Two Gene Set Variation Index as Biomarker of Bacterial and Fungal Sepsis.

BACKGROUND: The incidence of sepsis has been increasing in recent years. The molecular mechanism of different pathogenic sepsis remains elusive, and biomarkers of sepsis against different pathogens are still lacking. METHODS: The microarray data of bacterial sepsis, fungal sepsis, and mock-treated samples were applied to perform differentially expressed gene (DEG) analysis to identify a bacterial sepsis-specific gene set and a fungal sepsis-specific gene set. Functional enrichment analysis was used to explore the body's response to bacterial sepsis and fungal sepsis. Gene set variation analysis (GSVA) was used to score individual samples against the two pathogen-specific gene sets, and each sample gets a GSVA index. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of sepsis. An independent data set was used to validate the bacterial sepsis-specific GSVA index. RESULTS: The genes differentially expressed only in bacterial sepsis and the genes differentially expressed only in fungal sepsis were significantly involved in different biological processes (BPs) and pathways. This indicated that the body's responses to fungal sepsis and bacterial sepsis are varied. Twenty-two genes were identified as bacterial sepsis-specific genes and upregulated in bacterial sepsis, and 23 genes were identified as fungal sepsis-specific genes and upregulated in fungal sepsis. ROC curve analysis showed that both of the two pathogen sepsis-specific GSVA indexes may be a reliable biomarker for corresponding pathogen-induced sepsis (AUC = 1.000), while the mRNA of CALCA (also known as PCT) have a poor diagnostic value with AUC = 0.512 in bacterial sepsis and AUC = 0.705 in fungi sepsis. In addition, the AUC of the bacterial sepsis-specific GSVA index in the independent data set was 0.762. CONCLUSION: We proposed a bacterial sepsis-specific gene set and a fungal sepsis-specific gene set; the bacterial sepsis GSVA index may be a reliable biomarker for bacterial sepsis.

Prospective evaluation of SeptiFast Multiplex PCR in children with systemic inflammatory response syndrome under antibiotic treatment.

BACKGROUND: Antimicrobially pre-treated children with systemic inflammation often pose a diagnostic challenge to the physician. We aimed to evaluate the additional use of SeptiFast multiplex polymerase chain reaction (PCR) to identify causative pathogens in children with suspected systemic bacterial or fungal infection. METHODS: Prospective observational study in 39 children with systemic inflammatory response syndrome (SIRS) under empiric antibiotic treatment. Primary outcome was the rate of positive blood cultures (BC), compared to the rate of positive SeptiFast (SF) results. RESULTS: In total, 14 SF-samples yielded positive results, compared to 4 positive BC (p < 0.05). All blood cultures and 13 of 14 positive SF-tests were considered infection. Median time for positive BC was 2 days, and time to definite result was 6 days, compared to 12 h for SF. Antimicrobial therapy was adapted in 7 of the 14 patients with positive SeptiFast, and in 3 of the 4 patients with positive BC. Best predictive power for positive SF shown by receiver-operating characteristic was demonstrated for procalcitonin PCT (Area under the curve AUC: 0.79), compared to C-reactive protein CRP (AUC: 0.51) and leukocyte count (AUC: 0.46). A procalcitonin threshold of 0.89 ng/ml yielded a sensitivity of 0.82 and a specifity of 0.7. Children with a positive SeptiFast result on day 0 had a significantly higher risk to require treatment on the Pediatric Intensive Care Unit or to be deceased on day 30 (Odds-Ratio 8.62 (CI 1.44-51.72). CONCLUSIONS: The additional testing with SeptiFast in antimicrobially pre-treated children with systemic inflammation enhances the rate of pathogen detection. The influence of multiplex PCR on clinically relevant outcome parameters has to be further evaluated. ( TRIAL REGISTRATION: DRKS00004694).

[Iron and invasive fungal infection]. / Hierro e infección fúngica invasiva.

