Severe candidal infections: clinical perspective, immune defense mechanisms, and current concepts of therapy

Acute oral candidiasis during febrile episodes in immunocompromised patients with haematologic malignancies

To estimate clinical, pathogenic and serological aspects of acute oral candidiasis (AOC) during febril episodes in patients with haematologic malignancies, 23 consecutive patients who developed AOC within 7 days from start of fever were compared with 23 consecutive patients who did not develop AOC. The duration of fever and severe granulocytopenia (less than 0.5 x 10(9)/l) was significantly longer in patients with AOC than in patients without AOC, the median differences between the patients with and without AOC being 4 and 3 days, respectively. Development of AOC could not be correlated to a change in the qualitative composition of the oral microflora. The thrombocyte count was lower in patients with AOC on day 4, whereas no differences were found in leukocyte counts. The prevalences of Candida albicans agglutinin titres greater than or equal to 5 were similar in patients with (24%) and without AOC (33%), and in controls (29%). Seroconversion or a significant increase in the agglutinin titre occurred in 4 patients with AOC and long-lasting fever, who became afebrile after systemic antifungal therapy. It is concluded that AOC is associated with long-lasting fever and decreased bone marrow function as judged by low thrombocyte counts, but not related to specific bacteria in the oral cavity or to an increased occurrence of C. albicans antibodies in the serum.

Risk factors for nosocomial candidemia: a case-control study in adults without leukemia

PURPOSE

The purpose of this study was to define risk factors for nosocomial candidemia in adult patients without leukemia at a tertiary care medical center.

PATIENTS AND METHODS

All patients with nosocomial candidemia between August 1, 1981, and October 31, 1984, were included if they met strict selection criteria and did not have acute or chronic leukemia. For each case, one control was selected from among patients admitted during the same month/year and matched for hospital service and duration of hospitalization up to the first blood culture that grew Candida species. Logistic regression was used to obtain estimates of risk after simultaneously controlling for other variables.

RESULTS

Candida albicans caused 24 of the 48 fungemias studied. The risk factors identified included the presence of a central line (odds ratio, 26.4; 95% confidence interval, 1.5 to 451.1); bladder catheter (13.0 1.3 to 131.4); two or more antibiotics (25.1, 2.1 to 318); azotemia (22.1, 2.2 to 223.2); transfer from another hospital (21.3, 1.7 to 274.5); diarrhea (10.2, 1.03 to 101.4); and candiduria (27.0, 1.7 to 423.5). A prior surgical procedure was associated with lowered risk (0.1, 0.01 to 0.9), suggesting perhaps that medical service patients are at higher risk than those on surgical services. Because total parenteral nutrition was always administered by means of a central line, it could not be shown to increase the risk over that conferred by a central line alone.

CONCLUSIONS

This study has defined seven major risk factors for nosocomial candidemia. These findings should facilitate development of rational approaches to preventing infection and may assist clinicians in identifying those patients in whom this life-threatening complication is likely to occur.

Fungal infections during neutropenia: the role of prophylaxis

Fungal infections are seen predominantly in patients with neoplastic diseases. Autopsy studies revealed that 30 to 50% of decreased patients with hematologic neoplasms have histopathologically documented invasive fungal infections. The rationale for fungal chemoprophylaxis is the high incidence of fungal disease in these patients (5), the high mortality (29), the difficulty in diagnosing (28), and the severe side effects of systemic antifungal therapy with amphotericin B (3). Endogenous sources such as oropharyngeal and digestive mucous membranes and exogenous pathways such as air (e.g.aspergilli) or food have to be considered. Therefore, prophylaxis has to comprise both aspects:Prevention of acquisition through nonspecific hygiene measures (5), reduction of colonization (non-absorbable antifungals or systemic chemoprophylaxis) (20). Antifungal prophylaxis of candidosis with both non- and absorbable drugs has not been convincing in terms of reduction of proven fungal infections. Prevention of aspergillosis consists mainly of the control of room air.

Comparison of immunosuppressive effects of cyclosporine A in a murine model of systemic candidiasis and of localized thrushlike lesions

Candida albicans is an opportunistic human pathogen preferentially causing invasive and disseminated infection in patients with defective phagocytic defenses and serious mucocutaneous infection in patients with deficient T-cell function. Phagocytes appear to protect the host from fungal invasion even in the absence of adaptive immune mechanisms, while as-yet-undefined T-cell-dependent factors seem necessary for control of C. albicans on body surfaces. To study host defense mechanisms on body surfaces, we developed a new model of thrush in artificial pneumatized cysts in mice. Cyclosporine A, a relative selective suppressor of T-cell-mediated immunity and natural killer cell activity, promoted the formation of thrushlike lesions on cyst surfaces and impeded elimination of C. albicans from such lesions. As expected from the absence of an impairment of antimicrobial phagocytic activity, cyclosporine A had no effect on systemic candidiasis induced by intravenous inoculation. Surprisingly, athymic nude mice were not more susceptible to superficial candidiasis than control mice and were comparably affected by cyclosporine A. In contrast, beige mice, which in addition to phagocytic dysfunction have reduced natural killer cell activity, were more susceptible to thrushlike lesions, and cyclosporine A was correspondingly less active in this mouse strain. Immunosuppression with cyclosporine A affects host defense mechanisms which are operative against superficial candidiasis but appear superfluous in resistance to the invasive form of this mycosis, an indication for the divergent nature of host defense against the two forms of candidiasis.

