Candida: an increasingly important pathogen in the nursery

Candida Bloodstream Infections: Changes in Epidemiology and Increase in Drug Resistance

The literature on bloodstream infections (BSIs) have predominantly been biased towards bacteria, given their superior clinical significance in comparison with the other types of microorganisms. Fungal pathogens have epidemiologically received relatively less attention, although they constitute an important proportion of BSI aetiologies. In this review, the authors discuss the clinical relevance of fungal BSIs in the context of Candida species, as well as treatment options for the infections, emphasizing the compelling need to develop newer antifungals and strengthen antimicrobial stewardship programmes in the wake of the rapid spread of antifungal resistance.

CNS Macrophages and Infant Infections

The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.

Intracardiac Fungal Mass in a Term Neonate

Systemic fungal infections pose insidious challenges in neonatal intensive care settings. We present the case of a 9-day-old male term neonate admitted for polymicrobial sepsis and hepatic dysfunction who later developed candidemia superinfection. Despite broad antifungal therapy, the fungemia was complicated by progressive growth of a fungus ball in the right ventricular outflow tract that threatened cardiac function. Surgical excision of the mass was undertaken by right atriotomy and histologic examination confirmed Candida albicans.

Invasive candidiasis and candidaemia in neonates and children: update on current guidelines

Invasive candidiasis (IC) and candidaemia are leading causes of infectious morbidity and mortality among immunocompromised paediatric patients and those admitted to intensive care units. Despite improvements in diagnosis, prevention and treatment, both mortality rates and the economic burden of disease still remain high. To address this issue, several international societies and organisations have proposed guidelines for the management of IC/candidaemia in both neonates and children. In this article, we review current recommendations of the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia, the European Society of Clinical Microbiology and Infectious Diseases and the German Speaking Mycological Society/Paul-Ehrlich Society for Chemotherapy for the management and prevention of IC/candidaemia in children and neonates.

Successful caspofungin treatment of persistent candidemia in extreme prematurity at 23 and 24 weeks' gestation

Systemic fungal infection continues to be a major cause of mortality in extremely low-birth-weight premature infants. Amphotericin B has been recommended as the primary treatment; however, its use is limited due to drug-induced nephrotoxicity and amphotericin B-resistant candidemia. Caspofungin therapy was initiated in seven extremely premature infants at 23 and 24 weeks' gestation with persistent systemic candidiasis despite liposomal amphotericin B treatment. The gestational age was 23(+1)-24(+6) weeks, and birth weight was 530-825 g. Of the seven patients, the peripheral blood cultures of six patients were positive for Candida parapsilosis and one had positive culture for Candida albicans. The dosage of caspofungin was 2 mg/kg/day, and the mean treatment duration was 14 days. All of the persistent candidemia resolved on caspofungin therapy. There was no recurrent candidemia after discontinuing caspofungin. There were no adverse effects, hepatotoxicity, nephrotoxicity, anemia, or thrombocytopenia. Caspofungin successfully treated persistent candidemia in extremely premature infants at 23 and 24 weeks' gestational age.

Epidemiology and changes in patient-related factors from 1997 to 2009 in clinical yeast isolates related to dermatology, gynaecology, and paediatrics

From 1997 to 2009, 1,862 dermatology, gynaecology, and paediatrics (DGP) associated clinical yeast isolates were analysed for species occurrence, specimen origin and type, (multi-) resistance pattern, and testing period. The top seven of the isolated DGP-associated species remained the same as compared to total medical wards, with Candida albicans (45%) as most frequent pathogen. However, the DGP wards and DGP ICUs showed species-specific profiles; that is, the species distribution is clinic-specific similar and however differs in their percentage from ward to ward. By applying the "one fungus one name" principle, respectively, the appropriate current taxonomic species denominations, it has been shown that no trend to emerging species from 1998 to 2008 could be detected. In particular the frequently isolated non-Candida albicans species isolated in the DGP departments have already been detected in or before 1997. As yeasts are part of the cutaneous microbiota and play an important role as opportunistic pathogens for superficial infections, proper identification of the isolates according to the new nomenclature deems to be essential for specific and calculated antifungal therapy for yeast-like DGP-related infectious agents.

Trends in epidemiology of neonatal sepsis in a tertiary center in Korea: a 26-year longitudinal analysis, 1980-2005

There were many reports of longitudinal changes in the causative organisms of neonatal sepsis in Western countries but few in Asia. We aimed to study longitudinal trends in the epidemiology of neonatal sepsis at Seoul National University Children's Hospital (SNUCH), a tertiary center in Korea, and compared the results to previous studies of Western countries. The medical records of all of the neonates who were hospitalized at SNUCH from 1996 to 2005 with positive blood cultures were reviewed. We also compared the findings to previous 16-yr (1980-1995). One hundred and forty-nine organisms were identified in 147 episodes from 134 infants. In comparison with the previous 16-yr studies, there was a decrease in the number of Escherichia coli infections (16.2% vs 8.7%: odds ratio [OR] 0.495; 95% confidence interval [CI], 0.255-0.962; P = 0.035), but an increase in Staphylococcus aureus (16.6% vs 25.5%: OR 1.720; 95% CI, 1.043-2.839; P = 0.033) and fungal infections (3.3% vs 18.7%: OR 6.740; 95% CI, 2.981-15.239; P < 0.001), predominantly caused by Candida species. In conclusion, the incidence of sepsis caused by E. coli decreases, but S. aureus and fungal sepsis increases significantly. Compared with Western studies, the incidence of sepsis caused by S. aureus and fungus has remarkably increased.