Iron is an essential factor for both the growth and virulence of most of microorganisms. As a part of the innate (or nutritional) immune system, mammals have developed different mechanisms to store and transport this element in order to limit free iron bioavailability. To survive in this hostile environment, pathogenic fungi have specific uptake systems for host iron sources, one of the most important of which is based on the synthesis of siderophores-soluble, low-molecular-mass, high-affinity iron chelators. The increase in free iron that results from iron-overload conditions is a well-established risk factor for invasive fungal infection (IFI) such as mucormycosis or aspergillosis. Therefore, iron chelation may be an appealing therapeutic option for these infections. Nevertheless, deferoxamine -the first approved iron chelator- paradoxically increases the incidence of IFI, as it serves as a xeno-siderophore to Mucorales. On the contrary, the new oral iron chelators (deferiprone and deferasirox) have shown to exert a deleterious effect on fungal growth both in vitro and in animal models. The present review focuses on the role of iron metabolism in the pathogenesis of IFI and summarises the preclinical data, as well as the limited clinical experience so far, in the use of new iron chelators as treatment for mucormycosis and invasive aspergillosis.

Pulmonary cryptococcosis: Clinical, radiographical and serological markers of dissemination.

BACKGROUND AND OBJECTIVE: This study aimed to identify markers of disseminated infection in patients presenting with pulmonary cryptococcosis. METHODS: Patients diagnosed with pulmonary cryptococcosis at a tertiary hospital between April 1998 and April 2005 were included and their clinical, radiological and pathological data analysed retrospectively. RESULTS: Thirty-one patients (14 male) were recruited into the study. Disseminated infection was seen in nine patients (29%), with the isolation of Cryptococcus neoformans from the blood of five patients and the cerebrospinal fluid of seven (three patients had both positive blood and cerebrospinal fluid findings). Patients with disseminated infection had a significantly higher incidence of impaired cellular immunity (immunosuppressant use, AIDS and haematological malignancy) (P = 0.015), fever (P < 0.001), interstitial abnormalities on CXR (P < 0.001), pleural effusion (P = 0.017) and death (P = 0.04) when compared with patients with localized infection. Serum cryptococcal antigen (sCRAG) was positive in 17 of the 19 patients tested at the time of diagnosis. Significantly higher sCRAG titres were noted in patients who had fever (P = 0.001), interstitial abnormalities on CXR (P = 0.004), pleural effusion (P = 0.018), disseminated disease (P = 0.003) and in those who died (P = 0.05). CONCLUSIONS: In pulmonary cryptococcosis patients, the presence of fever, interstitial abnormalities on CXR or pleural effusion should lead clinicians to suspect disseminated infection. High titres of sCRAG may indicate more extensive extra-pulmonary involvement and a worse prognosis.

Mannose-binding lectin deficiency facilitates abdominal Candida infections in patients with secondary peritonitis.

Mannose-binding lectin (MBL) deficiency due to variations in the MBL gene is associated with increased susceptibility to infections. In this study, the association between MBL deficiency and the occurrence of abdominal yeast infection (AYI) in peritonitis patients was examined. Eighty-eight patients with secondary peritonitis requiring emergency laparotomy were included. MBL genotype (wild type [WT] versus patients with variant genotypes), MBL plasma concentrations, and Candida risk factors were examined in patients with and those without AYI (positive abdominal yeast cultures during [re]laparotomy). A variant MBL genotype was found in 53% of patients with AYI and 38% of those without AYI (P = 0.18). A significantly higher proportion of variant patients had an AYI during early peritonitis (during first laparotomy) than WT patients (39% versus 16%, respectively; P = 0.012). Patients with AYI had lower MBL levels than did patients without AYI (0.16 microg/ml [0.0 to 0.65 microg/ml] versus 0.65 microg/ml (0.19 to 1.95 microg/ml); P = 0.007). Intensity of colonization (odds ratio [OR], 1.1; 95% confidence interval [CI], 1.0 to 1.1), MBL plasma concentrations of <0.5 microg/ml (OR, 4.5; 95% CI, 1.2 to 16.3), and numbers of relaparotomies (OR, 1.7; 95% CI, 1.0 to 2.8) were independently associated with AYI. In summary, deficient MBL plasma levels were independently associated with the development of AYI in patients with secondary peritonitis and seemed to facilitate early infection.

Influence of depletion of alveolar macrophages on apoptosis in Candida-induced acute lung injury.

