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Biomedical subjects

H Richet

Publications and source records attributed to H Richet.

At least 37 records · Page 2Linked to original sources
PubMed1999

Escherichia coli: epidemiology and analysis of risk factors for infections caused by resistant strains.

This study analyzes the epidemiology of hospital and community-acquired infections caused by Escherichia coli. The antimicrobial resistance pattern was used to characterize the isolates, and a prospective observational study was performed to assess the relationship between antimicrobial use and bacterial resistance. The study was conducted during a 3-month period in a 1,200-bed tertiary care hospital in Nantes, France. An E. coli infection was diagnosed in 3.8% of the patients (507 of 13,384) admitted to the hospital between 1 January and 31 March 1996. Of the 507 isolates, 205 (40.4%) were resistant to at least one antimicrobial; 40% were resistant to amoxicillin, 30% to amoxicillin/clavulanate, 38% to ticarcillin, and 16% to trimethoprim-sulfamethoxazole, while resistance to other antimicrobials was low. Prior receipt of antimicrobial and/or immunosuppressive therapy was significantly associated with infection caused by a resistant organism.

Adolescent↗
PubMed1998

Nosocomial Acinetobacter baumannii infections: microbiological and clinical epidemiology.

BACKGROUND: Acinetobacter baumannii is an important opportunistic pathogen that is rapidly evolving toward multidrug resistance and is involved in various nosocomial infections that are often severe. It is difficult to prevent A. baumannii infection because A. baumannii is ubiquitous and the epidemiology of the infections it causes is complex. OBJECTIVE: To study the epidemiology of A. baumannii infections and assess the relation between fluoroquinolone use and the persistence of multidrug-resistant clones. DESIGN: Three case-control studies and a retrospective cohort study. SETTING: A 20-bed medical and surgical intensive care unit. PATIENTS: Acinetobacter baumannii was isolated from 45 patients in urine (31%), the lower respiratory tract (26.7%), wounds (17.8%), blood (11.1%), skin (6.7%), cerebrospinal fluid (4.4%), and sinus specimens (2.2%). One death was due to A. baumannii infection. MEASUREMENTS: Antimicrobial resistance pattern and molecular typing were used to characterize isolates. The incidence of A. baumannii infection and the use of fluoroquinolones were calculated annually. RESULTS: Initially, 28 patients developed A. baumannii infection. Eleven isolates had the same antimicrobial susceptibility profile, genotypic profile, or both (epidemic cases), and 17 were heterogeneous (endemic cases). A surgical procedure done in an emergency operating room was the main risk factor for epidemic cases, whereas previous receipt of a fluoroquinolone was the only risk factor for endemic cases. The opening of a new operating room combined with the restriction of fluoroquinolone use contributed to a transitory reduction in the incidence of infection. When a third epidemiologic study was done, previous receipt of a fluoroquinolone was again an independent risk factor and a parallel was seen between the amount of intravenous fluoroquinolones prescribed and the incidence of endemic infection. CONCLUSION: Epidemic infections coexisted with endemic infections favored by the selection pressure of intravenous fluoroquinolones.

Acinetobacter↗
PubMed1998

Two epidemiologically related cases of Rahnella aquatilis bacteremia.

Rahnella aquatilis was isolated from the blood cultures of two patients who were in different units of the same hospital. Both isolates were susceptible to aminoglycosides, fluoroquinolones, cotrimoxazole, piperacillin, third generation cephalosporins and amoxicillin-clavulanate, but resistant to amoxicillin, ticarcillin, and first generation cephalosporins. The synergistic activity of amoxicillin and clavulanic acid suggested the presence of a beta-lactamase, confirmed by a positive nitrocefin test and by analytical isoelectric focusing. Pulsed-field gel electrophoresis and ribotyping with the pKK3535 probe showed that the isolates shared the same banding pattern. The results of an epidemiological study suggested that an in-house total parenteral nutrition solution might be the source of this unusual gram-negative rod.

Adult↗
PubMed1998

Bacteriology of chronic purulent secretions in chronic rhinosinusitis.

