Candidiasis

Common Child and Adolescent Cutaneous Infestations and Fungal Infections

Cutaneous infections and infestations are common among children and adolescents. Ectoparasitic infestations affect individuals across the globe. Head lice, body lice, scabies, and infestations with bed bugs are seen in individuals who reside in both resource poor areas and in developed countries. Superficial cutaneous and mucosal candida infections occur throughout the life cycle. Dermatophyte infections of keratin-containing skin and skin structures result in tinea capitis (scalp), tinea corporis (body), tinea pedis (foot), and tinea unguium (nails). Less frequent endemic fungal infections such as blastomycosis, coccidiodomycosis, and histoplasmosis may present with skin findings. This article will describe the epidemiology and transmission of these conditions as well as their clinical manifestations. The approach to diagnosis will be addressed as well as primary prevention and current therapies.

Cellular mechanisms in sepsis

Mortality remains very high among septic patients despite the advanced treatments rendered in intensive care units. The development of septic shock is multifactorial. Tissue damage and organ dysfunction may be caused not only by the microorganisms but also by the inflammatory mediators released in response to the infection. Cytokines (tumor necrosis factor, interleukin-1, interleukin-6, interleukin-8, high-mobility group box-1 protein, macrophage migratory inhibitory factor) and noncytokines (nitric oxide, platelet-activating factor, complements, and eicosonoids) may inflict tissue injury and contribute to multiple organ dysfunction and cell death (or apoptosis). Gram-negative bacteria are the most common organisms identified in septic patients. The pathological effects of gram-negative bacteria are conveyed through lipopolysaccharide derived from the bacterial cell membrane. Lipopolysaccharide activates the nuclear factor kappa B, which triggers the release of inflammatory mediators. Protein components from gram-positive bacteria, fungi, or viruses may evoke the activation of nuclear factor kappa B in a similar fashion as lipopolysaccharide. Endogenous anti-inflammatory mediators are released in response to the infection and act to control the overwhelming systemic inflammatory response. The fragile balance between negative and positive feedback on the inflammatory mediators is the key factor that modulates the cellular damage and influences the clinical outcome.

The in vivo antifungal activity of the aqueous extract from Nigella sativa seeds

The effect of an aqueous extract of Nigella sativa seeds was studied on candidiasis in mice. An intravenous inoculum of Candida albicans produced colonies of the organism in the liver, spleen and kidneys. Treatment of mice with the plant extract (6.6 mL/kg equivalent to 5 mg of estimated protein, once daily for 3 days) 24 h after the inoculation caused a considerable inhibitory effect on the growth of the organism in all organs studied. A 5-fold decrease in Candida in kidneys, 8-fold in liver and 11-fold in spleen was observed in the groups of animals post-treated with the plant extract. Histopathological examination of the respective organs confirmed these findings. These results indicate that the aqueous extract of Nigella sativa seeds exhibits inhibitory effect against candidiasis and this study validates the traditional use of the plant in fungal infections.

Secular trends of candidemia over 12 years in adult patients at a tertiary care hospital

The incidence of fungal infections has been increasing for the last 3 decades, especially among neutropenic, cancer, and critically ill patients. These infections are associated with high mortality rates. We retrospectively reviewed medical charts of adult patients with fungemia from 1989 to 2000 at our institution. The characteristics of the population groups served by the hospital were described. Of 328 patients with fungemia, we reviewed 315 (96%) medical records, and focused on those with candidemia (n = 294). The species distribution in patients with candidemia showed that the most commonly identified species were Candida albicans (66%), followed by C. glabrata (17%), and C. parapsilosis (6%). The incidence of candidemia ranged from 0.2 to 0.46 per 10,000 patient-days with the highest incidence in 1993 and the lowest in 1997. Although most studies show an increased incidence of candidemia, we observed a reduction over the study period. Furthermore, we observed no shift from C. albicans to non-albicans Candida species despite a significant increase in the use of fluconazole. The overall mortality among patients with candidemia was 44%, with the highest rate in patients over 65 years (52%). Factors independently associated with higher mortality were patient age greater than 65 years, intensive care unit admission, and underlying cancer.