Apoptosis plays an important role in acute lung injury (ALI), and alveolar macrophages (AMs) are known to secrete proinflammatory cytokines and promote alveolar inflammation. The authors have previously reported that AMs can be depleted by inhalation of 1 mM 2-chloroadenosine (2-CA). In this study, the authors evaluated the effect of AM depletion by 2-CA inhalation on apoptosis in Candida-induced ALI. The results of in situ terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling (TUNEL) and immunohistochemical studies and measurement of cytokine levels and caspase 3 activities in lung homogenates indicated that the Fas-FasL system and apoptosis of alveolar epithelial cells are suppressed by depletion of AMs by 2-CA inhalation.

Breakthrough fungal infections in stem cell transplant recipients receiving voriconazole.

Infection with voriconazole-resistant fungi may become problematic, because organisms with decreased susceptibility have been noted. Breakthrough fungal infections occurred in 13 of 139 patients who received voriconazole at our center during the period of September 1998 through September 2003. Zygomycetes were found in 6 patients, and Candida glabrata bloodstream infection occurred in 4 patients. Minimal inhibitory concentrations were > or =1 microg/mL for all available isolates. Yeasts and molds with decreased susceptibility to voriconazole may cause invasive infection in patients treated successfully for aspergillosis.

Treatment of candidaemia in premature infants: comparison of three amphotericin B preparations.

OBJECTIVE: The objective of this study was to compare the effectiveness and tolerability of three antifungal preparations, amphotericin B, liposomal amphotericin B (LamB) and amphotericin B colloidal dispersion (ABCD), in the treatment of neonatal Candida bloodstream infection (CBSI). PATIENTS AND METHODS: All patients hospitalized in the neonatal intensive care unit from 1996 to 2000 with CBSI were enrolled. Patients with a serum creatinine concentration of <1.2 mg/dL received amphotericin B, and those with serum creatinine > or =1.2 mg/dL received LamB or ABCD. Complete blood counts, and renal and hepatic function tests were obtained before, during and after treatment; blood cultures were performed daily until three consecutive cultures were negative. If cultures were positive for more than 10 days with clinical signs of fungal infection and/or persistent thrombocytopenia, a second antifungal drug was added. RESULTS: Fifty-six infants met the study criteria: four term and 52 preterm, including 36 extremely low birth weight infants. Amphotericin B was the initial treatment for 34, LamB for 6 and ABCD for 16 infants. No differences in mortality were found between the three groups. Sterilization of the blood was achieved with amphotericin B in 67.6% of patients, LamB in 83.3% and ABCD in 57.1%, when used as monotherapy; with the addition of a second antifungal agent, success rates were 100%, 83.3% and 92.8%, respectively. There were no differences between the groups in the time to resolution of fungaemia. No patients had immediate local or systemic adverse events and none showed deterioration in renal function. CONCLUSION: ABCD and LamB appear to be effective, safe and well tolerated in premature infants with CBSI and renal dysfunction. Larger trials are needed before routine use can be recommended.

Use of amphotericin B during pregnancy: case report and review.

Unlike the situation with many antimicrobial agents, there is limited experience with the use of amphotericin B during pregnancy. Although reports of fungal infections during pregnancy have been published, few describe fungemia with either Candida or Torulopsis species. We present a case of fungemia due to Torulopsis glabrata that occurred during pregnancy and that was treated with amphotericin B. Drug concentrations were measured in placental tissue, cord serum, and infant serum at delivery. Although the last dose of amphotericin B was administered 4 weeks before delivery, the concentrations in all three specimens were still within the MIC ranges for most strains of Candida albicans and T. glabrata as measured by broth dilution. We speculate that persistent tissue concentrations of amphotericin B most likely contributed to the sustained hypokalemia in the mother and the increased creatinine level in the infant. In the latter case, placental tissue may have served as the reservoir from which amphotericin B was slowly released into fetal circulation.

Inhibition of Candida albicans translocation from the gastrointestinal tract of mice by oral administration of Saccharomyces boulardii.

Microbial translocation is defined as the passage of viable microbes from the gastrointestinal (GI) tract to extraintestinal sites, such as the mesenteric lymph node (MLN), spleen, liver, kidneys, and blood. The ability of orally administered viable Saccharomyces boulardii to inhibit Candida albicans translocation from the GI tract was tested in antibiotic-decontaminated, specific pathogen-free (SPF) mice, which were orally challenged with C. albicans to promote intestinal overgrowth and subsequent translocation of this organism. Oral S. boulardii treatment reduced the incidence of MLN cultures positive for C. albicans but did not decrease the numbers of C. albicans per gram of MLN in these immunocompetent mice. Prednisolone immunosuppression increased translocation of C. albicans to the MLN and allowed translocating C. albicans to spread systemically to the spleen, liver, and kidneys. In these immunosuppressed mice, orally administered S. boulardii decreased both the incidence of C. albicans translocation to the MLN, liver, and kidneys and the number of translocating C. albicans per gram of MLN, spleen, and kidneys.

