Prevalence of enterococcal groin colonization in patients undergoing cardiac interventions: challenging antimicrobial prophylaxis with cephalosporins in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Cephalosporins are recommended for prophylaxis before transcatheter aortic valve replacement (TAVR). Infective endocarditis (IE) after TAVR is caused by enterococci in up to 30% of cases, particularly early after TAVR. Enterococcal colonization in the groin has been postulated as a source of infection, not only because prophylaxis does not cover enterococci but also because most TAVR procedures are performed by transfemoral access. There are few data analysing the groin microbiome to demonstrate the presence of enterococci. AIM: To assess the prevalence of enterococci in the groins of cardiological patients receiving transfemoral interventions. METHODS: This prospective cohort study was undertaken at University Hospital Basel, Switzerland between February and August 2020. Two skin swabs were taken from the groins of consecutive patients undergoing transfemoral cardiac interventions before the administration of antibiotic prophylaxis; for each patient, swabs were taken before and after groin disinfection. Swabs were analysed in the local microbiological laboratory following validated culture methods. FINDINGS: Of 290 included patients, 245 (84.5%) underwent coronary angiography, 31 (10.7%) underwent TAVR, eight (2.8%) underwent right heart catheterization, five (1.7%) underwent closure of patent foramen ovale, and one (0.3%) underwent a MitraClip procedure. Enterococci were detected before disinfection in 48 patients, enterococci were still cultured after disinfection in three patients, and enterococci were detected after disinfection alone (i.e. not detected before disinfection) in one patient. The prevalence of enterococci was 16.6% before disinfection and 1.4% after disinfection. Patients colonized with enterococci had a significantly higher body mass index and were more likely to be diabetic than uncolonized patients. CONCLUSION: Common enterococcal colonization of the groin, coupled with frequent isolation of enterococci from patients with TAVR-associated IE, provides strong evidence that the current recommendation of antimicrobial prophylaxis with cephalosporins before TAVR should be changed to antimicrobial prophylaxis with a compound that is active against enterococci.

Matching Clostridioides difficile strains obtained from shoe soles of healthcare workers epidemiologically linked to patients and confirmed by whole-genome sequencing.

BACKGROUND: The source of transmission of Clostridioides difficile in healthcare institutions is frequently unknown. The aim of this prospective cohort study was to assess the association between strains cultured from patients and shoe soles of healthcare workers (HCWs), as already shown in the operating theatre, but not on general hospital wards in an acute-care institution. METHODS: We conducted a study at a university tertiary care centre in Switzerland. From October 2019 to July 2020, shoe soles of HCWs were cultured for C. difficile twice per shift while taking care of a patient infected with toxigenic C. difficile. Additional risk factors were assessed by interviewing involved HCWs. Patients' faecal samples were processed by routine microbiological methods. Similarity of the HCWs' and patients' strains was determined by whole-genome sequencing (WGS). RESULTS: A total of 103 HCWs exposed to 42 hospitalized patients participated in the study, providing 206 samples. Contamination of shoe soles with C. difficile was detected in 37 samples (17.8%) of HCWs taking care of patients infected with C. difficile. Overall, transmission was suspected by epidemiological link and matching strains demonstrated by WGS in 74%. CONCLUSIONS: HCWs' shoe soles were positive in 17.8% with C. difficile strains linked epidemiologically and confirmed by WGS to infected patients suggesting potential transmission by HCWs' shoe soles. This pilot study provides sufficient evidence to further evaluate this potential mode of healthcare-associated transmission of C. difficile by a larger clinical trial.

Does high adherence to contact precautions lead to low in-hospital transmission of multi-drug-resistant micro-organisms in the endemic setting?