Oral candidosis and its role in immunocompromised patients

The increased incidence of invasive candidosis in numerous categories of patients, including neonates, cancer patients, AIDS patients and patients who have undergone organ transplantation, is of great concern for the physicians involved. The manifestations of candidosis are numerous, and various clinical entities such as localized and disseminated infection have to be considered separately. All types of localized candidosis per se are usually not the main cause of disseminated disease. However, spreading of the mycotic pathogens in the gastrointestinal tract could induce disseminated candidosis. Prophylactic measurements in risk patients and consequent local and, if necessary, systemic treatment is recommended in these clinical entities.

Fluconazole prophylaxis in extremely low birth weight neonates reduces invasive candidiasis mortality rates without emergence of fluconazole-resistant Candida species

OBJECTIVE

We evaluated the impact of fluconazole prophylaxis for extremely low birth weight infants on invasive candidiasis incidence, invasive candidiasis-related mortality rates, and fluconazole susceptibility of Candida isolates.

METHODS

Extremely low birth weight infants <5 days of age, except those with liver dysfunction, were eligible for fluconazole prophylaxis. NICU infants (all birth weights) with invasive candidiasis between April 2002 and March 2006 were compared with those with invasive candidiasis before fluconazole prophylaxis (2000-2001).

RESULTS

Twenty-two infants had invasive candidiasis (all candidemia) during fluconazole prophylaxis; before fluconazole prophylaxis, there were 19 cases (candidemia: 17 cases; meningitis: 2 cases). Invasive candidiasis incidence in NICU infants decreased from 0.6% (19 of 3012 infants) before fluconazole prophylaxis to 0.3% (22 of 6393 infants) in 2002-2006 and that in extremely low birth weight infants decreased 3.6-fold. No Candida-attributable deaths occurred during 2002-2006 fluconazole prophylaxis, compared with 4 (21%) before fluconazole prophylaxis. The onset of invasive candidiasis was later during 2002-2006 (23.5 vs 12 days), but risk factors were similar. The invasive candidiasis species distribution remained stable. Of 409 infants who received fluconazole prophylaxis, 119 (29%) received 42 days. Shorter fluconazole prophylaxis duration was related to intravenous access no longer being necessary in 242 cases (59%), noninvasive candidiasis-related death in 29 (7%), hospital transfer in 8 (2%), invasive candidiasis diagnosis in 8 (2%), and transient increase in serum transaminase levels in 4 (1%). One hundred twenty-seven infants (31%) who received fluconazole prophylaxis developed cholestasis during hospitalization, two thirds of whom had other predisposing conditions. On multivariate logistic regression necrotizing enterocolitis and increasing days of total parenteral nutrition, but not increasing number of doses on days of fluconazole, were significantly associated with the development of cholestasis.

CONCLUSION

During 4 years of fluconazole prophylaxis, the incidence of invasive candidiasis and invasive candidiasis-associated mortality rates in extremely low birth weight infants were reduced significantly, without the emergence of fluconazole-resistant Candida species.

Candida species adhesion to oral epithelium: factors involved and experimental methodology used

Due to the increasing prevalence and emergence of Non-Candida albicans Candida (NCAC) species, especially in immunosupressed patients, it is becoming urgent to deepen the current knowledge about virulence factors of these species. Adhesion of cells to epithelium is considered one of the major virulence factors of Candida species. However, relatively little is known concerning the adhesion mechanisms of NCAC species to epithelium, as well as about the factors affecting the adhesion process. This review focuses both the mechanisms that regulate the adhesion interactions and the factors involved and the description of the experimental methodology that has been used to perform the adhesion assays.

Invasive fungal infections caused by Candida and Malassezia species in the neonatal intensive care unit

Premature infants in the neonatal intensive care unit (NICU) are at particular risk of invasive fungal infections, and unfortunately, the incidence of fungal septicemia appears to be increasing. Invasive infections caused by species of Candida or Malassezia have been documented in the NICU and are often associated with significant morbidity and mortality. Controversies regarding the diagnosis, treatment, and prevention of such diseases exist. The purpose of this review is to describe the epidemiology, clinical manifestations, diagnostic techniques, treatment, and prevention of invasive infection due to Candida and Malassezia species in the neonatal intensive care setting.

Impact of fluconazole prophylaxis on incidence and outcome of invasive candidiasis in a neonatal intensive care unit

OBJECTIVES

We assessed the impact of intravenous fluconazole prophylaxis (FP) in extremely low birth weight (ELBW [<1000 g]) infants on the incidence of and outcome from invasive candidiasis (IC) in all infants admitted to a neonatal intensive care unit (NICU).

STUDY DESIGN

Beginning April 1, 2002, FP was given to ELBW infants aged < 5 days admitted to the NICU of Woman's Hospital of Texas. Infants in NICU in whom IC developed during the first 2 years of FP (FP period) were compared with those with IC during 2000-2001.

RESULTS

During 2000-2001 and the FP period, the incidence of IC in ELBW infants decreased from 7% (15 of 206) to 2% (5 of 240) (P=.01), and the IC-related mortality rate decreased from 12% (4 of 33) to 0 (0 of 40) (P=.04); the incidence of IC increased from 0.1% (4 of 2806) to 0.2% (8 of 3372) in infants of birth weight > or = 1000 g (P=.06), and no IC-related deaths occurred. During the FP period, IC developed in older infants (24 vs 12 days; P=.12) who had similar risk factors for IC.

