Candida: an increasingly important pathogen in the nursery

Outbreak of Candida albicans fungaemia in a neonatal intensive care unit

During a 4-month period, 9 premature infants hospitalized in a neonatal intensive care unit (NICU) developed Candida albicans fungaemia. All 9 infants received antifungal agents. Fluconazole was administered in 7 patients and successfully eradicated this organism in 6 with no adverse effects. For epidemiological investigation, 64 environmental specimens and hand-washings of all 54 staff members involved in the NICU were examined for the presence of this organism. No C. albicans could be identified from environmental sources, while the hand-washing of 1 nurse was C. albicans-positive. Two genotyping methods, including electrophoretic karyotyping using contour-clamped homogeneous electric field gel electrophoresis and polymerase chain reaction-based direct sequencing of rRNA gene, were used in the analysis of the isolates recovered from blood cultures of the infants, the hand-washing of the nurse and 7 control isolates. Both methods yielded comparable results and revealed that all 13 isolates from infected infants as well as the isolate from hand washing of the nurse were of the same genotype while the control isolates were distinct. These results suggest that the outbreak of C. albicans fungaemia was caused by a particular strain and possibly via cross-infection. In addition, we showed that fluconazole seemed to be safe and effective in treating C. albicans fungaemia in neonates, although the data were limited.

Candidemia in a neonatal intensive care unit: trends during fifteen years and clinical features of 111 cases

OBJECTIVE

To determine changes in the incidence of candidemia in a neonatal intensive care unit (NICU) during a 15-year period (1981 to 1995) and to compare the prevalence and case fatality rates of Candida albicans and Candida parapsilosis infections.

METHODS

A retrospective study was conducted of candidemia occurring in infants in a NICU between January 1, 1981, and December 31, 1995. Cases were identified through computerized searching of a microbiology blood culture database. Candidemia was considered contributory to mortality if death occurred within 3 days of positive blood cultures or if there was autopsy evidence of disseminated candidiasis.

RESULTS

One hundred eleven cases of candidemia occurred in 107 infants, representing 1% of all NICU patients during the study period. The rate of candidemia in the NICU increased from 2.5 cases per 1000 admissions in 1981 to 1985, to 4.6 per 1000 admissions in 1986 to 1990 and to 28.5 per 1000 in 1991 to 1995 (P = 0.001). C. albicans was the predominant cause of candidemia between 1981 and 1990. C. parapsilosis was the most prevalent species between 1991 and 1995, causing 53 of 89 cases (60%). The mortality from C. albicans, 13 of 50 cases (26%), was significantly higher than the mortality from C. parapsilosis, 2 of 54 (4%) (P = 0.002; relative risk, 7; 95% confidence interval, 1.7 to 30).

CONCLUSIONS

The rate of candidemia in our neonatal intensive care unit increased >11-fold in the 15 years from 1981 to 1995; the prevalent Candida species shifted from C. albicans to C. parapsilosis; and candidemia associated with C. albicans has significantly higher mortality than with C. parapsilosis.

Nonperinatal nosocomial transmission of Candida albicans in a neonatal intensive care unit: prospective study

Nosocomial Candida albicans infections have become a major cause of morbidity and mortality in neonates in neonatal intensive care units (NICUs). To determine the possible modes of acquisition of C. albicans in hospitalized neonates, we conducted a prospective study at Grady Memorial Hospital, Atlanta, Ga. Clinical samples for fungal surveillance cultures were obtained at birth from infants (mouth, umbilicus, and groin) and their mothers (mouth and vagina) and were obtained from infants weekly until they were discharged. All infants were culture negative for C. albicans at birth. Six infants acquired C. albicans during their NICU stay. Thirty-four (53%) of 64 mothers were C. albicans positive (positive at the mouth, n = 26; positive at the vagina, n = 18; positive at both sites, n = 10) at the time of the infant's delivery. A total of 49 C. albicans isolates were analyzed by restriction endonuclease analysis and restriction fragment length polymorphism analysis by using genomic blots hybridized with the CARE-2 probe. Of the mothers positive for C. albicans, 3 of 10 were colonized with identical strains at two different body sites, whereas 7 of 10 harbored nonidentical strains at the two different body sites. Four of six infants who acquired C. albicans colonization in the NICU had C. albicans-positive mothers; specimens from all mother-infant pairs had different restriction endonuclease and CARE-2 hybridization profiles. One C. albicans-colonized infant developed candidemia; the colonizing and infecting strains had identical banding patterns. Our study indicates that nonperinatal nosocomial transmission of C. albicans is the predominant mode of acquisition by neonates in NICUs at this hospital; mothers may be colonized with multiple strains of C. albicans simultaneously; colonizing C. albicans strains can cause invasive disease in neonates; and molecular biology-based techniques are necessary to determine the epidemiologic relatedness of maternal and infant C. albicans isolates and to facilitate determination of the mode of transmission.

The treatment of systemic candidiasis in neonates with oral fluconazole

Fungal septicaemia has become a frequent problem in neonatal intensive care units. The usual treatment for this condition, amphotericin B alone or in combination with 5-fluorocytosine, is sometimes unsatisfactory, especially in neonates. We report our experience of fluconazole in neonates. Neonates who developed Candida septicaemia in the neonatal unit of Ga-Rankuwa Hospital (MEDUNSA) over a 1-year period were treated with oral fluconazole. The diagnosis was based on fungal cultures obtained from sites which are normally sterile. Blood cultures and renal, haematological and liver functions were monitored regularly. Therapy was continued for at least 1 week after the first negative culture was obtained. Twenty-one neonates were treated; the clinical and microbiological cure rate was 90.5%. No serious renal, haematological or hepatic complications were detected; mild hepatotoxicity was evidenced by elevated enzymes in a third of the children. Relapse occurred in one baby who received inadequate doses of fluconazole. Two babies died of causes unrelated to a systemic fungal infection. We conclude that fluconazole may be a safe and effective alternative for the management of systemic candidiasis in neonates. A comparative trial is necessary.