BACKGROUND: Conflicting results have been published on the impact of contact precautions (CPs) on reduction of transmission of multi-drug-resistant micro-organisms (MDROs) in the endemic setting. Ambiguous definitions coupled with low adherence partly explain these differences. AIM: We prospectively monitored the level of adherence to CPs and aimed to relate it to in-hospital transmission of MDROs. METHODS: Between January 2016 and March 2018, all patients under CPs underwent continuous monitoring of adherence to CPs by routine on-site visits on days 0, 3 and 7 after initiating CPs using a standardized checklist. The protocol included 10 interventions that were routinely checked such as CP sign at the door as well as wearing of gowns and gloves upon entry to the patient room. Patients requiring CPs were defined as colonized or infected with MDROs (meticillin-resistant Staphylococcus aureus (MRSA), non-Escherichia coli extended-spectrum beta lactamase (ESBL) Enterobacterales, vancomycin-resistant enterococci (VRE) and carbapenem-resistant Gram-negative micro-organisms (CRGN)) as well as patients infected with respiratory viruses, norovirus, scabies and hypervirulent strains of Clostridioides difficile. FINDINGS: Overall, data from 13,756 CP records from 1378 visits of 812 patients were analysed. Adherence varied between 93% and 100% for each intervention, except for "separate space for contaminated material" with an adherence of 5.3-6.1%. The incidence of in-hospital transmission during the study period was extremely low for MRSA, VRE, non-E.coli ESBL Enterobacterales and CRGN with 0.00-0.064 cases/1000 patient days. CONCLUSION: High adherence coupled with continuous monitoring of CPs correlated with a very low in-hospital transmission rate. These results indicate that CPs are highly effective if routine monitoring of adherence is implemented.

Practical recommendations for routine cleaning and disinfection procedures in healthcare institutions: a narrative review.

Healthcare-associated infections (HAIs) are the most common adverse outcomes due to delivery of medical care. HAIs increase morbidity and mortality, prolong hospital stay, and are associated with additional healthcare costs. Contaminated surfaces, particularly those that are touched frequently, act as reservoirs for pathogens and contribute towards pathogen transmission. Therefore, healthcare hygiene requires a comprehensive approach whereby different strategies may be implemented together, next to targeted, risk-based approaches, in order to reduce the risk of HAIs for patients. This approach includes hand hygiene in conjunction with environmental cleaning and disinfection of surfaces and clinical equipment. This review focuses on routine environmental cleaning and disinfection including areas with a moderate risk of contamination, such as general wards. As scientific evidence has not yet resulted in universally accepted guidelines nor led to universally accepted practical recommendations pertaining to surface cleaning and disinfection, this review provides expert guidance for healthcare workers in their daily practice. It also covers outbreak situations and suggests practical guidance for clinically relevant pathogens. Key elements of environmental cleaning and disinfection, including a fundamental clinical risk assessment, choice of appropriate disinfectants and cleaning equipment, definitions for standardized cleaning processes and the relevance of structured training, are reviewed in detail with a focus on practical topics and implementation.

Impact of an infection control service in a university psychiatric hospital: significantly lowering healthcare-associated infections during 18 years of surveillance.

BACKGROUND: Healthcare-associated infections (HAIs) lead to high morbidity and mortality. Data for HAIs in psychiatric hospitals are scarce, and are not derived from long-term surveillance. AIM: To assess the impact of an infection control service on the prevalence of HAIs in a psychiatric hospital over an 18-year period. METHODS: In 1999, a professional infection control service was initiated at the University Psychiatric Hospital in Basel, Switzerland, with a part-time infection control nurse, a hospital epidemiologist, and administrative support. In addition to monitoring rates of multi-drug-resistant pathogens, eight prevalence studies using definitions outlined by the Centers for Disease Control and Prevention (CDC) were conducted between 2001 and 2018. For the primary outcome, a Poisson regression model was fitted to confirm cases of HAIs, standardized for patients at risk as a model offset. FINDINGS: Overall, the predicted prevalence of nosocomial infections decreased from 3.7% (95% confidence interval (CI) 2.2-5.3%) in 2001 to 1.0% (95% CI 0.2-1.8%) in 2018 after introduction of an infection control service (incidence ratio rate (IRR) for yearly decrease of 0.93, 95% CI 0.87-0.98, P=0.007). CONCLUSIONS: Implementation of an infection control service may lead to a significant long-term decrease in HAIs, even in an institution caring for patients with low risk for HAIs, such as in psychiatric hospitals. In addition, epidemics and clusters were rapidly contained. Infection control services from acute-care hospitals should be expanded to psychiatric institutions, in order to decrease the incidence of HAIs and meet new challenges in times of emergence of multi-drug-resistant pathogens.

Time-dependent differences in management and microbiology of orthopaedic internal fixation-associated infections: an observational prospective study with 229 patients.