CONCLUSION

Invasive candidiasis occurred in our NICU in spite of FP and shifted to bigger, more mature infants who had a better outcome.

Candidal arthritis after complete treatment of systemic candidiasis

Over the last few decades, the incidence of invasive candidal infections in neonatal intensive care units has increased dramatically. Various complications, such as arthritis, endocarditis, meningitis, and endophthalmitis, have been reviewed. We present the case of a premature infant with systemic candidemia. Arthritis was discovered 6 months after completion of amphotericin B therapy, and was successfully treated with oral fluconazole for 6 weeks. We conclude that long-term follow-up is particularly important in patients with treated candidemia. To prevent complications, prolonged treatment with high-dose amphotericin B is suggested for systemic fungal infection, and oral fluconazole is an effective alternative for candidal arthritis.

Enhanced killing of Candida albicans by human macrophages adherent to type 1 collagen matrices via induction of phagolysosomal fusion

Candida albicans, a component of the normal flora of the alimentary tract and mucocutaneous membranes, is the leading cause of invasive fungal disease in premature infants, diabetics, and surgical patients and of oropharyngeal disease in AIDS patients. As little is known about the regulation of monocyte/macrophage anti-Candida activity, we sought to determine if fungicidal activity might be regulated by extracellular matrix proteins to which monocytes/macrophages are adherent in vivo. Compared to monocyte/macrophages that adhered to plastic, human monocytes and monocyte-derived macrophages that adhered to type 1 collagen matrices, but not to fibronectin, vitronectin, or laminin, demonstrated a significant increase in candidacidal activity. The enhancement of monocyte fungicidal activity was maintained over a 4-h period, whereas macrophage fungicidal activity was maximum at 1 h. Although adherence of monocytes and macrophages to collagen matrices concomitantly enhanced the production of superoxide anion, only the fungicidal activity of collagen-adherent monocytes was partially blocked by superoxide dismutase and catalase. Remarkably, we found that only 10% of the phagosomes in C. albicans-infected macrophages that adhered to plastic fused with lysosomes. In contrast, 80% of yeast-containing phagosomes of collagen-adherent macrophages fused with lysosomes. These data suggest that nonoxidative mechanisms are critical for human macrophage anti-Candida activity and that C. albicans pathogenicity is mediated, in part, by its ability to inhibit phagolysosomal fusion in macrophages.

Assessment of nephrotoxicity in patients receiving amphotericin B lipid complex: a pharmacosurveillance study in Spain

This study assessed the risk of haematological, renal and hepatic toxicity associated with amphotericin B lipid complex (ABLC; Abelcet) in a multicentre, open-label, non-comparative study of 93 patients from 17 different hospitals who received ABLC because of proven or suspected systemic fungal infection or leishmaniasis. Most (66%) patients had onco-haematological diseases. Optimum treatment with ABLC comprised a slow (2-h) infusion dose of 5 mg/kg/day for a minimum period of 14 days. Biochemical and haematological parameters were measured pre-, during and post-treatment. In the overall patient group, the mean serum creatinine concentration was similar pre- and post-study (1.00 +/- 1.14 mg/dL vs. 1.20 +/- 1.19 mg/dL; p > 0.05). There were no significant changes pre- and post-treatment in concentrations of haemoglobin, potassium, transaminases and bilirubin. There was no significant correlation between the dose administered and the concentrations of serum creatinine (Spearmann 0.22). There was no greater nephrotoxicity in the patients with previous renal failure, or in those who had received amphotericin B previously. There were serious adverse events in five patients, but other alternative causes that could explain these events were present in three of these patients. Fevers or chills were experienced by 23% of the patients during the ABLC infusion, but only in one case did this necessitate the suspension of treatment. It was concluded that ABLC is a drug with low nephrotoxicity, even when administered to patients with pre-existing renal insufficiency. Adverse events were generally slight or moderate, and were managed easily with appropriate pre-medication.

Genotyping analysis of colonizing candidal isolates from very-low-birthweight infants in a neonatal intensive care unit

To analyse the relatedness of colonizing candidal isolates from very-low-birthweight infants hospitalized in a neonatal intensive care unit (NICU), we prospectively collected 86 candidal isolates from 20 infants, including 67 isolates of Candida albicans from 15 infants, 17 isolates of Candida parapsilosis from five infants and two isolates of Candida glabrata from one infant, who also had C. albicans colonization, over a one-year period. All 86 isolates were genotyped by infrequent-restriction-site polymerase chain reaction (IRS-PCR) and electrophoretic karyotyping (EK) with pulsed-field gel electrophoresis. A total of 15 genotypes were identified by IRS-PCR and 12 genotypes by EK. Some infants shared a common genotype. From a single infant, an identical genotype was found in 11 of 13 cases where at least two isolates of same Candida species were available for genotyping analysis, regardless of anatomical site, how many isolates were recovered or how many times. Should an infant harbour a candidal strain, they may harbour this strain at multiple sites and for a prolonged period.

Utility of anaerobic blood cultures in a pediatric emergency department

OBJECTIVES

To determine the frequency with which clinically significant bacterial pathogens are isolated only from the anaerobic blood culture medium in children evaluated for bacteremia and to describe the clinical features associated with these positive cultures.