Effect of prolonged fluconazole treatment on Candida albicans in diffusion chambers implanted into mice

Fluconazole is an azole agent with primarily fungistatic activity in standard in vitro susceptibility tests. The present study was undertaken to develop a diffusion chamber model system in mice in order to study the in vivo effects of prolonged fluconazole treatment on Candida albicans. Chambers containing 100 C. albicans yeast cells were implanted subcutaneously on the flanks of C57BL/6 mice and were then retrieved 6 or 14 weeks later (after fluconazole treatment for 4 or 12 weeks, respectively). Leukocyte counts demonstrated that implantation of the chambers did elicit an inflammatory response but that only small numbers of inflammatory cells were able to enter the chamber interior. Treatment with fluconazole at 10 mg/kg of body weight/day for 12 weeks not only reduced the numbers of viable organisms within the chambers compared to those in untreated mice (mean +/- standard deviation of log(10) CFU of 0.7 +/- 1.2 versus 2.3 +/- 2.0; P < 0.001 by the Bonferroni test) but also increased the numbers of chambers that became sterile over the treatment period (14 of 16 versus 6 of 19; P = 0.0009 by the chi-square test). However, treatment for only 4 weeks had minimal effects on the numbers of chamber CFU, and none of the chambers became sterile during this period. Distribution of retrieved organisms between interior fluid and the chamber filters was approximately equal in all the treatment groups. This model system appears to be useful for evaluating the effects of antifungal drugs over prolonged periods in vivo. Its use in the present study demonstrates that fluconazole can increase the rate of sterilization of C. albicans foci that are protected from the host's inflammatory response.

Fungal and parasitic infections of the eye

The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures.

Oropharyngeal candidiasis: a review of its clinical spectrum and current therapies

With the increased use of antibiotics and immunosuppressive agents, oropharyngeal candidiasis is becoming more common. This infection is also associated with such advances in medical management as chemotherapy and organ transplantation and with human immunodeficiency virus infection. Various topical and systemic agents are available to treat patients with candidiasis, but optimal management can be elusive. Treatment of uncomplicated oropharyngeal candidiasis in the immunocompetent patient involves selecting a particular formulation of a topical medication based on oral conditions, length of contact time, and taste, texture, and cost of the medication. Treatment of severe oropharyngeal candidiasis, particularly in patients with a compromised immune system, is often more difficult, and relapses are common. Reports of resistance to systemic agents, particularly in patients needing recurrent therapy, are increasing. Amphotericin B, long used as an intravenous agent, is now available as an oral suspension that may offer therapeutic benefits comparable to those of systemic therapy without the toxicity associated with systemic absorption.

Cardiac surgery in a high-risk group of patients: is prolonged postoperative antibiotic prophylaxis effective?

OBJECTIVE

In a prospective, randomized study, postoperatively prolonged antibiotic prophylaxis is evaluated in a high-risk group of patients undergoing cardiac operations. These patients had postoperative low cardiac output necessitating inotropic support and intraaortic balloon pumping.

METHODS

Between January 1991 and 1994, 53 patients were enrolled in the study (42 men, mean age 65 years). All patients received the usual perioperative (24 hours) cefazolin prophylaxis. In the study group (n = 28) a prolonged regimen of prophylaxis with ticarcillin/clavulanate was performed for 2 days and vancomycin was added in a low dose until removal of the intraaortic balloon pump. The control group (n = 25) did not receive a prolonged regimen of prophylaxis. Follow-up ended at hospital discharge.

RESULTS

Early mortality was 7 of 28 patients (25%) in the prophylaxis group and 8 of 25 patients (32%) in the control group (p = 0.397). Defined infections (pneumonia, n = 22; sepsis, n = 8; deep sternal wound infection, n = 2) occurred in 50% of the study group and 68% of the control group (p = 0.265). In all patients with septicemia, only coagulase-negative staphylococci could be isolated from the bloodstream (5 patients in the prophylaxis group vs 3 in the control group). Infectious parameters were controlled daily and did not differ significantly between groups. A total of 1158 bacteriologic tests were performed (blood cultures, n = 389; intravascular catheters, n = 208; bronchial aspirates, n = 411; intraaortic balloon pumps, n = 42; wound secretions, n = 108) showing bacterial growth in 322 (28%) without a significant difference between the groups. In the prophylaxis group, 13 intravascular catheters and intraaortic balloon pumps showed bacterial growth versus 11 in the control group. No side effects were seen.

