Organism-specific platelet response and factors affecting survival in thrombocytopenic very low birth weight babies with sepsis

Relationship between thrombocytopenia and prognosis in children with septic shock: a retrospective cohort study

Septic shock is a life-threatening disease worldwide often associated with thrombocytopenia. Platelets play a crucial role in bridging the gap between immunity, coagulation, and endothelial cell activation, potentially influencing the course of the disease. However, there are few studies specifically evaluating the impact of thrombocytopenia on the prognosis of pediatric patients. Therefore, the study investigates effects of early thrombocytopenia in the prognosis of children with septic shock. Pediatric patients with septic shock from 2015 to 2022 were included monocentrically. Thrombocytopenia was defined as a platelet count of <100 × 109/L during the first 24 hours of septic shock onset. The primary outcome was the 28-day mortality. Propensity score matching was used to pair patients with different platelet counts on admission but comparable disease severity. A total of 419 pediatric patients were included in the analysis. Patients with thrombocytopenia had higher 28-day mortality (55.5% vs. 38.7%, p = .005) compared to patients with no thrombocytopenia. Thrombocytopenia was associated with reduced 28-PICU free days (median value, 0 vs. 13 days, p = .003) and 28-ventilator-free (median value, 0 vs. 19 days, p = .001) days. Among thrombocytopenia patients, those with platelet count ≤50 × 109/L had a higher 28-day mortality rate (63.6% vs. 45%, p = .02). Multiple logistic regression showed that elevated lactate (adjusted odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.04-1.17; P <0.001) and white blood cell (WBC) count (OR = 0.97; 95% CI: 0.95-0.99; p = .003) were independent risk factors for the development of thrombocytopenia. Thrombocytopenia group had increased bleeding events, blood product transfusions, and development of organ failure. In Kaplan-Meier survival estimates, survival probabilities at 28 days were greater in patients without thrombocytopenia (p value from the log-rank test, p = .004). There were no significant differences in the type of pathogenic microorganisms and the site of infection between patients with and without thrombocytopenia. In conclusion, thrombocytopenia within 24 hours of shock onset is associated with an increased risk of 28-day mortality in pediatric patients with septic shock.

Prognostic value of blood inflammatory parameters for predicting mortality in neonates with sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality in neonates. The diagnosis of neonatal sepsis has been widely explored using blood inflammatory parameters. However, few researches have focused on the predictive significance of blood inflammation parameters for predicting mortality. This study aimed to evaluate the prognostic value of blood inflammatory parameters, including white blood cell (WBC), neutrophil, lymphocyte, monocyte, platelet and C-reactive protein (CRP) for predicting mortality in neonates with sepsis.

METHODS

Neonates with culture-proven sepsis were enrolled in this study. The clinical characteristics and levels of white blood cell, neutrophil, lymphocyte, monocyte, platelet and CRP were recorded. The receiver-operating characteristic (ROC) curve was applied to calculate the area under the curve (AUC) and determine the optimal cutoff values. Multivariable Cox regression model was used to evaluate the independent prognostic significance of variables. Kaplan-Meier curve was used to assess survival.

RESULTS

A total of 188 neonates with culture-proven sepsis were included for analysis. The 7-day mortality rate was 11.2 % (21/188) and the 28-day mortality rate was 13.8 % (26/188). The levels of white blood cell, neutrophil, monocyte and platelet in non-survivors were lower than those in survivors (P < 0.05). Platelet yielded higher AUC values than other parameters for predicting mortality with the best cutoff value of 132 × 109/L, followed by WBC with the optimal cutoff value of 6.15 × 109/L. Multivariable Cox regression analysis showed platelet and WBC were independent prognostic factors for predicting mortality. Low platelet group showed lower survival according to Kaplan-Meier method.

CONCLUSIONS

In conclusion, the levels of platelet and WBC on the day of sepsis onset are valuable indicators for predicting mortality in neonates with sepsis.

Thrombocytopenia as an important determinant of poor prognosis in patients with pyogenic liver abscess: a retrospective case series

BACKGROUND

Thrombocytopenia and poor prognosis in severe conditions are associated. However, the clinical significance of thrombocytopenia in pyogenic liver abscess (PLA) has not been evaluated.

OBJECTIVE

To evaluate the association between thrombocytopenia and the prognosis of patients with PLA.