METHODS

Retrospective review of all blood cultures received from the emergency department in the microbiology laboratory. Clinically significant pathogens were defined as microorganisms that rarely are considered to be contaminants or microorganisms that are recovered from multiple blood cultures or sites from the same individual. Charts of all patients with positive anaerobic cultures for clinically significant pathogens in the presence of negative aerobic cultures were reviewed. The setting was an urban tertiary care pediatric emergency department.

RESULTS

2675 paired blood cultures were performed between January 1, 1998 and December 31, 2000. Growth of a bacterial organism occurred in 595 of the paired samples. Two hundred seventy-eight were clinically significant pathogens. One hundred sixty-two (58.3%) were present in both the aerobic and anaerobic mediums, 85 (30.6%) were only in the aerobic medium, and 31 (11.2%) were only in the anaerobic medium. Most patients with growth only in the anaerobic medium had underlying conditions (ie, central venous line, immunocompromised, congenital heart disease, liver disease, age < 3 months). No obligate anaerobic organisms were detected.

CONCLUSIONS

In a pediatric emergency department setting, almost all pathogenic bacteria were isolated from aerobic culture mediums in otherwise healthy children. The yield of routinely performed anaerobic blood cultures is low. In previously healthy children, it may be optimal to inoculate the entire blood volume obtained into the aerobic medium.

Ventilator-associated pneumonia in extremely preterm neonates in a neonatal intensive care unit: characteristics, risk factors, and outcomes

OBJECTIVE

To determine the rates, characteristics, risk factors, and outcomes of ventilator-associated pneumonia (VAP) in extremely preterm neonates in a neonatal intensive care unit (NICU).

METHODS

A prospective cohort study was conducted at the St Louis Children's Hospital on all patients who had birth weight <or=2000 g and were admitted to the NICU for >or=48 hours from October 2000 to July 2001. Extremely preterm neonates were defined as neonates with estimated gestational age (EGA) <28 weeks. The primary outcome was the development of VAP. Secondary outcomes were death and NICU length of stay (LOS). Multiple logistic regression was performed to determine independent predictors for VAP and mortality.

RESULTS

A total of 229 patients were enrolled. Sixty-seven (29%) had EGA <28 weeks. Nineteen episodes of VAP occurred in 19 (28.3%) of 67 mechanically ventilated patients. VAP rates were 6.5 per 1000 ventilator days for patients with EGA <28 weeks and 4 per 1000 ventilator days for EGA >or=28 weeks. By multivariate analysis, bloodstream infection before VAP (adjusted odds ratio: 3.5; 95% confidence interval [CI]: 1.2-10.8) was an independent risk factor for VAP after adjustment for the duration of endotracheal intubation. Ventilator-associated pneumonia (adjusted odds ratio: 3.4; 95% CI: 1.2-12.3) was an independent predictor of mortality. A strong association between VAP and mortality was observed in neonates who stayed in the NICU >30 days (relative risk: 8.0; 95% CI: 1.9-35.0). Patients with VAP also had prolonged NICU LOS (median: 138 vs 82 days).

CONCLUSIONS

VAP occurred at high rates in extremely preterm neonates and was associated with increased mortality. Additional studies are needed to develop interventions to prevent VAP in NICU patients.

Colonization and epithelial adhesion in the pathogenesis of neonatal candidiasis

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.

Candidal renal and urinary tract infection in neonates

Candida species are a common cause of urinary tract infection in newborns requiring intensive care. Renal candidiasis is frequently associated with these urinary tract infections and is manifest by "fungus balls" or renal parenchymal infiltration. Candidal urinary tract infections in high-risk newborns are often associated with candidemia, thereby warranting systemic antifungal therapy. Sonography is useful in diagnosing renal candidiasis, obstruction from "fungus balls," and abscesses. The sonographic appearance of "fungus balls" may persist long after clinical resolution of Candida infection in neonates and should not affect duration of antifungal therapy. Amphotericin B is currently the drug of choice for neonates with renal candidiasis and candidal urinary tract infection. Surgical management should be reserved for decompression of obstructive candidiasis and drainage of abscesses.

An outbreak of candidemia due to Candida tropicalis in a neonatal intensive care unit

An outbreak of candidemia due to Candida tropicalis involving 16 neonates (gestational age 28-36 weeks) is reported. All infants had received hyperalimentation and at least one course of antibiotics. The commonest clinical manifestations included episodes of acute respiratory distress and lack of response to antibacterial antibiotic therapy. Candida tropicalis was recovered from blood in all the 16 infants and urine cultures were positive in 14 infants. Environmental sampling yielded C. tropicalis from one each of the blankets and mattresses used for neonates. Four of five urinary tract isolates and both environmental isolates genotyped by arbitrarily primed-PCR with several random primers were shown to belong to the same genotype.

Neonatal Candida meningitis

Candida: spp. are becoming one of the most common pathogens associated with sepsis in the setting of neonatal intensive care. Invasive therapies aimed at improving patient survival, particularly among premature infants, contribute significantly to this alteration in the distribution of neonatal pathogens. Prematurity is one of the principle risk factors associated with the development of neonatal meningitis in this patient population. Untreated, neonatal candidal meningitis is associated with a poor outcome both in terms of morbidity and mortality. However, early diagnosis with timely initiation of antifungal therapy will improve outcome significantly. The following review outlines the pathogenesis, clinical features, diagnosis, and current treatment options for neonatal candidal meningitis.

