 18 to 22 months corrected age for neurodevelopmental outcomes. The study was conducted between November 2008 and February 2013. INTERVENTIONS: Fluconazole (6 mg/kg of body weight) or placebo. MAIN OUTCOMES AND MEASURES: The primary end point was a composite of death or definite or probable invasive candidiasis prior to study day 49 (1 week after completion of study drug). Secondary and safety outcomes included invasive candidiasis, liver function, bacterial infection, length of stay, intracranial hemorrhage, periventricular leukomalacia, chronic lung disease, patent ductus arteriosus requiring surgery, retinopathy of prematurity requiring surgery, necrotizing enterocolitis, spontaneous intestinal perforation, and neurodevelopmental outcomes-defined as a Bayley-III cognition composite score of less than 70, blindness, deafness, or cerebral palsy at 18 to 22 months corrected age. RESULTS: Among infants receiving fluconazole, the composite primary end point of death or invasive candidiasis was 16% (95% CI, 11%-22%) vs 21% in the placebo group (95% CI, 15%-28%; odds ratio, 0.73 [95% CI, 0.43-1.23]; P = .24; treatment difference, -5% [95% CI, -13% to 3%]). Invasive candidiasis occurred less frequently in the fluconazole group (3% [95% CI, 1%-6%]) vs the placebo group (9% [95% CI, 5%-14%]; P = .02; treatment difference, -6% [95% CI, -11% to -1%]). The cumulative incidences of other secondary outcomes were not statistically different between groups. Neurodevelopmental impairment did not differ between the groups (fluconazole, 31% [95% CI, 21%-41%] vs placebo, 27% [95% CI, 18%-37%]; P = .60; treatment difference, 4% [95% CI, -10% to 17%]). CONCLUSIONS AND RELEVANCE: Among infants with a birth weight of less than 750 g, 42 days of fluconazole prophylaxis compared with placebo did not result in a lower incidence of the composite of death or invasive candidiasis. These findings do not support the universal use of prophylactic fluconazole in extremely low-birth-weight infants. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00734539.
Subject(s)
Antifungal Agents/therapeutic use , Candidiasis, Invasive/prevention & control , Fluconazole/therapeutic use , Infant, Premature, Diseases/prevention & control , Female , Humans , Infant Mortality , Infant, Low Birth Weight , Infant, Newborn , Infant, Very Low Birth Weight , Intensive Care Units, Neonatal , Length of Stay , Male , Single-Blind MethodABSTRACT
OBJECTIVE: Neonatal hypoglycemia is a common diagnosis for which management strategies vary. Our goal was to implement hypoglycemia algorithms (HGA) to streamline management of neonatal hypoglycemia within our hospital system and improve outcomes related to promoting the mother-infant dyad and decreasing hospital costs. PATIENTS AND METHODS: A retrospective cohort study analyzed data on 4,666 asymptomatic infants at risk for hypoglycemia and born at two, large, community hospitals between 2010 and 2016. The first algorithm (HGA1) was created in 2012 and subsequently updated (HGA2) in 2014 to include the use of dextrose gel. Infants were separated into three groups by epoch: pre-HGA (2010-2011), HGA1 (2012-2013), and HGA2 (2014-2016). Outcomes between groups were then analyzed. Cost savings were calculated using linear regression. RESULTS: Compared with the pre-HGA group, the HGA1 group had decreased intravenous dextrose use (3.9 vs. 2.5%, p < .001). Compared with the HGA1 group, the HGA2 group had decreased intravenous dextrose use (2.5 vs. 1.0%, p < .001) and increased breastfeeding rates (88.4% vs. 86.7%, p = .003). Neonatal intensive care unit admission rates decreased when comparing the pre-HGA group with the HGA2 group (10.6% vs 9.4%, p = .03). Length of stay was overall unchanged. Total cost savings were approximately $222 per case. CONCLUSIONS: By implementing HGA1 and providing resources to unify care for asymptomatic infants at risk for hypoglycemia, short-term outcomes in our hospital system improved. By updating HGA2 to include the use of dextrose gel, the advantages gained by HGA1 were maintained and further enhanced. Overall cost of care was reduced.