Fluconazole treatment of neonates and infants with severe fungal infections

A total of 24 neonates and infants, aged from 2 days to 10 months, received treatment with intravenous fluconazole for microbiologically documented or presumed fungal infection. The mean fluconazole dosage was 6 mg/kg/day (range 2-16 mg/kg/day) and the mean duration of therapy was 25 days (range 5-72 days). Efficacy was evaluated in neonates with proven fungal infections, as documented by the presence of pathogen at baseline. A positive clinical response was achieved in 23 of the 24 clinically evaluable patients (96%); eradication of the fungal organism was also achieved in 23 of the 24 evaluable patients (96%). Adverse events occurred in two patients (8%) but therapy was not discontinued in either patient. The present results confirm the efficacy and safety of fluconazole in the treatment of neonates and infants with severe fungal infections.

Invasive candidosis in pediatric patients

OBJECTIVE: To analyze invasive Candida infections in pediatric patients and to examine the outcome of disease. METHODS: An observational prospective study was carried out of microbiologically documented cases of invasive candidosis in neonates, infants and children at Hippokration Hospital from December 1993 to July 1995. RESULTS: Thirty-nine cases of invasive candidosis (mainly candidemia and candiduria) occurred in 38 patients aged 3 days to 14 years, 21 (54%) having occurred in patients aged <1 month. The incidence was 10.1/1000 admissions in the two neonatal departments versus 1.1/1000 for all other pediatric departments, including oncology (p<0.01). The most frequent causes of hospitalization were premature birth or perinatal problems and surgery. Thirty-five strains of Candida albicans, 10 of C. parapsilosis and eight of other or unidentified species were isolated. Non-C. albicans isolates, especially C. parapsilosis and C. glabrata, exhibited higher minimal inhibitory concentrations of azoles as compared with C. albicans. Thirteen patients (34%), all candidemic, died within 0--40 days. Untreated patients more frequently had positive cultures up to time of death (p<0.0001) and died (p=0.0006). CONCLUSIONS: Invasive candidosis is frequent in pediatric patients, especially premature neonates, and is associated with increased mortality. With early diagnosis and initiation of therapy the outcome is favorable.

Identification of various medically important Candida species in clinical specimens by PCR-restriction enzyme analysis

A single primer pair amplifying a cytochrome P-450 lanosterol-14 alpha-demethylase (L1A1) gene fragment that encodes a highly conserved region was used to detect yeast DNA in clinical specimens. Positive PCR products were obtained from genomic DNAs of Candida albicans, C. parapsilosis, C. tropicalis, C. guilliermondii, C. krusei, C. (Torulopsis) glabrata, and C. kefyr. No human, bacterial, or parasitic DNA was amplified. The sensitivity was evaluated for C. albicans genomic DNA by using various DNA concentrations (200 pg to 2 fg). The amplified DNAs of Candida species with unknown P-450 L1A1 gene sequences were subcloned and sequenced. Identification at the species level was achieved by digestion of the PCR products with different restriction enzymes. A specific restriction enzyme analysis pattern was determined for each species investigated. Subsequently, we used PCR to detect specific yeast DNA directly with clinical specimens such as blood and bronchoalveolar lavage specimens. After appropriate treatment, the specimens were processed by PCR and the results were compared with those obtained by traditional diagnostic procedures such as cultures and serology. Although preliminary, the PCR results seem to correlate well, at least for blood, with those of antigen detection assays and traditional blood cultures, with a better and earlier detection of candidemia.

Multifocal osteoarthritis due to Candida albicans in a neonate: serum level monitoring of liposomal amphotericin B and literature review

A 32-week neonate weighing 2,300 g at birth with fungemia due to Candida albicans subsequently developed multifocal osteoarthritis of the lower extremities due to the same organism during therapy with amphotericin B (0.5 mg/kg/day) and flucytosine (100 mg/kg/day) to which the isolates were susceptible. Liposomal amphotericin B (3.5 mg/kg/day) was substituted for conventional amphotericin B and complete clinical and radiologic recovery as well as sterilization of affected joints were achieved with a 38-day-course (144.5 mg/kg total). Adequate drug concentrations in serum and synovial fluid were attained with liposomal amphotericin B. Nine neonates (< or = 28 days of age) with bone and/or joint infections due to Candida spp. had previously been reported in the English-language literature. To our knowledge, the present case is the first reported cure with liposomal amphotericin B. Previous cases are reviewed and the potential role of liposomal amphotericin B in this serious neonatal infection is discussed.

Do variations in molecular structure affect the clinical efficacy and safety of lipid-based amphotericin B preparations?

While amphotericin B is the drug of choice in the treatment of most fungal infections, systemic adverse reactions and dose-dependent nephrotoxicity associated with its use frequently render the conventional preparation of amphotericin unsuitable. A number of lipid-based formulations of amphotericin have been developed to overcome the limitations of the parent compound. These preparations, amphotericin B lipid complex (ABLC), amphotericin B colloid dispersion (ABCD) and liposomal amphotericin differ from one another significantly in their molecular structure. They are also considerably more expensive than the parent compound. Clinical data on their appropriate use are limited. This review looks at the differences in molecular structure of these preparations, and at the available clinical safety and efficacy data.