Detection of fungemia by polymerase chain reaction in critically ill neonates and children

OBJECTIVE

To compare polymerase chain reaction (PCR) with blood culture for the detection of fungemia in neonatal and pediatric intensive care unit patients.

STUDY DESIGN

A total of 0.2 to 0.5 ml of blood was collected simultaneously with blood culture in patients with suspected sepsis. Following DNA extraction, the gene for fungal 18S rRNA was amplified and PCR products analyzed by agarose gel electrophoresis.

RESULTS

Of 70 patient samples, nine of nine with a positive blood culture for Candida were PCR positive, and one of four with a positive blood culture for Malassezia was PCR positive. In total, 13 of 57 samples with negative blood culture for fungus were PCR positive. Seven of these 13 patients had other evidence of invasive fungal disease. In contrast, none of the 44 blood culture-negative/PCR-negative patients had other evidence of fungal infection.

CONCLUSIONS

PCR may be a useful adjunct to blood culture for the rapid detection of fungemia in high-risk patients.

Candida (amphotericin-sensitive) lens abscess associated with decreasing arterial blood flow in a very low birth weight preterm infant

In this report, we review the case of a candidal lens abscess in a premature infant girl who was 28 weeks' gestational age at birth. The culture obtained from the lens abscess grew Candida albicans sensitive to amphotericin B but resistant to flucytosine. This case is unique in that the infant developed a fungal lens cataract at 34 weeks' postconceptional age during the last week of a 30-day course of amphotericin B. The embryonic hyaloid artery system, which perfuses the developing lens, regresses between 29 and 32 weeks of gestation; thus, the mechanism for an infection of the lens may be inoculation of the lens by Candida before hyaloid artery system regression, followed by developmental loss of this blood supply, which makes the lens inaccessible to antimicrobial penetration. Candidal endophthalmitis with lens abscess is an uncommon morbidity that requires prompt recognition and surgical intervention for effective management.

Cecal colonization and systemic spread of Candida albicans in mice treated with antibiotics and dexamethasone

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.

Candida albicans is phagocytosed, killed, and processed for antigen presentation by human dendritic cells

Candida albicans is a component of the normal flora of the alimentary tract and also is found on the mucocutaneous membranes of the healthy host. Candida is the leading cause of invasive fungal disease in premature infants, diabetics, and surgical patients, and of oropharyngeal disease in AIDS patients. As the induction of cell-mediated immunity to Candida is of critical importance in host defense, we sought to determine whether human dendritic cells (DC) could phagocytose and degrade Candida and subsequently present Candida antigens to T cells. Immature DC obtained by culture of human monocytes in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4 phagocytosed unopsonized Candida in a time-dependent manner, and phagocytosis was not enhanced by opsonization of Candida in serum. Like macrophages (Mphi), DC recognized Candida by the mannose-fucose receptor. Upon ingestion, DC killed Candida as efficiently as human Mphi, and fungicidal activity was not enhanced by the presence of fresh serum. Although phagocytosis of Candida by DC stimulated the production of superoxide anion, inhibitors of the respiratory burst (or NO production) did not inhibit killing of Candida, even when phagocytosis was blocked by preincubation of DC with cytochalasin D. Further, although apparently only modest phagolysosomal fusion occurred upon DC phagocytosis of Candida, killing of Candida under anaerobic conditions was almost equivalent to killing under aerobic conditions. Finally, DC stimulated Candida-specific lymphocyte proliferation in a concentration-dependent manner after phagocytosis of both viable and heat-killed Candida cells. These data suggest that, in vivo, such interactions between DC and C. albicans may facilitate the induction of cell-mediated immunity.

Should central venous catheters be removed as soon as candidemia is detected in neonates?

BACKGROUND

Controversy exists regarding the most appropriate acute management of central venous catheters (CVCs) in neonates with candidemia, with up to two thirds of neonatologists preferring to attempt antifungal therapy without removing CVCs.

OBJECTIVE

To determine whether CVCs should be removed as soon as candidemia is detected in neonates. Methods. A cohort study of candidemia and CVC was conducted in infants in a neonatal intensive care unit (NICU) over a 5-year period (1994-1998).

RESULTS

Fifty infants had early-removal CVC (ER-CVC) within 3 days and 54 infants had late-removal CVC (LR-CVC) >3 days after the first positive blood culture for Candida species. All infants were treated with amphotericin B. There was no significant difference between infants in the ER-CVC and LR-CVC groups in terms of gender, ethnicity, birth weight, gestational age, age at candidemia, severity-of-illness scores, distribution of types of CVC, or in the distribution of Candida species causing candidemia. The ER-CVC group had significantly shorter duration of candidemia (median: 3 days; range: 1-14 days), compared with the LR-CVC group (median: 6 days; range: 1-24 days). The case fatality rate of Candida albicans candidemia was significantly affected by the timing of CVC removal: 0 of 21 (95% confidence interval [CI]: 0-14) infants died in the ER-CVC group in contrast to 9 of 23 (39%; 95% CI: 19-59) in the LR-CVC group.

CONCLUSION

Failure to remove CVC as soon as candidemia was detected in neonates was associated with significantly increased mortality in C albicans candidemia and prolonged duration of candidemia regardless of Candida species.

