Pharmacodynamic and immunological interactions of amphotericin B formulations and voriconazole with human neutrophils against mature Scedosporium apiospermum and Fusarium spp. biofilms.

BACKGROUND: Mould infections caused by Scedosporium apiospermum and Fusarium solani species complex (FSSC) biofilms are rising among immunocompromised and immunocompetent patients. Little is known about the immunomodulatory effects of antifungal agents against these moulds. We examined the effects of deoxycholate and liposomal amphotericin B (DAmB, LAmB) and voriconazole on antifungal activities and immune responses of neutrophils (PMNs) against mature biofilms compared with their planktonic counterparts. METHODS: Antifungal activity of human PMNs exposed to mature biofilms and planktonic cells for 24 h was determined at effector-to-target ratios of 2:1 and 5:1, alone or combined with DAmB, LAmB and voriconazole, assessed as fungal damage by XTT assay. Cytokine production was evaluated by multiplex ELISA, following PMN stimulation with biofilms in the presence/absence of each drug. RESULTS: All drugs showed additive or synergistic effects with PMNs against S. apiospermum at 0.03-32 mg/L. They showed antagonism primarily against FSSC at 0.06-64 mg/L. Increased IL-8 was produced by PMNs exposed to S. apiospermum biofilms plus DAmB or voriconazole compared with PMNs exposed to biofilms alone (P < 0.01). During combined exposure, IL-1ß was increased, an effect only counteracted by increased levels of IL-10 caused by DAmB (P < 0.01). LAmB and voriconazole caused similar IL-10 levels with those released by biofilm-exposed PMNs. CONCLUSIONS: The synergistic, additive or antagonistic effects of DAmB, LAmB or voriconazole on biofilm-exposed PMNs are organism-specific, with FSSC exhibiting greater resilience than S. apiospermum to antifungals. Biofilms of both moulds caused dampened immune responses. The drug-mediated immunomodulating effect on PMNs, evidenced by IL-1ß, enhanced host protective functions.

Paediatric cutaneous mucormycosis: A case report and review of the literature.

BACKGROUND: Mucormycosis has emerged as an increasingly important fungal disease for immunocompromised children and neonates, with the cutaneous form being one of its most common presentations. METHODS: We present a cutaneous mucormycosis case in a 10-year-old girl and analyse reports of single cases and case series of cutaneous mucormycosis in ≤16-year-old patients, recorded in PUBMED from 1953 to 2020, for epidemiology, risk factors, diagnostic and therapeutic procedures and outcome. RESULTS: 113 cases were enrolled. Median age was 5 years (Interquartile Range [IQR] 10.9), without gender predominance. Underlying conditions were haematologic malignancies/disorders (25.7%), prematurity (23%), solid organ transplantation (3.5%), diabetes mellitus type 1 (4.4%), immunodeficiency and other diseases (14.2%), and no underlying conditions (29.2%). Inoculation occurred through major trauma (12.4%), including surgery and motor vehicle accidents, catheter sites (27.4%), dressings, patches and probes (11.5%), burns and farm-related accidents (8.8%). Rhizopus spp. was most frequently isolated (43.4%), followed by Lichtheimia corymbifera (9.7%), Saksenaea vasiformis (8%), Mucor and Rhizomucor spp. (5.3% each), other species/combinations (7.2%) and unspecified isolates (21.2%). Surgery was combined with antifungals in 62.8%. Each was performed solely in 27.4% and 6.2%, respectively. Amphotericin B was used in 78% (alone in 55.8% and combined with other antifungals in 22.2%) of the cases. Overall mortality was 26.5%. In regression analysis, prematurity and haematologic malignancies/disorders were associated with increased mortality, whereas combination of antifungals and surgery with improved survival. CONCLUSION: Cutaneous mucormycosis mainly affects premature infants and children with haematologic malignancies/disorders. Outcome is improved when active antifungal therapy and surgery are combined.

Activity of Amphotericin B Formulations and Voriconazole, Alone or in Combination, against Biofilms of Scedosporium and Fusarium spp.

