Antifungal pharmacotherapy for neonatal candidiasis

Pharmacokinetics and safety of caspofungin in neonates and infants less than 3 months of age

Candida infections represent a major threat in neonatal intensive care units. This is the first prospective study to obtain caspofungin plasma levels and safety data for neonates and very young infants. Patients of <3 months of age receiving intravenous amphotericin B for documented or highly suspected candidiasis were enrolled in a single-dose (n = 6) or subsequent multiple-dose (n = 12) panel; all received caspofungin at 25 mg/m(2) once daily as a 1-hour infusion. Caspofungin plasma levels were measured by high-performance liquid chromatography and compared to historical data from adults. Patient chronological ages ranged from 1 to 11 weeks, and weights ranged from 0.68 to 3.8 kg. Gestational ages ranged from 24 to 41 weeks. Geometric mean (GM) peak (C(1 h)) and trough (C(24 h)) caspofungin levels were 8.2 and 1.8 microg/ml, respectively, on day 1, and 11.1 and 2.4 microg/ml, respectively, on day 4. GM ratios for C(1 h) and C(24 h) for neonates/infants relative to adults receiving caspofungin at 50 mg/day were 1.07 and 1.36, respectively, on day 1, and 1.18 and 1.21, respectively, on day 4. Clinical and laboratory adverse events occurred in 17 (94%) and 8 (44%) patients, respectively. Five patients (28%) had serious adverse events, none of which were considered drug related. Caspofungin at 25 mg/m(2) once daily was well tolerated in this group of neonates/infants of <3 months of age and appears to provide relatively similar plasma exposure to that obtained in adults receiving 50 mg/day. However, the small number of patients studied precludes any definitive recommendations about caspofungin dosing for this group comprising a broad range of ages and weights.

A comparison of AmBisome to amphotericin B for treatment of systemic candidiasis in very low birth weight infants

PURPOSE

Amphotericin B is considered the treatment of choice for systemic candidiasis, but adverse effects may limit its use. An alternative option for the treatment of candidiasis includes lipid preparations of amphotericin B. This study investigated the safety and efficacy of AmBisome, a lipid formulation of amphotericin B containing liposomal structures, for the treatment of systemic candidiasis in very low birth weight infants (VLBWI).

MATERIALS AND METHODS

Data from 26 VLBWI treated with AmBisome in the study group (AmBisome group) from October 2003 to July 2006 were compared with data from 20 VLBWI treated with amphotericin B as a historical control (Amphotericin group). This study was a prospective, historical control, multi-center trial.

RESULTS

Candida spp. was isolated in 73% (19/26) of the cases for the AmBisome group and 90% (18/20) of the cases for the Amphotericin group. The fungal eradication rate and the time to eradication was 84% (16/19) and 9+/-8 days in the AmBisome group, and 89% (16/18) and 10+/-9 days in the Amphotericin group, respectively (p=0.680 vs p=0.712). The major adverse effects were lower in the AmBisome group (renal toxicity, 21% vs 55%, p=0.029; hepatotoxity, 25% vs 65%, p=0.014, AmBisome group vs Amphotericin group, respectively). There was no significant difference in mortality attributed to systemic candidiasis (12% in the AmBisome group, 10% in the Amphotericin group, p=0.868).

CONCLUSION

AmBisome is effective and safe for treating systemic fungal infections in VLBWI.

The pharmacokinetics and safety of micafungin, a novel echinocandin, in premature infants

BACKGROUND

: Candidal fungal infection rates in neonates are increasing and are a significant cause of mortality, especially in low birth weight infants. Micafungin is an echinocandin that works by inhibiting 1,3-beta-D-glucan synthase, an enzyme responsible for fungal cell wall synthesis. The objective of this study was to determine the safety and pharmacokinetics of micafungin in premature infants.

METHODS

: This was a phase I, single-dose, multicenter, open-label, sequential-dose trial of intravenous micafungin investigating 3 doses (0.75 mg/kg, 1.5 mg/kg and 3.0 mg/kg) in 18 premature infants weighing >1000 g (n = 6 in each dosage group). A further 5 infants (500-1000 g) were enrolled in the 0.75 mg/kg dosage group only.

RESULTS

: The mean +/- standard deviation gestational age in the >1000 g dosage group was 26.4 +/- 2.4 weeks and, on entry, patients had one or more of a variety of underlying conditions, including sepsis, pneumonia and other infections caused by Candida or other species. Micafungin pharmacokinetics in preterm infants appears linear. However, premature infants >1000 g on average displayed a shorter half-life (8 hours) and a more rapid rate of clearance (approximately 39 mL/h per kg) compared with published data in older children and adults. All doses of micafungin were well tolerated and no serious drug-related adverse events were observed.

CONCLUSIONS

: Single doses of micafungin, ranging up to 3.0 mg/kg, appear well tolerated in premature infants weighing >1000 g. The drug's elimination half-life and total plasma clearance in preterm infants appear dissimilar to published values for these parameters in older children and adults. The reason(s) for this apparent difference remain to be investigated.

[Invasive fungal dermatitis in extremely premature newborns: a specific clinical form of systemic candidiasis]

BACKGROUND

Fungal agents, chiefly Candida albicans, are the cause of rising morbidity and mortality in newborn infants weighing less than 1500 g. We studied the particular cutaneous effects during the course of these infections.

