Skin colonization by Malassezia in neonates and infants.

OBJECTIVE: To identify the timing, pattern, and determinants of colonization of neonates by Malassezia. DESIGN: Prospective observational study. SETTING: A neonatal medical and surgical unit consisting of 10 special care, 10 high-dependency, 10 intensive care, and 10 surgical cots. PARTICIPANTS: All neonates (< or = 28 days of age) or infants (> 28 days of age) admitted to the unit during the 20-week period from October 1995 to March 1996. METHODS: All infants or neonates were swabbed on the day of admission and every third day thereafter and risk factors were collected for every day on the unit. RESULTS: During the study period, 245 neonates and 42 infants were sampled for their entire duration of stay on the unit. Of these, 41 infants (97.6%) were colonized with Malassezia on admission to the unit and thereafter, as assessed by subsequent samples. Within the neonate population, 78 (31.8%) became colonized, but none were colonized immediately after birth. Univariate analysis showed that many factors appeared to be significantly associated with colonization in the neonates, including use of ventilation, presence of central venous catheters, use of parenteral nutrition, and use of antibacterial or antifungal drugs. However, when the data were analyzed by multivariate logistic regression to control for confounding variables, only gestational age and length of stay on the unit were found to be significantly associated with colonization. CONCLUSION: Colonization of infants is not as unusual as previously thought and many infants have established a cutaneous Malassezia commensal flora by the age of 3 to 6 months. Factors that predispose to colonization in neonates may not be the same as those that predispose to infection.

A systematic review of the antifungal effectiveness and tolerability of amphotericin B formulations.

OBJECTIVE: A systematic review was performed to compare the effectiveness and tolerability of lipid-based amphotericin B (AmB) formulations and conventional AmB in the treatment of systemic fungal infections. METHODS: The literature and unpublished studies were searched using MEDLINE, EMBASE, Biological Abstracts, AIDSLINE, CANCERLIT, CRD database, Cochrane Controlled Trials Register, and other databases. Search terms included: amphotericin, liposom*, lipid*, colloid*, antifungal agents, and mycoses. Studies were selected according to predetermined criteria. The outcome measures reviewed were efficacy, mortality, renal toxicity, and infusion-related reactions. Meta-analyses and number-needed-to-treat (NNT) analyses were performed. RESULTS: Seven studies (8 publications) met the entry criteria. Meta-analysis showed that lipid-based formulations significantly reduced all-cause mortality risk by an estimated 28% compared with conventional AmB (odds ratio [OR], 0.72; 95% CI, 0.54 to 0.97). There was no significant difference in efficacy between the lipid-based formulations and conventional AmB (OR, 1.21; 95% CI, 0.98 to 1.49). AmB lipid complex (ABLC) and liposomal AmB (L-AmB) significantly reduced the risk of doubling serum creatinine by an estimated 58% (OR, 0.42; 95% CI, 0.33 to 0.54). There was no significant reduction in risk of infusion-related reactions with lipid-based formulations, although this was difficult to interpret given the lack of consistent control of confounding factors. Comparing the lipid-based formulations with conventional AmB, the overall NNT to prevent 1 death was 31. The NNT to prevent a doubling of serum creatinine for both ABLC and L-AmB compared with conventional AmB was 6. CONCLUSIONS: This study demonstrates advantages with lipid-based formulations over conventional AmB in terms of reduced risk of mortality and renal toxicity. Future trials in patients with proven fungal infection should control for factors such as premedication, infusion rates, fluid preloading, sodium/potassium supplementation, and concomitant medication.

Long-term effectiveness of treatment with terbinafine vs itraconazole in onychomycosis: a 5-year blinded prospective follow-up study.