Scedosporium and Fusarium species are emerging opportunistic pathogens, causing invasive fungal diseases in humans, particularly in immunocompromised patients. Biofilm-related infections are associated with increased morbidity and mortality. Here, we assessed the ability of Scedosporium apiospermum and Fusarium solani species complex (FSSC) isolates to form biofilms and evaluated the efficacy of deoxycholate amphotericin B (D-AMB), liposomal amphotericin B (L-AMB), and voriconazole (VRC), alone or in combination, against mature biofilms. Biofilm formation was assessed by safranin staining and spectrophotometric measurement of optical density. Planktonic and biofilm damage was assessed by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt] reduction assay. Planktonic cell and biofilm MIC50s were determined as the minimum concentrations that caused ≥50% fungal damage compared to untreated controls. The combined activity of L-AMB (0.5 to 32 mg/liter) and VRC (0.125 to 64 mg/liter) against biofilms was determined by the checkerboard microdilution method and analyzed by the Bliss independence model. Biofilm MIC50s of D-AMB and L-AMB against S. apiospermum isolates were 1 and 2 mg/liter and against FSSC isolates were 0.5 and 1 mg/liter, respectively. Biofilm MIC50s of VRC against S. apiospermum and FSSC were 32 mg/liter and >256 mg/liter, respectively. Synergistic effects were observed at 2 to 4 mg/liter of L-AMB combined with 4 to 16 mg/liter of VRC against S. apiospermum biofilms (mean ΔE ± standard error, 17% ± 3.7%). Antagonistic interactions were found at 0.5 to 4 mg/liter of L-AMB combined with 0.125 to 16 mg/liter of VRC against FSSC isolates, at -28% ± 2%. D-AMB and L-AMB were more efficacious against S. apiospermum and FSSC biofilms than VRC.

Population Pharmacokinetics and Outcomes of Critically Ill Pediatric Patients Treated with Intravenous Colistin at Higher Than Recommended Doses.

Limited pharmacokinetic (PK) data suggest that currently recommended pediatric dosages of colistimethate sodium (CMS) by the Food and Drug Administration and European Medicines Agency may lead to suboptimal exposure, resulting in plasma colistin concentrations that are frequently <2 mg/liter. We conducted a population PK study in 17 critically ill patients 3 months to 13.75 years (median, 3.3 years) old who received CMS for infections caused by carbapenem-resistant Gram-negative bacteria. CMS was dosed at 200,000 IU/kg/day (6.6 mg colistin base activity [CBA]/kg/day; 6 patients), 300,000 IU/kg/day (9.9 mg CBA/kg/day; 10 patients), and 350,000 IU/kg/day (11.6 mg CBA/kg/day; 1 patient). Plasma colistin concentrations were determined using ultraperformance liquid chromatography combined with electrospray ionization-tandem mass spectrometry. Colistin PK was described by a one-compartment disposition model, including creatinine clearance, body weight, and the presence or absence of systemic inflammatory response syndrome (SIRS) as covariates (P < 0.05 for each). The average colistin plasma steady-state concentration (Css,avg) ranged from 1.11 to 8.47 mg/liter (median, 2.92 mg/liter). Ten patients had Css,avg of ≥2 mg/liter. The presence of SIRS was associated with decreased apparent clearance of colistin (47.8% of that without SIRS). The relationship between the number of milligrams of CBA per day needed to achieve each 1 mg/liter of plasma colistin Css,avg and creatinine clearance (in milliliters per minute) was described by linear regression with different slopes for patients with and without SIRS. Nephrotoxicity, probably unrelated to colistin, was observed in one patient. In conclusion, administration of CMS at the above doses improved exposure and was well tolerated. Apparent clearance of colistin was influenced by creatinine clearance and the presence or absence of SIRS.

Dose-Dependent Synergistic Interactions of Colistin with Rifampin, Meropenem, and Tigecycline against Carbapenem-Resistant Klebsiella pneumoniae Biofilms.

Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) can cause biofilm-related bloodstream infections associated with significant morbidity and mortality worldwide. We investigated the bactericidal activities of colistin (CST), rifampin (RIF), meropenem (MEM), gentamicin (GEN), and tigecycline (TGC) alone and that of CST in combination with RIF, MEM, GEN, or TGC against CR-Kp mature biofilms. Twenty CR-Kp blood isolates were derived from an equal number of bloodstream infections in adult patients. Biofilm formation was assessed by staining with 0.4% crystal violet and measuring the optical density spectrophotometrically at 545 nm. Biofilm damage was measured as the percent reduction of metabolic activity by an XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt] assay. The MIC50 for biofilms was determined as the minimum concentration that caused ≥50% bacterial damage compared to that for untreated controls. Antibacterial drug interactions were analyzed by the Bliss independence model. Four of the 20 CR-Kp isolates were biofilm producers. Biofilm MIC50s of CST, RIF, MEM, GEN, and TGC for these isolates were 64, 8, >256, 128, and 8 mg/liter, respectively. Synergistic interactions were observed at 32 to 64 mg/liter of CST combined with 0.25 to 4 mg/liter of RIF, at 32 mg/liter of CST combined with 0.007 to 0.25 mg/liter of MEM, and at 16 to 32 mg/liter of CST combined with 16 to 64 mg/liter of TGC. The synergy was highest for CST plus RIF, with a mean ΔE ± standard error (SE) of 49.87% ± 9.22%, compared to 29.52% ± 4.97% for CST plus MEM (P < 0.001) and 32.44% ± 6.49% for CST plus TGC (P < 0.001). Indifferent results were exhibited by CST plus GEN. None of the combinations exhibited antagonism. These drug interaction findings, especially those for CST with RIF, may be of importance in the treatment of biofilm-related CR-Kp infections.

Polyclonal predominance of concurrently producing OXA-23 and OXA-58 carbapenem-resistant Acinetobacter baumannii strains in a pediatric intensive care unit.

We report a predominance (64.7%) of polyclonal carbapenem-resistant Acinetobacter baumannii (CRAB) strains concurrently producing OXA-23 and OXA-58 carbapenemases in a pediatric intensive care unit in an endemic area. This is the first report of emergence of such double-OXA CRAB strains in a single unit worldwide.

Pharmacokinetics of Daptomycin in Critically Ill Pediatric Patients.

The pharmacokinetics of daptomycin (10 mg/kg once daily) was studied in 4 critically ill pediatric patients aged 8 to 14 yrs. The area under the concentration-time curve from time zero to infinity (AUC0-∞) of plasma concentrations on day 1 ranged between 123.8 to 663.9 µg · h/ml, with lower values observed in septic and burn patients; clearance ranged from 15.1 to 80.7 ml/h/kg. Higher-than-recommended doses of daptomycin may be needed in septic children to ensure optimal drug exposure. Interpatient variability may suggest a role for therapeutic drug monitoring.

Molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa in an endemic area: comparison with global data.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is an endemic problem in certain countries including Greece. CRPA and multidrug-resistant P. aeruginosa (MDRPA) firstly emerged in our region during the 80s, right after the launch of imipenem and meropenem as therapeutic agents against P. aeruginosa infections. The role of outer membrane protein (Opr) inactivation has been known to contribute to imipenem resistance since many years, while efflux overexpression systems have been mainly associated with meropenem resistance. Among carbapenemases, metallo-ß-lactamases (MBL) and mostly Verona integron-mediated (VIM) MBL's have played the most crucial role in CRPA emergence. VIM-2 and VIM-4 producing CRPA, usually belonging to clonal complexes (CC) 111 and 235 respectively, have most frequently been isolated. BlaVIM-2 and blaVIM-4 are usually associated with a class 1 integron. VIM-17 also has appeared in Greece. On the other hand, other VIM subtypes detected in a global level, such as VIM-3, VIM-5, VIM-6, VIM-7, VIM-11, VIM-14, VIM-15, VIM-16 and VIM-18 have not yet emerged in Greece. However, new VIM subtypes will probably emerge in the future. In addition, MBL carbapenemases other than VIM, detected worldwide have not yet appeared. A single CRPA isolate producing KPC has emerged in our region several years ago. The study of the molecular basis of Opr deficiency and efflux overexpression remains a challenge for the future. In this article, we review the molecular epidemiology of CRPA in an endemic area, compared to global data.

