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Biomedical subjects

J F Meis

Publications and source records attributed to J F Meis.

At least 37 records · Page 2Linked to original sources

Prevalence of vancomycin-resistant enterococci in Europe.

The aim of the present study was to determine the prevalence of vancomycin-resistant enterococci (VRE) in Europe. Overall, 49 laboratories in 27 countries collected 4,208 clinical isolates of enterococci. Species identification, susceptibility testing, and van gene determination by polymerase chain reaction were performed in a central laboratory. Overall, 18 vanA and 5 vanB isolates of VRE were found. The prevalence of vanA VRE was highest in the UK (2.7%), while the prevalence of vanB VRE was highest in Slovenia (2%). Most vanA and vanB VRE were identified as Enterococcus faecium. Most VRE isolates originated from the patient's urogenital tract, skin, or digestive tract. VRE were equally distributed among clinical departments, with no clear preponderance in any single patient group. A total of 71 isolates containing the vanC gene were identified. The prevalence of vanC VRE was highest in Latvia and Turkey, where rates were 14.3 and 11.7%, respectively. Two-thirds of these isolates were identified as Enterococcus gallinarum and one-third as Enterococcus casseliflavus; the majority of these isolates were cultured from feces. Almost all isolates were obtained from hospitalized patients, mostly children. The highest prevalence of high-level gentamicin-resistant enterococci was seen in Turkey and Greece. In general, the distribution of this resistance type seemed unrelated to the occurrence of VRE. The prevalence of vanA/ vanB VRE in Europe is still low; the majority of the VRE isolates exhibit the vanC genotype and colonize the gastrointestinal tract of hospitalized children.

Adolescent↗

Prophylaxis and treatment of fungal infections associated with haematological malignancies.

Patients with haematological malignancies form one of the most susceptible host groups for microbial infection, especially during neutropenia. The incidence of invasive fungal infections has increased in recent years, highlighting the need for better diagnosis and more effective antifungal therapies. Amphotericin B is the drug of choice for many fungal infections, although toxicity and the need for intravenous infusion restrict its use. When possible, oral administration of antifungal agents is preferable but intravenous administration is often needed and current oral agents have their limitations: fluconazole because of a narrow spectrum of activity; itraconazole capsules because of erratic absorption. In this review, prophylactic and treatment options for systemic fungal infections are discussed. The specific needs of patients with different types of leukaemia and the benefits of new amphotericin B and itraconazole formulations are examined.

Amphotericin B↗

Microbiological diagnosis of invasive fungal infections in transplant recipients.

Invasive fungal infections remain an important cause of morbidity and mortality in transplant recipients. Since conventional diagnostic tools such as culture lack sensitivity and specificity, alternative diagnostic assays have been developed. Among the most promising techniques are the detection of fungal DNA and serology. Fungal DNA can be detected with high sensitivity and specificity when performed with specimens from sterile sites such as blood. Polymerase chain reaction (PCR) assays can be used to detect a broad range of fungal pathogens and combined with species identification. Multicenter diagnostic studies are needed to establish the diagnostic value of PCR but lack of standardization hampers such studies. The serodiagnosis of invasive fungal infections has become an important tool in the management of invasive fungal infections. Especially the detection of circulating galactomannan has been shown to be a sensitive marker for invasive aspergillosis. Both serology and PCR can be used to monitor the response to antifungal therapy. The optimal use of non-culture-based methods is in prospective screening of patients at high risk. Since the incidence of disease greatly influences the positive predictive value, screening should take place only in those patients at very high risk for invasive fungal disease.

Aspergillosis↗

Atypical presentation of Madurella mycetomatis mycetoma in a renal transplant patient.

A renal transplant patient presented with a swelling on his foot. Fungal hyphae were found in the abscess, and culture demonstrated Madurella mycetomatis, an agent of mycetoma. There were no black grains in the pus and no overlying sinuses. This was an atypical presentation of maduromycosis in a renal transplant patient.

Drug Therapy, Combination↗

Protection against Plasmodium falciparum malaria in chimpanzees by immunization with the conserved pre-erythrocytic liver-stage antigen 3.

In humans, sterile immunity against malaria can be consistently induced through exposure to the bites of thousands of irradiated infected mosquitoes. The same level of protection has yet to be achieved using subunit vaccines. Recent studies have indicated an essential function for intrahepatic parasites, the stage after the mosquito bite, and thus for antigens expressed during this stage. We report here the identification of liver-stage antigen 3, which is expressed both in the mosquito and liver-stage parasites. This Plasmodium falciparum 200-kilodalton protein is highly conserved, and showed promising antigenic and immunogenic properties. In chimpanzees (Pan troglodytes), the primates most closely related to humans and that share a similar susceptibility to P. falciparum liver-stage infection, immunization with LSA-3 induced protection against successive heterologous challenges with large numbers of P. falciparum sporozoites.

