Non-contact induction heating and SAAP-148 eliminate persisters within MRSA biofilms mimicking a metal implant infection.

Implant-associated infections are the primary cause of complications following orthopaedic surgery. Due to biofilm and persister formation, current treatments, i.e. surgical debridement followed by antibiotics, often fail. There is an urgent need for alternative strategies to combat such infections. Therefore, the present study investigated the effects of non-contact induction heating (NCIH), the antimicrobial peptide SAAP-148 and combinations thereof on bacterial counts in 7 d mature biofilms and in persister-enriched biofilms of methicillin-resistant Staphylococcus aureus (MRSA) on titanium-aluminium-niobium (TAN) discs. Enrichment of persisters was achieved by daily exposure of mature biofilms to high doses of rifampicin and ciprofloxacin for 3 consecutive days. To heat up the TAN discs, a miniaturised induction heater was built and successfully validated. Using this apparatus, NCIH resulting in surface temperatures up to 85 °C eradicated all the bacteria in immature biofilms but not in mature biofilms, whereas persisters were already eliminated at surface temperatures ≥ 70 °C. SAAP-148 at concentrations > 25.6 µmol/L reduced the persister counts in antibiotics-exposed, mature biofilms. As surface temperatures > 60 °C can have detrimental effects on the surrounding tissues, the maximum temperature of NCIH used in combination with SAAP-148 on persisters was set to 60 °C. Results revealed that this combination was slightly more effective than the peptide or NCIH alone in eliminating biofilm-embedded persisters. NCIH and SAAP-148 can be applied both invasively and non-invasively in various treatment scenarios. Together, combinations of NCIH and SAAP-148 might be a promising treatment strategy to combat metal-implant-associated infections.

The licorice pentacyclic triterpenoid component 18ß-glycyrrhetinic acid enhances the activity of antibiotics against strains of methicillin-resistant Staphylococcus aureus.

This study aimed to identify compounds that enhance the activity of current antibiotics against multidrug-resistant bacteria. Screening of a 350+ compound proprietary small molecules library revealed that the Glycyrrhiza glabra (licorice)-derived triterpenoid 18ß-glycyrrhetinic acid (18ß-GA) potentiated the antibacterial activity of certain antibiotics against Staphylococcus aureus. Here, we evaluated the ability of pentacyclic triterpenoids to potentiate the activity of antibiotics against strains of methicillin-resistant S. aureus (MRSA). Checkerboard assays were used to assess the minimum inhibitory concentration (MIC) of tobramycin and ten pentacyclic triterpenoids against S. aureus. The effect of 18ß-GA on the MIC of different antibiotics against MRSA was also determined in an in vitro airway MRSA infection model. 18ß-GA enhanced the bactericidal activity of the aminoglycosides tobramycin, gentamicin and amikacin, and of polymyxin B against two MRSA strains, reducing the MIC of these antibiotics 32-64-fold [fractional inhibitory concentration index (FICI) of 0.12-0.13]. Other ß-amyrin triterpenoids and α-amyrin triterpenoids did not exert such synergistic effects. 18ß-GA did not enhance the activity of antibiotics from other structural classes against the MRSA strains. In an air-exposed airway epithelial cell culture, 18ß-GA enhanced the bactericidal activity of tobramycin and polymyxin B against the MRSA strain. These data demonstrate the potential of 18ß-GA to synergise with certain types of antibiotics to eliminate strains of MRSA.

Detection of Alpha-Toxin and Other Virulence Factors in Biofilms of Staphylococcus aureus on Polystyrene and a Human Epidermal Model.