METHODS

A consecutive case series of 458 adult patients with PLA hospitalized at Tongji Hospital (Wuhan, China) between October 2011 and June 2021 was included in this cross-sectional analysis. Patient data were compared between the thrombocytopenia and non-thrombocytopenia groups. Multivariate logistic regression, receiver operating characteristic (ROC) curve and propensity score -matched analyses (PSM) were performed.

RESULTS

Of the 458 patients with PLA, 94 (20.5%) developed thrombocytopenia, 19 (4.1%) developed septic shock, 14 (3.1%) were admitted to the ICU, and 15 (3.3%) died during hospitalization. Thrombocytopenia was independently associated with shock (95%CI = 3.529-57.944, P < 0.001), ICU admission (95%CI = 1.286-25.733, P = 0.022), and mortality (95%CI = 1.947-34.223, P = 0.004) in multivariate regression analysis. ROC analysis showed that thrombocytopenia may be an identified marker of shock [area under the ROC curve (AUC), 0.8119; cut-off, 92.50; P < 0.0001], ICU admission (AUC, 0.7484; cut-off, 82.50; P < 0.0015), and mortality (AUC, 0.7827; cut-off, 122.50; P < 0.002). These findings remained consistent across 86 pairs of patients analyzed for PSM analyses.

CONCLUSIONS

Thrombocytopenia is an independent risk factor for poor prognosis in PLA and patients may be more prone to adverse outcomes.

Diet Modulates the High Sensitivity to Systemic Infection in Newborn Preterm Pigs

Background: Preterm infants are born with an immature immune system, limited passive immunity, and are at risk of developing bacteremia and sepsis in the postnatal period. We hypothesized that enteral feeding, with or without added immunoglobulins, improves the clinical response to systemic infection by coagulase negative staphylococci.

Methods: Using preterm cesarean delivered pigs as models for preterm infants, we infused live Staphylococcus epidermidis (SE, 5 × 10⁹ colony forming units per kg) systemically 0–3 days after birth across five different experiments. SE infection responses were assessed following different gestational age at birth (preterm vs. term), enteral milk diets (bovine colostrum, infant formula with or without added porcine plasma) and with/without systemic immunoglobulins. Pigs infected with SE were assessed 12–48 h for clinical variables, blood bacteriology, chemistry, hematology, and gut dysfunction (intestinal permeability, necrotizing enterocolitis lesions).

Results: Adverse clinical responses and increased mortality were observed in preterm vs. term pigs, when infected with SE just after birth. Feeding bovine colostrum just after birth improved blood SE clearance and clinical status (improved physical activity and intestinal structure, fewer bone marrow bacteria), relative to pigs fed infant formula. A few days later, clinical responses to SE bacteremia (hematology, neutrophil phagocytic capacity, T cell subsets) were less severe, and less affected by different milk diets, with or without added immunoglobulins.

Conclusion: Prematurity increases the sensitivity of newborn pigs to SE bacteremia, potentially causing sepsis. Sensitivity to systemic SE infection decreases rapidly in the days after preterm birth. Both age and diet (parenteral nutrition, colostrum, milk, formula) may influence gut inflammation, bacterial translocation and systemic immune development in the days after birth in preterm newborns.

Late-onset sepsis caused by Gram-negative bacteria in very low birth weight infants: a systematic review

INTRODUCTION

Very low birth weight (VLBW) infants are highly susceptible to late-onset sepsis (LOS). Compared to Gram-positive bacteria, Gram-negative bacteria are less common to cause LOS, but are associated with a more severe clinical manifestation, higher mortality, and increased risk of neonatal morbidity. So far, the clinical picture of late-onset Gram-negative sepsis (LOGNS) in VLBW infants has not been elucidated. An up-to-date and thorough understanding of the clinical picture of LOGNS in VLBW infants is important to optimize current anti-sepsis protocols. Areas covered: Literature published in the last three decades was searched for data on the epidemiology, pathogen profile, risk factors, clinical manifestations, laboratory parameters, mortality, and short-term and long-term morbidity of LOGNS in VLBW infants. Expert opinion: Gram-negative bacteria are major contributors of neonatal morbidity and mortality in VLBW infants with LOS, potentially posing a significant disease burden. Unravelling the pathogen-specific clinical picture of LOGNS and the underlying mechanisms is of particular interest. VLBW infants may differ from more mature neonates in terms of disease burden and clinical course of LOGNS. Epidemiologic studies aided by advanced molecular techniques may help to develop anti-sepsis protocols specialized for VLBW infants, with strategies targeting Gram-negative bacteria.