Subject(s)
Fetal Diseases , Hypoglycemia , Infant, Newborn, Diseases , Algorithms , Female , Gels , Glucose , Hospitals , Humans , Hypoglycemia/diagnosis , Hypoglycemia/epidemiology , Hypoglycemia/therapy , Infant, Newborn , Infant, Newborn, Diseases/diagnosis , Infant, Newborn, Diseases/epidemiology , Infant, Newborn, Diseases/therapy , Retrospective Studies , Sweetening AgentsABSTRACT
Life-threatening gastrointestinal (GI) diseases of prematurity are highly associated with systemic candidiasis. This implicates the premature GI tract as an important site for invasion by Candida. Invasive interactions of Candida spp. with immature enterocytes have heretofore not been analyzed. Using a primary immature human enterocyte line, we compared the ability of multiple isolates of different Candida spp. to penetrate, injure, and induce a cytokine response from host cells. Of all the Candida spp. analyzed, C. albicans had the greatest ability to penetrate and injure immature enterocytes and to elicit IL-8 release (p < 0.01). In addition, C. albicans was the only Candida spp. to form filamentous hyphae when in contact with immature enterocytes. Similarly, a C. albicans mutant with defective hyphal morphogenesis and invasiveness had attenuated cytotoxicity for immature enterocytes (p < 0.003). Thus, hyphal morphogenesis correlates with immature enterocyte penetration, injury, and inflammatory responses. Furthermore, variability in enterocyte injury was observed among hyphal-producing C. albicans strains, suggesting that individual organism genotypes also influence host-pathogen interactions. Overall, the finding that Candida spp. differed in their interactions with immature enterocytes implicates that individual spp. may use different pathogenesis mechanisms.
Subject(s)
Candida/pathogenicity , Enterocytes/microbiology , Host-Pathogen Interactions , Bacterial Adhesion , Candida/classification , Candida/genetics , Cell Line , Enterocytes/immunology , Enterocytes/pathology , Genotype , Host-Pathogen Interactions/genetics , Humans , Hyphae , Inflammation Mediators/metabolism , Interleukin-8/metabolism , Mutation , PhenotypeABSTRACT
BACKGROUND: The incidence of systemic nonalbicans Candida (especially C. glabrata) infections is increasing dramatically in intensive care units, but relatively little is known about the pathogenesis or host defenses associated with these life threatening infections. MATERIALS AND METHODS: The course of systemic C. glabrata infection was assessed as the fungal burden in the kidneys and livers of mice sacrificed 1, 8, and 15 d after intravenous C. glabrata. Sixteen hours before each sacrifice, half of the mice were injected intraperitoneally with intact viable or nonviable E. coli cells, or with E. coli lipopolysaccharide (LPS), or with tumor necrosis factor (TNF)-alpha. To clarify the effect of LPS and TNF-alpha on phagocytosis, resident (unstimulated) mouse peritoneal macrophages were harvested, cultivated ex vivo, and some cultures were treated with LPS or TNF-alpha prior to 30 min incubation with C. glabrata. RESULTS: Compared with mice injected with vehicle, each agent (intact E. coli cells or E. coli LPS or TNF-alpha) was consistently associated with decreased numbers of tissue C. glabrata, and some of these decreases were significant (P < 0.05). Compared with untreated macrophages, phagocytosis of C. glabrata was increased with LPS-treated macrophages (P < 0.01), and phagocytosis was also increased in the presence of TNF-alpha (P < 0.01). CONCLUSION: E. coli LPS and TNF-alpha may participate in host defense against C. glabrata by a mechanism involving increased macrophage phagocytosis, suggesting that stimulation of inflammatory cytokines may facilitate host clearance of C. glabrata.
Subject(s)
Candida glabrata/physiology , Escherichia coli/physiology , Macrophages, Peritoneal/physiology , Phagocytosis/physiology , Tumor Necrosis Factor-alpha/physiology , Animals , Candidiasis/prevention & control , Cells, Cultured , Disease Models, Animal , Female , Kidney/microbiology , Lipopolysaccharides/pharmacology , Liver/microbiology , Macrophages, Peritoneal/cytology , MiceABSTRACT
Candida glabrata is the second or third most frequent cause of candidaemia. The gastrointestinal tract is considered to be a major portal of entry for systemic candidiasis, but relatively few studies have investigated the pathogenesis of C. glabrata. Experiments were designed to clarify the ability of C. glabrata to disseminate from the mouse intestinal tract. Following oral inoculation, C. glabrata readily colonized the caeca [approx. 10(7) cells (g caecum)(-1)] of antibiotic-treated mice, but extraintestinal dissemination was not detected. Superimposing several mouse models of trauma and/or immunosuppression known to induce dissemination of Candida albicans and other intestinal microbes did not cause C. glabrata to disseminate often, although one exception was mice given high doses of dexamethasone for 4 days. These data support the hypothesis that the antibiotic-treated mouse intestine may be an epidemiological reservoir for C. glabrata and that this yeast tends to disseminate under specific clinical conditions.