The aim of this work was to study the bacterial flora of purulent secretions during chronic rhinosinusitis. We studied a total of 533 patients divided into two groups. The control population consisted of 139 adults (> 16 years) of both sexes seen in the community or hospitalized for less than 72 hours for non-rhinological conditions. The rhinosinusitis group consisted of 394 patients referred to the ENT clinic with chronic rhinosinusitis. All the patients with rhinosinusitis had had a post-nasal discharge for at least three months, associated with purulent or mucopurulent secretions originating from the involved sinus cavity. All samples were obtained endonasally under endoscopic guidance from the sinus ostium or from the sinus cavity during surgery. Cultures were positive in 81.3 per cent of the control subjects and 83.1 per cent of the patients with rhinosinusitis. Corynebacteria, coagulase-negative staphylococci, propionibacteria and peptostreptococci were the main commensal organisms, while Haemophilus influenzae, streptococci, Streptococcus pneumoniae, Prevotella spp and Fusobacterium spp were probable causative pathogens. Anaerobes were isolated from approximately 25 per cent of the patients in the rhinosinusitis group. Betalactamase producers represented 27.5 per cent of H. influenzae and 28 per cent of Prevotella spp isolates. Diminished susceptibility to penicillin was found in 13 per cent of S. pneumoniae isolates. The amoxycillin-clavulanate combination was the most active oral antibiotic tested against the pathogenic species in vitro.

Adult↗
PubMed1998

Neutropenic infections: a review of the French Febrile Aplasia Study Group trials in 608 febrile neutropenic patients.

From 1986 to 1992, the Febrile Aplasia Study Group conducted a series of studies involving severely neutropenic patients. The average duration of neutropenia was 21 days, following chemotherapy for leukaemia, or chemotherapy/radiotherapy as part of a conditioning regimen for autologous or allogeneic bone marrow transplantation. A total of 591 evaluable febrile episodes were randomized to treatment with either ceftazidime 3 g daily + amikacin (the reference regimen; n=246), ceftazidime alone (n=98), ceftazidime + vancomycin (n=77), ceftazidime + ciprofloxacin (n=64) or piperacillin/tazobactam + amikacin (n=106). Only three patients treated with the reference dose of ceftazidime died or suffered serious morbidity from infections caused by Gram-negative bacteria. Piperacillin/tazobactam + amikacin was the only antibiotic regimen to have an effect significantly different from the reference regimen. Piperacillin/tazobactam + amikacin produced a higher rate of defervescence at 72 h (P=0.003), fewer days of fever (P < 0.001), fewer superinfections (P=0.018), a less frequent requirement for addition of vancomycin (P=0.01) and a higher incidence of treatment judged to be a 'complete success' (enduring defervescence without a change in antibiotics) (P=0.04). Despite the improved control of Gram-positive microorganisms, the infection-related death rate remained unchanged from 1987 to 1992. An increase in disseminated aspergillosis compensated for the reduction in lethal Gram-positive septicaemia.

Amikacin↗
PubMed1998

[The resistance of Propionibacterium acnes and Staphylococcus epidermidis to cyclines. The Research and Study Group on Acne].

BACKGROUND: A rising percentage of tetracycline-resistant Propionibacterium acnes strains has been reported in the English literature. PATIENTS AND METHODS: We studied a population of 16 patients with acne who had been treated with oral tetracyclines during the preceding year. A bacteriological examination of a skin biopsy was obtained in all patients to determine aerobic and anaerobic flora as wells as resistance to tetracycline and minocycline. RESULTS: Staphylococcus epidermidis strains were frequently resistant to tetracycline (87.5%) as well as minocycline (30%). Tetracycline-resistant Propionibacterium acnes were also observed (7%). Inversely, we were unable to evidence any minocycline-resistant Propionibacterium acnes strains. CONCLUSION: These findings emphasize the importance of determining whether therapeutic response is related or not to the presence of resistant strains.

Acne Vulgaris↗
PubMed1997

[Bacteriological study in acute otitis media].