BACKGROUND & AIM: The ability of Staphylococcus aureus to successfully colonize (a)biotic surfaces may be explained by biofilm formation and the actions of virulence factors. The aim of the present study was to establish the presence of 52 proteins, including virulence factors such as alpha-toxin, during biofilm formation of five different (methicillin resistant) S. aureus strains on Leiden human epidermal models (LEMs) and polystyrene surfaces (PS) using a competitive Luminex-based assay. RESULTS: All five S. aureus strains formed biofilms on PS, whereas only three out of five strains formed biofilms on LEMs. Out of the 52 tested proteins, six functionally diverse proteins (ClfB, glucosaminidase, IsdA, IsaA, SACOL0688 and nuclease) were detected in biofilms of all strains on both PS and LEMs. At the same time, four toxins (alpha-toxin, gamma-hemolysin B and leukocidins D and E), two immune modulators (formyl peptide receptor-like inhibitory protein and Staphylococcal superantigen-like protein 1), and two other proteins (lipase and LytM) were detectable in biofilms by all five S. aureus strains on LEMs, but not on PS. In contrast, fibronectin-binding protein B (FnbpB) was detectable in biofilms by all S. aureus biofilms on PS, but not on LEMs. These data were largely confirmed by the results from proteomic and transcriptomic analyses and in case of alpha-toxin additionally by GFP-reporter technology. CONCLUSION: Functionally diverse virulence factors of (methicillin-resistant) S. aureus are present during biofilm formation on LEMs and PS. These results could aid in identifying novel targets for future treatment strategies against biofilm-associated infections.

Prevention of Staphylococcus aureus biomaterial-associated infections using a polymer-lipid coating containing the antimicrobial peptide OP-145.

The scarcity of current antibiotic-based strategies to prevent biomaterial-associated infections (BAI) and their risk of resistance development prompted us to develop a novel antimicrobial implant-coating to prevent Staphylococcus aureus-induced BAI. We incorporated the antimicrobial peptide OP-145 into a Polymer-Lipid Encapsulation MatriX (PLEX)-coating to obtain high peptide levels for prolonged periods at the implant-tissue interphase. We first confirmed that OP-145 was highly effective in killing S. aureus and inhibiting biofilm formation in vitro. OP-145 injected along S. aureus-inoculated implants in mice significantly reduced the number of culture-positive implants. OP-145 was released from the PLEX coating in a controlled zero-order kinetic rate after an initial 55%-burst release and displayed bactericidal activity in vitro. In a rabbit intramedullary nail-related infection model, 67% of rabbits with PLEX-OP-145-coated nails had culture-negative nails after 28days compared to 29% of rabbits with uncoated nails. In rabbits with PLEX-OP-145-coated nails, bone and soft tissue samples were culture-negative in 67% and 80%, respectively, whereas all bone samples and 71% of the soft tissue samples of rabbits with uncoated nails were infected. Together, PLEX-OP-145 coatings, of which both compounds have already been found safe in man, can prevent implant colonization and S. aureus-induced BAIs.

Reduced filaggrin expression is accompanied by increased Staphylococcus aureus colonization of epidermal skin models.

BACKGROUND: Atopic dermatitis is an inflammatory skin disease that is characterized by a reduced skin barrier function, reduced filaggrin (FLG) expression as well as increased colonization by Staphylococcus aureus. OBJECTIVE: This study focused on the possible involvement of FLG in epidermal colonization by S. aureus and/or whether it affects the epidermal defence mechanisms, including the expression of antimicrobial peptides (AMPs) and enzymes involved in stratum corneum barrier lipid synthesis. Furthermore, IL-31 has been shown to reduce FLG expression, but its effects on bacterial colonization and on the expression of AMPs and enzymes involved in the barrier lipid synthesis are not known. MATERIAL AND METHODS: We established N/TERT-based epidermal models (NEMs), after FLG knockdown (FLG-KD) and/or cultured with IL-31, that were colonized with S. aureus for 24 h. RESULTS: Both FLG-KD and IL-31 supplementation resulted in significantly increased epidermal S. aureus colonization, as well as in an up-regulation of S. aureus-induced IL-8 expression. IL-31, but not FLG-KD, prevented S. aureus-induced up-regulation of mRNA expression for the AMPs human ß-defensin 2 and -3 and RNAse7, whereas psoriasin expression remained unchanged. Furthermore, the S. aureus colonization induced changes in mRNA expression of ELOVL4 was not affected by FLG-KD, but was blocked by IL-31. Expression of SCD-1 and Gcase mRNA was reduced by IL-31, but not by FLG-KD. CONCLUSION: This study shows that NEMs, with FLG-KD and/or cultured in the presence of IL-31, mimic the skin of patients with atopic dermatitis in several aspects, including enhanced bacterial colonization, increased inflammatory and reduced protective responses.

Humoral immune response as predictor of recurrence in Clostridium difficile infection.