Thrombocytopenia in bacteraemia and association with bacterial species

Thrombocytopenia is common in patients with invasive bacterial infections. Bacteria can activate platelets, but it is unclear if this affects platelet count. The aim of this study was to examine whether bacteraemia with Staphylococcus aureus, which readily activate human platelets, was more likely to be complicated by thrombocytopenia than bacteraemia with Escherichia coli or Streptococcus pneumoniae with different abilities to activate platelets.We compared information from 600 adult patients with community-acquired bacteraemia with S. aureus (n = 140), E. coli (n = 420) and S. pneumoniae (n = 40) in Southern Sweden, 2012, linking information on positive blood cultures from microbiological databases and medical charts. The proportion of patients with thrombocytopenia (platelet count <150 × 109/ml) was calculated. Logistic regression was used to estimate the odds ratios (OR) for thrombocytopenia according to bacterial species adjusted for confounders.The proportion of thrombocytopenia was 29% in S. aureus, 28% in E. coli and 20% in S. pneumonia bacteraemia (P = 0.50), corresponding to an OR of 1.2 (95% confidence interval 0.7-1.9) for thrombocytopenia for S. aureus as compared with E. coli or S. pneumoniae, adjusted for confounders.This study indicates that platelet activation by bacteria is not a major causative mechanism in sepsis-associated thrombocytopenia.

Thrombocytopenia in neonatal sepsis: Incidence, severity and risk factors

Objectives

Thrombocytopenia is a frequent problem in neonatal sepsis and is among the most predictive, independent risk factors for sepsis-associated mortality. This study aims to clarify the occurrence, severity and duration of thrombocytopenia in neonatal sepsis.

Study design

A cohort study was carried out among all neonates with proven culture positive sepsis that were admitted to a tertiary NICU between 2006 and 2015 (n = 460). The occurrence, severity and duration of thrombocytopenia were recorded, as well as major bleedings and potential risk factors for mortality in neonatal sepsis.

Results

Sepsis was diagnosed in 460 of 6551 neonates (7%). Severe thrombocytopenia (platelets ≤50*10⁹/L) occurred in 20% (92/460) of septic neonates. The median time for platelets to rise >100*10⁹ was 6.0 days (interquartile range 4.0–7.0). On multivariate analysis, maternal hypertension, intravascular thrombosis and Gram negative (as opposed to Gram positive) sepsis were independently associated with thrombocytopenia in neonatal sepsis. In severe thrombocytopenia, 10% (9/92) suffered a severe IVH, compared to 5% (20/356) in neonates with platelets >50*109/L (p = 0.125). 10% (9/92) suffered a pulmonary hemorrhage, compared to 2% (9/368) in neonates with platelets >50*109/L (p = 0.001). On multivariate analysis, thrombocytopenia and Gram negative (as opposed to Gram positive) sepsis were independently associated with neonatal mortality.

Conclusions

Thrombocytopenia is independently associated with maternal hypertension, intravascular thrombosis and Gram negative sepsis. Thrombocytopenia in neonatal sepsis increases the risk of mortality nearly four-fold, with another six-fold increase in mortality in case of Gram negative sepsis.

Effect of Severe Maternal Iron Deficiency Anemia on Neonatal Platelet Indices

OBJECTIVE

To evaluate the effect of maternal iron deficiency anemia (IDA) on fetal thrombopoiesis.

METHODS

In this prospective observational study, maternal and cord blood iron status parameters (serum iron, serum ferritin, total iron-binding capacity, and transferrin saturation), and platelet indices, such as, absolute platelet count (APC), mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit, were estimated in a convenient sample of 142 mothers with IDA (hemoglobin <11 g/dl and serum ferritin <12 ng/ml) and an equal number of healthy non-anemic (hemoglobin ≥11 g/dl) mothers, who delivered singleton live neonates at term gestation. Mothers with antenatal thrombocytopenia, infections, inflammatory conditions, pregnancy-induced hypertension and neonates with perinatal asphyxia, sepsis and congenital malformations were excluded.

