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The reported prevalence of vancomycin-resistant Enterococcus faecium (VRE) in Switzerland for the years 2008–2010 has been low at <5%. At the University Hospital Zurich, 17 cases of VRE were detected between 28 December 2009 and 15 February 2010. Nine cases were diagnosed clinically; eight cases were detected by rectal screening. The centre of the outbreak was the cardiac surgery department. Four patients suffered from VRE-infections; four patients died. In order to investigate and contain the outbreak, the following measures were taken: prevalence surveys using weekly rectal screening, environmental screening; selective enrichment culturing; pulsed field gel electrophoresis (PFGE) for clonal typing and polymerase chain reaction-analysis (PCR) for resistance determinants and virulence factors detection. Contact isolation in single rooms and enhanced surface-disinfection methods were implemented. Ward nurses were assigned as link nurses. Regular teaching was carried out aiming to improve hand disinfection among healthcare workers. PFGE revealed two main pulsotypes each including seven patients. Five minor pulsotypes originated from three additional patients and one sample collected from a keyboard. Two of three patients with minor pulsotypes had been treated abroad. PCR-analysis identified vanB resistance-genotypes with exception of one vanA resistance-genotype. The outbreak was associated with environmental contamination and insufficient compliance with hand-hygiene. Enhanced awareness and infection control measures resulted in termination of the VRE outbreak within eight weeks. The complexity of the outbreak with several clones in parallel suggests a higher baseline prevalence of VRE in Switzerland than previous surveillance data indicate.

PURPOSE: The aim of this quality control study was to assess the time to initial diagnostic procedures and the time to the first dose of antibiotics in patients with pneumococcal bacteremia, and to investigate whether the timeliness of these interventions influenced outcome. METHODS: We retrospectively studied patient characteristics, chronological sequence of diagnostic and therapeutic steps, and the course of disease of all patients with pneumococcal bacteremia at a Swiss university hospital between 2003 and 2009, and we analyzed associations between these factors and the length of hospital stay (LOS) and mortality. RESULTS: A total of 102 episodes of pneumococcal bacteremia in 98 patients were analyzed, of whom 15.7% died during hospitalization. The median time (interquartile range [IQR]) to the first antibiotic dose was 4.0 (2.0-5.9) h, and the median times (IQR]) to blood cultures, chest radiograph, lumbar puncture, and brain computed tomography (CT) scan or magnetic resonance imaging (MRI) were 1.4 (0.5-3.3), 2.5 (1.2-4.2), 4.2 (2.7-7.2), and 2.3 (0.6-6.2) h, respectively. The time to diagnostic procedures and therapy were not associated with LOS or death. Risk factors for death in the univariable analysis were: Charlson comorbidity index [odds ratio [OR] (95% confidence interval) per unit increase, 1.3 (1.1-1.6)], neutropenia [OR 10.1 (2.0-51.0)], human immunodeficiency virus (HIV) infection [OR 3.9 (1.1-13.8)], chronic respiratory disease [OR 4.4 (1.2-16.0)], chronic liver disease [OR 3.2 (1.0-9.7)], smoking [OR 3.8 (1.1-13.5)], injection drug use [OR 9.7 (1.5-63.7)], and antibiotic therapy within 6 months before admission [OR 4.0 (1.3-12.5)]. The multivariable analysis revealed age >60 years (P = 0.048) and alcoholism (P = 0.009) as risks for prolonged LOS. CONCLUSIONS: The outcome of pneumococcal bacteremia may be more influenced by patient characteristics than by minor differences in the timeliness of initial diagnostic and therapeutic measures within the