When to suspect fungal infection in neonates: A clinical comparison of Candida albicans and Candida parapsilosis fungemia with coagulase-negative staphylococcal bacteremia

OBJECTIVES

To determine the epidemiology of candidemia in our neonatal intensive care unit; to compare risk factors, clinical presentation, and outcomes for neonates infected with Candida albicans, Candida parapsilosis, and coagulase-negative staphylococcus (CoNS); and to suggest a rational approach to empiric antifungal therapy of neonates at risk for nosocomial infection.

DESIGN

Retrospective chart review of all neonatal intensive care unit patients with systemic candidiasis or CoNS infection between January 1, 1995 and July 31, 1998 at Duke University Medical Center.

RESULTS

Fifty-one patients were reviewed. Nine of 19 patients infected with C parapsilosis and 5 of 15 patients infected with C albicans died of fungemia. Seventeen neonates had >2 positive cultures for CoNS obtained within 96 hours and 1 died. There was no statistically significant difference in birth weight, gestational age, or age at diagnosis between patient groups; however, candidemic patients had a sevenfold higher mortality rate. Before diagnosis, candidemic patients had greater exposure to systemic steroids, antibiotics, and catecholamine infusions. Of the 51 patients, 32 received third-generation cephalosporins in the 2 weeks before diagnosis and 19 did not. Twenty-nine of the 32 who were treated with third-generation cephalosporins subsequently developed candidemia, while candidemia occurred in only 5 of 19 patients who were not treated with cephalosporins. At the time of diagnosis, candidemic patients were more likely to have required mechanical ventilation and were less likely to be tolerating enteral feeding. Multivariate clustered logistic regression analysis revealed that candidemic patients had more exposure to third-generation cephalosporins. Once the clinician was notified of a positive blood culture for Candida, patients infected with C parapsilosis retained their central catheters longer than patients infected with C albicans.

CONCLUSIONS

In this retrospective review, we were able to identify aspects of the clinical presentation and medication history that may be helpful in differentiating between candidemia and CoNS bacteremia. Those key features may be used by clinicians to initiate empiric amphotericin B therapy in premature neonates at risk for nosocomial infections. Prolonged use of third-generation cephalosporins was strongly associated with candidemia. There was no statistically significant difference in the morbidity and mortality between patients infected with C parapsilosis and those infected with C albicans. Observed delays in removal of the central venous catheter may have contributed to finding a mortality rate from C parapsilosis that was higher than was previously reported.

Invasive Candida enteritis of the newborn

Three premature infants (<800 g) showed invasive Candida at the site of their intestinal perforations. This entity is distinct from Candida peritonitis complicating necrotizing enterocolitis and was uniformly fatal. Recognition and aggressive antifungal therapy may improve outcomes.

Systemic Candida infection in extremely low birth weight infants: short term morbidity and long term neurodevelopmental outcome

OBJECTIVE

To describe mortality, morbidity at discharge and neurodevelopmental outcome at 2 years corrected age in extremely low birth weight infants with systemic Candida infection during intensive care stay.

METHOD

We identified all extremely low birth weight (birth weight <1000 g) infants diagnosed with Candida sepsis and/or meningoencephalitis between 1988 and mid-1996 in the tertiary neonatal intensive care centers of Toronto. The outcome of the infected infants at discharge and at 2 years corrected age was compared with a cohort of 470 extremely low birth weight infants born between 1990 and 1994.

RESULTS

Forty-six extremely low birth weight infants with systemic Candida infection, mean (+/-SD) gestational age of 24.7 +/- 1.6 weeks and birth weight 699 +/- 135 g, were identified. Case fatality rate was 37% (17 of 46), not significantly different from the control group (35%). Data on 27 infected survivors were available at discharge. All had chronic lung disease compared with 33% in the control cases (P = 0.0001), a high incidence of periventricular leukomalacia (26% vs. 12%, P = 0.06) and an increase in severe retinopathy of prematurity (22% vs. 9%, P = 0.04); 60% had adverse neurologic outcomes at 2 years corrected age compared with 35% in the control group, and 41% vs. 12% had severe disabilities (P = 0.005). Cranial ultrasound examination was the only diagnostic modality in 5 of 13 (38%) cases with central nervous system Candida involvement. All infants with brain parenchymal lesions detected by cranial ultrasound had poor outcome. Early diagnosis and commencement of antifungal treatment favorably affected the outcome.

CONCLUSIONS

Systemic Candida infection is associated with increased short and long term morbidity in extremely low birth weight infants. Candida infection of the central nervous system has a significant impact on long term neurodevelopmental outcome. Performance of cranial ultrasound examination is recommended as a part of the diagnostic investigation in these infants. Detection of brain parenchymal involvement might provide further information to predict outcome.

Systemic candidiasis in extremely low birth weight infants receiving topical petrolatum ointment for skin care: a case-control study

BACKGROUND AND OBJECTIVE

An increase in the incidence of systemic candidiasis (SC) followed a change in skin care for extremely low birth weight (ELBW) infants in our neonatal intensive care unit (NICU). We sought to determine whether the use of topical petrolatum ointment (TPO) for skin care of ELBW infants was associated with risk for SC.

STUDY DESIGN

Case-control study.

SETTING

A 48-bed NICU in a private hospital in Houston, Texas.

PATIENTS

Ten ELBW infants with and 30 without SC admitted to the NICU from December 1, 1997 through July 31, 1998.

