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Biomedical subjects

D Talon

Publications and source records attributed to D Talon.

At least 55 records · Page 3Linked to original sources
PubMed2002

[Detection of bacterial contamination in platelet concentrates: perspectives].

Bacterial contamination of blood components represents today the highest infectious risk of blood transfusion, the risk is particularly high when it affects platelet concentrates. In France the prevention methods developed over the past six years (donor selection, phlebotomy site preparation, first 30 ml diversion, systematic leuko-reduction...) aimed at limiting the introduction of bacteria in blood and bacterial proliferation. Several methods have been tested for the detection of bacterial contamination in platelet concentrates but none have been generalised. Difficulties were met, due to the necessity of 1) detecting only the platelet concentrates presenting a real infectious risk, when the presence of bacteria is observed in 2.2% (2-4%) of donated blood and 2) guaranteeing the availability of platelet concentrates. New methods have been developed which seem able to bring responses to these difficulties. Several processes are being (or will be) assessed, including automated blood culture, bacterial genomic detection with or without amplification, flow cytometric methods. In parallel, an indirect method able to detect the presence of bacteria, based on oxygen consumption, will also be evaluated. One (or several) of these processes should allow, in the short-term, to detect platelet concentrates presenting an infectious risk. In the future, the interest of bio-chips for bacterial detection in biological fluids must be investigated.

Bacteria↗
PubMed2002

Non-observance of guidelines for surgical antimicrobial prophylaxis and surgical-site infections.

OBJECTIVE: A prospective multicentre study was conducted to assess major aspects of surgical prophylaxis and to determine whether inappropriate antimicrobial prophylaxis was a factor associated (risk or protective factor) with surgical site infection (SSI). METHOD: Surgical prophylaxis practices were assessed by analysing four variables: indication, antimicrobial agent, timing and duration. Univariate and multivariate analyses were carried out to identify predictors of SSI among patient-specific, operation-specific and antimicrobial prophylaxis-specific factors. RESULTS: The frequency of SSI was 2.7% (13 SSI in 474 observations). Total compliance of the prescription with guidelines was observed in 41.1% of cases (195 prescriptions). Of the 139 patients who received an inappropriate drug, 126 (90.6%) received a drug with a broader spectrum than the recommended drug. Prophylaxis was prolonged in 71 (87.7%) of the 81 patients who received prophylaxis for inappropriate lengths of time and 43 (61.4%) of the 70 patients who did not receive prophylaxis at the optimal moment were treated too late. Multivariate analysis clearly demonstrated that SSI was associated with multiple procedures (relative risk 8.5), short duration of prophylaxis (relative risk 12.7) and long-term therapy with antimicrobial agents during the previous year (relative risk 8.8). CONCLUSIONS: The ecological risk of the emergence of resistance associated with the frequent use of broad-spectrum antibiotics and prophylaxis for longer periods was not offset by individual benefit to the patients who received inappropriate prophylaxis.

Adult↗
PubMed2002

Bacteraemia caused by coagulase-negative staphylococci exhibiting decreased susceptibility to teicoplanin.

The purpose of our study was to assess the prevalence of coagulase-negative staphylococci (CoNS) isolates with reduced susceptibility to glycopeptides among the isolates responsible for bloodstream infections and to describe the epidemiology of these isolates. CoNS isolates from bloodstream infections were collected and characterized by analysis of antibiotic susceptibility and restriction fragment length polymorphism using pulsed-field gel electrophoresis. The medical records of patients with positive cultures and trends in glycopeptide use were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. The crude incidence of CoNS bacteraemia was 0.51 per 1000 days of hospitalization. The 15 (28.8%) strains identified as having decreased susceptibility to teicoplanin by the reference method were all hospital-acquired and displayed 13 different DNA patterns. The relative risk of harbouring strains with decreased susceptibility to teicoplanin was 3.55 among patients previously treated with vancomycin (confidence interval 95%: 2.15-5.85). The teicoplanin consumption in our institution was constant and represented about 27% of the glycopeptide consumption in daily defined doses. The implementation of programmes aiming to reduce the unnecessary use of glycopeptides should have a significant impact on the reduced-susceptibility rate because strains probably become resistant as a result of antibiotic pressure.