Epidemiological surveillance of multidrug-resistant gram-negative bacteria in a solid organ transplantation department.

BACKGROUND: We assessed the impact of intensified infection control measures (ICM) on colonization and infection caused by carbapenem-resistant (CR) Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii in a solid organ transplantation (SOT) department. METHODS: A quasi-experimental methodology was followed. The study was divided into three periods: pre-intervention, intervention with implementation of an ICM bundle including active surveillance program (ASP) and gradually enhanced measures, and post-ASP without ASP. The bundle included active surveillance cultures, contact precautions, hand hygiene, education of health care workers (HCWs), monitoring of compliance, and environmental cleaning. Incidence of colonization and infection caused by CR gram-negative bacteria was recorded. Molecular analysis of CR bacteria was performed for a certain period. RESULTS: During the intervention, incidence of colonization reduced from 19% to 9% (P<.001). The compliance of HCWs with contact precautions and hand hygiene also improved. Monthly incidence of infections caused by these CR bacteria increased from 2.8 to 6.9/1000 bed-days (P<.001). However, this increase did not have such a strong trend after the intervention. Most K. pneumoniae isolates, the commonest pathogen, carried the blaKPC gene. Colonization and infection rates by CR K. pneumoniae, P. aeruginosa, and A. baumannii were high among SOT recipients. CONCLUSION: In settings where CR gram-negative bacteria are endemic, colonization and infection rates by these bacteria are high among SOT recipients. Implementation of enhanced ICM in all related units of a hospital, although challenging, reduces colonization rates by CR gram-negative bacteria.

Comparison of cotrimoxazole vs. second-generation cephalosporins for prevention of urinary tract infections in children.

BACKGROUND: Antimicrobial prophylaxis is recommended for the prevention of urinary tract infections (UTI) in high-risk children. However, there is growing concern about the use of ß-lactams as prophylaxis and subsequent development of antibiotic resistance. METHODS: In this prospective, randomized, crossover controlled trial we compared cotrimoxazole (SXT) and second-generation cephalosporins (2GC) as UTI prophylaxis in children ranging in age from 1 to 60 months. Eligible patients were 1:1 randomized to receive either SXT or 2GC for the initial 6-month period (1 course), then switched to the other antimicrobial agent class for the subsequent course, with switching continuing after each course until the end of the study. Urethral orifice cultures (UOCs) were obtained at the time of switching antimicrobial prophylaxis. RESULTS: Among 97 children (mean age 13.6 months) on prophylaxis, breakthrough UTIs occurred during 13.3 % (10/75) of SXT courses and 10.3 % (8/78) of 2GC courses (p = 0.62). 2GC failed earlier than SXT (mean ± standard error: 0.81 ± 0.1 vs. 2.37 ± 0.36 months, respectively; p = 0.028). Pseudomonas aeruginosa and Enterococcus spp. were more frequently isolated after 2GC courses than after SXT courses [22.6 vs. 4.8 % (p = 0.02) and 20.7 vs. 4.8 % (p = 0.035), respectively]. Prophylaxis with 2GC significantly increased resistance to both 2GC and SXT, while SXT prophylaxis did not affect susceptibility to 2GC. CONCLUSIONS: While SXT and 2GC appear to be equally efficacious as UTI prophylaxis in children, the latter exert a broader effect on patients' flora and development of bacterial resistance, suggesting that SXT may be more appropriate for UTI prophylaxis than 2GC.

Differential effects of antifungal agents on expression of genes related to formation of Candida albicans biofilms.

