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Biomedical subjects

Louis Bernard

Publications and source records attributed to Louis Bernard.

At least 19 recordsLinked to original sources

Prevention of urinary tract infection in spinal cord-injured patients: safety and efficacy of a weekly oral cyclic antibiotic (WOCA) programme with a 2 year follow-up--an observational prospective study.

POPULATION: Spinal cord injury (SCI) patients with neurogenic bladder have an increased risk for symptomatic urinary tract infection (UTI). Recurrent UTI requires multiple courses of antibiotic therapy, markedly increasing the incidence of multidrug-resistant (MDR) bacteria. METHODS: During an observational prospective study, we determined the safety and efficacy of a weekly oral cyclic antibiotic (WOCA) regimen to prevent UTI in SCI adult patients with neurogenic bladder undergoing clean intermittent catheterization. The WOCA regimen consisted of the alternate administration of an antibiotic once per week over a period of at least 2 years. The antibiotics chosen were efficient for UTI, well tolerated and with low selection pressure. RESULTS: There was a significant decrease in antimicrobial consumption linked to the dramatic decrease in the incidence of UTI. Before intervention, there were 9.4 symptomatic UTIs per patient-year, including 197 episodes of febrile UTI responsible for 45 hospitalizations. Under the WOCA regimen there were 1.8 symptomatic UTIs per patient-year, including 19 episodes of febrile UTI. No severe adverse events and no new cases of colonization with MDR bacteria were reported. CONCLUSIONS: In this prospective, observational pilot study a novel approach to the prevention and treatment of UTI in SCI was investigated. Our study shows the benefit of WOCA in preventing UTI in SCI patients.

Adult↗

Suction drainage culture as a guide to effectively treat musculoskeletal infection.

Following surgery for musculoskeletal infection, a positive suction drainage culture (SDC) is consistent with persistent sepsis. Our objective was to determine the effect of a negative SDC obtained in subsequent operations on the outcome of a musculoskeletal infection. 99 patients were prospectively enrolled, all treated surgically for musculoskeletal infection utilizing suction drainage and appropriate antimicrobial therapy. Surgery consisted of irrigation, debridement, and prosthetic exchange or implant removal. SDC was considered negative if all bottles resulted in negative cultures. Following SDC results, patients were placed into 1 of 2 treatment groups: 1) Negative SDC, and no new operation; or 2) Positive SDC, and new operation(s) until SDC was negative. Antibiotic therapy ranged from 6-12 weeks (osteomyelitis) to 10-21 d (soft tissue). Both groups were similar with regard to baseline characteristics. Cure was obtained in 91.8% of patients (56/61) in group 1 and 91.6% of patients (22/24) in group 2. Similar results were obtained in patients with an infection in the presence of an implant. In conclusion, a negative SDC following surgery for a musculoskeletal infection is a strong indication of eventual outcome.

Anti-Bacterial Agents↗

[Infectious diseases risk management].

Surveillance activities first target health problems for which treatment, effective prevention or control measures are available. The data produced by surveillance systems allow prioritising public health actions and defining the objectives of infectious diseases control or prevention. The surveillance of infectious diseases relies on a large number of partners grouped in a public health network in which clinicians have a prominent role. In France, the surveillance of infectious diseases is based on mandatory notification of some diseases, national reference centers, networks of voluntary health professionals and repeated surveys, alerting health authorities in case of threats and identifying the determinants of changes in the population health's status. At hospital, the infectious risk is significant and the risk of epidemic outbreaks very high. A solid system for surveillance is mandatory. An educational program is needed to define the prevention program based on the use of hand disinfection and other standard precautions, antiviral and pneumococcal vaccination. A strong cooperation between general practitioners, healthcare team and relatives is necessary.

Anti-Bacterial Agents↗

[Pathophysiology of infection on orthopedic biomaterials].

Orthopedic biomaterials are foreign bodies and the molecular architecture of their surfaces provides a point of attachment for bacteria. This adherence is made possible through the interaction of the protein interface and the bacterial adhesins. Bacterial colonies use slime and biofilm as means of protection. The development of bacteria towards a reversible state of stationary growth or microcolony variants permits their survival. Microparticles released by biomaterials cause the chronic inflammation associated with the aseptic loosening of prostheses. Some bacterial sub-populations develop transitory resistance to bactericidal antibiotics in the presence of these materials.