OBJECTIVES: Little information has been published on orthopaedic internal fixation-associated infections. We aimed to analyse time-dependent microbiology, treatment, and outcome. METHODS: Over a 10-year period, all consecutive patients with internal fixation-associated infections at the University Hospital of Basel, were prospectively followed and clinical, microbiological and outcome data were acquired. Infections were classified as early (0-2 weeks after implantation), delayed (3-10 weeks), and late (>10 weeks). RESULTS: Two hundred and twenty-nine patients were included, with a median follow-up of 773 days (IQR 334-1400). Staphylococcus aureus was the most prevalent pathogen (in 96/229 patients, 41.9%). Enterobacteriaceae were frequent in early infections (13/49, 26.5%), whereas coagulase-negative staphylococci (36/92, 39.1%), anaerobes (15/92, 16.3%) and streptococci (10/92, 10.9%) increased in late revisions. Failure was observed in 27/229 (11.7%). Implants were retained in 42/49 (85.7%) in early, in 51/88 (57.9%) in delayed, and in 9/92 (9.8%) in late revisions (p < 0.01). Early revisions failed in 6/49 (12.2%), delayed in 9/88 (10.2%), and late in 11/92 (13.0%) (p 0.81). Debridement and retention failed in 6/42 (14.3%) for early, in 6/51 (11.8%) for delayed, and in 3/9 (33.3%) for late revisions (p 0.21). Biofilm-active antibiotic therapy tailored to resistance correlated with improved outcome for late revisions failure (6/72, 7.7% versus 6/12, 50.0%; p < 0.01) but not for early revisions failure (5/38, 13.2% versus 1/11, 9.1%; p 1.0). CONCLUSIONS: Treatment of internal fixation-associated infections showed a high success rate of 87-90% over all time periods. Implant retention was highly successful in early and delayed infections but only limited in late infections.

Overall bioburden by total colony count does not predict the presence of pathogens with high clinical relevance in hospital and community environments.

BACKGROUND: Healthcare-associated infections (HAIs) affect millions of patients, increasing morbidity and mortality. Pathogens of HAIs originate from both the patient's own flora and the environment, including multi-drug-resistant organisms. AIMS: To determine the bioburden on different types of high-touch surfaces, and to identify cultures to species level and stratify strains into those of low and high clinical relevance. DESIGN: Association between bioburden and presence of pathogens of high clinical relevance (PHCR) in a tertiary care centre and urban environment. METHODS: The overall bioburden measured by total colony count (TCC) was assessed using tryptic soy agar contact plates and two selective agars to improve detection of PHCR. Isolates were routinely identified to species level using matrix-assisted laser desorption/ionization - time of flight mass spectrometry (MALDI-TOF). The definition of PHCR was based on listings outlined by the Centers for Disease Control and Prevention. FINDINGS: In total, 1431 contact plates were processed from 477 surfaces: 153 from hospitals and 324 from publicly accessible institutions or devices. At least one PHCR was identified from cultures from 73 samples. TCC was found to be poorly correlated with the presence of PHCR. CONCLUSION: TCC poorly predicted the presence of PHCR, rendering the results from environmental sampling difficult to interpret. MALDI-TOF enables the identification of large numbers of isolates from the environment at low cost. Further studies on environmental contamination should use MALDI-TOF to identify all pathogens grown.

Culture of Bone Biopsy Specimens Overestimates Rate of Residual Osteomyelitis After Toe or Forefoot Amputation.

BACKGROUND: Guidelines recommend both histological analysis and culture for definite diagnosis of osteomyelitis. It is not clear if histological and culture criteria can be used interchangeably in the clinical scenario of toe amputation. We therefore prospectively compared the results of intraoperative culture and those of histological examination in this setting. METHODS: Consecutive patients requiring toe or forefoot amputation at the University Hospital Basel during a 2-year period were included in the study. Biopsy specimens from the residual bone were cultured according to microbiological standards. Histological analysis was performed using standardized criteria for osteomyelitis. Clinical outcomes were assessed retrospectively via chart review. RESULTS: Of 51 patients included in the study, 33 (65%) had a positive culture of residual bone and 14 (27%) showed histological signs of osteomyelitis. A negative histological result but a positive culture was found for 21 (41%) of the patients, suggesting that culture has a high false-positive rate if histological analysis is used as the reference to rule out osteomyelitis. The recommended criteria of both positive histological findings and positive culture were fulfilled by 12 (24%) of the 51 patients. CONCLUSIONS: Positive cultures of residual bone after forefoot or toe amputation overestimate the true rate of osteomyelitis as defined by histological analysis, presumably because of contamination from soft tissue at the time of surgery. Additional studies are needed to evaluate the indications for, and the duration of, antibiotic treatment according to these findings. CLINICAL RELEVANCE: Our results cast doubt on the strategy of relying solely on culture of bone biopsy specimens when deciding whether antibiotic treatment for osteomyelitis is necessary after toe or forefoot amputation.

