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W Zimmerli

Publications and source records attributed to W Zimmerli.

At least 19 recordsLinked to original sources
PubMed2006

Outcome of prosthetic knee-associated infection: evaluation of 40 consecutive episodes at a single centre.

Few studies have compared the long-term success of different surgical strategies in prosthetic knee-associated infection. Accordingly, a retrospective cohort study was performed of 40 episodes in 35 consecutive patients undergoing revision surgery for prosthetic knee-associated infection at a single centre between 1988 and 2003. The median patient age was 70 (44-90) years; the median follow-up period was 28 (2-193) months; 45% of infections were early, 23% were delayed, and 32% were late; and 55% of infections were caused by staphylococci. The probability of survival without prosthesis failure was 92.4% (95% CI, 84.1-100) after 1 year, and 88.7% (95% CI, 78-99.4) after 2 years. Recurrence-free survival was observed in 20 (95%) of 21 patients treated with debridement and retention, in both patients with one-stage exchange, and in 11 (85%) of 13 patients with two-stage exchange. Patients with delayed infection had a worse outcome than those with early or late infection (67% vs. 97%; p < 0.03). Patients with at least partially adequate antimicrobial therapy had a higher success rate than those with inadequate treatment (94% vs. 60%; p 0.069). The outcome was similar for patients with a duration of therapy of 3 to < 6 months, and those with a duration of therapy of > or = 6 months (91% vs. 87% success). Different surgical procedures had similar success rates, provided that the type of infection, the pathogen, the stability of the implant and the local skin and soft-tissue condition were considered. Adherence to an algorithm defining a rational surgical and antibiotic treatment strategy contributed to a favourable outcome.

Adult↗
PubMed2005

[Errors in patients with infections].

Problems in the management of patients with infections are illustrated with three cases. The first case underlines the need for knowledge about antibiotic resistance pattern and mechanisms, as well as about clinical treatment studies for the correct management of endocarditis. The second case shows that results of microbiological samples may provide irrelevant data on which the treatment with suboptimal or wrong antimicrobial agents is based. The third case illustrates that the analysis of an infection should be a continuous process. Each microbiological result should initiate reevaluation, in order to optimize treatment. Criteria for adapting therapy are the in-vitro susceptibility of the infecting agent, the risk of emergence of resistance during treatment, results of published clinical studies, as well as toxicity and price of the antibiotic. All three cases illustrate the impact of an infectious disease specialist who should not only provide clinical knowledge, but also information about microbiology and epidemiology.

Adult↗
PubMed2005

[Implant infections. What must an internist know?].

Implant-associated infections are a major challenge for the primary care physician because the chance of cure depends on the time interval between infection and start of adequate surgical and antimicrobial treatment. On the other hand, rapid therapy should not prevent from correct microbiological sampling. Since long-term antibiotic therapy is required, the microorganism and its susceptibility pattern should be known. Thus, the primary care physician should know signs and symptoms of these rare infections and rapidly involve the specialist. The main task of the specialist is to confirm the diagnosis and to decide whether the implant has to be removed, or whether debridement with retention is a feasible option to eradicate infection. In this review, infections associated to vascular grafts, to pacemakers and to arthroplasties are presented.

Anti-Bacterial Agents↗
PubMed2005

Dynamics of serum procalcitonin in patients after major neurosurgery.

Classical markers of infection cannot differentiate reliably between inflammation and infection after neurosurgery. This study investigated the dynamics of serum procalcitonin (PCT) in patients following major neurosurgery. PCT concentrations remained < 0.2 ng/mL during the post-operative course. In contrast, leukocyte and neutrophil counts, as well as C-reactive protein (CRP) levels, increased significantly post-operatively (leukocytes, range 7.1-23.7 x 10(9)/L, p < 0.001; neutrophils, range 70.8-94.5%, p < 0.001; CRP, median 14 mg/L, range 3-95 mg/L, p < 0.001). Analysis of PCT levels using assays with improved sensitivity may be useful in the diagnosis of neurosurgical patients with post-operative fever of unknown origin.

Adult↗
PubMed2005

[Antibiotic prophylaxis for late blood-borne infections of joint prostheses].

By analogy with endocarditis prophylaxis, patients with joint prostheses are often given antibiotics before invasive procedures or dental treatment. However, this analogy is not justified: The pathogenesis and bacterial spectrum of infections of artificial joints differ from those of endocarditis. Since the efficacy of administering prophylactic antibiotics to patients with joint prostheses has never been scientifically proven, there is no general indication for such prophylaxis. On the other hand, infections in other parts of the body should be actively sought and treated promptly. Prophylactic antibiotic administration may be appropriate in individual cases during a procedure in patients who are at increased risk of a haematogenic prosthesis infection as a result of bacteraemia. For operations routinely performed under perioperative antibiotic cover, the same prophylaxis should also be used for patients with joint prostheses.