Candidemia in intensive care unit patients: risk factors for mortality

Aim of this study was to evaluate whether risk factors which predict the development of candidemia may also predict death in ICU patients with candidemia. During an 8-year-period all ICU patients whose blood cultures yielded Candida species (n = 40) were retrospectively evaluated in a case-control fashion. The average incidence of Candida bloodstream infections was 5.5 per 10,000 patient days, ranging from 2.4 in 1990 to 7.4 in 1994. C. albicans was the most common pathogen in candidemic patients, but the proportion of non-C. albicans strains showed an increasing trend during 1989-1993, with a major shift towards non-C. albicans species in 1994. The overall mortality of patients with candidemia was 58%. Mortality was highest in the group of patients with multi-organ dysfunction syndrome, especially among those in need of hemodialysis. Risk factors for the development of candidemia, such as age, malignancy, steroid use, i.v. catheterization, and the use of broad-spectrum antibiotics were not correlated with mortality in the ICU patients studied.

Occurrence of yeast bloodstream infections between 1987 and 1995 in five Dutch university hospitals

The aim of this study was to identify retrospectively trends in fungal bloodstream infections in The Netherlands in the period from 1987 to 1995. Results of over 395,000 blood cultures from five Dutch university hospitals were evaluated. Overall, there were more than 12 million patient days of care during the nine-year study period. The rate of candidemia doubled in the study period, reaching an incidence of 0.71 episodes per 10,000 patient days in 1995. The general increase in candidemia was paralleled by an increase in non-Candida albicans bloodstream infections, mainly due to Candida glabrata. However, more than 60% of the infections were caused by Candida albicans. Fluconazole-resistant species such as Candida krusei did not emerge during the study period. The increasing rate of candidemia found in Dutch university hospitals is similar to the trend observed in the USA, but the rate is lower and the increase is less pronounced.

Nosocomial infection with Rhizopus microsporus in preterm infants: association with wooden tongue depressors

BACKGROUND

We report four cases of cutaneous infection with Rhizopus microsporus in vulnerable preterm infants in one neonatal nursery.

METHODS

There was no overlap in hospital stay between the first two cases and an extensive programme of environmental sampling was therefore initiated, with special attention being paid to items that had close contact with infants' skin. Samples were cultured by standard techniques, including fungal culture with Sabouraud's medium. Filamentous fungi with non-septate hyphae were presumptively identified as agents of mucormycosis and referred to the Mycology Reference Laboratory, Bristol, UK, for speciation.

FINDINGS

The source of infection was identified as wooden tongue depressors, which were used on the nursery to construct splints for intravenous and arterial cannulation sites. The outbreak was ended by the removal of these items from the nursery.

INTERPRETATION

Wooden tongue depressors can be a vehicle for transmission of mucormycosis. The combination of warm, humid conditions in neonatal incubators, particularly in association with occlusive dressings, may favour cutaneous fungal invasion and put small, sick babies at risk of infection.

Cloning and expression of a gene encoding an integrin-like protein in Candida albicans

The existence of integrin-like proteins in Candida albicans has been postulated because monoclonal antibodies to the leukocyte integrins alpha M and alpha X bind to blastospores and germ tubes, recognize a candidal surface protein of approximately 185 kDa, and inhibit candidal adhesion to human epithelium. The gene alpha INT1 was isolated from a library of C. albicans genomic DNA by screening with a cDNA probe from the transmembrane domain of human alpha M. The predicted polypeptide (alpha Int1p) of 188 kDa contains several motifs common to alpha M and alpha X: a putative I domain, two EF-hand divalent cation-binding sites, a transmembrane domain, and a cytoplasmic tail with a single tyrosine residue. An internal RGD tripeptide is also present. Binding of anti-peptide antibodies raised to potential extracellular domains of alpha Int1p confirms surface localization in C. albicans blastopores. By Southern blotting, alpha INT1 is unique to C. albicans. Expression of alpha INT1 under control of a galactose-inducible promoter led to the production of germ tubes in haploid Saccharomyces cerevisiae and in the corresponding ste12 mutant. Germ tubes were not observed in haploid yeast transformed with vector alone, in transformants expressing a galactose-inducible gene from Chlamydomonas, or in transformants grown in the presence of glucose or raffinose. Transformants producing alpha Int1p bound an anti-alpha M monoclonal antibody and exhibited enhanced aggregation. Studies of alpha Int1p reveal novel roles for primitive integrin-like proteins in adhesion and in STE12-independent morphogenesis.

Targeting fungi: a challenge

Invasive fungal infections are more commonly identified in various categories of patients, mainly in cancer patients but also in those undergoing organ transplantation, patients in intensive care units, and those with AIDS. There is a great need to increase the awareness of practitioners who are still underestimating the morbidity and mortality relating to invasive fungal infections, and to stress the economic burden for the society and healthcare systems of invasive fungal infections. The list of fungal pathogens causing life-threatening complications has also increased recently, with the emergence of unusual fungi being more frequently identified in such settings. Early diagnosis of invasive fungal infections is still a major challenge for the clinician at the bedside. Identification of state-of-the-art management is also a difficult task for the clinical scientist involved in the assessment of optimal strategies to prevent and to treat those invasive fungal infections, although major progress has occurred in the last 5 years with the development of new, safe, and effective antifungal agents. Empiric therapy remains a very controversial issue that should be further investigated in high-quality clinical trials. Overall, clinical research in this difficult field requires independent and objective analysis; only large multicenter clinical trials can address these critical issues and rapidly provide convincing results leading to a better prognosis of patients with invasive fungal infections. These complications still represent too often an obstacle to successful control of severe underlying diseases. Clinical research on the appropriate ways to target fungi will not only define state-of-the-art management but also identify ineffective or redundant treatments. Such an approach will make a substantial contribution to the care of the high-risk patients within the next decade and will preserve our capacity for medical excellence.