Guidance document for prevention of Clostridium difficile infection in acute healthcare settings.

SCOPE: Clostridium difficile infection (CDI) is the most important infective cause of healthcare-associated diarrhoea in high income countries and one of the most important healthcare-associated pathogens in both Europe and the United States. It is associated with high morbidity and mortality resulting in both societal and financial burden. A significant proportion of this burden is potentially preventable by a combination of targeted infection prevention and control measures and antimicrobial stewardship. The aim of this guidance document is to provide an update on recommendations for prevention of CDI in acute care settings to provide guidance to those responsible for institutional infection prevention and control programmes. METHODS: An expert group was set up by the European society of clinical microbiology and infectious diseases (ESCMID) Study Group for C. difficile (ESGCD), which performed a systematic review of the literature on prevention of CDI in adults hospitalized in acute care settings and derived respective recommendations according to the GRADE approach. Recommendations are stratified for both outbreak and endemic settings. QUESTIONS ADDRESSED BY THE GUIDELINE AND RECOMMENDATIONS: This guidance document provides thirty-six statements on strategies to prevent CDI in acute care settings, including 18 strong recommendations. No recommendation was provided for three questions.

New insights into transmission of Clostridium difficile infection-narrative review.

BACKGROUND: Traditionally, Clostridium difficile has been considered a typical healthcare-associated pathogen-that is, one transmitted within healthcare facilities and thus prevented by implementation of standard infection control measures. Recently this concept has been challenged by studies suggesting a relevant role for community acquisition of C. difficile. AIMS: To discusses the current literature, compiled during the last decade, reporting on sources of acquisition of C. difficile and subsequent transmission. SOURCES: The databases PubMed, Medline, Embase and the Cochrane Database were searched for articles published from 1 January 2007 to 30 June 2017 reporting on possible transmission pathways of C. difficile and/or suggesting a source of acquisition of C. difficile. All study types reporting on adult populations were considered; case reports and series were excluded. The PRISMA guidelines for the reporting of systematic reviews were followed. CONTENT: Among 24 original articles included, 63% report on transmission of C. difficile in healthcare settings and 37% investigate sources and transmission of C. difficile in the community. Contact with symptomatic carriers (53.3%), the hospital environment (40.0%) and asymptomatic carriers (20%) were the most commonly reported transmission pathways within healthcare settings. The leading sources for acquisition of C. difficile in the community include direct contact with symptomatic and asymptomatic carriers in the community, including infants (30%) and residents of long-term non-acute care facilities (30%), followed by contact with contaminated environments in outpatient care settings (20%) and exposure to livestock or livestock farms (20%). IMPLICATIONS: In healthcare settings, future control efforts may need to focus on extending cleaning and disinfection procedures beyond the immediate surroundings of symptomatic carriers. Potential targets to prevent acquisition of C. difficile in the community include household settings, long-term care facilities and outpatient settings, while the role of livestock in entertaining transmission requires further investigation.

Temporal trends and epidemiology of Staphylococcus aureus surgical site infection in the Swiss surveillance network: a cohort study.