Experimental basis for the clinical epidemiology of fungal infections. A review

Based on the concept that the agents of deep fungal infections can be divided into primary pathogens and opportunists the experimental basis for the clinical epidemiology of mycoses is outlined. Kinetics of experimental infections with opportunists and primary pathogens discriminate between the two fungal categories. Natural resistance eliminates opportunists and prevents the establishment of progressive infection in the normal host. Primary pathogens call upon mechanisms of adoptive cell mediated immunity for their control. Therefore athymic mice which are not more susceptible to opportunists than control mice, cannot control infection with primary pathogens. In order to induce comparable overwhelming opportunistic mycoses with reasonable challenge doses, non-specific phagocytic resistance has to be eliminated. In agreement with in vivo studies, in vitro studies of the susceptibility of fungi to killing by phagocytes point out, that the susceptibility of the tissue phase of fungi to killing by "immunologically unarmed" phagocytes discriminates between opportunists and primary pathogens. In order to restrain primary pathogenic fungi, phagocytes have also in vitro to call upon adoptive, T cell-dependent immune mechanisms, which appear superfluous for control of opportunists. This difference explains the discrepant opportunistic proclivities of the two fungal categories. Patients with defective phagocytic defenses are prone to opportunistic mycoses, while deficient cell mediated immunity results in a greater vulnerability to primary pathogens.

Infantile endogenous Candida endophthalmitis presenting as a cataract

The most common pathogen to cause endogenous endophthalmitis is the fungus Candida albicans. Most cases involve adults who are either immunosuppressed or have a history of repeated or prolonged extracorporeal access to their circulatory system. Endogenous Candida endophthalmitis can occur in infants as well, particularly when prematurity, broad spectrum antibiotic therapy, or prior surgery are present as predisposing factors. We report the clinical and histopathological findings of an infant who developed a unilateral, sectoral lens opacity four months after undergoing treatment for disseminated candidiasis. The diagnosis of localized intralenticular fungal abscess with associated endophthalmitis was made via histopathologic examination of the aspirated lens material. Treatment with systemic antifungal agents successfully preserved the eye. In addition, we review and summarize the previously reported cases of Candida endophthalmitis in patients under one year of age.

Therapeutic evaluation of free and liposome-encapsulated amphotericin B in the treatment of systemic candidiasis in mice

Various doses of amphotericin B encapsulated into unilamellar vesicles of 0.1 micron diameter (lip-AMB) (1.0 to 20.0 mg/kg of body weight) were compared with free amphotericin B (AMB) (0.5 to 2.0 mg/kg of body weight) in a murine model of disseminated candidiasis. CD2F1 mice injected intravenously with 3 x 10(5) Candida albicans cells were treated with either single- or multiple-dose regimens. Untreated infected mice had a median survival of 7 days, with all mice dead by 12 days. Single doses of AMB resulted in a median survival range from 18 to 23.5 days, with less than or equal to 38% survival by day 42. Single doses of lip-AMB resulted in 88 to 100% survival by day 42. The multiple-dose AMB regimen provided median survival of only 30 to 33 days, with less than or equal to 38% survival by day 42. The multiple-dose lip-AMB regimen resulted in greater than 90% survival by day 42. With single-dose regimens, lip-AMB levels in plasma were severalfold higher than AMB levels in plasma. By 10 h, at equivalent doses, lip-AMB levels in plasma were much higher, whereas AMB levels in plasma were not detectable. Compared with normal values, the blood urea nitrogen, serum glutamic pyruvic transaminase, serum glutamic oxaloacetate transaminase, and serum lactate dehydrogenase levels were not significantly altered by high doses of lip-AMB treatment. Viable C. albicans was recoverable from the kidneys of some of the lip-AMB-treated mice at day 42. Thus, encapsulation into unilamellar liposomes enhances the antifungal efficacy of amphotericin B while reducing the toxicity normally associated with administration of free amphotericin B.

A new experimental model of localized candidosis for the study of antifungal chemotherapy

A mouse model of localized candidosis in air-filled subcutaneous cysts imitating thrush has been developed and was used to test the efficacy of various antifungal drugs. The results were similar regardless whether cortisone or cyclophosphamide was used for immunosuppression. The highest efficacy was shown by amphotericin B in relatively high doses (2 mg/kg s.c.). The new triazole derivatives also showed good chemotherapeutic activity (fluconazole, ICI 195, 739, SDZ 89-485). Flucytosine was also highly effective despite its short half-life. The model thus gives a valuable indication of the chemotherapeutic efficacy against Candida thrush in humans.