CONCLUSIONS

In a high-risk group of patients undergoing cardiac operations, infectious outcome could not be effectively influenced by an additional and prolonged postoperative prophylaxis regimen with low-dose vancomycin and ticarcillin/clavulanate. Low-dose vancomycin did not reduce the rate of infections or colonizations of intravascular catheters with gram-positive organisms.

Intravenous injection of Candida-derived mannan results in elevated tumor necrosis factor alpha levels in serum

Intravenous injection of Candida albicans into mice produced elevated serum tumor necrosis factor alpha (TNF-alpha) levels. We hypothesized that immunostimulants released in vivo from C. albicans during fungal sepsis might contribute to the elevated levels of TNF-alpha in serum. We tested this hypothesis in mice with C. albicans mannan (CAM). Increased serum TNF-alpha levels were observed following intravenous and intraperitoneal injections of CAM. Injection of CAM into mice resulted in increased serum TNF-alpha concentrations that reached 1,200 pg/ml of blood, compared with 2,400 microg/ml of blood following injection of 10 microg of endotoxin. The response to CAM was concentration dependent, requiring a minimum dose of 20 microg of CAM per g of body weight. Sera from mice were tested 30, 60, 90, and 120 min after intravenous injections with CAM. TNF-alpha concentrations were minimal 30 and 120 min after intravenous injection and maximal 60 and 90 min after CAM injection. The relative distribution of CAM in vivo in decreasing order was determined to be as follows: blood > liver > lung > spleen, 90 min following injection of a single 5-mg dose of CAM. CAM was confirmed as the stimulating substance by utilizing anti-CAM antibodies in vivo to block the response. Rabbit anti-mannan antibodies administered by intraperitoneal injection 24 h before CAM injection significantly suppressed (P < 0.05) the accumulation of TNF-alpha in the sera. Dexamethasone administered to mice before intravenous injection of mannan significantly reduced (40 to 90% reduction; P < 0.05) the concentrations of TNF-alpha in the sera of treated mice. Thus, when in vivo CAM clearance mechanisms are exceeded, sufficient CAM may become available to stimulate TNF-alpha production, making CAM an important part of pathogenesis in Candida sepsis.

Recent progress and current problems in treatment of invasive fungal infections in neutropenic patients

Invasive fungal infections, including disseminated candidiasis and invasive pulmonary aspergillosis, are important causes of morbidity and mortality in neutropenic patients. The recent development of fluconazole, itraconazole, lipid formulations of amphotericin B, and recombinant cytokines have expanded our therapeutic armamentarium. Clinical trials have elucidated new strategies for utilizing these compounds in the prevention and treatment of opportunistic mycoses. The population of more severely immunocompromised patients, however, continues to expand and the spectrum of drug-resistant fungi, including but not limited to Candida spp, Fusarium spp, Zygomycetes, and dematiaceous moulds, continues to evolve, thus presenting new challenges to recent therapeutic advances. Development of new antifungal chemotherapeutic agents and novel approaches for augmentation of host response will be required to meet these new mycologic challenges.

Comparison of the Murex Candida albicans CA50 test with germ tube production for identification of C. albicans

A total of 502 yeast isolates were tested with the 30-min MUREX Candida albicans CA50 (Norcross, GA) test for presumptive identification of C. albicans. The results were compared with the standard 2-h germ tube test, which was the reference standard. Of the 502 isolates, 316 were C. albicans and 186 were non-C. albicans. Identifications were based on germ tube reactions; the API20C and chlamydospore agars were used when discrepant results persisted between the germ tube and MUREX test after repeat testing of the MUREX method. A total of 16 C. albicans gave negative results on initial testing with the MUREX test but were interpreted as positive when repeated. Three germ tube negative yeasts initially tested positive with the MUREX but were negative when repeated. Two additional yeast isolates gave incorrect results with the MUREX, even with repeat testing: C. albicans and C. lusitaniae. The initial sensitivity and specificity for the MUREX C. albicans CA50 test were 94.6% and 97.8%, respectively. As an addition to the study, two fetal bovine sera were compared for production of germ tubes; fetal bovine serum and Fetal Clone II. The testing found them to be in 100% agreement.

