Stefan Erb

Surgical and Antimicrobial Treatment of Prosthetic Vascular Graft Infections at Different Surgical Sites: A Retrospective Study of Treatment Outcomes

Objective Little is known about optimal management of prosthetic vascular graft infections, which are a rare but serious complication associated with graft implants. The goal of this study was to compare and characterize these infections with respect to the location of the graft and to identify factors associated with outcome. Methods This was a retrospective study over more than a decade at a tertiary care university hospital that has an established multidisciplinary approach to treating graft infections. Cases of possible prosthetic vascular graft infection were identified from the hospitals infectious diseases database and evaluated against strict diagnostic criteria. Patients were divided into groups according to the locations of their grafts: thoracic-aortic, abdominal-aortic, or peripheral-arterial. Statistical analyses included evaluation of patient and infection characteristics, time to treatment failure, and factors associated specifically with cure rates in aortic graft infections. The primary endpoint was cure at one year after diagnosis of the infection. Results Characterization of graft infections according to the graft location did show that these infections differ in terms of their characteristics and that the prognosis for treatment seems to be influenced by the location of the infection. Cure rate and all-cause mortality at one year were 87.5% and 12.5% in 24 patients with thoracic-aortic graft infections, 37.0% and 55.6% in 27 patients with abdominal-aortic graft infections, and 70.0% and 30.0% in 10 patients with peripheral-arterial graft infections. In uni- and multivariate analysis, the type of surgical intervention used in managing infections (graft retention versus graft replacement) did not affect primary outcome, whereas a rifampicin-based antimicrobial regimen was associated with a higher cure rate. Conclusions We recommend that future prospective studies differentiate prosthetic vascular graft infections according to the location of the grafts and that rifampicin-based antimicrobial regimens be evaluated in clinical trials involving vascular graft infections caused by staphylococci.

Sonication for diagnosis of catheter-related infection is not better than traditional roll-plate culture: a prospective cohort study with 975 central-venous catheters

This prospective randomized controlled study with 975 nontunneled central venous catheters (CVCs) showed that the semiquantitative roll-plate culture technique (SQC) was as accurate as the sonication method for diagnosis of catheter-related infections. Sonication is difficult to standardize, whereas SQC is simpler, faster, and as reliable as the sonication method for culturing CVCs.

Transmissibility of Clostridium difficile without contact isolation: results from a prospective observational study with 451 patients

Background Contact precautions are recommended by health authorities in Europe and the United States for patients with Clostridium difficile infection (CDI). Recently, the significance of nosocomial transmission has been challenged by screening on admission studies and whole-genome sequencing, providing evidence for an endogenous source of C. difficile. We discontinued contact precautions for patients with CDI, except for patients infected with hypervirulent ribotypes or with stool incontinence, to determine the rate of transmission. Methods From January 2004 to December 2013, contacts of each index case with CDI were screened for toxigenic C. difficile by culturing rectal swabs. Transmission was defined as possible if toxigenic C. difficile was detected in contacts, as probable if the identical polymerase chain reaction ribotype was identified in index–contact pairs, and as confirmed if next-generation sequencing (NGS) revealed clonality of strains. Results Four hundred fifty-one contacts were exposed to 279 index patients nursed in 2-to 4-bed rooms. Toxigenic C. difficile was detected in 6.0% (27/451) after a median contact time of 5 days. Identical ribotypes were identified in 6 index–contact pairs, accounting for probable transmission in 1.3% (6/451). NGS was performed for 4 of 6 pairs with identical strains, and confirmed transmission in 2 contact patients. Conclusions The rate of transmission of toxigenic, predominantly nonhypervirulent C. difficile, was low and no outbreaks were recorded over a 10-year period after discontinuing contact precautions for patients with CDI who were not severely incontinent and who used dedicated toilets. As contact precautions may lead to lower levels of care, their implementation needs to be balanced against the risk of nosocomial transmission.

Increasing prevalence of infectious diseases in asylum seekers at a tertiary care hospital in Switzerland