Pharmacokinetics and tissue penetration of fluconazole in rabbits

Fluconazole is a new bis-triazole antifungal compound which has in vivo and in vitro activity against Candida spp. and Cryptococcus neoformans and excellent penetration into cerebrospinal fluid. However, little is known about the penetration of fluconazole into tissue sites other than cerebrospinal fluid. We therefore studied by high-pressure liquid chromatography the penetration of fluconazole into nine different tissue sites at times of peak and trough concentrations in plasma in rabbits. Fluconazole penetrated into all tissue sites. Tissue/plasma concentration ratios were greater at time of trough concentrations in plasma than at times of peak concentrations in plasma. The finding that fluconazole penetrated into target organs commonly infected by Candida spp. and C. neoformans further supports the therapeutic potential of fluconazole for disseminated candidiasis or cryptococcosis in immunocompromised hosts.

Candida cell wall mannan: a polysaccharide with diverse immunologic properties

It is clear that mannan has the potential to influence multiple biologic functions in vivo and in vitro, including both mannan-specific and mannan-nonspecific activities. Based on in vitro studies, various mechanisms have been proposed for the regulatory activities observed, ranging from interference with normal PMNL and monocyte function to the induction of T suppressor cells. It may well be, in fact, that different mechanisms function at different levels depending upon the specific phenomenon being influenced. Approaches to determining the mechanisms involved in these regulatory phenomena, however, have been complicated by the fact that many studies were performed with mannan extracted in the laboratory by traditional methods and used as such without further purification. Most laboratory-acquired mannans appear to be heterogeneous mixtures containing polymers of differing size and charge. When such mixtures have been separated on the basis of size or charge, it has been shown that biologic function can be correlated with individual fractions, and that a single bulk preparation of mannan can contain components with opposing biologic activities. Resolution of the specific mechanisms involved in the regulatory phenomena described, therefore, will not be complete until homogeneous preparations of mannan are employed to investigate the mechanisms.

Effect of attachment of anticandidal antibody to the surfaces of liposomes encapsulating amphotericin B in the treatment of murine candidiasis

The effect produced by antibody specific to Candida albicans when attached to liposomes containing amphotericin B was studied in vivo. Liposomal amphotericin B bearing specific immunoglobulin (LAMB-Ab) was compared with the unencapsulated drug (fAMB) and other liposomal amphotericin B formulations in the short-term survival (21 days) of mice with disseminated candidiasis. Both the treatment and prophylaxis of the murine model of candidiasis were explored in these trials. LAMB-Ab increased survival rates in the model more than other liposomal preparations containing amphotericin B. Liposomal amphotericin B compounds as a group prolonged survival over fAMB. Liposomal preparations used for comparison included liposomes with attached nonspecific antibody (LAMB-Ab-), liposomes without antibody (LAMB), and liposomes with unattached specific antibody (LAMB+).

Yeasts in blood cultures: impact of early therapy

Patients with growth of yeast in blood cultures were analyzed during the 6-year-period 1981-1986, with special regard to predisposing factors, mortality, severity of the disease and therapy. There were 80 isolations of yeasts in blood cultures in 39 patients and Candida albicans was the most common. The majority of the patients in the material had multiple predisposing factors. The overall mortality was 58%. Patients with d disseminated disease had a mortality of 79% in contrast to 32% in patients with transient fungemia. Disseminated disease was more common in surgical patients. The prognosis of patients treated within 4 days from the onset of septic symptoms was significantly better than that of patients with a later start of therapy. On the basis of these results we emphasize the importance of early empiric therapy.

Surveillance tests for the diagnosis of invasive fungal infections in bone marrow transplant recipients

A system for serial surveillance cultures and serological tests for diagnosis of disseminated fungal infections (FI) was evaluated retrospectively in 14 bone marrow transplantation (BMT) patients with autopsy proven FI (11 with Candida albicans and 3 with Aspergillus fumigatus) and 14 control BMT patients without FI. The 2 groups did not differ with regard to clinical features. Serial cultures for candida from various sites were more often positive in the FI group than in the controls (p less than 0.001). Consistently negative cultures were never seen in the FI patients (p less than 0.05). Positive conventional blood cultures or cultures of specimens from bronchoscopy were suggestive of FI before death in 6/14 of the patients with FI. No blood cultures were positive among the controls. Sequential serum samples taken before death in 7 patients with systemic candidiasis, 3 with invasive aspergillosis, and 12 control patients, were tested retrospectively for diagnostic candida and aspergillus antibody titers and free circulating candida mannan. The serological tests gave evidence of FI in 9/10 patients with FI and in half of the controls (p less than 0.05). In 8/10 cases with FI, serological tests became positive before a positive blood culture or a clinical suspicion of FI. With a prevalence of 7.5% of FI at our clinic, the predictive values for positive and negative was 100% and 97% for the antigenemia test and 14% and 100% for the ELISA test for IgA antibody against C. albicans mannan. Our data suggest that a rational use of surveillance cultures and serological tests may aid in an earlier diagnosis of FI in BMT patients.

Fungal infections of the immunocompromised host: clinical and laboratory aspects

Fungal infections of the immunocompromised host are being seen with greater frequency than ever before. In addition, a growing list of unusual and unexpected etiologic agents presents a unique and difficult challenge to the clinician and microbiologist. The clinical manifestations of opportunistic fungal infections are often not characteristic and, in many instances, may prevent a rapid diagnosis from being made. Clinical microbiology laboratories should consider any organism as a potential etiologic agent. This requires that all fungi recovered from immunocompromised patients be thoroughly identified and reported so that their clinical significance may be assessed. This review presents a brief discussion of the clinical and laboratory aspects of some fungal infections seen in this important group of patients.