Low serum concentrations of antibodies directed against the toxins TcdA and TcdB have been associated with a higher risk of recurrence of Clostridium difficile infection (CDI) after successful antibiotic treatment. However, there are conflicting reports. Herein, we compared serum levels of antibodies of patients with a single episode of CDI with those of patients who subsequently suffered a recurrence. We used a serum bank from patients who received an experimental whey protein product following successful antibiotic treatment for CDI. We determined levels of IgA and IgG directed against TcdA, TcdB and non-toxin cell surface antigens in serum collected directly and 3 weeks after completing a 10-day course of antibiotic treatment for CDI. We also developed an objective flow cytometry-based assay to determine the proportion of cells exhibiting cytopathic effect after exposure to TcdB. Using this method, we measured the TcdB-neutralizing capacity of sera. We compared the results for patients without a subsequent recurrence with those of patients who suffered a recurrence within 60 days after completing the antibiotic treatment. Advanced age, comorbidity other than immunocompromised state and low serum levels of anti-TcdA and anti-TcdB antibodies were associated with recurrence, whereas serum levels of antibodies directed against cell surface antigens were not. Serum TcdB-neutralizing capacity, which correlated only weakly with serum IgG anti-TcdB, was not significantly associated with recurrence.

Saponin promotes rapid identification and antimicrobial susceptibility profiling of Gram-positive and Gram-negative bacteria in blood cultures with the Vitek 2 system.

The rapid identification and antimicrobial susceptibility testing (AST) of bacteria in clinical blood cultures is crucial to optimise antimicrobial therapy. A previous study involving small sample numbers revealed that the addition of saponin to blood cultures, further referred to as the new method, shortened considerably the turn-around time for the identification and AST of Gram-positive cocci as compared to the current method involving an overnight subculture. Here, we extend previous results and compare the identification and AST of blood cultures containing Gram-negative bacilli by the new and current methods. The identification and AST of 121 Gram-positive and 109 Gram-negative bacteria in clinical monomicrobial blood cultures by the new and current methods and, in the case of Gram-negative bacilli, by direct (no additions) inoculation into an automated system (rapid method) was assessed using the Vitek 2 system. Discrepancies between the results obtained with the different methods were solved by manual methods. The new method correctly identified 88 % of Gram-positive and 98 % of Gram-negative bacteria, and the rapid method correctly identified 94 % of Gram-negative bacteria. The AST for all antimicrobials by the new method were concordant with the current method for 55 % and correct for an additional 9 % of Gram-positive bacteria, and concordant with the current method for 62 % and correct for an additional 21 % of Gram-negative bacilli. The AST by the rapid method was concordant with the current method for 62 % and correct for an additional 12 % of Gram-negative bacilli. Together, saponin-treated monomicrobial blood cultures allow rapid and reliable identification and AST of Gram-positive and Gram-negative bacteria.

Rapid identification and antimicrobial susceptibility profiling of Gram-positive cocci in blood cultures with the Vitek 2 system.

Rapid identification and antimicrobial susceptibility profiling of the bacteria in blood cultures can result in clinical and financial benefits. Addition of saponin to the fluid from blood culture bottles promotes the recovery of the bacteria and thus may shorten the turnaround time of the microbiological analyses. In this study we compared the identification and susceptibility profiles of saponin-treated and untreated (standard method) blood cultures monomicrobial for Gram-positive cocci using Vitek 2. We concordantly identified 49 (89%) of 55 monobacterial cultures using the results with the standard method as reference. Complete categorical agreement between the susceptibility profiles with the new and the standard method was found for 26 (53%) of 49 isolates, while discrepancies were seen for 23 (47%) cultures. E-tests indicated that the new method resulted in a correct susceptibility profile for 8 (35%) of these 23 blood cultures. Therefore, 34 (69%) of 49 cultures showed a concordant/correct susceptibility profile for all antimicrobials with an overall error rate of 2.3%. Thus, addition of saponin to the fluid from blood culture bottles of the Bactec 9240 leads to the rapid (results available >or=12 hours earlier) and reliable identification and susceptibility profiling of Gram-positive cocci in blood cultures with Vitek 2.