Adult↗
PubMed2001

Endemicity, molecular diversity and colonisation routes of Pseudomonas aeruginosa in intensive care units.

OBJECTIVE: We carried out a prospective study to evaluate the endemicity of Pseudomonas aeruginosa in intensive care units (ICUs). Pulsed-field gel electrophoresis (PFGE) was used to determine the genotypes of P. aeruginosa isolates. This allowed us to determine the importance of cross-colonisation and the colonisation routes of P. aeruginosa. DESIGN: We screened epidemiological specimens (rectal swab, nose swab and tracheal aspiration) and routine clinical cultures from patients admitted to ICUs during a 2-year period, from 1st January, 1998, to 31st December, 1999. SETTING: The study was carried out in four separate adult ICUs located in the Franche-Comté region of France. These four units admitted a total of 1,500 patients per year. RESULTS: A total of 1686 specimens were collected from 473 patients; 122 of these patients were positive on admission, 351 became positive during hospitalisation. The overall incidence of P. aeruginosa was 15.7 cases per 100 patients and 15.1 cases per 1000 days of hospitalisation. Of 184 patients with at least one ICU-acquired positive clinical culture, 104 had been previously identified as carriers by a similar genotype. Typing of 208 non-replicate isolates revealed 101 major DNA patterns. Approximately 50% of P. aeruginosa carriage or colonisation/infection was acquired via cross-transmission; the other cases probably originated from endogenous sources. CONCLUSION: Cross-colonisation seems to play an important role in the general spread of P. aeruginosa in ICUs.

Bacterial Typing Techniques↗
PubMed2001

[Antibiotic prophylaxis and surgery. Prescription compliance in Franche-Comté with the national reference system].

AIM OF THE STUDY: To evaluate the practice of antibiotic prophylaxis for surgery in the Franche-Comté region of France. MATERIALS AND METHODS: A total of 36 surgical teams (72 pairs surgeons/anaesthesists) participated in data collection. Five variables describing practices concerning antibiotic prophylaxis for surgery were compared to national recommendations: did the surgical procedure require antibiotic prophylaxis and was it carried out? Was the antibiotic used appropriately? Was the timing of the first injection optimal? Was the total duration of the treatment correct? Was the dose correct? RESULTS: Among the 687 operations for which data were collected, 513 (74.7%) that corresponded to class 1 or 2 Altemeier operations for which the Société Française d'Anesthésie et Réanimation (SFAR) had drawn up recommendations were analysed in order to answer these questions. The overall frequency of conformity with the regulations was 40% for these 513 operations. Of the 156 patients who did not receive the recommended antibiotic, 133 (85.5%) received an antibiotic with an activity range wider than that of the recommended antibiotic. The duration of prophylaxis was longer than recommended in 80 (87.9%) out of the 91 patients for whom the duration of antibiotic prophylaxis did not respect the recommendations. CONCLUSIONS: This prospective surveillance showed that less than 50% of patients received an antibiotic prophylaxis that was conformed to the regulations. To ensure the efficiency of prophylaxis and to prevent deleterious effects, such as the emergence of antibiotic-resistant bacteria, the recommendations must be regularly respected. Frequent audits of practices should be carried out by the teams responsible for fighting nosocomial infections.

Adult↗
PubMed2001

[Risk factors and prevention of the acquisition and transmission of glycopeptide resistant enterococci].

We reviewed the literature concerning the role of antibiotic use as a risk factor for glycopeptide-resistant enterococci (VRE) infection/colonisation, to enable us to develop measures for preventing the acquisition and transmission of VRE. We found that the length of stay, the number of stays in hospital and the transfer of patients between hospitals and units were all risk factors for acquiring VRE infection. However, analysis of group and individual data showed that there was also a clear link between vancomycin and third-generation cephalosporin use and the prevalence of VRE colonisation/infection. Evidence for this link was provided by the consistent association and dose-effect relationship observed, and from the frequently consistent variations observed over time. However, it is difficult to give precise recommendations because very few studies have investigated both intrinsic bacterial factors making specific strains more epidemic and the precise characteristics of the conditions determining antibiotic selection pressure. In the absence of this information, and maintaining the prevention measures against cross-contamination which remain a priority, these results suggest that programs aimed at improving the prescription of antibiotics should be initiated in hospitals.