Strain relatedness of Candida albicans strains isolated from children with leukemia and their bedside parents

Candida yeasts are occasionally recovered from patients with leukemia in spite of antifungal therapy used during chemotherapy. It is not yet known whether yeasts in these patients are of endogenous or exogenous origin. We examined the strain relatedness of Candida albicans isolated from three patients with leukemia (A, B, and C) and their bedside parents using pulsed-field gel electrophoresis (PFGE), restriction fragment length polymorphism (RFLP) by SmaI digestion, and the Southern hybridization patterns of the RFLPs by the C. albicans-specific probe RPS1. SmaI digestion and Southern hybridization by RPS1 showed identical or similar patterns among Candida isolates in patients A and his mother, although their karyotypes were different. Isolates from patients B and both parents showed identical electrophoretic karyotypes, SmaI digestion patterns, and hybridization patterns. Since electrophoretic karyotypes are more variable than RFLPs and their hybridization patterns, the identity of the last two suggests a close relatedness between strains. Our results also suggest that transmission of yeast strains may have occurred between patient A and his mother and between patient B and her parents. Isolates from patient C and her mother are thought to have originated from different strains, since different patterns were obtained in electrophoretic karyotypes, SmaI digestion patterns, and Southern hybridization patterns.

Fluconazole treatment of children with severe fungal infections not treatable with conventional agents

Fluconazole was evaluated prospectively in 173 children aged between 4 months and 16 years in whom conventional antifungal therapy was ineffective or contraindicated. Children entered the study on an individual compassionate request basis for treatment of confirmed or presumed fungal infection or for prophylaxis of fungal infections. Sixty-two children had cancer, 40 had undergone transplantation, 14 had AIDS and 52 had other conditions. The mean fluconazole dosage was 3.4 mg/kg/day (range 0.16-11.1 mg/kg/day) and the mean duration of therapy was 36 days (range 1-340 days). Efficacy was evaluated in 63 children with confirmed fungal infection as documented by the presence of a fungal pathogen at baseline; clinical cure or improvement was achieved in 83% (52/63), pathogen eradication in 73% (43/59). All 173 children were assessed for safety. Related or possibly related adverse events occurred in 6% (11/173) of patients; seven children were withdrawn from therapy because of adverse events. Results of this study demonstrate that the clinical efficacy and safety profile of fluconazole in the treatment of fungal infections in children are favorable, results being similar to those obtained in adults.

Diagnosis and monitoring of disseminated candidiasis based on serum/urine D/L-arabinitol ratios

Disseminated candidiasis, a devastating disease with high morbidity and mortality in immunosuppressed patients, is difficult to diagnose because of the protean nature of symptoms and the lack of rapid and reliable laboratory diagnostic procedures. The subject of this review is the status of gas chromatographic-mass spectrometric techniques for the determination of D-arabinitol, a unique metabolite of pathogenic Candida species, in serum and urine. The enantiomers are separated by chiral chromatography followed by specific and sensitive detection using chemical ionization and selected ion monitoring. Using D/L-arabinitol ratios, instead of individual concentrations, eliminates the need for knowing the volume of samples and for calibration curves. A new filter paper technique requires only an unmeasured drop of whole blood (venous or finger/heel puncture) or urine; paper spots are mailable. Parallel determinations of D/L-arabinitol ratios in serum and urine in normal subjects and cancer patients with both normal and increased D/L-arabinitol ratios revealed constant (1.2-1.3 range) ratios of serum D/L-arabinitol/urine D/L-arabinitol for all populations studied. Analyzing two body fluids taken at the same time increases reliability by reducing false positives.

Fungal plasma membrane proton pumps as promising new antifungal targets

Fungi are widely dispersed in nature and frequently appear as pathogens in the animal and plant kingdoms. The incidence of opportunistic fungal infections in humans has increased due to the human immunodeficiency virus and the application of modern medical approaches that subvert natural protective barriers to infection. Also, fungal blights continue to threaten crops worldwide. As a result, new antifungal agents are needed to address these critical problems. Existing antifungals can be used to effectively treat most cases of topical infection caused by the opportunistic pathogen Candida albicans, which is the principal agent of nosocomially acquired fungal infections. However, life-threatening, disseminated Candida infections are treated with more modest success. Existing antifungals can be toxic or ineffective because of natural resistance or even induced resistance. This limited efficacy largely reflects the restricted range of cellular targets considered during the development of current antifungals. The advancement of highly selective fungicidal reagents requires the recognition of new essential cellular targets. The fungal plasma-membrane proton pump is a high-abundance essential enzyme with a number of well-understood molecular properties that should facilitate the development of new antifungals. The proton pump is important for intracellular pH regulation and the maintenance of electrochemical proton gradients needed for nutrient uptake. It is a member of the P-type class of ion-transport enzymes, which are present in nearly all external cellular membranes. Typical P-type enzymes such as the Na+,K(+)-ATPase and H+,K(+)-ATPase are well established as specific targets for surface-active cardiac glycosides and anti-ulcer therapeutics. The development of new classes of selective antifungals targeted to the proton pump will require exploitation of the well-characterized genetic, kinetic, topological, regulatory, and drug-interaction features of the fungal enzyme that discriminate it from related host P-type enzymes. New antifungal drugs of this type should be relevant to the control of fungal pathogens of medical and agricultural importance and may be applicable to the control of intracellular parasites that also depend on closely related proton pumps for survival.