Differential effects of sepsis and trauma on urinary excretion of polyamines.

Urinary excretion of polyamines increases in patients with trauma and infection. To separate the effect of infection from the general metabolic response to sepsis, we studied 7 patients with sepsis and 13 patients with multiple trauma in the intensive-care unit. Urinary excretion of total and free polyamines, putrescine, spermidine, spermine, and their metabolites N1-acetylspermidine (N1-AcSPD) and N8-acetylspermidine (N8-AcSPD), and energy and nitrogen balance were measured. The patients were randomized to receive either hypocaloric glucose alone or with amino acids for 2 days. The excretion of individual polyamines, except spermine, significantly exceeded normal values in both patient groups; the excretion of total polyamines was 530 and 323% higher than normal in patients with sepsis and trauma, respectively. The excretion of N1-AcSPD and total spermidine was 141 and 74% higher in patients with sepsis than in patients with trauma, respectively (p < 0.05), whereas the excretion of N8-AcSPD was equal in both patient groups. This was also reflected as a significantly increased urinary ratio of N1-AcSPD to N8-AcSPD in septic patients (6.37 +/- 1.61; mean +/- SE) compared with patients after injury (2.69 +/- 0.27, p < 0.01) or a healthy population (1.08 +/- 0.04, p < 0.001). Amino acid infusion had no effect on polyamine excretion. The mean energy balance was -17.0 +/- 1.1 and -19.1 +/- 1.1 kcal.kg-1.day-1, and the mean nitrogen balance was -0.17 +/- 0.03 and -0.15 +/- 0.02 g.kg-1.day-1 in patients with sepsis and trauma, respectively (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of pentoxifylline on tumor necrosis factor production and survival during lethal E. coli sepsis vs. disseminated candidiasis with fungal septic shock.

Lethal circulatory shock during microbial sepsis is thought to be initiated by early molecular events, including production of tumor necrosis factor (TNF) and cytokine-mediated upregulation of neutrophil (PMN) function, irrespective of the causative organism. The phosphodiesterase inhibitor pentoxifylline (PTX) inhibits TNF gene transcription and modulates PMN function, and has been shown to improve outcome in experimental sepsis. We hypothesized that PTX would attenuate gram-negative and fungal septic shock by different mechanisms: reduced TNF production in Escherichia coli (EC) sepsis vs. enhanced PMN-mediated defense during Candida albicans (CA) fungemia. Conscious chronically catheterized rats received PTX (25 mg/kg, i.v.) before i.v. challenge with 10(10) viable EC (serotype 055:B5), 10(9) viable serotype A yeast-phase CA (each the LD100 in < 24 hr in naive rats), or normal sterile saline (NSS), and then PTX posttreatment (6.5 mg/hr x 4.5 hr). Treatment controls received NSS before and after challenge. Serum TNF peaked 1.5 hr after EC infection in NSS-treated animals (1654 +/- 390 U/ml, mean +/- SE), and was significantly reduced by PTX (120 +/- 32 U/ml, P < 0.01), but PTX did not improve 24 hr survival. PTX also aggravated systemic hypotension after EC, and did not modify neutropenia, thrombocytopenia, or microvascular permeability assessed by organ wet/dry weight (W/D) ratios. Peak serum TNF in CA + NSS animals (130 +/- 45 U/ml) was delayed 8 hr compared to EC animals, and were not reduced by PTX (67 +/- 25 U/ml, P = NS). Moreover, PTX did not alter CA-induced mortality, hypothermia, hypotension, neutropenia, increased lung W/D, or interstitial and alveolar hemorrhage. We conclude that PTX-induced suppression of endogenous TNF production does not prevent gram-negative shock in this model, possibly due to impaired TNF-mediated antibacterial host defense. Since fungal septic shock with acute disseminated candidiasis evolves prior to significant increases in circulating TNF, PTX also appears ineffective in its treatment.