Infectious complications in childhood acute leukemias

Infectious complications in children with acute leukemias are reviewed as to incidence, predisposing factors, microbiologic etiologies and treatment. Principles of antimicrobiologic therapy are presented for bacterial, fungal, viral, and protozoal infections seen in children with cancer. Prevention of infection is also discussed.

Esophageal candidiasis. Managing an increasingly prevalent infection

Esophageal candidiasis is an opportunistic infection that is being recognized increasingly often in certain patients, including those who have a neoplastic disease, are undergoing protracted antibiotic therapy, or hae acquired immunodeficiency syndrome (AIDS). Impaired cell-mediated immunity may predispose the patient to esophageal mucosal colonization, whereas chemotherapy-induced granulocytopenia may predispose to disseminated candidiasis. Esophageal candidiasis should be suspected in susceptible patients with complaints of substernal odynophagia or dysphagia. The diagnosis is confirmed by endoscopically directed mucosal biopsy. Esophagitis from other causes (eg. herpes simplex virus, cytomegalovirus, or bacterial infection) may develop concomitantly with esophageal candidiasis. Treatment is determined by the clinical and immune status of the patient. Amphotericin B (Fungizone) is administered to immunocompromised patients at risk for disseminated or deeply invasive candidiasis and is indicated in nongranulocytopenic patients whose symptoms prevent reliable administration of oral antifungal agents. Ketoconazole (Nizoral) may be administered to clinically stable nongranulocytopenic patients with esophageal candidiasis limited to the mucosa. Patients with AIDS and a history of esophageal candidiasis usually benefit from long-term suppression with an oral antifungal agent.

Chronic muco-cutaneous candidiasis and oral neoplasia

Two patients with chronic muco-cutaneous candidiasis who subsequently developed oral neoplasia are presented. In both cases the tumours appeared in the fourth decade of life. The natural history of these tumours was not unique but varied from the norm. In one patient there was an obvious propensity for metastasis; in the other, three separate tumours evolved. An argument could be made to link the unusual features evident in these two cases with the state of altered immunity known to occur in chronic muco-cutaneous candidiasis, although the suggestion is speculative.

Development of DNA probes for Candida albicans

An attempt was made to produce DNA probes that could be used as a rapid and efficient means of detecting candidiasis (invasive Candida infection) in immunocompromised patients. Whole DNA from Candida albicans was digested with restriction endonuclease, and the resulting fragments were randomly cloned into a plasmid vector. Several recombinant plasmids were evaluated for cross-hybridization to various other Candida species, other fungal DNAs, and to nonfungal DNAs. Cross reactions were observed between the probes and different yeasts, but none with unrelated DNAs. Some recombinants were genus-specific, and two of these were applied to the analysis of C. albicans growth curves. It became evident that, although both 32P- and biotin-labelled probes could be made quite sensitive, a possible limitation in their diagnostic potential was the poor liberation of Candida DNA from cells. Thus, better methods of treatment of clinical specimens will be required before such probes will be useful in routine diagnosis.

Detection of Candida sp. mannan antigen by indirect ELISA-inhibition. In vitro crossed reactivity among mannans obtained from C. albicans A, C. albicans B, and C. tropicalis

We have obtained mannans from four Candida species: C. albicans A, C. albicans B and C. tropicalis; anti-mannan sera against C. albicans A, C. albicans B and C. tropicalis were obtained by immunizing rabbits subcutaneously with the respective yeast extract. The efficacy of these sera in reacting with mannans obtained from three Candida sp. has been proven by indirect ELISA-inhibition. Any of three immune sera can be used to detect mannan antigen from the three Candida sp. tested. This confirms the existence of crossed reactivity and the possibility of detecting mannan antigen in serum from patients infected by different Candida sp., although we had only one immune serum and one Candida mannan.

The relationship of oral Candida tropicalis infection to systemic candidiasis in a patient with leukemia

Oropharyngeal candidiasis is an extremely common complication in patients receiving chemotherapy for leukemia. Candida tropicalis appears to be the major infectious agent when these patients develop candidemia. In this article, a case of C tropicalis fungemia with oropharyngeal manifestations is presented. The relationship of oropharyngeal candidiasis to oral candidal infection is discussed.

A Candida albicans dispersed, repeated gene family and its epidemiologic applications

Candida albicans causes a wide variety of infections but can readily be isolated from the skin and mucosa of healthy individuals. To enable high-resolution epidemiologic studies on this common pathogen, a species-specific DNA probe has been isolated from its genome. There are approximately equal to 10 copies of the sequence dispersed among the chromosome-sized DNA molecules resolved by pulsed-field electrophoresis. New DNA polymorphisms in this gene family arise at high rates. As a consequence, this probe will readily distinguish strains from different patients in the same hospital and from various sites in individual patients. The DNA polymorphisms detected by using this probe are largely due to internal changes in members of the family rather than movement to new genomic locations. This suggests recombination or gene conversion rather than transposition as the mechanism producing the observed variation.