Anti-Bacterial Agents↗
PubMed2001

Evaluation of vancomycin use in a large university-affiliated hospital in eastern France in 1999.

OBJECTIVE: In 1999, we conducted a retrospective drug utilization review to determine the volume and pattern of vancomycin use in a university-affiliated hospital in eastern France. METHODS: Total vancomycin use was determined and expressed as vancomycin courses per 100 admitted patients and defined daily doses (DDD) of vancomycin per 100 patient-days. The indication for vancomycin use was classified as appropriate or inappropriate according to the guidelines issues by the HICPAC. RESULTS: A total of 311 vancomycin courses were given, as 2098 DDD, giving crude incidences of 1.17 courses per 100 admitted patients and of 1.19 defined daily doses per 100 patient-days. The frequency of appropriate courses was 66.7%. Of the 63 inappropriate courses of vancomycin, 39.7% and 28.6% were empiric therapy for nosocomial and community-acquired infections, respectively, 20.6% and 6.3% were specific therapy for nosocomial and community-acquired infections, respectively, and 4.7% were prophylactic. CONCLUSIONS: This study shows that vancomycin use in our hospital resulted in a lower selection pressure than has been reported for US university-affiliated hospitals and that comprehensive programs to improve use of vancomycin are needed in our institution.

Anti-Bacterial Agents↗
PubMed2001

Evaluation of current practices in surgical antimicrobial prophylaxis before and after implementation of local guidelines.

The aim of antibiotic prophylaxis (ABP) is to prevent or at least decrease the incidence of postoperative surgical wound infections. In 1992 and 1995, ABP was the subject of two French consensus conferences. Following these conferences, the local Antibiotics Committee of Hopital Saint-Louis has undertaken a study to evaluate and eventually improve the current practices of ABP. This study was carried out in three steps: a first survey of ABP, the writing of local ABP guidelines and a second survey of ABP after the implementation of these recommendations. Concerning all surgical wards, the first survey found 69% (N = 100/145) of ABP practice is to be inappropriate vs. 18% (N = 25/139) in the second survey. Indications, choice of drugs, selection of dosage, administration timing and treatment duration were significantly improved in the second survey. Writing and implementing local recommendations promoted a more rational use of ABP. In addition, this study allowed Saint-Louis Hospital to set up recommendations for plastic surgery; such recommendations are poorly described in the literature.

Adolescent↗
PubMed2001

Multicentre study on the appropriateness of surgical antibiotic prophylaxis.

A prospective study was conducted to assess the appropriateness of surgical antibiotic prophylaxis. A total of 72 surgeon-anaesthesist pairs participated in data collection, which assessed five variables: did the surgical procedure justify the use of antimicrobial prophylaxis and was it given? was an appropriate agent used?, is the timing of administration optimal?, is the duration of prophylaxis correct?, and is a proper dose given? Of the 687 procedures reviewed, 513 (74.7%) were entered in the analysis. Of these procedures, the rate of totally compliant prescriptions was 41.7%. Among the 117 patients who received an inappropriate drug, 112 (95.7%) received a drug with a broader spectrum of activity than that recommended. Prolonged prophylaxis occurred in 80 (87.9%) of the 91 patients who received prophylaxis with an incorrect duration. In conclusion, compliance with the principles of prophylactic antimicrobial administration should be strictly reviewed and conducting such audits should be part of the routine activity of infection control teams.

Antibiotic Prophylaxis↗
PubMed2001

Pseudomonas aeruginosa: antibiotic susceptibility and genotypic characterization of strains isolated in the intensive care unit.

A prospective study was carried out to assess the incidence and the local antibiotic susceptibility of Pseudomonas aeruginosa in intensive care units (ICUs) and to characterize cross-transmission by using pulsed-field gel electrophoresis as an epidemiologic tool. For this purpose, we screened surveillance cultures and routine clinical cultures from patients admitted to two adult ICUs during a 2-year period. Antibiotic susceptibility was determined by a disk diffusion method. The overall incidence of P. aeruginosa was 19.1 cases per 100 patients. Our findings concerning the antibiotic resistance of clinical isolates were concordant with those of other studies. Genotyping revealed that approximately 53.5% of P. aeruginosa colonization was acquired via cross-transmission; the other cases probably originated from endogenous sources. Cross-colonization seems to make a large contribution to the spread of P. aeruginosa in ICUs.