Neonatal systemic candidiasis

Systemic candidiasis is notoriously difficult to diagnose in neonates; however, it is frequently described and has a high mortality and morbidity. It is particularly likely to occur in extremely low birthweight babies, especially those receiving long-term parenteral nutrition and antibiotics. The clinical features are non-specific. Thrombocytopenia occurs in almost all cases of systemic candidiasis, but also in about half the cases of bacterial sepsis. Empirical antifungal therapy should be considered more readily for high-risk, clinically septic, thrombocytopenic babies.

A prospective study of nosocomial infection in a neonatal intensive care unit

OBJECTIVE

To determine the incidence of and organisms responsible for neonatal nosocomial infection (after 72 h of age).

METHODOLOGY

A 1-year evaluation of 321 consecutive septic work-ups performed on 130 of 1008 babies admitted to a neonatal intensive care unit (NICU) for more than 72 h. Fifty-seven (89%) of 64 infants of birthweight 500-999 g, 36 (34%) of 105 infants 100-1499 g, 27 (6%) of 422 infants 1500-2499 g and 10 (28%) of 477 infants of birthweight > 2500 g had at least one septic work-up.

RESULTS

In addition to blood culture, the evaluations included haematological score on full blood count in 94.7%, abdominal X-ray in 48%, endotracheal tube tip culture in 32.7% and lumbar puncture in only 13.1%. Blood culture was positive on 92 occasions in 75 infants (28.7% of work-ups and 7.4% of all babies admitted). Infection status was classified as definite on 40 occasions in 30 babies, and due to contamination 52 in 45 babies. Twenty of the 30 babies with definite infection were of birthweight 500-999 g. Of the 40 definite infections coagulase-negative staphylococci (CONS) were cultured from 23 babies, Gram negative bacilli in 14 and Candida spp. in three babies. Sepsis caused or contributed to the deaths of six babies.

CONCLUSION

This study identifies infants of birthweight < 1000 g as the highest risk group for nosocomial infection especially CONS. New strategies in prevention, surveillance and treatment are required for extremely low birthweight infants.

Adhesion of Candida albicans to brain tissue of Macaca mulata in an ex vivo assay

An ex vivo adhesion assay was used to examine adhesion of Candida albicans yeast cells to brain tissue of the primate Macaca mulata. Tissues from frontal lobes and striatum (caudate, putamen, and portions of the globus pallidus) were used in the assay. Yeast cells adhered to gray matter at about six times the level of adhesion to white matter. The fungus was able to bind to different cell types within the cortex, basal ganglia, and white matter. Binding to neurons, small neurons or glia, endothelial cells, and neuropil was observed.

Bacterial and fungal infections in the neonate

Despite tremendous advances in technology, sepsis remains a major threat in neonatal intensive care. The incidence of neonatal infection ranges from 7.3 to 16 per 1,000 live births. Nurses play an important role in the recognition and treatment of the septic infant. An understanding of the classification, epidemiology, and signs and symptoms of bacterial and fungal sepsis will better position the nurse to identify the infant at risk for sepsis and to initiate supportive care.

Value of routine anaerobic blood cultures for pediatric patients

OBJECTIVE

Anaerobic bacteremia rarely occurs in children. Therefore we assessed the usefulness of routinely obtaining anaerobic blood cultures in our pediatric patients.

STUDY DESIGN

Records of 9360 paired aerobic anaerobic blood culture bottles (Bactec NR660 System) containing blood specimens from pediatric inpatients and outpatients at Duke University Medical Center, Durham, N.C., were reviewed retrospectively. Yield and speed of detection were calculated for each bottle and compared for statistical significance by the McNemar test.

RESULTS

A total of 723 clinically important microorganisms were isolated; only 15 (2.1%) were strict anaerobes. Significantly more microorganisms (p < 0.001), especially staphylococci, nonfermenting gram-negative rods, enteric gram-negative rods, and yeasts, were detected by use of the aerobic bottle. The anaerobic bottle was important in identifying an anaerobic microorganism as the cause of sepsis in only five patients, all of whom were at increased risk of having anaerobic infection.

CONCLUSIONS

Anaerobic blood cultures are rarely helpful in the majority of pediatric patients and usually show positive results only in clinical settings associated with anaerobic infection. Microorganisms that prefer an aerobic environment, such as Pseudomonas aeruginosa and yeasts, are now far more common than anaerobes in children; aerobic culturing of the entire volume of blood collected might increase the yield from pediatric blood cultures.

Resistance to antifungal agents

The marked increase in the number of patients with AIDS and other forms of immunocompromise has resulted in the emergence of fungi as predominant pathogens in many institutions. Unfortunately, with the widespread use of antifungal agents to combat these infections, reports of resistance to antifungal agents have proliferated. In the present environment, the occurrence of resistance to antifungal agents is neither rare nor of negligible clinical importance. The expanding demand for antifungal agents mandates a new sense of vigilance for resistance. Although newly proposed standards for in vitro susceptibility testing should help to remove the ambiguity surrounding quantitative measurement of fungal resistance, lessons learned in the treatment of bacteria clearly now apply to fungi also: prolonged use of an antimicrobial agent will result in the selection of resistant organisms. The enlarging spectrum of resistance to antifungal agents must prompt aggressive searches for new modes of therapy. Strategies to inhibit fungal colonization, to augment host defenses, or to develop novel antifungal agents from Pseudomonas syringae or from peptide nanotubes are helping to solve this pressing clinical need.