Comparison of antibody, antigen, and metabolite assays in rat models of systemic and gastrointestinal candidiasis

We compared serial measurements of antibodies to mannan and to a cytoplasmic antigen (enzyme-linked immunosorbent assays), detection of mannan and an unidentified candidal antigen (latex agglutination), and assays of mannose and arabinitol (gas chromatographic assay of per-O-acetylated aldonitrile derivatives). In a high-inoculum intravascular-infection model, antimannan assays were consistently positive beginning on day 2 postinoculation, anti-cytoplasmic antigen assays followed the same time course but were less sensitive, mannan was detected in all samples beginning on day 2 postinoculation, and serum mannose concentrations peaked on day 3 postinoculation and were less sensitive than mannan detection. Other assays were not useful. In a lower-inoculum intravascular-infection model, the antibody assays became positive after a similar interval and remained positive for 28 days, with antimannan again being the more sensitive. Mannan and mannose tests were positive in week 1 postinoculation only, with mannan detection being the more sensitive. In a gastrointestinal-colonization model, antimannan assays become positive after 2 weeks of colonization, whereas anti-cytoplasmic antigen and mannan tests remained negative. In a model of gastrointestinal colonization followed by invasive infection produced by induction of neutropenia, only mannan detection was diagnostically useful. These data, comparing this panel of modern serodiagnostic techniques in controlled models of clinically relevant syndromes of candidiasis, enhance understanding of previous efforts in serodiagnosis of candidiasis and provide a foundation for further prospective studies in patients.

Juvenile juxtavermilion candidiasis: yet another form of an old disease?

Five cases of a chronic, self-limiting Candida albicans infection of the lip vermilion and juxtavermilion skin in young persons are presented. These infections typically appeared as erythematous, pruritic, yellow crusting plaques of the juxtavermilion skin, with or without desquamation of vermilion surfaces. Evidence of intraoral candidiasis, especially loss of filiform lingual papillae, was present in several cases. The disorder mimics the early stage of chronic mucocutaneous candidiasis but remains within a few millimeters of the mucocutaneous junction and affected individuals appear (with a possible exception) to be immune competent. Mild trauma apparently triggers the infection. The authors emphasize that a scientifically sound cause-and-effect relationship between this new disease and Candida albicans is not herein established and present these cases in the hope that others will thereby be identified and a firmer causal relationship be established.

Toxicity and therapeutic effects in mice of liposome-encapsulated nystatin for systemic fungal infections

The therapeutic activity of nystatin (NYS) incorporated in multilamellar liposomes (L-NYS) was studied in vivo. Hale-Stoner mice injected intravenously with various doses of L-NYS and free NYS showed a significant reduction in toxicity of NYS after the NYS was incorporated into liposomes (maximal tolerated doses, 16 and 4 mg/kg of body weight, respectively). The maximal tolerated dose of free NYS had no effect in the treatment of mice infected with Candida albicans, whereas L-NYS at an equivalent dose improved the survival of mice. A marked increase in survival was observed when L-NYS was administered in higher and multiple doses (total doses up to 80 mg/kg). Liposome encapsulation thus provided a means for intravenous administration of NYS, reducing its toxicity and making it an active systemic antifungal agent.

Diagnosis of invasive candidiasis in patients with and without signs of immune deficiency: a comparison of six detection methods in human serum

Visceral candidiasis in 56 patients, 39 of whom were thought to be immune deficient, was investigated using three serological detection methods--whole cell agglutination, haemagglutination, and counterimmunoelectrophoresis for antibodies; two determinations of circulating antigens--haemagglutination inhibition and latex agglutination; and determination of the arabinitol:creatinine ratio. Of the 39 patients with suspected immune deficiency, 13 had confirmed invasive candidiasis and 26 were colonised; of those without signs of immune deficiency, 10 patients also had invasive candidiasis and seven were colonised. Twenty three patients with invasive candidiasis were analysed in total. For suspected immune deficient patients the best discrimination between visceral candidiasis and colonisation was obtained by combining the results of haemagglutination inhibition and arabinitol:creatinine ratio. For patients without signs of immune deficiency the best discrimination between invasive candidiasis and colonisation was achieved with counterimmunoelectrophoresis. The results of the serological tests confirmed the classification on clinical grounds of those with and without immune deficiency.

Liposomes in treatment of infectious diseases

In reviewing the literature about the potential of liposomes in the therapy of infections caused by protozoa, bacteria, fungi and viruses, it can be concluded that liposomal encapsulation may improve the therapeutic index of anti-infectious drugs. The improved therapeutic index may be a result of a reduction in drug toxicity and/or an enhanced drug delivery at the intracellular site of infection. Furthermore, attention is paid to the therapeutic utility of liposome-encapsulated immunomodulators in treatment of infections.