Subject(s)
Candida glabrata/growth & development , Candidiasis/microbiology , Cecum/microbiology , Animals , Anti-Bacterial Agents/pharmacology , Colony Count, Microbial , Dexamethasone/administration & dosage , Dexamethasone/pharmacology , Disease Models, Animal , Escherichia coli/growth & development , Female , Immunosuppression Therapy , Immunosuppressive Agents/administration & dosage , Immunosuppressive Agents/pharmacology , Kidney/microbiology , Liver/microbiology , Lymph Nodes/microbiology , Mice , Wounds and Injuries/complicationsABSTRACT
Candida albicans is a pleomorphic fungus with budding yeast and filamentous forms, and is a frequent cause of complicating infections in patients who are postsurgical, in shock, and have trauma. Many cases of systemic candidiasis are thought to orginate from the intestine, but it is unclear if the filament or the yeast is the more invasive form. Because C. albicans is relatively noninvasive and because mesenteric ischemia is thought to facilitate extraintestinal microbial dissemination, wild-type C. albicans CAF2 and mutant HLC54 (defective in filament formation) were orally inoculated into antibiotic-treated mice that were housed exclusively in room air, or were intermittently exposed to 10% oxygen for 1-h intervals. Both strains of C. albicans colonized the cecum in similar numbers (approximately 10(6.7)/g). C. albicans translocation to the draining mesenteric lymph nodes was not detected in mice inoculated with CAF2 (normoxic or hypoxic) or in normoxic mice inoculated with HLC54, but was detected in 33% (P < 0.01) of hypoxic mice inoculated with HLC54. Using Caco-2 and HT-29 enterocytes cultivated on plastic dishes and pretreated for 48 h in 10% oxygen, adherence of C. albicans HLC54 was decreased compared with wild-type CAF2, and hypoxia had no noticeable effect on adherence of either CAF2 or HLC54. Using enterocytes cultivated on permeable 8-microm filters, transepithelial migration of C. albicans CAF2 and HLC54 appeared similar. Thus, C. albicans HLC54 (defective in filament formation) was more invasive in hypoxic mice compared with wild-type CAF2, and host factors (e.g., mesenteric ischemia) rather than an innate ability to interact with enterocytes might play a more important role in extraintestinal dissemination of C. albicans yeast forms.
Subject(s)
Candidiasis/physiopathology , Cecal Diseases/microbiology , Cell Hypoxia/physiology , Intestinal Diseases/microbiology , Animals , Candida albicans/classification , Cell Adhesion , Female , Humans , Intestinal Diseases/physiopathology , Mice , Tumor Cells, CulturedABSTRACT
Candida species are important nosocomial pathogens in the newborn population, particularly among the premature very-low-birth-weight infants in neonatal intensive care units. Candida colonization of the neonatal skin and gastrointestinal tract is an important first step in the pathogenesis of invasive disease. C albicans is the most commonly isolated species in colonized or infected infants. Over the past decade the incidence of both colonization and infection with other Candida species, particularly C parapsilosis, has risen dramatically. Colonization of the infant occurs early in life and is affected by a variety of common practices in neonatal intensive care. Microbial factors also augment colonization, including the ability of Candida to adhere to human epithelium. A better understanding of the complex interactions between host risk factors and virulence traits of colonizing yeast may allow the risk of systemic spread to be reduced in the population of premature infants.
Subject(s)
Candida/pathogenicity , Candidiasis/microbiology , Cross Infection/microbiology , Fungemia/microbiology , Bacterial Adhesion , Candida/physiology , Colony Count, Microbial , Epithelium , Humans , Infant, Newborn , Infant, Premature , Infant, Very Low Birth Weight , Intensive Care Units, NeonatalABSTRACT
Human cytomegalovirus (CMV) infection may be acquired in very low birth weight and extremely low birth weight (ELBW) infants from breast milk. The clinical relevance of such infections is uncertain. There is no consensus on whether screening breast milk for CMV, freezing/pasteurizing milk before feeding, or performing virological monitoring on at-risk infants is warranted. We describe an ELBW infant who acquired CMV postnatally from breast milk and developed CMV sepsis syndrome and clinical evidence of necrotizing enterocolitis (NEC) at ≈ 5 weeks of age. The availability of serial dried blood spots from day of life (DOL) 4 to 21, coincidentally obtained for a metabolic study, provided the novel opportunity to retrospectively test for and quantify the magnitude of CMV DNAemia. DNAemia was present for several weeks before the onset of severe CMV disease, first being noted on DOL 18 and increasing in magnitude daily to 4.8 log10 genomes/mL on DOL 21, approximately 8 days before the onset of abdominal distension and 15 days before the onset of CMV sepsis syndrome and NEC. After surgical resection, supportive care, and ganciclovir therapy, the infant recovered. This case underscores the importance of including CMV infection in the differential diagnosis of sepsis and NEC in premature infants. This case also suggests the value of prospective virological monitoring in at-risk low birth weight and ELBW infants. Future studies should examine the potential utility of preemptive monitoring for, and possibly treatment of, CMV DNAemia in premature infants, which may herald the onset of serious disease.