BACKGROUND: There are considerable geographical differences in the occurrence of extended-spectrum beta-lactamase(ESBL)-producing bacteria, both in the community and in the hospital setting. Our aim was to assess risk factors for blood stream, urinary tract, and vascular catheter-associated infections with ESBL-producing Escherichia coli and Klebsiella pneumoniae at a tertiary care hospital in a low-prevalence country. METHODS: We performed a case-control study comparing 58 patients with infections due to ESBL-producing E. coli orK. pneumoniae vs 116 controls with infections due to non-ESBL producing organisms at the University Hospital Zurich, Switzerland, between 1 July 2005 and 30 June 2007. RESULTS: Cases included 15 outpatients and 43 inpatients. Multivariable analyses found three risk factors for ESBL-producing isolates: begin of symptoms or recent antibiotic pre-treatment in a foreign country (odds ratio [OR] 27.01,95% confidence interval [CI] 2.38-1,733.28], p = 0.042),antibiotic therapy within the year preceding the isolation of the ESBL-producing strain (OR 2.88, 95% CI 1.13-8.49,p = 0.025), and mechanical ventilation (OR 10.56, 95% CI 1.06-579.10, p = 0.042). CONCLUSIONS: The major risk factors for infections due to ESBL-producing bacteria were travel in high-prevalence countries, prior antibiotic use, and mechanical ventilation during a stay in the intensive care unit. Community-acquired infections were documented in 17% of the patients.An early identification of risk factors is crucial to providing the patients an optimal empiric antibiotic therapy and to keep the use of carbapenems to a minimum.

QUESTIONS UNDER STUDY: Monitoring of antimicrobial resistance is a key component of antibiotic stewardship programs. In 2007, a significantly higher resistance rate of Escherichia coli to ciprofloxacin was found at the Department of Urology, University Hospital Zurich, Switzerland, when compared to other hospital units. Thus, we aimed to determine the risk factors for this increased fluoroquinolone resistance in outpatients and inpatients with urinary tract infection (UTI) or colonisation with E. coli. METHODS: We performed a cross sectional study including 275 patients of the Department of Urology in whom E. coli was isolated from urine or blood cultures between 01.01.2006 and 31.08.2007. Clinical data were collected from patients' records using a structured questionnaire. Multivariable analysis was performed for the detection of risk factors. RESULTS: Ciprofloxacin-resistant E. coli was detected in 22% of patients. Risk factors for ciprofloxacin-resistant E. coli included prior use of fluoroquinolones (odds ratio [OR] (95% confidence intervals): 2.24 (1.08-4.62), p = 0.030), prior urinary tract catheterisation (OR: 2.41 (1.02-5.67), p = 0.044) and recurrent UTIs (OR: 2.26 (1.07-4.78), p = 0.032). 60.8% of all prescriptions in urinary tract infections were for fluoroquinolones, and this antibiotic class was the empiric antibiotic regimen of choice in 72.5% of all acute, uncomplicated, urinary tract infections. CONCLUSIONS: The increasing prevalence of ciprofloxacin-resistant E. coli makes empiric therapy in UTIs with this agent questionable, especially in patients with one or several of the above mentioned risk factors. Due to the increasing resistance rate, continuous surveillance and susceptibility testing in individual patients, particularly with complicated UTIs, is indispensable for adequate therapy Methods: We performed a cross sectional study including 275 patients of the Department of Urology in whom E. coli was isolated from urine or blood cultures between

Audits of individual patient care provide important data to identify local problems in antimicrobial prescription practice. In our study, antimicrobial prescriptions without indication, and divergence from institutional guidelines were frequent errors. Based on these results, we will tailor education, amend institutional guidelines and further develop the infectious diseases consultation service.

Low-grade infection was systematically searched for in all revision shoulder surgeries by harvesting tissue samples. Ten consecutive patients were identified with a non-purulent low-grade infection of the shoulder. All of these patients suffered from pain and eight were stiff. Preoperative aspiration in eight patients yielded bacterial growth in only one case. Serum C-reactive protein levels were normal in seven out of 10 cases. Propionibacterium acnes was identified in seven, coagulase-negative Staphylococcus in two and Staphylococcus saccharolyticus in one case. The delay between harvesting the tissue samples and detection of bacterial growth averaged eight days (range, 2-17). After debridement and antibiotic treatment for a mean of 4.5 months, tissue samples were repeatedly harvested in nine patients due to persistent pain. The infection was microbiologically eradicated in six out of nine cases that had a repeated biopsy. However, nine out of 10 patients continued to suffer from moderate to severe pain. Low-grade infection of the shoulder can be a cause of persistent pain and stiffness. The results of antibiotic treatment are disappointing. Further studies are necessary to analyse this difficult pathology.