BACKGROUND: Staphylococcus aureus is the leading pathogen in surgical site infections (SSI). AIM: To explore trends and risk factors associated with S. aureus SSI. METHODS: Risk factors for monomicrobial S. aureus SSI were identified from the Swiss multi-centre SSI surveillance system using multi-variate logistic regression. Both in-hospital and postdischarge SSI were identified using standardized definitions. FINDINGS: Over a six-year period, data were collected on 229,765 surgical patients, of whom 499 (0.22%) developed monomicrobial S. aureus SSI; 459 (92.0%) and 40 (8.0%) were due to meticillin-susceptible S. aureus (MSSA) and meticillin-resistant S. aureus (MRSA), respectively. There was a significant decrease in the rate of MSSA SSI (P = 0.007), but not in the rate of MRSA SSI (P = 0.70). Independent protective factors for S. aureus SSI were older age [≥75 years vs <50 years: odds ratio (OR) 0.60, 95% confidence interval (CI) 0.44-0.83], laparoscopy/minimally invasive surgery (OR 0.68, 95% CI 0.50-0.92), non-clean surgery [OR 0.78 (per increase in wound contamination class), 95% CI 0.64-0.94] and correct timing of pre-operative antibiotic prophylaxis (OR 0.80, 95% CI 0.65-0.98). Independent risk factors were male sex (OR 1.38, 95% CI 1.14-1.66), higher American Society of Anesthesiologists' score (per one-point increment: OR 1.30, 95% CI 1.13-1.51), re-operation for non-infectious reasons (OR 4.59, 95% CI 3.59-5.87) and procedure type: cardiac surgery, laminectomy, and hip or knee arthroplasty had two-to nine-fold increased odds of S. aureus SSI compared with other procedures. CONCLUSIONS: SSI due to S. aureus are decreasing and becoming rare events in Switzerland. High-risk procedures that may benefit from specific preventive measures were identified. Unfortunately, many of the independent risk factors are not easily modifiable.

Secular trends of bloodstream infections during neutropenia in 15 181 haematopoietic stem cell transplants: 13-year results from a European multicentre surveillance study (ONKO-KISS).

OBJECTIVES: Antibacterial resistance is emerging in patients undergoing haematopoietic stem cell transplantation (HSCT), and most data on the epidemiology of bloodstream infections (BSI)-causing pathogens come from retrospective single-centre studies. This study sought to investigate trends in the epidemiology of BSI in HSCT patients from a prospective multicentre cohort. METHODS: We investigated changes in the incidence of causative organisms of BSI during neutropenia among adult HSCT patients for 2002-2014. The data were collected from a prospective cohort for infection surveillance in 20 haematologic cancer centres in Germany, Austria and Switzerland (ONKO-KISS). RESULTS: A total of 2388 of 15 181 HSCT patients with neutropenia (1471 allogeneic (61.6%) and 917 autologous (38.4%) HSCT) developed BSI (incidence 15.8% per year). The incidence of Gram-negative BSI increased over time both in patients after allogeneic HSCT (allo-HSCT) and autologous HSCT (auto-HSCT). BSI caused by Escherichia coli in allo-HSCT patients increased from 1.1% in 2002 to 3.8% in 2014 (3/279 vs. 31/810 patients, p <0.001), and the incidence of BSI caused by enterococci increased from 1.8% to 3.3% (5 vs. 27 patients, p <0.001). In contrast, the incidence of BSI due to coagulase-negative staphylococci decreased in allo-HSCT patients from 8.2% to 5.1%, (23 vs. 40 patients, p <0.001) and in auto-HSCT patients from 7.7% to 2.0% (13/167 vs. 30/540 patients; p = 0.028 for period 2002-2011). No significant trends were observed for the incidence of BSI due to methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci or extended-spectrum ß-lactamase-producing Enterobacteriaceae. The BSI case fatality remained unchanged over the study period (total of 477 fatalities, 3.1%). CONCLUSIONS: The incidence of Gram-negative BSI significantly increased over time in this vulnerable patient population, providing evidence for reevaluating empiric therapy for neutropenic fever in HSCT patients.

Simplifying the WHO 'how to hand rub' technique: three steps are as effective as six-results from an experimental randomized crossover trial.

OBJECTIVES: The World Health Organization (WHO) issued guidelines on hand hygiene recommending a six-step 'how to hand rub' technique for applying alcohol-based hand rub. However, adherence to all six steps is poor. We assessed a simplified three-step technique and compared it to the conventional WHO six-step technique in terms of bacterial count reduction on healthcare workers' hands. METHODS: Thirty-two participants were randomly assigned to clean their hands following the six-step 'how to hand rub' technique (WHO reference group) or a simplified three-step technique (intervention group). Assignments were reversed after 1 day. The degree of bacterial killing was assessed following the European norm for testing hand hygiene products. Hands were contaminated with Escherichia coli, and the mean logarithmic reduction in bacterial counts was compared between both techniques. RESULTS: Bacterial density before hand hygiene performance did not differ between the WHO reference group (median 6.37 log10 CFU, interquartile range (IQR) 6.19-6.54) and the intervention group (median 6.34 log10 CFU, IQR 6.17-6.60, p 0.513). After hand hygiene, the logarithmic reduction factor was higher in the intervention group (median 4.45, IQR 4.04-5.15) compared to the WHO reference group (median 3.91, IQR 3.69-4.62, p 0.021). CONCLUSIONS: The WHO six-step 'how to hand rub' technique can be simplified to a 3-step procedure based on the reduction of bacterial counts on healthcare workers' hands achieved under experimental conditions. The proposed technique is easier to perform and could improve adherence to the execution of hand hygiene action.