Animals↗

Hyaluronic acid-based agents do not affect anastomotic strength in the rat colon, in either the presence or absence of bacterial peritonitis.

BACKGROUND: Hyaluronic acid (HA) agents reduce postsurgical adhesion formation. The effect of their perioperative administration on early anastomotic healing is unknown. This study investigated the influence of two HA-containing agents on the development of strength in colonic anastomosis during the first postoperative week, both in normal rats and in rats with bacterial peritonitis. METHODS: In 90 male Wistar rats a 1-cm segment was resected from the descending colon and an end-to-end anastomosis was constructed. In 108 rats a bacterial peritonitis was induced using caecal ligation and puncture (CLP). Some 24 h after CLP the abdomen was reopened, the caecum was taken out and, after resection of a 1-cm segment, an anastomosis was made. Animals in both groups were randomized to receive either an HA-carboxymethylcellulose (CMC) bioresorbable membrane, 0.4 per cent HA solution or no treatment. One-third of each group was killed at day 1, 3 and 7 after operation. Cultures were taken from the abdominal cavity for microbiological analysis in half of the animals. Subsequently, both bursting pressure and breaking strength were determined as parameters for anastomotic strength. RESULTS: No differences in anastomotic bursting pressure or breaking strength were found between the experimental groups and their controls. In addition, there was no significant difference in the number of bacteria cultured from the abdominal cavity between rats treated with HA and controls. CONCLUSION: Neither HA-CMC bioresorbable membrane nor 0.4 per cent HA solution interferes with the development of early anastomotic strength in the colon, and can therefore be safely used to prevent intra-abdominal adhesion formation after performing bowel anastomosis.

Adjuvants, Immunologic↗

In vitro susceptibilities of 11 clinical isolates of Exophiala species to six antifungal drugs.

The antifungal activities of miconazole, terbinafine, itraconazole, UR 9825, voriconazole and amphotericin B against 11 clinical isolates of Exophiala spp. were tested by the broth microdilution method. All drugs were very active against Exophiala spp.. The 90% minimal inhibitory concentration (MIC90) ranged from 0.125 to 1 microgram ml-1. Terbinafine was the most active drug against Exophiala spinifera, Exophiala dermatitidis and Exophiala castellanii and seems to be a promising agent in the treatment of infections caused by these fungi.

Antifungal Agents↗

In vitro interaction of terbinafine with itraconazole against clinical isolates of Scedosporium prolificans.

In order to develop new approaches for the chemotherapy of invasive infections caused by Scedosporium prolificans, the in vitro interaction between itraconazole and terbinafine against 20 clinical isolates was studied using a checkerboard microdilution method. Itraconazole and terbinafine alone were inactive against most isolates, but the combination was synergistic against 95 and 85% of isolates after 48 and 72 h of incubation, respectively. Antagonism was not observed. The MICs obtained with the terbinafine-itraconazole combination were within levels that can be achieved in plasma.

Ascomycota↗

Procalcitonin does not discriminate infection from inflammation after allogeneic bone marrow transplantation.

Procalcitonin (PCT) is an early marker of bacterial infection but little is known about its value in neutropenic allogeneic bone marrow transplant (BMT) recipients. We collected plasma from 12 recipients of T-cell-depleted HLA-matched related BMT recipients who had been treated preemptively with meropenem from the day after BMT for at least 15 days. PCT and C-reactive protein (CRP) concentrations were determined on BMT days 1, 5, 8, 12, and 15, and their relationship to inflammatory events (IE), including mucositis, microbiologically and clinically defined infections, acute graft-versus-host disease (GVDH), and unexplained fever, was then determined. The PCT concentrations were all low and never exceeded 4 microg/liter, unlike CRP concentrations, which spanned the full range up to 350 mg/liter. All patients had mucositis, and there was no significant difference between PCT concentrations associated with mucositis alone and those associated with an additional IE on BMT days 1 to 12. However, on BMT day 15, the mean concentrations of PCT were 0.37 +/- 0.05 microg/liter for the 10 patients that had an additional IE, compared with 0.11 +/- 0.03 microg/liter for the 2 patients with mucositis only (P = 0.012), and GVHD rather than infection was involved in six cases. PCT was also not a sensitive marker of gram-positive bacteremia or pulmonary aspergillosis. Thus, PCT is of little value in discriminating infections from other inflammatory complications that occur following allogeneic BMT.

Adult↗

Comparison of NCCLS and 3-(4,5-dimethyl-2-Thiazyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) methods of in vitro susceptibility testing of filamentous fungi and development of a new simplified method.