The purpose of this study was to analyse specific molecular mechanisms involved in the intrinsic resistance of C. albicans biofilms to antifungals. We investigated the transcriptional profile of three genes (BGL2, SUN41, ECE1) involved in Candida cell wall formation in response to voriconazole or anidulafungin after the production of intermediate and mature biofilms. C. albicans M61, a well-documented biofilm producer strain, was used for the development of intermediate (12 h and 18 h) and completely mature biofilms (48 h). After exposure of cells from each biofilm growth mode to voriconazole (128 and 512 mg l(-1)) or anidulafungin (0.25 and 1 mg l(-1)) for 12-24 h, total RNA samples extracted from biofilm cells were analysed by RT-PCR. The voriconazole and anidulafungin biofilm MIC was 512 and 0.5 mg l(-1) respectively. Anidulafungin caused significant up-regulation of SUN41 (3.7-9.3-fold) and BGL2 (2.2-2.8 fold) in intermediately mature biofilms; whereas, voriconazole increased gene expression in completely mature biofilms (SUN41 2.3-fold, BGL2 2.1-fold). Gene expression was primarily down-regulated by voriconazole in intermediately, but not completely mature biofilms. Both antifungals caused down-regulation of ECE1 in intermediately mature biofilms.

Nosocomial bloodstream infections in neurosurgery: a 10-year analysis in a center with high antimicrobial drug-resistance prevalence.

BACKGROUND: Data on nosocomial bloodstream infections (NBSI) in neurosurgery is limited. This study aimed to analyze the epidemiology, microbiology, outcome, and risk factors for death in neurosurgical patients with NBSI in a multidrug resistant setting. METHODS: Neurosurgical patients with a confirmed NBSI within the period 2003-2012 were retrospectively analyzed. NBSI was diagnosed when a pathogen was isolated from a blood sample obtained after the first 48 h of hospitalization. Patients' demographic, clinical, and microbiological data were recorded and analyzed using univariate and multivariate analysis. RESULTS: A total of 236 patients with NBSI were identified and 378 isolates were recovered from blood cultures. Incidence of NBSI was 4.3 infections/1000 bed-days. Gram-negative bacteria slightly predominated (54.5 %). The commonest bacteria were coagulase-negative staphylococci (CoNS, 26 %), Klebsiella pneumoniae (15.3 %), Pseudomonas aeruginosa (14.8 %), and Acinetobacter baumannii (13.2 %). Carbapenem resistance was found in 90 % of A. baumannii, in 66 % of P. aeruginosa, and in 22 % (2003-2007) to 77 % (2008-2012) of K. pneumoniae isolates (p < 0.05). Most CoNS and Staphylococcus aureus isolates (94 and 80 %, respectively) were methicillin-resistant. All Gram-negative isolates were sensitive to colistin and all Gram-positive isolates were sensitive to vancomycin and linezolid. Antimicrobial consumption decreased after 2007 (p < 0.05). Overall mortality was 50.4 %. In multivariate analysis, advanced age and stay in an Intermediate Care Unit (IMCU) were independent risk factors for in-hospital mortality (p < 0.05). CONCLUSIONS: Overall, high incidence of NBSI and considerable resistance of Gram-positive and particularly Gram-negative bacteria were noted in neurosurgical patients. Mortality was high with advanced age and stay in IMCU being the most important death-related factors.

Antipseudomonal agents exhibit differential pharmacodynamic interactions with human polymorphonuclear leukocytes against established biofilms of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is the most common pathogen infecting the lower respiratory tract of cystic fibrosis (CF) patients, where it forms tracheobronchial biofilms. Pseudomonas biofilms are refractory to antibacterials and to phagocytic cells with innate immunity, leading to refractory infection. Little is known about the interaction between antipseudomonal agents and phagocytic cells in eradication of P. aeruginosa biofilms. Herein, we investigated the capacity of three antipseudomonal agents, amikacin (AMK), ceftazidime (CAZ), and ciprofloxacin (CIP), to interact with human polymorphonuclear leukocytes (PMNs) against biofilms and planktonic cells of P. aeruginosa isolates recovered from sputa of CF patients. Three of the isolates were resistant and three were susceptible to each of these antibiotics. The concentrations studied (2, 8, and 32 mg/liter) were subinhibitory for biofilms of resistant isolates, whereas for biofilms of susceptible isolates, they ranged between sub-MIC and 2 × MIC values. The activity of each antibiotic alone or in combination with human PMNs against 48-h mature biofilms or planktonic cells was determined by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. All combinations of AMK with PMNs resulted in synergistic or additive effects against planktonic cells and biofilms of P. aeruginosa isolates compared to each component alone. More than 75% of CAZ combinations exhibited additive interactions against biofilms of P. aeruginosa isolates, whereas CIP had mostly antagonistic interaction or no interaction with PMNs against biofilms of P. aeruginosa. Our findings demonstrate a greater positive interaction between AMK with PMNs than that observed for CAZ and especially CIP against isolates of P. aeruginosa from the respiratory tract of CF patients.