Bacterial Infections↗

[Severe Streptococcus agalactiae infection of the diabetic foot. A deleterious role of Streptococcus agalactiae?].

INTRODUCTION: Screening strategies among pregnant women have decreased the incidence of group B Streptococcus, which causes severe neonatal infections. The incidence of these infections has increased among diabetic patients, however. OBJECTIVES: To specify the characteristics of diabetic foot infections in which surgical samples have isolated one or several germs including group B Streptococcus, study its risk factors and determine its course. MATERIALS AND METHODS: We retrospectively evaluated the records of all patients admitted to the University Hospital of Geneva from January 1999 through October 2004, with diagnoses of severe foot infection (+/- osteomyelitis) documented during surgery. RESULTS: Twenty-five severe diabetic foot infections were identified, 21 with osteomyelitis. The most common risk factors were age older than 60 years (n=10), chronic renal failure (n=7), severe arteriopathy (n=6), and immune depression (n=2). Most lesions were classified as grade 3 or 4 of Wagner's classification. 80% of the surgical samples were polymicrobial. Blood cultures were positive in 4 patients, one in septic shock. Half the patients (n=13) underwent amputation, despite initially appropriate antibiotic treatment. No patients died but 3 relapsed. CONCLUSION: Group B streptococcal foot infections often occur in fragile patients with immune depression or severe arterial disease. Despite intensive antibiotic therapy and adequate debridement, amputation is often required in diabetic patients because of severe damage to the tissue and poor vascularization.

Adult↗

The inhibition of neutrophil antibacterial activity by ultra-high molecular weight polyethylene particles.

Following infection, bacterial killing by polymorphonuclear leukocytes (neutrophils) is the main host defense against bacteria. Our hypothesis is that particles of ultra-high molecular weight polyethylene (UHMWP) may impair local neutrophil function and consequently reduce neutrophil bacterial killing. To determine how the in vitro phagocytic-bactericidal activity of neutrophils was affected by exposure to wear particles, tests were run comparing the effects of different particle composition, and different concentrations and sizes of UHMWP particles. There was a significant correlation between the number of particles and the decrease in neutrophil bactericidal activity (p<0.01), and the greatest effect was obtained with a concentration of 10(7) UHMWP/ml. There was a significant decrease in neutrophil bactericidal activity by incubation with particles of 0.1-5 microm (p<0.01), but not with larger size. The results suggest that neutrophil functional defects triggered by the presence of UHMWP particles may potentially contribute to the susceptibility of loose implants to bacterial infections.

Biocompatible Materials↗

Atypical infections in tsunami survivors.

After a tsunami hit Asia in December 2004, 2 survivors had severe infections due to multidrug-resistant and atypical bacteria and rare fungi weeks afterwards. Treating these infections is challenging from a clinical and microbiologic point of view.

Disasters↗

[Severe Streptococcus agalactiae infection of the diabetic foot.]

A DELETERIOUS ROLE OF STREPTOCOCCUS AGALACTIAE?: Introduction Screening strategies among pregnant women have decreased the incidence of group B Streptococcus, which causes severe neonatal infections. The incidence of these infections has increased among diabetic patients, however. OBJECTIVES: To specify the characteristics of diabetic foot infections in which surgical samples have isolated one or several germs including group B Streptococcus, study its risk factors and determine its course. Materials and methods We retrospectively evaluated the records of all patients admitted to the University Hospital of Geneva from January 1999 through October 2004, with diagnoses of severe foot infection (+/- osteomyelitis) documented during surgery. RESULTS: Twenty-five severe diabetic foot infections were identified, 21 with osteomyelitis. The most common risk factors were age older than 60 years (n=10), chronic renal failure (n=7), severe arteriopathy (n=6), and immune depression (n=2). Most lesions were classified as grade 3 or 4 of Wagner's classification. 80% of the surgical samples were polymicrobial. Blood cultures were positive in 4 patients, one in septic shock. Half the patients (n=13) underwent amputation, despite initially appropriate antibiotic treatment. No patients died but 3 relapsed. CONCLUSION: Group B streptococcal foot infections often occur in fragile patients with immune depression or severe arterial disease. Despite intensive antibiotic therapy and adequate debridement, amputation is often required in diabetic patients because of severe damage to the tissue and poor vascularization.