RESULTS

For statistical analysis, the IDA group was further subdivided into mild-to-moderate (hemoglobin 7-10.9 g/dl) and severe (hemoglobin <7 g/dl) anemia. Cord blood APC and PDW were comparable between non-anemic and mild-to-moderate anemic mothers (242,550 ± 54,320/μL vs. 235,260 ± 34,620/μL for APC and 16.2 ± 1.4 vs. 16.4 ± 1.8 fl for PDW, respectively), but in severe IDA group, cord blood APC and PDW were significantly lower (74,520 ± 12,380/μL and 17.8 ± 2.1 fl, respectively, p < 0.001). MPV and plateletcrit were comparable. None of the study neonates had a platelet count <30,000/μL or showed any evidence of clinical bleeding.

CONCLUSIONS

Neonates born to mothers with severe IDA had moderate thrombocytopenia with increased PDW, though no change was observed in MPV and plateletcrit. Further studies should be carried out to identify the cause and consequences of this observation.

Platelet Mass Predicts Intracranial Hemorrhage in Neonates With Gram-negative Sepsis

Neonatal sepsis due to gram-negative bacteria is associated with severe hemorrhagic conditions, such as intracranial hemorrhage (ICH). The aim of the study was to investigate the significance of platelet (PLT) count and platelet mass (PM) in predicting promptly neonatal ICH. Demographics, species, PLT, PM, ICH, and outcome for neonates with gram-negative sepsis for the period 2005 to 2012 were retrospectively recorded. Eighty-four infants were enrolled with median gestational age 30 weeks, median birthweight 1481.5 g, and median age at sepsis diagnosis 23 days. The most frequently isolated bacteria were Enterobacter spp. (38.1%). ICH occurred in 16 neonates (19%), whereas the mortality rate was 25% (21 neonates). The median PLT count and PM at days 1, 2, and 3 after diagnosis of gram-negative sepsis was significantly associated with the presence of ICH. Regression analysis revealed the cutoff predictive value of 355 fL/nL for the PM at day 3 (area under the curve: 75, sensitivity 90%, P=0.002). PM levels could play an important role in predicting the occurrence of ICH in high-risk neonates.

Prognostic significance of early platelet count decline in preterm newborns

OBJECTIVES

Decline of platelets with or without thrombocytopenia is observed in critically ill preterm newborns. Prognostic significance of platelets count in Neonatal Intensive Care Unit focused on outcome after thrombocytopenia. We aimed to estimate the changes in platelets count within the first 7 days of life in preterm newborns and its relation to final outcomes.

METHODS

Retrospectively, the platelets count during the first 7 days of life, and its association with mortality, length of stay among survivors (LOS), and later severe morbidities were determined. Appropriate regression analyses were used to examine possible relations between studied variables.

RESULTS AND DISCUSSION

Platelets drop that did not reach thrombocytopenia level in the first 7 days of life happened in 61.7%. Platelets count drop in the first 7 days of life was a predictor of mortality, LOS, and major morbidities such as intraventricular hemorrhage and necrotizing enterocolitis.

CONCLUSIONS

Platelets count drop within the first 7 days of life independent of thrombocytopenia can be used to predict increased mortality, LOS, and the development of later severe morbidities in critically ill preterm neonates.

Platelets in inflammation and infection

Although platelets are traditionally recognized for their central role in hemostasis, many lines of research clearly demonstrate these rather ubiquitous blood components are potent immune modulators and effectors. Platelets have been shown to directly recognize, sequester and kill pathogens, to activated and recruit leukocytes to sites of infection and inflammation, and to modulate leukocyte behavior, enhancing their ability to phagocytose and kill pathogens and inducing unique effector functions, such as the production of Neutrophil Extracellular Traps (NETs). This multifaceted response to infection and inflammation is due, in part, to the huge array of soluble mediators and cell surface molecules expressed by platelets. From their earliest origins as primordial hemocytes in invertebrates to their current form as megakaryocyte-derived cytoplasts, platelets have evolved to be one of the key regulators of host intravascular immunity and inflammation. In this review, we present the diverse roles platelets play in immunity and inflammation associated with autoimmune diseases and infection. Additionally, we highlight recent advances in our understanding of platelet behavior made possible through the use of advanced imaging techniques that allow us to visualize platelets and their interactions, in real-time, within the intact blood vessels of a living host.