Objective The increasing number of refugees seeking asylum in Europe in recent years poses new challenges for the healthcare systems in the destination countries. The goal of the study was to describe the evolution of medical problems of asylum seekers at a tertiary care centre in Switzerland. Methods At the University Hospital Basel, we compared all asylum seekers during two 1-year time periods in 2004/05 and 2014/15 concerning demographic characteristics and reasons for referrals and hospitalizations. Results Hundred ninety five of 2’544 and 516 of 6’243 asylum seekers registered at the national asylum reception and procedure centre Basel were referred to the University Hospital Basel in 2004/05 and 2014/15, and originated mainly from Europe (62.3%, mainly Turkey) and Africa (49.1%, mainly Eritrea), respectively. Median age was similar in both study periods (26.9 and 26.2 years). Infectious diseases in asylum seekers increased from 22.6% to 36.6% (p<0.001) and were the main reasons for hospitalizations (33.3% of 45 and 55.6% of 81 hospitalized patients, p = 0.017) in 2004/05 compared to 2014/15. The leading infectious diseases in hospitalized patients were tuberculosis (n = 4) and bacterial skin infections (n = 2) in 2004/05; Malaria (n = 9), pneumonia (n = 6), Chickenpox (n = 5), other viral infections (n = 5) and bacterial skin infections (n = 5) in 2014/15. Infectious diseases like malaria, cutaneous diphtheria, louseborne-relapsing fever or scabies were only found in the second study period. Almost one third of the admitted asylum seekers required isolation precautions with median duration of 6–9.5 days in both study periods. Conclusions The changing demography of asylum seekers arriving in Switzerland in the current refugee crisis has led to a shift in disease patterns with an increase of infectious diseases and the re-emergence of migration-associated neglected infections. Physicians should be aware of these new challenges.

Adverse events of raltegravir and dolutegravir

Objective: To compare the frequency and risk factors of toxicity-related treatment discontinuations between raltegravir and dolutegravir. Design: Prospective cohort study. Methods: All antiretroviral therapy (ART)-naïve and ART-experienced HIV-infected individuals from the Swiss HIV Cohort Study who initiated raltegravir or dolutegravir between 2006 and 2015 were investigated concerning treatment modification within the first year. Results: Of 4041 patients initiating ART containing raltegravir (n = 2091) or dolutegravir (n = 1950), 568 patients discontinued ART during the first year, corresponding to a rate of 15.5 [95% confidence interval (CI) 14.5–16.9] discontinuations per 100 patient-years. Only 10 patients on raltegravir (0.5%) and two patients on dolutegravir (0.1%) demonstrated virologic failure. The main reason for ART discontinuation was convenience expressed as patients wish, physicians decision, or treatment simplification (n = 302). Toxicity occurred in 4.3% of patients treated with raltegravir and 3.6% with dolutegravir, respectively. In multivariable analysis, the only independent risk factor for discontinuing ART because of toxicity was female sex (hazard ratio 1.98, 95% CI 1.45–2.71, P < 0.001). Neuropsychiatric complaints were the most commonly reported toxic adverse events and more frequent in the dolutegravir (n = 33, 1.7%) compared with the raltegravir group (n = 13, 0.6%). Risk of discontinuation for neurotoxicity was lower for raltegravir than for dolutegravir in multivariable analysis (hazard ratio 0.46, 95% CI 0.22–0.96, P = 0.037). Conclusion: In this, large cohort raltegravir and dolutegravir-containing regimen demonstrated a high virologic efficacy. Drug toxicity was infrequent and discontinuation because of neuropsychiatric events within the first year of treatment was only marginal higher with dolutegravir compared with raltegravir. However, monitoring of neurotoxic side-effects of dolutegravir is important.

Growth Patterns of Clostridium difficile – Correlations with Strains, Binary Toxin and Disease Severity: A Prospective Cohort Study

A broad spectrum of symptoms has been associated with C. difficile infection (CDI). Several studies indicate that toxin-production correlates with growth rates of C. difficile. This study aimed to correlate growth rates of C. difficile with disease severity and strain characteristics. From 01/2003 to 10/2011, strains from a prospective cohort of all inpatients with CDI at the University Hospital Basel, Switzerland were analyzed regarding binary toxin, presence of the tcdC deletion and ribotype. Isothermal microcalorimetry was performed to determine growth rates, quantified by the Gompertz function. Ordered logistic regression models were used to correlate disease severity with strain features and clinical characteristics. Among 199 patients, 31 (16%) were infected with binary toxin-producing strains, of which the tcdC gene-deletion nt117 was detected in 9 (4%). Disease severity was classified as mild in 130 patients (65.3%), as severe in 59 patients (29.7%) and as severe/complicated in 10 patients (5.0%). Growth rates were inversely associated with disease severity in univariable (OR 0.514, 95%CI 0.29–0.91, p = 0.023) and multivariable analyses (OR 0.51, 95%CI 0.26–0.97, p = 0.040). While none of the strain characteristics such as presence of the tcdC gene deletion or binary toxin predicted CDI severity, growth rates were inversely correlated with disease severity. Further investigations are needed to analyze growth-regulators and respective correlations with the level of toxin production in C. difficile, which may be important determinants of disease severity.