Antibiotic Prophylaxis↗
PubMed2004

[Fever, malaise and new onset mitral valve insufficiency. Subacute Streptococcus bovis mitral valve endocarditis ].

A 62-year-old patient with low grade fever, fatigue, arthralgia and newly discovered mitral regurgitation was diagnosed with subacute endocarditis. Streptococcus bovis grew from all six blood culture bottles. Streptococcus bovis is known to be associated with gastrointestinal neoplasias. Therefore a colonoscopy was performed and two polyps were removed. Histological analysis revealed a tubulovillous adenoma and a serrated adenoma. Colonoscopy is mandatory for all patients with Streptococcus bovis endocarditis even without any symptoms for colorectal neoplasia. The significance of Streptococcus bovis for the carcinogenesis of colorectal neoplasias and the possible alternative pathway for colorectal carcinomas through serrated adenomas will be discussed.

Diagnosis, Differential↗
PubMed2004

[Classification and microbiology of osteomyelitis].

The clinical presentation of osteomyelitis is multifarious. Therefore, patients are diagnosed and treated by various specialists with many different concepts of optimal management. Originally, only the acute and the chronic presentations were differentiated. The classification of Waldvogel, which is based on pathogenetic mechanisms, is more sophisticated. Diabetic foot is classified according to Wagner, who takes into account the continuous progression from sore to ulcer to osteomyelitis to gangrene. The staging according to Cierny-Mader is the most useful for the therapeutic management by surgeons. The spectrum of microorganisms is variable according to the type of osteomyelitis, epidemiology, age of the patient, co-morbidity, microbiological technique (culture, PCR), and duration of the infection. S. aureus is the leading pathogen in each type of osteomyelitis. Over the past 20 years, antimicrobial resistance has become an increasing problem. In case of osteomyelitis, standard susceptibility testing can be inaccurate. In case of device-related infection or in any type of chronic osteomyelitis, antimicrobial agents must be efficacious on stationary-phase and adhering microorganisms. Microbiologic culture and susceptibility testing should always be performed, in order to optimize the antimicrobial therapy.

Anti-Bacterial Agents↗
PubMed2004

[Diagnosis and follow-up management of postoperative bacterial osteitis].

Osteomyelitis is a term used to describe bone infection. As a complication, it can occur after open bone fracture and is associated with the implantation of foreign material. Acute disease after surgery starts after about 7 days to 4 weeks, and is characterized by a suppurative infection. Chronic infection sometimes manifests even years after surgery with a purulent sinus tract. Diagnosis is based on clinical signs, microbiological culture, histological evidence of the presence of granulocytes, and on radiological signs of osteomyelitis. However, it is sometimes difficult to distinguish between merely soft tissue involvement and osteomyelitis, especially in the presence of implanted material. Management includes a thoroughly surgical débridement and antibiotic treatment. Though frequently used, bacterial cultures of swabs of superficial wounds or fistulas are often misleading, whereas needle biopsy or surgical sampling with at least three tissue samples provides more reliable information. Because of the prolonged antibiotic treatment, it is mandatory for a successful outcome to culture the microorganism in order to determine antibiotic susceptibility. In addition to conventional radiological approaches, magnetic resonance imaging has become useful for the diagnosis of osteomyelitis. Despite significant progress in antibiotic therapy and orthopedic surgery, osteomyelitis remains difficult to treat and often relapses, even after years.

Anti-Bacterial Agents↗
PubMed2004

Management of infection associated with total hip arthroplasty according to a treatment algorithm.

BACKGROUND: An algorithm for the management of hip arthroplasty-associated infections was validated in a cohort study. PATIENTS: 60 patients with 63 episodes of total hip arthroplasty-associated infections observed from 1985 to 2001 were included. The treatment algorithm was based on the time of manifestation, pathogenesis, and condition of implant and soft tissue. Three treatment options were proposed, namely debridement with retention, one-stage and two-stage replacement. RESULTS: The median patients' age was 72 years, the median follow-up 28 months; 29% were early, 41% delayed, and 30% late infections, 57% of the infections were exogenously and 43% hematogenously acquired. The overall success rate for the first treatment attempt was 83% (52/63). Patients treated according to the algorithm had a better outcome than the others (44/50 = 88% vs 8/13 = 62%, Relative risk (RR) 0.31, 95% confidence interval (CI): 0.11-0.86, p < 0.03); those treated with adequate antimicrobial therapy had a better success rate (87% vs. 50%, p < 0.01). CONCLUSION: The proposed algorithm defines a rational surgical/antibiotic treatment strategy.