In vitro interactions between farnesol and fluconazole, amphotericin B or micafungin against Candida albicans biofilms.

OBJECTIVES: Biofilm formation by Candida albicans poses an important therapeutic challenge in human diseases. Typically, conventional antifungal agents encounter difficulty in treating and fully eradicating biofilm-related infections. Novel therapeutic approaches are needed to treat recalcitrant Candida biofilms. Farnesol is a quorum-sensing molecule, which induces apoptosis, inhibits Ras protein pathways and profoundly affects the morphogenesis of C. albicans. We therefore investigated the interactions between farnesol and different classes of antifungal agents. METHODS: The combined antifungal effects of triazoles (fluconazole), polyenes (amphotericin B) and echinocandins (micafungin) with farnesol against C. albicans biofilms were assessed in vitro. Antifungal activity was determined by the XTT metabolic assay and confocal microscopy. The nature and the intensity of the interactions were assessed using the Loewe additivity model [fractional inhibitory concentration (FIC) index] and the Bliss independence (BI) model. RESULTS: Significant synergy was found between each of the three antifungal agents and farnesol, while antagonism was not observed for any of the combinations tested. The greatest synergistic effect was found with the farnesol/micafungin combination, for which the BI-based model showed the observed effects as being 39%-52% higher than expected if the drugs had been acting independently. The FIC indices ranged from 0.49 to 0.79, indicating synergism for farnesol/micafungin and farnesol/fluconazole and no interaction for farnesol/amphotericin B. Structural changes in the biofilm correlated well with the efficacies of these combinations. The maximum combined effect was dependent on the farnesol concentration for micafungin and amphotericin B. CONCLUSIONS: Farnesol exerts a synergistic or additive interaction with micafungin, fluconazole and amphotericin B against C. albicans biofilms, thus warranting further in vivo study.

Successful management of an outbreak due to carbapenem-resistant Acinetobacter baumannii in a neonatal intensive care unit.

UNLABELLED: The investigation and successful management of a monoclonal Acinetobacter baumannii outbreak in a neonatal intensive care unit are described. Upon the first clustered carbapenem-resistant A. baumannii (CRAB) infections, a bundle of actions were taken, including enhanced infection control, active surveillance (weekly stool samples), case-control study, staff education, daily audits and discontinuation of new admissions. Between September and December 2011, eight neonates developed 10 CRAB infections (five blood, four respiratory and one eye). A total of 216 active surveillance cultures were obtained from 96 neonates (43 % had ≥2 samples). During weeks 12, 16 and 17, active surveillance detected 3, 1 and 2 new CRAB acquisitions, respectively. Prevalence of infections/colonizations decreased, and no event occurred after 20th week. A colonized neonate developed CRAB sepsis and died. All CRAB isolates harboured bla OXA-58 and the intrinsic chromosomal bla OXA-51 carbapenemase genes. CONCLUSION: Active surveillance and enhanced infection control measures effectively contained spread of CRAB clone in the neonatal intensive care unit.

Mannose binding lectin and ficolin-2 polymorphisms are associated with increased risk for bacterial infections in children with B acute lymphoblastic leukemia.