Multidrug-Resistant Organisms Detected More Than 48 Hours After Hospital Admission Are Not Necessarily Hospital-Acquired.

BACKGROUND Infections and colonization with multidrug-resistant organisms (MDROs) identified >48 hours after hospital admission are considered healthcare-acquired according to the definition of the Centers for Disease Control and Prevention (CDC). Some may originate from delayed diagnosis rather than true acquisition in the hospital, potentially diluting the impact of infection control programs. In addition, such infections are not necessarily reimbursed in a healthcare system based on the diagnosis-related groups (DRGs). OBJECTIVE The goal of the study was to estimate the preventable proportion of healthcare-acquired infections in a tertiary care hospital in Switzerland by analyzing patients colonized or infected with MDROs. METHODS All hospitalized patients with healthcare-acquired MDRO infection or colonization (HAMIC) or according to the CDC definition (CDC-HAMIC) were prospectively assessed from 2002 to 2011 to determine whether there was evidence for nosocomial transmission. We utilized an additional work-up with epidemiological, microbiological, and molecular typing data to determine the true preventable proportion of HAMICs. RESULTS Overall, 1,190 cases with infection or colonization with MDROs were analyzed; 274 (23.0%) were classified as CDC-HAMICs. Only 51.8% of CDC-HAMICs had confirmed evidence of hospital-acquisition and were considered preventable. Specifically, 57% of MRSA infections, 83.3% of VRE infections, 43.9% of ESBL infections, and 74.1% of non-ESBL MDRO infections were preventable HAMICs. CONCLUSIONS The CDC definition overestimates the preventable proportion of HAMICs with MDROs by more than 50%. Relying only on the CDC definition of HAMICs may lead to inaccurate measurement of the impact of infection control interventions and to inadequate reimbursement under the DRG system. Infect. Control Hosp. Epidemiol. 2016;1-6.

Health care provider communication training in rural Tanzania empowers HIV-infected patients on antiretroviral therapy to discuss adherence problems

Self‐reported adherence assessment in HIV‐infected patients on antiretroviral therapy (ART) is challenging and may overestimate adherence. The aim of this study was to improve the ability of health care providers to elicit patients’ reports of nonadherence using a “patient‐centred” approach in a rural sub‐Saharan African setting.

Update of the Swiss guidelines on post-treatment Lyme disease syndrome

Lyme borreliosis is caused by Borrelia burgdorferi sensu lato infection, which responds well to antibiotic therapy in the overwhelming majority of cases. However, despite adequate antibiotic treatment some patients report persisting symptoms which are commonly summarised as post-treatment Lyme disease syndrome (PTLDS). In 2005, the Swiss Society of Infectious Diseases published a case definition for PTLDS. We aimed to review the scientific literature with a special emphasis on the last 10 years, questioning whether the definitions from 2005 are still valid in the light of current knowledge. Furthermore, we describe the clinical history of infection with Borrelia burgdorferi sensu lato, the estimated prevalence of PTLDS, the possible pathogenesis of PTLDS, and treatment options with an emphasis on clinical studies. In summary, we were unable to find a scientific reason for modification of the PTLDS definitions published in 2005. Thus, the diagnostic criteria remain unchanged, namely documented clinical and laboratory evidence of previous infection with B. burgdorferi, a completed course of appropriate antibiotic therapy, symptoms including fatigue, arthralgia, myalgia, cognitive dysfunction or radicular pain persisting for >6 months, a plausible timely association between documented B. burgdorferi infection and onset of symptoms (i.e., persistent or recurrent symptoms that began within 6 months of completion of a recommended antibiotic therapy for early or late Lyme borreliosis), and exclusion of other somatic or psychiatric causes of symptoms. The main therapeutic options remain cognitive behavioural therapy and low-impact aerobic exercise programmes. Growing and unequivocal evidence confirms that prolonged or repeated antibiotic therapy for PTLDS is not beneficial, but potentially harmful and therefore contraindicated. The Guidelines of the Swiss Society of Infectious Diseases offer an evidence based, diagnostic and therapeutic framework for physicians caring for patients suffering from presumptive PTLDS in Switzerland.

Impact of different catheter lock strategies on bacterial colonization of permanent central venous hemodialysis catheters

Thirty-nine hemodialysis patients with permanent central venous catheters were analyzed for bacterial catheter colonization comparing different catheter-lock strategies. The closed needleless Tego connector with sodium chloride lock solution was significantly more frequently colonized with bacteria than the standard catheter caps with antimicrobially active citrate lock solution (odds ratio, 0.22 [95% confidence interval, 0.07-0.71]; P = .011).