Adult↗
PubMed2000

Large outbreak in a surgical intensive care unit of colonization or infection with Pseudomonas aeruginosa that overexpressed an active efflux pump.

During a 30-month survey, 55 patients were colonized or infected by a single clone of Pseudomonas aeruginosa in a surgical intensive care unit (ICU). This clone overexpressed an efflux pump system, and its antibiotic resistance pattern was extremely stable as it spread from patient to patient. Pulsed-field gel electrophoresis showed that isolates from different patients were genetically identical or very similar. We were unable to identify an environmental reservoir, but cultures of hand specimens from 2 health care workers were positive. It was not clear whether this carriage was the source of the epidemic or a consequence of it. However, the propagation of the epidemic clone was probably linked to its transmission by the staff from patient to patient. The outbreak was controlled, with difficulty, by strengthening isolation procedures, replacing the antiseptic soap being used by the staff, and changing the antibiotic prescription policy. This observation emphasizes the importance of compliance with hand washing and universal precautions.

Anti-Bacterial Agents↗
PubMed2000

Clinical and molecular epidemiology of chromosome-mediated resistance to third-generation cephalosporins in Enterobacter isolates in eastern France.

OBJECTIVE: To determine both the prevalence of group I beta-lactamase-related resistance and the clinical setting in which resistance to expanded-spectrum cephalosporins occurs. METHODS: Isolates of Enterobacter spp. were sensitivity tested to a range of antibiotics, and selected isolates were DNA fingerprinted by pulsed-field gel electrophoresis. The medical records of all patients with positive cultures for Enterobacter spp. were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. RESULTS: The crude incidence of colonization/infection (n = 315) was 0.51 per 100 patients and 0.73 per 1000 days of hospitalization. The 4-day and 7-day Kaplan-Meier rates of colonization/infection with Enterobacter were estimated to be 7.57% (standard deviation (SD = 3.26%) and 4.16% (SD = 2.88%)), respectively. The time lag to colonization/infection with isolates producing large amounts of Bush group 1 beta-lactamase (HLBL) (27.35 +/- 27.30 days) was significantly different from that to colonization/infection with wild-type isolates (13.59 +/- 17.93 days) (P = 0.036). Ninety-six isolates (30.5%) demonstrated acquired resistance to expanded-spectrum cephalosporins: 34 isolates (10.8%) produced extended-spectrum beta-lactamase, and 62 isolates (19.7%) produced HLBL. The 89 Enterobacter isolates susceptible to third-generation cephalosporins yielded 84 major DNA patterns, and the 45 HLBL isolates yielded 38 major DNA patterns. The risk of colonization/infection with HLBL-producing Enterobacter was higher in cases of antimicrobial treatment with third-generation cephalosporins or a fluoroquinolone, and in cases of urinary tract colonization/infection. CONCLUSIONS: The judicious use in hospitals of both expanded-spectrum cephalosporins and other antibiotics such as fluoroquinolones is necessary to curtail the emergence of resistance in Enterobacter spp.

Cephalosporins↗
PubMed2000

Antibiotic susceptibility and genotypic characterization of Haemophilus influenzae strains isolated from nasopharyngeal specimens from children in day-care centers in eastern France.

OBJECTIVE: To determine the overall carriage rate for Haemophilus influenzae in young children in day-care centers, the frequency of resistance to various classes of antibiotic, and the clonal relationship between isolates of the various resistant phenotypes. METHODS: Nasopharyngeal (NP) specimens were obtained and cultured on chocolate agar with bacitracin. Antibiotic susceptibility testing and serotyping were performed for all isolates. The genetic polymorphism of ampicillin-susceptible and beta-lactamase-producing isolates was studied by pulsed-field gel electrophoresis using SmaI. RESULTS: Of the 596 NP secretion cultures, 152 (25.5%) were positive for H. influenzae. Sixty-four (42.1%) isolates produced beta-lactamase and two (1.3%) were ampicillin resistant but did not produce beta-lactamase. We were unable to serotype 150 isolates; one isolate belonged to capsular serotype e and one to serotype f. Forty-six major DNA patterns were identified among 76 randomized isolates. beta-lactamase producing isolates more frequently showed EP than ampicillin-susceptible isolates P < 10(-4). The frequency of isolates with EP was significantly lower in day-care centers attended by less than 20 children than in those attended by more than 20 children (P = 0.020). CONCLUSIONS: Resistance due to beta-lactamase production has disseminated in some day-care centers, mostly by person-to-person spread but also via the possible conjugal transfer of large plasmids between strains. The size of day-care centers may affect the risk of transmission.