BACKGROUND: Antimicrobial resistance may compromise the efficacy of antibiotic prophylaxis before surgery. The aim of this study was to measure susceptibility and clonal distribution of coagulase-negative staphylococci (CoNS) colonizing the skin around the surgery access site before and after the procedure. METHODS: From March to September 2004, a series of 140 patients undergoing elective major abdominal surgery were screened for CoNS colonization at admission and 5 days after surgery. All isolates were tested for antibiotic susceptibility and genotyped by pulsed-field gel electrophoresis (PFGE). RESULTS: Colonization rates with CoNS at admission and after surgery were 85% and 55%, respectively. The methicillin-resistant CoNS rate increased from 20% at admission to 47% after surgery (P = 0.001). The PFGE pattern after surgery revealed more patients colonized with identical clones: 8/140 patients (8/119 strains) and 26/140 patients (26/77 strains), respectively (P < 0.001). CONCLUSIONS: Our results suggest rapid recolonization of disinfected skin by resistant nosocomial CoNS. Larger studies, preferably among orthopedic or cardiovascular patients, are required to clarify whether standard antibiotic prophylaxis with first- or second-generation cephalosporins for CoNS infections may be compromised if the patient requires an additional intervention 5 days or more after the initial surgery.

Background Empirical antibiotic therapy is based on patients' characteristics and antimicrobial susceptibility data. Hospital-wide cumulative antibiograms may not sufficiently support informed decision-making for optimal treatment of hospitalized patients. Methods We studied different approaches to analysing antimicrobial susceptibility rates (SRs) of all diagnostic bacterial isolates collected from patients hospitalized between July 2005 and June 2007 at the University Hospital in Zurich, Switzerland. We compared stratification for unit-specific, specimen type-specific (blood, urinary, respiratory versus all specimens) and isolate sequence-specific (first, follow-up versus all isolates) data with hospital-wide cumulative antibiograms, and studied changes of mean SR during the course of hospitalization. Results A total of 16 281 isolates (7965 first, 1201 follow-up and 7115 repeat isolates) were tested. We found relevant differences in SRs across different hospital departments. Mean SRs of Escherichia coli to ciprofloxacin ranged between 64.5% and 95.1% in various departments, and mean SRs of Pseudomonas aeruginosa to imipenem and meropenem ranged from 54.2% to 100% and 80.4% to 100%, respectively. Compared with hospital cumulative antibiograms, lower SRs were observed in intensive care unit specimens, follow-up isolates and isolates causing nosocomial infections (except for Staphylococcus aureus). Decreasing SRs were observed in first isolates of coagulase-negative staphylococci with increasing interval between hospital admission and specimen collection. Isolates from different anatomical sites showed variations in SRs. Conclusions We recommend the reporting of unit-specific rather than hospital-wide cumulative antibiograms. Decreasing antimicrobial susceptibility during hospitalization and variations in SRs in isolates from different anatomical sites should be taken into account when selecting empirical antibiotic treatment.

BACKGROUND: To compare the quantitative antibiotic use between hospitals or hospital units and to explore differences, adjustment for severity of illness of hospitalized patients is essential. The case mix index (CMI) is an economic surrogate marker (i.e. the total cost weights of all inpatients per a defined time period divided by the number of admissions) to describe the average patients' morbidity of individual hospitals. We aimed to investigate the correlation between CMI and hospital antibiotic use. METHODS: We used weighted linear regression analysis to evaluate the correlation between in-hospital antibiotic use in 2006 and CMI of 18 departments of the tertiary care University Hospital Zurich and of 10 primary and 2 secondary acute care hospitals in the Canton of Zurich in Switzerland. RESULTS: Antibiotic use varied substantially between different departments of the university hospital [defined daily doses (DDD)/100 bed-days, 68.04; range, 20.97-323.37] and between primary and secondary care hospitals (range of DDD/100 bed-days, 15.45-57.05). Antibiotic use of university hospital departments and the different hospitals, respectively, correlated with CMI when calculated in DDD/100 bed-days [coefficient of determination (R(2)), 0.57 (P = 0.0002) and 0.46 (P = 0.0065)], as well as when calculated in DDD/100 admissions [R(2), 0.48 (P = 0.0008) and 0.85 (P < 0.0001), respectively]. CONCLUSIONS: Antibiotic use correlated with CMI across various specialties of a university hospital and across different acute care hospitals. For benchmarking antibiotic use within and across hospitals, adjustment for CMI may be a useful tool in order to take into account the differences in hospital category and patients' morbidities.