Evidence of nosocomial spread of Candida albicans causing bloodstream infection in a neonatal intensive care unit

Candida albicans is an increasingly important bloodstream pathogen. We investigated a cluster of bloodstream infections in the neonatal intensive care unit (NICU) to determine whether nosocomial transmission occurred. Subjects included any patient in the NICU who developed clinically significant bloodstream infection with C. albicans from January 1984 to December 1987 (N = 7). Isolates were typed by restriction fragment length polymorphism analysis using a C. albicans-specific DNA probe (27A). Four of the neonates were infected from June to August 1984 (1.4 infections per 100 admissions) (the epidemic period) versus none in the period from January to May 1984, and three in the period from September 1984 to December 1987 (0.12 infections per 100 admissions) (P = .002). Three of the four patients in the epidemic period were infected with identical strains, readily distinguished from epidemiologically unrelated strains from the NICU. We conclude that nosocomial transmission of C. albicans occurred and that neonates in intensive care units may represent one group at increased risk.

Investigation of Candida albicans transmission in a surgical intensive care unit cluster by using genomic DNA typing methods

An apparent outbreak of serious Candida albicans infections (n = 6) occurred in a surgical intensive care unit over a 4-week period. Four patients developed C. albicans bloodstream infections. An additional patient developed catheter-related C. albicans infection; the sixth patient developed an infection of cerebrospinal fluid. C. albicans was isolated from the hands of five health care workers (17%) and the throat of one health care worker (3%) during the outbreak investigation. Karyotyping and restriction endonuclease analysis of genomic DNA with BssHII of 23 C. albicans isolates from patients and the 6 health care worker isolates revealed 9 and 12 different patterns, respectively. Three of six patients appeared to be infected with the same C. albicans strain (two bloodstream infections and one cerebrospinal fluid infection). The hands of a health care worker were colonized with strain that appeared identical to an isolate from a patient prior to infection of the patient. However, restriction endonuclease analysis with SfiI found differences among the isolates determined to be identical by the other two methods. Karyotyping alone does not appear to be sufficient to differentiate between outbreak and control isolates. Restriction endonuclease analysis typing may be a more sensitive method than karyotyping alone in the investigation of a cluster of C. albicans infections. Furthermore, the use of more than one restriction enzyme may be necessary for optimal strain discrimination in restriction endonuclease analysis of genomic DNA.

Candida albicans meningitis in a 27 weeks premature infant treated with liposomal amphotericin-B (AmBisome)

We report a case of Candida albicans meningitis in a neonate born after 27 weeks of gestation. To the best of our knowledge this is the first report of a premature infant with Candida-meningitis treated with liposomal amphotericin B (AmBisome(R)). The patient did not respond well to conventional Amphotericin B, but was successfully cured with Ambisome(R). Liposomal amphotericin B was well tolerated and the baby recovered with a postinfectious hydrocephalus which necessitated a permanent ventriculo-peritoneal shunt. Six months after the infection the baby appears to have a near-normal cerebral development.

PCR identification of four medically important Candida species by using a single primer pair

A single pair of primers was used in a PCR assay to amplify and identify the DNAs from four medically important Candida species: C. albicans, C. parapsilosis, C. tropicalis, and C. (Torulopsis) glabrata. The report describes the first successful amplification of a chitin synthase-specific fragment from the four Candida species responsible for more than 90% of all cases of neonatal candidemia. The primer pair sequence was based on that from the C. albicans chitin synthase gene, CHS1 (J. Au-Young and P.W. Robbins, Mol. Microbiol. 4:197-207, 1990). Each of the four amplified products is a single band of a different size. The DNA sequence of each PCR product was determined, and four species-specific probes were synthesized. The DNAs from as few as 10 organisms in 100 microliters of plasma could be detected after amplification and Southern blot analysis. In a retrospective study of 27 paired blood samples from 16 patients with culture-proven candidemia, PCR analysis was successful at detecting and correctly identifying to the species level 26 of the 27 Candida isolates. The speed and accuracy of this PCR-based technology make it a very powerful tool for detecting and diagnosing candidemia. Implementation of this assay for analyzing blood samples should result in the more timely treatment of neonatal candidemia, thereby reducing morbidity and mortality.

Systemic fungal infections in neonates

Systemic fungal infections, previously considered to be a rare complication, are now frequently diagnosed in VLBW infants receiving intensive care. Confirming the diagnosis by laboratory tests is difficult and a high index of suspicion is required. Prompt and aggressive use of antifungal treatment is justified in a clinically septic neonate, especially those with a raised serum concentration of C reactive protein, who do not show a satisfactory response to antibiotics. The newer generation of liposomal amphotericin and azole antifungal drugs appear to be safe, effective, and well tolerated. With increasing awareness, prompt treatment, and better neonatal intensive care, the outcome of systemic fungal infection in preterm infants should improve.