[Thrombopenia and the nature of the microorganism in infected critically ill children]

BACKGROUND

Thrombopenia is correlated with sepsis and mortality in pediatric intensive care units. The purpose of this study was to find an association between thrombopenia and the microorganism type to guide the choice of empiric antibiotic therapy in infected critically ill children.

MATERIALS AND METHODS

We conducted a prospective descriptive study, including all newborns, infants, and children admitted to a pediatric surgical intensive care unit from 1st January to 31st December 2009. We identified patients who developed an infection and/or thrombopenia (platelet count less than 100,000/mm(3)) during hospitalization.

RESULTS

One hundred ninety-seven patients were included (57 newborns, 41 infants, 99 children). Ninety patients developed 100 infectious episodes during the study period. Of the 57 newborns enrolled in the study, 31 (54%) developed 37 infections. Seventy-six microorganisms (55 Gram-negative bacilli [GNB], 17 Gram-positive cocci, two Gram-negative cocci, two fungal pathogens) were identified during 65 infectious episodes in 55 patients. Thirty-four episodes of thrombopenia were observed in 30 patients. Thrombopenia was observed only in infected patients (P<0.001). Thrombopenia was associated with infections caused by GNB (26/28 vs 20/37, P=0.001) and by Klebsiella (16/28 vs 6/37, P=0.001) and may be associated with infections caused by GNB producing extended-spectrum beta-lactamases (P=0.07). Gram-positive cocci infections were correlated to the non-occurrence of thrombopenia (P=0.02). Postoperative peritonitis was also significantly associated with thrombopenia (P=0.03). The mortality rate in our patients was 12.7% (22.8% in neonates). There was an association between thrombopenia and death in univariate analysis (11/25 vs 19/172, P<0.001). Multivariate logistic regression analysis did not confirm thrombopenia as an independent predictive factor of mortality in children.

CONCLUSION

Because of the relatively high proportion of resistant GNB, an empiric antibiotic therapy combining a carbapenem and an aminoglycoside may be indicated in infected critically ill children developing thrombopenia.

Clinical and laboratory factors that predict death in very low birth weight infants presenting with late-onset sepsis

BACKGROUND

Late-onset sepsis (LOS) in very low birth weight (VLBW) infants is associated with significant morbidity and mortality. The ability to predict mortality in infants with LOS based on clinical and laboratory factors at presentation of illness remains limited.

OBJECTIVES

To identify predictors of sepsis-associated mortality from a composite risk profile that includes demographic data, category of infecting organism, clinical and laboratory data at onset of illness.

STUDY DESIGN

Data were collected from VLBW infants with at least 1 episode of LOS admitted to Yale Neonatal Intensive Care Unit from 1989 through 2007. Episodes were categorized as Gram-positive, Gram-negative or fungal. Multivariate logistic regression analysis was used to compare and contrast different types of infections and to assess independent risk factors for death.

RESULTS

Four hundred twenty-four cases of LOS were identified in 424 VLBW infants. Of these, 262 (62%) were categorized as Gram-positive, 126 (30%) as Gram-negative and 36 (8%) as fungal. Multivariate analyses revealed that infants with Gram-positive infections had significantly lower odds of death compared to those with Gram-negative (adjusted odds ratio: 0.17; 95% confidence interval: 0.08-0.36) or fungal LOS (adjusted odds ratio: 0.22; 95% confidence interval: 0.07-0.64). Need for intubation, initiation of pressors, hypoglycemia and thrombocytopenia as presenting laboratory signs of infection and necrotizing enterocolitis were independent risk factors for sepsis-related death.

CONCLUSIONS

We identified presenting clinical and laboratory factors, including category of infecting organism, which predict the increased risk of LOS-related death. This information can be useful in estimating prognosis shortly after the onset of disease.

Restoration of antioxidant enzymes in the therapeutic use of selenium in septic patients