AIM: A prospective study on bacteriological epidemiology in acute otitis media was conducted in a pediatric hospital emergency service from January 1993 to October 1995. PATIENTS: One hundred and fifty-eight children, aged 6 months to 6 years, with an acute otitis media were included. Culturing and cleansing of the ear canal and tympanocentesis for aspiration and culture of the secretions were performed in 118 children (46 of whom had received antibiotics before for 48 hours). MAIN RESULTS: Middle ear aspirates were sterile in 35% of the children who had not received antibiotics and in 64% of those already treated. Bacteria in middle ear were predominantly Haemophilus influenzae and Streptococcus pneumoniae. Fifty-nine percent of S pneumoniae strains were penicillin-resistant; however, they were responsible for clinical failure in only 8% of cases. No Staphylococcus strains, commensal of the ear canal, could be considered as pathogenic for the middle ear. CONCLUSION: The preciseness with which secretions of middle ear are aspirated reduces the risk of contamination and comparison of ear canal and middle ear cultures allows to identify them. The high ratio of sterile middle ear aspirates after antibiotic treatment raises the question if other factors are responsible for persistent symptoms. The existence of penicillin-resistant S pneumoniae must be known to adjust treatment.

Acute Disease↗
PubMed1996

Bacteriology of the adult middle meatus.

The aim of this work was to assess the commensal flora in the adult middle meatus. Thus, 139 samples were taken from subjects of both sexes, over 16 years of age, seen in the community or hospitalized for less than 72 hours for non-rhinological conditions. They had had no nasal or sinus conditions in the previous three months. One hundred and thirteen samples contained at least one aerobic or anaerobic bacterium. Fifty-nine samples yielded a single organism in culture. A maximum of five organisms were isolated from a given patient. These results show that the adult middle meatus contains a mixed commensal flora and should prove useful in interpreting endonasal swab cultures during acute and chronic sinus infection.

Adolescent↗
PubMed1996

Methicillin-resistant Staphylococcus aureus control in hospitals: the French experience. Association des Pays de la Loire pour l'Eviction des Infections Nosocomiales.

The first cases of isolation of Staphylococcus aureus resistant to methicillin in France were published in 1962. However, until recently, very few epidemiological studies or attempts to control the epidemic have been done in France. In this article, we present the results of a prospective study performed during a 3-month period in 27 hospitals of the Région des Pays de la Loire. Among the 94,605 hospitalized patients included in the study, 0.45% (427) developed methicillin-resistant Staphylococcus aureus (MRSA) infections, the incidence rate ranging from 0% to 1.2%. Thirty-four percent of MRSA-infected patients were 80 years old or older, 30% had been transferred from another service and 19% from another hospital, 56% were hospitalized at least once during the previous year, MRSA had been isolated at least once previously in 18% of MRSA-infected patients, 19% died, 16% were transferred to another service and 11% to another hospital, and only 32% were discharged to their homes. A poor compliance to contact isolation precautions was observed in all hospitals: 46% of MRSA-infected patients were hospitalized in a private room; gloves, masks, and gowns were worn for the care of 63.4%, 14%, and 42.5% of MRSA-infected patients, respectively; and handwashing was feasible in the rooms of 52% of the patients.

Cross Infection↗
PubMed1995

Viridans streptococcal bacteraemia in patients with neutropenia.

Viridans streptococcal bacteraemia is frequent in neutropenic patients. 25 neutropenic patients with viridans streptococcal bacteraemia were compared with 64 control patients. Exposure to repeated chemotherapy or cytarabine were independent risk-factors for streptococcal bacteraemia. The use of carboxyureidopenicillins and a stay in laminar-airflow rooms were protective. In a further cohort study of 49 patients, oral streptococci with the same ribotype as blood isolates were recovered from all 7 bacteraemic patients. The oral cavity is a portal of entry for viridans streptococci bacteraemia in neutropenic patients, especially after oral mucosal damage induced by repeated chemotherapy.

Anti-Bacterial Agents↗
PubMed1994

Fluoroquinolone use and fluoroquinolone resistance: is there an association?