Ampicillin↗
PubMed2000

Clinical and molecular epidemiology of hospital Enterococcus faecium isolates in eastern France. Members of Réseau Franc-Comtois de Lutte contr les Infections Nosocomiales.

We carried out a surveillance study of Enterococcus faecium isolates in the Franche-Comtéregion of France over three years. Clinical and epidemiological strains were characterized by antibiotype and genotype (pulsed field gel electrophoresis, PFGE). Three case-control studies were performed to identify risk factors for colonization/infection with three defined resistant phenotypes (amoxycillin, high-level gentamicin and high-level kanamycin). The crude incidence of colonization/infection was 0.156%, and 68.8% of cases were classified as hospital-acquired. Incidence did not differ according to the type of hospitalization (middle term or acute care). The urinary tract was the major site of infection. Resistance rates were: 45.8% (amoxycillin), 18.7% (high-level gentamicin), 61.4% (high-level kanamycin) and 3.1% (vancomycin). No isolate produced b-lactamase and one isolate carried the vanA gene. PFGE revealed two major epidemic patterns each including resistant strains isolated in different hospitals and during different periods in the study. Previous antimicrobial treatment was not identified as a risk factor for colonization/infection with any resistant phenotype. Despite the low frequency of vancomycin-resistant isolates in this study, resistant strains were widely disseminated and had characteristics enabling them to persist and spread. If these strains acquired the vanA gene, the risk of an outbreak would be large. So, the prevalence of vancomycin-resistant E. faecium in hospitals should be carefully monitored in the future.

Adult↗
PubMed2000

Antibiotic susceptibility and genotypic characterization of methicillin-resistant Staphylococcus aureus strains in eastern France.

We studied changes over four years in the characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in a French university hospital by analysis of antibiotic susceptibility and restriction fragment length polymorphism using pulsed field gel electrophoresis. Changes were considered in relation to regional and national frameworks. The proportion of gentamicin-susceptible methicillin-resistant S. aureus (GS-MRSA) among MRSA increased from 22.6% in 1994 to 86.8% in 1998. We first isolated strains of GS-MRSA susceptible to tobramycin and amikacin (TKS-MRSA) in 1996 from patients in eight wards. The number of TKS-MRSA strains per 100 MRSA was 6.1 in 1997, 14.5 in 1998, and 18.9 in 1999. Pattern A, the major DNA pattern identified, accounted for 78.6% of isolates in 1998. This pattern was found in TKS-MRSA and TKR-MRSA strains, but not in Gentamicin-resistant MRSA strains (GR-MRSA). Fitness analysis showed that GR-MRSA strains had much lower replication rates than GS-MRSA strains, but there was no difference between TKS-MRSA and TKR-MRSA strains. Aminoglycoside consumption remained constant between 1994 and 1998. The spread of TKS-MRSA in our hospital since 1996 may relate to the "total use threshold", as the level of tobramycin/amikacin use is below that required for selection of TKR-MRSA.

Cross Infection↗
PubMed1999

The role of the hospital environment in the epidemiology of multi-resistant bacteria.

The aim of this study was to use published data to assess the importance of the hospital environment as a possible secondary reservoir of multi-resistant bacteria capable of colonizing or infecting patients. This should make it possible to develop appropriate measures for preventing cross contamination in medical environments. Multi-resistant bacteria often contaminate the environment of the colonized or infected patients, and survive for long periods. However, measures proposed to reduce contamination and reduce the potential for cross infection such as disinfection when the patient is discharged, the use of materials with intrinsic antibacterial activity and the wearing of gloves by everyone entering the room whether or not they intend to actually touch the patient, have yet to be evaluated as part of an overall strategy to prevent infection with multi-resistant bacteria.

Bacteria↗