METHODS

ELBW infants with SC were identified using hospital microbiology and infectious disease consultation databases. A case was defined as an infant weighing </=1000 g at birth with Candida spp isolated from a normally sterile body site. Three infants without SC were matched to each case by birth weight, admission date, and survival to the age of SC onset for the case. Data were collected by retrospective medical record review. Molecular analysis of Candida isolates was performed by karyotyping and restriction fragment length polymorphism using pulsed-field gel electrophoresis.

RESULTS

Case infants had a mean (+/- standard deviation) age of onset of 21.5 +/- 24 days. Infants with SC and controls did not differ in birth weight, gestational age, or duration of therapy with steroids, antibiotics, insulin, or total parenteral nutrition. Although cases were more likely to be born vaginally and had a longer duration endotracheal intubation than controls, these differences were not significant. The odds ratio for skin care with TPO in case infants versus control infants was 11 (95% confidence interval: 1.9-63). Skin care with TPO was discontinued and the incidence of SC decreased to baseline. Several Candida spp and genetic profiles were identified, suggesting that there was not a common source outbreak.

CONCLUSIONS

We conclude that the use of TPO promoted an increase in the incidence of SC in ELBW infants. Additional investigation of potential infectious risks for ELBW infants receiving TPO skin care is warranted.

Candidaemia in special care nurseries: comparison of albicans and parapsilosis infection

OBJECTIVES

Candidaemia caused by Candida parapsilosis (CP) is being increasingly reported among infants in neonatal intensive care units (NICU). To assess relative severity, clinical manifestations of candidaemia caused by C. albicans (CA) and CP in a NICU were compared.

METHODS

Between January 1994 and July 1997, episodes of candidaemia occurring among infants hospitalized in the NICU were identified in a children's hospital. The demographic characteristics, associated risk factors, clinical manifestations and outcome of the infants with CP fungaemia were collected and compared with those of the infants with CA fungaemia.

RESULTS

Twenty-four episodes caused by CA and 22 episodes caused by CP were included in this study. No significant differences were found between the two groups for gestational age, birth weight, male gender, post-natal age at onset of candidaemia, frequency of antecedent neonatal events, prior duration of antibiotic therapy and hyperalimentation, as well as presence of central venous catheter (CVC). Infants with CA fungaemia were significantly more likely than those with CP fungaemia to present with hypoxaemia, bradycardia and respiratory distress requiring intubation, and have a longer prior duration of indwelling CVC and a higher dissemination rate. The eradication rate of candidaemia and overall case fatality rate were comparable in both groups. but CP fungaemia did not appear to cause acute lethal events.

CONCLUSION

The presenting signs of CP fungaemia are relatively not so severe, but CP fungaemia, which is relatively difficult to eradicate, increases the morbidity and mortality of the infants.

Candidal mycetoma in the neonatal kidney

OBJECTIVE

To determine the natural history of renal mycetoma (fungal balls) in the neonate.

DESIGN

Retrospective chart review of all neonatal intensive care unit patients with systemic candidiasis and sonographic evidence of renal mycetoma admitted to the Duke University Medical Center between January 1, 1993, and July 1, 1998.

RESULTS

Fourteen patients were reviewed. Three died from fungemia, and 3 died from other causes months after completing treatment. Ten patients had urine cultures obtained within 1 week of diagnosis; each had a positive routine or fungal urine culture for candida. The rate of improvement of renal mycetoma by ultrasound was variable, ranging from 10 days to 4 months and was not predictive of survival or long-term renal function. All patients who were discharged from the hospital had creatinine </=0.5 mg/dL on discharge. Only 1 patient had surgical intervention (nephrostomy tube placement). Of the 11 patients who survived fungemia, 7 were treated for 3 weeks from the time negative cultures were obtained, while 4 were treated for 5 weeks or more after negative cultures. A declining platelet count was suggestive of fungemia in the patients we reviewed.

CONCLUSIONS

For our patients with renal mycetoma without complete obstruction (patients continued to have urine output) surgical intervention was rarely necessary, the rate of sonographic improvement neither correlated with clinical course nor necessitated longer therapy, and long-term creatinine levels were normal. Sustained declines in platelet count of 10% per day or more in a neonate on broad-spectrum antibiotics for suspected sepsis may be indicative of fungemia.

Candida isolates from neonates: frequency of misidentification and reduced fluconazole susceptibility

Systemic candidiasis affects 1.6 to 4.5% of very low birth weight (</= 1,500 g) infants. A specimen archive of Candida strains from intensive care nurseries was created; it currently houses 98 isolates from 17 institutions. Eight isolates (8.2%) were misidentified at the referring institution. The MICs of fluconazole for seven isolates (7.1%, all non-C. albicans species, one misidentified initially) were >8 microg/ml.

Candida infections in newborns: a review

Despite adequate treatment, nosocomial fungal infections have become an increasingly important cause of morbidity, extended hospitalization, and mortality in critically ill newborn babies. Furthermore, the high incidence of central nervous system involvement in septic newborns frequently results in serious neurological damage and psychomotorial sequelae. The prevention of fungal colonization in the population at risk, together with prompt diagnosis and treatment, are an efficient combination which lead to a better outcome of neonatal fungal infections. New drugs characterized by great efficacy and tolerance have recently been employed in clinical practice. This article summarizes certain aspects of Candida spp. infections in the neonatal period with regard to multisystemic presentation and involvement.