Determination of serum arabinitol levels by mass spectrometry in patients with postoperative candidiasis

A combined gas chromatography-mass spectrometry (GC-MS) technique was used for serial determination of serum arabinitol levels in patients with postoperative candidiasis. Forty subjects were investigated, 18 patients with candidiasis, 7 patients with superficial Candida colonization and 15 postoperative control patients. The arabinitol levels were highly elevated, slightly elevated and normal in 13, 1 and 4 patients respectively with candidiasis; in 2, 2 and 3 colonized patients and in 1, 1 and 13 control patients (p < 0.001, chi 2, between all the groups). The sensitivity of a single arabinitol determination for detection of postoperative candidiasis was 27.6 % and the specificity 89.2 %. Use of multiple samples improved sensitivity up to 72.2% per patient (123 samples) with a specificity of 86.4 %. Highly elevated arabinitol concentrations were detected in only one patient before the onset of therapy. Determination of arabinitol levels by GC-MS is a specific test for diagnosing candidiasis, but multiple samples are required for adequate sensitivity, and the initiation of therapy must still be on an empirical basis.

Gastric colonization with Candida albicans

We adapted a rat model of gastrointestinal candidiasis for studies of in vivo gastric colonization with Candida albicans. Whereas normal rats cleared a single intragastric inoculum of 5 x 10(6) C. albicans from the stomach within 4 hours, rats pretreated with chloramphenicol and gentamicin achieved stable gastric colonization for at least 5 days after administration of this inoculum. We next used this model to study host modifications hypothesized to alter gastric colonization. A first group received dilute HCl 4 hr before yeast inoculation, to induce acute superficial gastric erosions; another group was treated with glucocorticosteroid beginning 12 days before yeast inoculation; and another group received famotidine therapy beginning 3 days before yeast inoculation, to neutralize gastric acidity. Recovery of yeasts from stomachs was significantly different from the control group only in rats treated with steroids; greater colonization was found in the rats so treated. In a final group of experiments, we attempted to inhibit in vivo gastric colonization with yeasts by preincubation of yeasts in vitro with a polyclonal antiserum raised in rabbits against heat-killed C. albicans. We were not able to demonstrate inhibition of gastric colonization by preincubation with this antiserum in this model system.

Candida arthritis in adult patients who are not intravenous drug addicts: report of three cases and review of the literature

Candida species are an uncommon cause of infectious arthritis, although the frequency has increased during recent years. Three cases of septic arthritis caused by Candida species are reported, and the literature is reviewed. The first patient developed a popliteal cyst infected by Candida albicans after multiple intravenous antibiotic treatments. The second patient had acute myelogenous leukemia and experienced knee arthritis after chemotherapy, and the third suffered oligoarthritis after a second heart transplantation. All patients received treatment with a standard dose of intravenous amphotericin B. Responses were achieved only in the first two cases; the third patient died despite therapy. Thirty-six previously reported Candida arthritis cases are reviewed, and epidemiologic, diagnostic, therapeutic, and prognostic features are analyzed. Cases are divided into two categories: direct inoculation of fungus and hematogenously disseminated disease; these two categories are compared in terms of sex, age, pathogen species, treatment, and survival. Arthritis induced through direct inoculation of fungus is seen in older individuals, is more frequently produced by species other than C albicans (Candida parapsilosis especially), and has a better prognosis than arthritis caused by disseminated candidiasis. Arthritis can be resolved even in the persistence of the systemic disease. It is believed that the first case of Baker's cyst infected by C albicans and the first case of Candida arthritis in a heart transplant patient are reported here.