The susceptibility of 30 clinical isolates belonging to six different species of filamentous fungi (Aspergillus fumigatus, Aspergillus flavus, Scedosporium prolificans, Scedosporium apiospermum, Fusarium solani, and Fusarium oxysporum) was tested against six antifungal drugs (miconazole, voriconazole, itraconazole, UR9825, terbinafine, and amphotericin B) with the microdilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) (M38-P). The MICs were compared with the MICs obtained by a colorimetric method measuring the reduction of the dye 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan by viable fungi. The levels of agreement between the two methods were 96 and 92% for MIC-0 (clear wells) and MIC-1 (75% growth reduction), respectively. The levels of agreement were always higher for Aspergillus spp. (97% +/- 2.5%), followed by Scedosporium spp. (87% +/- 10.3%) and Fusarium spp. (78% +/- 7.8%). The NCCLS method was more reproducible than the MTT method: 98 versus 95% for MIC-0 and 97 versus 90% for MIC-1. However, the percentage of hyphal growth as determined visually by the NCCLS method showed several discrepancies when they were compared with the percentages of MTT reduction. A new simplified assay that incorporates the dye MTT with the initial inoculum and in which the fungi are incubated with the dye for 48 h or more was developed, showing comparable levels of agreement and reproducibility with the other two methods. Furthermore, the new assay was easier to perform and more sensitive than the MTT method.

Antifungal Agents↗

Invasive aspergillosis.

Acute invasive aspergillosis (IA) is a devastating disease. Early diagnosis allowing an early treatment may improve the prognosis. However, this goal remains difficult to achieve. When diagnosis is confirmed it is often already too late. Galactomannan antigen detection and DNA detection are under clinical evaluation to improve early diagnosis and management of treatment. Despite antifungal treatment mortality rate is still high. Clinical resistance is more often due to the intensity of immunodepression than to high minimum inhibitory concentrations to antifungal agents; however, resistance to itraconazole may occur in rare instances. Beside acute IA, a chronic form of this infection may be seen as chronic necrotizing pulmonary aspergillosis or chronic invasive sinusitis. Other sites of infection have been described. The patients are immunocompetent or present minor alteration of their immunity or of anatomic structure of the infected site. Among patients with solid organ transplantation, lung and liver transplant patients are at the highest risk of developing IA. A high degree of awareness and efforts for an early diagnosis may participate to improve the poor prognosis.

Antifungal Agents↗

[Scedosporiosis of the brain with fatal outcome after traumatizatio of the foot. case report].

A 33 year old German man suffered from a wound of his foot after an accident. He developed an osteomyelitis. From wound probes Scedosporium apiospermum could be isolated for several times. Some weeks later a cerebral lesion could be diagnosed. The lesion was extirpated and again S. apiospermum could be cultured from the cerebral probes. A few weeks later the patient died and some new cerebral lesions could be diagnosed by CT-scan.

Adult↗

Increased susceptibility of TNF-alpha lymphotoxin-alpha double knockout mice to systemic candidiasis through impaired recruitment of neutrophils and phagocytosis of Candida albicans.

TNF-alpha and lymphotoxin-alpha (LT) are members of the TNF family, and these cytokines play crucial roles in the defense against infection with Candida albicans. The aim of the present study was to investigate the role of endogenous TNF and LT during disseminated candidiasis in TNF-/-LT-/- knockout mice. The TNF- and LT-deficient animals had a significantly increased mortality following C. albicans infection compared with control mice, and this was due to a 10- to 1000-fold increased outgrowth of the yeast in their organs. No differences between TNF-/-LT-/- mice and TNF+/+LT+/+ were observed when mice were rendered neutropenic, suggesting that activation of neutrophils mediates the beneficial effects of endogenous TNF and LT. Histopathology of the organs, combined with neutrophil recruitment experiments, showed a dramatic delay in the neutrophil recruitment at the sites of Candida infection in the TNF-/-LT-/- mice. Moreover, the neutrophils of deficient animals were less potent to phagocytize Candida blastospores than control neutrophils. In contrast, the killing of Candida and the oxygen radical production did not differ between neutrophils of TNF-/-LT-/- and TNF+/+LT+/+ mice. Peak circulating IL-6 was significantly higher in TNF-/-LT-/- mice during infection. Peritoneal macrophages of TNF-/-LT-/- mice did not produce TNF, and synthesized significantly lower amounts of IL-1alpha, IL-1beta, IL-6, and macrophage-inflammatory protein-1alpha than macrophages of TNF+/+LT+/+ animals did. In conclusion, endogenous TNF and/or LT contribute to host resistance to disseminated candidiasis, and their absence in TNF-/-LT-/- mice renders the animals susceptible through impaired recruitment of neutrophils and impaired phagocytosis of C. albicans.

Animals↗

Perianal ulcer.

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Crohn Disease↗