A prospective observational study of parenteral selenium supplementation started in January 2008 which included 72 septic patients with APACHE II scores ranging from 19 to 40 after admission.Patients were divided into two major groups: one with a continual infusion of sodium selenite at 750 µg/24 h for 6 days and a placebo group followed by subgroups according to the presence or absence of surgical procedure. Routine biochemical and hematological para-meters were determined continuously. Sequential Organ Failure Assessment (SOFA) scores were calculated in two-day intervals.Patients who died had a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score, lower albumin on the 3rd days of therapy and higher C-reactive protein (CRP) on the 6th days of therapy. Statistically, there was no significant difference in the comparison of CRP, fibrinogen, albumin, plasma proteins, or neutrophil to lymphocyte counts during the 6 days in all subgroups. There was a significant difference in the comparison of leukocytes on the 6th day of therapy. Glutathione peroxidase and glutathione reductase activity was increased in selenium subgroups with negative correlation in placebo subgroups during the therapy. A downward trend in SOD activity, more appreciable in selenium groups, seemed to be a reflection of lower superoxide radical production. This is biased more as a result of GPx activity restoration, preventing further peroxidation of organic substrates and cyclic formation of other radicals, than actual attenuation of their production.Selenium substitution increased selenium dependent antioxidant enzyme activity and, in comparing mortality in groups, we found a 16.7 % decrease in mortality in favor of supplementation with selenium.

Prevalence and pathogen distribution of neonatal sepsis among very-low-birth-weight infants

BACKGROUND

Neonatal sepsis contributes to great mortality and morbidity among very-low-birth-weight (VLBW) infants. Prevalence and pathogen distribution of sepsis in the neonatal intensive care units (NICUs) vary with time and geographic location. Such information serves as a guide for selection of empirical antibiotics coverage.

METHODS

This is a case series study performed by retrospective chart review of VLBW infants (birth body weight, BBW, <1500 g) in a medical center during a 5-year period from January 2005 to December 2009. Episodes of positive blood cultures, pathogen distribution and related clinical manifestations were described.

RESULTS

A total of 158 episodes of sepsis were identified from 1042 VLBW infants. Sepsis rate was 152 per 1000 live births. The vast majority of infections (60.7%) were caused by Gram-positive organisms [G(+)], and overall Coagulase-negative staphylococci (CoNS) (52.5%) were the most common pathogen identified. Prevalence for early-onset sepsis (EOS) was 1% and for late-onset sepsis (LOS) was 14.2%. Infants with EOS had a much higher case fatality rate than LOS (40% vs. 4.7%). Escherichia coli (40%) were the leading pathogen of EOS while CoNS (54.7%) was the leading pathogens of LOS. Overall, apnea and/or bradycardia and/or cyanosis (65.8%), poor activity (48.7%), and increased respiratory effort (43.0%) were the most common presenting features of sepsis.

CONCLUSION

Unlike term infants, Gram-negative organism and E coli were the leading pathogen of EOS among VLBW infants. Judicious and timely use of antibiotic therapy is crucial in the care of VLBW infants.

Drop in platelet counts in extremely preterm neonates and its association with clinical outcomes

BACKGROUND

Thrombocytopenia is a common finding among preterm neonates and has been associated with mortality and morbidities. In recent studies in adults, the drop in platelet numbers has been shown to be a predictor of clinical outcomes. Although drop in the platelet counts with or without thrombocytopenia has also been observed in neonates, its association with mortality and morbidity has not been investigated in the preterm population.

OBJECTIVE

To study the prevalence of a ≥ 30% drop in platelet counts in preterm neonates and its association with clinical outcomes.

METHODS

Retrospective chart review was done on neonates born at gestational age ≤ 28 weeks and survived for ≥ 7 days. As with the adult studies, a ≥30% drop in platelet numbers were identified at 7 days and 28 days of age and their association with mortality, morbidities, and length of stay (LOS) was investigated.

RESULTS

Two hundred eighty-six patients included in the study had a mean gestational age of 26.3 weeks (range, 23 to 28 wk) and birth weight of 899 ± 215 grams. A ≥ 30% drop in platelet counts occurred in 68.1% neonates. It was significantly associated with mortality (P < 0.001), morbidities at both 7 and 28 days [intraventricular bleed (P < 0.01)], retinopathy of prematurity (P<0.01), necrotizing enterocolitis (P < 0.05) and gram-positive infections (P < 0.05), and LOS (P < 0.01). Only those neonates who had a ≥ 30% drop in the platelet numbers developed gram negative and fungal infections. These associations of clinical morbidities and mortality with a ≥ 30% drop in platelet counts were independent of thrombocytopenia.

CONCLUSIONS

A ≥ 30% drop in platelet counts is associated with increased mortality, morbidities, and LOS in preterm neonates, independent of thrombocytopenia. As the drop occurs before the onset of clinical morbidity, one potential application is its use to predict the onset of morbidities including necrotizing enterocolitis, intraventricular hemorrhage, and retinopathy of prematurity, and a prolonged LOS and mortality.