Invasive candidiasis during granulocytopenia

Candidiasis remains the most frequently encountered fungal infection in patients with profound granulocytopenia and appears to be increasing in frequency. In addition, Candida infections are occurring earlier during remission induction chemotherapy and can be caused by a variety of species such as C. albicans, C. tropicalis, and C. krusei. The most frequent source of disseminated infection is the gastrointestinal tract, as the integrity of the epithelium is disrupted by chemotherapeutic agents. The spectrum of disseminated candidiasis comprises both an acute and a chronic presentation (also known in the literature as hepatosplenic candidiasis). The management of disseminated infection consists of early empiric antifungal therapy with a standard agent, amphotericin B. Unfortunately, responses in the setting of profound granulocytopenia appear to be poor. Other agents that appear to be useful in the management of disseminated candidiasis include 5-flucytosine and fluconazole. Based on animal experimentation, it appears that the combination of these three classes of agents might produce superior results compared with amphotericin B alone. Removal of the central venous catheter does not appear warranted in the setting of profound granulocytopenia, and the role of colony stimulating factors needs to be defined. Given the severity and high mortality associated with disseminated candidiasis in patients with hematologic malignancies, antifungal prophylaxis appears warranted.

Early Candida isolations in febrile patients after abdominal surgery

The significance of finding Candida sp. in febrile patients after abdominal surgery was studied in a prospective study on 107 patients. The patients were divided into 3 groups, based on the isolation and time of sampling of Candida sp. and on any other microbiological documentation of the infection. Eight patients were found Candida-positive either by blood cultures or by cultures of urine, abdominal pus, tracheal aspirate or wound exudate within the first postoperative week and had significantly greater mortality than patients with other infections or later Candida sp.-isolation (50% vs 10%, p < 0.05). Isolation of Candida was associated with prolonged antibiotic therapy, extended central vein catheterization, parenteral nutrition and operations on the small bowel, ascending colon or pancreas, but not with the underlying illness. The results support the view that isolation of Candida sp. within the first week after surgery does not represent harmless colonization but is rather associated with serious morbidity.

Persistence of the same Candida albicans strain despite fluconazole therapy. Documentation by pulsed-field gel electrophoresis

Candida albicans and other Candida species have emerged as major nosocomial pathogens associated with a high mortality. Therapeutic options for fungal infections are limited. Amphotericin B has been the mainstay of treatment for serious systemic candidal infections, but it is relatively toxic and associated with a variety of side effects. Fluconazole has been proposed as alternative therapy for the treatment of systemic candidiasis including candidemia. We report the case of a patient with fungemia in whom fluconazole failed to eradicate C. albicans and C. tropicalis. These pathogens were recovered from sputum and urine cultures, respectively, on day 12 of intravenous fluconazole therapy. Molecular epidemiologic techniques employing pulsed-field gel electrophoresis confirmed the persistence of the same C. albicans strain. Susceptibility studies showed a marked change in MICs of fluconazole between 24 and 48 hr, with an increase from less than or equal to 1.25 to greater than 80 micrograms/ml. Controlled trials will be needed to delineate the role of fluconazole in the treatment of disseminated candidiasis and its efficacy in comparison with amphotericin B. Amphotericin B should remain the drug of choice for such infections until data from controlled trials are available.

Torula glabrata: a severe and rare complication in patients suffering from burns

Fungal infections are assuming a more prominent role in the sepsis of patients with burns. Torula glabrata (Candida glabrata) is a fungus increasingly found in immunosuppressed patients. This report describes a seriously burned patient who developed a torula infection in the lungs.

Cloning and characterization of the plasma membrane H(+)-ATPase from Candida albicans