Association of daptomycin use with resistance development in Enterococcus faecium bacteraemia-a 7-year individual and population-based analysis.

OBJECTIVE: In this study we aimed to analyse the association between use of daptomycin and MICs of daptomycin in Enterococcus faecium bacteraemia. METHODS: We prospectively enrolled patients aged ≥18 years with E. faecium bacteraemia hospitalized at the University Hospital Basel from 2008 to 2014. We determined daptomycin MICs by Etests and used pulsed field gel electrophoresis to determine clonal relatedness. We recorded the defined daily dosages of daptomycin (DDDs) per 100 patient-days and clinical data from charts. We correlated daptomycin MIC with use of daptomycin in patients with recurrence/persistence. RESULTS: In 195 E. faecium bacteraemias originating from 162 patients the median MIC for daptomycin was 2 mg/L (IQR 2-3); 30% (15.4%) isolates had a MIC ≥4 mg/L and 6 (3.1%) were resistant (MIC >4 mg/L) according to CLSI criteria. The usage of daptomycin increased more than four-fold from 0.36 DDDs/100 patient-days in 2008 to 1.6 in 2014. In 13 of 28 (42.9%) patients with a relapsing or persisting bacteraemia, the daptomycin MIC of the second isolate increased from a median of 2.0 to 2.5 mg/L (p 0.010); 3/13 (23.1%) developed resistance. All patients with the same clone in the first and second episode and an increase of daptomycin MIC had been treated with daptomycin (6/6 versus 1/7 p 0.005). CONCLUSIONS: Daptomycin MICs and Daptomycin usage increased over time. On an individual patient level daptomycin exposure was associated with an increased MIC in subsequent bacteraemia episodes. Diversity did not indicate a clonal origin and argues for a de novo development of resistance.

Outbreak investigation for toxigenic Corynebacterium diphtheriae wound infections in refugees from Northeast Africa and Syria in Switzerland and Germany by whole genome sequencing.

Toxigenic Corynebacterium diphtheriae is an important and potentially fatal threat to patients and public health. During the current dramatic influx of refugees into Europe, our objective was to use whole genome sequencing for the characterization of a suspected outbreak of C. diphtheriae wound infections among refugees. After conventional culture, we identified C. diphtheriae using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and investigated toxigenicity by PCR. Whole genome sequencing was performed on a MiSeq Illumina with >70×coverage, 2×250 bp read length, and mapping against a reference genome. Twenty cases of cutaneous C. diphtheriae in refugees from East African countries and Syria identified between April and August 2015 were included. Patients presented with wound infections shortly after arrival in Switzerland and Germany. Toxin production was detected in 9/20 (45%) isolates. Whole genome sequencing-based typing revealed relatedness between isolates using neighbour-joining algorithms. We detected three separate clusters among epidemiologically related refugees. Although the isolates within a cluster showed strong relatedness, isolates differed by >50 nucleotide polymorphisms. Toxigenic C. diphtheriae associated wound infections are currently observed more frequently in Europe, due to refugees travelling under poor hygienic conditions. Close genetic relatedness of C. diphtheriae isolates from 20 refugees with wound infections indicates likely transmission between patients. However, the diversity within each cluster and phylogenetic time-tree analysis suggest that transmissions happened several months ago, most likely outside Europe. Whole genome sequencing offers the potential to describe outbreaks at very high resolution and is a helpful tool in infection tracking and identification of transmission routes.

Validation of a treatment algorithm for orthopaedic implant-related infections with device-retention-results from a prospective observational cohort study.