Journal Article↗

Comparative analysis and validation of different assays for glycopeptide susceptibility among methicillin-resistant Staphylococcus aureus strains.

Detection of methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibiting intermediate susceptibility to glycopeptides (GISA) is challenging for clinical microbiology laboratories. We compared three different screening assays for evaluating trends in decreased glycopeptide susceptibility during two periods. Ninety four and ninety five consecutive MRSA blood isolates from 189 bacteremic patients collected during periods A (1989-1994) and B (1999-2001), respectively, were screened in parallel for vancomycin or teicoplanin susceptibility by glycopeptide-containing brain-heart infusion agar (BHIA) tests, Etest MICs performed at a standard (0.5 McFarland) or high (2.0 McFarland) inoculum on Mueller-Hinton (MHA) or BHIA, respectively. Any MRSA isolate yielding <50 CFU (representing <10(-6) of the plated inoculum) on either BHIA containing 2 mg/l of vancomycin (V2-BHIA) or 5 mg/l of teicoplanin (T5-BHIA) was considered as fully susceptible to vancomycin or teicoplanin, respectively. The proportion of MRSA isolates yielding>50 CFU on either V2-BHIA or T5-BHIA significantly (P<0.01) increased from 7/94 (7.4 %) or 8/94 (8.5%) in period A to 16/95 (16.8 %) or 14/95 (14.7%) in period B, respectively. Vancomycin Etests MICs on MHA were of lower sensitivity (<30% and<65%), but high specificity (100% and 99%) on periods A and B isolates, respectively, compared to those on V2-BHIA. Vancomycin Etests MICs on BHIA were of a higher sensitivity (57% and 81%) but lower specificity (91% and 65%) compared to those on V2-BHIA, on periods A and B isolates, respectively, reflecting an unexpectedly high number of false positive isolates on period B isolates (28/95). Screening of decreased susceptibility to vancomycin or teicoplanin on V2-BHIA or T5-BHIA, respectively, may represent simple low-cost alternatives to Etest MICs, minimising the risk of missing potential GISA isolates.

Anti-Bacterial Agents↗

Value of preoperative investigations in diagnosing prosthetic joint infection: retrospective cohort study and literature review.

The diagnosis of a prosthetic joint infection is difficult, but crucial for appropriate treatment. Scintigraphy with specific markers for infection (labelled white cells or immunoglobulin-G) has been reported as a more reliable diagnostic tool than clinical assessment (fever, fistula), laboratory studies (polynuclear neutrophil count, erythrocyte rate sedimentation, and C-reactive protein), and preoperative aspiration. In the first part of this study, we retrospectively reviewed 230 patients admitted with a suspected prosthetic joint infection, and examined the validity of the different diagnostic tools for the group as a whole and for subgroups according to the Coventry classification. In the second part, we reviewed 35 articles about preoperative evaluation of infection in prosthetic joints and compared them to our findings. Our study indicates that C-reactive protein and joint aspiration are the most useful tools to diagnose prosthetic joint infection even in situations of chronic infection (Coventry type II).

Adult↗

High versus standard dose vancomycin for osteomyelitis.

It is important to identify the optimal dosage and best method of infusion of parenteral vancomycin to be used over a several week period for the treatment of osteomyelitis. A retrospective study was undertaken to compare a high dose vancomycin treatment (HD: 40 mg/kg/d) with a standard dose treatment (SD: 20 mg/kg/d), and also to compare the modality of infusion using either intermittent vancomycin infusion (IVI) or continuous vancomycin infusion (CVI). 89 patients with Gram-positive cocci osteomyelitis requiring vancomycin treatment were followed, and the outcome and therapeutic safety were compared. There were significantly more adverse drug reactions (acute renal failure) in the IVI subgroup (HD-IVI vs SD-IVI, p-value 0.007). No cases of renal failure were found in the HD-CVI subgroup. The best outcome was found in the subgroup of patients who received HD-CVI (HD-CVI vs SD-IVI, overall log rank p-value 0.02). HD-CVI treatment appears to provide an improved outcome with fewer adverse drug reactions.