Systemic infection following intravenous inoculation of mice with Candida albicans int1 mutant strains

The Candida albicans gene INT1 is associated with epithelial adhesion, hyphal formation, and virulence. C. albicans strains carrying two, one, or no functional INT1 alleles were used to assess the association between mortality and C. albicans persistence in the liver and kidney of intravenously inoculated mice. Mice were injected with 10(5) C. albicans CAF2 (parent strain, INT1/INT1), C. albicans CAG3 (homozygous disruptant, Int1/int1), or C. albicans CAG5 (heterozygous reintegrant, int1/int1 + INT1). Mortality was monitored and mice were sacrificed on Days 1, 7, 14, and 21 for quantitative analysis of kidney and liver microbes, with histologic analysis of these tissues as well. Mortality was highest for mice injected with the wild-type strain CAF2 (INT1/INT1) and lowest for mice injected with the homozygous disruptant CAG3 (int/int1). Yeast were readily cleared from the liver of all mice injected with any of the three C. albicans strains. Although the mutant strains CAG3 and CAG5 are defective for hyphal formation in vitro, there was histological evidence of abundant hyphal formation in the renal pelvis of mice injected with these strains. Compared to the wild-type strain, mutant strains were associated with reduced mortality but increased C. albicans persistence in the kidney. Thus, the absolute ability to form hyphae in the kidney did not appear to modulate either C. albicans-induced mortality or the course of progressive infection in the kidney. In addition, reduced virulence was paradoxically associated with increased, not decreased, persistence of C. albicans in the kidney.

Outbreak of Candida parapsilosis fungemia in neonatal intensive care units: clinical implications and genotyping analysis

During a 5-month period, 17 infants hospitalized in neonatal intensive care units of a medical center and a branch hospital developed 18 episodes of Candida parapsilosis fungemia. The mean age at onset was 35 days. Prior to fungemia, all the infants had received hyperalimentation and antibiotics, and 15 infants had had central venous catheters. The presenting symptoms were variable but only vague in 40% of the episodes. Despite administration of antifungal agents, subsequent eradication of fungemia was achieved in only two-thirds of the episodes. None of the environmental samples was positive for C. parapsilosis, while 20% of hand-washing samples of staff working in both units yielded this microorganism. Four genotypes with two main types were identified from 14 outbreak strains and eight genotypes from 14 hand-washing strains, with one type predominant. The results suggest that C. parapsilosis fungemia increases the morbidity and mortality of neonates but does not cause acute lethal events. The outbreak was caused by two main genotypes, possibly via cross-infection by the hands of health care workers.

Microbial profile of neonatal infection in Coimbatore

In this study, 187 consecutive neonates suspected of having septicaemia were investigated for isolation of micro organisms. Two samples of blood were collected for isolation of aerobes and anaerobes. Cultures were positive in 75 (40%) cases. Aerobic bacteria were the major etiological agent, accounting for 93% of positives including the 8% cases showing polymicrobial etiology. Anaerobic bacteria and Candida species were isolated in 6.6% and 8% of positive cases respectively. Bacteroides fragilis (amongst anaerobic) and Staphylococcus aureus (amongst aerobic) were the predominant organisms isolated. Clinical presentations were not specifically different to distinguish aerobic from anaerobic bacteria. In the present study, 6.6% of bacteremias were due to anaerobes, hence possibility of some of the bactermias being due to anaerobes should be kept in mind while treating cases of neonatal septicaemia. For a complete microbial profile both aerobic and anaerobic cultures should be done.

Disseminated candidosis in premature twins

A unique case of disseminated candidosis in premature twins is presented where twin A developed disease soon after birth and died prior to the administration of antifungal therapy. On the other hand, twin B developed infection on the 26th day of birth but survived, though with sequelae (hydrocephalus), since he was promptly and accurately diagnosed and treated.

Management of neonatal candidiasis. Neonatal Candidiasis Study Group

OBJECTIVE

To identify areas of consensus and controversy in the management of neonatal candidiasis.

METHODS

A questionnaire was distributed to US-based members of the Pediatric Infectious Diseases Society and a sampling of US neonatologists.

RESULTS

Three hundred eighty evaluable questionnaires were returned (42% of those mailed). Ninety-five percent of respondents have cared for an infant with systemic candidiasis in the past 2 years. Fluconazole and liposomal amphotericin are used to some extent by 90 and 69% of respondents, respectively. A single blood culture positive for Candida led to a recommendation for immediate treatment by 99%; amphotericin B was the preferred therapy for candidemia (88%). More than 80% of respondents would request cerebrospinal fluid, urine and repeat blood cultures and ophthalmologic examination in the evaluation of candidemia. If a cerebrospinal fluid culture is positive, 25% would use amphotericin B alone whereas 62% would add flucytosine. For candiduria Society members chose fluconazole therapy more often than did neonatologists, 23% vs. 3.4% (P<0.001). There was no consensus concerning duration of therapy, use of an amphotericin B test dose or management of a central catheter in place during candidemia.

CONCLUSIONS

Systemic candidiasis in neonates is a frequently encountered clinical problem. There is agreement that prompt therapy with amphotericin B is required if a blood culture is positive for Candida and that such infants require additional evaluations. Other antifungals (fluconazole, liposomal amphotericin B) are used to some extent in this population. Many issues in management have no clear consensus and warrant further research.