Neonatal candidiasis associated with meningitis and endophthalmitis

From January 1991 to March 1993, a total of 11 infants with positive blood, urine, cerebrospinal fluid (CSF) or stool cultures of Candida albicans were found in the nursery or neonatal intensive care unit of the Chung Shan Medical and Dental College Hospital. Clinical features including respiratory deterioration, poor activity, abdominal distension and/or apnea were noted. Indwelling peripheral venous catheters had been used in all patients to provide parenteral nutrition and broad spectrum antibiotic therapy and six infants had received intravenous fat emulsions. Prolonged endotracheal intubation with mechanical ventilation had been used in eight infants. Six infants (54.5%) had meningitis, five infants (45.5%) had endophthalmitis, and two infants (18.2%) had arthritis. All 11 infants received intravenous amphotericin B therapy, and the concurrent oral administration of 5-fluorocytosine was used in the six infants with meningitis. Three infants died later. Since meningitis was recognized in 54.5% patients and endophthalmitis was recognized in 45.5% patients with systemic candidiasis, the author recommends that culture and analysis of CSF along with indirect ophthalmoscopy should be performed on all infants suspected of having systemic candidiasis.

Endotracheal colonization with Candida enhances risk of systemic candidiasis in very low birth weight neonates

OBJECTIVE

To determine whether growth of Candida from an endotracheal aspirate identifies a population of very low birth weight (VLBW; < or = 1500 gm) neonates at increased risk of systemic candidiasis.

DESIGN

Prospective evaluation with weekly cultures of endotracheal and rectal specimens to determine colonization status.

SUBJECTS

One hundred sixteen VLBW neonates (mean birth weight, 975 +/- 23 gm, estimated gestational age, 27.6 +/- 0.2 weeks) with endotracheal tubes in place who were admitted to a level III nursery between Jan. 8 and Dec. 2, 1992.

RESULTS

Of the 116 subjects, 39 infants were colonized with Candida (34%). Thirteen neonates had growth of Candida in one or more cultures of endotracheal specimens. Eleven of these could be examined, and in five systemic disease developed (disease in 5/11 vs 2/26; relative risk = 5.9; 95% confidence interval, 1.34 to 26). Eight infants were colonized with Candida in the first week of life. Seven of these could be examined, and in five systemic candidiasis developed (disease in 5/7 vs 2/30; RR = 9.3; 95% confidence interval, 2.3 to 38.0).

CONCLUSIONS

Colonization with Candida occurs frequently in VLBW infants. Progression from colonization to systemic infection is more common in the smallest neonates. Detection of colonization in the first week of life or the growth of Candida from an endotracheal aspirate identifies a group of VLBW neonates with an endotracheal tube in place whose risk of systemic candidiasis is increased. A prospective trial of intervention in this high-risk population is warranted.

The epidemiology of neonatal respiratory disease

The epidemiology of many conditions affecting the newborn infant is influenced by the health of the mother, prematurity and the effects of medical and obstetric management. In this review we have considered the role of each of these factors in seven respiratory conditions presenting in the newborn infant.

Fluconazole treatment of neonates and infants with severe fungal infections not treatable with conventional agents

Fluconazole was evaluated prospectively in 40 neonates and infants between the ages of 2 days and 3 months in whom conventional antifungal therapy was ineffective or contraindicated. The patients received therapy on an individual compassionate request basis for microbiologically documented or presumed fungal infection. The mean fluconazole dosage was 5.3 mg/kg/day (range 1-16 mg/kg/day) and the mean duration of therapy was 26 days (range 2-80 days). Efficacy was evaluated in neonates with proven fungal infection as documented by the presence of a pathogen at baseline. A positive clinical response was achieved in 97% (31/32) of the clinically evaluable patients; eradication of the fungal organism was achieved in 97% (30/31) of evaluable patients. Adverse events occurred in two patients (5%); therapy was not discontinued in either patient. These favorable safety and efficacy data are similar to results obtained with fluconazole in older children and adults.

Investigation of the sequence of colonization and candidemia in nonneutropenic patients

Among neutropenic patients with hematologic malignancies, candidemia has been shown to arise typically from autoinfection after colonization. In patients without neutropenia, we examined the similarities of strains colonizing or infecting various body sites and those subsequently causing Candida bloodstream infections. Strain similarity was examined by karyotyping and restriction endonuclease analysis of genomic DNA (REAG) by using two restriction enzymes (SfiI and BssHII). The banding patterns of 42 isolates from 19 patients were independently evaluated in a blinded fashion by three observers. The interobserver reliability measured with a generalized kappa statistic was 0.59 for karyotyping, 0.84 for REAG with SfiI, and 0.88 for REAG with BssHII (P < 0.001 for each). REAG classified the initial colonizing or infecting isolate and subsequent blood isolates as identical in 16 patients (84%). The mean duration of colonization or infection prior to a positive blood culture was 5 and 23 days in patients infected with related and unrelated isolates, respectively (P = 0.14; 95% confidence interval = -14.5 to 50.5). Karyotyping results matched the REAG results for isolates from 14 of the 19 patients (74%). In patients infected with identical isolates, the initial isolate was most frequently recovered from the urine (n = 5) or vascular catheter tips (n = 4). In the five subjects with organisms showing disparate results between the methods, karyotyping revealed different banding patterns, whereas REAG suggested that the isolates were identical. Candida colonization or infection with an identical strain frequently precedes bloodstream infection in nonneutropenic patients. Future studies should evaluate whether patients at high risk for candidemia and who have vascular catheter or urine samples that are positive for a Candida on culture should be treated empirically.