We investigate the behavior of N atoms resonantly coupled to a single electromagnetic field mode sustained by a high quality cavity, containing a mesoscopic coherent field. We show with a simple effective Hamiltonian model that the strong coupling between the cavity and the atoms produces an atom-field entangled state, involving N+1 nearly coherent components slowly rotating at different paces in the phase plane. The periodic overlap of these components results in a complex collapse and revival pattern for the Rabi oscillation. We study the influence of decoherence due to the finite cavity quality factor. We propose a simple analytical model, based on the Monte Carlo approach to relaxation. We compare its predictions with exact calculations and show that these interesting effects could realistically be observed on a two or three atoms sample in a 15 photon field with circular Rydberg atoms and superconducting cavities., Kavli Institute of Nanoscience, Applied Sciences

Mittels Gelenkprothese kann bei Patienten mit arthrotisch oder arthritisch destruierten Gelenken (Hüfte, Knie, Schulter und Ellenbogen) Schmerzfreiheit erreicht und gleichzeitig die Mobilität gesteigert werden. Die Gelenkprotheseninfektion gilt als schwerwiegende, implantatassoziierte Komplikation, welche mit erhöhter Morbidität und Gesundheitskosten einhergeht. Pathogenetisch handelt es sich bei der Gelenkprotheseninfektion um eine Fremdkörperinfektion mit Ausbildung eines Biofilms, was die Diagnose und Therapie erschwert. Low-grade-Infektionen einer Gelenkprothese manifestieren sich häufig in Form einer frühen Prothesenlockerung mit oder ohne persistierende Schmerzen. Klinisch ist somit ein Low-grade-Infekt kaum von einem aseptischen Prothesenversagen zu unterscheiden. Die definitive Diagnose einer Gelenkprotheseninfektion kann meistens erst durch die Kombination verschiedener prä- und intraoperativer Untersuchungen gestellt werden. Durch rheumatologische Grundkrankheiten kann das periprothetische Gewebe entzündlich verändert sein, sodass nur der kulturelle Nachweis des Mikroorganismus eine definitive Diagnose erlaubt. Der Therapieerfolg ist einerseits von einer adäquaten chirurgischen Intervention und andererseits von einer antibiotischen Langzeittherapie abhängig. Letztere sollte eine biofilmaktive Substanz enthalten. In diesem Artikel werden Pathogenese, Epidemiologie, Diagnostik und Therapie einer Gelenkprotheseninfektion diskutiert. Dabei wird der Schwerpunkt auf die diagnostische Abklärung gelegt, zumal diese bei rheumatologischer Grundkrankheit erschwert sein kann

Eine 74-jährige, polymorbide Patientin mit einer rheumatoiden Arthritis erlitt unter Therapie mit Methotrexat und Prednison eine Pneumocystis-jiroveci-Pneumonie (PcP). Eine Therapie mit Bactrim wurde eingeleitet. Trotz nicht mehr nachweisbaren Pneumozysten in einer Bronchiallavage verstarb die Patientin. Die genaue Todesursache blieb unklar. Wie dieses Beispiel zeigt, muss bei immunkompromittierten rheumatologischen Patienten an die Differenzialdiagnose einer PcP gedacht werden. Der typische Verlauf, Diagnose, Prophylaxe und Therapie der PcP bei dieser Patientengruppe werden diskutiert

Background and Aim: Contamination of endoscopy suites with bacteria during procedures is of concern particularly through droplets during handling of biopsy specimens. It has been advocated that suctioning while removing the biopsy forceps could help to reduce potentially hazardous bioaerosols. The aim of the present study was to evaluate the efficacy of air suctioning during removal of the biopsy forceps. Materials and Methods: Airborne bacteria were collected by an impactor air-sampler (MAS-100). Fifty liters of air were collected continuously for 30 seconds at a 30 cm distance from the colonoscope suction channel. Room air samples were taken in the endoscopy suite in the morning prior to the beginning of the endoscopy program, during colonoscopy with a sham biopsy in the descending colon with and without suctioning and at the end of the procedure day. Standard 90 mm Petri dishes containing a selective medium for gram-positive cocci (CNA blood agar) were used with the impaction sampler and colony forming units/m3 (cfu) were determined. Results: Measurements were performed at fifty consecutive colonoscopies. Prior to the beginning of the endoscopy program, the bioaerosol burden in the colonoscopy suite reached a mean of 4.2 cfu/m3. During colonoscopies performed without suctioning at biopsy the bioaerosol burden increased to 29.4 cfu/m3 whereas this burden increased only to 15.1 cfu/m3 when the suctioning was applied during removal of the biopsy forceps. The difference in bioaerosol burden between suctioning and no suctioning was highly significant (p < 0.0005). At the end of the procedure day the airborne bacteria count dropped to 15.6 cfu/m3. The analysis of the colonies on the CNA blood agar identified predominantly enterococci. Staphylococci spp. and other gram-positive bacteria were rarely isolated. Conclusion: The present study indicates that the bioaerosol burden during handling of biopsy specimens is not neglectable but can be reduced by the simple habit of