Systemic candidiasis in heroin abusers. Cutaneous findings

Systemic candidiasis in intravenous drug abusers (IVDA) is a new syndrome caused by Candida albicans and characterized by the sequential development of skin, eye, and osteoarticular lesions, which together form a typical clinical picture. We studied 30 patients with suggestive skin lesions: papules, nodules, and pustules in hair-bearing areas, particularly the scalp and beard area, associated with hair invasion by candidal hyphae. Ocular and osteoarticular involvement and presence of candidemia in some of the patients suggested blood-borne colonization of C. albicans. The infection has been related to "brown" heroin. The origin of C. albicans and the reasons for its exclusive localization in the skin and these organs are discussed. The characteristic clinical picture is widely different from that of classic disseminated candidiasis in immunodeficient patients. Therapy is also discussed.

Candida osteomyelitis. Report of five cases and review of the literature

Candida species have emerged as important pathogens in human infection. Although a variety of deep-seated candidal infections have been reported, Candida osteomyelitis has rarely been described. Five patients with Candida osteomyelitis are presented, and the 32 adult cases previously reported are reviewed. Candida osteomyelitis is noted as a simultaneous occurrence or late manifestation of hematogenously disseminated candidiasis. Osteomyelitis may not be prevented by a course of amphotericin B adequate to control the acute episode of disseminated candidiasis, particularly in immunosuppressed patients. Less commonly, Candida osteomyelitis presents as a postoperative wound infection. Like bacterial osteomyelitis, the most common presenting symptom is local pain. The insidious progression of infection, the nonspecificity of laboratory data, and the failure to recognize Candida as a potential pathogen may lead to diagnostic delay. Diagnosis can be made by either open biopsy or closed needle aspiration. Successful therapeutic regimens have employed combinations of antifungal therapy (most often amphotericin B) with surgical debridement when indicated. It is anticipated that osteomyelitis will become a more commonly recognized manifestation of hematogenously disseminated candidiasis.

Candidacidal factors in murine bronchoalveolar lavage fluid

Respiratory secretions provide an efficient method for protecting the large surface area of the lower respiratory tract. To determine whether lung secretions contribute to antifungal defenses, we tested bronchoalveolar lavage fluid for fungicidal activity. Candida albicans (blastoconidia) was incubated in unconcentrated cell-free lavage fluid from Swiss Webster mice and then cultured quantitatively to measure residual viability. In control buffer the residual fractions of viable fungi were 1.03 +/- 0.12 at 60 min and 0.84 +/- 0.05 at 120 min, whereas the residual fractions in lavage fluid were 0.64 +/- 0.07 and 0.23 +/- 0.05, respectively (P less than 0.05 by t tests). This activity was trypsin sensitive and heat stable (56 degrees C) and did not require divalent cations. It did not sediment with the surfactant fraction of lung lavage fluid. Unconcentrated lavage fluid reduced the adherence of C. albicans to serum-coated glass tubes to 2.3 +/- 1.5% of that of control Candida suspensions (n = 5, P less than 0.05 by t test). It did not alter Candida ingestion or intracellular processing by alveolar macrophages. Lavage fluid also killed clinical isolates of Candida tropicalis and Torulopsis glabrata but did not kill Candida krusei or Candida parapsilosis. Lavage fluid was concentrated and passed through an acrylamide-agarose gel matrix. The chromatogram indicated that the candidacidal activity eluted in a peak with a molecular weight range of 29,000 to 40,000. After electrophoresis on 15% sodium dodecyl sulfate-polyacrylamide gels, these fractions resolved into three bands. These were transferred to nitrocellulose and then eluted with Triton X-100; this procedure permitted the isolation of a single band of candidacidal activity with a molecular weight of 29,000. In summary, murine lavage fluid contains a heat-stable protein with direct antifungal activity. This soluble factor may contribute to lung defense processes by reducing fungal viability and adherence to tissue surfaces.

Heterogeneous activity of immature and mature cells of the murine monocyte-macrophage lineage derived from different anatomical districts against yeast-phase Candida albicans

Mature mononuclear phagocytes have been receiving much attention as effectors of spontaneous candidacidal activity, although with controversial results due to differences in the effector populations and the methods used in different laboratories. We here systematically compare the fungistatic activity of immature and mature cells of the murine macrophage series. The results show that nonadherent, nonphagocytic precursor cells (isolated either [90% purity] from bone marrow liquid cultures or from the organs of mice in which inflammatory conditions had been elicited in vivo) exerted a strong extracellular candidastatic activity. In contrast, mature macrophages, either obtained from different anatomical areas (spleen, liver, lung, peritoneal cavity) or matured in vitro from the precursor populations, displayed striking heterogeneity in their ability to inhibit the growth of Candida albicans, depending on the anatomical site they were derived from. Lymphokine activation did not alter the fungistatic pattern of the untreated cells. The different macrophage populations behaved very differently also in the production of reactive oxygen intermediates (ROI) in response to phagocytosis of C. albicans. The amounts of ROI generated, however, showed no correlation with candidastatic ability. Low levels of candidastatic activity exerted by resident peritoneal macrophages (good ROI producers) were inhibited by catalase, whereas high levels of growth inhibition by Kupffer cells (poor ROI producers) after 8 h of assay were hardly influenced by the enzyme. Our data suggest the existence of two different effector mechanisms in macrophage-mediated C. albicans growth inhibition, a rather inefficient ROI-dependent one, and a second, very efficient oxygen-independent mechanism. The implications of these findings are discussed.