Subject(s)
Asymptomatic Diseases , Cytomegalovirus , DNA, Viral , Enterocolitis, Necrotizing/diagnosis , Infant, Premature , Cytomegalovirus/isolation & purification , Enterocolitis, Necrotizing/virology , Humans , Infant, Newborn , MaleABSTRACT
Candida parapsilosis (CP) (n = 40) isolated from an unselected patient population in the neonatal intensive care units (NICUs) of three US hospitals were collected over periods of 3.5-9 years. Two previously published microsatellite markers and three additional trinucleotide markers were used to produce multiplex genotypes, which revealed broad strain diversity among the NICU isolates with a combined index of discrimination (D) = 0.997. A cluster of eight related CP strains from four infants in a single NICU was observed. An extended collection of 24 CP isolates from the general population of that hospital showed that the cluster of NICU isolates was related to three isolates from general hospital patients. This microsatellite marker set is suitable to investigate clusters of colonizing and infecting strains of CP.
Subject(s)
Candida/genetics , Candidiasis/microbiology , Cross Infection/microbiology , Intensive Care Units, Neonatal , Microsatellite Repeats , Candida/classification , Cluster Analysis , Cohort Studies , Genetic Markers/genetics , Genetic Variation , Genotype , Humans , Infant, Newborn , Molecular Epidemiology , PhylogenySubject(s)
Candidiasis/epidemiology , Cross Infection/epidemiology , Fungemia/epidemiology , Infant, Premature , Amphotericin B/therapeutic use , Candidiasis/diagnosis , Candidiasis/drug therapy , Cross Infection/diagnosis , Cross Infection/drug therapy , Female , Fungemia/diagnosis , Fungemia/drug therapy , Humans , Incidence , Infant, Newborn , Infant, Very Low Birth Weight , Intensive Care Units, Neonatal , Male , Risk Assessment , Survival Rate , United States/epidemiologyABSTRACT
Infections with Candida albicans have become a significant problem among very low birth weight infants in the neonatal intensive care unit. Risk factors are multiple and include administration of antibiotics and glucocorticoids, such as dexamethasone. Experiments were designed to study the combined effect of oral broad-spectrum antibiotics and parenteral dexamethasone on cecal colonization and extraintestinal dissemination of C. albicans in separate groups of mice that were orally inoculated with one of four C. albicans strains that were either wild-type INT1/INT1 or had one or more disruptions of the INT1 gene. Intestinal colonization was monitored by quantitative culture of the mouse cecum, and extraintestinal invasion was monitored by quantitative culture of the draining mesenteric lymph nodes and kidneys. At sacrifice, the average numbers of cecal C. albicans differed from 7.7 log(10)/g to 6.7 log(10)/g (p < 0.01) in mice orally inoculated with C. albicans containing two functional copies of INT1 and no functional copies of INT1, respectively. The incidence of extraintestinal dissemination to mesenteric lymph nodes and kidneys correspondingly varied from 57 to 13% (p < 0.01) and 83 to 4% (p < 0.01) in mice inoculated with these two C. albicans strains. Mice orally inoculated with C. albicans containing one functional copy of INT1 had intermediate levels of cecal colonization and extraintestinal dissemination. Thus, cecal colonization and extraintestinal dissemination of C. albicans was facilitated in antibiotic-treated mice given dexamethasone. In addition, the presence of two functional copies of the INT1 gene was associated with the greatest levels of cecal colonization and extraintestinal dissemination of C. albicans.