Staphylococcus aureus with resistance to glycopeptide antibiotics has been considered to be a rare cause of clinically relevant infections. A review of the current literature shows that this is indeed the case for infections caused by S. aureus with high-level resistance to vancomycin (VRSA), as only isolated cases have been reported. VRSA develops following the insertion of the vanA gene, which is transferred from enterococci with vancomycin resistance. On the other hand, infections caused by S. aureus with intermediate resistance to glycopeptides (VISA), or heterogeneously expressed intermediate level glycopeptide resistance (hVISA), are more common. These infections are associated with clinical failure of glycopeptide therapy. While the biochemical and phenotypic features including a thickened cell wall of hVISA and VISA are well known, the genetic basis of these phenotypes remains unknown. Certain genetic regulatory elements such as agr II are associated with reduced susceptibility of S. aureus to glycopeptides. Available data suggest that certain infections might be successfully treated using higher doses of vancomycin. However, as treatment failure is particularly common in infections with a high bacterial load, it may be necessary to resort to other antibiotics such as linezolid, often combined with surgical intervention, in order to successfully treat these infections. Open questions regarding diagnosis, pathogenesis, epidemiology, and treatment of glycopeptide resistance in S. aureus are addressed in this review. Clinicians should be aware of these aspects, since S. aureus remains one of the most important bacteria in modern medicine

We analyzed surgically resected endocardial specimens from 49 patients by broad-range PCR. PCR results were compared with (1) results of previous blood cultures, (2) results of culture and Gram staining of resected specimens, and (3) clinical data (Duke criteria). Molecular analyses of resected specimens and previous blood cultures showed good overall agreement. However, in 18% of patients with sterile blood cultures, bacterial DNA was found in the resected materials. When data from patients with definite or rejected cases of infective endocarditis (IE) were included, the sensitivity, specificity, and positive and negative predictive values of broad-range PCR were 82.6%, 100%, 100%, and 76.5%, respectively, overall, and 94.1%, 100%, 100%, and 90%, for cases of native valve endocarditis. The sensitivity, specificity, and positive and negative predictive values of culture of resected specimens from patients with native valve endocarditis were 17.6%, 88.9%, 75%, and 36.4%. We recommend broad-range PCR of surgically resected endocardial material in cases of possible IE, in cases of suspected IE in which blood cultures are sterile, and in cases in which organisms grow in blood cultures but only Duke minor criteria are met. We propose to add molecular techniques to the pathologic criteria of the Duke classification scheme

We describe an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) among injection drug users (IDUs). From August 1994 through December 1999, we registered 31 IDUs with MRSA infections (12 with soft-tissue infection, 7 with pneumonia [fatal in 1], 7 with endocarditis [fatal in 1], 2 with osteomyelitis, 2 with septic arthritis, and 1 with ulcerative tonsillitis), with a marked increase in the number of IDUs registered during 1998 and 1999. Of 31 patients, 15 (48%) were infected with human immunodeficiency virus. A point-prevalence study among IDUs who frequented outpatient facilities in Zurich revealed an MRSA carriage rate of 10.3% (range, 0%-28.6%) in various facilities. In all but 1 case, pulsed-field gel electrophoresis banding patterns of isolates obtained from these patients were indistinguishable from isolates of the initial 31 IDUs registered. Risk factors for MRSA carriage were disability and prior hospitalization in a hospice. In summary, MRSA became endemic in IDUs in Zurich as a result of the spread of a single clone. This clone caused major morbidity and was responsible for a lethal outcome in 2 cases