Aged↗
PubMed2003

Management of infection associated with prosthetic joints.

In orthopedic implant surgery, infection is rare, but difficult to eradicate. Neither diagnosis nor treatment of such infections is standardized. A MEDLINE search with the keywords "orthopedic implant-related infection" and "joint replacement and infection" identified studies published from 1982-2002. One single randomized controlled trial could be found. In addition, larger retrospective case series and observational studies with clear definition of the observed intervention were also selected for inclusion. A rational algorithm based on clinical experience in orthopedic implant-related infections, observational studies and the controlled trial is presented. The conditions for the different therapeutic options (debridement with retention, one-stage exchange, two-stage exchange, removal without reimplantation or suppressive antibiotic treatment) are presented. The proposed algorithm is based on the interval after implantation (early, delayed, late), the type of infection (exogenous vs hematogenous), the condition of the implant and the soft tissue, as well as comorbidity of the patient. Considering both surgical and antimicrobial therapy, our algorithm facilitates either retrospective evaluation of case series or the planning of well-defined prospective studies.

Aged↗
PubMed2002

Clustering of bloodstream infections during maggot debridement therapy using contaminated larvae of Protophormia terraenovae.

BACKGROUND: The treatment of human wounds with fly larvae is an ancient procedure recently reintroduced into medical practice under the term of biosurgery. The crucial technical problem of biosurgery is asepsis of the larvae. PATIENTS AND METHODS: Since February 1999, we conducted a prospective observational study on the use of maggot debridement therapy in the management of ulcers refractory to standard treatment. RESULTS: During the first 5 months we observed five bloodstream infections (four with Providencia stuartii and one with Candida albicans) in 24 patients (21%) treated with maggots. The blood isolates could be traced back to contaminated maggots. Accordingly, the disinfecting procedure of the maggots was optimized and the fly species was changed from Protophormia terraenovae to Phaenicia (Lucilia) sericata. With the new procedure, no case of sepsis occurred in 45 patients treated between January 2000 and December 2001 (p < 0.005). CONCLUSION: Despite promising benefits, maggot debridement therapy can be threatened by serious infectious complications. With an appropriate disinfecting procedure, maggots free of pathogens can be obtained. Provided the maggots have been effectively disinfected, their application on chronic ulcers seems to be safe.

Aged↗
PubMed2001

[Para-infectious vasculitis].

Vasculitis is histologically characterized by inflammatory infiltrates of the vessels. In case of secondary vasculitis, the etiology is known. It may be an infection, a neoplasia, drugs or an autoimmune disease. In contrast, in primary vasculitis, no triggering event can be detected. In case of vasculitis associated to infection, the skin lesion may be the clue for the underlying infection. In case of endocarditis (Osler node, Janeway lesion) or sepsis due to Pseudomonas aeruginosa (ecthyma gangrenosum), the skin lesions are quite specific for the underlying disease. Other skin lesions are just an unspecific reaction to a microbial stimulus. Five clinical examples of vasculitis associated to infection, and an important non-infectious differential diagnosis are presented. The cases underline that a broad general work-up with multiple serological tests is neither cost-effective nor diagnostically rewardable. In contrast, if vasculitis is suspected to be caused by infection, the individual work-up should be based on the case-history, the epidemiology and the clinical presentation.

Adult↗
PubMed2001

Nocardial brain abscess: observation of treatment strategies and outcome in Switzerland from 1992 to 1999.

BACKGROUND: Brain abscesses caused by Nocardia spp. are rare, but life-threatening infections that are notoriously difficult to diagnose and treat and which occur mainly in immunocompromised patients. Standard treatment guidelines are not available. METHODS: A systematic search for nocardial brain abscesses from 1992 to 1999 was conducted in Switzerland for the comparison of clinical presentation, treatment strategies and outcome. RESULTS: Seven cases were found, for which data of six were available. In 4/6 patients antimicrobial therapy led to a decrease in the size of abscesses. Four of six patients died. The cause of death was likely due to underlying co-morbidities, rather than the nocardial infection. CONCLUSION: The finding that treatment was different in each case underscores the lack of therapeutic guidelines.

Adult↗
PubMed2001

[Pneumonia in patients with HIV infection].