Microtiter broth dilution method for yeast susceptibility testing with validation by clinical outcome

There is no ideal laboratory procedure or culture medium in current use for susceptibility testing of pathogenic yeasts. Six candidate growth media (RPMI 1640 with L-glutamine, yeast nitrogen base, Casamino Acids medium, Mueller-Hinton broth, Sabouraud dextrose broth, and minimum essential medium-Eagle salts) were screened by spectrophotometric absorbance for nucleic acid and protein. From these, two media were selected: a chemically defined growth medium (RPMI 1640 with L-glutamine) and a chemically complex medium (Casamino Acids). MICs of four antifungal agents (5-fluorocytosine, miconazole, ketoconazole, and amphotericin B) for 84 clinical isolates of various Candida species were then determined with both media in agar dilution and microtiter broth dilution systems. The resultant MICs were correlated with clinical outcome for those isolates obtained from patients treated with single antifungal agents, and susceptibility cut points were calculated. Derived MIC cut points for susceptibility were validated in a murine model of systemic candidiasis. RPMI 1640 with L-glutamine was found to have the lowest absorbance values for both nucleic acid and protein, while Casamino Acids medium was highest in both categories. We found that RPMI 1640 with L-glutamine was superior to Casamino Acids medium in the yield of MICs which correlated with actual clinical and animal outcome data. While there were no significant differences in MICs when RPMI 1640 medium was used, the microtiter broth dilution technique was superior to agar dilution in efficiency and ease of performance. We conclude that a microtiter broth system containing RPMI 1640 medium with L-glutamine is a simple, precise, and economical technique for susceptibility testing of pathogenic Candida species. We also suggest that the validation of susceptibility cut points with patient and animal outcome data make this microtiter broth system a preferential method for yeast susceptibility testing.

Candida detection system (CAND-TEC) to differentiate between Candida albicans colonization and disease

Eighty-three serum specimens from 24 patients infected with Candida albicans were examined for circulating Candida protein antigens with the Candida Detection System (CAND-TEC; Ramco Laboratories, Inc., Houston, Tex.). The medical records of each patient were reviewed for clinical evidence of Candida colonization or disease, predisposing factors for infection, underlying illness, the presence of a contaminated indwelling venous catheter, intravenous amphotericin B therapy, and outcome. Forty-nine serum specimens with antigen titers of 1:2 or less were obtained either from colonized patients or at a time when disseminated disease was not yet clinically suspected. Except for five specimens from two colonized patients, one with a contaminated arterial line, the other specimens with titers of 1:8 or greater (n = 14) were obtained from patients who had been clinically diagnosed and treated for disseminated candidiasis. Serum specimens with titers of 1:4 were often from patients with deep-seated candidal infection but were not uniformly diagnostic; in this situation additional specimens should be tested for Candida antigen titers. Only 1 of 24 serum specimens from patients with no evidence of C. albicans infection had a Candida protein antigen titer of 1:8. With a 1:8 or greater titer as a criterion for dissemination, the sensitivity of the CAND-TEC system was 71%, with a specificity of 98%. If the 1:8 titer for the colonized patient with a contaminated arterial line is not considered a false-positive result, the CAND-TEC sensitivity was 83%. The latex agglutination assay appears to be a useful, rapid, and noninvasive means of laboratory diagnosis of systemic candidiasis. The recovery of C. albicans from at least three body sites may also be a useful predictor of disseminated disease.

Activity of compound G2 isolated from alfalfa roots against medically important yeasts

An antimycotic agent was isolated from roots of alfalfa and further purified to yield a nonhemolytic, homogeneous compound (G2). This compound contained considerable activity against 10 medically important yeasts. MICs obtained by both agar and broth dilution methods ranged from 3 to 15 micrograms/ml. Compound G2 was fungicidal at a relatively low concentration for nine different species of yeasts tested (minimum fungicidal concentrations ranged between 6 and 24 micrograms/ml). The considerable stability of compound G2 and its strong inhibitory and fungicidal activity against a broad range of yeasts suggest that after further development it might be useful as an active agent in the treatment of mycotic infections.

In vitro susceptibility of fungi to killing by neutrophil granulocytes discriminates between primary pathogenicity and opportunism

Pathogenic fungi, according to their propensity to cause infection of apparently normal individuals, can be grouped into either primary pathogens (e.g., Coccidioides, Histoplasma, Paracoccidioides, Blastomyces, and Sporothrix) or opportunists (e.g., Candida, Mucoraceae, Aspergillus spp., Petriellidium, and Trichosporon). There is, however, no unifying concept explaining the difference between the virulence of the two fungal categories. Previously we have speculated that neutrophils are the common denominator of the high natural resistance to opportunistic fungi. Accordingly, we then compared the susceptibility to killing by neutrophil granulocytes of Histoplasma, Blastomyces, Paracoccidioides, and Sporothrix with that of 14 opportunistic fungi. We found the four virulent dimorphic yeasts, in contrast to opportunistic fungi, to be resistant to killing by neutrophils. Virulent dimorphic yeasts were ingested by neutrophils, and triggered a respiratory burst comparably to opportunists but were less susceptible to hydrogen peroxide, suggesting that differences in the susceptibility to microbicidal products of leukocytes may explain the difference in virulence.

