Platelet count and sepsis in very low birth weight neonates: is there an organism-specific response?

Prophylactic fluconazole is effective in preventing fungal colonization and fungal systemic infections in preterm neonates: a single-center, 6-year, retrospective cohort study

OBJECTIVE

Despite the promising preliminary results observed in extremely low birth weight (ELBW) populations, the use of fluconazole to prevent fungal colonization and infection in preterm neonates in the NICU is still an open question and not yet recommended as a standard of care. We have reviewed our 6-year series to assess the effectiveness and safety of this form of prophylaxis.

METHODS

This retrospective study consisted of 465 neonates who weighed < 1500 g at birth and were admitted to our NICU in the period 1998-2003. Those who were born between 1998 and 2000 and did not receive fluconazole prophylaxis (group A, n = 240) were compared with those who were born between 2001 and 2003 and treated with fluconazole until the 30th day of life (45th for neonates < 1000 g at birth; group B, n = 225). Weekly surveillance cultures were obtained from all patients. Incidence of fungal colonization, incidence of systemic fungal infection (SFI), rate of progression from colonization to infection, and mortality rates attributable to fungi were calculated for both groups and separately for neonates who were < 1000 g (ELBW) and were 1001 to 1500 g (NE-VLBW) at birth.

RESULTS

Overall fungal colonization was significantly lower in group B (24.0%) than in group A (43.8%; relative risk [RR]: 0.406; 95% confidence interval [CI]: 0.273-0.605). The same was true of neonates with colonization in multiple sites (2.6% vs 5.8%) and of those with colonization from high-risk sites (5.8% vs 19.2%). SFI incidence was significantly lower in group B (10 of 225 cases; 4.4%) than in group A (40 of 240 cases; 16.7%; RR: 0.233; 95% CI: 0.113-0.447). Reduction of both colonization and SFI in group B was greater in the ELBW neonates and also significant in the NE-VLBW neonates. Rate of progression from colonization to infection was significantly lower in group B (0.17 vs 0.38; RR: 0.369; 95% CI: 0.159-0.815). Crude mortality rate attributable to Candida species was 1.7% (4 of 240) in group A vs 0% (0 of 225) in group B. Overall mortality rate (any cause before hospital discharge) was similar in the two groups (11.2% vs 10.6%), but in colonized infants (n = 159), it was significantly lower in group B (3.7% vs 18.1%; RR: 0.174; 95% CI: 0.039-0.778). The incidence of natively fluconazole-resistant fungal species did not increase over the years, and patterns of sensitivity to fluconazole remained the same. No adverse reaction related to fluconazole occurred.

CONCLUSIONS

Prophylactic fluconazole significantly reduces the incidence of colonization and systemic infection by Candida species in both ELBW and NE-VLBW neonates and decreases the rates of progression from initial colonization to massive colonization and to systemic infection. All VLBW neonates may benefit from fluconazole prophylaxis.

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.

Patterns of thrombocytosis and thrombocytopenia in hospitalized neonates

OBJECTIVE

We sought to identify changes in platelet (PLT) counts over time, and to evaluate the patterns of thrombocytopenia and thrombocytosis in hospitalized infants 23.8 weeks to term gestation.

STUDY DESIGN

Neonates were divided into four gestational age groups and their PLT counts were retrospectively compared for prevalence of thrombocytopenia, thrombocytosis, and associated conditions.

RESULTS

Postconceptional age, postnatal age, and sepsis (among other factors) affected PLT counts. When counts from noninfected appropriately grown infants were evaluated, the risk of thrombocytopenia and thrombocytosis were highest in the most preterm infants, and these risks changed with corrected gestational age. PLT counts increased weekly over the first 4 weeks of life for all but the most preterm infants.

CONCLUSIONS

These data characterize the incidence of thrombocytopenia and thrombocytosis across a wide range of gestational ages and show that, even in noninfected neonates, these conditions are common, and risk decreases with increasing maturity. The age-related changes in PLT patterns may reflect maturation of platelet regulation.

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.

Nosocomial infection in the NICU: a medical complication or unavoidable problem?

Nosocomial sepsis is a serious problem for neonates who are admitted for intensive care. As it is associated with increases in mortality, morbidity, and prolonged length of hospital stay, both the human and fiscal costs of these infections are high. Although the rate of nosocomial sepsis increases with the degree of both prematurity and low birth weight, no specific lab test has been shown to be very useful in improving our ability to predict who has a "real" blood-stream infection and, therefore, who needs to be treated with a full course of antibiotics. As a result, antibiotic use is double the rate of "proven" sepsis and we are facilitating the growth of resistant organisms in the neonatal intensive care unit. The purpose of this article is to review the topic of nosocomial infections in neonates.

Evaluation and treatment of severe and prolonged thrombocytopenia in neonates

Thrombocytopenia is one of the most common hematologic problems in the neonatal intensive care unit (NICU). Despite its prevalence,several basic pathophysiologic questions remain unanswered. For instance, there is a lack of evidence-based guidelines for treatment,and the kinetic mechanisms (decreased platelet production,increased platelet consumption, or sequestration) responsible for most varieties of neonatal thrombocytopenia are not well defined.Moreover, a clear correlation between degree of thrombocytopenia and the resulting bleeding risk has not been demonstrated, and no transfusion-trigger studies have been conducted in neonates. As a consequence of these deficiencies in knowledge, there is great variability in platelet transfusion practices among NICUs. This article presents an overview of the evaluation of a neonate with severe thrombocytopenia and a review of current and projected therapeutic options.