Rapid identification and antimicrobial susceptibility testing of Gram-positive cocci in blood cultures by direct inoculation into the BD Phoenix system.

Rapid identification and antimicrobial susceptibility testing (AST) of the causative agent(s) of bloodstream infections are essential for the selection of appropriate antimicrobial therapy. To speed up the identification and AST of the causative agent, the fluid from blood culture bottles of a Bactec 9240 instrument (Becton Dickinson) containing Gram-positive cocci was mixed with saponin. After a 15-min incubation, the bacteria were harvested and transferred to the appropriate panel of a BD Phoenix automated microbiology system (Becton Dickinson) for identification and AST. With this approach (referred to as the direct method), we concordantly/correctly identified 56 (82%) of 68 monomicrobial cultures using the results obtained with the method currently used in our laboratory (current method) as comparator. Two (3%) isolates could not be identified and ten (15%) were misidentified. Complete agreement, concerning clinical susceptibility categories and MIC values, between the AST results determined with the direct method and the current method was found for 32 (55%) of 58 isolates. The E-test indicated that the direct method yielded a correct susceptibility profile for 13 of the remaining 26 blood culture isolates. Therefore, a concordant/correct susceptibility profile (with all antimicrobial agents tested) was obtained for 45 (77%) of 58 cultures. The overall error rate amounted to 1.9%, with the majority (1.3%) of errors being minor. Importantly, the results obtained with the direct method were available 12-24h earlier than those obtained with the current method.

Maggot secretions suppress pro-inflammatory responses of human monocytes through elevation of cyclic AMP.

AIMS/HYPOTHESIS: Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As monocytes may contribute to the excessive inflammatory responses in such wounds, this study focussed on the effects of maggot secretions on the pro-inflammatory activities of these cells. METHODS: Freshly isolated monocytes were incubated with a range of secretions for 1 h and then stimulated with lipopolysaccharides (range 0-100 ng/ml) or lipoteichoic acid (range 0-5 microg/ml) for 18 h. The expression of cell surface molecules, cytokine and chemokine levels in culture supernatants, cell viability, chemotaxis, and phagocytosis and killing of Staphylococcus aureus were measured. RESULTS: Maggot secretions dose-dependently inhibited production of the pro-inflammatory cytokines TNF-alpha, IL-12p40 and macrophage migration inhibitory factor by lipopolysaccharides- and lipoteichoic acid-stimulated monocytes, while enhancing production of the anti-inflammatory cytokine IL-10. Expression of cell surface receptors involved in pathogen recognition remained unaffected by secretions. In addition, maggot secretions altered the chemokine profile of monocytes by downregulating macrophage inflammatory protein-1beta and upregulating monocyte chemoattractant protein-1 and IL-8. Nevertheless, chemotactic responses of monocytes were inhibited by secretions. Furthermore, maggot secretions did not affect phagocytosis and intracellular killing of S. aureus by human monocytes. Finally, secretions induced a transient rise in the intracellular cyclic AMP concentration in monocytes and Rp-cyclic AMPS inhibited the effects of secretions. CONCLUSIONS/INTERPRETATION: Maggot secretions inhibit the pro-inflammatory responses of human monocytes through a cyclic AMP-dependent mechanism. Regulation of the inflammatory processes by maggots contributes to their beneficial effects on chronic wounds.

IL-10 promotor haplotypes associated with susceptibility to and severity of bacterial corneal ulcers.

Interleukin-10 plays an important role in modulating inflammation and antimicrobial defences. In animal models for bacterial corneal ulcers, high IL-10 levels were associated with a better clinical outcome. We investigated whether IL-10 promotor haplotypes, known to determine IL-10 expression in vitro, are associated with susceptibility to and/or clinical outcome of bacterial corneal ulcers in patients. IL-10 promotor polymorphisms C-819T, G-1082A, A-2763C, and A-2849G for 83 patients with bacterial corneal ulcers and 115 healthy controls were determined by restriction fragment length PCR analysis. For 63 patients and all healthy controls the most frequently occurring IL-10 promotor haplotypes were inferred from these data using the program SNPHAP. A significant underrepresentation of the A-2849A genotype was observed in patients as compared to healthy controls. Both the -2763A allele and the IL-10.1 promotor haplotype were associated with a poor clinical outcome, whereas a favourable clinical outcome was seen in patients carrying the IL-10.2 promotor haplotype. Together, IL-10 promotor haplotypes associated with low IL-10 levels seem to protect against the onset of bacterial corneal ulcers. Once a corneal ulcer has developed, patients carrying IL-10 haplotypes associated with a high IL-10 expression may have a favourable outcome.