Pneumonia is the leading HIV-associated infection. It may occur at an early stage of HIV-infection. The spectrum of microorganisms includes bacteria, mainly Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and Mycobacterium tuberculosis. In addition, fungi such as Pneumocystis carinii, Cryptococcus neoformans and Histoplasma capsulatum are common HIV-associated pathogens. The diagnostic work-up depends on the epidemiology (travel history) and the immune status (CD4-lymphocytes). Imaging techniques are always required, and the microbiological analysis of expectorations should be performed. In patients with < 200/microliter CD4-lymphocytes, a bronchoalveolar lavage is generally required. If tuberculosis is suspected, a CT-scan and a transbronchial biopsy should be performed, irrespective of the CD4-lymphocyte counts. During treatment of Pneumocystis-carinii-pneumonia, the possibility of sulpha resistance (i.e. mutations in dihydropteroate synthase) should be considered. The primary and secondary prophylaxis against opportunistic pathogens can be discontinued in patients with effective antiretroviral therapy, as soon as CD4-lymphocytes persistently (> 3 months) remain above threshold levels.

AIDS-Related Opportunistic Infections↗
PubMed2001

Impact of the regulatory loci agr, sarA and sae of Staphylococcus aureus on the induction of alpha-toxin during device-related infection resolved by direct quantitative transcript analysis.

The cytotoxic alpha-toxin (encoded by hla) of Staphylococcus aureus is regulated by three loci, agr, sarA and sae, in vitro. Here, we assess the regulation of hla in a guinea pig model of device-related infection by quantifying RNAIII (the effector molecule of agr) and hla directly in exudates accumulating in infected devices without subculturing of the bacteria. LightCycler reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the transcripts. Strains RN6390 and Newman expressed considerably smaller amounts of RNAIII in the guinea pig than during in vitro growth. The residual RNAIII expression decreased during the course of infection and was negatively correlated with bacterial densities. As with RNAIII, the highest hla expression was detected in both strains early in infection. Even in strain Newman, a weak hla producer in vitro, a pronounced expression of hla was observed during infection. Likewise, four S. aureus isolates from cystic fibrosis (CF) patients expressed Q1hla despite an inactive agr during device-related infection as in the CF lung. Mutation of agr and sarA in strain Newman and RN6390 had no consequence for hla expression in vivo. In contrast, the mutation in sae resulted in severe downregulation of hla in vitro as well as in vivo. In conclusion, S. aureus seems to be provided with regulatory circuits different from those characterized in vitro to ensure alpha-toxin synthesis during infections.

Animals↗
PubMed2001

Lenercept (p55 tumor necrosis factor receptor fusion protein) in severe sepsis and early septic shock: a randomized, double-blind, placebo-controlled, multicenter phase III trial with 1,342 patients.

OBJECTIVE: Phase III study to confirm a trend observed in a previous phase II study showing that a single dose of lenercept, human recombinant p55 tumor necrosis factor receptor-immunoglobulin G1 (TNFR55-IgG1) fusion protein, decreased mortality in patients with severe sepsis or early septic shock. DESIGN: Multicenter, double-blind, phase III, placebo-controlled, randomized study. SETTING: A total of 108 community and university-affiliated hospitals in the United States (60), Canada (6) and Europe (42). PATIENTS: A total of 1,342 patients were recruited who fulfilled the entry criteria within the 12-hr period preceding the study drug administration. INTERVENTION: After randomization, an intravenous dose of 0.125 mg/kg lenercept or placebo was given. The patient was monitored for up to 28 days, during which standard diagnostic, supportive, and therapeutic care was provided. MEASUREMENTS AND MAIN RESULTS: The primary outcome measure was 28-day all-cause mortality. Baseline characteristics were as follows: a total of 1,342 patients were randomized; 662 received lenercept and 680 received placebo. The mean age was 60.5 yrs (range, 17-96 yrs); 39% were female; 65% had medical admissions, 8% had scheduled surgical admissions, and 27% had unscheduled surgical admissions; 73% had severe sepsis without shock, and 27% had severe sepsis with early septic shock. Lenercept and placebo groups were similar at baseline with respect to demographic characteristics, simplified acute physiology score II-predicted mortality, profiles of clinical site of infection and microbiological documentation, number of dysfunctioning organs, and interleukin-6 (IL-6) plasma concentration. Lenercept pharmacokinetics were similar in severe sepsis and early septic shock patients. Tumor necrosis factor was bound in a stable manner to lenercept as reflected by the accumulation of total serum tumor necrosis factor alpha concentrations. There were 369 deaths, 177 on lenercept (27% mortality) and 192 on placebo (28% mortality). A one-sided Cochran-Armitage test, stratified by geographic region and baseline, predicted 28-day all-cause mortality (simplified acute physiology score II), gave a p value of .141 (one-sided). Lenercept treatment had no effect on incidence or resolution of organ dysfunctions. There was no evidence that lenercept was detrimental in the overall population. CONCLUSION: Lenercept had no significant effect on mortality in the study population.

APACHE↗