Success rates for treatment regimens involving retention of an infected implant are conflicting and failure rates of up to 80% have been reported. We aimed to validate a proposed treatment algorithm, based on strict selection criteria, by assessing long-term outcome of treatment for orthopaedic device-related infection (ODRI) with retention. From January 1999 to December 2009, all patients diagnosed with ODRI at the University Hospital Basel, Switzerland were eligible for treatment with open surgical debridement, implant-retention and antibiotics, if duration of clinical symptoms was ≤3 weeks, the implant was stable, the soft-tissue had no abscess or sinus tract, and the causative pathogen was susceptible to antimicrobial agents with activity against surface-adhering microorganisms. Antimicrobial treatment was administered according to a predefined algorithm. The primary outcome was treatment failure after 2-year follow up. A total of 455 patients were diagnosed with an ODRI, of whom 233 (51.2%) patients were eligible for treatment involving implant-retention. Causative pathogens were mainly Staphylococcus aureus (41.6%) and coagulase-negative staphylococci (33.9%). Among patients with ODRIs related to prostheses, failure was documented in 10.8% (12/111) and in patients with ODRIs related to osteosyntheses, failure occurred in 9.8% (12/122) after 2 years of follow up. In all, 90% of ODRIs were successfully cured with surgical debridement and implant-retention in addition to long-term antimicrobial therapy according to a predefined treatment algorithm: if patients fulfilled strict selection criteria and there was susceptibility to rifampin for Gram-positive pathogens and ciprofloxacin for Gram-negative pathogens.

Low sensitivity of fecal toxin A/B enzyme immunoassay for diagnosis of Clostridium difficile infection in immunocompromised patients.

The optimal approach in laboratory diagnosis of Clostridium difficile infection (CDI) is still not well defined. Toxigenic culture (TC) or alternatively fecal toxin assay by cell cytotoxicity neutralization assay are considered to be the reference standard, but these methods are time-consuming and labor intensive. In many medical centers, diagnosis of CDI is therefore still based on fecal toxin A/B enzyme immunoassay (EIA) directly from stool alone, balancing cost and speed against limited diagnostic sensitivity. The aim of the study was to assess in which patient population the additional workload of TC is justified. All consecutive stool specimens submitted for diagnosis of suspected CDI between 2004 and 2011 at a tertiary-care center were examined by toxin EIA and TC. Clinical data of patients with established diagnosis of CDI were collected in a standardized case-report form. From 12,481 stool specimens submitted to the microbiologic laboratory, 480 (3.8%) fulfilled CDI criteria; 274 (57.1%) were diagnosed by toxin EIA; and an additional 206 (42.9%) were diagnosed by TC when toxin EIA was negative. Independent predictors for negative toxin EIA but positive TC were high-dose corticosteroids (odds ratio (OR) 2.97, 95% confidence interval (CI) 1.50-5.90, p 0.002), leukocytopenia <1000/µL (OR 2.52, 95% CI 1.22-5.23, p 0.013) and nonsevere CDI (OR 2.21, 95% CI 1.39-3.50, p 0.001). There was no difference in outcomes such as in-hospital mortality and recurrence between both groups. In conclusion, negative toxin EIA does not rule out CDI in immunocompromised patients in the setting of relevant clinical symptoms. Methods with improved sensitivity such as TC or PCR should be used, particularly in this patient population.

Is admission screening for Pseudomonas aeruginosa useful in haematologic patients? A prospective study with 1310 patients.

Screening for Pseudomonas aeruginosa is recommended to guide empirical antimicrobial therapy in patients on high-risk units. However, evidence for this approach is scarce. We therefore screened 1310 patients with severe haematologic diseases for P. aeruginosa colonization at admission: 108 (8.2%) were positive, but only nine (0.7%; six with the same clone as in the screening isolate) subsequently developed a P. aeruginosa bloodstream infection (positive predictive value of screening, 8.6%; negative predictive value of screening, 99.5%). Routine screening for P. aeruginosa at admission did not sufficiently predict subsequent bloodstream infections caused by P. aeruginosa.

Rectal swab for detection of norovirus by real-time PCR: similar sensitivity compared to faecal specimens.

Rapid diagnosis and immediate infection control precautions are cornerstones in the prevention of norovirus outbreaks. However, faecal sampling for norovirus PCR--the standard of care--is time consuming. From 2009 to 2011, parallel faecal and rectal swab samples were consecutively obtained from patients with acute gastroenteritis presenting at our emergency department. In total, 109 complete sample pairs of 108 patients were analysed by specific norovirus real-time PCR. The sensitivity of real-time PCR was 97.3% (36/37) for both sampling methods. A rectal swab is a reasonable option for detection of norovirus by real-time PCR, if a stool specimen is not readily available.