Aged↗

The value of bacterial culture during clean orthopedic surgery: a prospective study of 1,036 patients.

OBJECTIVE: To determine whether bacterial cultures of the wounds of patients undergoing clean orthopedic surgery would help predict infection. METHODS: During 1 year, 1,256 cultures were performed for 1,102 patients who underwent clean orthopedic surgery. Results were analyzed to evaluate their ability to predict postoperative infection. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of the cultures were 38%, 92%, 7%, and 99%, respectively. CONCLUSIONS: Cultures performed during clean orthopedic surgery were not useful for predicting postoperative infection.

Adolescent↗

Trends in the treatment of orthopaedic prosthetic infections.

The most commonly used therapy for prosthetic joint infection is a two-stage prosthetic exchange separated by 6 weeks of intravenous antibiotic therapy. This often results in long periods of hospitalization, morbidity, severe functional impairment and sometimes increased mortality. Therefore novel and challenging therapeutic approaches have been attempted, particularly in hip prosthetic infection. This includes, whenever possible, according to the type of microorganism, antibacterial susceptibility and clinical presentation (including age and comorbidities): (i) less aggressive surgical techniques (debridement and prosthesis retention, or re-implantation with a single-stage exchange arthroplasty); and (ii) antibiotic combinations active against biofilm-associated bacteria, including rifampicin (particularly with quinolones) with excellent bio-availability which allow prolonged and efficient oral therapy.

Anti-Bacterial Agents↗

Effect of vancomycin therapy for osteomyelitis on colonization by methicillin-resistant Staphylococcus aureus: lack of emergence of glycopeptide resistance.

BACKGROUND: In treating orthopedic infections, the long-term impact of vancomycin therapy on colonization by methicillin-resistant Staphylococcus aureus (MRSA) and the emergence of vancomycin-intermediate S. aureus is unknown. DESIGN: Prospective surveillance of the effect of long-term vancomycin therapy on colonization by MRSA and the emergence of vancomycin-intermediate S. aureus. METHODS: Thirty-four patients with MRSA osteomyelitis that was microbiologically documented were longitudinally observed for the emergence of vancomycin-intermediate S. aureus at 3 body sites (wound, anterior nares, and groin) during the initial period of vancomycin therapy and at the 2-month follow-up. Twenty patients received the standard dose (20 mg/kg/d) for 34 +/- 6 days and 14 patients received a high dose (40 mg/kg/d) of vancomycin for 37 +/- 9 days. RESULTS: During vancomycin treatment, global MRSA carriage (all body sites) fell from 100% to 25% in the group of patients receiving the standard dose of vancomycin, and from 100% to 40% in the group receiving the high dose. During the 2-month follow-up period after vancomycin therapy, global MRSA carriage increased from 25% to 55% in the group receiving the standard dose and decreased from 43% to 36% in the group receiving the high dose. CONCLUSION: Therapy with a high dose of vancomycin contributes to the sustained eradication of MRSA carriage without promoting the emergence of glycopeptide resistance.

Adult↗

Relationship between levels of indinavir in hair and virologic response to highly active antiretroviral therapy.

BACKGROUND: Suboptimal levels of antiretroviral drugs result in virologic failure in HIV-infected patients treated with highly active antiretroviral therapy (HAART). OBJECTIVE: To assess the relationship between levels of indinavir in hair and virologic outcome. DESIGN: Cross-sectional study. SETTING: 7 AIDS clinics in France. PATIENTS: 89 HIV-infected patients who received HAART that included indinavir. MEASUREMENTS: Patients were classified as responders or nonresponders on the basis of viremia at the time of hair collection. In nonresponders, levels of indinavir in hair and resistance mutations in the protease gene were assessed at baseline and at the time of indinavir measurement. RESULTS: Mean indinavir levels (+/-SD) were significantly higher in the 65 responders than in the 24 nonresponders (24.4 +/- 16 microg/g vs. 12.9 +/- 8.6 microg/g) (P < 0.001). Nonresponders with intermediate levels of indinavir in hair had more mutations in the protease gene than did nonresponders with low levels of indinavir in hair. CONCLUSION: Indinavir levels in hair are associated with virologic outcome in patients receiving HAART.

Absorption↗