Human antimicrobial peptides' antifungal activity against Aspergillus fumigatus.

In light of the need for new antifungals, we compared the in vitro antifungal activity of two peptides derived from human lactoferrin (hLF), i.e., hLF(1-11) and hLF(21-31), two analogs of histatin 5, further referred to as dhvar4 and dhvar5, and two ubiquicidin (UBI)-derived peptides, i.e., UBI 18-35 and UBI 29-41, with that of amphotericin B against Aspergillus fumigatus hyphae using the MTT assay. The results revealed a dose-dependent antifungal activity for all peptides, with dhvar5 being the most potent peptide. In addition, hLF(1-11), dhvar5, and UBI 18-35 were effective against A. fumigatus conidia. Furthermore, hLF(1-11) did not lyze human erythrocytes, whereas dhvar5 (>or=16 microM) and UBI 18-35 (>or=20 microM) were hemolytic. Based on these in vitro results and their effectiveness against infections in mice, we concluded that hLF(1-11) and dhvar5 are promising candidates for the development of new agents against A. fumigatus infections.

Lactoferrin Glu561Asp polymorphism is associated with susceptibility to herpes simplex keratitis.

Lactoferrin plays an important role in the defense against infections, including herpes simplex virus (HSV) keratitis. We studied the impact of three single nucleotide polymorphisms in the human lactoferrin gene on the susceptibility to HSV infections of the eye and the severity of such infections. Lactoferrin gene polymorphisms were determined by PCR combined with restriction fragment length analysis in 105 HSV keratitis patients and 145 control subjects. Bilateral tear samples were harvested from 50 patients and 40 healthy controls and tear lactoferrin concentrations were determined by ELISA. Patients' records were used to acquire information about the severity of the HSV keratitis. The frequencies of the Glu561Asp polymorphism, but not those of the Ala11Thr and Lys29Arg polymorphisms, differed significantly between patients and control subjects with an under-representation of the Asp561 allele in the patient group. Furthermore, the values for best corrected visual acuity, frequency of recurrences since onset, and average duration of clinical episodes did not differ among patients with various lactoferrin genotypes. In addition, tear lactoferrin concentrations were the same in patients with HSV keratitis and healthy controls and also did not differ among patients with various lactoferrin genotypes. Lactoferrin Glu561Asp polymorphism is associated with the susceptibility to HSV keratitis with a protective role for lactoferrin variants comprising Asp561. However, no beneficial effects of this lactoferrin variant on the clinical outcome of ocular HSV keratitis were noted.

Effects of monomethylfumarate on dendritic cell differentiation.