Adhesins and ligands involved in the interaction of Candida spp. with epithelial and endothelial surfaces

Adhesion of candidal species to the epithelium of the gastrointestinal or genitourinary tract stands as a critical first step in the pathogenesis of candidal infection. After colonization and replication at mucosal surfaces, Candida albicans and other pathogenic species may penetrate the mucosal barrier, enter the vascular tree, and disseminate hematogenously. The consequences of this pathogenic cascade evoke considerable morbidity and mortality, especially among immunocompromised patients. Thus, interactions of C. albicans and other candidal species with epithelium and endothelium may lead to serious consequences for the human host. This review evaluates candidate candidal adhesions for epithelial and endothelial surfaces, with emphasis on the specificity of the interaction, the inhibitors that have been employed, and the ligands that have been identified on mammalian cells or matrices. Three types of interactions are described: protein-protein interactions, lectin-like interactions, and incompletely defined interactions in which the adhesive ligand is as yet unidentified. Special attention is given to the roles of integrin-like proteins. Differences in the mechanisms of candidal attachment to epithelium and endothelium are delineated. Last, on the basis of the available literature, avenues of potentially fruitful investigation are proposed.

The management of fungal obstructive uropathy in neonates and infants

Obstructive uropathy caused by upper urinary tract fungal ball formation is an uncommon but well recognized clinical entity. The clinical course and management of an infant with unilateral fungal ball obstruction is described. Ultrasound and Tc-diaminotetraethylpentacetic acid (DTPA) renal scan contributed significantly to the diagnosis and management of this patient. Complete resolution of the obstruction was achieved by treatment with intravenous amphotericin B and oral 5-fluorocytosine. The clinical course and management of 35 patients described in the literature indicate that prematurity, use of broad spectrum antibiotics, prolonged hospital stay and the use of intravascular catheters are predisposing factors. The mortality rate is 34%. Young age, small size, the presence of candidaemia and withholding antifungal therapy are poor prognostic factors. A rational plan of treatment, extrapolated from the literature, is presented which may help to reduce the mortality rate in this condition.

Isolated left-sided intracardiac fungal mass

A left-sided fungal (Candidial) intracardiac mass was found at autopsy in a 38-day premature infant with hydrops foetalis. Such a manifestation of systemic candidiasis has not been reported previously.

Effects of antifungal therapy on inflammation, sterilization, and histology in experimental Candida albicans meningitis

To assess the effects of antifungal therapy on the course of Candida albicans central nervous system infection and inflammation, we inoculated intracisternally 10(5) CFU of C. albicans into rabbits. Fluconazole (10 mg/kg of body weight) or amphotericin B (1 mg/kg) was infused intravenously daily for 14 days. Treatment was initiated 24 h or 5 days after infection. Cerebrospinal fluid (CSF) was repeatedly obtained to culture the organisms, assess the level of inflammation, and measure drug concentrations. Brain tissue was obtained at the end of therapy for culture, drug concentration determinations, and histopathology. The median number of days of treatment required to sterilize CSF cultures was 4 days for fluconazole therapy and 1 day for amphotericin B therapy (P = 0.037). There was a significant reduction in tumor necrosis factor alpha and leukocyte concentrations in the CSF of animals treated early versus those in untreated control animals (P < 0.05 and P < 0.001, respectively; analysis of variance). Compared with treated animals, a higher proportion of cultured CSF samples from untreated animals were positive for Candida (P < 0.001). A cultured brain sample from 1 of the 12 animals treated early with amphotericin B was positive for C. albicans (P < 0.01 versus controls); cultures of brain samples from 3 of 12 animals treated early with fluconazole were positive, whereas cultures of brain samples from 10 of 12 controls were positive (P < 0.05). The mean density of C. albicans was lower in the single culture-positive amphotericin B recipient (1 x 10(1) CFU/g of brain tissue) than in those treated with fluconazole (1 x 10(3) CFU/g) and in controls (8 x 10(4) CFU/g). In animals treated late, the density of C. albicans in the brain in relation to the number of days of therapy was significantly lower in amphotericin B recipients than in those treated with fluconazole (P < 0.01) and untreated controls (P < 0.01; analysis of covariance). By histopathology, a larger proportion of untreated animals compared with those treated early demonstrated features of severe infection such as perivasculitis, ventriculitis, and evidence of fungal organisms. Compared with amphotericin B-treated rabbits, those given fluconazole had a trend toward more severe pathologic lesions. Reduced susceptibility to both fluconazole and amphotericin B was observed in the C. albicans organisms isolated from the brain of one fluconazole-treated animal. These data suggest that amphotericin B is the preferred treatment for C. albicans infections of the central nervous system.

Distinct mechanisms of epithelial adhesion for Candida albicans and Candida tropicalis. Identification of the participating ligands and development of inhibitory peptides

The yeast Candida albicans is the leading cause of disseminated fungal infection in neonates, immunocompromised hosts, diabetics, and postoperative patients; Candida tropicalis is the second most frequent isolate. Because the integrin analogue in C. albicans shares antigenic, structural, and functional homologies with the beta 2-integrin subunits alpha M and alpha X, we investigated the role of integrin analogues in epithelial adhesion of C. albicans and C. tropicalis. On flow cytometry with the monoclonal antibody (mAb) OKM1, surface fluorescence was highest for C. albicans and significantly reduced for C. tropicalis (P < 0.001). However, adhesion to the human epithelial cell line HeLa S3 did not differ for these two candidal species: specific adhesion was highest for C. albicans at 44.0 +/- 1.8%, and only slightly lower for C. tropicalis at 38.8 +/- 3.6% (P = NS). The disparity between expression of the integrin analogue and epithelial adhesion suggested distinct mechanisms for this process in C. albicans versus C. tropicalis. Preincubation of C. albicans with anti-alpha M mAbs, with purified iC3b (the RGD ligand for the integrin analogue), or with 9-15-mer RGD peptides from iC3b all inhibited epithelial adhesion significantly (P < 0.001-0.04). Purified fibronectin or fibronectin-RGD peptides failed to block C. albicans adhesion. In contrast, epithelial adhesion of C. tropicalis was significantly inhibited by purified fibronectin and its RGD peptides (P < or = 0.021), but not by iC3b nor the iC3b-RGD peptides. Both iC3b and fibronectin were identified on the surface of epithelial cells after growth in serum-free medium. A polyclonal antibody to C3 inhibited C. albicans adhesion while a control antibody to fibronectin was ineffective; the converse was true for C. tropicalis. These results indicate that the pathogenic yeasts C. albicans and C. tropicalis recognize distinct RGD ligands present at the surface of the epithelial cell and that these interactions can be differentially inhibited by defined RGD peptides containing appropriate flanking sequences.