Subject(s)
Anti-Bacterial Agents/pharmacology , Candida albicans/pathogenicity , Candidiasis/mortality , Cecum/microbiology , Dexamethasone/pharmacology , Glucocorticoids/pharmacology , Animals , Candida albicans/isolation & purification , Female , Kidney/microbiology , Mesenteric Lymphadenitis/mortality , Mice , VirulenceABSTRACT
OBJECTIVE: Systemic candidiasis is a major cause of complicating infections in intensive care units. Morbidity and mortality are high, even in those who receive appropriate antifungal therapy. Because the intestinal tract is considered a major portal of entry for systemic candidiasis, experiments were designed to clarify the ability of yeast and filamentous forms, as well as the INT1 gene product, to influence adherence of Candida albicans to the intestinal epithelium. DESIGN: Controlled. SETTING: University teaching hospital research laboratory. SUBJECTS: Mature Caco-2 and HT-29 cultured enterocytes. INTERVENTIONS: C. albicans INT1 mutant strains, defective in filament production, were used to observe the ultrastructural surface interactions of C. albicans with cultured intestinal epithelial cells, namely Caco-2 and HT-29 cells. These mutant strains also were used to quantify the effect of the INT1 gene product on C. albicans adherence (yeast and filamentous forms) to cultured enterocytes. Ultrastructural surface interactions of C. albicans with cultured enterocytes were observed with high resolution scanning electron microscopy. C. albicans adherence to cultured enterocytes was quantified by using a colorimetric enzyme-linked immunosorbent assay. MEASUREMENTS AND MAIN RESULTS: Both yeast and filamentous forms of C. albicans appeared tightly adherent to the apical surface of cultured enterocytes, and INT1 appeared to have little, if any, effect on these ultrastructural surface interactions. The distal ends of C. albicans filaments appeared to mediate adherence to enterocyte apical microvilli, and thigmotropism (contact guidance) appeared to play a role in C. albicans adherence. The absence of functional INT1 was associated with decreased adherence of C. albicans yeast forms to cultured enterocytes. CONCLUSIONS: Although functional INT1 appeared to facilitate adherence of C. albicans yeast forms to cultured enterocytes, the role of INT1 in adherence of filamentous forms was unclear, and both yeast and filamentous forms could adhere to, and perhaps invade, the apical surface of cultured enterocytes.
Subject(s)
Caco-2 Cells/microbiology , Candida albicans/pathogenicity , Enterocytes/microbiology , Fungal Proteins , HT29 Cells/microbiology , Caco-2 Cells/ultrastructure , Candida albicans/ultrastructure , Cell Adhesion , Cell Adhesion Molecules/physiology , Enterocytes/ultrastructure , HT29 Cells/ultrastructure , Humans , In Vitro Techniques , Microscopy, Electron, ScanningABSTRACT
OBJECTIVE: Candida albicans, a dimorphic fungus that switches from yeast to filamentous forms, is a major cause of complicating systemic infection in intensive care patients. The aim of this study was to compare the pathogenic potential of C. albicans yeast and filamentous forms. DESIGN: Separate groups of mice were inoculated either intravenously or orally with C. albicans CAF2 (wild type), HLC54 (yeast forms defective in filament formation), or BCa2-10 (constitutively filamentous). Mice were killed 1, 7, 14, and 21 days after intravenous C. albicans and kidneys and liver were quantitatively cultured; cohort groups were observed for mortality. Mice were pretreated with antibiotics for 3 days before oral inoculation with C. albicans, and killed 3 days later with dexamethasone administered for the latter 3 days; at sacrifice, the mesenteric lymph nodes and kidneys were cultured to monitor extraintestinal dissemination of C. albicans. SETTING: University teaching hospital research laboratory. SUBJECTS: Female, Swiss Webster, adult mice. MEASUREMENTS AND MAIN RESULTS: In intravenously inoculated mice, mortality was highest with wild-type C. albicans CAF2 (92%), intermediate with HLC54 (56%), and not detected with constitutively filamentous BCa2-10 (0%); BCa2-10 was cleared from the kidney and liver, but CAF2 and HLC54 were recovered at approximately 10(5-7)/g kidney and 10(4-5)/g liver. There was only occasional mortality in orally inoculated mice and the numbers of cecal C. albicans CAF2 and HLC54 were similarly high (approximately 10(7)/g), whereas numbers of cecal BCa2-10 were at least 100-fold lower. Extraintestinal dissemination was greatest with HLC54, intermediate with CAF2, and undetectable with BCa2-10. CONCLUSIONS: Of the three C. albicans strains studied, wild-type CAF2 was most virulent in intravenously inoculated mice and HLC54 (defective in filament formation) was most virulent in orally inoculated mice. The constitutively filamentous BCa2-10 was avirulent in both models, suggesting that filamentous forms by themselves might not be critically important for C. albicans virulence.