Propionibacterium acnes contamination in lumbar disc surgery.

Previous studies have shown that Propionibacterium acnes may be responsible for low-grade infection of the intervertebral discs of patients with severe sciatica. The aim of this study was to prospectively investigate the presence of bacteria in disc fragment samples obtained during surgery for lumbar disc herniation. P. acnes was cultured from disc fragments in two (3.7%) of 54 patients studied. In addition, control cultures taken from ligamentum flavum and muscle from these two patients were also positive for P. acnes. Similar control cultures were positive for P. acnes from a further ten (18.5%) patients. Four air samples taken during surgery all contained P. acnes; the organism was also found from three of 54 laminar flow control cultures. Sample contamination appears the most likely cause for the presence of P. acnes in the lumbar disc fragment cultures.

[Epidemiology of nosocomial infections due to Pseudomonas aeruginosa, Burkholderia cepacia and Stenotrophomonas maltophilia]. / Epidémiologie des infections nosocomiales à Pseudomonas aeruginosa, Burkholderia cepacia et Stenotrophomonas maltophilia.

Non-fermentative Gram negative rods are opportunistic pathogens responsible for nosocomial infections. Using phenotypic markers (serotypes for Pseudomonas aeruginosa and antibiotic susceptibility) allows a preliminary screening of epidemiologically-related strains. However, genotypic markers are necessary to better characterize nosocomial strains for the investigation of outbreaks or cross-transmissions in the hospital setting. Infections due to P. aeruginosa, Burkholderia. cepacia or Stenotrophomonas. maltophilia are usually hospital-acquired and responsible for a high mortality rate as illustrated by the lethality of nosocomial pneumonia due to P. aeruginosa. The severity of these infections is due to the virulence factors of the bacteria and to their occurrence in debilitated patients in whom invasives devices are used. The hospital environment can act as a reservoir with a rate of exogeneous transmission of these bacteria as high as 50% in some studies. To better prevent nosocomial infections related to Gram negative non fermentative rods, the control of the aqueous hospital environment, the strict application of hand disinfection and the investigation of potential cross-transmission in the hospital setting are needed.

Detection of an outbreak of methicillin-resistant Staphylococcus aureus with reduced susceptibility to glycopeptides in a French hospital.

Staphylococcus aureus isolates were screened for reduced susceptibility to glycopeptides with an initial glycopeptide agar screening test, followed by confirmation of the strains thus identified by two Etest strip techniques and population analysis. This procedure detected 48 methicillin-resistant S. aureus (MRSA) isolates with reduced susceptibility to glycopeptides from 24 patients among 883 MRSA isolates tested. The dissemination of a single clone was confirmed by pulsed-field gel electrophoresis.

[Epidemic outbreaks control involving Staphylococcus aureus with reduced sensitivity to glycopeptides]. / Contrôle de phénomènes épidémiques dus à des souches de Staphylococcus aureus de sensibilité diminuée aux glycopeptides.

This study describes two epidemic outbreaks involving Staphylococcus aureus with reduced sensitivity to glycopeptides, one in 2000 involving eight patients and the other in 2001-2002 involving 16 patients. These strains were detected rapidly, thanks to routine screening for the offending organisms in the bacteriology laboratory of our hospital. The clonal character of these strains was confirmed by pulsed field electrophoresis. The management of these epidemic outbreaks confirmed (i) the need for systematic adoption of standard precautions, (ii) the importance of circulating information in combating multi-resistant bacteria, as well as the difficulties in transferring colonised patients to different hospital wards, and (iii) the intermittent nature of S. aureus carriage, resulting in a need for prolonged surveillance of colonised and/or infected patients. In addition, our study underlines the value of a multi-disciplinary approach to the management of diffusion of multi-resistant bacteria.

[Possible implication of student nurses in the transmission of methicillin-resistant Staphylococcus aureus during a nosocomial outbreak]. / Implication potentielle d'étudiants infirmiers dans la transmission de Staphylococcus aureus résistant à la méthicilline lors d'une épidémie nosocomiale.

We report an outbreak of infections due to methicillin-resistant Staphylococcus aureus (MRSA) in a medical unit and the possible implication of student nurses in the dissemination of the epidemic strain. A retrospective epidemiological study looking for hospitalised patients colonised or infected with MRSA from the 1st of June to the 30th of September 2001 in the unit was conducted. An audit of delivered cares and a nasal screening of health care workers (HCW) was performed. Six patients were colonised or infected with a MRSA strain, four of them exhibiting a bacteremia. Six HCW had a nasal carriage of MRSA. Typing of the MRSA strains by pulsed field gel electrophoresis demonstrated an epidemic clone isolated from five of six patients, two student nurses and one HCW not implicated in nursing cares. This report illustrates the risk of nosocomial outbreak linked to cares delivered by student nurses.

[Value of an antibiotic lock for the prevention of bacteremia recurrence from central catheters in chronic hemodialysis]. / Intérêt d'un verrou antibiotique pour la prévention des récurrences de bactériémies à point de départ des cathéters centraux en hémodialyse chronique.

Prospectively since 11/1997, all central venous catheter related bacteremias in our dialysis center (n = 60) was recorded. We systematically tested antibiotic lock technique using pure heparin (1 ml = 5000 Ul) mixed with antibiotic matched to isolated micro-organism after 15 days of systemic antibiotherapy. During 39 months of study, 27 bacteremias were documented from 23 patients. Seventeen locks in 15 patients were performed after each dialysis sessions during one month. Associated tunnel infection did not allow to stop the lock in 3 cases. In the 12 remaining patients, we observed 4 recurrences for 3 patients after the stop of the lock with the same micro-organism in 3 times/4 without modifications of antibiotics sensibility. No septic metastases were notified and the patency of all catheters were respected. The incidence of bacteremias was 4.6 per 1000 catheters days before the lock and 0.88 after, during a mean observation period of 15 months per patients. Sterilisation of infected catheters seems possible and the incidence of bacteremias is reduce by the lock technique without coming out of septic complications or selected micro-organisms.