Simple new test for presumptive differentiation between genus Candida and genus Prototheca

A differential test was made between genus Candida and genus Prototheca using a new and very simple differential test. A total of 59 strains of Candida and 78 strains of Prototheca were used. The basis of the test was the differential use of a disc carrying 60 mcg of Ribostamycin to which all the Candida were resistant and the Prototheca inhibited.

Candidal suppurative peripheral thrombophlebitis: recognition, prevention, and management

Candida species are seldom considered as a cause of suppurative peripheral thrombophlebitis. During a 15-month period in a 291-bed acute-care hospital, candidal suppurative peripheral thrombophlebitis developed in seven patients. All patients had fever, a tender palpable cord, and Candida species isolated from resected veins and/or pus expressed at the catheter entrance site. Four patients had candidemia. None were neutropenic or recipients of corticosteroids. All had concomitant or preceding bacterial infections, and had received a median of 5 antibiotics (range 3 to 9) for at least 2 weeks. Five of seven had documented preceding candidal colonization associated with broad spectrum antibiotic therapy. Catheter sites had not been routinely rotated and local catheter site care was deficient. Risk factors of antibiotics and duration of hospitalization were fewer in patients with bacterial suppurative thrombophlebitis. Combined segmental venous resection and intravenous amphotericin B appears to be the most rational therapy for this nosocomial fungal infection.

Effects of sterols on the therapeutic efficacy of liposomal amphotericin B in murine candidiasis

Incorporation of amphotericin B (AMP-B) into phospholipid vesicles (liposomes) has been shown previously to decrease AMP-B toxicity while retaining the antifungal efficacy of the drug. In this report, the role of sterols in the formulation of liposomes as well as in their effectiveness in the treatment of murine candidiasis have been investigated. The presence of ergosterol or cholesterol at different lipid ratios did not augment the encapsulation efficiency of AMP-B as compared with vesicles containing phospholipids alone. There was no significant difference in the survival time of mice infected with Candida albicans treated with sterol-containing vesicles compared with those treated with sterol-free vesicles. These findings suggest that the sterol-free liposomes might be of advantage for delivering AMP-B because of its simple formulation, lack of toxicity, and ease of preparation.

Disseminated candidiasis: a comparison of two immunologic techniques in the diagnosis

Eighty-five subjects were tested for the presence of circulating candidal antigen (CAg) and anti-candidal antibody (CAb) using both an enzyme immunoassay (ELISA) and counterimmunoelectrophoresis (CIE). The 72 studied controls included laboratory volunteers; hospitalized patients without evidence of infection; febrile hospitalized patients without evidence of candidiasis; and patients with superficial candidiasis and candiduria. The control subjects were compared with 13 patients with proven disseminated candidal infection (disease prevalence = 15%). The ELISA CAb test was of greater individual sensitivity (92%) in separating patients with systemic candidiasis from all controls combined than the ELISA CAg, CIE CAg, or CIE CAb test (61%, 15%, 69%, respectively). The CIE CAg test, though specific (100%), was insensitive. Sensitivity, specificity, and predictive values were generally enhanced by employing combinations of tests. Sera from patients with disseminated candidiasis were much more likely to yield a positive result by two or more serologic tests than were control sera (p = less than 0.0004). The sensitivity of combinations ranged from 15% to 92%. The specificity of combinations ranged from 21% to 100%. The predictive value positive of combinations test ranged from 40% to 100%. Predictive value negative of combinations ranged from 69% to 98%. Patients with a variety of superficial and deep candidal infections apparently have detectable circulating CAb and/or CAg. The ELISA CAb test was superior to the other tests in identifying patients with disseminated candidiasis. Combinations of serologic tests may be superior to individual tests in the diagnosis or exclusion of serious disease due to Candida albicans.

In-vitro killing of Candida species by murine immunoeffectors and its relationship to the experimental pathogenicity

Killing of yeast cells of several species of Candida by murine phagocytic cells was assessed in vitro by a radiolabel release microassay and measurement of colony forming units. The most effective candidacidal phagocytes, i.e. polymorphonuclear and bone marrow cells, were able to kill equally well cells of any species or isolate tested, given sufficient time (4 h) and an appropriate effector: target ratio. However, C. guilliermondii, C. krusei and C. parapsilosis were killed by polymorphonuclear and bone marrow cells much more promptly (1 h) and at a significantly lower effector:target ratio than C. albicans, C. tropicalis and C. viswanathii. Moreover, there were immune effectors such as peritoneal resident macrophages and, mostly, spleen cells which were practically ineffective against C. albicans and C. tropicalis but showed significant activity against C. guilliermondii, C. krusei and C. parapsilosis, even in mice immuno-depressed with cyclophosphamide. Three isolates of C. albicans, differing in the capacity to form germ tubes, also differed in mouse virulence: the germ-tube forming isolate was the most virulent. However, they showed an identical pattern of susceptibility to killing by mouse immunoeffectors, suggesting that virulence is probably not due to the resistance of hyphal cell to phagocytosis.