The Candida albicans PMA1 gene was isolated from a genomic library by using a hybridization probe obtained from the PMA1 gene of Saccharomyces cerevisiae. The gene was localized to chromosome III of the Candida genome. An open reading frame of 2,685 nucleotides predicts an amino acid sequence of 895 amino acids that is 83% homologous at both the DNA and protein levels to its S. cerevisiae equivalent. A polyadenylated mRNA transcript of about 4,000 nucleotides contains a highly folded AU-rich leader of 242 nucleotides. The structure of the gene, codon bias, and levels of approximately 100-kDa H(+)-ATPase protein recovered in plasma membranes indicate a highly expressed gene. The plasma membrane ATPase was purified to about 90% homogeneity and appeared to be blocked at the amino terminus. Three hydrophobic membrane sector tryptic fragments from the partially digested ATPase provided internal sequence information for over 50 amino acids, which agrees with the sequence predicted by the cloned gene. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the C. albicans enzyme is about 3 kDa smaller than its Saccharomyces counterpart and was consistent with a predicted Mr of 97,398. Antibodies to the S. cerevisiae whole ATPase or its carboxyl terminus bound to the C. albicans enzyme but with lower avidity. Kinetic analysis showed that the Candida and Saccharomyces ATPases respond to glucose activation-starvation in nonidentical fashions. The amino-terminal domain of the C. albicans ATPase is marked by a net deletion of 23 amino acids in comparison with the S. cerevisiae ATPase. These differences maintain net charge, occur in nonconserved regions of fungal ATPases, and are sufficient to account for the observed difference in electrophoretic mobility between the two yeast ATPases.

Fluconazole therapy for chronic disseminated candidiasis in patients with leukemia and prior amphotericin B therapy

OBJECTIVE

To study the efficacy of fluconazole against chronic disseminated candidiasis (hepatosplenic candidiasis) in patients with leukemia in whom amphotericin B treatment had failed.

DESIGN

Retrospective analysis of patients with chronic disseminated candidiasis treated with fluconazole on a compassionate investigational new drug protocol.

SETTING

Multi-institutional.

PATIENTS AND METHODS

Twenty consecutive patients received 100 to 400 mg of fluconazole per day for a median of 30 weeks. All had either failed to respond to treatment with more than 2 g of amphotericin B or had serious amphotericin B-related toxicities.

RESULTS

Fourteen of 16 evaluable patients (88%) responded. Responses were observed in seven of nine patients in whom adequate doses of amphotericin B had failed and in all seven patients who had amphotericin B-related toxicities. In 12 patients, cytotoxic chemotherapy was continued without flare of the infection. Fluconazole was well tolerated with rare side effects. Aspergillus superinfection developed in three patients and contributed to the death of two of them.

CONCLUSION

Fluconazole is a safe and effective agent with significant activity against chronic disseminated candidiasis.

Hospital-acquired diarrhea in adults: a prospective case-controlled study in Mexico

OBJECTIVE

To know the incidence, etiology, risk factors, morbidity, and mortality of nosocomial diarrhea in adults.

DESIGN

Nested case-control study, matched by service, length of stay, date of admission, and presence of leukopenia and/or the acquired immunodeficiency syndrome (AIDS). Cases were those who developed nosocomial diarrhea. Controls were those who did not develop nosocomial diarrhea during a comparative period nor during the next ten days. Stool samples were processed in search for parasites, yeasts, bacteria, and rotavirus.

SETTING

Third-level referral center, in Mexico City, Mexico, for general internal medicine and surgical problems.

PATIENTS

Eligible subjects were all new admissions to the hospital from November 1987 to September 1988. Reasons for exclusion were presence of chronic diarrheal disease or melena. There were 115 cases and 111 controls.

RESULTS

Overall risk of acquiring nosocomial diarrhea was 5.5%, or 1.8 episodes per 100 patient-weeks. A potential pathogen was found in 59%. Yeasts and Entamoeba histolytica were the most frequently isolated pathogens. Mortality in cases was 18%, as compared with 5% in controls (p less than .01). Multivariate analysis showed enteral feeding, recent enemas, presence of Candida species, use of antacids/H2-blockers, and presence of nasogastric tubes as significant risk factors for nosocomial diarrhea.

CONCLUSIONS

Diarrhea is a common complication in hospitalized patients. It occurs more often than previously suspected and is linked with a substantial mortality. The spectrum of etiologic agents is different from that reported in pediatric hospitals. Given that nosocomial diarrhea may constitute, at least, a marker of severity of illness, it should receive more attention in general hospitals.