In an assessment of potential risk factors for nosocomial infections caused by fluoroquinolone-resistant gram-negative organisms, 68 patients who developed a nosocomial infection caused by a fluoroquinolone-resistant gram-negative bacillus were compared with 191 patients who developed a nosocomial infection caused by a fluoroquinolone-susceptible gram-negative bacillus. A history of previous infection, immunosuppression, prior receipt of fluoroquinolones, and hospitalization on the burn unit were independent risk factors. Except for immunosuppression, the same risk factors were identified when the 50 patients whose isolates were resistant to fluoroquinolones, aminoglycosides, and beta-lactam antibiotics were compared with the 95 patients whose isolates were susceptible to all of these classes of antimicrobial agents. The identification of hospitalization on the burn unit as a risk factor was attributable to an outbreak of infections caused by a resistant strain of Pseudomonas aeruginosa during the study period. The occurrence of nosocomial outbreaks and the selective pressure of fluoroquinolone use were the main exogenous risk factors involved in the emergence of resistance to fluoroquinolones.

Adolescent↗
PubMed1994

Pseudomonas aeruginosa outbreak in a burn unit: role of antimicrobials in the emergence of multiply resistant strains.

An environmental survey and a cohort study were done to analyze an outbreak of infections in a burn unit caused by a serotype O:11 and a multidrug-resistant serotype O:12 Pseudomonas aeruginosa. The P. aeruginosa O:11 outbreak was controlled by eradicating an environmental source, contaminated hydrotherapy equipment. To assess risk factors for infections caused by P. aeruginosa O:12, 15 infected burn patients were compared with 32 noninfected burn patients hospitalized during the outbreak. Patients had similar extent, severity, location, and care of burn injuries, exposure to invasive procedures, and past history of P. aeruginosa infection. Prior treatment with ceftazidime (3 g/day) was the only independent risk factor for P. aeruginosa O:12 infection. The outbreak was controlled by increasing the daily administration of ceftazidime from 3 to 6 g and by a reinforcement of isolation precautions.

Adult↗
PubMed1993

Should vancomycin be used empirically in febrile patients with prolonged and profound neutropenia? Results of a randomized trial.

OBJECTIVES: We conducted a randomized trial with ceftazidine alone or associated with amikacin or vancomycin to investigate the efficacy of the daily 3 g dosage of ceftazidime and the efficacy of monotherapy with ceftazidime and to determine if vancomycin should be added empirically. METHODS: Patient inclusion criteria were: age over 10 years, therapeutically-induced neutropenia and fever for at least three hours above 38.5 degrees C in absence of a clear non-infectious aetiology. Patients were randomized into three groups: group C, ceftazidime alone 3 g/day; group CA, ceftazidime 3 g/day plus amikacin 15 mg/kg/day; or group C, ceftazidime 3 g/day plus vancomycin 1.5 g/day. RESULTS: Results from one hundred and two episodes of fever were analyzed. The underlying diseases were haematological malignancies (89 patients) and solid tumours (13 patients). The median duration of neutropenia (< 0.5 x 10(9) PMN/L) was 18 days and the minimum duration of 7 days. The main criterion for the analysis of efficacy was the onset of a major infectious event, i.e. death related to documented or suspected infection and any infectious event considered life-threatening or hindering future treatment of the underlying disease. Eight (22%) patients in group C developed major infectious events compared with four (13%) in group CA and none in group CV (p < 0.01). Major infectious events were mainly due to Gram-positive organisms, particularly Streptococcus species. CONCLUSION: We conclude that: 1) ceftazidime alone and in association with amikacin is effective in preventing Gram-negative major infectious events; and 2) vancomycin should not be added only when a Gram-positive infection is documented, but used empirically.

Adolescent↗
PubMed1992

[In vitro kinetics of the activity of fusidic acid and fluoroquinolones combinations against staphylococci according to methicillin-resistance phenotype. Implications for the treatment of osteoarticular infections].