Challenging issues in neonatal candidiasis

In an era of quality improvement and 'getting to zero (infections and/or related mortality),' neonatal candidiasis is ripe for evidence-based initiatives. Knowledge of each institution's invasive Candida infection (ICI) incidence and infection-related mortality is critical to evaluate disease burden and effective interventions. Evidenced-based interventions include: antifungal prophylaxis, starting with appropriate dosing, and prompt removal of central venous catheters (CVC). There is A-I evidence supporting antifungal prophylaxis with fluconazole, and it should be considered in every neonatal intensive care unit (NICU). The literature supports targeting infants <1000 g and/or <or=27 weeks, because this group has high infection-related mortality and neurodevelopmental impairment in 57% of survivors. Antifungal prophylaxis has been shown to nearly eliminate infection-related mortality. Interventions start with prenatal initiatives, with women being treated for vaginal candidiasis, especially with preterm labor or complications. Targeting modifiable risk factors, including restriction policies for use of third- and fourth-generation cephalosporins, carbapenems, H2-antagonists, proton pump inhibitors, and postnatal steroids; guidelines for CVC care and removal; and feeding practices, with promotion of early feedings and breast milk, may also reduce risk. A few studies have emerged on empiric antifungal therapy with sepsis evaluations for preterm infants <1500 g and other high-risk patients that have shown favorable effects of eliminating mortality, but these have not been compared to appropriate antifungal therapy and central line removal. Further study of empiric therapy, prospective treatment studies with higher targeted dosing of amphotericin B preparations, fluconazole, and new antifungals with prompt CVC removal may contribute to a 100% survival rate for those infants >1000 g and >or=28 weeks not receiving antifungal prophylaxis. Evaluation of ICI incidence and mortality by gestational age and birth week should be followed in each NICU, to evaluate infection control and prevention.

Bacterial-platelet interactions: virulence meets host defense

Platelets have historically been viewed as cell fragments that only mediate blood coagulation. Yet, platelets have as - or perhaps even more - important roles in tissue remodeling, modulation of inflammation and antimicrobial host defense. It is evident that platelets interact with prokaryotes directly and indirectly through multiple molecular and cellular mechanisms. The important roles of platelets in antibacterial host defense can be exemplified through contemporary themes in platelet immunobiology. Platelets have unambiguous structures and functions of host defense effector cells. Recent discoveries reveal platelet expression of toll-like and purinonergic receptors, which enable detection and response to bacterial infection, degranulation of an array of microbicidal peptides and coordination of other molecular and cellular host defenses. From multiple perspectives, platelets are now increasingly recognized as critical innate immune effector cells that also bridge and facilitate optimization of adaptive immunity. It follows that clinical deficiencies in platelet quantity or quality are now recognized correlates of increased risk and severity of bacterial and other infections. Along these lines, new evidence suggests that certain prokaryotic organisms may be capable of exploiting platelet interactions to gain a virulence advantage. Indeed, certain bacterial pathogens appear to have evolved highly coordinated means by which to seize opportunities to bind to surfaces of activated platelets, and exploit them to establish or propagate infection. Hence, it is conceivable that certain bacterial pathogens subvert platelet functions. From these perspectives, the net consequences of bacterial virulence versus platelet host defenses likely decide initial steps towards the ultimate result of infection versus immunity.

Platelets in defense against bacterial pathogens

Platelets interact with bacterial pathogens through a wide array of cellular and molecular mechanisms. The consequences of this interaction may significantly influence the balance between infection and immunity. On the one hand, recent data indicate that certain bacteria may be capable of exploiting these interactions to gain a virulence advantage. Indeed, certain bacterial pathogens appear to have evolved specific ways in which to subvert activated platelets. Hence, it is conceivable that some bacterial pathogens exploit platelet responses. On the other hand, platelets are now known to possess unambiguous structures and functions of host defense effector cells. Recent discoveries emphasize critical features enabling such functions, including expression of toll-like receptors that detect hallmark signals of bacterial infection, an array of microbicidal peptides, as well as other host defense molecules and functions. These concepts are consistent with increased risk and severity of bacterial infection as correlates of clinical abnormalities in platelet quantity and quality. In these respects, the molecular and cellular roles of platelets in host defense against bacterial pathogens are explored with attention on advances in platelet immunobiology.