Gastrointestinal candidiasis in a murine model of severe combined immunodeficiency syndrome

A murine model of severe combined immunodeficiency syndrome (scid mice) affords an opportunity to study the interaction of Candida albicans with a host lacking functional B- and T-cell mechanisms. We have previously reported no significant difference in yeast recovery after intravenous challenge of BALB/c mice and scid mice with C. albicans (S. Mahanty, R.A. Greenfield, W.A. Joyce, and P.W. Kincade, Infect. Immun. 56:3162-3166, 1988). In this study, we evaluate the course of gastrointestinal candidiasis after a single oral challenge with C. albicans. BALB/c and scid mice received H2O containing 10(6) C. albicans per ml for 16 h. Half the mice of each strain continuously received H2O containing 1 mg of tetracycline per ml. Stool samples were cultured for yeast twice weekly until they were negative three consecutive times or positive for 8 weeks. Mice were then sacrificed for quantitative cultures of liver, spleen, and kidneys. At eight weeks postinoculation, 2 of 13 BALB/c mice, 0 of 14 BALB/c mice receiving tetracycline, 6 of 12 scid mice, and 8 of 13 scid mice receiving tetracycline had positive stool cultures (P less than 0.05, likelihood ratio chi-square). Quantitative recovery of yeasts from stools was also higher in the scid mice. Cultures of liver, spleen, and kidneys wer negative in all BALB/c mice and essentially all negative in scid mice; a single colony was isolated from the kidney of one scid mouse and the liver of another scid mouse. We conclude that B cells and/or T cells and their products are important in gastrointestinal colonization with C. albicans but that even in their absence, dissemination of infection from the gastrointestinal tract does not consistently occur. Thus, other aspects of host defense must be critical in containing gastrointestinal Candida colonization.

Infections in the compromised child

Children receiving chemotherapy for malignant diseases show different patterns of infection depending on their underlying disease and its therapy. Granulocytopenia carries the risk of bacterial infection, and also, if prolonged, of fungal infection. Impairment of cell-mediated immunity predisposes to infections with Pneumocystis carinii and is thought to be responsible for severe primary infections with varicella and measles, as well as the severe cytomegalovirus infections seen after allogeneic bone marrow transplantation. Absence or impairment of splenic function predisposes to overwhelming septicaemia with encapsulated organisms, while defects in the normal mechanical barriers to infection provide routes for bacterial and fungal invasion. Despite the lack of physical signs of a normal inflammatory response, clinical evaluation may be critical to the localization of infection in the immunocompromised child. Blood culture and biopsy remain pivotal investigations in the achievement of a microbiological diagnosis. Empirical treatment with a combination of antibiotics has been shown in comparative studies to be effective in initial management of the febrile neutropenic patient: continuing studies are evaluating the role of monotherapy and of different antibiotic combinations, particularly in the light of changing patterns of bacterial infections. Empirical antifungal therapy has been shown to be necessary for persistent or recurrent fever, particularly as persistent fungal infection may compromise the outcome of continuing cytotoxic therapy. Continuing uncertainties over many aspects of management of the infected immunocompromised child provide scope for clinical trials in parallel with trials evaluating new anticancer regimens. The use of new diagnostic methods, the role of prophylaxis, the most appropriate empirical regimen, the evaluation of new antimicrobial agents, all require careful evaluation for efficacy and safety. Perhaps the greatest dilemma of all is how far results from trials in adults can be extrapolated to paediatric practice.

Characterization of the sequence of colonization and nosocomial candidemia using DNA fingerprinting and a DNA probe

The objective of this hospital-based study was to determine the relationship between colonizing and infecting strains of Candida species and Torulopsis glabrata. Surveillance cultures from high-risk patients were paired with subsequent bloodstream isolates. Organisms were typed by using restriction endonuclease digestion of chromosomal DNA with BstNI and EcoRI, followed by Southern hybridization with a DNA probe (pBD4) derived from Saccharomyces cerevisiae. Sixteen patients for whom documented colonization preceded documented bloodstream infection were identified. The mean time between obtainment of surveillance isolates and obtainment of bloodstream isolates was 8 days, with a range of 1 to 423 days. For 15 (94%) of 16 patients, the DNA fingerprint pattern (using BstNI) of the surveillance isolate was identical to that of the bloodstream isolate. Isolates from 13 (81%) of 16 patients were unique to those patients. Typing by Southern hybridization with the pBD4 probe was less discriminating. We conclude that for a well-defined subset of hospitalized patients who were colonized by Candida species before developing nosocomial candidemia, the colonizing and infecting strains were identical, suggesting endogenous acquisition of infection. Restriction endonuclease digestion of chromosomal DNA was shown to be a discriminating and reproducible typing method for Candida species and T. glabrata.