The kinetics of the effect of fusidic acid and of two fluoropiperazinyl quinolones (ofloxacin and pefloxacin), used alone or in combination, on ten methicillin-susceptible or methicillin-resistant strains of staphylococci were studied. Little or no bactericidal effects were seen with fusidic acid. With ofloxacin and pefloxacin, the bactericidal effect was delayed and occurred only with high concentrations. Used in combination, fusidic acid and the fluoroquinolones exhibited no synergistic effects and occasionally antagonized each other in vitro. The methicillin-resistance phenotype of organisms had no influence on results.

Bone Diseases↗
PubMed1990

Prospective multicenter study of vascular-catheter-related complications and risk factors for positive central-catheter cultures in intensive care unit patients.

To determine the incidence rate of complications associated with vascular catheters in intensive care unit patients and to analyze risk factors for a positive vascular culture, we performed a multicenter study of intensive care unit patients at eight French hospitals. During the study period, 865 intravenous catheters were inserted in 566 patients; 362 (41.8%) were peripheral catheters, and 503 (58.2%) were central catheters. Local complications (i.e., infiltration) occurred significantly more often with peripheral than with central catheters (P less than 0.001); in contrast, fever and bacteremia were significantly more often associated with central than with peripheral catheters (P less than 0.01 and P less than 0.05, respectively). The culture of the vascular-catheter tip was positive for 24% of central catheters (32 of 1,000 catheters days) and for 9% of peripheral catheters (21 of 1,000 catheters days). Staphylococcus epidermidis was the most common microorganism isolated from both peripheral and central catheters, followed by Staphylococcus aureus and Pseudomonas aeruginosa. No significant risk factor associated with positive cultures for peripheral catheters was found by univariate analysis. In contrast, the purpose of the cannula (nutrition and monitoring of central venous pressure), the insertion site (jugular), the dressing type (semipermeable transparent dressing), the antiseptic used to prepare the insertion site (povidone iodine), and routine changing of the intravenous administration set were significantly associated with positive cultures of central catheters. Three factors, duration of catheterization, use of a semipermeable transparent dressing, and the jugular insertion site, were found to be independently associated with positive cultures of central catheters by multivariate analysis.

Catheterization↗
PubMed1989

Epidemic Pseudomonas aeruginosa serotype O16 bacteremia in hematology-oncology patients.

From 1 August 1978 through 31 December 1982, 98 hematology-oncology patients had positive cultures for Pseudomonas aeruginosa serotype O16; 22 of these patients developed bacteremia, and this bacteremia was associated with the occurrence of extensive perineal cellulitis in 10 patients (45.5%). Seventeen bacteremic patients died. The epidemic strain differed from other P. aeruginosa organisms isolated at the hospital by its resistance to all antibiotics available at that time (ticarcillin, piperacillin, azlocillin, tobramycin, ceftizoxime, ceftriaxone, moxalactam, ceftazidime, and fosfomycin). Univariate analysis showed the following factors to be significantly associated with P. aeruginosa O16 bacteremia: the severity of granulocytopenia at the time of the bacteremia, more days with fever, the administration of ticarcillin or an aminoglycoside, the receipt of a greater number of antimicrobial agents for a longer period of time before documentation of the bacteremia, and the occurrence of cellulitis. Logistic regression analysis showed that duration of fever, duration of bacteremia, and the number of antimicrobial agents administered before documentation of the bacteremia were the best predictors of P. aeruginosa O16 bacteremia. In a prospective study of the acquisition of P. aeruginosa by hematology-oncology patients, 1,149 specimens (throat and rectal swabs) from 270 patients and 201 specimens from their washbasin drains were collected. On only three occasions was the epidemic strain isolated from both the patient and his or her washbasin, but in each case the colonization of the patient preceded the isolation of the strain from the washbasin. The transmission of any P. aeruginosa organism from washbasin drain to patient could not be documented. Contact isolation precautions from the Centers for Disease Control were used for all hematology-oncology patients colonized or infected with P. aeruginosa after 7 January 1983. No case of P. aeruginosa O16 bacteremia has occurred at Hotel Dieu since July 1984.

Adult↗