BACKGROUND: Fumaric acid esters (FAE) are effective against psoriasis vulgaris and monomethylfumarate (MMF) is believed to be the most bioactive metabolite of this medication. Earlier we found that the beneficial effects of FAE medication are accompanied by a downregulation of type 1 cytokine production by T-helper (Th) lymphocytes, which are important as they maintain a type 1 cytokine [interferon (IFN)-gamma, interleukin (IL)-2] environment in the skin lesions of psoriasis vulgaris patients and once maximal beneficial effects are obtained type 2 cytokine production is also decreased. In vitro MMF selectively induced type 2 cytokine production by primed Th lymphocytes, whereas type 1 cytokine production by and profileration of T lymphocytes were unaffected. OBJECTIVES: As dendritic cells (DCs) present in these skin lesions play a key role in the activation of Th lymphocytes, we investigated the effects of MMF on monocyte-derived DC differentiation. METHODS: Monocytes were differentiated into immature (i) DCs by cytokines with or without MMF. To establish whether these cells were differentiated into iDCs, we analysed the expression of cell surface molecules on these cells and the capacity to capture antigens using flow cytometry. Next, we determined whether these MMF-incubated (MMF-)iDCs could be matured by lipopolysaccharide (LPS) and whether MMF affected this responsiveness as well. For this purpose we measured cytokine production by these LPS-stimulated cells (MMF-DCs) using enzyme-linked immunosorbent assays as well as their ability to activate naive Th lymphocytes. RESULTS: The presence of MMF during the differentiation of monocytes into iDCs resulted in cells that retained low levels of CD14 and hardly expressed CD1a. Upon maturation, these MMF-iDCs upregulated CD83 and costimulatory molecules and HLA-DR on their surface, indicating that these cells respond to LPS, albeit less than control iDCs. In addition, in response to LPS, MMF-iDCs did not decrease the capacity to capture antigens when compared with control iDCs. MMF-DCs hardly produced IL-12p70 and IL-10 and low levels of tumour necrosis factor (TNF)-alpha, whereas IL-8 produced by MMF-DCs and control DCs did not differ. Moreover, MMF-DCs were less able to induce IFN-gamma production by naive Th lymphocytes compared with control DCs. The production of IL-4 and IL-10 by naive Th lymphocytes cocultured with MMF-DCs did not differ from that by T cells cocultured with control DCs. CONCLUSIONS: MMF inhibited the monocyte-derived DC differentiation resulting in cells that cannot be appropriately matured to DCs. Consequently, these MMF-DCs are less effective than control DCs in stimulating type 1 cytokine, but not type 2 cytokine production, in Th lymphocytes. This general immunomodulatory effect may in part explain the beneficial effects of FAE therapy in psoriasis.

Detection of fungal infections using radiolabeled antifungal agents.

The outcome of antifungal therapy depends on the progression of the infection at the start of therapy. Unfortunately, most patients are diagnosed once the fungal infection has progressed considerably as a result of the non-specific clinical signs of fungal infections in immunocompromised patients and the poor sensitivity of current mycological diagnostic tests. This review will highlight current fungal diagnostic techniques and will focus on scintigraphic methods for the specific detection of fungal infections in mice. For this purpose, antifungal components (e.g. fluconazole and antifungal peptides) are radiolabeled e.g. with technetium-99m ((99m)Tc) and their in vivo distribution is monitored in infected mice. It has been demonstrated that (99m)Tc-fluconazole is an excellent tracer to detect Candida albicans infections in mice as it distinguishes these infections from bacterial infections and sterile inflammations. However, this radiopharmaceutical only poorly detects infections with Aspergillus fumigatus in mice. (99m)Tc-peptides derived from antifungal peptides/proteins, such as human ubiquicidin and lactoferrin, can distinguish C. albicans and A. fumigatus infections from sterile inflammations, but not from bacterial infections, in mice. Furthermore, the efficacy of fluconazole in C. albicans-infected mice could be successfully monitored using (99m)Tc-ubiquicidin. In conclusion, neither (99m)Tc-fluconazole nor the (99m)Tc-peptides tested are optimal tracers for fungal infections. Nonetheless, since early initiation of antifungal therapy for candidemia reduces its high mortality rate, a positive result with (99m)Tc-fluconazole scintigraphy is of clinical relevance. Finally, the possibility that other (radiolabeled) antifungal agents, e.g. voriconazole, caspofungin, antifungal plant or insect defensins, can be useful for detection of fungal infections should be considered.

Plasma secretory leukocyte protease inhibitor in febrile patients.