Fungal infections in cancer patients: an international autopsy survey

In an attempt to estimate the frequency of fungal infections among cancer patients, a survey of autopsy examinations was conducted in multiple institutions in Europe, Japan and Canada. Fungal infections were identified most often in leukemic patients and transplant recipients (25% each). Fifty-eight percent of fungal infections were caused by Candida spp. and 30% by Aspergillus spp. There was considerable variability in the frequency of fungal infections in different countries. Nevertheless, this study clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.

Impaired clearance and organ localization of Candida albicans in obstructive jaundice

Sepsis is a major cause of morbidity and mortality in infants with cholestatic jaundice. This may be attributed to altered host defense mechanisms. Fungal infection frequently occurs in immunocompromised patients. This study evaluates the effect of biliary obstruction on blood clearance and organ localization of radiolabeled viable Candida albicans. Male Sprague-Dawley rats (140 to 150 g) were placed in 2 groups. Group I (n = 30) were sham-operated controls. Group II (n = 90) underwent ligation and division of the distal common bile duct (CDL). At 1, 2, and 3 weeks following CDL, 10(7) cells/mL radiolabeled viable C albicans were injected via the tail vein. The final distribution of the organisms was calculated and expressed as the mean percent of radiolabeled organisms per gram and per total organ. Blood clearance of C albicans was similarly rapid in both groups. However, there was a significant decrease in the trapping of fungi by the rat liver Kupffer cells (20.3% +/- 7.9% v control 42.5% +/- 15%; P greater than .001), and increased pulmonary localization of bacteria 3 weeks following CDL (53.6% +/- 13.2% v control 41.4% +/- 6.4%). The significant decrease in liver trapping and increased lung localization of C albicans in CDL rats, may result in systemic reemergence of fungi and play a role in the susceptibility to fungal infection in jaundiced subjects.

Molecular mimicry in Candida albicans. Role of an integrin analogue in adhesion of the yeast to human endothelium

Hematogenous infection with the yeast Candida albicans now occurs with increasing frequency in the neonate, the immunocompromised patient, and the hyperglycemic or hyperalimented host. Yeast-phase C. albicans expresses a protein that is antigenically and structurally related to CD11b/CD18, a member of the beta 2 integrins and a well-characterized adhesin for mammalian neutrophils. Both the neutrophil protein and its analogue in C. albicans have an identical affinity for the C3 ligand iC3b, and both proteins are significantly increased in expression at 37 degrees C. Given these several similarities, we therefore studied the role of the integrin analogue on C. albicans in the adhesion of the yeast to human umbilical vein endothelium (HUVE). After growth of C. albicans in 20 mM D-glucose, as opposed to 20 mM L-glutamate, flow cytometric analysis with monoclonal antibodies recognizing the alpha-subunit of CD11b/CD18 demonstrated a 25.0% increase in mean channel fluorescence (range 18.4-31.8%), as well as an increased percentage of yeasts fluorescing (P less than 0.02). This increased intensity of fluorescence, which corresponds to increased expression of the integrin analogue, also correlated with a significant increase of 30-80% in adhesion of glucose-grown C. albicans to HUVE (P less than 0.02). Blockade of the integrin analogue on C. albicans by monoclonal antibodies recognizing adhesive epitopes on neutrophil CD11b/CD18 inhibited glucose-enhanced adhesion of C. albicans to HUVE. Incubation of glucose-grown C. albicans with saturating concentrations of purified human iC3b, the ligand for CD11b/CD18, reduced adhesion of the yeast to HUVE by 49.7%, whereas BSA in equimolar concentration had no effect (P less than 0.001). These results identify a glucose-responsive integrin analogue on C. albicans as one of possibly several cellular structures that mediate adhesion of the yeast to human endothelium.

Persistent or recurrent pneumonia in Saudi children seen at King Khalid University Hospital, Riyadh: clinical profile and some predisposing factors

Children with persistent or recurrent pneumonia without an apparent cause constitute an important clinical category with much morbidity and mortality and can be perplexing and frustrating to the treating physician and the parents. To identify the clinical profile and predisposing factors in this group of patients, 18 Saudi children were studied. Their ages ranged from 3 months to 12 years (mean age 5.7 years) with male preponderance--12 boys and 6 girls (M:F ratio 2:1). About 44.4% had immune and inherited metabolic disorders. Anatomical abnormalities were found in four (22.2%). Two had measles as a predisposing factor. None had tuberculosis or pertussis. One child each had pulmonary candidiasis and laryngeal papilloma, probably contracted from their mothers as congenital infections. Though the pattern seems to follow that found in developed countries, it is noteworthy that cystic fibrosis was not identified in any of our patients.