Elisabeth Presterl

The Candida albicans Cdr2p ATP-binding cassette (ABC) transporter confers resistance to caspofungin

Multidrug resistance may pose a serious problem to antifungal therapy. The Candida albicans Cdr2p is one of two ATP‐binding cassette (ABC) transporters mediating antifungal resistance in vivo through increased drug efflux. Echinocandins such as caspofungin represent the newest class of antifungals that target cell wall synthesis. We show here by agar plate resistance assays that cross‐resistant clinical isolates of C. albicans display high minimal inhibitory concentrations (MICs) to caspofungin when compared with a sensitive ATCC reference strain. Northern analysis and immunoblotting indicate that these isolates also show high levels of CDR1 and CDR2 expression. To determine a possible contribution of Cdr1p or Cdr2p to caspofungin resistance, we have functionally expressed Cdr1p and Cdr2p in appropriate recipient strains of the yeast Saccharomyces cerevisiae. Yeast cells expressing Cdr1p or Cdr2p exhibit cross‐resistance to established antifungal drugs such as azoles and terbinafine. However, Cdr2p and, to a much lesser extent, Cdr1p confer caspofungin hyper‐resistance when expressed in yeast. Likewise, Cdr2p confers caspofungin resistance when constitutively overexpressed in a drug‐sensitive C. albicans strain. We therefore propose that Cdr2p may contribute to clinical candin resistance. Finally, our data suggest that cross‐resistance phenotypes of clinical isolates are the consequence of distinct mechanisms that may operate simultaneously.

Diagnosis and therapy of Candida infections: joint recommendations of the German Speaking Mycological Society and the Paul‐Ehrlich‐Society for Chemotherapy

Invasive Candida infections are important causes of morbidity and mortality in immunocompromised and hospitalised patients. This article provides the joint recommendations of the German‐speaking Mycological Society (Deutschsprachige Mykologische Gesellschaft, DMyKG) and the Paul‐Ehrlich‐Society for Chemotherapy (PEG) for diagnosis and treatment of invasive and superficial Candida infections. The recommendations are based on published results of clinical trials, case‐series and expert opinion using the evidence criteria set forth by the Infectious Diseases Society of America (IDSA). Key recommendations are summarised here: The cornerstone of diagnosis remains the detection of the organism by culture with identification of the isolate at the species level; in vitro susceptibility testing is mandatory for invasive isolates. Options for initial therapy of candidaemia and other invasive Candida infections in non‐granulocytopenic patients include fluconazole or one of the three approved echinocandin compounds; liposomal amphotericin B and voriconazole are secondary alternatives because of their less favourable pharmacological properties. In granulocytopenic patients, an echinocandin or liposomal amphotericin B is recommended as initial therapy based on the fungicidal mode of action. Indwelling central venous catheters serve as a main source of infection independent of the pathogenesis of candidaemia in the individual patients and should be removed whenever feasible. Pre‐existing immunosuppressive treatment, particularly by glucocorticosteroids, ought to be discontinued, if feasible, or reduced. The duration of treatment for uncomplicated candidaemia is 14u2003days following the first negative blood culture and resolution of all associated symptoms and findings. Ophthalmoscopy is recommended prior to the discontinuation of antifungal chemotherapy to rule out endophthalmitis or chorioretinitis. Beyond these key recommendations, this article provides detailed recommendations for specific disease entities, for antifungal treatment in paediatric patients as well as a comprehensive discussion of epidemiology, clinical presentation and emerging diagnostic options of invasive and superficial Candida infections.

Helicobacter pylori Urease Significantly Reduces Opsonization by Human Complement

The role of Helicobacter pylori urease in opsonization by human complement was investigated. H. pylori wild type strain N6 and isogenic mutants lacking either the large urease subunit (UreB) or an accessory urease protein (UreG) were incubated with different sera. C3b bound to the bacteria was measured by specific staining and flow cytometry. As compared with opsonization of N6 and the UreG-lacking mutant, opsonization of the UreB-lacking mutant was significantly increased after incubation with sera from both H. pylori uninfected (P<.001) or infected (P<.05) persons. However, when sera from uninfected persons were used, effective opsonization of this mutant proved to be dependent mainly on the classical pathway of complement activation. Irrespective of the serum used, opsonization values were very low after selective inactivation of the classical or the alternative pathway. Reduced opsonization of the urease-expressing strains could, to some extent, result from degradation of bound C3b.