OBJECTIVES: Secretory leukocyte protease inhibitor (SLPI) forms an integral part of the lung's defence, by its antimicrobial activity and by its ability to neutralize serine proteases that are released by granulocytes into the inflammatory exudate. Here, we investigate in febrile patients admitted to hospital whether plasma SLPI can serve as a marker of lung infection. METHODS: We prospectively determined the SLPI concentration in 152 febrile patients (median 73 [inter-quantile range (IQR): 58-82] year; 50% male) admitted to hospital because of infection of the airways (n = 44) or pneumonia (n = 108; i.e. consolidation on chest X-ray), and in 48 febrile patients (78 [IQR: 71-85] year; 52% male) admitted because of pyelonephritis, as well as afebrile age-matched controls (n = 38). In addition, erythrocyte sedimentation rate (ESR), peripheral blood leukocytes, plasma TNFalpha and IL-10, and parameters of the APACHE-II score were determined on admission. RESULTS: In febrile patients, SLPI was significantly increased (P < 0.001) compared with afebrile controls (63 [IQR: 50-76] ng/mL): plasma SLPI (113 [IQR: 83-176] ng/mL) was highest (P < 0.005) in patients with pneumonia compared with other groups (88 [IQR: 70-118] ng/mL). Only in patients with pneumonia, bacteremia significantly increased (P < 0.01) SLPI concentrations. Using a radiological classification of pulmonary infiltrates based on their size, it was found that plasma SLPI was proportional to the extent of lung tissue involved: the median concentration increased from 95 [IQR: 74-139] ng/mL in unilateral segmental consolidation up to 271 [IQR: 180-460] ng/mL in bilateral lobar consolidations. In a multivariate analysis, the association between SLPI and extent of consolidation was about two-fold stronger than, and independent of, the association between SLPI and erythrocyte sedimentation rate, TNFalpha, and parameters of the composite APACHE-II score, such as heart rate and blood pressure, that reflect severity of illness. CONCLUSION: SLPI is an indicator of the presence and extent of pneumonia in febrile patients admitted to hospital. In patients with an infection with its primary source located outside the lung, plasma SLPI likely reflects the mucosal response to circulating inflammatory mediators reflecting severity of illness.

Beneficial effects of fumarate therapy in psoriasis vulgaris patients coincide with downregulation of type 1 cytokines.

BACKGROUND: Fumarates have been shown to be effective in psoriasis vulgaris. OBJECTIVES: To find out whether successful therapy is associated with modulation of cytokines. METHODS: We determined interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 secretion capacities of peripheral blood mononuclear cells (PBMC) after phytohaemagglutinin stimulation, and IL-12p70 and IL-10 secretion capacities of PBMC after endotoxin stimulation in psoriasis vulgaris patients during treatment with fumarates. In a cohort study, 12 patients (five men, median age 50 years; seven women, median age 46 years) with psoriasis vulgaris were followed during 24 months of fumarate treatment. In addition, we followed 14 healthy controls (six men, median age 31 years; eight women, median age 29 years) without skin diseases during 12 months to investigate possible changes in the cytokine secretion capacity of PBMC as a result of seasonal changes. Disease activity in patients was determined by Psoriasis Area and Severity Index (PASI) score. Blood was collected for measurement by enzyme-linked immunosorbent assay of cytokine levels after stimulation of PBMC. RESULTS: Within 6 months of fumarate treatment, the mean +/- SD PASI score had decreased to 22 +/- 9% of its initial value. These beneficial effects coincided with lymphocytopenia and a significant (P < 0.05) downregulation of IFN-gamma expression by circulating blood cells, followed by a significant downregulation of IL-4 expression. Notably, production of the cytokine synthesis inhibitor IL-10 by PBMC was unchanged. CONCLUSIONS: The beneficial effects of fumarates may be attributed to their downregulatory action on type 1 cytokines.

99mTc-antimicrobial peptides: promising candidates for infection imaging.

This review presents the state of the art of imaging of bacterial and fungal infections in laboratory animals using antimicrobial peptides labelled with technetium-99m ((99m)Tc). The mechanistic basis of this approach is that these peptides accumulate at sites of infection, but not in sterile inflammatory lesions, because of their preferential binding to bacteria and fungi over mammalian cells. For practical reasons, such as production of large amounts of peptides under good laboratory practice conditions and favourable pharmacokinetics, synthetic peptides representing such binding domains of natural antimicrobial peptides are preferred. On the basis of their preferential in vitro and in vivo binding to microorganisms over human cells, fast and easy penetration into the target area, and rapid clearance from the circulation via the urinary tract, various (99m)Tc-antimicrobial peptides were identified. Next, it was determined whether these radiopharmaceuticals distinguish infectious foci from sites of sterile inflammation. Further experiments with (99m)Tc-ubiquicidin-derived peptides in infected laboratory animals have revealed that the radioactivity at the infectious site correlated well with the number of viable bacteria present, indicating that these (99m)Tc-labelled peptides may enable the monitoring of the efficacy of antimicrobial therapy. Together, (99m)Tc-labelled synthetic peptides derived from human ubiquicidin are promising candidates for imaging of bacterial and fungal infections in nuclear medicine.