OBJECTIVE: To examine long-term cure and relapse rates after treatment with continuous terbinafine and intermittent itraconazole in onychomycosis. DESIGN: Long-term prospective follow-up study. SETTING: Three centers in Iceland. SUBJECTS: The study population comprised 151 patients aged 18 to 75 years with a clinical and mycological diagnosis of dermatophyte toenail onychomycosis. INTERVENTIONS: In a double-blind, double-dummy study, patients were randomized to receive either terbinafine (250 mg/d) for 12 or 16 weeks or itraconazole (400 mg/d) for 1 week in every 4 for 12 or 16 weeks (first intervention). Patients who did not achieve clinical cure at month 18 or experienced relapse or reinfection were offered an additional course of terbinafine (second intervention). MAIN OUTCOME MEASURES: The primary efficacy criterion was mycological cure, defined as negative results on microscopy and culture at the end of follow-up and no requirement of second intervention treatment. Secondary efficacy criteria included clinical cure without second intervention treatment and mycological and clinical relapse rates. RESULTS: Median duration of follow-up was 54 months. At the end of the study, mycological cure without second intervention treatment was found in 34 (46%) of the 74 terbinafine-treated subjects and 10 (13%) of the 77 itraconazole-treated subjects (P<.001). Mycological and clinical relapse rates were significantly higher in itraconazole vs terbinafine-treated patients (53% vs 23% and 48% vs 21%, respectively). Of the 72 patients who received subsequent terbinafine treatment, 63 (88%) achieved mycological cure and 55 (76%) achieved clinical cure. CONCLUSION: In the treatment of onychomycosis, continuous terbinafine provided superior long-term mycological and clinical efficacy and lower rates of mycological and clinical relapse compared with intermittent itraconazole.

Immunology of diseases associated with Malassezia species.

Malassezia species are members of the human cutaneous commensal flora, in addition to causing a wide range of cutaneous and systemic diseases in suitably predisposed individuals. Studies examining cellular and humoral immune responses specific to Malassezia species in patients with Malassezia-associated diseases and healthy controls have generally been unable to define significant differences in their immune response. The use of varied antigenic preparations and strains from different Malassezia classifications may partly be responsible for this, although these problems can now be overcome by using techniques based on recent work defining some important antigens and also a new taxonomy for the genus. The finding that the genus Malassezia is immunomodulatory is important in understanding its ability to cause disease. Stimulation of the reticuloendothelial system and activation of the complement cascade contrasts with its ability to suppress cytokine release and downregulate phagocytic uptake and killing. The lipid-rich layer around the yeast appears to be pivotal in this alteration of phenotype. Defining the nonspecific immune response to Malassezia species and the way in which the organisms modulate it may well be the key to understanding how Malassezia species can exist as both commensals and pathogens.

Restriction fragment length polymorphism analysis of ribosomal DNA intergenic regions is useful for differentiating strains of Trichophyton mentagrophytes.

Twenty isolates of Tricophyton mentagrophytes var. mentagrophytes and 47 isolates of T. mentagrophytes var. interdigitale, identified by morphological characteristics, were screened by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). Sixty isolates (14 of 20 T. mentagrophytes var. mentagrophytes isolates and 46 of 47 T. mentagrophytes var. interdigitale isolates) shared an identical ITS RFLP profile and were further investigated by using a probe targeted to the rDNA nontranscribed spacer (NTS) region. Polymorphisms were observed in the NTS regions of both T. mentagrophytes var. mentagrophytes and T. mentagrophytes var. interdigitale isolates. Twenty-three individual RFLP patterns (DNA types P-1 to P-12 and A-1 to A-11) were recognized and divided into two groups depending on the presence (P) or absence (A) of a 2.5-kb band, which correlated to a large extent with the morphological variety. Eleven of 14 T. metagrophytes var. mentagrophytes isolates were A types, and all of the 46 T. mentagrophytes var. interdigitale isolates were P types. A majority of strains (23 of 60 [38.3%]) were characterized by one RFLP pattern (pattern P-1), and eight types (P-1 to P-6, P-8, and P-9) accounted for 75% (45 of 60) of all strains, including all of the T. mentagrophytes var. interdigitale isolates. The remaining 15 types were represented by one only isolate and included all of the T. mentagrophytes var. mentagrophytes isolates. We conclude that RFLP analysis of the rDNA NTS region is a valuable technique for differentiation of T. mentagrophytes strains. Furthermore, by use of this method, there appears to be a greater degree of diversity among T. mentagrophytes var. mentagrophytes isolates than among T. mentagrophytes var. interdigitale isolates.