Influence of pentoxifylline on cytokine levels and inflammatory parameters in septic shock.

ObjectiveTo evaluate the influence of pentoxifylline (PTX), a phosphodiesterase inhibitor, on cytokines and inflammatory proteins in patients suffering from septic shock.DesignProspective study comparing a therapy group to a matched control group.SettingMedical intensive care unit at a university hospital.PatientsTwenty four patients fulfilling the criteria of septic shock were included in this study. Twelve patients received PTX (therapy group) and 12 patients matched for diagnosis, age and gender served as the control group.InterventionsPentoxifylline at 1 mg/kg per hour over 24 h in the therapy group.Measurements ad resultsCytokine levels [tumor necrosis factor-α (TNF)], soluble TNF receptor [TNF-R], and interleukin-6 [IL-6] and inflammatory proteins [C-reactive protein, α-1-antitrypsin (AAT), fibronectin, and haptoglobin], as well as hemodynamic parameters and the APACHE III score were evaluated before initiation of therapy and 24 h later. After 24 h, TNF levels were significantly lower in the therapy group (p=0.013), while IL-6 levels were significantly higher in the therapy group (p=0.030). Within the 24 h TNF declined significantly in the therapy group (p=0.006), while IL-6 showed a significant increase (p=0.043). AAT and the APACHE III score tended to differ significantly after 24 h between the groups [AAT levels higher in the therapy group (p=0.05), APACHE III score lower (p=0.05)]. In the therapy group, the systemic vascular resistance index was significantly higher after 24 h (p=0.0026) whereas the cardiac index declined (p=0.035).ConclusionsPTX does influence TNF levels in septic shock patients. Nevertheless, inhibiting a single mediator in severe septic shock cannot stop the inflammatory overreaction.

Management of serious staphylococcal infections in the outpatient setting

SummaryPatients with serious staphylococcal infections, e.g. endocarditis and osteomyelitis, need prompt and prolonged parenteral antibiotic treatment to ensure eradication of the causative pathogen. The major cost in the treatment of these infections is the long period of hospitalisation required for the administration of intravenous antibiotics. To shorten the hospitalisation period, outpatient treatment can be given to some patients.In this study, patients with acute exacerbations of chronic osteomyelitis (n=44) or endocarditis (n=10) were treated with intravenous teicoplanin. The pathogens were Staphylococcus aureus (n=41,13 of which were methicillin resistant) and coagulase-negative staphylococci (n=13, one of which was methicillin resistant). After a mean loading dose of 15 mg/kg for 3 to 10 days, patients received teicoplanin 3 times a week at a dose (mean 15 mg/kg) individualised to achieve serum trough concentrations of approximately 10 mg/L for osteomyelitis and 20 mg/L for endocarditis. Treatment duration ranged from 28 to 150 (mean 62) days for patients with osteomyelitis and from 28 to 88 (mean 49) days for patients with endocarditis. 37 (84%) patients with osteomyelitis and 8 (80%) patients with endocarditis were treated successfully. Adverse events were ob-served in 9 patients and included rash (n=3), thrombocytopenia (n=3), and drug fever, pseudomembranous colitis, nausea, leucopenia and transient hearing impairment (one patient each).In conclusion, this study demonstrates that teicoplanin can be administered successfully in an outpatient setting according to a 3-times weekly schedule for the treatment of patients with staphylococcal osteomyelitis and endocarditis.