BACKGROUND: We aimed to investigate whether the presence of mannose binding lectin (MBL2), ficolin 2 (FCN2) polymorphisms or the combined deficiency significantly influence the risk and subsequently the frequency of chemotherapy-induced bacterial infections in children with B acute lymphoblastic leukemia (B-ALL). PROCEDURE: MBL2 polymorphisms for exon 1 and FCN2 polymorphisms for promoter regions -986, -602, -557, -64, -4 and exon 8 regions +6,359, +6,424 were determined in children with B-ALL. FCN2 haplotype was determined by gene sequencing. Number and duration of FN episodes as well as number of bacterial infections were recorded during induction chemotherapy. RESULTS: Forty-four children with B-ALL (median age 4.3 years, 65.9% males) suffered from 142 FN episodes and 92 bacterial infections (40.2% Gram positive and 59.8% Gram negative). MBL2 low-risk genotype was found in 59.1%, medium-risk in 31.8% and high-risk in 9%. FCN2 low-risk haplotypes were detected in 38.2%, medium-risk in 44.1% and high-risk in 17.6%. MBL2 genotype and FCN2 haplotype were not associated with increased frequency of FN episodes. MBL2 medium/high-risk genotype and FCN2 medium/high-risk haplotype were associated with prolonged duration of FN (P = 0.007 and P = 0.001, respectively) and increased number of bacterial infections (P = 0.001 and P = 0.002, respectively). The combined MBL2/FCN2 medium/high-risk genotype was associated with an increased number of bacterial infections (P = 0.001). CONCLUSIONS: MBL2 and FCN2 single or combined deficiencies are associated with increased duration of FN episodes as well as increased number of bacterial infections in children with B-ALL suggesting a prognostic role of these genes.

Pathogenesis and host defence against Mucorales: the role of cytokines and interaction with antifungal drugs.

Innate immune response, including macrophages, neutrophils and dendritic cells and their respective receptors, plays an important role in host defences against Mucorales with differential activity against specific fungal species, while adaptive immunity is not the first line of defence. A number of endogenous and exogenous factors, such as cytokines and growth factors as well as certain antifungal agents have been found that they influence innate immune response to these organisms. Used alone or especially in combination have been shown to exert antifungal effects against Mucorales species. These findings suggest novel ways of adjunctive therapy for patients with invasive mucormycosis.

Increased virulence of Cunninghamella bertholletiae in experimental pulmonary mucormycosis: correlation with circulating molecular biomarkers, sporangiospore germination and hyphal metabolism.

Members of the order Mucorales are emerging invasive molds that cause infections in immunocompromised patients. However, little is known about the relation between different species of Mucorales and their virulence in invasive pulmonary mucormycosis. Based upon our earlier epidemiological studies, we hypothesized that Cunninghamella bertholletiae would demonstrate increased virulence. Therefore, we studied the relative virulence of C. bertholletiae (CB), Rhizopus oryzae (RO), R. microsporus (RM), and Mucor circinelloides (MC) in experimental invasive pulmonary mucormycosis in persistently neutropenic rabbits in relation to the fungi in vitro sporangiospore germination rate and hyphal metabolic activity. Rabbits infected with CB demonstrated (1) higher lung weights in comparison to RM (P ≤ 0.05), RO and MC (P ≤ 0.001), (2) pulmonary infarcts in comparison to RO and MC (P ≤ 0.001), (3) tissue fungal burden (CFU/g) vs. MC (P ≤ 0.001), and (4) the lowest survival of 0% (0/18), in comparison to 16% (3/18, P ≤ 0.01) of RM, 81% (21/26) of RO, and 83% (15/18) of MC-infected rabbits (P ≤ 0.001). Serum PCR concentration-time-curve showed the greatest amplitude for CB. Virulence correlated directly with sporangiospore germination rate at 4 h among species, i.e., CB (67-85%) > RM (14-56%) > RO (4-30%) > MC (0%), and hyphal metabolic activity, i.e., CB (1.22-1.51) > MC (0.54-0.64) = RM (0.38-0.41) = RO (0.37-0.59). C. bertholletiae was significantly more virulent in experimental invasive pulmonary mucormycosis than R. microsporus, R. oryzae, and M. circinelloides. In vivo virulence correlated with species-dependent differences of in vitro germination rate and hyphal metabolic activity.