PATIENTS AND METHODS

This was a retrospective 3-year study in premature infants weighing less than 1500 g and hospitalized in the neonatal department of the Lille University Teaching Hospital. The patients included in the study presented sepsis with isolation of Candida in blood and/or urine culture.

RESULTS

Twelve infants were included (1.8%). The risk factors seen are those described in literature (broad-spectrum antibiotics, prolonged mechanical ventilation and parenteral nutrition, corticosteroids and central venous catheters). Infection occurred early (mean: D12) and affected extremely premature infants (mean: 25 weeks' amenorrhea) of low birth weight (mean: 758 g) generally born by vaginal delivery (9 of 12 infants). The sole fungal agent isolated was Candida albicans. In 10 of the 12 patients, a characteristic skin disorder was observed (erythema with erosion and desquamation). In 10 of the 12 patients, too, Candida was isolated from skin and/or mucosal samples.

DISCUSSION

Although it is now universally accepted that antifungal treatment should be initiated without delay for candidemia in septic newborn infants at risk, diagnosis of systemic candidiasis remains delicate. However, a specific pattern of skin involvement is very commonly seen that is atypical for candidiasis, but which in addition to its diagnostic value indicates early colonization with Candida (first 2 weeks of life). In this setting of immaturity of the skin and immune system, colonization and proliferation in skin and/or mucosa appear to constitute the first stage of systemic infection and we may speak of invasive cutaneous-mucosal candidiasis in extremely premature infants and initiate treatment designed to prevent the disease becoming systemic..

Invasive Candida infections in the neonate

Advances in medical therapy have increased premature infant survival. A rise in Candida infections in neonatal intensive care units (NICUs) has followed. Once considered a contaminant, Candida is now recognized as a major cause of mortality and morbidity within these units. We will examine what is known about the epidemiology, risk factors and end-organ involvement of Candida infections with a focus on invasive disease. In addition, diagnostic alternatives to traditional blood culture, experience with antifungal agents for prophylaxis and therapeutic options, including newer antifungal agents, will be presented.

Neonatal cutaneous fungal infections

PURPOSE OF REVIEW

Cutaneous fungal infections are not uncommon in newborns and are seen in premature or otherwise immunocompromised neonates as well as in healthy full-term neonates. Healthy newborns can develop clinical manifestations as a result of infection with Candida species or as a result of skin colonization with Malassezia species; cutaneous infection with other fungal pathogens is rare. Immunocompromised and premature neonates, however, are susceptible to infection with opportunistic pathogens and are also at higher risk for invasive infection with common pathogens such as Candida. This review discusses the fungal species associated with cutaneous fungal infection in neonates, emphasizes the relevant clinical features, and also reviews the use of newer antifungal agents, including lipid-associated amphotericin B, voriconazole, and caspofungin.

RECENT FINDINGS

Neonatal cutaneous infections with opportunistic fungal pathogens, including Aspergillus and the Zygomycetes, have been reported with increasing frequency as advances in neonatal care have improved the survival rate in very low birthweight neonates. Although these infections are frequently fatal, survival in some neonates has been reported with the use of aggressive surgical debridement and systemic antifungal therapy. Newer antifungal agents, including voriconazole and caspofungin, show promise in the treatment of potentially fatal fungal infections in neonates.

SUMMARY

Cutaneous fungal infections in neonates range from generally benign conditions such as congenital candidiasis and neonatal cephalic pustulosis to potentially fatal infections with opportunistic pathogens in very low birthweight or immunocompromised neonates. The prompt recognition and appropriate treatment of cutaneous fungal disease in neonates is critical to the prevention of adverse outcomes.

Fungal infection in the very low birthweight infant

PURPOSE OF REVIEW

Fungal infections are prevalent in very low birthweight (<1500 g) infants and are associated with significant morbidity and mortality. A better understanding of the adherence factors, molecular diagnostics and risk factors for invasive fungal infection are important in treatment and prevention.

RECENT FINDINGS

Animal studies have demonstrated that Candida readily adheres to apical microvilli and the junctions between enterocytes. Although antibiotics facilitate colonization, dissemination occurs with immunosuppression. The INT1 gene is associated with enhanced colonization and dissemination in these animal models. Dissemination is probably caused by yeast cell adherence and invasion, whereas tissue injury may be related to filamentous formation. Polymerase chain reaction techniques have demonstrated promise in neonatal patients and may not only detect bloodstream infection, but fungal infection at other sites. At the time of fungal sepsis, less than 28 weeks' gestation, thrombocytopenia, and previous exposure to broad-spectrum antibiotics continue to be risk factors for infection. Empiric therapy is still being defined and investigated. Fluconazole prophylaxis should be strongly considered in the most immature infants.

SUMMARY

Preventative strategies against fungal colonization and infection are critical in high-risk very low birthweight infants. Also promising is the ability of molecular diagnostics to detect infection earlier, allowing for prompt treatment, including central venous catheter removal. Identifying the highest risk very low birthweight infants for prophylaxis and empiric therapy may lead to better outcomes. Multicenter clinical trials of fluconazole prophylaxis to confirm its safety and efficacy, and of empiric treatment to test safety and outcomes are urgently needed.

Clinical microbiology of bacterial and fungal sepsis in very-low-birth-weight infants

Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.