Enteroaggregative and Enterotoxigenic Escherichia coli among Isolates from Patients with Diarrhea in Austria

Abstractu2002In a 3-month prospective study among 203 Austrian outpatients with diarrhea, the role of pathogenic Escherichia coli and the use of the polymerase chain reaction in screening Escherichia coli isolates from clinical stool specimens were evaluated. Enteroaggregative Escherichia coli and enterotoxigenic Escherichia coli combined were identified as the second most frequent cause of diarrhea. Of a total of 85 bacterial pathogens isolated from 80 patients, 15 were pathogenic Escherichia coli, 13 enteroaggregative Escherichia coli and two enterotoxigenic Escherichia coli. Enteropathogenic, enteroinvasive, and enterohemorrhagic Escherichia coli isolates were not detected.

Antifungal Susceptibility Testing of Fluconazole by Flow Cytometry Correlates with Clinical Outcome

ABSTRACT Susceptibility testing of fungi by flow cytometry (also called fluorescence-activated cell sorting [FACS]) using vital staining with FUN-1 showed a good correlation with the standard M27-A procedure for assessing MICs. In this study we determined MICs for blood culture isolates from patients with candidemia by NCCLS M27-A and FACS methods and correlated the clinical outcome of these patients with in vitro antifungal resistance test results. A total of 24 patients with candidemia for whom one or more blood cultures were positive for aCandida sp. were included. Susceptibility testing was performed by NCCLS M27-A and FACS methods. The correlation of MICs (NCCLS M27-A and FACS) and clinical outcome was calculated. In 83% of the cases, the MICs of fluconazole determined by FACS were within 1 dilution of the MICs determined by the NCCLS M27-A method. For proposed susceptibility breakpoints, there was 100% agreement between the M27-A and FACS methods. In the FACS assay, a fluconazole MIC of <1 μg/ml was associated with cure (P < 0.001) whereas an MIC of ≥1 μg/ml was associated with death (P < 0.001). The M27-A-derived fluconazole MICs did not correlate with outcome (P = 1 and P = 0.133).

Successful conservative treatment of severe renal candidosis with fungus balls

Abstractu2002Partial fungal obstruction of the renal collecting system is an unusual finding among infants that poses specific management problems. We report a patient with sepsis and fungal infection of the kidneys post surgery who presented with bilateral fungus balls and was successfully managed by conservative measures. Sonography is the imaging technique of choice in the diagnosis and follow-up of such patients. The need for prompt diagnosis in high-risk patients and the role of sonography are discussed.

Ciprofloxacin- and methicillin-resistant Staphylococcus aureus susceptible to moxifloxacin, levofloxacin, teicoplanin, vancomycin and linezolid

Abstractu2002In order to determine the comparative efficacy of vancomycin, teicoplanin, levofloxacin, moxifloxacin, and linezolid against methicillin- and ciprofloxacin-resistant Staphylococcus aureus, each agent was tested against 65 genetically different strains using the microbroth dilution method. All of the isolates were typed using the enterobacterial repetitive intergenic consensus polymerase chain reaction to exclude multiple isolates of epidemic clones. Susceptibility testing revealed that all of the isolates were susceptible to vancomycin and teicoplanin. Linezolid exhibited minimum inhibitory concentration (MIC) levels ranging from 1 to 4u2009mg/l (MIC90, 4u2009mg/l). The MICs of moxifloxacin and levofloxacin ranged from 0.01 to 8u2009mg/l (MIC90, 8u2009mg/l) and 0.25 to 32u2009mg/l (MIC90, 16u2009mg/l), respectively. Thus, linezolid is active against methicillin- and ciprofloxacin-resistant Staphylococcus aureus, whereas moxifloxacin may need to be administered at a dose higher than recommended in order to successfully treat serious infections.

Molecular typing of Acinetobacter baumannii from ten different intensive care units of a university hospital

Thirty-one isolates ofAcinetobacter baumannii were collected from ten intensive care units of an Austrian university hospital. All isolates were typed by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Two strains colonizing 13 infants in the neonatal intensive care unit were identified by ERIC-PCR. All otherAcinetobacter baumannii isolates had highly divergent ERIC-PCR patterns, despite having the same antibiogram. Thus, a hospital-wide clonal distribution, as suggested by identical antibiogram patterns, was excluded by ERIC-PCR.